RE: Contamination from Air Flow in Drain Systems

["Wiles, Jonathan C" <JCWiles@mail.bhi-erc.com>]

Billy,

Many years ago the Trojan Nuclear Plant had a similar problem when
differential pressure between Auxiliary Building floors would pull hot
particles out of the drains causing floor contamination.  In most drains we
were able to minimize the problem by installing rice paper, like the type
used for TIG welding, below the drain cover.  The rice paper readily
dissolves when wetted, and therefore the plant design basis is not
compromised.  Of course this only works in floor drains not normally
receiving water.

John Wiles

> -----Original Message-----
> From:	William E. Cox [SMTP:COXWX@naesco.com]
> Sent:	Tuesday, June 20, 2000 5:15 AM
> To:	Multiple recipients of list
> Subject:	Re: Contamination from Air Flow in Drain Systems
> 
> 
> 
> We have had some success controlling noble gas movement in the floor drain
> system with a retrofit trap device that fits into the floor drains called
> a
> "Dranjer".  I'm not sure of the manufacturer but they are available at
> http://members.nova.org/~dsaum/index.htm These are commonly used in radon
> mitigation applications for basement floor drains connected to drywells.
> Similar to your loop seals, you have to keep them filled with water on
> some type
> of routine basis.  A word of caution, they may restrict drain flow
> somewhat and
> should be evaluated against any design basis for operability issues.
> 
> Billy Cox
> Seabrook Station
> Health Physics
> (603) 773-7319
> coxwx@naesco.com
> 
> 
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