Fuel meltdown incidents

The total number of immediate deaths attributable directly to these incidents over 35 or more years of nuclear reactor operation is less than 35—three at a military prototype reactor in 1981 in the USA and 31 at Chernobyl. However, three subsequent deaths have been reported at Chernobyl (see Appendix 7). Of the fuel meltdown incidents (excluding Chernobyl-4), eight relatively serious incidents have been selected and subjected to some analysis in the following subsection. It is noted that, of these fuel meltdown incidents, only one (Three Mile Island-2) was at an operating, fully developed power plant. All of the other incidents involved research reactors or developmental or prototype plant. Three relatively minor incidents are also reviewed where single channel fuel overheating occurred in graphite-moderated plant. 

The following descriptions of the incidents are deliberately brief. More detailed descriptions are available, for example in the sources listed on p. 8. 

Reactor. Heavy water moderated research reactor. 

Inadvertent withdrawal of control rods, leading to core melting, formation of hydrogen and a chemical explosion. 

Initiation. Communication misunderstanding instrumentation indication error Scram did not function. 

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Fuel meltdown incident has occurred in Fermi due to blockage of subassembly at inlet and at EBRI due to inward bowing of core subassemblies. 

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