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{{use Oxford spelling|date=August 2016}}
{{Use dmy dates|date=January 2024}}
{{Use shortened footnotes|date=May 2023}}{{Infobox event
| title = Chernobyl disaster
| image = IAEA 02790015 (5613115146).jpg
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{{Chernobyl}}
The '''Chernobyl disaster'''
$700 billion USD.<ref>{{Cite report |url=https://globalhealth.usc.edu/wp-content/uploads/2016/01/2016_chernobyl_costs_report.pdf |title=The Financial Costs of the Chernobyl Nuclear Power Plant Disaster: A Review of the Literature |last1=Samet |first1=Jonathan M. |last2=Seo |first2=Joann |date=21 April 2016 |publisher=USC Institute on Inequalities in Global Health |pages=14–15 |language=en |author-link=Jonathan M. Samet |access-date=8 May 2024}}</ref> The
Following the
==
=== Background ===
==== Reactor cooling after shutdown ==== [[File:Decay heat illustration2.PNG|thumb|Reactor [[decay heat]] shown as % of thermal power from time of sustained fission shutdown using two different correlations. Due to decay heat, solid fuel power reactors need high flows of coolant after a fission shutdown for a considerable time to prevent [[Behavior of nuclear fuel during a reactor accident|fuel cladding damage]], or in the worst case, a full [[core melt accident|core meltdown]].]]
In nuclear reactor operation, most heat is generated by [[nuclear fission]], but over 6% comes from [[radioactive decay]] heat, which continues after the reactor shuts down. Continued coolant circulation is essential to prevent core overheating or a [[core meltdown]].<ref>{{cite web |url=http://www.ewp.rpi.edu/hartford/~ernesto/F2011/EP/MaterialsforStudents/Petty/Ragheb-Ch8-2011.PDF |title=Decay Heat Generation in Fission Reactors |first=M. |last=Ragheb |website=University of Illinois at Urbana-Champaign |date=22 March 2011 |access-date=26 January 2013 |archive-url=https://web.archive.org/web/20130514074247/http://www.ewp.rpi.edu/hartford/~ernesto/F2011/EP/MaterialsforStudents/Petty/Ragheb-Ch8-2011.PDF |archive-date=14 May 2013 |url-status=dead }}</ref> [[RBMK]] reactors, like those at Chernobyl, use water as a coolant, circulated by electrically driven pumps.<ref>{{cite web |title=DOE Fundamentals Handbook, Nuclear physics and reactor theory |volume=1 of 2, module 1 |page=61 |publisher=United States Department of Energy |date=January 1996 |url=http://energy.gov/sites/prod/files/2013/06/f2/h1019v1.pdf#page=85.5 |access-date=3 June 2010|url-status=dead |archive-url=https://web.archive.org/web/20140319145623/http://energy.gov/sites/prod/files/2013/06/f2/h1019v1.pdf#page=85.5 |archive-date=19 March 2014 }}</ref><ref>{{cite web |title=Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition (NUREG-0800) |website=United States Nuclear Regulatory Commission |date=May 2010 |url=https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0800/ |access-date=2 June 2010 |archive-url=https://web.archive.org/web/20100619163526/http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0800/ |archive-date=19 June 2010 |url-status=live }}</ref> Reactor No. 4 had 1,661 individual fuel channels,
In case of a total power loss, each of Chernobyl's reactors had three backup [[diesel generator]]s, but they took 60–75 seconds to reach full load and generate the 5.5 MW needed to run one main pump.<ref name="MedvedevZ">{{Cite book |last=Medvedev |first=Zhores A. |author-link=Zhores A. Medvedev |title=The Legacy of Chernobyl |publisher=W.W. Norton & Company |year=1990 |isbn=978-0-393-30814-3 |edition=First American}}</ref>{{rp|15}} Special counterweights on each pump provided coolant via inertia to bridge the gap to generator startup.<ref>{{cite web |last=Dmitriev |first=Viktor |date=30 November 2013 |title=Turbogenerator Rundown |url=http://accidont.ru/rotor.html |url-status=live |archive-url=https://web.archive.org/web/20211003020646/http://accidont.ru/rotor.html |archive-date=3 October 2021 |access-date=19 September 2021 |website=Причины Чернобыльской аварии известны |publisher=N/A |language=ru |quote=На АЭС с реакторами РБМК-1000 используется выбег главных циркуляционных насосов (ГЦН) как самозащита при внезапном исчезновении электропитания собственных нужд (СН). Пока не включится резервное питание, циркуляция может осуществляться за счет выбега. С этой целью для увеличения продолжительности выбега, на валу электродвигателя –привода ГЦН установлен маховик с достаточно большой маховой массой.}}</ref><ref>{{cite web |author=<!--Not stated--> |date=19 September 2021 |title=Main Circulating Pumps |url=http://reactors.narod.ru/rbmk/08_mcp.htm |url-status=live |archive-url=https://web.archive.org/web/20210920212739/http://reactors.narod.ru/rbmk/08_mcp.htm |archive-date=20 September 2021 |access-date=19 September 2021 |website=Справочник "Функционирование АЭС (на примере РБМК-1000)" |publisher=N/A |language=ru |quote=Для увеличения времени выбега на валу электродвигателя установлен маховик.}}</ref> However, a potential safety risk existed in the event that a station blackout occurred simultaneously with the rupture of a
It had been theorized that the rotational momentum of the reactor's [[steam turbine]] could be used to generate the required electrical power to operate the ECCS via the feedwater pumps. The turbine's speed would run down as energy was taken from it, but analysis indicated that there might be sufficient energy to provide electrical power to run the coolant pumps for 45 seconds.<ref name="MedvedevZ"/>{{rp|16}} This would not quite bridge the gap between an external power failure and the full availability of the emergency generators, but would alleviate the situation.<ref name="NV Karpan: 312–13">{{Harvard citation no brackets|Karpan|2006|pp=312–313}}.</ref>
==== Safety test ====
The turbine run-down energy capability still needed to be confirmed experimentally, and previous tests had ended unsuccessfully. An initial test carried out in 1982 indicated that the [[excitation (magnetic)|excitation]] voltage of the turbine-generator was insufficient
A test procedure had been written, but the authors were not aware of the unusual RBMK-1000 reactor behaviour under the planned operating conditions.<ref name=insag7/>{{rp|52}} It was regarded as purely an electrical test of the generator
The test procedure was intended to run as follows:
# The reactor thermal power was to be reduced to between 700 MW and 1,000 MW (to allow for adequate cooling, as the turbine would be spun at operating speed while disconnected from the power grid)
# The steam-turbine generator was to be run at normal operating speed
# Four out of eight main circulating pumps were to be supplied with off-site power, while the other four would be powered by the turbine
# When the correct conditions were achieved, the steam supply to the turbine generator would be closed, which would trigger an automatic reactor shutdown in ordinary conditions
# The voltage provided by the coasting turbine would be measured, along with the voltage and revolutions per minute (RPMs) of the four main circulating pumps being powered by the turbine
# When the emergency generators supplied full electrical power, the turbine generator would be allowed to continue free-wheeling down
==== Test delay and shift change ====
[[File:RBMK en.svg|thumb|upright=2.2|Process flow diagram of the reactor]]
[[File:Gen II nuclear reactor vessels sizes.svg|thumb|upright=
The test was to be conducted during the day-shift of 25 April 1986 as part of a scheduled reactor
The day shift
Soon, the day shift was replaced by the evening shift.<ref name="Karpan44"/>{{rp|3}} Despite the delay, the emergency core cooling system was left disabled. This system had to be disconnected via a manual isolating slide valve,<ref name=insag7/>{{rp|51}} which in practice meant that two or three people spent the whole shift manually turning sailboat-helm-sized valve wheels.<ref name="Karpan44"/>{{rp|4}} The system
At 23:04, the Kiev grid controller allowed the reactor shutdown to resume.
The night shift had very limited time to prepare for and carry out the experiment. [[Anatoly Dyatlov]], deputy chief-engineer of the [[Chernobyl Nuclear Power Plant]] (ChNPP), was present to
==== Unexpected drop of the reactor power ====
The test plan called for a gradual decrease in reactor power to a thermal level of 700–1000 MW,<ref>
{{cite web |url=http://rrc2.narod.ru/book/app7.html |script-title=ru:Рабочая Программа: Испытаний Турбогенератора № 8 Чернобыльской Аэс В Режимах Совместного Выбега С Нагрузкой Собственных Нужд |trans-title=Work Program: Tests of the Turbogenerator No. 8 of the Chernobyl AESP in Run-Off Modes With the Load of Own Needs |website=rrc2.narod.ru |language=ru |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181105215345/http://rrc2.narod.ru/book/app7.html |archive-date=5 November 2018 |url-status=live }}
</ref> and an output of 720 MW was reached at 00:05 on 26 April.<ref name=insag7/>{{rp|53}} However, due to the reactor's production of a fission byproduct, [[xenon-135]], which is a reaction-inhibiting [[neutron absorber]], power continued to decrease in the absence of further operator action, a process known as [[reactor poisoning]]. In steady-state operation, this is avoided because xenon-135 is "burned off" as quickly as it is created
When the reactor power had decreased to approximately 500 MW, the reactor power control was switched from
The reactor was now producing only 5% of the minimum initial power level prescribed for the test.<ref name=insag7/>{{rp|73}} This low reactivity inhibited the burn-off of xenon-135<ref name=insag7/>{{rp|6}} within the reactor core and hindered the rise of reactor power. To increase power, control-room personnel removed numerous control rods from the reactor.<ref>{{Harvard citation no brackets|Dyatlov|2003|p=31}}</ref> Several minutes elapsed before the reactor was restored to 160 MW at 00:39, at which point most control rods were at their upper limits, but the rod configuration was still within its normal operating limit, with Operational Reactivity Margin (ORM) equivalent to having more than 15 rods inserted. Over the next twenty minutes, reactor power would be increased further to 200 MW.<ref name=insag7/>{{rp|73}}
The operation of the reactor at the low power level was accompanied by unstable core temperatures and coolant flow, and, possibly, by instability of [[neutron flux]]. The control room received repeated emergency signals regarding the low levels in one half of the steam/water separator drums, with accompanying drum separator pressure warnings. In response, personnel triggered rapid influxes of feedwater. [[Relief valve]]s opened to relieve excess steam into a [[Surface condenser|turbine condenser]].
==== Reactor conditions priming the accident ====
When a power level of 200 MW was reattained, preparation for the experiment continued, although the power level was much lower than the prescribed 700 MW. As part of the test
The combined effect of these various actions was an extremely unstable reactor configuration. Nearly all of the 211 control rods had been extracted, and excessively high coolant flow rates meant that the water had less time to cool between trips through the core, therefore entering the reactor very close to the boiling point. Unlike other [[light-water reactor]] designs, the RBMK design at that time had a positive [[void coefficient]] of reactivity at typical fuel burnup levels. This meant that the formation of steam bubbles (voids) from boiling cooling water intensified the nuclear chain reaction owing to voids having lower [[neutron absorption]] than water. Unknown to the operators, the void coefficient was not counterbalanced by other reactivity effects in the given operating regime, meaning that any increase in boiling would produce more steam voids which further intensified the chain reaction, leading to a [[positive feedback]] loop. Given this characteristic, reactor No. 4 was now at risk of a runaway increase in its core power with nothing to restrain it. The reactor was now very sensitive to the regenerative effect of steam voids on reactor power.<ref name=insag7/>{{rp|3,14}}
=== Accident ===
==== Test execution ====
[[File:RBMK Reaktor ChNPP-4.svg|thumb|upright=2.6|Plan view of reactor No. 4 core. The number on each control rod indicates the insertion depth in centimeters one minute prior to the disaster. <br />{{Color box|#0067ce|border=darkgray}} neutron detectors (12)<br />{{Color box|#00b150|border=darkgray}} control rods (167)<br />{{Color box|#fed800|border=darkgray}} short control rods from below reactor (32)<br />{{Color box|#de1700|border=darkgray}} automatic control rods (12)<br />{{Color box|#a5b5a4|border=darkgray}} pressure tubes with fuel rods (1661)]]
At 01:23:04, the test began.<ref name=":2">{{Cite web|url=https://www.usatoday.com/story/news/world/2016/04/17/chernobyl-timeline-disaster-30th-anniversary/82899108/|title=Chernobyl: Timeline of a nuclear nightmare|last=Hjelmgaard|first=Kim|date=17 April 2016|website=USA Today|language=en|access-date=18 June 2019|archive-date=26 June 2019|archive-url=https://web.archive.org/web/20190626180550/https://www.usatoday.com/story/news/world/2016/04/17/chernobyl-timeline-disaster-30th-anniversary/82899108/|url-status=live}}</ref> Four of the eight main circulating pumps (MCP) were to be powered by voltage from the coasting turbine, while the remaining four pumps received electrical power from the grid as normal. The steam to the turbines was shut off, beginning a run-down of the turbine generator. The diesel generators started and sequentially picked up loads; the generators were to have completely picked up the MCPs' power needs by 01:23:43. As the [[momentum]] of the turbine generator decreased, so did the power it produced for the pumps. The water flow rate decreased, leading to increased formation of steam voids in the coolant flowing up through the fuel pressure tubes.<ref name="insag7"/>{{rp|8}}
==== Reactor shutdown and power excursion ====
At 01:23:40
The personnel had
[[File:Chernobyl burning-aerial view of core.jpg|thumb|upright=1.4|Steam plumes continued to be generated days after the initial explosion<ref>{{cite news |url=https://www.theguardian.com/environment/gallery/2011/apr/26/chernobyl-nuclear-disaster-in-pictures |title=Chernobyl nuclear disaster – in pictures |last=Kostin |first=Igor |author-link=Igor Kostin |date=26 April 2011 |newspaper=[[The Guardian]] |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181108184910/https://www.theguardian.com/environment/gallery/2011/apr/26/chernobyl-nuclear-disaster-in-pictures |archive-date=8 November 2018 |url-status=live }}</ref>]]
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A few seconds into the scram, a power spike occurred, and the core overheated, causing some of the [[fuel rod]]s to fracture. Some have speculated that this also blocked the control rod columns, jamming them at one-third insertion. Within three seconds the reactor output rose above 530 MW.<ref name="MedvedevZ"/>{{rp|31}}
Instruments did not register the subsequent course of events; it was reconstructed through mathematical simulation.
