Editing Three Mile Island accident (section)

== Kemeny Commission ==
Several state and federal government agencies mounted investigations into the crisis, the most prominent of which was the ''President's Commission on the Accident at Three Mile Island'', created by U.S. President [[Jimmy Carter]] in April 1979.<ref>{{cite book |last=Walker |first=J. Samuel |url=https://archive.org/details/threemileislandn00walk/page/209/mode/1up |title=Three Mile Island: A Nuclear Crisis in Historical Perspective |date=2004 |publisher=University of California Press |isbn=0-520-23940-7 |location=Berkeley, CA |pages=209–210 |quote=The Three Mile Island crisis was quickly followed by several extensive investigations. The NRC, the state of Pennsylvania, congressional committees, and nuclear industry groups sponsored important studies, but the most prominent of the inquiries were conducted by the President's Commission on the Accident at Three Mile Island. In a speech to the nation about energy policies on April 5, 1979, President Carter announced that he would create an independent commission "to investigate the causes" of Three Mile Island and "to make recommendations on how to improve the safety of nuclear power plants." Six days later he formally established the commission and identified eleven persons he had appointed to it (a twelfth was added a short time later). The projected cost of the study was about $1 million. The White House deliberately avoided placing anyone on the panel who was associated with strong pro- or antinuclear views. |access-date=October 25, 2021}}</ref> The commission consisted of a panel of 12 people, specifically chosen for their lack of strong pro- or anti-nuclear views, and headed by chairman [[John G. Kemeny]], president of [[Dartmouth College]]. It was instructed to produce a final report within six months, and after public hearings, depositions, and document collection, released a completed study on October 31, 1979.<ref>{{cite book |last=Walker |first=J. Samuel |url=https://archive.org/details/threemileislandn00walk/page/210/mode/1up |title=Three Mile Island: A Nuclear Crisis in Historical Perspective |date=2004 |publisher=University of California Press |isbn=0-520-23940-7 |location=Berkeley, California |pages=210 |language=en-us |quote=The Kemeny Commission operated under stringent time constraints. The president instructed it to submit a final report on Three Mile Island within six months after its first meeting. The commission conducted its investigation by assigning staff members and consultants to task forces that examined technical issues, the roles of the NRC and Met Ed, emergency preparedness, public information, and health effects. After holding a series of public hearings, taking more than 150 depositions, and collecting about three hundred cubic feet of documents, it presented its findings to Carter on October 30, 1979, and released them to the public the following day. The completed study consisted of a 179-page overview and nine volumes of task force reports that totaled more than 2,200 pages. |access-date=October 25, 2021}}</ref>

According to the official figures, as compiled by the 1979 Kemeny Commission from Met Ed and NRC data, a maximum of {{convert|480|PBq|MCi|abbr=on}} of radioactive noble gases, primarily [[xenon]], were released by the event.<ref name="Walker231">{{cite book |last=Walker |first=J. Samuel |url=https://archive.org/details/threemileislandn00walk/page/231/mode/1up |title=Three Mile Island: A Nuclear Crisis in Historical Perspective |date=2004 |publisher=University of California Press |isbn=0-520-23940-7 |location=Berkeley, California |pages=231 |language=en-us |quote=Another significant question that the cleanup of the containment building raised was why more radioactive iodine had not escaped from the plant. Although the accident discharged up to 13 million curies of radioactive noble gases to the environment, it released very little of the much more hazardous iodine-131. A curie is a unit of measurement formerly used to indicate the decay rate (or level of activity) of radioactive substances. Of the estimated 64 million curies of iodine-131 in the core at the time of the accident, less than 20 curies leaked to the atmosphere. This was a far smaller release of iodine-131 than reactor experts had postulated in projecting the consequences of a severe reactor accident before Three Mile Island. Researchers found that most of the iodine-131 in the core had combined with other elements to form compounds that dissolved in water or had attached to metal surfaces in the containment building. Under the conditions in the core and the reactor building, the iodine did not remain in a gaseous state long enough to escape from the plant into the environment. |access-date=October 25, 2021}}</ref> These noble gases were considered relatively harmless, and only {{convert|481|-|629|GBq|Ci|abbr=on}} of [[thyroid cancer]]-causing [[iodine-131]] were released.<ref name="Walker231" /> Total releases according to these figures were a relatively small proportion of the estimated {{convert|370|EBq|GCi|abbr=on}} in the reactor. It was later found that about half the core had melted, and the cladding around 90% of the fuel rods had failed,<ref name="FactSheet" /><ref>Kemeny, p. 30.</ref> with {{convert|5|ft|m|1|abbr=on}} of the core gone, and around {{convert|20|ST|t|lk=on|abbr=on}} of uranium flowing to the bottom head of the pressure vessel, forming a mass of [[Corium (nuclear reactor)|corium]].<ref>{{cite journal |last1=McEvily |first1=A. J. Jr. |last2=Le May |first2=I. |year=2002 |title=The Accident at Three Mile Island |url=https://www.jstage.jst.go.jp/article/jsms1963/51/3Appendix/51_3Appendix_1/_pdf |journal=Materials Science Research International |volume=8 |issue=1 |pages=1–8}}</ref> The reactor vessel—the second level of containment after the cladding—maintained integrity and contained the damaged fuel with nearly all of the radioactive isotopes in the core.<ref name="ANS">{{cite web |url=http://www.ans.org/pi/resources/sptopics/tmi/whathappened.html |access-date=November 9, 2008 |title=What Happened and What Didn't in the TMI-2 Accident |website=[[American Nuclear Society]] |url-status=dead |archive-url=https://web.archive.org/web/20110717080337/http://www.touchoilandgas.com/ebooks/A1ioj0/eandpvol7iss2/resources/134.htm |archive-date=July 17, 2011}}{{Verify source|type=archive|date=April 2019}}</ref>

