Follow up: Radiation releases during TMI event on November 21 2009

Eric, We do not share copies of Condition Reports or issue reports with the public. On occasion, the NRC reviews these reports at the plants but we do not typically submit them to the agency. However, the answers to your other questions are provided in blue after each question. We have some follow up questions based on your press release of December 18, 2009. If the TMI containment was open for the steam generator replacement, we are trying to determine if cobalt was released and detected by Exelon’s monitors off the Island to the southeast. We know Cobalt 60 is an activation product - not a fission product - so it does not indicate a fuel failure. Nevertheless, the release(s) did come from inside the reactor. 1) Was cobalt released during the event November 21, 2009? Yes, Cobalt was identified in the samples. 2) If so, did Exelon or the NRC attempt to correlate the C0-60 to where the wind was blowing on the day of the release? Yes, the wind was blowing in the Southeast direction that afternoon/evening. 3) Is Exelon or the NRC looking for other depositions or the centerline of the plume? If so, Cobalt-60 has a hard gamma and is easy to find. Exelon has analyzed samples in adjacent sectors. All but the ones identified in the press release indicated less than detectable levels of activity. There is an assumption in the press release that Exelon measured the worst case scenario which may be wrong since this was a ground level release, and building wake effects would keep the plume on the ground and near the plant. 4) Did Exelon check for beta emitters at the sample locations? Yes, the analysis performed at the off-site lab checks for Beta emitters per our program requirements. 5) Also, a Condition Report has been written up on this event. That is disclosable under FOIA. Can you share a copy? The sample results were entered into our Corrective Action Program and will be included in our normal Report. Thank you for your patience throughout the holidays. I hope the information is helpful. I read your recent postings on your website and I am looking forward to discussing the changes to your monitoring system. Please let me know if you need clarification or would like to get together soon. Happy New Year, Alisa Harris-Daniels