====
As the [[scram]] continued, the reactor output jumped to around 30,000 MW thermal, 10 times its normal operational output, the indicated last reading
This explosion ruptured further fuel channels, as well as severing most of the coolant lines feeding the reactor chamber
A second, more powerful explosion occurred about two or three seconds after the first; this explosion dispersed the damaged core and effectively terminated the [[nuclear chain reaction]]. This explosion
According to observers outside Unit 4, burning lumps of material and sparks shot into the air above the reactor. Some of them fell onto the roof of the machine hall and started a fire. About 25% of the red-hot graphite blocks and overheated material from the fuel channels was ejected. Parts of the graphite blocks and fuel channels were out of the reactor building. As a result of the damage to the building, an airflow through the core was established by the core's high temperature. The air ignited the hot graphite and started a graphite fire.<ref name="MedvedevZ"/>{{rp|32}}
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After the larger explosion, several employees at the power station went outside to get a clearer view of the extent of the damage. One such survivor, [[Individual involvement in the Chernobyl disaster#Aleksandr Yuvchenko|Alexander Yuvchenko]], said that once he stepped out and looked up towards the reactor hall, he saw a "very beautiful" laser-like beam of blue light caused by the [[ionized-air glow]] that appeared to be "flooding up into infinity".<ref name="Meyer">{{cite magazine |last1=Meyer |first1=C. M. |date=March 2007 |title=Chernobyl: what happened and why? |url=http://www.eepublishers.co.za/images/upload/Meyer%20Chernobyl%205.pdf |archive-url=https://web.archive.org/web/20131211073343/http://www.eepublishers.co.za/images/upload/Meyer%20Chernobyl%205.pdf |archive-date=11 December 2013 |magazine=Energize |location=Muldersdrift, South Africa |page=41 |issn=1818-2127}}</ref><ref name="Bond">{{cite magazine |last1=Bond |first1=Michael |title=Cheating Chernobyl |magazine=New Scientist |date=21 August 2004 |volume=183 |issue=2461 |page=46 |url=https://www.newscientist.com/article/mg18324615-300-cheating-chernobyl/ |url-access=subscription |issn=0262-4079 |access-date=5 August 2021 |archive-date=5 August 2021 |archive-url=https://web.archive.org/web/20210805065004/https://www.newscientist.com/article/mg18324615-300-cheating-chernobyl/ |url-status=live }}</ref>
=== Possible causes for the second explosion ===
There were initially several hypotheses about the nature of the second, larger explosion. One view was that the second explosion was caused by the combustion of [[hydrogen]], which had been produced either by the overheated steam-[[zircaloy|zirconium]] reaction or by the [[Syngas|reaction of red-hot graphite with steam]] that produced hydrogen and [[carbon monoxide]]. Another hypothesis, by Konstantin Checherov, published in 1998, was that the second explosion was a thermal explosion of the reactor due to the uncontrollable escape of [[fast neutron]]s caused by the complete water loss in the reactor core.<ref>{{cite book |language=ru |last=Checherov |first=K. P. |title=Development of ideas about reasons and processes of emergency on the 4th unit of Chernobyl NPP 26.04.1986 |publisher=International conference "Shelter-98" |location=Slavutich, Ukraine |date=25–27 November 1998}}</ref>
==== Fizzled nuclear explosion hypothesis ====
The force of the second explosion and the ratio of [[isotopes of xenon|xenon radioisotopes]] released after the accident led Sergei A. Pakhomov and Yuri V. Dubasov in 2009 to theorize that the second explosion could have been an extremely fast nuclear power transient resulting from core material melting in the absence of its water coolant and moderator. Pakhomov and Dubasov argued that there was no delayed supercritical increase in power but a runaway [[prompt criticality]], similar to the explosion of a [[fizzle (nuclear test)|fizzled nuclear weapon]].<ref name= Pakhomov2009/>
Their evidence came from [[Cherepovets]], a city {{convert|1000|km|mi}} northeast of Chernobyl, where physicists from the [[V.G. Khlopin Radium Institute]] measured anomalous high levels of [[xenon-135]]—a short half-life isotope—four days after the explosion. This meant that a nuclear event in the reactor may have ejected xenon to higher altitudes in the atmosphere than the later fire did, allowing widespread movement of xenon to remote locations.<ref name="DeGeer">{{cite web| title=New theory rewrites opening moments of Chernobyl disaster| url=https://phys.org/news/2017-11-theory-rewrites-moments-chernobyl-disaster.html| date=17 November 2017| publisher=Taylor and Francis| access-date=10 July 2019| archive-date=10 July 2019| archive-url=https://web.archive.org/web/20190710232127/https://phys.org/news/2017-11-theory-rewrites-moments-chernobyl-disaster.html| url-status=live}}</ref> This was an alternative to the more accepted explanation of a positive-feedback power excursion where the reactor disassembled itself by steam explosion.<ref name="insag7">{{cite web |url=http://www-pub.iaea.org/MTCD/publications/PDF/Pub913e_web.pdf |title=INSAG-7: The Chernobyl Accident: Updating of INSAG-1 |date=1992 |website=IAEA |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181020210817/https://www-pub.iaea.org/MTCD/publications/PDF/Pub913e_web.pdf |archive-date=20 October 2018 |url-status=live }}</ref><ref name= Pakhomov2009>{{cite journal |doi=10.1007/s00024-009-0029-9 |title=Estimation of Explosion Energy Yield at Chernobyl NPP Accident |year=2009 |last1=Pakhomov |first1=Sergey A. |last2=Dubasov |first2=Yuri V. |journal=Pure and Applied Geophysics |volume=167 |issue=4–5 |page=575 |bibcode=2010PApGe.167..575P|doi-access=free }}</ref>
The energy released by the second explosion, which produced the majority of the damage, was estimated by Pakhomov and Dubasov to be at 40 billion [[joule]]s, the [[TNT equivalent|equivalent]] of about 10 tons of [[TNT]].<ref name="Pakhomov2009" />
Pakhomov and Dubasov's nuclear fizzle hypothesis was examined in 2017 by Lars-Erik De Geer, Christer Persson and Henning Rodhe, who put the hypothesized fizzle event as the more probable cause of the first explosion.{{r|DeGeerNuclearJet|p=11|quote=The first explosion consisted of thermal neutron mediated nuclear explosions in one or rather a few fuel channels, which caused a jet of debris that reached an altitude of some 2500 to 3000 m. The second explosion would then have been the steam explosion most experts believe was the first one. }}<ref>{{cite web |url=http://www.sci-news.com/physics/new-study-first-seconds-chernobyl-accident-05452.html |title=New Study Rewrites First Seconds of Chernobyl Accident |date=21 November 2017 |website=Sci News |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20180612141921/http://www.sci-news.com/physics/new-study-first-seconds-chernobyl-accident-05452.html |archive-date=12 June 2018 |url-status=live }}</ref><ref name="Embury-Dennis">{{cite news |url=https://www.independent.co.uk/news/world/europe/chernobyl-disaster-cause-scientists-wrong-nuclear-power-plant-accident-ukraine-study-a8067026.html |title=Scientists might be wrong about cause of Chernobyl disaster, new study claims fresh evidence points to initial nuclear explosion rather than steam blast |first1=Tom |last1=Embury-Dennis |newspaper=[[The Independent]] |access-date=21 November 2017 |archive-url=https://web.archive.org/web/20171121164613/http://www.independent.co.uk/news/world/europe/chernobyl-disaster-cause-scientists-wrong-nuclear-power-plant-accident-ukraine-study-a8067026.html |archive-date=21 November 2017 |url-status=live }}</ref> Both analyses argue that the nuclear fizzle event, whether producing the second or first explosion, consisted of a [[prompt neutron|prompt]] chain reaction that was limited to a small portion of the reactor core, since self-disassembly occurs rapidly in fizzle events.<ref name="Pakhomov2009" /><ref name="DeGeerNuclearJet" />
=== Immediate response ===
==== Fire containment ====
[[File:Leonid Telyatnikov (1951-2004) decorated in UK.jpg|thumb|Firefighter [[Leonid Telyatnikov]] being decorated for bravery]]
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[[File:Ejected graphite from Chernobyl core.jpg|thumb|Video still image showing a [[neutron moderator|graphite moderator]] block ejected from the core]]
Anatoli Zakharov, a fireman stationed in Chernobyl
The immediate priority was to extinguish fires on the roof of the station and the area around the building containing Reactor No. 4 to protect No. 3
It was thought by some that the core fire was extinguished by a combined effort of helicopters dropping more than {{convert|5000|t|e6lbs|abbr=off}} of sand, lead, clay, and [[neutron capture|neutron-absorbing]] [[boron]] onto the burning reactor. It is now known that virtually none of these materials reached the core.<ref name="BBCContaining">{{cite news |url=http://news.bbc.co.uk/2/hi/special_report/1997/chernobyl/33005.stm |title=Special Report: 1997: Chernobyl: Containing Chernobyl? |website=BBC News |date=21 November 1997 |access-date=20 August 2011 |archive-url=https://web.archive.org/web/20110319223944/http://news.bbc.co.uk/2/hi/special_report/1997/chernobyl/33005.stm |archive-date=19 March 2011 |url-status=live }}</ref> Historians estimate that about 600 Soviet pilots risked dangerous levels of radiation to fly the thousands of flights needed to cover reactor No. 4 in this attempt to seal off radiation.<ref>{{cite web |url=http://www.rotorandwing.com/2016/04/26/chernobyl-anniversary-recalls-helo-pilots-bravery/ |title=Chernobyl Anniversary Recalls Helo Pilots' Bravery |first=James T. |last=McKenna |date=26 April 2016 |website=Rotor & Wing International |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20180705093114/http://www.rotorandwing.com/2016/04/26/chernobyl-anniversary-recalls-helo-pilots-bravery/ |archive-date=5 July 2018 |url-status=live }}</ref>
From eyewitness accounts of the firefighters involved before they died
==== Radiation levels ====
The [[ionizing radiation]] levels in the worst-hit areas of the reactor building have been estimated to be 5.6 [[roentgen (unit)|roentgens]] per second (R/s), equivalent to more than 20,000 roentgens per hour. A lethal dose is around 500 roentgens (~5 [[Gray (unit)|Gray (Gy)]] in modern radiation units) over five hours. In some areas, unprotected workers received fatal doses in less than a minute. Unfortunately, a [[dosimeter]] capable of measuring up to 1,000 R/s was buried in the rubble of a collapsed part of the building, and another one failed when turned on. Most remaining dosimeters had limits of 0.001 R/s and therefore read "off scale". The reactor crew could ascertain only that the radiation levels were somewhere above 0.001 R/s (3.6 R/h), while the true levels were vastly higher in some areas.<ref name="MedvedevZ"/>{{rp|42–50}}
Because of the inaccurate low readings, the reactor crew chief Aleksandr Akimov assumed that the reactor was intact. The evidence of pieces of graphite and reactor fuel lying around the building was ignored, and the readings of another dosimeter brought in by 04:30 were dismissed under the assumption that the new dosimeter must have been defective.<ref name="MedvedevZ"/>{{rp|42–50}} Akimov stayed in the reactor building until morning, sending members of his crew to try to pump water into the reactor. None of them wore any protective gear. Most, including Akimov, died from radiation exposure within three weeks.<ref name=MedvedevG>{{Cite book| last=Medvedev| first=Grigori| title=The Truth About Chernobyl |publisher=VAAP |year=1989 |isbn=978-2-226-04031-2 |edition=Hardcover. First American edition published by Basic Books in 1991 |title-link=The Truth About Chernobyl}}</ref><ref name=MedvedevGweb>{{cite web| first=Grigori| last=Medvedev| url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a335076.pdf| title=The Truth About Chernobyl| access-date=18 July 2019| archive-date=5 July 2019| archive-url=https://web.archive.org/web/20190705081449/https://apps.dtic.mil/dtic/tr/fulltext/u2/a335076.pdf| url-status=live}}</ref>{{rp|247–248}}
=== Accident investigation ===
{{Main|Investigations into the Chernobyl disaster}}
The [[IAEA]] had created the [[International Nuclear Safety Group|International Nuclear Safety Advisory Group]] (INSAG) in 1985.<ref>"History of the International Atomic Energy Agency", IAEA, Vienna (1997).</ref> INSAG produced two significant reports on Chernobyl: INSAG-1 in 1986, and a revised report, INSAG-7, in 1992. According to INSAG-1, the main cause of the accident was the operators' actions, but according to INSAG-7, the main cause was the reactor's design.<ref name="insag7"/>{{rp|24}}<ref>{{cite book |chapter-url=http://www.insc.anl.gov/neisb/neisb4/NEISB_3.3.A1.html |chapter=Chernobyl (Chornobyl) Nuclear Power Plant |title=NEI Source Book |edition=4th |publisher=Nuclear Energy Institute |access-date=31 July 2010 |url-status=dead |archive-url=https://timetravel.mementoweb.org/memento/2011/http://www.insc.anl.gov/neisb/neisb4/NEISB_3.3.A1.html |archive-date=2 July 2016 }}</ref> Both reports identified an inadequate "safety culture" (INSAG-1 coined the term) at all managerial and operational levels as a major underlying factor.<ref name="insag7"/>{{rp|21,24}}
== Crisis management ==
=== Evacuation ===
[[File:View of Chernobyl taken from Pripyat zoomed.JPG|thumb|[[Pripyat]] with the [[Chernobyl Nuclear Power Plant]] in the distance]]
The nearby city of Pripyat was not immediately evacuated
[[Valentyna Shevchenko (politician)|Valentyna Shevchenko]], then Chairwoman of the Presidium of [[Verkhovna Rada]] of the Ukrainian SSR, said that Ukraine's acting Minister of Internal Affairs [[Vasyl Durdynets]] phoned her at work at 09:00 to report current affairs; only at the end of the conversation did he add that there had been a fire at the Chernobyl nuclear power plant, but it was extinguished and everything was fine. When Shevchenko asked "How are the people?", he replied that there was nothing to be concerned about: "Some are celebrating a wedding, others are gardening, and others are fishing in the [[Pripyat River]]".<ref name="shevchenko"/>
Line 157 ⟶ 168:
Shevchenko then spoke by telephone to [[Volodymyr Shcherbytsky]], [[General Secretary of the Communist Party of Ukraine]] and ''de facto'' head of state, who said he anticipated a delegation of the state commission headed by [[Boris Shcherbina]], the deputy chairman of the [[Government of the Soviet Union|Council of Ministers of the USSR]].<ref name="shevchenko"/>
[[File:Chernobyl BW 2019 G28.jpg|thumb|Ruins of abandoned house in Chernobyl
A commission was established later in the day to investigate the accident. It was headed by [[Valery Legasov]], First Deputy Director of the Kurchatov Institute of Atomic Energy, and included leading nuclear specialist [[Evgeny Velikhov]], hydro-meteorologist [[Yuri Izrael]], radiologist Leonid Ilyin, and others. They flew to [[Boryspil International Airport]] and arrived at the power plant in the evening of 26 April.<ref name="shevchenko"/> By that time two people had already died and 52 were hospitalized. The delegation soon had ample evidence that the reactor was destroyed and extremely high levels of radiation had caused a number of cases of radiation exposure. In the early daylight hours of 27 April, they ordered the evacuation of Pripyat
{{Listen|filename = Pripyat 1986.ogg|title = Pripyat evacuation broadcast|description = Russian language announcement}}
{{blockquote|For the attention of the residents of Pripyat! The City Council informs you that due to the accident at Chernobyl Power Station in the city of Pripyat the radioactive conditions in the vicinity are deteriorating. The Communist Party, its officials and the armed forces are taking necessary steps to combat this. Nevertheless, with the view to keep people as safe and healthy as possible, the children being top priority, we need to temporarily evacuate the citizens in the nearest towns of Kiev region. For these reasons, starting from 27 April 1986, 14:00 each apartment block will be able to have a bus at its disposal, supervised by the police and the city officials. It is highly advisable to take your documents, some vital personal belongings and a certain amount of food, just in case, with you. The senior executives of public and industrial facilities of the city has decided on the list of employees needed to stay in Pripyat to maintain these facilities in a good working order. All the houses will be guarded by the police during the evacuation period. Comrades, leaving your residences temporarily please make sure you have turned off the lights, electrical equipment and water and shut the windows. Please keep calm and orderly in the process of this short-term evacuation.<ref name="pripyat evacuation announcement">{{cite episode|title=Meltdown in Chernobyl|series=Seconds From Disaster|series-link=Seconds From Disaster|credits=Sahota, M. (dir).; Smith, A. (nar).; Lanning, G. (prod).; Joyce, C. (ed).|network=[[National Geographic Channel]]|date=17 August 2004|season=1|number=7}}</ref>}}
[[File:P9060463 (11383823203).jpg|thumb|Abandoned objects in the evacuation zone]]
To expedite the evacuation, residents were told to bring only what was necessary, and that they would remain evacuated for approximately three days. As a result, most personal belongings were left behind, and residents were only allowed to recover certain items after months had passed. By 15:00, 53,000 people were evacuated to
The surveying and detection of isolated fallout hotspots outside this zone over the following year eventually resulted in 135,000 long-term evacuees in total
=== Official announcement ===
[[File:SPOT-1-1986-05-01-Tchernobyl-PAN.jpg|thumb|upright=1.6|Picture taken by French satellite [[SPOT (satellite)|SPOT-1]] on 1 May 1986]]
Evacuation began one and a half days before the accident was publicly acknowledged by the Soviet Union. In the morning of 28 April, radiation levels set off alarms at the [[Forsmark Nuclear Power Plant]] in [[Sweden]],<ref>{{cite news |title=LIVING WITH CATASTROPHE |date=10 December 1995 |url=https://www.independent.co.uk/arts-entertainment/living-with-catastrophe-1524915.html |website=[[The Independent]] |access-date=8 February 2019 |archive-url=https://web.archive.org/web/20190423140441/https://www.independent.co.uk/arts-entertainment/living-with-catastrophe-1524915.html |archive-date=23 April 2019 |url-status=live }}</ref><ref name="Sveriges"/> over {{convert|1000|km}} from the Chernobyl Plant. Workers at Forsmark reported the case to the [[Swedish Radiation Safety Authority]], which determined that the radiation had originated elsewhere. That day, the Swedish government contacted the Soviet government to inquire about whether there had been a nuclear accident in the Soviet Union. The Soviets initially denied it
At first, the Soviets only conceded that a minor accident had occurred, but once they began evacuating more than 100,000 people, the full scale of the situation was realized by the global community.<ref>{{Cite journal|last=Baverstock|first=K.|date=26 April 2011|title=Chernobyl 25 years on|journal=BMJ|volume=342|issue=apr26 1|page=d2443|doi=10.1136/bmj.d2443|pmid=21521731|s2cid=12917536|issn=0959-8138}}</ref> At 21:02 the evening of 28 April, a 20-second announcement was read in the TV news programme ''[[Vremya]]'': "There has been an accident at the Chernobyl Nuclear Power Plant. One of the nuclear reactors was damaged. The effects of the accident are being remedied. Assistance has been provided for any affected people. An investigative commission has been set up."<ref name="GalleryTimeline">{{cite web |url=http://chernobylgallery.com/chernobyl-disaster/timeline/ |title=Timeline: A chronology of events surrounding the Chernobyl nuclear disaster |website=The Chernobyl Gallery |access-date=8 November 2018 |date=15 February 2013 |archive-url=https://web.archive.org/web/20150318013918/http://chernobylgallery.com/chernobyl-disaster/timeline/ |archive-date=18 March 2015 |url-status=live|quote=''28 April – Monday 09:30'' – Staff at the Forsmark Nuclear Power Plant, Sweden, detect a dangerous surge in radioactivity. Initially picked up when a routine check reveals that the soles shoes worn by a radiological safety engineer at the plant were radioactive. ''[28 April – Monday] 21:02'' – Moscow TV news announce that an accident has occurred at the Chornobyl Nuclear Power Plant.[...] ''[28 April – Monday] 23:00'' – A Danish nuclear research laboratory announces that an MCA (maximum credible accident) has occurred in the Chernobyl nuclear reactor. They mention a complete meltdown of one of the reactors and that all radioactivity has been released. }}</ref><ref name="vremya">{{YouTube|sC7n_QgJRks|Video footage of Chernobyl disaster on 28 April}} {{in lang|ru}}.</ref>
This was
Around the same time, [[ABC News (United States)|ABC News]] released its report about the disaster.<ref>{{cite web |url=http://www.istpravda.com.ua/videos/2011/04/25/36966/ |title=1986: американський ТБ-сюжет про Чорнобиль. Порівняйте з радянським |work=Історична правда |date=25 April 2011 |language=uk |access-date=2 May 2011 |archive-url=https://web.archive.org/web/20110502133614/http://www.istpravda.com.ua/videos/2011/04/25/36966/ |archive-date=2 May 2011 |url-status=live }}</ref> Shevchenko was the first of the Ukrainian state top officials to arrive at the disaster site early on 28 April.
