Editing Nuclear meltdown (section)

== China syndrome ==

{{See also|Core catcher}}
The '''China syndrome''' (loss-of-coolant accident) is a [[nuclear reactor]] operations accident characterized by the severe meltdown of the core components of the reactor, which then burn through the containment vessel and the housing building, then (figuratively) through the [[Crust (geology)|crust]] and [[Mantle (geology)|body]] of the Earth until reaching the opposite end, presumed to be in "China".<ref name="merriam-webster.com">{{cite dictionary|title=China Syndrome|url=http://www.merriam-webster.com/dictionary/china+syndrome|dictionary=Merriam-Webster|access-date=11 December 2012}}</ref><ref name=Raddatz2011>{{Cite episode| series = ABC World News| credits = Presenter: Martha Raddatz| network = ABC| airdate = 15 March 2011}}</ref> While the antipodes of China include Argentina with its [[Atucha Nuclear Power Plant]] the phrasing is metaphorical; there is no way a core could penetrate the several-kilometer thickness of the Earth's crust, and even if it did melt to the center of the Earth, it would not travel back upwards against the pull of gravity. Moreover, any tunnel behind the material would be closed by immense [[lithostatic pressure]].{{citation needed|date=September 2023}}

=== History ===

The [[Systems engineering|system design]] of the [[nuclear power plant]]s built in the late 1960s raised the concern that a severe reactor accident could release large quantities of [[radioactive material]]s into the atmosphere and environment. By 1970, there were doubts about the ability of the [[emergency core cooling system]] to cope with the effects of a [[loss of coolant accident]] and the consequent meltdown of the fuel core.<ref name="eleven"/> In 1971, in the article ''Thoughts on Nuclear Plumbing'', former Manhattan Project (1942–1946) nuclear physicist Ralph Lapp used the term "China syndrome" to describe a possible burn-through, after a loss of coolant accident, of the nuclear fuel rods and core components melting the containment structures, and the subsequent escape of [[Radioactivity|radioactive]] material(s) into the atmosphere and environment; the hypothesis derived from a 1967 report by a group of nuclear physicists, headed by W. K. Ergen.<ref name="Lapp, Ralph E 1971"/> In the event, Lapp’s hypothetical nuclear accident was cinematically adapted as ''[[The China Syndrome]]'' (1979).

The real scare, however, came from a quote in the 1979 film ''[[The China Syndrome]]'', which stated, "It melts right down through the bottom of the plant—theoretically to China, but of course, as soon as it hits ground water, it blasts into the atmosphere and sends out clouds of radioactivity. The number of people killed would depend on which way the wind was blowing, rendering an area the size of Pennsylvania permanently uninhabitable." The actual threat of this was coincidentally tested just 12 days after the release of the film when a meltdown at Pennsylvania's Three Mile Island Plant 2 ([[TMI-2]]) created a molten core that moved {{convert|15|mm|abbr=off}} toward "China" before the [[corium (nuclear reactor)|core froze]] at the bottom of the [[reactor pressure vessel]].<ref>{{Cite web |title=Safety of nuclear Power Reactors |url=http://npcil.nic.in/pdf/Safety_of_Nuclear_Power_Reactors.pdf |website=npcil.nic.in}}</ref> Thus, the TMI-2 reactor fuel and fission products breached the fuel rods, but the melted core itself did not break the containment of the reactor vessel.<ref>{{cite book|url=https://books.google.com/books?id=5X2Hxad9BoQC&pg=PT37|page=37|author=Gianni Petrangeli|title=Nuclear safety|publisher=Butterworth-Heinemann |year=2006 |isbn=0-7506-6723-0}}</ref>

A similar concern arose during the Chernobyl disaster. After the reactor was destroyed, a liquid [[corium (nuclear reactor)|corium]] mass from the melting core began to breach the concrete floor of the reactor vessel, which was situated above the bubbler pool (a large water reservoir for emergency pumps and to contain any steam pipe rupture). There was concern that a steam explosion would have occurred if the hot corium made contact with the water, resulting in more radioactive materials being released into the air. Due to damages from the accident, three station workers manually operated the valves necessary to [[Chernobyl disaster#Bubbler_pools|drain this pool]].<ref>Andrew Leatherbarrow ''Chernobyl 01:23:40''</ref><ref>{{cite web |title=Воспоминания старшего инженера-механика реакторного цеха №2 Алексея Ананенка |trans-title=Memoirs of the senior engineer-mechanic of reactor shop №2 Alexey Ananenko |url=http://www.souzchernobyl.org/?id=2440 |url-status=live |archive-url=https://web.archive.org/web/20181108224413/http://www.souzchernobyl.org/?id=2440 |archive-date=8 November 2018 |access-date=8 November 2018 |website=Exposing the Chornobyl Myths |language=ru}}</ref><ref>{{cite web |date=16 April 2005 |title=Человек широкой души: Вот уже девятнадцатая годовщина Чернобыльской катастрофы заставляет нас вернуться в своих воспоминаниях к апрельским дням 1986 года |trans-title=A man of broad souls: The nineteenth anniversary of the Chernobyl catastrophe forces us to return to our memories of the April days of 1986 |url=http://www.postchernobyl.kiev.ua/pamyati-tovarishha/ |url-status=dead |archive-url=https://web.archive.org/web/20160426031626/http://www.postchernobyl.kiev.ua/pamyati-tovarishha/ |archive-date=26 April 2016 |access-date=3 May 2016 |website=Post Chernobyl |language=ru}}</ref> However, this concern was proven to be unfounded as (unknown to those at the time) the corium already contacted the reservoir before it could be drained, where instead of creating a steam explosion it harmlessly cooled rapidly and created a light-brown ceramic pumice that floated on the water.