RE: Permanent Shielding -Reply

[Cliff Gray <cgray@postoffice.ptd.net>]

Lonny,

	Thank you for your response.  We are looking to shield the Recirc suction and discharge piping in our drywell using lead encapsulated steel panels that hang from chains from various existing supports.  The panels would stay a minimum of 3 inches away from the piping for heat expansion.  A company came to Limerick during our current outage to take pictures and measurements.  They say the shielding has been analyzed for seismic restraints and Jet Impingement scenarios, but they do not have any commercial applications in a dry well yet.     
This application will obviously save a lot of time, exposure, and money during refueling outages.  I will update the list if we are successful in our implementation.  

			Thanks again
			Cliff Gray
			cgray@postoffice.ptd.net
			Radiological Engineer, Limerick Generating Station

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From:  Lonny Eckert[SMTP:LLE@nrc.gov]
Sent:  Tuesday, February 27, 1996 7:44 AM
To:  Multiple recipients of list
Subject:  Permanent Shielding  -Reply

Cliff,

I have never seen "permanent" shielding in a
drywell anywhere and I doubt that your
engineering staff would permit such an
installation on other than a very limited basis.  It
might impact the ability of your containment
spray system to carry out its intended function. 
Don't forget fire protection if for some reason
you wish to use wooden planking rather than
metal planking.  Of course, it must be
seismically qualified if it is a permanent
installation.

Oyster Creek has installed permanent
scaffolding in their drywell.  This has permitted
them to quickly install their shielding in the
beginning of their outages.  FYI:  they have
placed an average of about 80K-100K pounds
of lead blankets in their small drywell the past
several outages.  Oyster Creek has some
unique considerations in that they have but one
hatch into their drywell while I imagine that you
have three.  This forces them to prestage the
shielding packages and to schedule their
shielding crews.  I think they would be your best
bet as a contact in Region I and are within
driving distance from LGS.  Good luck.


Lonny Eckert
NRC Region I
LLE@NRC.GOV