Re: some details on the criticality in Japan

[Thomas Gleich Harrison <tomh@jove.acs.unt.edu>]

Undoubtedly a steam/vapor powered explosion within an enclosed container.
If the Keff was estimated to be approx 1.044 it wouldn't take much of an
expulsion of material from the tank to reduce the Keff to less than one
and kill the fission process, which is probably what has happened. If the
fission process is continuing then much of the radiation yield might have
a detectable fast neutron component... which could be easily seen and
would probably be in a pulse mode if measured directly in the absence of
shielding. The residual radiation field is probably from fission product
decay I would think. Also usually the proximity of workers to a mixing
tank while in the process of a dump is not immediate ..... if the blast
was sufficient to remove a portion of a roof then death would probably
result from trauma injuries prior to radiation sickness if the workers
were the same distance from the tank.
 The tank cap may be what tore a hole in the roof...

just my opinion(s).....

Tom Harrison
RSO/Physics
University of North Texas
tomh@jove.acs.unt.edu

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