Monticello Response below: 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 From: [email protected] [mailto:[email protected]] On Behalf Of Benjy P Bertossi Sent: Tuesday, July 16, 2013 5:53 AM To: [email protected] Cc: James P Stewart Subject: Powernet: DLR / TLD practices
Fermi 2 will be installing hand geometry this year and will allow security keycards to go home. We currently store our DLRs on security key cards and would appreciate your input on the below questions: 1) What type of DLR (TLD, OSL, Film) do you use? Mirion/GDS 760 TLD (Harshaw design) 2) Does your site take DLRs home? Yes, but we keep onsite the DLRs for infrequent workers (NRC, corporate, ect.) 3) If no, how/where do you store them on site? We store DLRs in the security building for workers that normally work offsite and are not expected to be available to exchange their DLRs. This rack has its own set of background controls. 4) If yes, do you use control dosimetry from on-site, off-site, or both to subtract background radiation? For our general population of workers, we store background controls in our training facility about one mile from the plant. Studies have shown these to be statistically the same as a set of TLDs taken home by a group of workers. Controls for DLRs stored onsite are stored in the same rack as those DLRs. 5) How do you do DLR exchange and how long does it take you? Quarterly, with some variation due to outages. Like others have stated, it takes about a week to get 90% of the DLRs. It takes a couple more weeks to get another 9%. The remaining 1% can take several more weeks or months and might not ever come back. For our last exchange, we had 42 stragglers after 2 weeks. We communicate to the site the last day DLRs can be exchanged (allowing 5 to 10 work days), and lock those workers that have not exchanged their DLR out of the PA until their supervisor meets with RP; that seems to help with promptness. 6) Any other pros/cons of taking DLRs home vs staying on site? Cons: Like others have stated, it takes more work for the exchange and tracking down stragglers. There is more variation in background subtraction so the LLD is higher and increases chances of false positives. Taking home TLDs should only be done in locations where the distribution of background dose rates has low variability. In areas with significant regional changes in background, you should consider keeping the DLRs stored onsite. We also have problems with workers taking them to other sites or on airplanes. Pros: aids EP response and allows the DLR to be more securely attached to the lanyard. Please respond to Powernet or Jim Stewart directly, [email protected]<mailto:[email protected]> (734.586.1388) Thanks, Benjy Benjy Bertossi Fermi2 - RP Supervisor 734-586-4935 [email protected]<mailto:[email protected]>
