Dispersal of Spent Fuel -Reply

[Charles Willis <CAW@nrc.gov>]

John Harvey asked "what happens to a spent MTR fuel element when exploded."  I do not
believe that data have been generated to answer that question, largely because there has
been no concern about the explosion of a MTR fuel element.  Accidental out-of-core criticality
is possible, of course, but the fuel element would not explode.   If a fuel element is overheated,
by whatever mechanism, some of its radioactive material can be released.  It the mechanism
were accidental criticality, however, the available evidence indicates that the direct radiation
would be the dominant radiological hazard.  I wonder what scenario gives rise to the question.