There was a notification from Moscow that there was no reason to postpone the 1 May [[International Workers' Day]] celebrations in Kiev.
Several buildings in Pripyat were
=== Core meltdown risk mitigation ===
[[File:Chernobyl lava flow.jpg|thumb|Chernobyl lava-like [[corium (nuclear reactor)|corium]], formed by fuel-containing mass, flowed into the basement of the plant.<ref name=Lava1/>]]
[[File:Levels of radioactivity in the lava under the Chernobyl number four reactor 1986.svg|thumb|upright=2.4|Extremely high levels of radioactivity in the lava under the Chernobyl number four reactor in 1986]]
====Bubbler pools====
Two floors of bubbler pools beneath the reactor served as a large water reservoir for the emergency cooling pumps and as a pressure suppression system capable of condensing steam in case of a small broken steam pipe; the third floor above them, below the reactor, served as a steam tunnel. The steam released by a broken pipe was supposed to enter the steam tunnel and be led into the pools to bubble through a layer of water. After the disaster, the pools and the basement were flooded because of ruptured cooling water pipes and accumulated firefighting water.
The smoldering graphite, fuel and other material, at more than {{convert|1200|C|F}},<ref name=lava2>{{cite journal |doi=10.1134/S1087659609020126 |title=Behavior of melts in the UO2-SiO2 system in the liquid-liquid phase separation region |year=2009 |last1=Petrov |first1=Yu. B. |last2=Udalov |first2=Yu. P. |last3=Subrt |first3=J. |last4=Bakardjieva |first4=S. |last5=Sazavsky |first5=P. |last6=Kiselova |first6=M. |last7=Selucky |first7=P. |last8=Bezdicka |first8=P. |last9=Jorneau |first9=C. |last10=Piluso |first10=P. |journal=Glass Physics and Chemistry |volume=35 |issue=2 |pages=199–204|s2cid=135616447 }}</ref> started to burn through the reactor floor and mixed with molten concrete from the reactor lining, creating [[corium (nuclear reactor)|corium]], a radioactive semi-liquid material comparable to [[lava]].<ref name=Lava1>{{cite journal |doi=10.1134/S1066362208050131 |title=Formation and spread of Chernobyl lavas |year=2009 |last1=Bogatov |first1=S. A. |last2=Borovoi |first2=A. A. |last3=Lagunenko |first3=A. S. |last4=Pazukhin |first4=E. M. |last5=Strizhov |first5=V. F. |last6=Khvoshchinskii |first6=V. A. |journal=Radiochemistry |volume=50 |issue=6 |pages=650–654|s2cid=95752280 }}</ref><ref name=lava3>{{Cite news |last1=Journeau |first1=Christophe |last2=Boccaccio|first2=Eric|last3=Jégou|first3=Claude |last4=Piluso|first4=Pascal |last5=Cognet|first5=Gérard |title=Flow and Solidification of Corium in the VULCANO Facility |publisher=Commissariat à l'énergie atomique et aux énergies alternatives |series=Engineering case studies online|year=2001 |oclc=884784975|citeseerx=10.1.1.689.108 }}</ref> It was feared that if this mixture melted through the floor into the pool of water, the resulting steam production would further contaminate the area or even cause
Unaware of this
====Foundation protection measures====
The government commission was concerned that the molten core would burn into the earth and contaminate groundwater
As an alternative, subway builders and [[coal miner]]s were deployed to excavate a tunnel below the reactor to make room for a cooling system. The final makeshift design for the cooling system was to incorporate a coiled formation of pipes cooled with water and covered on top with a thin thermally conductive graphite layer. The graphite layer
=== Site cleanup ===
====Debris removal====
In the months after the explosion, attention turned to removing the radioactive debris from the roof.<ref name="robotsroof">{{Cite web |last=Anderson |first=Christopher |title=Soviet Official Admits That Robots Couldn't Handle Chernobyl Cleanup |url=https://www.the-scientist.com/news/soviet-official-admits-that-robots-couldnt-handle-chernobyl-cleanup-61583 |work=The Scientist |date=January 2019 |access-date=1 June 2019 |archive-url=https://web.archive.org/web/20190410204859/https://www.the-scientist.com/news/soviet-official-admits-that-robots-couldnt-handle-chernobyl-cleanup-61583 |archive-date=10 April 2019 |url-status=live }}</ref> While the worst of the radioactive debris had remained inside what was left of the reactor,
Consequently, the most highly radioactive materials were shoveled by [[Chernobyl liquidators]] from the military, wearing
====Construction of the sarcophagus====
{{main|Chernobyl Nuclear Power Plant sarcophagus}}
[[File:Chernobylreactor 1.jpg|thumb|upright=1.2|No. 4 reactor site in 2006 showing the [[Chernobyl Nuclear Power Plant sarcophagus|sarcophagus containment structure]]; Reactor No. 3 is to the left of the smoke stack]]
With the extinguishing of the open air reactor fire, the next step was to prevent the spread of contamination
The solution chosen was to enclose the wrecked reactor by the construction of a huge composite steel and concrete shelter, which became known as the "Sarcophagus". It had to be erected quickly and within the constraints of high levels of ambient gamma radiation. The design started on 20 May 1986, 24 days after the disaster, and construction was from June to late November.<ref>Ebel, Robert E.; Center for Strategic and International Studies (1994). ''Chernobyl and its aftermath: a chronology of events'' (1994 ed.). CSIS. {{ISBN|978-0-89206-302-4}}.</ref>
The construction workers had to be protected from radiation, and techniques such as crane drivers working from lead-lined control cabins were employed. The construction work included erecting walls around the perimeter, clearing and surface concreting the surrounding ground to remove sources of radiation and to allow access for large construction machinery, constructing a thick radiation shielding wall to protect the workers in reactor No. 3, fabricating a high-rise buttress to strengthen
====Investigations of the reactor condition====
During the construction of the sarcophagus, a scientific team, as part of an investigation dubbed "Complex Expedition", re-entered the reactor to locate and contain nuclear fuel to prevent another explosion. These scientists manually collected cold fuel rods, but great heat was still emanating from the core. Rates of radiation in different parts of the building were monitored by drilling holes into the reactor and inserting long metal detector tubes. The scientists were exposed to high levels of radiation
In December 1986, after six months of investigation, the team discovered with the help of a remote camera that an intensely radioactive mass more than {{convert|2|m}} wide had formed in the basement of Unit Four. The mass was called "[[Elephant's Foot (Chernobyl)|the elephant's foot]]" for its wrinkled appearance.<ref>{{cite magazine |url=http://nautil.us/blog/chernobyls-hot-mess-the-elephants-foot-is-still-lethal |title=Chernobyl's Hot Mess, 'the Elephant's Foot', Is Still Lethal |first=Kyle |last=Hill |date=4 December 2013 |magazine=[[Nautilus (science magazine)|Nautilus]] |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181115173340/http://nautil.us/blog/chernobyls-hot-mess-the-elephants-foot-is-still-lethal |archive-date=15 November 2018 |url-status=live }}</ref> It was composed of melted sand, concrete, and a large amount of nuclear fuel that had escaped from the reactor. The concrete beneath the reactor was steaming hot, and was breached by now-solidified lava and spectacular unknown crystalline forms termed [[chernobylite]]. It was concluded that there was no further risk of explosion.<ref name="BBCContaining"/>
Line 228 ⟶ 239:
===Area cleanup===
[[File:Médailles liquidateurs.jpg|thumb|upright=1.2|Soviet badge and medal awarded to [[Chernobyl liquidators]]]]
[[File:20110426-IWHO-22.jpg|thumb|Portraits of deceased [[Chernobyl liquidators]] used for an [[anti-nuclear]] power protest in [[Geneva]]]]
The official contaminated zones saw a massive clean-up effort lasting seven months.<ref name="MarplesSocialImpact"/>{{rp|177–183}} The official reason for such early,
Helicopters regularly sprayed large areas of contaminated land with "Barda", a sticky polymerizing fluid, designed to entrap radioactive dust.<ref>{{cite web |last=Belyaev |first=I. |title=Чернобыль – вахта смерти |trans-title=Chernobyl – Watch of Death |url=https://elib.biblioatom.ru/text/belyaev_chernobyl-vahta-smerti_2009/p58/?hl=%D0%B1%D0%B0%D1%80%D0%B4%D0%B0 |accessdate=2024-05-18 |work=Biblioatom |publisher=Rosatom |language=Ru}}</ref> Although a number of radioactive emergency vehicles were buried in trenches, many of the vehicles used by the liquidators still remained, as of 2018, parked in a field in the Chernobyl area. Scavengers have removed many functioning, but highly radioactive, parts.<ref>{{cite news |url=http://news.bbc.co.uk/2/shared/spl/hi/pop_ups/06/in_pictures_chernobyl0s_silent_graveyards_/html/1.stm |title=Chernobyl's silent graveyards |date=20 April 2006 |website=BBC News |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181105043521/http://news.bbc.co.uk/2/shared/spl/hi/pop_ups/06/in_pictures_chernobyl0s_silent_graveyards_/html/1.stm |archive-date=5 November 2018 |url-status=live }}</ref>
== Site remediation ==
Questions arose about the future of the plant and its fate. All work on the unfinished reactors No. 5 and No. 6 was halted three years later. The damaged reactor was sealed off and {{convert|200|m3|yd3|-1|sp=us}} of concrete was placed between the disaster site and the operational buildings. The [[Government of Ukraine|Ukrainian government]] allowed the three remaining reactors to continue operating because of an energy shortage.
In October 1991, a fire occurred in the turbine building of reactor No. 2;<ref>{{cite web |url=https://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/1993/in93071.html |title=Information Notice No. 93–71: Fire At Chernobyl Unit 2 |date=13 September 1993 |website=Nuclear Regulatory Commission |access-date=20 August 2011 |archive-url=https://web.archive.org/web/20120112040027/http://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/1993/in93071.html |archive-date=12 January 2012 |url-status=live }}</ref> the authorities subsequently declared the reactor damaged beyond repair, and it was taken offline. Reactor No. 1 was decommissioned in November 1996 as part of a deal between the Ukrainian government and international organizations such as the IAEA to end operations at the plant. On 15 December 2000, then-President [[Leonid Kuchma]] personally turned off reactor No. 3 in an official ceremony, shutting down the entire site.<ref>{{cite web |url=https://pris.iaea.org/pris/CountryStatistics/ReactorDetails.aspx?current=575 |title=Chernobyl-3 |website=IAEA Power Reactor Information System |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181108230003/https://pris.iaea.org/pris/CountryStatistics/ReactorDetails.aspx?current=575 |archive-date=8 November 2018 |url-status=live }} Site polled in May 2008 reports shutdown for units 1, 2, 3 and 4 respectively at 30 November 1996, 11 October 1991, 15 December 2000 and 26 April 1986.</ref>
=== No. 4 reactor confinement ===
{{further|Chernobyl New Safe Confinement}}
[[File:NSC-Oct-2017.jpg|thumb|[[Chernobyl New Safe Confinement]] in 2017]]
Soon after the accident, the reactor building was quickly encased by a mammoth concrete sarcophagus. Crane operators worked blindly from inside lead-lined cabins taking instructions from distant radio observers, while gargantuan-sized pieces of concrete were moved to the site on custom-made vehicles. The purpose of the sarcophagus was to stop any further release of radioactive particles into the atmosphere, isolate the exposed core from the weather and provide safety for the continued operations of adjacent reactors one through three.<ref name="chornobyl.in.ua">{{cite web |url=http://www.chornobyl.in.ua/en/shelter.htm |title="Shelter" object |website=Chernobyl, Pripyat, the Chernobyl nuclear power plant and the exclusion zone |access-date=8 May 2012 |archive-url=https://web.archive.org/web/20110722200757/http://www.chornobyl.in.ua/en/shelter.htm |archive-date=22 July 2011 |url-status=live|quote=The bulk of work that had been implemented in order to eliminate the consequences of the accident and minimalize the escape of radionuclides into the environment was to construct a protective shell over the destroyed reactor at Chernobyl.[...] work on the construction of a protective shell was the most important, extremely dangerous and risky. The protective shell, which was named the '''«Shelter»''' object, was created in a very short period of time—six months. [...] Construction of the '''"Shelter"''' object began after mid-May 1986. The State Commission decided on the long-term conservation of the fourth unit of the Chernobyl Nuclear Power Plant in order to prevent the release of radionuclides into the environment and to reduce the influence of penetrating radiation at the Chernobyl Nuclear Power Plant site. }}</ref>
In 1997, the international [[Chernobyl Shelter Fund]] was founded to design and build a more permanent cover for the unstable and short-lived sarcophagus. It received €864 million from international donors in 2011 and was managed by the [[European Bank for Reconstruction and Development]] (EBRD).<ref>{{Cite web |title=Chernobyl {{!}} Chernobyl Accident {{!}} Chernobyl Disaster – World Nuclear Association |url=https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident.aspx |access-date=18 April 2022 |website=world-nuclear.org}}</ref> The new shelter was named the [[New Safe Confinement]] and construction began in 2010. It is a metal arch {{convert|105|m}} high and spanning {{convert|257|m}} built on rails adjacent to the reactor No. 4 building so that it could be slid over the top of the existing sarcophagus. The New Safe Confinement was completed in 2016 and slid into place over the sarcophagus on 29 November.<ref>{{Cite news |url=https://www.theguardian.com/world/2016/nov/29/chernobyl-nuclear-disaster-site-covered-with-shelter-prevent-radiation-leaks-ukraine |title=Chernobyl disaster site enclosed by shelter to prevent radiation leaks |last=Walker |first=Shaun |date=29 November 2016 |newspaper=The Guardian |issn=0261-3077 |access-date=23 December 2016 |archive-url=https://web.archive.org/web/20161222104254/https://www.theguardian.com/world/2016/nov/29/chernobyl-nuclear-disaster-site-covered-with-shelter-prevent-radiation-leaks-ukraine |archive-date=22 December 2016 |url-status=live }}</ref> Unlike the original sarcophagus, the New Safe Confinement is designed to allow the reactor to be safely dismantled using remotely operated equipment.
=== Waste management ===
Used fuel from units 1–3 was stored in the units' cooling ponds, and in an interim spent fuel storage facility pond, ISF-1, which now holds most of the spent fuel from units 1–3, allowing those reactors to be decommissioned under less restrictive conditions. Approximately 50 of the fuel assemblies from units 1 and 2 were damaged and required special handling. Moving fuel to ISF-1 was thus carried out in three stages: fuel from unit 3 was moved first, then all undamaged fuel from units 1 and 2, and finally the damaged fuel from units 1 and 2. Fuel transfers to ISF-1 were completed in June 2016.<ref>{{cite news |url=https://world-nuclear-news.org/Articles/Chernobyl-units-1-3-now-clear-of-damaged-fuel |title=Chernobyl units 1–3 now clear of damaged fuel |date=7 June 2016 |work=[[World Nuclear Association|World Nuclear News]] |access-date=30 June 2019 |archive-date=30 June 2019 |archive-url=https://web.archive.org/web/20190630223325/http://world-nuclear-news.org/Articles/Chernobyl-units-1-3-now-clear-of-damaged-fuel |url-status=live }}</ref>
A need for larger, longer-term [[radioactive waste]] management at the site is to be fulfilled by a new facility designated ISF-2. This facility is to serve as dry storage for used fuel assemblies from units 1–3 and other operational wastes, as well as material from decommissioning units 1–3.
A contract was signed in 1999 with Areva NP ([[Framatome]]) for construction of ISF-2. In 2003, after a significant part of the storage structures had been built, technical deficiencies in the design concept became apparent. In 2007, Areva withdrew and [[Holtec International]] was contracted for a new design and construction of ISF-2. The new design was approved in 2010, work started in 2011, and construction was completed in August 2017.<ref>{{cite news |url=https://world-nuclear-news.org/Articles/Holtec-clear-to-start-testing-ISF2-at-Chernobyl |title=Holtec clear to start testing ISF2 at Chernobyl |date=4 August 2017 |work=[[World Nuclear Association|World Nuclear News]] |access-date=17 September 2019 |archive-date=18 September 2019 |archive-url=https://web.archive.org/web/20190918070303/http://world-nuclear-news.org/Articles/Holtec-clear-to-start-testing-ISF2-at-Chernobyl |url-status=live }}</ref>
ISF-2 is the world's largest nuclear fuel storage facility, expected to hold more than 21,000 fuel assemblies for at least 100 years. The project includes a processing facility able to cut the RBMK fuel assemblies and to place the material in canisters, to be filled with [[inert gas]] and welded shut. The canisters are then to be transported to [[dry cask storage|dry storage vaults]], where the fuel containers will be enclosed for up to 100 years. Expected processing capacity is 2,500 fuel assemblies per year.<ref name="WNA-Chernobyl"/>
==== Fuel-containing materials ====
The radioactive material consists of core fragments, dust, and lava-like "fuel containing materials" (FCM)—also called "[[Corium (nuclear reactor)|corium]]"—that flowed through the wrecked reactor building before hardening into a [[ceramic]] form.
