[ RadSafe ] Basis or Bases for Sealed Source Leak Test Detection Level

[Costigan, Steve]

I don't know where it comes from but I've learned from several events that it's a really bad idea to use that value to make any decisions about a leaking source. Small leaks have turned into big ones during routine handling between leak tests, with pretty bad consequences.  Because of those events, in several of the procedures that I've been responsible for I've required that a source with any detectable removable activity (not including radon/thoron progeny, of course) be stored and handled as a contaminated item. 

Regards,

Stephen (Steve) Costigan, CHP
Group Leader, Radiation Protection Programs, RP-PROG
Los Alamos National Laboratory 
(505) 665-9435
costigan at lanl.gov


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of roseb at gdls.com
Sent: Friday, June 17, 2016 12:38 PM
To: The International Radiation Protection (Health Physics) Mailing List <radsafe at agni.phys.iit.edu>
Subject: [ RadSafe ] Basis or Bases for Sealed Source Leak Test Detection Level

Does anyone subscribed to this list know off-hand what the basis is or bases are for the 185 becquerel (0.005 microcurie) detection level for sealed radioactive sources?  Does the level have a technology basis (e.g. 
level of detection capability for a measuring instrument) or a health basis (committed or effective dose due to exposure at the stated detection level)?

This leakage detection level appears to apply for most sealed sources whether used for brachytherapy, industrial radiography, or other industrial or research application that uses specifically licensed sources.  It also appears to apply regardless of radioisotope contained in the sealed source (exceptions include certain tritium devices and exempt quantity sources).

I am aware of ANSI N44.2-1973, leak-testing radioactive brachytherapy sources (I do not have a copy of this standard to see if it provides the basis or bases for the stated level).  I am not able to locate anything online that provides basis or bases for 185 becquerel (0.005 microcurie) being the seemingly universal lower limit of detection for leaking radioactive sealed sources.

Henry

Boyd H. Rose, CM, CIH, CHMM, EI
Sr. Safety and Environmental Engineering Specialist Corporate Radiation Safety Officer General Dynamics Land Systems
38500 Mound Road
Mail Zone 436-10-80
Sterling Heights , MI 48310-3200
Tel: 586 825 4503
Fax: 586-939-4140
E-mail: roseb at gdls.com

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