Anti-nuclear political groups disputed the Kemeny Commission's findings, claiming that other independent measurements provided evidence of radiation levels up to seven times higher than normal in locations hundreds of miles downwind from TMI.<ref name="Mangano2004">{{cite journal |last=Mangano |first=Joseph |date=September–October 2004 |title=Three Mile Island: Health Study Meltdown |url=https://journals.sagepub.com/doi/pdf/10.2968/060005010 |journal=[[Bulletin of the Atomic Scientists]] |volume=60 |issue=5 |pages=30–35 |doi=10.2968/060005010 |s2cid=143984619 |issn=0096-3402}}</ref> [[Arnold Gundersen|Arnie Gundersen]], a former nuclear industry executive and anti-nuclear advocate,<ref>{{cite web |url=http://fairewinds.com/content/who-we-are |title=Who We Are |website=Fairewinds Associates, Inc |archive-url=https://web.archive.org/web/20100517022024/http://fairewinds.com/content/who-we-are |archive-date=May 17, 2010 |access-date=March 17, 2012 |url-status=dead}}</ref> said "I think the numbers on the NRC's website are off by a factor of 100 to 1,000".<ref name="sturgis09">{{cite web |last=Sturgis |first=Sue |url=https://www.facingsouth.org/2009/04/investigation-revelations-about-three-mile-island-disaster-raise-doubts-over-nuclear-plant-s |title=Investigation: Revelations about Three Mile Island disaster raise doubts over nuclear plant safety |date=April 2, 2009 |website=The Institute for Southern Studies |url-status=dead |archive-url=https://web.archive.org/web/20160814210605/https://www.facingsouth.org/2009/04/investigation-revelations-about-three-mile-island-disaster-raise-doubts-over-nuclear-plant-s |archive-date=August 14, 2016 |access-date=September 4, 2016 |quote=Arnie Gundersen—a nuclear engineer and former nuclear industry executive turned whistle-blower—has done his own analysis, which he shared for the first time at a symposium in Harrisburg last week. "I think the numbers on the NRC's website are off by a factor of 100 to 1,000," he said.}}</ref>{{Verify source|date=April 2019}}<ref>{{cite web |url=http://www.southernstudies.org/images/sitepieces/ThompsonTMIassessment.pdf |title=TMI Assessment (Part 2) – Releases of radiation to the environment |last1=Thompson |first1=Randall |last2=Bear |first2=David |year=1995 |website=The Institute for Southern Studies |archive-url=https://web.archive.org/web/20160416090620/http://www.southernstudies.org/images/sitepieces/ThompsonTMIassessment.pdf |archive-date=April 16, 2016 |url-status=dead |access-date=September 4, 2016}}</ref> Gundersen offers evidence, based on pressure monitoring data, for a hydrogen explosion shortly before 2:00&nbsp;p.m. on March 28, 1979, which would have provided the means for a high dose of radiation to occur. Gundersen cites affidavits from four reactor operators according to which the plant manager was aware of a dramatic pressure spike, after which the internal pressure dropped to outside pressure. Gundersen also claimed that the control room shook and doors were blown off hinges. However, official NRC reports refer merely to a "hydrogen burn".<ref name="sturgis09" />{{Verify source|date=April 2019}}

