Sr-90

[David_B_Dave_Ottley@rl.gov]

     I am interested in the surface contamination release limits used for 
     Sr-90 in mixed fission product (MFP).
     
     NRC Reg Guide 1.86 gives a lower release limit for Sr-90 then other 
     beta-gamma emitters.  The DOE Rad Con Manual says that the higher 
     criteria may be used when the Sr-90 is contained in MFP.  DOE 5400.5 
     and 10 CFR 835 both indicate that the lower limit must be used when 
     the Sr-90 is enriched.
     
     No guidance is given on how much MFP must be present to be able to use 
     the higher limit or on what is enriched.  I believe enriched only 
     applies to isotopic enrichment i.e. Sr-90 ratio to other strontium 
     isotopes such as Sr-89 but many people believe it applies to an 
     increase in concentration.  Their logic is that the intent of the 
     lower limit is for when you have a lot of Sr-90 in relation to other 
     MFP.
     
     I am interested in knowing what other facilities have used as their 
     technical basis on this.  How much Sr-90 to MFP do you allow and still 
     use the higher limit?  What is your definition of enriched Sr-90?
     
     My phone number is (509) 376-8124 and
     my e:mail is David_B_Dave_Ottley@Rl.Gov
     Merry Christmas and a Standard Disclaimer