Three different lavas are present in the basement of the reactor building: black, brown, and a [[porous]] ceramic. The lava materials are [[silicate glass]]es with [[inclusion (mineral)|inclusions]] of other materials within them. The porous lava is brown lava that dropped into water and thus cooled rapidly. It is unclear how long the ceramic form will retard the release of radioactivity. From 1997 to 2002, a series of published papers suggested that the self-irradiation of the lava would convert all {{convert|1200|t|LT ST}} into a submicrometre and mobile powder within a few weeks.<ref>{{cite journal |first1=V. |last1=Baryakhtar |first2=V. |last2=Gonchar |first3=A. |last3=Zhidkov |first4=V. |last4=Zhidkov |title=Radiation damages and self-sputtering of high-radioactive dielectrics: spontaneous emission of submicronic dust particles |journal=Condensed Matter Physics |year=2002 |volume=5 |number=3{31} |pages=449–471 |url=http://www.icmp.lviv.ua/journal/zbirnyk.31/005/art05.pdf |doi=10.5488/cmp.5.3.449 |bibcode=2002CMPh....5..449B |access-date=30 October 2013 |archive-url=https://web.archive.org/web/20131101175848/http://www.icmp.lviv.ua/journal/zbirnyk.31/005/art05.pdf |archive-date=1 November 2013 |url-status=live |doi-access=free }}</ref>
It has been reported that the degradation of the lava is likely to be a slow, gradual process.<ref name="Borovoi2006">{{cite journal |doi=10.1007/s10512-006-0079-3 |title=Nuclear fuel in the shelter |year=2006 |last1=Borovoi |first1=A. A. |journal=Atomic Energy |volume=100 |issue=4 |page=249|s2cid=97015862 }}</ref> The same paper states that the loss of [[uranium]] from the wrecked reactor is only {{convert|10|kg|lb|abbr=on}} per year; this low rate of uranium leaching suggests that the lava is resisting its environment.<ref name="Borovoi2006"/> The paper also states that when the shelter is improved, the leaching rate of the lava will decrease.<ref name="Borovoi2006"/> As of 2021, some fuel had already degraded significantly. The famous elephant's foot, which originally was so hard that it required the use of an armor piercing [[AK-47]] round to remove a chunk, had softened to a texture similar to sand.<ref name=":3" /><ref name="Higginbotham">{{Cite book|last=Higginbotham|first=Adam|title=[[Midnight in Chernobyl|Midnight in Chernobyl: The Untold Story of the World's Greatest Nuclear Disaster]]|publisher=Random House|year=2019|isbn=978-1-4735-4082-8|page=340|quote=The substance proved too hard for a drill mounted on a motorized trolley, ... Finally, a police marksman arrived and shot a fragment of the surface away with a rifle. The sample revealed that the Elephant's Foot was a solidified mass of silicon dioxide, titanium, zirconium, magnesium, and uranium ...}}</ref>
Prior to the completion of the New Safe Confinement building, rainwater acted as a [[neutron moderator]], triggering increased fission in the remaining materials, risking criticality. [[Gadolinium nitrate]] solution was used to quench neutrons to slow the fission. Even after completion of the building, fission reactions may be increasing; scientists are working to understand the cause and risks. While neutron activity has declined across most of the destroyed fuel, from 2017 until late 2020 a doubling in neutron density was recorded in the sub-reactor space, before levelling off in early 2021. This indicated increasing levels of fission as water levels dropped, the opposite of what had been expected, and atypical compared to other fuel-containing areas. The fluctuations have led to fears that a self-sustaining reaction could be created, which would likely spread more radioactive dust and debris throughout the New Safe Confinement, making future cleanup even more difficult. Potential solutions include using a robot to drill into the fuel and insert boron carbide control rods.<ref name=":3">{{cite news|last1=Stone|first1=Richard|date=5 May 2021|title='It's like the embers in a barbecue pit.' Nuclear reactions are smoldering again at Chernobyl|work=[[Science (journal)|Science]]|publisher=[[American Association for the Advancement of Science]]|url=https://www.science.org/content/article/nuclear-reactions-reawaken-chernobyl-reactor|access-date=10 May 2021|archive-date=10 May 2021|archive-url=https://web.archive.org/web/20210510004508/https://www.sciencemag.org/news/2021/05/nuclear-reactions-reawaken-chernobyl-reactor|url-status=live}}</ref> In early 2021, a ChNPP press release stated that the observed increase in neutron densities had leveled off since the beginning of that year.
=== Exclusion zone ===
{{Further|Chernobyl Exclusion Zone}}
[[File:Map of Chernobyl Exclusion Zone.svg|thumb|upright=2.6|A map of the Exclusion Zone]]
[[File:Checkpoint ditkatky chernobyl zone.JPG|thumb|The entrance to the [[Chernobyl Exclusion Zone|zone of alienation]] around Chernobyl]]
The Exclusion Zone was originally an area with a radius of {{convert|30|km}} in all directions from the plant, but was subsequently greatly enlarged to include an area measuring approximately {{convert|2600|km2|abbr=on}}, officially called the "[[Chernobyl Exclusion Zone|zone of alienation]]". The area has largely reverted to forest and was overrun by wildlife due to the lack of human competition for space and resources.<ref name="Telegraph2016">{{cite news |last1=Oliphant |first1=Roland |title=30 years after Chernobyl disaster, wildlife is flourishing in radioactive wasteland |url=https://www.telegraph.co.uk/news/2016/04/23/wildlife-returns-to-radioactive-wasteland-of-chernobyl/ |access-date=27 April 2016 |newspaper=The Daily Telegraph |date=24 April 2016 |archive-url=https://web.archive.org/web/20160427011132/http://www.telegraph.co.uk/news/2016/04/23/wildlife-returns-to-radioactive-wasteland-of-chernobyl/ |archive-date=27 April 2016 |url-status=live }}</ref>
Mass media sources have provided generalized estimates for when the Zone could be considered [[Habitability|habitable]] again. These informal estimates have ranged<ref name="csmonitor" /> from approximately 300 years<ref>,{{cite news |title=Chornobyl by the numbers |url=https://www.cbc.ca/news/world/chornobyl-by-the-numbers-1.1097000 |access-date=9 July 2020 |work=CBC |date=2011 |archive-date=17 September 2020 |archive-url=https://web.archive.org/web/20200917161615/https://www.cbc.ca/news/world/chornobyl-by-the-numbers-1.1097000 |url-status=live }}</ref> to multiples of 20,000 years,<ref name="csmonitor">{{cite news |title=Chernobyl will be unhabitable for at least 3,000 years, say nuclear experts |url=https://www.csmonitor.com/World/Global-News/2016/0424/Chernobyl-will-be-unhabitable-for-at-least-3-000-years-say-nuclear-experts |access-date=10 May 2020 |work=Christian Science Monitor |date=24 April 2016 |archive-date=26 April 2020 |archive-url=https://web.archive.org/web/20200426171834/https://www.csmonitor.com/World/Global-News/2016/0424/Chernobyl-will-be-unhabitable-for-at-least-3-000-years-say-nuclear-experts |url-status=live }}</ref> referring to the half-life of Plutonium-239 which contaminates the central portion of the Zone.
In the years following the disaster, residents known as ''[[samosely]]'' illegally returned to their abandoned homes. Most people are retired and survive mainly from farming and packages delivered by visitors.<ref>{{Cite web |date=23 April 2016 |title=What life is like in the shadows of Chernobyl |url=https://www.abc.net.au/news/2016-04-23/living-in-the-shadows-of-chernobyl/7342368 |access-date=1 May 2022 |website=ABC News |language=en-AU}}</ref><ref>{{Cite web |author1=Turner |first=Ben |date=3 February 2022 |title=What is the Chernobyl Exclusion Zone? |url=https://www.livescience.com/chernobyl-exclusion-zone |access-date=1 May 2022 |website=livescience.com |language=en}}</ref> {{As of|2016}}, 187 locals had returned to the zone and were living permanently there.<ref name="Telegraph2016"/>
In 2011, Ukraine opened the sealed zone around the Chernobyl reactor to tourists.<ref>{{cite news |url=http://www.foxnews.com/world/2010/12/13/ukraine-open-chernobyl-area-tourists-1172479551/ |title=Ukraine to Open Chernobyl Area to Tourists in 2011 |agency=Associated Press |date=13 December 2010 |website=Fox News |access-date=2 March 2012 |archive-url=https://web.archive.org/web/20120308011104/http://www.foxnews.com/world/2010/12/13/ukraine-open-chernobyl-area-tourists-1172479551/ |archive-date=8 March 2012 |url-status=live }}</ref><ref>{{cite news |url=http://www.travelsnitch.org/categories/features/tours-of-chernobyl-sealed-zone-officially-begin/ |title=Tours of Chernobyl sealed zone officially begin |date=18 March 2011 |website=TravelSnitch |archive-url=https://web.archive.org/web/20130430053527/http://www.travelsnitch.org/categories/features/tours-of-chernobyl-sealed-zone-officially-begin/ |url-status=dead |archive-date=30 April 2013}}</ref><ref name="Distillations">{{cite magazine |last1=Boyle |first1=Rebecca |title=Greetings from Isotopia |magazine=Distillations |date=2017 |volume=3 |issue=3 |pages=26–35 |url=https://www.sciencehistory.org/distillations/magazine/greetings-from-isotopia |access-date=19 June 2018 |archive-url=https://web.archive.org/web/20180615004504/https://www.sciencehistory.org/distillations/magazine/greetings-from-isotopia |archive-date=15 June 2018 |url-status=live }}</ref><ref name="Digges">{{cite news |last1=Digges |first1=Charles |title=Reflections of a Chernobyl liquidator – the way it was and the way it will be |url=http://bellona.org/news/nuclear-issues/accidents-and-incidents/2006-10-reflections-of-a-chernobyl-liquidator-the-way-it-was-and-the-way-it-will-be |access-date=20 June 2018 |work=Bellona |date=4 October 2006 |archive-url=https://web.archive.org/web/20180620181614/http://bellona.org/news/nuclear-issues/accidents-and-incidents/2006-10-reflections-of-a-chernobyl-liquidator-the-way-it-was-and-the-way-it-will-be |archive-date=20 June 2018 |url-status=live }}</ref>
==== Forest fire concerns ====
{{see also|Polesie State Radioecological Reserve}}
During the dry season, [[Wildfire|forest fires]] are a perennial concern in areas contaminated by radioactive material. Dry conditions and build-up of debris make the forests a ripe breeding ground for wildfires.<ref>{{Cite journal|last1=Evangeliou|first1=Nikolaos|last2=Balkanski|first2=Yves|last3=Cozic|first3=Anne|last4=Hao|first4=Wei Min|last5=Møller|first5=Anders Pape|date=December 2014|title=Wildfires in Chernobyl-contaminated forests and risks to the population and the environment: A new nuclear disaster about to happen?|journal=Environment International|volume=73|pages=346–358|doi=10.1016/j.envint.2014.08.012|pmid=25222299|issn=0160-4120|doi-access=free|bibcode=2014EnInt..73..346E }}</ref> Depending on prevailing atmospheric conditions, smoke from wildfires could potentially spread more radioactive material outside the exclusion zone.<ref>{{Cite web|url=https://www.bbc.com/news/magazine-18721292|title=Chernobyl's radioactive trees and the forest fire risk|last1=Evans|first1=Patrick|date=7 July 2012|website=BBC News|access-date=20 June 2018|archive-url=https://web.archive.org/web/20181017170142/https://www.bbc.com/news/magazine-18721292|archive-date=17 October 2018|url-status=live}}</ref><ref>{{cite web|url=http://www.smithsonianmag.com/science-nature/forests-around-chernobyl-arent-decaying-properly-180950075/|title=Forests Around Chernobyl Aren't Decaying Properly|last=Nuwer|first=Rachel|author-link=Rachel Nuwer |date=14 March 2014|website=[[Smithsonian (magazine)|Smithsonian]]|access-date=8 November 2018|archive-url=https://web.archive.org/web/20190102034531/https://www.smithsonianmag.com/science-nature/forests-around-chernobyl-arent-decaying-properly-180950075/|archive-date=2 January 2019|url-status=live}}</ref> In Belarus, the [[Bellesrad]] organization is tasked with overseeing [[Cultivation of the land|food cultivation]] and [[Forest management|forestry management]] in the area.
In April 2020, forest fires spread through {{convert|20000|ha}} of the exclusion zone, causing increased radiation from the release of caesium-137 and strontium-90 from the ground and biomass. The increase in radioactivity was detectable by the monitoring network but did not pose a threat to human health. The average radiation dose that Kyiv residents received as a result of the fires was estimated to be 1 nSv.<ref>{{Cite web|url=https://www.irsn.fr/EN/newsroom/News/Documents/IRSN_Information-Report_Fires-in-Ukraine-in-the-Exclusion-Zone-around-chernobyl-NPP_15042020.pdf|title=Fires in Ukraine in the exclusion zone around the Chernobyl power plant|website=IRNS|access-date=26 April 2020|archive-date=19 April 2020|archive-url=https://web.archive.org/web/20200419041110/https://www.irsn.fr/EN/newsroom/News/Documents/IRSN_Information-Report_Fires-in-Ukraine-in-the-Exclusion-Zone-around-chernobyl-NPP_15042020.pdf|url-status=live}}</ref><ref>{{Cite web|url=https://www.iaea.org/newscenter/pressreleases/iaea-sees-no-radiation-related-risk-from-fires-in-chornobyl-exclusion-zone|title=IAEA Sees No Radiation-Related Risk from Fires in Chornobyl Exclusion Zone|date=24 April 2020|website=www.iaea.org|language=en|access-date=26 April 2020|archive-date=1 May 2020|archive-url=https://web.archive.org/web/20200501033533/https://www.iaea.org/newscenter/pressreleases/iaea-sees-no-radiation-related-risk-from-fires-in-chornobyl-exclusion-zone|url-status=live}}</ref>
=== Recovery projects ===
The Chernobyl Trust Fund was created in 1991 by the United Nations to help victims of the Chernobyl accident.<ref>{{Cite news|url=https://www.nytimes.com/1995/11/29/world/chernobyl-trust-fund-depleted-as-problems-of-victims-grow.html|title=Chernobyl Trust Fund Depleted as Problems of Victims Grow|last=Crossette|first=Barbara|date=29 November 1995|work=The New York Times|access-date=28 April 2019|language=en-US|issn=0362-4331|archive-url=https://web.archive.org/web/20190428013532/https://www.nytimes.com/1995/11/29/world/chernobyl-trust-fund-depleted-as-problems-of-victims-grow.html|archive-date=28 April 2019|url-status=live}}</ref> It is administered by the [[United Nations Office for the Coordination of Humanitarian Affairs]], which also manages strategy formulation, resource mobilization, and advocacy efforts.<ref name=":1">{{Cite web|url=http://chernobyl.undp.org/english/history.shtml|title=History of the United Nations and Chernobyl|website=The United Nations and Chernobyl|archive-url=https://web.archive.org/web/20170719203953/http://chernobyl.undp.org/english/history.shtml|archive-date=19 July 2017|url-status=live|access-date=28 April 2019}}</ref> Beginning in 2002, under the [[United Nations Development Programme]], the fund shifted its focus from emergency assistance to long-term development.<ref name=":0" /><ref name=":1" />
The [[Chernobyl Shelter Fund]] was established in 1997 at the [[23rd G8 summit|G8 summit]] in Denver to finance the Shelter Implementation Plan (SIP). The plan called for transforming the site into an ecologically safe condition through stabilization of the sarcophagus and construction of the [[Chernobyl New Safe Confinement|New Safe Confinement]] structure. While the original cost estimate for the SIP was US$768 million, the 2006 estimate was $1.2 billion.
In 2003, the United Nations Development Programme launched the [[Chernobyl Recovery and Development Programme]] (CRDP) for the recovery of affected areas.<ref>{{cite web |url=http://www.undp.org.ua/?page=projects&projects=14 |title=CRDP: Chernobyl Recovery and Development Programme |website=United Nations Development Programme |access-date=31 July 2010 |archive-url=https://web.archive.org/web/20070704002250/http://www.undp.org.ua/?page=projects&projects=14 |url-status=dead |archive-date=4 July 2007}}</ref> The programme was initiated in February 2002 based on the recommendations in the report on Human Consequences of the Chernobyl Nuclear Accident. The main goal of the CRDP was supporting the [[Government of Ukraine]] in mitigating long-term social, economic, and ecological consequences of the Chernobyl catastrophe. CRDP works in the four most affected Ukrainian areas: [[Kyivska]], [[Zhytomyr Oblast|Zhytomyrska]], [[Chernihiv Oblast|Chernihivska]] and [[Rivnenska]].
More than 18,000 Ukrainian children affected by the disaster have been treated in the [[resort town]] of [[Tarará]], [[Cuba]], since 1990.<ref>{{cite news|last=Schipani|first=Andres|date=2 July 2009|title=Revolutionary care: Castro's doctors give hope to the children of Chernobyl|url=https://www.theguardian.com/world/2009/jul/02/cuba-chernobyl-health-children|work=[[The Guardian]]|access-date=15 June 2019|archive-date=26 June 2019|archive-url=https://web.archive.org/web/20190626180551/https://www.theguardian.com/world/2009/jul/02/cuba-chernobyl-health-children|url-status=live}}</ref>
The International Project on the Health Effects of the Chernobyl Accident was created and received US$20 million, mainly from Japan, in the hope of discovering the main cause of health problems due to [[iodine-131]] radiation. These funds were divided among Ukraine, Belarus, and Russia for investigation of health effects. As there was significant corruption in former Soviet countries, most foreign aid was given to Russia, and no results from the funding were demonstrated.
