Re: JAPANESE CRITICALITY

["Bjorn Cedervall" <bcradsafers@hotmail.com>]

>Forgive me if I haven't been paying attention, but has there been any
>new developments re determining doses to the three injured workers?

I think that we are many who wonder the same thing. The following sentence 
(just forwarded by Tosh Ushino - thank you once more for the valuable 
information you give us) casts some ideas about the dose questions: "The 
most seriously injured man was holding the funnel for the uranium as it was 
being poured into the tank, getting hit by about 1,700 rads, a measure of 
absorbed radiation, Mettler said."

The inverse square law becomes important when the distance to the source is 
small (say less than about 1 m (3-4 feet)). If Mr. A was holding a funnel 
(=being very close to the source) for the uranium the dose was probably very 
different for different parts of his body - (a factor of at least say 5-10 
would be possible - or what do you other Radsafers say?). The actual body 
position (bent vs. standing up, straight arms or not etc) should reasonably 
also be of high relevance for the dose distribution in an accident like 
this.

As we read earlier, the dose was determined from neutron activated metal 
materials (coins and other items) and also from the "body" level of sodium 
24. The latter should reasonably be a weighted average due to the exposure. 
Then there is a question of the dose ratio "neutron/gamma" - what could the 
uncertainty be in the estimates? Please comment or correct with anything 
more solid.

My own thoughts only,

Bjorn Cedervall   bcradsafers@hotmail

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