FCS Response below. We switched to the OSLN & DMC-2000S in 2011. * Do you use TLDs or OSLDs? OSLN * What type of ED do you use? DMC-2000S electronic dosimeter * Do you bias your EDs high? If so, how much? +10% We expect to tweak/refine this over time. The initial bias was determined from some test exposures of the DMC-2000S and OSLN on a phantom. * How long are your monitoring periods? 6-months on line, breaker-to-breaker for outage * What are your typical TLD/OSLD vs. ED results during a normal period? During an outage? Overall, within 5%. There are outliers depending on the average gamma energy where the worker got their dose as well as due to the normal (and expected) variations between individual OSLNs and DMC-2000S EDs. We set the ED bias based on the overall plant average gamma energy. We have identified a few distinct periods/locations that differ enough from the overall average to have a noticeable effect of the OSLN/ED matchup. Examples include: the first week or so inside the bio shield during outage, radiological waste operations aged materials), and inside the bio shield online. * Are your results consistent? Yes * Do you use a vendor for processing or is it done in-house? Landauer processes our dosimeters. We did buy the InLight reader for refining a field estimate if/when needed. * Which vendor do you use? Landauer Just a note, we also are using a 5 mrem threshold for the OSLN. Combined with the 6-month monitoring period, we have identified some dosimeter storage locations (we do not allow staff to take them home) that have slightly different background levels. The differences were not enough to show up with our old 8 mrem threshold and 3-month wear period. We verified the differences using long exposure time (~24-hr) measurements with an integrating micro-R meter.
David Brehm Fort Calhoun Nuclear Station Supervisor - Radiological Equipment & Dosimetry Office: 402.533.7582 Cellular: 402.214.0107 Pager: 402.561.3310 From: [email protected] [mailto:[email protected]] On Behalf Of Amber Cassell Sent: Thursday, January 26, 2012 1:47 PM To: [email protected] Subject: Powernet: TLD/OSLD vs. ED Dose Dresden has recently switched over from TLDs to OSLDs. We would like to get an idea of what to expect regarding OSLD vs. ED results. We would also like to compare our TLD vs. ED results with others in the industry. I would like to pose the following questions: * Do you use TLDs or OSLDs? * What type of ED do you use? * Do you bias your EDs high? If so, how much? * How long are your monitoring periods? * What are your typical TLD/OSLD vs. ED results during a normal period? During an outage? * Are your results consistent? * Do you use a vendor for processing or is it done in-house? * Which vendor do you use? Would anyone be willing to share data for the % difference in TLD/OSLD vs. ED from last 2 years? Amber Cassell, MHP Dosimetry Specialist Dresden Station 815-416-2417 [email protected]<mailto:[email protected]> ---------------------------------------------------------------------- This e-mail contains Omaha Public Power District's confidential and proprietary information and is for use only by the intended recipient. Unless explicitly stated otherwise, this e-mail is not a contract offer, amendment, or acceptance. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.
