[ RadSafe ] From Wikipedia under Prompt Critical Event

Roger Helbig rhelbig at sfo.com
Sat Apr 30 20:53:06 CDT 2011

Gundersen has quickly spread into Wikipedia as follows -



With the exception of research and experimental reactors, only three reactor
accidents are suspected of having achieved prompt criticality, those of
Chernobyl #4 <http://en.wikipedia.org/wiki/Chernobyl_disaster> , the U.S.
Army's SL-1 <http://en.wikipedia.org/wiki/SL-1> , and Soviet submarine K-431
<http://en.wikipedia.org/wiki/Soviet_submarine_K-431> . In some cases there
is doubt that prompt criticality occurred, although the uncontrolled surge
in power was sufficient to cause an explosion that destroyed each reactor
and caused a release of radioactive
<http://en.wikipedia.org/wiki/Radioactive>  fission products
<http://en.wikipedia.org/wiki/Fission_product>  into the atmosphere. In
addition, a prompt criticality has been postulated in the
<http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents>  for the 13 Mar
2011 explosion at the spent fuel pool located on top of the reactor in Unit
3. The American nuclear engineer Arnold Gundersen
<http://en.wikipedia.org/wiki/Arnold_Gundersen>  theorized that a smaller
hydrogen gas explosion caused mechanical disruption of spent fuel pool
material triggering a prompt criticality.
<http://en.wikipedia.org/wiki/Prompt_critical#cite_note-1> [2]

Is this hypothesis by Gundersen supported by any actual evidence or is this
just hype that has spread into the Wikipedia?   If it is not a valid
hypothesis, suggest that someone edit this Wikipedia article and correct it.


Roger Helbig

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