=== Tourism ===
First limited guided tours were begun in 2002.<ref>{{Cite web|url=https://www.theguardian.com/travel/2005/oct/23/ukraine.darktourism.observerescapesection|title=Strange and unsettling: my day trip to Chernobyl|first=Sarah|last=Johnstone|date=23 October 2005|via=The Guardian}}</ref> The 2007 release of the video game [[S.T.A.L.K.E.R.]] increased the site popularity<ref>https://www.washingtonpost.com/travel/2019/07/12/ukraine-wants-chernobyl-be-tourist-trap-scientists-warn-dont-kick-up-dust/</ref> and tour operators estimated that 40,000 tourists visited the site between 2007 and 2017.<ref>{{Cite web|url=https://thenational.shorthandstories.com/chernobyl-a-dark-tourist-attraction-v1/|title=Chernobyl: a disaster turned into a dark tourist attraction|first=LeAnne|last=Graves|website=chernobyl.thenational.ae}}</ref> Between 2017 and 2022, over 350,000 tourists visited the site, hitting the maximum peak of almost 125,000 visitors in 2019, coinciding with the release of HBO's mini-series about the disaster.<ref>{{Cite web|url=https://www.statista.com/statistics/1231428/number-of-tourists-in-chernobyl-exclusion-zone/|title=Number of Chernobyl Exclusion Zone visitors|website=Statista}}</ref><ref>{{Cite web|url=https://www.facebook.com/cotiz.org.ua/posts/236511471994731|title=Facebook|website=www.facebook.com}}</ref> After its release in July 2019, Ukrainian president [[Volodymyr Zelenskyy]] announced that the Chernobyl site would become an official tourist attraction. Zelenskyy said, "We must give this territory of Ukraine a new life."<ref>{{Cite web |last=Guy |first=Lianne Kolirin, Jack |title=Chernobyl to become official tourist attraction, Ukraine says |url=https://www.cnn.com/travel/article/chernobyl-tourist-attraction-intl-scli/index.html |access-date=29 April 2022 |website=CNN |date=11 July 2019 |language=en}}</ref><ref>{{Cite news|url=https://www.bbc.com/news/world-europe-48943814|title=Chernobyl to become 'official tourist attraction'|work=BBC News|date=10 July 2019|access-date=16 December 2019|archive-date=12 December 2019|archive-url=https://web.archive.org/web/20191212141728/https://www.bbc.com/news/world-europe-48943814|url-status=live}}</ref> Dr. T. Steen, a [[microbiology]] and [[immunology]] teacher at Georgetown's School of Medicine, recommends tourists to wear clothes and shoes they are comfortable with throwing away and to avoid plant life.<ref>{{Cite news |last=Mettler |first=Katie |date=12 July 2019 |title=Ukraine wants Chernobyl to be a tourist trap. But scientists warn: Don't kick up dust. |url=https://www.washingtonpost.com/travel/2019/07/12/ukraine-wants-chernobyl-be-tourist-trap-scientists-warn-dont-kick-up-dust/ |access-date=9 May 2022 |newspaper=The Washington Post}}</ref> Tourism has rebound after COVID in 2021, but the [[Russian invasion of Ukraine]] in early 2022 meant the Chernobyl area saw active fighting and the exclusion zone closed to all visitors. It remains closed to tourism as of summer 2024.<ref>{{Cite web|url=https://edition.cnn.com/travel/ukraine-kyiv-tourists-chernobyl-conflict/index.html|title=Chernobyl once brought tourists to Ukraine. They're still coming but now to see scars of different terror|first=Svitlana Vlasova, Radina|last=Gigova|date=26 June 2024|website=CNN}}</ref>
A parallel "stalker" subculture of illegal visitors to the zone developed, who roam the area for prolonged periods<ref>{{Cite web|url=https://slate.com/news-and-politics/2014/09/the-stalkers-inside-the-youth-subculture-that-explores-chernobyls-dead-zone.html|title=The Stalkers|first=Holly|last=Morris|date=26 September 2014|via=slate.com}}</ref> and some hiking into the zone over 100 times<ref>{{Cite web|url=https://www.new-east-archive.org/features/show/10946/into-the-zone-4-days-inside-chernobyls-secretive-stalker-subculture|title=Into the Zone: 4 days inside Chernobyl's secretive 'stalker' subculture — New East Digital Archive}}</ref> but often without taking appropriate precautions against radiation.<ref>{{Cite web|url=https://www.nationalgeographic.com/travel/article/exclusion-zone-chernobyl-ukraine|title=See Photos Taken on Illegal Visits to Chernobyl's Dead Zone|date=22 December 2017|website=Travel}}</ref>
==Long-term effects==
===Release and spread of radioactive materials===
{{Main|Effects of the Chernobyl disaster}}
Although it is difficult to compare the Chernobyl accident with a deliberate [[air burst]] nuclear detonation, it is estimated that Chernobyl released about 400 times more radioactive material than the combined [[atomic bombings of Hiroshima and Nagasaki]]. However, the Chernobyl disaster released only about one-hundredth to one-thousandth of the total radioactivity released during [[nuclear weapons testing]] at the height of the [[Cold War]], due to varying isotope abundances.<ref>{{cite web |url=http://www.iaea.org/Publications/Booklets/Chernoten/facts.html |title=Facts: The accident was by far the most devastating in the history of nuclear power |website=International Atomic Energy Agency|date=21 September 1997 |access-date=20 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110805035908/http://www.iaea.org/Publications/Booklets/Chernoten/facts.html |archive-date=5 August 2011 }}</ref>
Approximately {{convert|100000|km2|sqmi}} of land was significantly contaminated, with the worst-affected areas in Belarus, Ukraine, and [[Russian Soviet Federative Socialist Republic|Russia]].<ref name="MarplesDecade">{{cite journal |last=Marples |first=David R. |url=https://books.google.com/books?id=xAwAAAAAMBAJ&pg=PA20 |title=The Decade of Despair |journal=The Bulletin of the Atomic Scientists |date=May–June 1996 |volume=52 |pages=20–31 |issue=3 |doi=10.1080/00963402.1996.11456623 |bibcode=1996BuAtS..52c..20M |access-date=25 March 2016 |archive-url=https://web.archive.org/web/20170427033605/https://books.google.com/books?id=xAwAAAAAMBAJ&lpg=PA20&pg=PA20 |archive-date=27 April 2017 |url-status=live }}</ref> Lower contamination levels were detected across Europe, except for the [[Iberian Peninsula]].<ref name="torch"/><ref name="RFI 24">{{Cite news |language=fr |title=Tchernobyl, 20 ans après |website=[[Radio France Internationale|RFI]] |date=24 April 2006 |access-date=24 April 2006 |url=http://www.rfi.fr/actufr/articles/076/article_43250.asp |archive-url=https://web.archive.org/web/20060430063029/http://www.rfi.fr/actufr/articles/076/article_43250.asp |archive-date=30 April 2006 |url-status=live }}</ref>
On 28 April, workers at the Forsmark Nuclear Power Plant, {{convert|1100|km|mi|-1|abbr=on}} from Chernobyl, were found with radioactive particles on their clothing. Sweden's elevated radioactivity levels, detected at noon on 28 April, were traced back to the western Soviet Union.<ref>{{cite book |first=Richard Francis |last=Mould |title=Chernobyl Record: The Definitive History of the Chernobyl Catastrophe |isbn=978-0-7503-0670-6 |publisher=CRC Press |year=2000 |page=48}}</ref> Meanwhile, Finland also detected rising radiation levels, but a civil service strike delayed the response and publication.<ref>{{Cite book |url=http://www.stuk.fi/julkaisut/stuk-a/stuk-a217-s.1-198.pdf |title=Ympäristön Radioaktiivisuus Suomessa – 20 Vuotta Tshernobylista |publisher=Säteilyturvakeskus Stralsäkerhetscentralen (STUK, Radiation and Nuclear Safety Authority) |editor-last=Ikäheimonen |editor-first=T. K. |trans-title=Environmental Radioactivity in Finland – 20 Years from Chernobyl |archive-url=https://web.archive.org/web/20070808223651/http://www.stuk.fi/julkaisut/stuk-a/stuk-a217-s.1-198.pdf |archive-date=8 August 2007 |url-status=dead}}</ref>
{|class="wikitable sortable" style="margin:auto;"
|+Areas of Europe contaminated with [[Caesium-137|<sup>137</sup>Cs]]<ref>{{cite book |chapter-url=http://www-pub.iaea.org/MTCD/publications/PDF/Pub1239_web.pdf |chapter=3.1.5. Deposition of radionuclides on soil surfaces |pages=23–25 |year=2006 |title=Environmental Consequences of the Chernobyl Accident and their Remediation: Twenty Years of Experience, Report of the Chernobyl Forum Expert Group 'Environment' |publisher=International Atomic Energy Agency (IAEA) |location=Vienna |isbn=978-92-0-114705-9 |access-date=12 September 2013 |archive-date=9 April 2011 |archive-url=https://web.archive.org/web/20110409033554/http://www-pub.iaea.org/MTCD/publications/PDF/Pub1239_web.pdf |url-status=live }}</ref>
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Contamination from the Chernobyl accident was scattered irregularly depending on weather conditions, much of it deposited on mountainous regions such as the [[Alps]], the [[Wales|Welsh]] mountains and the [[Scottish Highlands]], where [[Adiabatic process|adiabatic cooling]] caused radioactive rainfall. The resulting patches of contamination were often highly localized, and localized water-flows contributed to large variations in radioactivity over small areas. Sweden and [[Norway]] also received heavy fallout when the contaminated air collided with a cold front, bringing rain.<ref name="GouldFire">{{cite book |last=Gould |first=Peter |title=Fire In the Rain: The Dramatic Consequences of Chernobyl |publisher=Johns Hopkins Press |year=1990 |location=Baltimore, Maryland}}</ref>{{rp|43–44, 78}} There was also [[Chernobyl groundwater contamination|groundwater contamination]].
Rain was deliberately [[Cloud seeding|seeded]] over {{convert|10000|km2|sqmi}} of Belarus by the [[Soviet Air Force]] to remove radioactive particles from clouds heading toward highly populated areas. Heavy, black-coloured rain fell on the city of [[Gomel]].<ref>{{cite news |last=Gray |first=Richard |date=22 April 2007 |title=How we made the Chernobyl rain |url=https://www.telegraph.co.uk/news/worldnews/1549366/How-we-made-the-Chernobyl-rain.html |url-status=live |archive-url=https://web.archive.org/web/20091118194620/http://www.telegraph.co.uk/news/worldnews/1549366/How-we-made-the-Chernobyl-rain.html |archive-date=18 November 2009 |access-date=27 November 2009 |newspaper=The Daily Telegraph |location=London, England}}</ref> Reports from Soviet and Western scientists indicate that the Belarusian SSR received about 60% of the contamination that fell on the former Soviet Union. However, the 2006 TORCH report stated that up to half of the volatile particles had actually landed outside the former USSR area currently making up Ukraine, Belarus, and Russia. An unconnected large area in [[Russian Soviet Federative Socialist Republic|Russian SFSR]] south of [[Bryansk]] was also contaminated, as were parts of northwestern [[Ukrainian Soviet Socialist Republic|Ukrainian SSR]]. Studies in surrounding countries indicate that more than one million people could have been affected by radiation.<ref name="WNA-Chernobyl">{{cite web |url=http://world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/Chernobyl-Accident/ |title=Chernobyl Accident 1986 |date=April 2015 |website=[[World Nuclear Association]] |access-date=21 April 2015 |archive-url=https://web.archive.org/web/20150420143903/http://www.world-nuclear.org/info/safety-and-security/safety-of-plants/chernobyl-accident/ |archive-date=20 April 2015 |url-status=live }}</ref> 2016 data from a long-term monitoring program<ref>{{cite web |url=http://wwwzb1.fz-juelich.de/verlagextern1/redirect.asp?id_schriften=48598&URL_DMS=http://dmssrv.zb.kfa-juelich.de/w2p2/autologin1.asp?action=ExpDownload&Path=%5CPublic%20FZJ%5CPublikationen%5CSchriftenreihen%5CEnergie_Umwelt_342.pdf&online=online& |last1=Zoriy |first1=Pedro |last2=Dederichs |first2=Herbert |last3=Pillath |first3=Jürgen |last4=Heuel-Fabianek |first4=Burkhard |last5=Hill |first5=Peter |last6=Lennartz |first6=Reinhard |title=Long-term monitoring of radiation exposure of the population in radioactively contaminated areas of Belarus – The Korma Report II (1998–2015) |volume=342 |work=Schriften des Forschungszentrums Jülich: Reihe Energie & Umwelt / Energy & Environment |publisher=Forschungszentrum Jülich, Zentralbibliothek, Verlag |year=2016 |access-date=21 December 2016 }}{{Dead link|date=March 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> showed a decrease in internal [[Ionizing radiation|radiation exposure]] of the inhabitants of a region in Belarus close to Gomel.
In Western Europe, precautionary measures taken in response to the radiation included banning the importation of certain foods. A 2006 study found contamination was "relatively limited, diminishing from west to east", such that a hunter consuming 40 kilograms of contaminated wild boar in 1997 would be exposed to about one millisievert.<ref>{{cite journal |date=March–April 2006 |title=Nouveau regard sur Tchernobyl: L'impact sur la santé et l'environnement |trans-title=A new look at Chernobyl: The impact on health and the environment |url=http://www.sfen.org/fr/themes/tchernobyl.pdf |url-status=dead |journal=Extrait de la Revue Générale Nucléaire |language=fr |publisher=Société française d'énergie nucléaire |page=7 |archive-url=https://web.archive.org/web/20101228021056/http://www.sfen.org/fr/themes/tchernobyl.pdf |archive-date=28 December 2010 |trans-journal=Excerpt of the General Nuclear Review}}</ref>
==== Relative isotopic abundances ====
{{Main|Behavior of nuclear fuel during a reactor accident#Chernobyl release}}
The Chernobyl release was characterized by the physical and chemical properties of the radio-isotopes in the core. Particularly dangerous were the highly radioactive [[fission products]], those with high [[nuclear decay]] rates that accumulate in the food chain, such as some of the isotopes of [[iodine]], [[caesium]] and [[strontium]]. Iodine-131 was and caesium-137 remains the two most responsible for the radiation exposure received by the general population.<ref name="OECD02-Ch2"/>
[[File:AirDoseChernobylVector.svg|thumb|upright=1.6|Contributions of the various isotopes to the atmospheric [[absorbed dose]] in the contaminated area of Pripyat, from soon after the accident to 27 years after the accident]]
[[Image:Totalexternaldoseratecher.png|thumb|upright=1.6|[[Logarithmic scale]]d graph of the [[Equivalent dose|external relative gamma dose]] for a person in the open near the disaster site. The dose that was calculated is the [[equivalent dose|relative]] external gamma dose rate for a person standing in the open. The exact dose to a person in the real world requires a personnel-specific [[radiation dose reconstruction]] analysis and whole body count exams.<ref name="nih.gov">{{Cite journal |pmc = 149393|year = 2002|last1 = Zamostian|first1 = P.|title = Influence of various factors on individual radiation exposure from the chernobyl disaster|journal = Environmental Health|volume = 1|issue = 1|pages = 4|last2 = Moysich|first2 = K. B.|last3 = Mahoney|first3 = M. C.|last4 = McCarthy|first4 = P.|last5 = Bondar|first5 = A.|last6 = Noschenko|first6 = A. G.|last7 = Michalek|first7 = A. M.|pmid = 12495449|doi = 10.1186/1476-069X-1-4 | bibcode=2002EnvHe...1....4Z | doi-access=free }}</ref>]]
At different times after the accident, different [[isotope]]s were responsible for the majority of the external dose. The remaining quantity of any radioisotope, and therefore the activity of that isotope, after 7 decay [[half-life|half-lives]] have passed, is less than 1% of its initial magnitude,<ref>{{cite web |url=http://www.srp-uk.org/resources/rules-of-thumb-a-practical-hints |title=Rules of Thumb & Practical Hints |website=Society for Radiological Protection |access-date=12 September 2013 |url-status=dead |archive-url=https://web.archive.org/web/20110628183818/http://www.srp-uk.org/resources/rules-of-thumb-a-practical-hints |archive-date=28 June 2011}}</ref> and it continues to reduce beyond 0.78% after 7 half-lives to 0.10% remaining after 10 half-lives have passed and so on.<ref>{{cite web |url=http://www.colorado.edu/physics/2000/isotopes/radioactive_decay3.html |title=Halflife |website=[[University of Colorado Boulder]] |date=20 September 1999 |access-date=12 September 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130830080624/http://www.colorado.edu/physics/2000/isotopes/radioactive_decay3.html |archive-date=30 August 2013 }}</ref><ref>{{cite web |first=Ken |last=Lyle |url=http://www.chem.purdue.edu/gchelp/howtosolveit/Nuclear/Half_Life.htm |title=Mathematical half life decay rate equations |website=[[Purdue University]] |access-date=12 September 2013 |archive-url=https://web.archive.org/web/20131004213526/http://www.chem.purdue.edu/gchelp/howtosolveit/Nuclear/Half_Life.htm |archive-date=4 October 2013 |url-status=live }}</ref> Some radionuclides have decay products that are likewise radioactive, which is not accounted for here. The release of radioisotopes from the nuclear fuel was largely controlled by their [[boiling point]]s, and the majority of the [[radioactivity]] present in the core was retained in the reactor.
