Duke Energy Response: Do you use the DMC-2000S version 4? -Yes Do you use the DMC-2000S version 4 with previous DMC-2000S versions? -Yes Have you seen a difference in response between version 3.x and version 4 of the DMC-2000s? -Yes Do you use a different bias factor(s) for each version? -Yes Do you use a different bias factor(s) for different jobs?-No What bias factor(s) do you use for the version 3.x and the version 4?-V3-15%; V4-5% Since the introduction of the Version 4 (V4) DMC2000S EDs into the Duke Dosimetry program in late 2011, an increasing delta between TLD and ED values has been observed at all Duke sites except one. In all cases where the increase has been observed, the majority of their ED inventory is V4s (up to 95% V4s). Based on Mirion DMC2000 energy response data, the V4 ED clearly has different response characteristics as compared to the older V3 version. To further evaluate ED energy response differences, Duke had V3 and V4 EDs irradiated by an A2LA accredited Dosimetry Calibration lab. Results of these irradiations show about a 5% difference in the Cs-137 response for the V3 vs. V4 EDs and >20% difference in energy response for M250 x-rays. Anyone wishing further information please do not hesitate to contact me. Patrick J. LaFrate, CHP Manager - Duke Radiation Dosimetry & Records 980-875-3204 [email protected]
From: [email protected] [mailto:[email protected]] On Behalf Of Nadeau, Marc Sent: Friday, December 05, 2014 8:24 AM To: '[email protected]' Subject: Powernet: Benchmark - DMC-2000S version 4 vs. version 3.x *** Exercise caution. This is an EXTERNAL email. DO NOT open attachments or click links from unknown senders or unexpected email. *** Has anybody had to change their ED correction bias since adding the DMC-2000S version 4 to their electronic dosimeter population? If you use the DMC-2000S version 4 and also use / or have used version 3.x, can you answer the questions below? Thanks! Recently Seabrook place the DMC-2000S version 4 into service. This version introduced changes to the device angular and energy response, as compared to earlier versions (MIRION Customer Notification dated 12/2013). Since we started using the version 4, higher than expected ED dose readings have been seen for certain jobs, such as S/G Nozzle Dam work, Fuel Moves, and Rx Head Assembly/Disassembly. We believe it's from the higher angular and energy response, and would like to know how others have dealt with the change. Do you use the DMC-2000S version 4? Do you use the DMC-2000S version 4 with previous DMC-2000S versions? Have you seen a difference in response between version 3.x and version 4 of the DMC-2000s? Do you use a different bias factor(s) for each version? Do you use a different bias factor(s) for different jobs? What bias factor(s) do you use for the version 3.x and the version 4? Thanks again for your help, and I hope everyone has a good holiday season. Marc Marc Nadeau NextEra Energy Seabrook Radiation Protection Phone: 603-773-7815 Fax: (603)773-7303
