ML021770316
| ML021770316 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/22/2002 |
| From: | Thadani M NRC/NRR/DLPM/LPD4 |
| To: | Head S, Walker P South Texas |
| References | |
| Download: ML021770316 (2) | |
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Re: Comments on STP Response to ILRT Extension RAIs 5/22/02 9:08AM Mohan Thadani MCT@nrc.gov Recipients stpegs.com snmhead (Internet: smhead @ stpegs.corn) nrc.gov owf2_po.OWFNDO DXT CC (David Terao)
EDT 1 CC (Edward Throm)
JCP2 CC (James Pulsipher)
MRS 1 CC (Michael Snodderly)
TMC CC (Thomas Cheng) stpegs.com plwalker (INTernet:pl walker@ stpegs.com)
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Size 2795 Action Transferred Delivered Opened Opened Opened Opened Opened Opened Transferred Delivered 05/22/02 09:09AM Date & Time 05/22/02 09:08AM Date & Time 05/22/02 09:09AM 05/22/02 09:09AM 05/22/02 11:16AM 05/22/02 09:1 1AM 05/22/02 10:45AM 05/23/02 11:25AM 05/22/02 09:34AM 05/22/02 10:17AM 05/22/02 09:09AM Route Internet nrc.gov stpegs.com No None Yes Standard No None No Standard Immediate Delivered & Opened iC-:U1NDOWS\\TEMP\\GW}O0001.TMP
SM-ohan Thadani - Re: Comments on STP Response to ILRT Extension RAIs From:
Mohan Thadani To:
INTernet:plwalker@ stpegs.com; Internet:smhead @ stpegs.com Date:
5/22/02 9:08AM
Subject:
Re: Comments on STP Response to ILRT Extension RAIs Scott/Phillip:
The NRC staff has the following comments on your response to our telecon on ILRT, and would like to set up a telecon to discuss them with your staff.
We agree with the licensee's response to Question 1 that the total LERF is less than 1 E-05 and thus satisfies the requirements of RG 1.174. We disagree with the licensee that the LERF is the sum of the change in LERF from the extension request and the Class 8 frequency (7.3E-07). Based on Table 3, it should be the sum of Class 2, 3b, 8, and some fraction of 7 (<6.1 E-06).
The response to Question 2 does not address those parts of the containment liner that are inaccessible for visual examination. The licensee concludes that containment liner flaws are not expected to contribute to LERF because of the leak-inhibiting aspects of the containment concrete layer. We do not believe that this position is correct, because the pressure increase is likely to cause the crack openings in the concrete to increase and increase the communication between the containment and the outside atmosphere. Both of these issues are addressed by the Calvert Cliffs approach. The STP response to this question does not adequately addresses the concern identified in the RAI.
The licensee, in its response to Question 6, states that potential leakage during core damage accidents as a consequence of liner degradation is not included in the risk assessment related to extension of the ILRT interval. The Calvert Cliffs approach represents a relatively simple way to include degradation of the liner in the risk assessment. That approach can be easily adapted to STP, and doing so would provide a more defensible argument to address RAI 6.
Please let us know when you would like to setup a call to go over the above comments.
Thanks.
Mohan CC:
David Terao; Edward Throm; Hansraj Ashar; James Pulsipher; Michael Snodderly; Thomas Cheng S~Page