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* 20 to 40% of all core [[caesium-137]] was released, 85 PBq in all.<ref name="OECD02-Ch2"/><ref>{{cite web |url=http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-24GMT11:24 |title=Unfall im japanischen Kernkraftwerk Fukushima |website=[[Central Institution for Meteorology and Geodynamics]] |language=de |date=24 March 2011 |access-date=20 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110819093109/http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-24GMT11:24 |archive-date=19 August 2011 }}</ref> Caesium was released in [[particulate|aerosol]] form; caesium-137, along with [[isotopes of strontium]], are the two primary elements preventing the Chernobyl exclusion zone being re-inhabited.<ref name="stanford1">{{cite web |url=http://large.stanford.edu/courses/2012/ph241/wessells1/ |title=Cesium-137: A Deadly Hazard |last=Wessells |first=Colin |date=20 March 2012 |website=[[Stanford University]] |access-date=13 February 2013 |archive-url=https://web.archive.org/web/20131030013102/http://large.stanford.edu/courses/2012/ph241/wessells1/ |archive-date=30 October 2013 |url-status=live }}</ref> {{val|8.5|e=16|u=Bq}} equals 24 kilograms of caesium-137.<ref name="stanford1"/> Cs-137 has a half-life of 30 years.<ref name="OECD02-Ch2"/>
* [[Tellurium-132]], half-life 78 hours, an estimated 1150 PBq was released.<ref name="OECD02-Ch2"/>
* An early estimate for total [[nuclear fuel]] material released to the environment was {{val|3|1.5}}%; this was later revised to {{val|3.5|0.5}}%. This corresponds to the atmospheric emission of {{convert|6|t|LT ST}} of fragmented fuel.<ref name="OECD1995">{{cite web |url=https://www.oecd-nea.org/rp/chernobyl/chernobyl-1995.pdf |title=Chernobyl, Ten Years On: Assessment of Radiological and Health Impact |year=1995 |website=OECD-NEA |access-date=3 June 2015 |archive-url=https://web.archive.org/web/20150622010906/https://www.oecd-nea.org/rp/chernobyl/chernobyl-1995.pdf |archive-date=22 June 2015 |url-status=live }}</ref>
===Environmental impact===
{{Main article|Effects of the Chernobyl disaster#Long-term effects on plant and animal health}}
==== Water bodies ====
[[File:Chernobyl, Ukraine.jpg|thumb|upright=1.5|Reactor and surrounding area in April 2009]]
The Chernobyl nuclear power plant is located next to the Pripyat River, which feeds into the Dnieper reservoir system, one of the largest surface water systems in Europe, which at the time supplied water to Kiev's 2.4 million residents, and was still in spring flood when the accident occurred.<ref name="MarplesSocialImpact"/>{{rp|60}} The radioactive contamination of aquatic systems therefore became a major problem in the immediate aftermath
In the most affected areas of Ukraine, levels of radioactivity
[[Groundwater]] was not badly affected by the Chernobyl accident since [[radionuclide]]s with short half-lives decayed away long before they could affect groundwater supplies, and longer-lived radionuclides such as radiocaesium and radiostrontium were [[adsorption|adsorbed]] to surface [[soil]]s before they could transfer to groundwater.<ref name="IAEA"/> However, significant transfers of radionuclides to groundwater have occurred from [[waste disposal]] sites in the {{convert|30|km|mi|0|abbr=on}} exclusion zone around Chernobyl. Although there is a potential for transfer of radionuclides from these disposal sites off-site
[[File:Chernobyl radiation map 1996.svg|thumb|upright=2|Radiation levels around Chernobyl in 1996]]
[[Bio-accumulation]] of radioactivity in fish<ref name=kryshev95>{{cite journal |doi=10.1016/0265-931X(94)00042-U |title=Radioactive contamination of aquatic ecosystems following the Chernobyl accident |year=1995 |last1=Kryshev |first1=I. I. |journal=Journal of Environmental Radioactivity |volume=27 |issue=3 |pages=207–219|bibcode=1995JEnvR..27..207K }}</ref> resulted in concentrations significantly above guideline maximum levels for consumption.<ref name=smithber05/> Guideline maximum levels for radiocaesium in fish vary but are approximately 1000 Bq/kg in the [[European Union]].<ref name="euregs">EURATOM Council Regulations No. 3958/87, No. 994/89, No. 2218/89, No. 770/90.</ref> In the [[Kiev Reservoir]] in Ukraine, concentrations in fish were in the range of 3000 Bq/kg during the early years after the accident.<ref name=kryshev95/> In small [[closed lake|"closed" lakes]] in Belarus and the Bryansk region of Russia, concentrations in a number of fish species varied from 100 to 60,000 Bq/kg during 1990–1992.<ref name=fleishman94>{{cite journal |doi=10.1016/0265-931X(94)90050-7 |title=137Cs in fish of some lakes and rivers of the Bryansk region and north-west Russia in 1990–1992 |year=1994 |last1=Fleishman |first1=David G. |last2=Nikiforov |first2=Vladimir A. |last3=Saulus |first3=Agnes A. |last4=Komov |first4=Victor T. |journal=Journal of Environmental Radioactivity |volume=24 |issue=2 |pages=145–158}}</ref> The contamination of fish caused short-term concern in parts of the UK and Germany and in the long term in the affected areas of Ukraine, Belarus, and Russia as well as Scandinavia.<ref name=smithber05/>
==== Flora, fauna, and funga ====
<!--This section is linked from https://en.wikipedia.org/wiki/Radiotrophic_fungus. Please adjust the section title and link accordingly-->[[File:Kiev-UkrainianNationalChernobylMuseum 15.jpg|thumb|upright=1.4|Piglet with [[dipygus]] on exhibit at the [[Ukrainian National Chernobyl Museum]]]]After the disaster, {{convert|4|km2|sqmi|spell=in}} of [[pine]] forest directly downwind of the reactor turned reddish-brown and died, earning the name "[[Red Forest]]".<ref name="bbcmulvey" /> Some animals in the worst-hit areas also died or stopped reproducing. Most [[domestic animal]]s were removed from the exclusion zone, but horses left on an island in the Pripyat River {{convert|6|km|mi|0|abbr=on}} from the power plant died when their [[thyroid]] glands were destroyed by radiation doses of 150–200 Sv.<ref name="iaea1991">{{cite book |title=The International Chernobyl Project: Technical Report |date=1991 |publisher=IAEA |isbn=978-9-20129-191-2 |location=Vienna, Austria}}</ref> Some cattle on the same island died and those that survived were stunted. The next generation appeared to be normal.<ref name="iaea1991" /> The mutation rates for plants and animals have increased by a factor of 20 because of the release of radionuclides from Chernobyl. There is evidence for elevated mortality rates and increased rates of reproductive failure in contaminated areas, consistent with the expected frequency of deaths due to mutations.<ref>{{Cite journal |last1=Møller |first1=A. P. |last2=Mousseau |first2=T. A. |date=1 December 2011 |title=Conservation consequences of Chernobyl and other nuclear accidents |url=https://www.sciencedirect.com/science/article/pii/S000632071100317X |journal=Biological Conservation |language=en |volume=144 |issue=12 |pages=2787–2798 |doi=10.1016/j.biocon.2011.08.009 |bibcode=2011BCons.144.2787M |s2cid=4110805 |issn=0006-3207}}</ref>
On farms in [[Narodychi Raion]] of Ukraine it is claimed that from 1986 to 1990 nearly 350 animals were born with gross deformities; in comparison, only three abnormal births had been registered in the five years prior.<ref>{{cite journal|last1=Weigelt|first1=E.|last2=Scherb|first2=H.|year=2004|title=Spaltgeburtenrate in Bayern vor und nach dem Reaktorunfall in Tschernobyl|journal=Mund-, Kiefer- und Gesichtschirurgie|volume=8|issue=2|pages=106–110|doi=10.1007/s10006-004-0524-1|pmid=15045533|s2cid=26313953}}</ref>{{better source needed|date=June 2019}}
Subsequent research on microorganisms, while limited, suggests that in the aftermath of the disaster, bacterial and viral specimens exposed to the radiation underwent rapid changes.<ref name = "Yablokov2009">{{Cite journal|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1749-6632.2009.04830.x|title=Chapter III. Consequences of the Chernobyl Catastrophe for the Environment|first1=Alexey V.|last1=Yablokov|first2=Vassily B.|last2=Nesterenko|first3=Alexey V.|last3=Nesterenko|date=21 September 2009|journal=Annals of the New York Academy of Sciences|volume=1181|issue=1|pages=221–286|via=Wiley Online Library|doi=10.1111/j.1749-6632.2009.04830.x|pmid=20002049|bibcode=2009NYASA1181..221Y|s2cid=2831227}}</ref> Activations of soil micromycetes have been reported.<ref name = Yablokov2009 /> A paper in 1998 reported the discovery of an [[Escherichia coli]] mutant that was hyper-resistant to a variety of DNA-damaging elements, including x-ray radiation, [[UV-C]], and [[4-nitroquinoline 1-oxide]] (4NQO).<ref>Zavilgelsky GB, Abilev SK, Sukhodolets SS, Ahmad SI. Isolation and analysis of UV and radio-resistant bacteria from Chernobyl. ''J Photochem Photobiol B'', May 1998: vol. 43, no. 2, pp. 152–157.</ref> [[Cladosporium sphaerospermum]], a species of fungus that has thrived in the Chernobyl contaminated area, has been investigated for the purpose of using the fungus' particular melanin to protect against high-radiation environments, such as space travel.<ref>{{Cite web |url=https://learningenglish.voanews.com/a/scientists-study-chernobyl-fungus-as-protection-against-space-radiation/5524225.html |title=Voice of America. "Scientists Study Chernobyl Fungus as Protection against Space Radiation." Online resource, last updated August 2020. Retrieved June 2021. |date=2 August 2020 |access-date=12 June 2021 |archive-date=5 March 2022 |archive-url=https://web.archive.org/web/20220305100444/https://learningenglish.voanews.com/a/scientists-study-chernobyl-fungus-as-protection-against-space-radiation/5524225.html |url-status=live }}</ref> The disaster has been described by lawyers, academics and journalists as an example of [[ecocide]].<ref>{{Cite web |last=Rybacki |first=Josef |date=February 2021 |title=Establishing the crime of 'ecocide' |url=https://www.lawgazette.co.uk/practice-points/establishing-the-crime-of-ecocide/5107209.article |access-date=21 June 2023 |website=Law Gazette |language=en}}</ref><ref>{{Cite web |last=Krogh |first=Peter F. (Peter Frederic) |date=1994 |title=Ecocide : a Soviet legacy |url=https://repository.library.georgetown.edu/handle/10822/552539 |access-date=21 June 2023 |website=Great Decisions 1994 |language=English}}</ref><ref>{{Cite web |title=Ecocide – the genocide of the 21st century? Eastern European perspective |url=http://www.cirsd.org/en/expert-analysis?slug=ecocide-%E2%80%93-the-genocide-of-the-21st-century-eastern-european-perspective |access-date=21 June 2023 |website=CIRSD}}</ref><ref>{{Cite book |last1=Feshbach |first1=Murray |title=Ecocide in the USSR: health and nature under siege |last2=Friendly |first2=Alfred |date=1992 |publisher=Basic Books |isbn=978-0-465-01664-8 |location=New York}}</ref>
====Human food chain====
With [[Environmental radioactivity#Soil|radiocaesium binding less with humic acid, peaty soils]] than the known binding "fixation" that occurs on [[kaolinite]]-rich clay soils, many marshy areas of Ukraine had the highest soil to dairy-milk transfer coefficients, of soil activity in ~ 200 kBq/m<sup>2</sup> to dairy milk activity in Bq/L, that had ever been reported, with the transfer, from initial land activity into milk activity, ranging from 0.3<sup>−2</sup> to 20<sup>−2</sup> times that which was on the soil.<ref name="nih.gov"/>
In 1987, Soviet medical teams conducted some 16,000 [[Whole-body counting|whole-body count]] examinations on inhabitants in otherwise comparatively lightly contaminated regions with good prospects for recovery. This was to determine the effect of banning local food and using only food imports on the internal body burden of radionuclides in inhabitants. Concurrent agricultural [[countermeasure]]s were used when cultivation did occur, to further reduce the soil to human transfer as much as possible. The expected highest body activity was in the first few years, where the unabated ingestion of local food resulted in the transfer of activity from soil to body. After the [[dissolution of the Soviet Union]], the now reduced scale initiative to monitor human body activity in these regions of Ukraine, recorded a small and gradual half-decade-long rise in internal committed dose before returning to the previous trend of observing lower body counts each year.
This momentary rise is hypothesized to be due to the cessation of the Soviet food imports together with many villagers returning to older dairy food cultivation practices and large increases in wild berry and mushroom foraging.<ref name="nih.gov"/>
[[File:Red Forest Hill.jpg|thumb|After the disaster, {{convert|4|km2|sqmi|spell=in}} of pine forest directly downwind of the reactor turned reddish-brown and died, earning the name of the "[[Red Forest]]", though it soon recovered.<ref name=bbcmulvey>{{cite web |url=http://news.bbc.co.uk/2/hi/europe/4923342.stm |title=Wildlife defies Chernobyl radiation |last=Mulvey |first=Stephen |date=20 April 2006 |website=BBC News |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20171105054818/http://news.bbc.co.uk/2/hi/europe/4923342.stm |archive-date=5 November 2017 |url-status=live }}</ref> This photograph was taken years later, in March 2009,<ref>{{cite web |url=http://timmsuess.com/projects/chernobyl-journal/ |title=Chernobyl journal |last=Suess |first=Timm |date=March 2009 |website=timmsuess.com |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20180917034354/http://timmsuess.com/projects/chernobyl-journal/ |archive-date=17 September 2018 |url-status=dead }}</ref> after the forest began to grow again, with the lack of foliage at the time of the photograph merely due to the local [[winter]] at the time.<ref name=environment>{{cite journal |url=http://www.nsrl.ttu.edu/chornobyl/wildlifepreserve.htm |title=The Chernobyl nuclear disaster and subsequent creation of a wildlife preserve |last1=Baker |first1=Robert J. |first2=Ronald K. |last2=Chesser |date=2000 |journal=Environmental Toxicology and Chemistry |volume=19 |number=5 |pages=1231–1232 |access-date=8 November 2018 |via=Natural Science Research Laboratory |doi=10.1002/etc.5620190501 |s2cid=17795690 |archive-url=https://web.archive.org/web/20180930055813/http://www.nsrl.ttu.edu/chornobyl/wildlifepreserve.htm |archive-date=30 September 2018 |url-status=live |doi-access=free }}</ref>]]
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In a 2007 paper, a robot sent into the No. 4 reactor returned with samples of black, [[melanin]]-rich [[radiotrophic fungus|radiotrophic fungi]] that grow on the reactor's walls.<ref>{{cite web |url=https://www.sciencedaily.com/releases/2007/05/070522210932.htm |title='Radiation-Eating' Fungi Finding Could Trigger Recalculation Of Earth's Energy Balance And Help Feed Astronauts |date=23 May 2007 |website=Science Daily |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181108224505/https://www.sciencedaily.com/releases/2007/05/070522210932.htm |archive-date=8 November 2018}}</ref>
Of the 440,350 wild boar killed in the 2010 hunting season in Germany, approximately one thousand were contaminated with levels of radiation above the permitted limit of 600 becquerels of caesium per kilogram, of dry weight, due to residual radioactivity from Chernobyl.<ref>{{cite news |url=https://www.welt.de/wissenschaft/article12874184/Deutsche-Wildschweine-immer-noch-verstrahlt.html |title=25 Jahre Tschernobyl: Deutsche Wildschweine immer noch verstrahlt |trans-title=25 years of Chernobyl: German wild boars still contaminated |newspaper=[[Die Welt]] |language=de |date=18 March 2011 |access-date=20 August 2011 |archive-url=https://web.archive.org/web/20110831151558/http://www.welt.de/wissenschaft/article12874184/Deutsche-Wildschweine-immer-noch-verstrahlt.html |archive-date=31 August 2011 |url-status=live }}</ref>
In 2015, long-term empirical data showed no evidence of a negative influence of radiation on mammal abundance.<ref>{{cite journal |last1=Deryabina |first1=T. G. |last2=Kuchmel |first2=S. V. |last3=Nagorskaya |first3=L. L. |last4=Hinton |first4=T. G. |last5=Beasley |first5=J. C. |last6=Lerebours |first6=A. |last7=Smith |first7=J. T. |date=October 2015 |title=Long-term census data reveal abundant wildlife populations at Chernobyl |journal=Current Biology |volume=25 |issue=19 |pages=R824–R826 |bibcode=2015CBio...25.R824D |doi=10.1016/j.cub.2015.08.017 |pmid=26439334 |doi-access=free}}</ref>
====Precipitation on distant high ground====
On high ground, such as mountain ranges, there is increased precipitation due to [[adiabatic cooling]]. This resulted in localized concentrations of contaminants on distant areas; higher in Bq/m<sup>2</sup> values to many lowland areas much closer to the source of the plume
The Norwegian Agricultural Authority reported that in 2009, a total of 18,000 livestock in Norway required uncontaminated feed for a period before slaughter, to ensure that their meat had an activity below the government permitted value of [[caesium]] per kilogram deemed suitable for human consumption. This contamination was due to residual radioactivity from Chernobyl in the mountain plants they graze on in the wild during the summer. 1,914 sheep required uncontaminated feed for a time before slaughter during 2012, with these sheep located in only 18 of Norway's municipalities, a decrease from the 35 municipalities in 2011 and the 117 municipalities affected during 1986.<ref name="thelocal1">{{cite news |url=http://www.thelocal.no/20130923/chernobyl-radiation-in-norway-sheep-hits-new-low |title=Record low number of radioactive sheep |first=Richard |last=Orange |date=23 September 2013 |newspaper=[[The Local]] |location=Norway |access-date=1 November 2013 |archive-url=https://web.archive.org/web/20131103130842/http://www.thelocal.no/20130923/chernobyl-radiation-in-norway-sheep-hits-new-low |archive-date=3 November 2013 |url-status=live }}</ref> The after-effects of Chernobyl on the mountain lamb industry in Norway were expected to be seen for a further 100 years, although the severity of the effects would decline over that period.<ref>{{cite web |url=https://www.slf.dep.no/no/erstatning/palegg-og-restriksjoner/radioaktivitet/fortsatt-nedforing-etter-radioaktivitet-i-dyr-som-har-v%C3%A6rt-p%C3%A5-utmarksbeite |title=Fortsatt nedforing etter radioaktivitet i dyr som har vært på utmarksbeite |website=Statens landbruksforvaltning |language=no |date=30 June 2010 |access-date=21 June 2015 |url-status=dead |archive-url=https://web.archive.org/web/20131103080938/https://www.slf.dep.no/no/erstatning/palegg-og-restriksjoner/radioaktivitet/fortsatt-nedforing-etter-radioaktivitet-i-dyr-som-har-v%C3%A6rt-p%C3%A5-utmarksbeite |archive-date=3 November 2013}}</ref>
The United Kingdom restricted the movement of sheep from upland areas when radioactive [[caesium-137]] fell across parts of Northern Ireland, Wales, Scotland, and northern England. In the immediate aftermath of the disaster, the movement of a total of 4,225,000 sheep was restricted across a total of 9,700 farms, to prevent contaminated meat entering the human food chain.<ref name="Guardian-2009">{{cite news |first1=Terry |last1=Macalister |first2=Helen |last2=Carter |title=Britain's farmers still restricted by Chernobyl nuclear fallout |date=12 May 2009 |url=https://www.theguardian.com/environment/2009/may/12/farmers-restricted-chernobyl-disaster |newspaper=[[The Guardian]] |access-date=1 November 2013 |archive-url=https://web.archive.org/web/20131102095940/http://www.theguardian.com/environment/2009/may/12/farmers-restricted-chernobyl-disaster |archive-date=2 November 2013 |url-status=live }}</ref> The number of sheep and farms affected has decreased since 1986. Northern Ireland was released from all restrictions in 2000, and by 2009, 369 farms containing around 190,000 sheep remained under the restrictions in Wales, Cumbria, and northern Scotland.<ref name="Guardian-2009" /> The restrictions applying in Scotland were lifted in 2010, while those applying to Wales and Cumbria were lifted during 2012, meaning no farms in the UK remain restricted because of Chernobyl.<ref name="Indy-Scot-2012">{{cite news |first1=Kevin |last1=Rawlinson |first2=Rachel |last2=Hovenden |title=Scottish sheep farms finally free of Chernobyl fallout |date=7 July 2010 |url=https://www.independent.co.uk/news/science/scottish-sheep-farms-finally-free-of-chernobyl-fallout-2020059.html |newspaper=[[The Independent]] |access-date=1 November 2013 |archive-url=https://web.archive.org/web/20131216193052/http://www.independent.co.uk/news/science/scottish-sheep-farms-finally-free-of-chernobyl-fallout-2020059.html |archive-date=16 December 2013 |url-status=live }}</ref><ref name="BBC-June-2012">{{cite news |title=Post-Chernobyl disaster sheep controls lifted on last UK farms |date=1 June 2012 |website=BBC News |url=https://www.bbc.co.uk/news/uk-england-cumbria-18299228 |access-date=1 November 2013 |archive-url=https://web.archive.org/web/20131220173331/http://www.bbc.co.uk/news/uk-england-cumbria-18299228 |archive-date=20 December 2013 |url-status=live }}</ref> The legislation used to control sheep movement and compensate farmers was revoked during 2012, by the relevant authorities in the UK.<ref name="UKFSA-01">{{cite web |url=http://www.food.gov.uk/news-updates/news/2012/nov/chernobyl |title=Welsh sheep controls revoked |access-date=1 November 2013 |website=[[Food Standards Agency]] |date=29 November 2012 |archive-url=https://web.archive.org/web/20131103142059/http://www.food.gov.uk/news-updates/news/2012/nov/chernobyl |archive-date=3 November 2013 |url-status=live }}</ref>
=== Human impact ===
{{Main|Effects of the Chernobyl disaster#Long-term health effects}}
[[File:View of Chernobyl taken from Pripyat.JPG|thumb|upright=1.6|[[Pripyat]] lies abandoned with the Chernobyl facility visible in the distance]]
[[File:G radiation-level scale 01.png|thumb|right|upright=1.8| Radiation exposure to first responders at Chernobyl in comparison to a range of situations, from normal activities up to nuclear accident. Each step up the scale indicates a tenfold increase in radiation level.]]
