Re: 20 mSv/a - 17 Sv/min - Chernobyl

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

On Sat, 9 Oct 1999, Dolf Brits wrote:
> 
> It has been stated in the paper that "low doses of radiation caused a much
> larger risk of cancer than expected from the linear model". The (only)
> researcher on this topic mentioned by name is Wolfgang Kohnlein who "argued
> that the actual risks of radiation exposure may be 20 times higher than
> predicted by the linear model".

	Kohnlein represents only a tiny segment of the radiation health
effects community. A very much larger segment believes the opposite, that
actual risks are very much smaller than predicted by linear-no threshold
theory.
	The Kohnlein papers I know about are highly theoretical, and give
no cosideration to effects of radiation on the body's biological defense
mechanisms. There is a wide range of evidence indicating that these are
stimulated by low level radiation, which would reduce the net risk or even
make it negative (hormesis).




> 
> Should we now plan for a future lowering of dose limits ?
> 
> 
> 2. 17 Sv/min
> 
> This may be the approximate dose rate that the unfortunate Japanese worker
> was exposed to.
> Hopefully he is still alive.
> Now how do you explain spending money on a 20 mSv/a dose limit to a miner
> who faces extremely though (and lethal) working conditions. ?
> The person that received 1000 times the dose (in about a minute), against
> which the miner is protected over a year, is not killed instantly.
> 100 mSv accrued while working in a mine subjects the miner to a
> non-quantifiable (small) risk (the HPS position statement ?).
> 
> How does all this add up?
> 
> 
> 3. Chernobyl deaths
> 
> a). As it happens our "Business Report", which alerted us to the mining
> issue, also carried an article on nuclear energy - South Africa is currently
> developing an intrinsically safe helium-cooled reactor. In this highly
> reliable newspaper, our "mining journalist" also states that
> "Chernobyl....caused an estimated 25 000 deaths from cancer".
> 
> b). The Chernobyl report of the NEA Committee of the OECD (Nov 1995) refers
> to 31 dead (p.12), a significant increase in carcinomas (no deaths ?) among
> children (p.13) and not even "any increase in cancers" (p13) in the
> population. This population however received significant doses - 120 people
> received more than 200 mSv during 1986-89 (p. 51).
> 
> c). According to the Ukraine's ambassador, the "Chernobyl disaster killed 4
> 229 people" as reported on
> http://www.chernobyl.com/health.htm.
> 
> How many Chernobyl deaths ?
> 
> Taking a geometric average (to give some credence to NEA Committee) yields 1
> 485 deaths.
> There must be a better estimate ?
> 
> Thank you for your trouble
> 
> Dolf Brits
> South Africa
> 
> dbrits@mepta.pwv.gov.za
> 
> 
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> 
Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu



************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html