Re: Off-site dose for SAR

["Sorensen, Scott" <ssorensen@doeal.gov>]

Radsafers and John Poston:

>If you were preparing an off-site dose calculation for a DOE nuclear
facility:

>1) Would you calculate the CEDE, only? Why?
>3) What dose limit would you compare your result to? Why?
>4) Would you calculate the organ doses and the CEDE? Why?
>6) What dose limits would you compare your results to? Why?

DOE Order 6430.1A "General Design Criteria" requires that radiological
siting criteria are required to be calculated in terms of CEDE
(0200-1.2).  DOE Order 6430.1A also has organ-specific limits.  As such,
CDE estimates would also need to be evaluated (0200-1.3).  

DOE 6430.1A appears to be still in effect at this date.  Note that these
are guidelines, not absolutes (in theory!).  You should also explore
making particle-size adjustments.  Once again, this should be acceptable
(in theory!).

>2) What CEDE dose conversion factors would you use? Why?
>5) What dose conversion factors would you use? Why?

10 CFR 835.2 references the use of Federal Guidance Report No. 11 (EPA
520/1-88-020) in its definitions of ALI and DAC.  I would look here
first.  DOE also provides another source for DCF in "Internal Dose
Conversion Factors for Calculation of Dose to the Public (DOE/EH-0071,
1988)."

A return question for Radsafers: Does it make sense to calculate nuclear
facility siting criteria in terms of CEDE?  

Nuclear facility safety criteria appear to based on the prevention of
observable deterministic effects from an accident.  The US AEC "Medical
Aspects of Radiation Accidents, 1963" suggests that the minimum dose
considered to be harmful is 25 rads.  IAEA Safety Series No. 21 "Risk
Evaluation for Protection of the Public in Radiation Accidents, 1967"
proposes a safety evaluation criteria of 25 rem to the whole body.  10
CFR 100 provides an exclusion area threshold of 25 rem whole body dose
from fission products.  

The "rub" is applying these criteria to radionuclides which deliver
chronic, organ-specific dose (e.g., uranium fuels, transuranics).  In
this case, 25 rem CEDE criteria appears excessively stringent (leading
to costly mitigative measures).  On a health perspective, the public may
be adequately protected (i.e., no observable deterministic effects) at
actinide exposures corresponding to 100 rem CEDE (or greater).  Yes, the
politics of such a threshold would certainly be delicate, to say the
least...  :-)

This issue may also apply to the NRC world in the near future.  The
430th Advisory Committee on Reactor Safeguards (April, 1996) proposed
modifying 10 CFR 100 to involve calculation of dose in terms of TEDE...

Regards,
Scott A. Sorensen
ssorensen@doeal.gov