Vermont Yankee: 1. Yes 2. +7% for Siemens EDs 3. We changed from TLD to OSLD about the same time that we did power uprage and zinc injection so its difficult to determine what caused the shift. We were running 7 to 10% on average for a quarter vs TLD but are now 2 to 6% vs OSLD. We have always had a scattered and thus lower average energy environment except for steam affected areas and set the original bias based on side by side exposures in the plant environment rather than using a single source. I suspect the shift is due to change over to OSLD. I'm tracking vendor QC's in addition to our own QC shots and have seen some variations due to the vendor processing.
John Geyster RP Support Supv Entergy Vermont Yankee (802) 258-5471 ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Courtenay, Christopher C Sent: Tuesday, December 14, 2010 2:37 PM To: [email protected] Subject: Powernet: Electronic Dosimeter Bias 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."
