Re: Asking for opinions

[Neon John <johngd@bellsouth.net>]

"Archer, Joe" wrote:
> 
> A situation came up at our facility and I am interested in getting a general
> consensus as to how to interpret the issue.
> 
> We had a TLD rack at the entrance to our facility where people put their
> TLDs when they leave the site. This rack is a vertical board between 3 & 6
> feet above the floor. 3 feet in front of the rack is a wall. The wall is 16
> inch thick concrete from the floor to about a height of 3 feet and glass
> from 3 to 7 feet above the floor. If you are standing at the TLD rack
> looking out, your 135 degree field of view would be obstructed by two
> concrete door jams about a foot wide each and the rest would be glass.
> 
> A concern was raised that radioactive material would be routinely parked
> about 10-15 feet outside the glass and that this might dose the TLDs
> unnecessarily. Two independent assessments by Rad engineers (one a CHP)
> concluded that between 20-40 mrem per quarter may be absorbed by the TLDs
> and that moving the rack was a reasonable precaution. This actually has some
> relevance considering the collective dose goals of the site.
> 
> A management type CHP wrote up an analysis that assumed that the mostly
> glass wall was approximated by a 16 inch thick concrete wall and he
> concluded that the TLDs would get no dose. The question I would like
> RADSAFERs to comment on is "How would you interpret a case where an HP
> approximates a mostly glass wall as a concrete wall for shielding
> calculations?". 

Seems to me like this management type is trying to politely tell
everyone to drop it, that it's not worth the cost or effort to sweat
it over 20-40 mrem/qtr, especially when proper control badging of
the badge station will completely address the issue.  You are using
control badging, aren't you?  Since you didn't tell us the thickness
or composition of the glass nor the composition of the concrete
wall, I can't comment on the approximation.  One inch thick
bullet-proof glass vs a concrete block wall might not be too far
off.

>Although there is no human health issue involved, would this
> border on being or is it blantantly unethical?.  Obviously, reasonable
> people can disagree but for the purposes of this discussion, give your
> opinion based on the assumption that you could see the radioactive material
> from the TLD location and 100 or at least 99 out of 100 people would agree
> that the only thing directly between the source and the TLDs was a pane of
> glass.

Please don't take this personally but as a taxpayer, I have to
question the ethics of involving at least 3 professionals and the
associated cost, and probably several meetings, for what is
essentially a bookkeeping matter.  hanging control badges on the
stations is standard practice and completely resolves the question. 
Use a badge on every corner of the station if you think there is a
field gradient across the station.  I know that in the big picture
of the government spending half a trillion dollars every year, this
isn't much of a cost item but every little bit adds up.  BTW, when
the calculating was done, was dose from the concrete computed?  If
that concrete used flyash for filler or even some sorts of sand, it
could be "hot", at least in the context of that dose level.
> 
> Thank you to all who chime in.
> Joe Archer

That was my ding-dong :-)

-- 
John De Armond
johngdSPAMNOT@bellsouth.net
RDS Inc.
Cleveland, TN


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