The Kemeny Commission referred to "a burn or an explosion that caused pressure to increase by {{convert|28|psi}} in the containment building",<ref name="PresidentsCommission">{{cite web |last=Kemeny |first=John G. |title=Report of The President's Commission On The Accident at Three Mile Island: The Need For Change: The Legacy Of TMI |url=http://www.threemileisland.org/downloads//188.pdf |display-authors=etal |website=ThreeMileIsland.org |date=October 1979 |access-date=September 30, 2018 |url-status=usurped |archive-url=https://web.archive.org/web/20120401001407/http://www.threemileisland.org/downloads//188.pdf |archive-date=April 1, 2012}}</ref> while ''[[The Washington Post]]'' reported that "At about 2:00&nbsp;pm, with pressure almost down to the point where the huge cooling pumps could be brought into play, a small hydrogen explosion jolted the reactor."<ref>{{cite news |title=The Tough Fight to Confine the Damage |url=https://www.washingtonpost.com/wp-srv/national/longterm/tmi/stories/ch4.htm |newspaper=The Washington Post |year=1979 |access-date=September 30, 2018}}</ref> Work performed for the Department of Energy in the 1980s determined that the hydrogen burn ([[deflagration]]), which went essentially unnoticed for the first few days, occurred 9 hours and 50 minutes after initiation of the accident, had a duration of 12 to 15 seconds and did not involve a [[detonation]].<ref>{{cite report |url=https://digital.library.unt.edu/ark:/67531/metadc1108164/m2/1/high_res_d/6237032.pdf |title=Lessons Learned From Hydrogen Generation and Burning During The TMI-2 Event |last1=Henrie |first1=J. O. |last2=Postma |first2=A. K. |date=May 1987 |publisher=U.S. Department of Energy, Hanford Office |page=2-1 |docket=DOE Contract No. DE-AC06-77RL01030 |quote=The hydrogen burn occurred throughout essentially all of the 2,033,000 ft3 (57,600 m3) containment during a period of approximately 12 s. Less than 5% of the burning took place in the first 6 s, less than 40% during the next 3 s, and more than half of the burning occurred during the last 3 s. There was no detonation. The hottest gas was the gas that burned at approximately 6 s prior to the end of the burn. Even though the gas was losing heat to the unburned gas and surrounding surfaces after it burned, compression heating was dominant and significantly increased its temperature until the pressure peaked. |access-date=October 9, 2021}}</ref><ref>{{cite report |url=https://digital.library.unt.edu/ark:/67531/metadc1204546/m2/1/high_res_d/6312264.pdf |title=Analysis of the Three Mile Island Unit 2 Hydrogen Burn |last1=Henrie |first1=J. O. |last2=Postma |first2=A. K. |date=March 1983 |publisher=U.S. Department of Energy, Hanford Office |volume=4 |page=iii |docket=DE-AV07-76IDO1570 |quote=Prior to the burn (deflagration), the hydrogen was well mixed with the containment air. The average hydrogen concentration was calculated to be 7.9%, wet basis. The hydrogen burn occurred at all three levels in the containment. The burn was initiated somewhere in the lowest level; probably on the west side. Even though the burn time was about 15 sec, nearly all of the burning occurred during a 6-sec period. Over one-half of the burning occurred during the last 3-sec period. |access-date=October 9, 2021}}</ref>

