Humboldt Bay responds with the following: All of our alpha ratios are less than 50 to 1. So we have frisking requirements for all of our areas
Ludlum 2350-1 Data Logger with 43-90 The 43-90 is a ZnS(Ag) scintillation detector with an area of 125 cm2 and an average efficiency for Pu239 of ~20% May also be used with Ludlum 43-68 Gas Flow Proportional Detector with an area of 126 cm2 and an average efficiency for Pu239 of ~20% Ludlum Model 3 with scaler option (the scaler option provides a digital readout in addition to the analog with count times of 0.1, 0.2, 1, 2, and 10 minutes) is used with the Model 43-1. The 43-1 is a ZnS(Ag) scintillation detector with an area of 83 cm2 and an average efficiency for Pu239 of ~33% Frisking is done at the Step off pad by an RP technician. We use a scaler and hold the instrument steady for two minutes. Normal movement of a frisker can't be done looking for alpha contamination. We also use a self absorption factor of two for each instrument. And you can't detect at 20 dpm/100cm2 on a person. The levels that can be resonably detected are about a factor of 5 above that. John Albers Radiation Protection Manager -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Friday, August 26, 2011 10:43 AM To: [email protected] Subject: Powernet: Alpha Frisking Davis Besse requests the following information: What type of instrument(s) are being used to alpha frisk (as recommended by EPRI) in Level III alpha areas with <50:1 ratio? Is the worker frisked immediately at the area? Or at the containment exit or other area? Does the worker self-frisk, or does a technician frisk them? Thank you for your response! Claudia L. Sacha RP Services Supervisor (Acting) [email protected] Phone: 419-321-7303 Davis Besse Nuclear Power Station ----------------------------------------- The information contained in this message is intended only for the personal and confidential use of the recipient(s) named above. If the reader of this message is not the intended recipient or an agent responsible for delivering it to the intended recipient, you are hereby notified that you have received this document in error and that any review, dissemination, distribution, or copying of this message is strictly prohibited. If you have received this communication in error, please notify us immediately, and delete the original message. ----------------------------------- Powernet - a service of the Health Physics Society Power Reactor Section Powernet archives at http://www.mail-archive.com/[email protected]/ Reply to: [email protected] If Questions, contact Mike Russell, CHP at [email protected] ----------------------------------- Powernet - a service of the Health Physics Society Power Reactor Section Powernet archives at http://www.mail-archive.com/[email protected]/ Reply to: [email protected] If Questions, contact Mike Russell, CHP at [email protected]
