Re: Bacteria in Reactors -Reply

[Lonny Eckert <LLE@nrc.gov>]

While somewhat tangential to the existance of  bacteria in primary systems at
NPPs, some BWRs have microbes in their radwaste processing systems.  Some
licensees have gone to great extents to eliminate this nuisance.  There are several
industry guidance documents and at least two Information Notices which deal with
this subject...  The food source is often cellulose-based resins (powdex for
example).

For BWRs, the RWCU (reactor water cleanup) system draws from one of the
recirculation loops and the reactor vessel bottom head drain.  Temperature of the
coolant is dropped significantly to around 160 degrees fahrenheit by regenerative
and non-regenerative heat exchangers.  Coolant temperature and flow must be
dropped because the resins can't handle extreme conditions.  Spent RWCU resins
are sluiced to radwaste for processing.  RWCU is really still part of the RCS
(reactor coolant system) boundary, but it can be isolated from the rest of the RCS. 
Perhaps this is what the questioner was referring to?


Regards,
Lonny Eckert

-standard disclaimers apply-