Re: Radiation litigation and Judges Opinions

["Samuel M. Stilwell" <sstilwel@PROTOPOWER.COM>]

Sandy, have heart.

Radiation monitoring at nuclear plants is very extensive during 
normal operation, and monitoring and surveys are greatly increased 
(at great expense) during refueling and maintenance evolutions. I, 
also, find it difficult to understand how someone can definitively 
state that "deliberate" actions were taken by SCE to, perhaps, 
minimize the ALARA "hit" on plant workers.

In 20 years in the nuclear industry, working primarily with 
instrumentation, I have found that, if anything, permanently 
installed field RMS area monitors (not portable units) tend to OVER-
indicate slightly. Factory calibrations are pretty accurate, but use 
of transfer calibrations typically requires the addition of small 
"fudge" factors based on specific installation geometries and to 
ensure compliance with plant Technical Specification limits. I have 
seen only a few rare cases, all due to component failures, where 
the indicated dose rates were grossly under-indicated. In each 
case, failure was easily noticed due to periodic check source and 
channel checks and the problem was fixed. In addition, rad monitor 
channel alarm setpoints tend to be WAY over any realistic 
personnel dose limits due to the equipment uncertainties that must 
be assumed when setpoint calculations are performed; channel 
uncertainties of up to 30% are often required when determining a 
setpoint (use of a log scale doesn't help, either). Personnel at 
nuclear plants also, of course, wear one or more TLDs and/or 
pocket/digital dosimeters at all times which provide further 
confirmation of any doses received. 

I have NEVER been in a situation where plant personnel 
deliberately allowed rad instrumentation to become or remain 
"undercalibrated". Channel failures typically result in immediate 
remedial actions, including additional, alternate monitoring 
methods, including more frequent manual surveys, until the monitor 
is fixed. Poor calibration can occur, but area monitors are not used 
alone; the pocket/digital dosimeters and TLDs would also have to 
be wrong (or misread) for total worker dose to be grossly 
underestimated. And I never forget that personal responsibility, 
common sense, and actually reading the RWP are the #1 aids in 
minimizing my dose during a job.

 
    
-------------------------------
Sam Stilwell
Project Engineer
Proto-Power Corporation
15 Thames Street
Groton, CT 06340
860-405-7208, ext. 3037
FAX 860-446-3096
Pager: 860-820-8495
sstilwel@protopower.com
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