====Acute radiation effects and immediate aftermath====
The only known causal deaths from the accident involved plant workers and firefighters. The reactor explosion killed two engineers, and 28 others died within three months from [[acute radiation syndrome]] (ARS)
Most serious ARS cases were treated with the assistance of American specialist [[Robert Peter Gale]], who supervised bone marrow transplant procedures, although these were unsuccessful.<ref>{{Cite journal |doi = 10.1007/s10512-012-9607-5|title = Medical consequences of the Chernobyl accident: Aftermath and unsolved problems|journal = Atomic Energy|volume = 113|issue = 2|pages = 135–142|year = 2012|last1 = Guskova|first1 = A. K.|s2cid = 95291429}}</ref><ref>{{cite news |url=https://www.nytimes.com/1986/07/13/magazine/the-chernobyl-doctor.html |title=The Chernobyl Doctor |date=13 July 1986 |first=Eric |last=Lax |page=22 |newspaper=[[The New York Times]] |access-date=22 July 2019 |archive-date=2 July 2019 |archive-url=https://web.archive.org/web/20190702171033/https://www.nytimes.com/1986/07/13/magazine/the-chernobyl-doctor.html
==== Long-term impact ====
In the 10 years following the accident, 14 more people who had been initially hospitalized died, mostly from causes unrelated to radiation exposure, with only two deaths resulting from [[myelodysplastic syndrome]].<ref name=":5" /> Scientific consensus, supported by the [[Chernobyl Forum]], suggests no statistically significant increase in solid cancer incidence among rescue workers.<ref name=":6">International Atomic Energy Agency, Chernobyl's Legacy: Health, Environmental and Socio-Economic Impacts and Recommendations to the Governments of Belarus, the Russian Federation, and Ukraine, The Chernobyl Forum: 2003–2005.</ref> However, childhood thyroid cancer increased, with about 4,000 new cases reported by 2002 in contaminated areas of Belarus, Russia, and Ukraine, largely due to high levels of [[radioactive iodine]]. The recovery rate is ~99%, with 15 terminal cases reported.<ref name=":6" /> No increase in mutation rates was found among children of liquidators or those living in contaminated areas.<ref name="pmid15725606" />
Psychosomatic illness and post-traumatic stress, driven by widespread fear of radiological disease, have had a significant impact, often exacerbating health issues by fostering fatalistic attitudes and harmful behaviors
By 2000, the number of Ukrainians claiming radiation-related "sufferer" status reached 3.5 million, or 5% of the population, many of whom were resettled from contaminated zones or former Chernobyl workers.<ref name="PetrynaLE" />{{rp|4–5}} Increased medical surveillance after the accident led to higher recorded rates of benign conditions and cancers.<ref name="MarplesDecade" />
====Effects of main harmful radionuclides====
The four most harmful radionuclides spread from Chernobyl were [[iodine-131]], [[caesium-134]], [[caesium-137]] and [[strontium-90]], with half-lives of 8 days, 2.07 years, 30.2 years and 28.8 years respectively.<ref name="TORCH">{{cite book |last1=Fairlie |first1=Ian |title=The Other Report on Chernobyl (TORCH) |last2=Sumner |first2=David |publisher=The European Greens |year=2006 |location=Berlin, Germany}}</ref>{{rp|8}} The iodine was initially viewed with less alarm than the other isotopes, because of its short half-life, but it is highly volatile and appears to have travelled furthest and caused the most severe health problems.<ref name="MarplesDecade"/>{{rp|24}} Strontium is the least volatile and of main concern in the areas near Chernobyl.<ref name="TORCH"/>{{rp|8}}
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Long term hazards such as caesium tends to accumulate in vital organs such as the heart,<ref name="KuchinskayaWeWill">{{cite thesis |last1=Kuchinskaya |first1=Olga |title='We will die and become science': the production of invisibility and public knowledge about Chernobyl radiation effects in Belarus |date=2007 |publisher=University of California San Diego |url=https://escholarship.org/uc/item/9fb6527b |type=PhD Thesis |page=133 |access-date=14 July 2015 |archive-date=15 July 2015 |archive-url=https://web.archive.org/web/20150715075426/https://escholarship.org/uc/item/9fb6527b |url-status=live}}</ref> while strontium accumulates in bones and may be a risk to bone-marrow and [[lymphocyte]]s.<ref name="TORCH"/>{{rp|8}} Radiation is most damaging to cells that are actively dividing. In adult mammals cell division is slow, except in hair follicles, skin, bone marrow and the gastrointestinal tract, which is why vomiting and hair loss are common symptoms of acute radiation sickness.<ref name="MycioWormwood">{{cite book |title=Wormwood Forest: A Natural History of Chernobyl |url=https://archive.org/details/wormwoodforest00mary |url-access=registration |last=Mycio |first=Mary |year=2005 |location=Washington, D.C. |publisher=Joseph Henry Press |isbn=978-0-30910-309-1}}</ref>{{rp|42}}
====Disputed investigation====
The mutation rates among animals in the Chernobyl zone have been a topic of ongoing scientific debate
====Withdrawn investigation====
In 1996, geneticist Ronald Chesser and Robert Baker published a paper<ref>{{cite journal |last1=Barker |first1=Robert J. |last2=Van Den Bussche |first2=Ronald A. |last3=Wright |first3=Amanda J. |last4=Wiggins |first4=Lara E. |last5=Hamilton |first5=Meredith J. |last6=Reat |first6=Erin P. |last7=Smith |first7=Micheal H. |last8=Lomakin |first8=Micheal D. |last9=Chesser |first9=Ronald K. |title=High levels of genetic change in rodents of Chernobyl |journal=Nature |date=April 1996 |volume=380 |issue=6576 |pages=707–708 |doi=10.1038/380707a0|pmid=8614463 |bibcode=1996Natur.380..707B |s2cid=4351740 }} {{Retracted|doi=10.1038/36382|pmid=9363899|intentional=yes}}</ref> on the thriving [[vole]] population within the exclusion zone, in which the central conclusion
==== Abortions ====
Following the accident, journalists encouraged public mistrust of medical professionals.<ref name="kasperson160">{{cite book |last1=Kasperson |first1=Roger E. |title=Communicating Risks to the Public: International Perspectives |last2=Stallen |first2=Pieter Jan M. |publisher=Springer Science and Media |year=1991 |isbn=978-0-7923-0601-6 |location=Berlin, Germany |pages=160–162}}</ref> This media-driven framing led to an increase in induced abortions across Europe out of fears of radiation. An estimated 150,000 elective abortions were performed worldwide due to [[radiophobia]].<ref name="kasperson160"/><ref name="Knudsen"/><ref name="Trichopoulos">{{cite journal |last1=Trichopoulos |first1=D. |last2=Zavitsanos |first2=X. |last3=Koutis |first3=C. |last4=Drogari |first4=P. |last5=Proukakis |first5=C. |last6=Petridou |first6=E. |year=1987 |title=The victims of Chernobyl in Greece: Induced abortions after the accident |journal=[[BMJ]] |volume=295 |issue=6606 |page=1100 |doi=10.1136/bmj.295.6606.1100 |pmc=1248180 |pmid=3120899}}</ref><ref name=pmid3585500>{{cite journal |last1=Ketchum |first1=Linda E. |title=Lessons of Chernobyl: SNM Members Try to Decontaminate World Threatened by Fallout |journal=Journal of Nuclear Medicine |volume=28 |issue=6 |pages=933–942 |year=1987 |pmid=3585500 |url=http://jnm.snmjournals.org/cgi/pmidlookup?view=long&pmid=3585500 |access-date=26 August 2016 |archive-date=5 March 2022 |archive-url=https://web.archive.org/web/20220305100443/https://jnm.snmjournals.org/content/28/6/933.long |url-status=live }}</ref><ref name="auto2">{{cite web |url=https://www.npr.org/2011/03/16/134585523/Chernobyls-Hot-Zone-Holds-Some-Surprises |title=Chernobyl's Hot Zone Holds Some Surprises |date=16 March 2011 |website=[[NPR]] |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20181108184718/https://www.npr.org/2011/03/16/134585523/Chernobyls-Hot-Zone-Holds-Some-Surprises |archive-date=8 November 2018 |url-status=live }}</ref><ref>{{cite web |url=http://health.phys.iit.edu/archives/2010-March/028156.html |title=Chernobyl-related abortions |last=Cedervall |first=Bjorn |date=10 March 2010 |website=RadSafe |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20161217112841/http://health.phys.iit.edu/archives/2010-March/028156.html |archive-date=17 December 2016 |url-status=live }}</ref> The statistical data excludes Soviet–Ukraine–Belarus abortion rates, which are unavailable. However, in Denmark, about 400 additional abortions were recorded, and in Greece, an increase of 2,500 terminations occurred despite the low radiation dose.<ref name="Knudsen">{{cite journal |last1=Knudsen |first1=L. B. |year=1991 |title=Legally-induced abortions in Denmark after Chernobyl |journal=Biomedicine & Pharmacotherapy |volume=45 |issue=6 |pages=229–231 |doi=10.1016/0753-3322(91)90022-L |pmid=1912378}}</ref><ref name="Trichopoulos"/>
No significant evidence of changes in the prevalence of congenital anomalies linked to the accident has been found in Belarus or Ukraine. In Sweden and Finland, studies found no association between radioactivity and congenital malformations.<ref name=pmid8516187>{{cite journal |doi=10.1111/j.1365-3016.1993.tb00388.x |pmid=8516187 |title=The Chernobyl accident, congenital anomalies and other reproductive outcomes |journal=Paediatric and Perinatal Epidemiology |volume=7 |issue=2 |pages=121–151 |year=1993 |last1=Little |first1=J.}}</ref> Larger studies, such as the EUROCAT database, assessed nearly a million births and found no impacts from Chernobyl. Researchers concluded that the widespread fear about the effects on unborn fetuses was not justified.<ref>{{cite journal |doi=10.1093/ije/28.5.941 |pmid=10597995 |title=Evaluation of the impact of Chernobyl on the prevalence of congenital anomalies in 16 regions of Europe. EUROCAT Working Group |journal=International Journal of Epidemiology |volume=28 |issue=5 |pages=941–948 |year=1999 |last1=Dolk |first1=H. |last2=Nichols |first2=R.|doi-access=free }}</ref>
The only robust evidence of negative pregnancy outcomes linked to the accident were the elective abortion effects due to anxiety
Studies on regions of Ukraine and Belarus suggest that around 50 children exposed in utero during weeks 8 to 25 of gestation may have experienced an increased rate of [[intellectual disability]] and lower verbal IQ.<ref>{{cite journal |doi=10.1155/2016/1243527 |pmid=27382490 |pmc=4921147 |title=Current Evidence for Developmental, Structural, and Functional Brain Defects following Prenatal Radiation Exposure |journal=Neural Plasticity |volume=2016 |pages=1–17 |year=2016 |last1=Verreet |first1=Tine |last2=Verslegers |first2=Mieke |last3=Quintens |first3=Roel |last4=Baatout |first4=Sarah |last5=Benotmane |first5=Mohammed A|doi-access=free }}</ref> The [[Chernobyl liquidators]] fathered children without an increase in developmental anomalies or a significant rise in [[germline mutation]]s
==== Cancer assessments ====
A report by the [[International Atomic Energy Agency]] examines the environmental consequences of the accident.<ref name="IAEA">{{cite book |url=http://www-pub.iaea.org/MTCD/publications/PDF/Pub1239_web.pdf |title=Environmental consequences of the Chernobyl accident and their remediation: Twenty years of experience. Report of the Chernobyl Forum Expert Group 'Environment' |publisher=International Atomic Energy Agency |year=2006 |isbn=978-92-0-114705-9 |location=Vienna, Austria |page=180 |access-date=13 March 2011 |archive-url=https://web.archive.org/web/20110409033554/http://www-pub.iaea.org/MTCD/publications/PDF/Pub1239_web.pdf |archive-date=9 April 2011 |url-status=live}}</ref> The [[United Nations Scientific Committee on the Effects of Atomic Radiation]] estimated a global [[collective dose]] from the accident equivalent to "21 additional days of world exposure to natural [[background radiation]]"; doses were far higher among 530,000 recovery workers
Estimates of deaths resulting from the accident vary greatly due to differing methodologies and data. In 1994, thirty-one deaths were [[Chernobyl disaster-related deaths|directly attributed to the accident]], all among reactor staff and emergency workers.<ref name="Hallenbeck 1994 15">{{cite book |title=Radiation Protection |last=Hallenbeck |first=William H. |isbn=978-0-87371-996-4 |publisher=CRC Press |year=1994 |quote=Reported thus far are 237 cases of acute radiation sickness and 31 deaths. |page=15}}</ref>
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The [[Chernobyl Forum]] revealed in 2004 that thyroid cancer among children was one of the main health impacts of the Chernobyl accident, due to ingestion of contaminated dairy products and inhalation of [[Iodine-131]]. More than 4,000 cases of childhood thyroid cancer were reported, but there was no evidence of increased solid cancers or leukemia. The WHO's Radiation Program reported nine deaths out of the 4,000 thyroid cancer cases.<ref name="ChernobylsLegacy">{{cite web |url=http://www.iaea.org/Publications/Booklets/Chernobyl/chernobyl.pdf |title=Chernobyl's Legacy: Health, Environmental and Socio-Economic Impacts |access-date=21 April 2012 |website=Chernobyl Forum |publisher=IAEA |url-status=dead |archive-url=https://web.archive.org/web/20100215212227/http://www.iaea.org/Publications/Booklets/Chernobyl/chernobyl.pdf |archive-date=15 February 2010 }}</ref> By 2005, UNSCEAR reported an excess of over 6,000 thyroid cancer cases among those exposed as children or adolescents.<ref name="Chernobyl health effects">{{cite web |url=http://www.unscear.org/unscear/en/chernobyl.html#Health |title=Chernobyl health effects |website=UNSCEAR.org |access-date=23 March 2011 |archive-url=https://web.archive.org/web/20110513235907/http://www.unscear.org/unscear/en/chernobyl.html#Health |archive-date=13 May 2011 |url-status=live }}</ref>
Well-differentiated thyroid cancers are generally treatable, with a five-year survival rate of 96% and 92% after 30 years.<ref>{{cite news |url=https://www.nytimes.com/2005/09/06/international/europe/06chernobyl.html |title=Experts find reduced effects of Chernobyl |last=Rosenthal |first=Elisabeth |date=6 September 2005 |newspaper=The New York Times |access-date=14 February 2008 |archive-url=https://web.archive.org/web/20130617213858/http://www.nytimes.com/2005/09/06/international/europe/06chernobyl.html |archive-date=17 June 2013 |url-status=live }}</ref> By 2011, UNSCEAR reported 15 deaths from thyroid cancer.<ref name=WHO2012/> The
The German affiliate of the [[International Physicians for the Prevention of Nuclear War]] suggests that 10,000 people have been affected by thyroid cancer as of 2006, with 50,000 cases expected in the future.<ref>{{cite web |title=20 years after Chernobyl, The ongoing health effects |website=[[IPPNW]] |date=April 2006 |access-date=24 April 2006 |url=http://www.ippnw-students.org/chernobyl/research.html |url-status=dead |archive-url=https://archive.today/20120629110109/http://www.ippnw-students.org/chernobyl/research.html |archive-date=29 June 2012 }}</ref>
==== Other disorders ====
