Re: RADSAFE digest 35

["Patrick D. Beyer" <pbeyer@post.its.mcw.edu>]

On Fri, 29 Oct 1993, Hector Mandel wrote:

> Date: Fri, 29 Oct 93 12:43:07 -0500
> From: Hector Mandel <mandel@romulus.ehs.uiuc.edu>
> To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject: Re: RADSAFE digest 35
> 
> 	With the advent of the new Part 20, our disposal options for
> 	animal carcasses containing radioactive microspheres has 
> 
> 	become extremely limited. To this end, we would like any 
> 
> 	information on conversion to non radioactive microsphere
> 	methods. The investigators normally use 3-4 different 
> 
> 	microspheres (Ce141,Cr51,Ru103,Nb95).
> 
> What's the problem?  Most of the isotopes used in microspheres are  
> short lived so the ash can be held for decay.  How does the new  
> 10CFR20 affect your disposal of microspheres?

Let me be more pacific ----


	1) Our license is written such that the effluent is calaulated
           with 100% of the activities being released as effluent. We are
           currently working on the study to determine the % effluent from
           microspheres. Even so the only pubished studies i have found 
           indicate that from 7 to 20 % stays in the ash depending on the
	   nuclide. ("Rtention and Subsequent release of Radioactivity
	   from the  Incineration of wastes Containing Microspheres"
           Health Physics,Vol. 59 No. 6)
 
	2) Incinerator Effluents (Air Effluent Concentraions in micro-Curies
	   per ml) have become more restrictive -

                           Old            New
		Ce141     2 EE-8	8 EE-10
		Nb95	  2 EE-8	2 EE-9
		Ru103	  2 EE-8	9 EE-10
		Cr51	  4 EE-7	3 EE-8	
		
	  With our current stack air flow we use approximatly 50% of our annual
          effluent with the existing Part 20 values. New part 20 values
	  raise this to over 1200 % for the year. We are also
	  recalculating the stack air flow but preliminary fiqures 
          show only a doubling of volume.

So basically its not the ash that is the problem it is the effluent
restrictions. We are looking at having to decay over 200 40lb dogs for
about six months if things stay as they are. This would call for a $20,000
investment for a freezer large enough.... Hench our dilemma