Nuclear meltdown derived from a 1967 report by a group of nuclear physicists, headed by W. K. Ergen. In the event, Lapp’s hypothetical nuclear accident was cinematically adapted as "The China Syndrome" (1979). Nuclear meltdown A nuclear meltdown (core melt accident or partial core melt) is a severe nuclear reactor accident that results in core damage from overheating. The term "nuclear meltdown" is not officially defined by the International Atomic Energy Agency or by the Nuclear Regulatory Commission. However, it has been defined to mean the accidental melting of the core of a nuclear reactor, and is in common usage a reference
Natural nuclear fission reactor the time the reactor went critical 1.7 billion years ago, the fissile isotope made up about 3.1% of the natural uranium, which is comparable to the amount used in some of today's reactors. (The remaining 96.9% was non-fissile .) Because has a shorter half-life than , and thus decays more rapidly, the current abundance of in natural uranium is about 0.70–0.72%. A natural nuclear reactor is therefore no longer possible on Earth without heavy water or graphite. The Oklo uranium ore deposits are the only known sites in which natural nuclear reactors existed. Other rich uranium ore bodies would also