[ RadSafe ] RE: Radiation Sources at the U.S. Capitol and Library of Congress Buildings

[Zack Clayton]

Ted asked:

     If a radiological event were to occur tomorrow in the US, what
would be the ruling cleanup criteria?  I'm interested in distinguishing
between ingestible/respirable contamination and direct "shine" from
ground and building surfaces.  I've heard 100 mrem/year, but that would
require tear-down and removal of the national capitol and other granite
structures.  Do the same numbers apply regardless of the natural
background at the event? 
     What document or standard would apply?  Are there certain state
regs that would override national regs if the state regs were more
severe?
     I'm looking for legal limits, not opinions or philosophy, for the
moment.  References appreciated.
Thanks.
Ted Rockwell
============= 

Ted,

I don't see any other answers yet so here is my 2 cents.

The Reg is EPA 400 "Manual of protection Action Guides and Protective
Actions for Nuclear Incidents."

The protective action is relocation for populations exposed to 2.0 REM
first year, 0.5 REM in any subsequent year, and 5.0 REM total over 50
years exposure including the first year and subsequent years.  Skin beta
dose is allowed to be 50 times this EDE.

The unstated assumption is that there would be no relocation for
contamination levels less than those stated, so the population would be
allowed to continue inhabiting the area.  An interpretation of this
would be a cleanup standard of 2.0 REM in the first year and 0.5 REM in
any subsequent year for a continuously exposed individual. 

I do not see any reference to "above background" and in fact, how many
locations have an official background reference that would be recognized
in court?

Now this is for an assumed power plant accident and release, and
assumes a fission byproduct mix in keeping with that, but it does not
prohibit use for other "incidents".

I'm sure there are other guidelines out there for specific situations,
but this is what I am used to working with for my specific planning
activity.

Levels to protect the food supply are considerably lower as that
involves internal exposure and the DRLs are derived for each isotope
individually.  These were also in the EPA manual but have been
superseded recently with FDA DRLs published by them.



Zack A. Clayton
Ohio EPA - DERR
email:  zack.clayton at epa.state.oh.us
voice:  614-644-3066
fax:       614-460-8249