Re: 4x Re: Supplemental Radilogical Criteria

["J. J. Rozental" <josrozen@netmedia.net.il>]

The effectiove dose of 0.01 mSv/a expected to be incurred by any member of
the public is necessary condition   for  exemption and clearance, however,
according with the Basic Safety Standards IAEA 115, 1996, provided also
either  the collective effective dose commited by one year of the
performance of the practice is no more than about 1 man.Sv or an assessment
for the o[ptimization of protection shows that exemption is the optimum option.

Considering your own example: "For example, you will derive values of a few
Bq/g (Co-60) for the recycling of scrap or debris (under real conditions).
This is something you can measure and you can release!"

The exemption for Co-60, according with the BSS-115 is 10 Bq/g
(concentration)     or 10E5 Bq, however the unconditional clearance  for
Co-60  according with the Clearance Levels for Radionuclides in solid
materials, IAEA TECDOC 855, January 1966, is in  the range of 0-1 to 1 Bq/g,
averaged 0.3 Bq/g. 
The above TECDOC mention,  page 48: "Of the practice considered, the largest
collective doses may be expected to arise from recycling of steel and others
metals, specially if metal were to be recycled into consumer goods or into
motor cars with which humans may come into close contact during their normal
use."
"In case of Co-60, which seems likely to be    the most important
radionuclide in the context of steel recycling and collective dose, the
estimated annual recycled quantity which could give rise to 1 man.Sv is of
the order of 10000 t (1,2). However, this calculation assumes all of the
steel to be at the level determined on the basis of the individual dose
criterion for clearance" 
(1) Application of Exemption Principles   to the Recycle and Reuse of
Materials  from Nuclear Facilities, IAEA Safety Series, 111 P-1.1, 1992
(2) Radiological Protection Criteria ffor the Recycling of Materials from
the Dismantling of Nuclear Installations, CEC, Radiation Protection 43, 1988

I wish you all a very nice merry Christmas and a good year in 1999

J.J. Rozental
josrozen@netmedia.net.il
Israel 

           



At 09:12 AM 12/22/98 -0600, you wrote:
>To the philosophical interest of Bill Lipton (and others):
>
>The de minimis principle is based on the requirement that the dose is so low, 
>that no measures for radiation protection are required - the trivial dose.
>Most authors proposing values of trivial individual dose have set the level 
>of annual risk of death which is held to be of no concern to the individual 
>at 1E-6 to 1E-7. Taking a rounded risk factor of 1E-2 per Sv for whole body 
>exposure as a broad average over age and sex, the level of trivial individual 
>effective dose equivalent would be in the range of 0.01 to 0.1mSv/a. 
>That means to me, if this dose is trivial, the risk will be the same. 
>Perhaps, the fatal error lies in the linear dose model. There is a threshold 
>we should consider - the trivial risk threshold.
>
>Merry Xmas!
>
>Joerg Feinhals
>feinhals@tuev-nord.de
>
>This opinion is not strictly mine, it is from safety series 89 of IAEA!
>
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