At FCS we evaluate OSLN/DRD data is the following manner:
* In addition to the INPO criteria, we compare individual OSLN/DRD data to a more stringent criteria of (SRD range) = (OSLN) +/- 2.5*sqrt(OSLN). This criteria came from Mike Lantz. * We use a +/- 15% criteria for the aggregate OSLN/DRD data. We shoot for within +/- 5% -- which we have been of late. We use this as an indicator of the overall health of the program. Our main reason for this criteria is to make it easier to plan & track radiological work and maintain worker confidence in the accuracy of our dosimetry program. I should mention that analysis of our OSLN & DRD data has identified a few distinct plant conditions, evolutions, and areas that have sufficiently different average gamma energies from the overall plant average (e.g., inside the bio shield at power, in containment the first couple weeks of an outage, radiological waste operations, ect.). We are often able to track excessive OSLN/DRD mismatches to this type of area/condition where most of an individual's dose is over a short period and/or single RWP. We calibrate the DRDs to the plant average gamma energy, so when a worker is in one of these areas/conditions, the OSLN/DRD mismatch for that individual can and is more than our aggregate mismatch. Since we have no good way of adjusting the DRD bias on a RWP/task-specific basis, we satisfy ourselves with explaining this type of OSLN/DRD mismatch as based on a different gamma energy from the plant average. Of course, we make sure there is not another reason before going down that road. 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 Huneycutt, Scott Sent: Sunday, November 27, 2011 1:39 PM To: '[email protected]' Cc: Huneycutt, Scott Subject: Powernet: period TLD-ED dose discrepancy criteria There are recommendations and criteria for performing investigations when an individual's TLD or DRD period results are greater than 100 mrem and differ by more than 25%. Does your site have an acceptance criteria for total period dose for the site? What difference between total site TLD and Estimated dose is considered unacceptable? If so, what is the basis for your criteria? Thank you, Scott Huneycutt Xcel Energy | Responsible By Nature Senior Health Physicist Monticello Nuclear Generating Plant 2807 West County Road 75, Monticello, MN 55362 P: 763.295.1380 F: 763.295.1225 E: [email protected]<mailto:[email protected]> ________________________________________________ XCELENERGY.COM<http://www.xcelenergy.com/> Please consider the environment before printing this email ---------------------------------------------------------------------- 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.