The investigation strongly criticized [[Babcock & Wilcox]], Met Ed, General Public Utilities, and the NRC for lapses in quality assurance and maintenance, inadequate operator training, lack of communication of important safety information, poor management, and complacency, but avoided drawing conclusions about the future of the nuclear industry.<ref>{{cite book |last=Walker |first=J. Samuel |url=https://archive.org/details/threemileislandn00walk/page/210/mode/1up |title=Three Mile Island: A Nuclear Crisis in Historical Perspective |date=2004 |publisher=University of California Press |isbn=0-520-23940-7 |location=Berkeley, California |pages=210 |language=en-us |quote=The commission offered a harsh indictment of Babcock & Wilcox, Met Ed, GPU, and the NRC. It explained that it had no mandate to draw conclusions about the future of the nuclear industry or to make comparisons of nuclear power with other sources of energy. It did not intend to show either that "nuclear power is inherently too dangerous to permit it to continue and expand" or that "the nation should move forward aggressively to develop additional commercial nuclear power." Rather, the commission suggested "that if the country wishes, for larger reasons, to confront the risks that are inherently associated with nuclear power, fundamental changes are necessary if those risks are to be kept within tolerable limits." It maintained that critical improvements in reactor safety required major revisions, if not a revolution, in organization, practices, procedures, and above all, the "mindset" of the nuclear industry and the NRC. |access-date=October 25, 2021}}</ref> The heaviest criticism from the Kemeny Commission said that "... fundamental changes will be necessary in the organization, procedures, and practices—and above all—in the attitudes" of the NRC and the nuclear industry.<ref>{{cite book |last=Kemeny |first=John J |url=https://www.hsdl.org/?view&did=769775 |title=Report of the Commission on The Accident at Three Mile Island—The Need For Change: The Legacy of TMI |date=October 1979 |publisher=U.S. Government Printing Office |isbn=978-1297534478 |location=Washington, D.C. |page=7 |chapter=Overall Conclusion |quote=To prevent nuclear accidents as serious as Three Mile Island, fundamental changes will be necessary in the organization, procedures, and practices—and above all—in the attitudes of the Nuclear Regulatory Commission and, to the extent that the institutions we investigated are typical, of the nuclear industry. |access-date=October 25, 2021}}</ref> Kemeny said that the actions taken by the operators were "inappropriate" but that the workers "were operating under procedures that they were required to follow, and our review and study of those indicates that the procedures were inadequate" and that the control room "was greatly inadequate for managing an accident".<ref>{{cite web |year=1979 |title=Three Mile Island – 1979 Year in Review |url=http://www.upi.com/Audio/Year_in_Review/Events-of-1979/Three-Mile-Island/12311692377023-3/ |access-date=March 6, 2018 |work=United Press International}}</ref>

The Kemeny Commission noted that Babcock & Wilcox's PORV had previously failed on 11&nbsp;occasions, nine of them in the open position, allowing coolant to escape. The initial causal sequence of events at TMI had been duplicated 18&nbsp;months earlier at another Babcock & Wilcox reactor, the [[Davis–Besse Nuclear Power Station]]. The only differences were that the operators at Davis–Besse identified the valve failure after 20&nbsp;minutes, where at TMI it took 80 minutes, and the fact that the Davis–Besse facility was operating at 9% power, against TMI's 97%. Although Babcock engineers recognized the problem, the company failed to clearly notify its customers of the valve issue.<ref>{{cite journal |last=Hopkins |first=A. |year=2001 |title=Was Three Mile Island a 'normal accident'? |volume=9 |issue=2 |pages=65–72 |doi=10.1111/1468-5973.00155 |newspaper=Journal of Contingencies and Crisis Management}}</ref>

The [[Pennsylvania House of Representatives]] conducted its own investigation, which focused on the need to improve evacuation procedures.{{citation needed|reason=Source needed|date=November 2016}}

In 1985, a television camera was used to see the interior of the damaged reactor. In 1986, [[core sample]]s and samples of debris were obtained from the [[Corium (nuclear reactor)|corium]] layers on the bottom of the reactor vessel and analyzed.<ref>{{cite journal |last1=Akers |first1=D. W. |last2=Jensen |first2=S. M. |last3=Schuetz |first3=B. K. |date=March 1, 1994 |title=Examination of relocated fuel debris adjacent to the lower head of the TMI-2 reactor vessel |url=http://www.osti.gov/bridge/product.biblio.jsp?osti_id=10140801 |doi=10.2172/10140801 |access-date=March 6, 2018 |doi-access=free |website=Department of Energy, Office of Scientific and Technical Information}}</ref>