Re[2]: Measurement of Neutron Exposure In NPP?

["TED S. BOHN" <BST@inel.gov>]

      Radiological Engineering (bst@inel.gov)
      6-1279  MS 4138  FAX 6-8959  Pager 5841
Has anyone ever made use of Bubble Dosimeters.  We've used then to determine
particularly low level neutrons that the Rem Ball instruments wouldn't pick
up.  We've used them with great success to determine the FNCFs (Facility
Neutron Correction Factors) in laboratories.  It does get tiresome counting
bubbles however; but they do work well for special circunstances.

*** Reply to note of 06/05/96 11:56
To: RADSAFE --INELMAIL RADSAFE

Subject: Re[2]: Measurement of Neutron Exposure In NPP?
     Bob Flood gave a very good overview of the question. I will only add
     that we did an energy spectra analysis in each of our four reactors.
     Two are Westinghouse and the other two are Combustion Engineering. We
     utilized two methods to determine the energy at several points within
     the reactor buildings, the fist was the Bonner Spheres and the other
     was a Tissue Equivalent Proportional Counter (TEPC). Battelle Pacific
     Northwest laboratories was provided a contract to perform this
     evaluation for us (back in early 1983 I believe). The TEPC was more
     reliable and provided excellent output documentation.

     Since several energies were identified we used the most conservative
     correction factor for our TLDs, also the Panasonic UD802-AT. It is
     essentially based on the Cf-252 moderated D2O.

     We have not performed another spectra analysis but would if there were
     a major structural change which would potentially change the spectra
     to which our workers were exposed. We do neutron surveys and TLD
     surveys for work evolution changes in areas where data has not been
     collected before.


     Sandy Perle
     Supervisor Health Physics
     Florida Power and Light Company
     Nuclear Division

     (407) 694-4219 Office
     (407) 694-3706 Fax

     sandy_perle@email.fpl.com

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