ML103210138
| ML103210138 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 11/08/2010 |
| From: | Peter Bamford Plant Licensing Branch 1 |
| To: | Stewart G Exelon Corp |
| bamford p | |
| References | |
| Download: ML103210138 (2) | |
Text
From:
Bamford, Peter Sent:
Monday, November 08, 2010 1:11 PM To:
'glenn.stewart@exeloncorp.com'
Subject:
Limerick RHRSW Call - RAI Follow-up Questions Glenn here are the questions regarding the RHRSW RAI response Id like to discuss tomorrow, if possible:
1.) Response to 8c: The issue here was that the commitment to verify the system alignments periodically was not described as to how it would be accomplished. In their response, the licensee has only restated the intent to periodically verify the alignment.
The NRC staff still does not know or have a commitment which tells us how the licensee is physically accomplishing this - i.e., will the licensee run a test, do flow verification, or simply check some valves and breakers, or are they going to verify every component is properly aligned including local valves, etc.?
2.) Response to 8e: The issue was that the commitment has not adequately clarified the meaning of switchyard activities that adversely affect risk exposure. In their response, the licensee has stated that these are activities which have the potential to cause a total loss of offsite power. It is still not clear as to what this includes, and the NRC requests that the licensee be more specific.
3.) Response to RAI 6b, regarding multiple spurious actuations modeling assumptions: The licensee identifies that a site review of multiple spurious operations (MSO) scenarios was conducted, and that MSOs of concern were entered into the corrective action program. The licensee then states that ultimately these items will be dispositioned by hardware changes or viable operator actions, and that this approach, in consideration of the low probability of MSOs, ensures a negligible impact on the fire PRA and the delta risk calculations. The low probability of MSOs is not an acceptable justification for neglecting their impact on a risk calculation, and any future changes to plant configuration or operation to disposition an MSO has no impact on the risk calculations done to support this application. Therefore, the licensee needs to justify that those MSOs entered into the corrective action program are not significant for the risk calculations performed in support of this request.
Bridge info for tomorrows call Date/Time: Tuesday 11/09/2010, 1:00 PM EST Bridge No: 888-566-6178 Passcode: 29756#
Peter Bamford NRR/DORL/LPL 1-2 Limerick & TMI-1 Project Manager 301-415-2833 The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.
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Subject:
Limerick RHRSW Call - RAI Follow-up Questions Sent Date: 11/8/2010 12:45:04 PM Received Date: 11/8/2010 1:11:00 PM From: Bamford, Peter Created By: Peter.Bamford@nrc.gov Recipients:
glenn.stewart@exeloncorp.com ('glenn.stewart@exeloncorp.com')
Tracking Status: None Andrew.Howe@nrc.gov (Howe, Andrew)
Tracking Status: None Post Office:
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