Fred Mettler, a radiation expert, estimated 9,000 Chernobyl-related cancer deaths worldwide, noting that while small relative to normal cancer risks, the numbers are large in absolute terms.<ref name="Mettler">{{cite journal |last=Mettler |first=Fred |url=http://www.iaea.org/Publications/Magazines/Bulletin/Bull472/htmls/chernobyls_legacy2.html |title=Chernobyl's Legacy |journal=IAEA Bulletin |volume=47 |number=2 |access-date=20 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110805035918/http://www.iaea.org/Publications/Magazines/Bulletin/Bull472/htmls/chernobyls_legacy2.html |archive-date=5 August 2011 }}</ref> The report highlighted the risks to mental health from exaggerated radiation fears, noting that labeling the affected population as "victims" contributed to a sense of helplessness.<ref name="ChernobylsLegacy"/> Mettler also commented that 20 years later, the population remained unsure about radiation effects, leading to harmful behaviors.<ref name="Mettler
The [[United Nations Scientific Committee on the Effects of Atomic Radiation]] (UNSCEAR) has produced assessments of the radiation effects.<ref name=UNSCEAR>{{cite web |url=http://www.unscear.org/unscear/en/chernobyl.html |title=UNSCEAR assessment of the Chernobyl accident |website=United Nations Scientific Committee of the Effects of Atomic Radiation |access-date=31 July 2010 |archive-url=https://web.archive.org/web/20110513235907/http://www.unscear.org/unscear/en/chernobyl.html |archive-date=13 May 2011 |url-status=live }}</ref> Possibly due to the Chernobyl disaster, an unusually high number of cases of [[Down syndrome]] were reported in Belarus in January 1987, but there was no subsequent upward trend.<ref>{{Cite journal |url=https://pubmed.ncbi.nlm.nih.gov/17706919/ |title=Down syndrome time-clustering in January 1987 in Belarus: link with the Chernobyl accident? |date=2007 |pmid=17706919 |access-date=2024-02-07 |archiveurl=https://web.archive.org/web/20230515000000/https://pubmed.ncbi.nlm.nih.gov/17706919/ |archivedate=2023-05-15 |url-status= live |last1=Zatsepin |first1=I. |last2=Verger |first2=P. |last3=Robert-Gnansia |first3=E. |last4=Gagnière |first4=B. |last5=Tirmarche |first5=M. |last6=Khmel |first6=R. |last7=Babicheva |first7=I. |last8=Lazjuk |first8=G. |journal=Reproductive Toxicology (Elmsford, N.Y.) |volume=24 |issue=3–4 |pages=289–295 |doi=10.1016/j.reprotox.2007.06.003 |bibcode=2007RepTx..24..289Z }}</ref>
==== Long-term radiation deaths ====
The potential deaths from the Chernobyl disaster are heavily debated. The [[World Health Organization]] predicted 4,000 future cancer deaths in surrounding countries,<ref name="World Health Organization report ex"/> based on the [[Linear no-threshold model]] (LNT), which assumes that even low doses of radiation increase cancer risk proportionally.<ref>{{cite journal |doi=10.1001/archinternmed.2009.440 |title=Projected Cancer Risks from Computed Tomographic Scans Performed in the United States in 2007 |year=2009 |last1=Berrington De González |first1=Amy |author-link1=Amy Berrington de González |journal=Archives of Internal Medicine |volume=169 |issue=22 |pages=2071–2077 |pmid=20008689 |pmc=6276814 |last2=Mahesh |first2=M |last3=Kim |first3=KP |last4=Bhargavan |first4=M |last5=Lewis |first5=R |last6=Mettler |first6=F |last7=Land |first7=C}}</ref> The Union of Concerned Scientists estimated approximately 27,000 excess cancer deaths worldwide, using the same LNT model.<ref name="Union of Concerned Scientists">{{cite web |url=http://allthingsnuclear.org/post/4704112149/how-many-cancers-did-chernobyl-really-cause-updated |title=How Many Cancers Did Chernobyl Really Cause? |first=Lisbeth |last=Gronlund |author-link= Lisbeth Gronlund |date=17 April 2011 |website=Union of Concerned Scientists |access-date=8 November 2018 |archive-url=https://web.archive.org/web/20110421041043/http://allthingsnuclear.org/post/4704112149/how-many-cancers-did-chernobyl-really-cause-updated |archive-date=21 April 2011 |url-status=live }}</ref>
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[[File:Улица Кирова, Чернобыль.jpg|thumb|Abandoned buildings in Chernobyl]]
[[File:Ukrainian National Chornobyl Museum resembling the reactor that suffered the catastrophic failure (reactor core surrounded by blue) (8601829126).jpg|thumb|Exposition at [[Ukrainian National Chernobyl Museum]]]]
It is difficult to establish the total economic cost of the disaster. According to [[Mikhail Gorbachev]], the Soviet Union spent 18
Ongoing costs remain significant; in their 2003–2005 report, the [[Chernobyl Forum]] stated that between five and seven percent of government spending in Ukraine is still related to Chernobyl, while in Belarus, over $13
A significant impact was the removal of {{convert|784320|ha|acre|abbr=on}} of agricultural land and {{convert|694200|ha|acre|abbr=on}} of forest from production. While much has been returned to use, agricultural costs have risen due to the need for special cultivation techniques.<ref name="ChernobylsLegacy"/> Politically, the accident was significant for the new Soviet policy of [[glasnost]],<ref name="ShlyGlasnost">{{cite journal |doi=10.1080/00139157.1992.9931445 |title=Chernobyl and Glasnost: The Effects of Secrecy on Health and Safety |year=1992 |last1=Shlyakhter |first1=Alexander |last2=Wilson |first2=Richard |journal=Environment: Science and Policy for Sustainable Development |volume=34 |issue=5 |page=25|bibcode=1992ESPSD..34e..25S }}</ref> and helped forge closer Soviet–US relations at the end of the Cold War.<ref name="PetrynaLE"/>{{rp|44–48}} The disaster also became a key factor in the dissolution of the Soviet Union and shaped the 'new' [[Eastern Europe]].<ref name="PetrynaLE"/>{{rp|20–21}} Gorbachev stated that "More than anything else, (Chernobyl) opened the possibility of much greater freedom of expression, to the point that the (Soviet) system as we knew it could no longer continue."<ref>{{cite web |last=Gorbachev |first=Mikhail |date=21 April 2006 |title=Turning point at Chernobyl |url=https://www.japantimes.co.jp/opinion/2006/04/21/commentary/world-commentary/turning-point-at-chernobyl/}}</ref>
Some Ukrainians viewed the Chernobyl disaster as another attempt by Russians to destroy them, comparable to the [[Holodomor]].<ref>{{Cite book|last1=May|first1=Niels F.|url=https://books.google.com/books?id=EUcrEAAAQBAJ&q=%22Chernobyl%22+%22Holodomor%22&pg=PT211|title=National History and New Nationalism in the Twenty-First Century: A Global Comparison|last2=Maissen|first2=Thomas|date=17 June 2021|publisher=[[Routledge]]|isbn=9781000396348|quote=Members of the Ukrainian national movement regarded both Holodomor and Chernobyl as 'genocide against the Ukrainian people'.|access-date=27 August 2021|archive-date=12 September 2021|archive-url=https://web.archive.org/web/20210912223203/https://books.google.com/books?id=EUcrEAAAQBAJ&q=%22Chernobyl%22+%22Holodomor%22&pg=PT211|url-status=live}}</ref> Commentators have argued that the Chernobyl disaster was more likely to occur in a [[communist]] country than in a [[capitalist]] one.<ref>{{cite news |last1=Marlow |first1=Max |title=The tragedy of Chernobyl sums up the cruel failures of communism |url=https://www.telegraph.co.uk/politics/2019/06/09/tragedy-chernobyl-sums-cruel-failures-communism/ |archive-url=https://ghostarchive.org/archive/20220110/https://www.telegraph.co.uk/politics/2019/06/09/tragedy-chernobyl-sums-cruel-failures-communism/ |archive-date=10 January 2022 |url-access=subscription |url-status=live |newspaper=The Telegraph |date=9 June 2019 |publisher=The Telegraph (UK) |access-date=14 October 2021}}{{cbignore}}</ref> Soviet power plant administrators were reportedly not empowered to make crucial decisions during the crisis.<ref>{{cite web |last1=Plokhy |first1=Serhii |title=The Chernobyl Cover-Up: How Officials Botched Evacuating an Irradiated City |url=https://www.history.com/news/chernobyl-disaster-coverup |website=History.com |access-date=14 October 2021 |archive-date=19 October 2021 |archive-url=https://web.archive.org/web/20211019013138/https://www.history.com/news/chernobyl-disaster-coverup |url-status=live }}</ref>
== Significance ==
=== Nuclear debate ===
{{main|Nuclear power debate|nuclear power phase-out|anti-nuclear movement}}
[[File:Radiant Mayday-Demo after CHERNOBYL.jpg|thumb|Anti-nuclear protest after the Chernobyl disaster on [[international Workers' Day|May Day]], 1986 in [[West Berlin]]]]
The accident raised already heightened concerns about [[fission reactor]]s worldwide, and while most concern was focused on those of the same unusual design, hundreds of disparate nuclear reactor proposals, including those under construction at Chernobyl, reactors numbers 5 and 6, were eventually cancelled. With ballooning costs as a result of new [[nuclear reactor safety system]] standards and the legal and political costs in dealing with the increasingly hostile/anxious public opinion, there was a precipitous drop in the rate of new reactor construction after 1986.<ref>{{cite journal |url=https://www.iaea.org/sites/default/files/publications/magazines/bulletin/bull38-1/38104780209.pdf |last1=Juhn |first1=Poong-Eil |last2=Kupitz |first2=Juergen |title=Nuclear power beyond Chernobyl: A changing international perspective |journal=IAEA Bulletin |year=1996 |volume=38 |issue=1 |page=2 |access-date=13 March 2015 |archive-url=https://web.archive.org/web/20150508143703/https://www.iaea.org/sites/default/files/publications/magazines/bulletin/bull38-1/38104780209.pdf |archive-date=8 May 2015 |url-status=live }}</ref>
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The accident also raised concerns about the cavalier [[safety culture]] in the Soviet nuclear power industry, slowing industry growth and forcing the Soviet government to become less secretive about its operating procedures.<ref name=Kagarlitsky>{{cite book |title=The New Detente: Rethinking East-West Relations |chapter=Perestroika: The Dialectic of Change |last=Kagarlitsky |first=Boris |editor1-last=Kaldor |editor1-first=Mary |editor1-link=Mary Kaldor |editor2-last=Holden |editor2-first=Gerald |editor3-last=Falk |editor3-first=Richard A. |editor3-link=Richard A. Falk |year=1989 |publisher=United Nations University Press |isbn=978-0-86091-962-9}}</ref>{{efn|"No one believed the first newspaper reports, which patently understated the scale of the catastrophe and often contradicted one another. The confidence of readers was re-established only after the press was allowed to examine the events in detail without the original censorship restrictions. The policy of openness ([[glasnost]]) and 'uncompromising criticism' of outmoded arrangements had been proclaimed at the 27th Congress (of the [[Communist Party of Soviet Union]]), but it was only in the tragic days following the Chernobyl disaster that glasnost began to change from an official slogan into an everyday practice. The truth about Chernobyl that eventually hit the newspapers opened the way to a more truthful examination of other social problems. More and more articles were written about drug abuse, crime, corruption and the mistakes of leaders of various ranks. A wave of 'bad news' swept over the readers in 1986–87, shaking the consciousness of society. Many were horrified to find out about the numerous calamities of which they had previously had no idea. It often seemed to people that there were many more outrages in the epoch of [[perestroika]] than before although, in fact, they had simply not been informed about them previously." Kagarlitsky 1989, pp. 333–334.}} The government coverup of the Chernobyl disaster was a catalyst for [[glasnost]], which "paved the way for reforms leading to the Soviet collapse."<ref>{{cite news |title=Chernobyl cover-up a catalyst for glasnost |url=https://www.nbcnews.com/id/wbna12403612 |date=24 April 2006 |agency=Associated Press |website=[[NBC News]] |access-date=21 June 2015 |archive-url=https://web.archive.org/web/20150621102111/http://www.nbcnews.com/id/12403612/ns/world_news-europe/t/chernobyl-cover-up-catalyst-glasnost/ |archive-date=21 June 2015 |url-status=live }}</ref> Numerous structural and construction quality issues, as well as deviations from the original plant design, had been known to the KGB since at least 1973 and passed on to the [[Central Committee of the Communist Party of the Soviet Union|Central Committee]], which took no action and [[Classified information|classified]] the information.<ref>{{Cite web |last=Government Authorities or Not Fully Developed |date=12 June 2018 |title=Chornobyl nuclear disaster was tragedy in the making, declassified KGB files show {{!}} |url=http://euromaidanpress.com/2018/06/12/chernobyl-nuclear-plant-was-doomed-declassified-kgb-documents-reveal/ |url-status=live |archive-url=https://web.archive.org/web/20190618120916/http://euromaidanpress.com/2018/06/12/chernobyl-nuclear-plant-was-doomed-declassified-kgb-documents-reveal/ |archive-date=18 June 2019 |access-date=18 June 2019 |website=Euromaidan Press |language=en-US}}</ref>
In Italy, the Chernobyl accident was reflected in the outcome of the [[1987 Italian nuclear power referendum|1987 referendum]]. As a result
In Germany, the Chernobyl accident led to the creation of a [[German federal environment ministry|federal environment ministry]]
In direct response to the Chernobyl disaster, a conference to create a [[Convention on Early Notification of a Nuclear Accident]] was called in 1986 by the [[International Atomic Energy Agency]]. The resulting treaty has bound
===
{{Main|Cultural impact of the Chernobyl disaster}}
The Chernobyl tragedy has inspired many artists across the world to create works of art, animation, video games, theatre and cinema about the disaster. The HBO series ''[[Chernobyl (miniseries)|Chernobyl]]'' and the book ''[[Voices from Chernobyl]]'' by the Ukrainian-Belarusian writer [[Svetlana Alexievich]] are two well-known works
The video game [[S.T.A.L.K.E.R.: Shadow of Chernobyl|''S.T.A.L.K.E.R.: Shadows of Chernobyl'']] released by [[THQ]] in 2007, is a first-person shooter set in the [[Exclusion zone]].<ref>{{Cite web |title=S.T.A.L.K.E.R.: Shadow of Chernobyl |url=https://www.stalker-game.com/en/?page=gameplay |access-date=29 April 2022 |website=www.stalker-game.com}}</ref> A prequel called ''[[S.T.A.L.K.E.R.: Clear Sky]]'' was released in 2008 following with a sequel ''[[S.T.A.L.K.E.R.: Call of Pripyat]]'' released in 2010. Finally, the horror film ''[[Chernobyl Diaries]]'' released in 2012 is about six tourists that hire a tour guide to take them to the abandoned city of [[Pripyat]] where they discover they are not alone.<ref>{{Cite web |title=Chernobyl Diaries |url=https://www.boxofficemojo.com/release/rl1967883777/ |access-date=29 April 2022 |website=Box Office Mojo}}</ref>
[[Filmmaking|Filmmakers]] have created documentaries that examine the aftermath of the disaster over the years. Documentaries like the [[Oscar-winning]] ''[[Chernobyl Heart]]'' released in 2003, explore how radiation affected people living in the area and information about the long-term side effects of radiation exposure
== See also ==
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== External links ==
{{Sister project links|c=Category:Chernobyl disaster|d=yes|q=yes|n=no|s=no|b=no|v=no|voy=no|wikt=no|m=no|mw=no|species=no}}
* [https://web.archive.org/web/20080828234653/http://chernobyl.undp.org/ Official UN Chernobyl site]
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