Re[2]: ALARA or Not? -Reply

[BRZGV@ccmail.ceco.com]

     Things to consider from a power plant perspective.
     
     Engineering controls such as HEPA units to filter air or spray bottles 
     to keep surfaces wet, etc. should be considered before respiratory 
     protection.  The dose required to set up engineering controls should 
     be considered into the respirator decision.
     
     During steam generator maintenance, workers are required to enter the 
     steam generator itself for periods of approximately 1 minute or less.  
     Typical dose rates would be 8000-12000 mrem/hr with many mrem/hr beta 
     of surface contamination.  Air samples for the areas inside the steam 
     generator most often come back 0.3 DAC or less; however, when the 
     workers enter the steam generator and perform work their motions cause 
     loose surface contamination to become suspended in air and cause 
     momentary airborne conditions.  It would not be uncommon for a steam 
     generator worker to enter a steam generator with an air sample less 
     than 0.3 DAC and come out with an intake of about 130 nCi of Co-58 and 
     30 nCi of Co60.  Even though the pre-job air sample may seem okay, I 
     would never argue with anyone who wished to use a respirator by 
     default due to the inability to accurately assess the conditions.
     
     When a worker does not wear a respirator for such jobs, they will most 
     likely need a facial decon or shower due to external contamination as 
     a minimum.  It is also very likely that they will be taking a trip to 
     the whole-body counter as well.
     
     I would suggest that if the dose for the job with and without the 
     respirator is equal, then use the respirator.  The process of 
     showering, whole-body counting the person, follow-up counts of the 
     person, lost work time by the craft person and RP personnel, etc. can 
     quite substantial.
     
     If the worker's body, now including the face with the respirator is 
     covered, then it is entirely reasonble to have a steam generator 
     worker enter the steam generator and come out without a count of 
     internal or external contamination.  This is the measure of a good 
     performance.
     
     If my calculation showed that the worker would take less overall dose 
     by not wearing a respirator and I could accurately assess the 
     conditions, then I would feel personally bound to have the worker 
     perform the activity without a respirator.
     
     Battery powered faceshields are now being used as engineering controls 
     instead of respirators.  These faceshields blow filtered air from the 
     top on the inside and there is an exhalation hole at the bottom.  The 
     faceshield also has rubber sides which cover the rest of the worker's 
     face.  These units appear to be effective.
     
     This is a peek into one perspective based upon a unique kind of work.  
     At power plants we typically have high external radiation fields and 
     radionuclides with higher ALI's, which means we rarely use respirators 
     any more.  We have a nice glove bag maker but can't justify the use of 
     a glove bag for contamination/airborne control due to the dose 
     required to set the thing up.  Other types of facilities which might 
     have lower external radiation fields and radionuclides with lower 
     ALI's (alpha emitters, DOE, etc.) might find themselves considering 
     respirators far more often than those in the power plant community.
     
     Feel free to share your opinions...
     
     
     Sincerely,
     Glen


______________________________ Reply Separator _________________________________
Subject: Re: ALARA or Not? -Reply
Author:  radsafe@romulus.ehs.uiuc.edu at INTERNET
Date:    4/30/97 6:19 PM


At 04:40 PM 4/30/97 -0500, you wrote:
>Overall risk assessments are *not* allowed?   Please review the Health 
>Physics position papers.  I believe there are specific positions in regards 
>to this matter.   Unfortunately I do not have mine handy with me and
>won't be back in the office for a couple of weeks. 
>
I've been out of nuclear power and in the DOE world for a few years now. My 
last experience in the NRC-regulated world was that factoring in IH issues 
such as the potential for heat stress, falling, and such was prohibited. 
However, if that is different now, I am pleased. But aren't such 
evaluations awfully difficult to justify/defend, especially if the worker 
doesn't want to give up the respirator?
     
     
Bob Flood
Stanford Linear Accelerator Center
(415) 926-3793     bflood@slac.stanford.edu
Unless otherwise noted, all opinions are mine alone.