RE: Ni-63

[JReed <jreed@utk.edu>]

Source degradation (i.e., leakage) is also accelerated by: 1)  unregulated temperature (noted problem for early units); 2) use of HOT liquids to clean the unit.

Craig Reed
Bechtel Jacobs Co LLC
Legacy Waste Project - Lead HP
Oak Ridge, TN
Jreed@utk.edu
E77@ornl.gov
 

-----Original Message-----
From:	Richard J Sobilo [SMTP:rjsobilo@beckman.com]
Sent:	Thursday, June 25, 1998 11:18 PM
To:	Multiple recipients of list
Subject:	Re: Ni-63

Rafi:

I've done a huge number of wipe tests on these types of ECDs and have found
about10-15% of them with removable contamination, sometimes with much
larger levels than you've found. After a while you come to expect some
contamination since these devices are heated and take some chemical abuse
from the analyte. I wouldn't worry too much about what your finding there
(~300-400 cpm). At this level they are still not considered 'leaking
sources' and with an efficiency of probably approaching 80% for your LSC
you are below 1000 dpm/wipe (an generally accepted contamination level for
unrestricted release).

Rich Sobilo
rjsobilo@beckman.com