RE: High Contamination

["Lieskovsky, Miro" <MLieskovsky@nbpower.com>]

Radsafers:

Please reply to the list as this may be of interest to others. 

Mike, 
could you please provide information on isotopic constituents found?  I
wonder if activation or fission product prevail.  The dose rates and the
beta/gamma ratio seem to be extremely high.  However, deposition of
contaminants in systems with low flows (I presume your sensing line has)
is generaly higher.     

Thank you in advance.

Miroslav Lieskovský,
Health Physicist,
Point Lepreau G.S., NB POWER
***********************************************************************
bus.: 	(506) 659 7421	mlieskovsky@nbpower.com
res.: 	(506) 636 7629	miroslav@nbnet.nb.ca
***********************************************************************
P.S.: ...a clueless lobotomized nuke! Yep,is there any better
combination? 8^)



>-----Original Message-----
>From:	Mitchell, Michael T. [SMTP:mtmitchell@tva.gov]
>Sent:	Tuesday, May 05, 1998 11:24
>To:	Multiple recipients of list
>Subject:	High Contamination
>
>Hello All,
>
>We just completed a short mid-cycle outage here on one of our units.  We
>had been operating for some time with some known leakers.  Following a
>scram which ended a 390 consecutive day run it was decided to
>dissassemble and replace the leakers.  Naturally this presented an
>opportunity to make an entry into primary containment (drywell for us
>BWRs) to find and repair an unidentified leak.  This is where our
>problem arises.  The leak was on a reactor water recirculation system
>sensing line.  Thanks to our less than stellar fuel performance
>contamination levels in the drywell were staggering.  Levels in the
>immediate area of the leak were as high as 260 rad/hr beta and 6 rem/hr
>gamma.  General smearable levels were from 3 to 25 million dpm/100cm2.
>Needless to say, it presented quite a challange in the area of
>contamination control and personnel protection.  Now to the problem:  We
>have a scheduled outage in Oct 98 on this unit.  Based on the assumption
>that we have rectified the fuel problem,looking at the isotopic mix, and
>considering half-lives, I still think we will have at least half of the
>goodies around in Oct.  We have formed a team to investigate decon
>options come Oct.
>
>I would greatly appreciate hearing from any of you who may have had
>experience cleaning up such levels, and any successful/suggested
>techniques.  Of course, only limited time will be allowed in the
>schedule.  Such are the challenges for the nuclear plant HP.  Thanks in
>advance. You can respond to me directly. 
>Mike Mitchell
>
>=======================================================
>Michael. T. Mitchell
>Health Physicist
>
>Tennessee Valley Authority
>Browns Ferry Nuclear Plant
>Phone: (205) 729-2401
>Fax: (205) 729-3157
>mailto:mtmitchell@tva.gov
>