How could the criticality excursion described below possibly cause a corner of the building roof to blow off and still have enough left in the tank to go critical again ?
The description below is of a VERY low yield burst ! (not unexpected, but inconsistent with that BBC video)
Jaro
frantaj@aecl.ca
----------
From: Michael C. Baker[SMTP:mcbaker@lanl.gov]
Reply To: radsafe@romulus.ehs.uiuc.edu
Sent: Thursday, September 30, 1999 5:03 PM
To: Multiple recipients of list
Subject: some details on the criticality in Japan
Here is some information that was sent to the criticality safety email list
on the accident in Japan.
Mike
>---------- Forwarded message ----------
>
>Toshihiro YAMAMOTO <yamamoto@melody.tokai.jaeri.go.jp> on 09/30/99
>11:10:41 AM
>
>To: VFDean@aol.com
>cc: Valerie L Putman/VPUTMAN/LMITCO/INEEL/US@INEL
>Subject: Re: Fwd: Possible Criticality in Japanese Fuel Reprocessing
> Facility(fwd)
>
>Dear colleague
>
>The following information are very preliminary ones and please
>keep in mind that those may be wrong.
>
>The accident was allegedly caused by putting more fuel
>into a tank than allowed (about 5 times ).
>The fuel is uranyl nitrate solution. The enrichment is
>18.8wt.% The concentration is approximately 370gU/l.
>The nitric acidity may be more than 1 mole/l.
>This fuel is for the test fast breeder reactor JOYO.
>
>The tank inner-diameter is 50 cm and 2.5cm-thickness water coolant is
>surrounding the tank at the side and the bottom. Approximately
>50 liter solution was poured in the tank, which means the solution
>height is approximately 25.5 cm. The tank wall thickness
>is 3 mm and made of stainless steel. My preliminary calculation
>gives keff=1.044 with MCNP and TWODANT. Exactly speaking,
>the bottom of the tank is slightly concave. But, detailed
>information is unknown.
>
>The criticality is probably continuing now even though
>the accident occurred more than 16 hours ago.
>
>If the water coolant is removed, the fuel may or may not be made
>subcritical (approximately keff=1.000).
>
>I hope this information is helpful for you.
>
>------------------------------------------
>Toshihiro YAMAMOTO
>Japan Atomic Energy Research Institute
>Dept. of Fuel Cycle Safety Research
>Criticality Safety Laboratory
>Phone:81-29-282-6743
>Fax: 81-29-282-6798
>E-mail:yamamoto@melody.tokai.jaeri.go.jp
>------------------------------------------
From: Susan Gawarecki[SMTP:loc@icx.net]
Reply To: radsafe@romulus.ehs.uiuc.edu
Sent: Thursday, September 30, 1999 4:42 PM
To: Multiple recipients of list
Subject: Nuclear accident in Japan -- BBC Video
The BBC video is accessible at the Yahoo site previously cited.
When I watched it, it appeared that a corner of a roof of one building
had been blown open. Perhaps a steam hammer was concentrated in the
corner of the room?
The BBC commentator also calls for more stringent building standards for
other uranium processing plants so that they can withstand small
"nuclear explosions." Up to that point the report seemed fairly
balanced and correct.
--