RE: Y-90

["James Dwyer" <JPD1@NRC.GOV>]

Chris:



I don't often defend regulators but in this case I believe the comment about Y-90 and shielding came from a product sales representative, not a regulator. 



Jim Dwyer

USNRC, Region 1



>>> "Marthaller, Chris" <Chris.Marthaller@wipp.ws> 02/13/02 09:15AM >>>

As an aside to the topic of the gamma that is or isn't associated with Y-90

as part of the RCT continuing training program at Hanford we actually

measured the distance that a Y-90 travels in air.  This was in the spring of

1997 if memory serves me.  From a 1.5 mCi Sr/Y-90 check source, using a

pancake GM probe w/scaler.  Using the Critical Level calculation.  We were

able to show that you could detect beta above Lc at distances of 18 - 20

feet depending upon the density of the air that day. It was an eye opener

for the technicians as they were required to calculate the travel distance

based on Emax then SWAG for the true distance.  The vast majority were

several feet short of the actual travel distance.  So for a regulator to say

you don't need to worry about beta shielding means that regulator should do

some soul searching.



Chris A. Marthaller, RRPT

Sr. Training Coordinator, WIPP

(505) 234-8661

Chris.Marthaller@wipp.ws 

I alone am to blame for my statements.

"If we keep doing what we are doing, we will keep getting what we are

getting." ANON





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