RE: some details on the criticality in Japan

["Gene Rollins" <erollins@hacom.net>]

The doses received by 2 individuals has been described in the news media as
"2,000 times the legal annual limit."  This would imply a dose in the 100 Sv
range.  At this dose level, the individuals might survive 1 or 2 days.
However, I question their ability to ascertain the actual absorbed dose with
any accuracy so quickly.

Eugene M. Rollins
erollins@hacom.net

> -----Original Message-----
> From: radsafe@romulus.ehs.uiuc.edu
> [mailto:radsafe@romulus.ehs.uiuc.edu]On Behalf Of g2v13a@swbell.net
> Sent: Friday, October 01, 1999 9:05 AM
> To: Multiple recipients of list
> Subject: Re: some details on the criticality in Japan
>
>
> Greetings,
>
> May I ask for some information that may help some of us
> understand the doses
> better.  (I am mostly involved in total body irradiation for leukemia ...)
> In medical TBI treatments a beam of 6-10 MV x-rays is used with doses of
> 250-300 cGy are commonly given (split between two exposures) per day to a
> total of between 900 - 1200 cGy (depending upon institutional
> preferences).
> Based upon my observations of these patients over the years, I am
> suprized to
> be hearing that 6-8 Sv in one exposure of less than one hour can
> cause death
> within 6 hours or severe cns (etc.) symptoms within 8 hours.
> Admittedly, I
> have dealt only in fractionated x-ray (medical) exposures.  My
> questions are
> (for this type of event) :
> 1) What is the likely dose to the three persons described in the media
> reports ?
> (6-8 Sv does not seem to be consistant with the reported symptoms.)
> 2) What are the likely photon and neutron dose components ?
> 3) What is the likely "x-ray" equivalent photon spectra ?
> 4) What is the likely neutron energy distribution ?
>
> Just a "medical-type" trying to better understand a non-medical
> type event.
>
> Doug J.
> ------------------------------------------------------------
> Thomas Gleich Harrison wrote:
>
> > 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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