Re: Of interest to Indian Point and EP folk.

[Bernard L Cohen <blc+@pitt.edu>]

On Sat, 8 Apr 2000, D. Kosloff wrote:
> 
> 1)  In an average meltdown (ie. in a majority of plausible scenarios in
> which there is a serious accident), what is the likely time it will take for
> an area to become so hot that people will be dying from exposure  (ie. dying
> directly, not from developing cancer over the following  years)?

	--In an average meltdown, essentially no radiation exposure to
those outside occurs because of the containment. If this fails, there is a
wide spectrum of health impacts, but, according to the PRAs, in only one
meltdown in 50 are there any early deaths from radiation sickness. In 0.2%
of meltdowns, there would be as many as 100 eearly deaths. The time it
takes for the contamination to reach near its maximum would be very short
after a containment failure -- probably minutes, or a few hours at most. 

> 
> 2) In an average meltdown (ie. in a majority of plausible scenarios in which
> there is a serious accident), what is the likely radius that will  need to
> be evacuated?  What percentage of serious accidents would  require
> evacuation of an area of greater than a 20 mile radius from the  plant?
>
	--If the containment holds for several hours, there would be no
need for evacuation. In about 1% of meltdowns, an area of 30 miles radius
would be temporarily evacuated, and an area of 10 mile radius would be
"permanently" evacuated, according to WASH-1400


> 3)  For the accident in Chernobyl, what distance from the plant needed to be
> evacuated (radius in miles) and how long did it take for the area near the
> plant to become so hot that people were dying from exposure  (ie. dying
> directly, not from developing cancer over the following  years)?"
> 
	--no one died or suffered radiation sickness from living near the
plant. The releases there continued for several days as the graphite fire
continued to burn - this would not apply in U.S. type reactors. Largest
exposures, averaging 50 rem, were received at 2-6 miles away - again this
is because of the fire which propelled the radioactivity high into the
air, which would not be applicable in U.S. reactors. Evacuations were
carried out for those living up to 18 miles away. For those living 9-18
miles away, average doses were 5 rem.

Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


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