Yes we do use OSLD dose for our end of year total.
Fred Rosser GGNS RP Supervisor ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Friday, December 17, 2010 8:50 AM To: [email protected] Subject: Re: Powernet: Electronic Dosimeter Bias Hi June, The 7% bias is applied during the ED calibration. In other words, apply a 1.07 correction factor in the software. That may be increased depending on results from our most recent two outages. We use the Mirion calibrator IRD-2000; it contains a Cs-137 source and "transfer" dosimeters to standardize the calibration to NIST. And to answer later questions, we also round in a fashion similar to Duke's. We use the DMC-2000S EDs with an integer display, not tenths because we don't want workers to misread a value of 10.1 thinking they had 101 mrem (the decimal is hard to see). Hope that helps. Now I have the $64,000 question for you folks, particularly those who deliberately bias your EDs high to avoid having an estimated dose below the TLD (or OSLD) dose of record. When you do this, do you request INPO change your annual dose to the TLD dose to bring your totals back down and improve your performance relative to other plants? Thanks, Eric Eric M. Goldin, CHP Southern California Edison <[email protected]> From: [email protected] To: [email protected] Date: 12/15/2010 12:28 PM Subject: Re: Powernet: Electronic Dosimeter Bias Sent by: [email protected] ________________________________ Is this bias 7% the difference between TLD and EAD collective and individual dose after a read period? or is it the correction factor set on the calibrator compared to Cs-137 source? Do you irradiate on a phantom? or a box calibrator? or with a MG robot calibrator setup? How is your transfer cal performed? We have a over all bias factor after TLD reads of 7 to 8% with the EAD being high. To reach this we need to set the Cs-137 robot calibrator to 1.18 correction factor. This has been cross checked on a NVLAP phantom in open air geometry. I'd like to ensure we are comparing the same criteria. June L. Scott [email protected] Phone: 419-321-8555 Cell: 419-367-6651 Davis Besse Nuclear Power Station 5501 N State Route 2 Oak Harbor, Oh 43449 [email protected] om Sent by: To owner-power...@hp [email protected] s1.org cc Subject 12/15/2010 10:43 Re: Powernet: Electronic Dosimeter AM Bias Please respond to [email protected] Responses from San Onofre. We also use DMC-2000S electronic dosimeters. Regards, Eric 1. and 2. EDs are biased up 7% to more closely match TLD data. Not really over-responding. Really a correction for slight ED geometry and energy under-response compared to TLDs. 3. Not yet. We've had these EDs in service for about 5 years and only just recently implemented zinc injection. Will be completing another TLD/ED study after the current steam generator replacement outage. Eric M. Goldin, CHP Southern California Edison <[email protected]> From: "Courtenay, Christopher C" <[email protected]> To: "[email protected]" <[email protected]> Date: 12/14/2010 11:48 AM Subject: Powernet: Electronic Dosimeter Bias Sent by: [email protected] Duke Energy would like to know the following: 1. Do you bias your EDs to over-respond in the field? 2. What bias do you apply if you do? (5%, 10%, etc) 3. Have you noticed a change in ED response due to changing plant conditions (Co58/Co60 ratio changes due to Zinc injection, etc) or specific jobs (weld overlay, alloy 600, etc)? Point of reference – Duke uses the DMC2000S from Mirion. Chris Courtenay Engineer, Duke Energy 980-875-5005 "To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be." ----------------------------------------- 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.>‑wjǫ'‑axwO+"rĨr'0z^ih'*'>‑wj!jm &j)Zb(hziZ+^\0zl֊!.zb{ {Zr"nǥ!jǥ;( ,q( ----------------------------------- 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]
