ML100780357
| ML100780357 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/23/2009 |
| From: | Cullingford M Office of Nuclear Reactor Regulation |
| To: | Peter Bamford Plant Licensing Branch 1 |
| References | |
| FOIA/PA-2010-0118 | |
| Download: ML100780357 (1) | |
Text
Bamford, Peter From:
Cullingford, Michael Sent:
Monday, November 23, 2009 10:13 AM To:
Bamford, Peter
(/v.*...
Subject:
RE: 11/21/2009 TMI Contamination Control Event Peter: Thank you.................. mike From, Bamford, Peter Sent: Monday, November 23, 2009 10:03 AM To: Cullingford, Michael Cc: Glitter, Joseph; Chernoff, Harold; Nelson, Robert
Subject:
11/21/2009 TMI Contamination Control Event Mike, Joe Glitter asked me to send you a summary of the subject TMI event as we know it today. Based on what we know, it is likely that this event would not even be rated on the INES scale. No operating limit was exceeded and no contamination outside the containment building has been detected.
Approximately at 4 PM Saturday 11/21 TMI had an event involving loss of contamination control inside containment. At the time the reactor was defueled with a hole cut in the containment wall to support the ongoing SG replacement outage. The licensee is not sure at this time what activity inside containment led to the problem. Their investigation is focusing on two activities (1) "A" piping loop decontamination activities or (2) some work on a drain line on the B" SG.
At the time of the event 175 workers were inside containment. Of these workers 151 people were selected for detailed monitoring based on nasal smears and portal monitor readings. Of the 151, preliminarily, about 19 people have potentially received doses greater than 10 mR.
The highest dose to a worker was approximately 38 mR, far below the yearly NRC limitof 5000 mrem. No site worker left the site with external contamination.
Airborne contamination levels inside containment have been restored to pre-event levels and cleanup of containment surfaces is in progress. The tarp that was covering the containment opening was contaminated on its inside surface and is in the process of being replaced.
With the open equipment hatch and the SG opening there was the potential for a release outside of containment. At the time of the event a slight positive pressure existed in containment. This has now been corrected to what it should be, ie a slightly negative pressure. Based on readings from radiation monitors present at the SG opening and the duration of the positive pressure, the estimates of release levels are still less than one percent of the quarterly limit in the licensee's offsite dose calculation manual.
Peter Bamford NRR/DORL/LPL 1-2 Limerick & TMI-1 Project Manager 301-415-2833 48