Re: Badge Sensitivity Topic

[LIPTONW@dteenergy.com]

Two things: 
 
(1) In a situation like this, not only should you document an investigation, 
but you should discuss this with the employee and obtain his written 
concurrence that he understands why his assigned dose is being changed from 
that reported by the dosimetry processor. 
 
(2) Of all the possible reasons for an anomalous dose that you investigated, 
you didn't mention medical radiation, i.e., the possibility that the
employee 
received nuclear medicine diagnosis or therapy, or wore the badge while
being 
x-rayed.  Short-lived material, such as Tc-99m, would have been long gone by 
the time of your investigation.  There is also the possibility that the 
employee has a second job which involves radiation exposure, and that he
wore 
your badge for that.  
 
The opinions expressed are strictly mine. 
It's not about dose, it's about trust. 
 
Bill Lipton 
liptonw@dteenergy.com 
 
 
You wrote: 
 
>A comment was made yesterday about "arbitrarily lowering" doses.  I would
be  
>surprised if anyone is "arbitrarily" lowering doses.  However, evaluating
the  
>TLD processor's report of measured doses relative to a worker's expected
dose 
is  
>a legitimate act of dose evaluation.  A case in point is one I had to deal 
with  
>a few years ago.  At my plant, we only have uranium hexafluoride, a few 
button  
>sources for instrument checks and calibration, and some laboratory
standards. 
  
>One of our employees came up with a quarterly whole body dose of more than
9  
>rem.  I've forgotten what the skin dose was.  Review of the glow curves
left 
no  
>doubt the TLD had actually been exposed to something, but we have no
sources  
>onsite that could have caused this kind of dose in 3 months.  I think the
TL  
>chip readings inferred exposure to hard photons and low energy particles. 
I  
>tried every way I could think of to find something wrong with the TLD  
>processor's system.  No luck--they were doing everything right as far as I 
could  
>tell.  Based on this, we concluded the TLD (in this specific instance) did 
not  
>accurately report the person's occupational dose and I assigned dose to the
 
>person based on his coworkers' dose for the quarter.  In the end, I wrote a
 
>report describing the investigation and documenting my reasons for not 
assigning  
>the TLD processor's reported dose.  This has subsequently been reviewed by 
DoE  
>and the NRC and they concurred with my findings. 
 
>A few other relevant facts about this incident:  people took their TLDs
home  
>with them each day when this happened; the person's work location was not
in 
a  
>radiation area, a contamination area, or a radioactive materials area.  We 
also  
>surveyed the employee's house, houseboat, vehicles, etc.  Didn't find 
anything  
>radioactive.   

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