ML12160A349
| ML12160A349 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/07/2012 |
| From: | Swift P Constellation Energy Nuclear Group, EDF Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC ME5789 | |
| Download: ML12160A349 (2) | |
Text
CENG a joint venture of Consteltianii Energy NINE MILE POINT NUCLEAR STATION P.O. Box 63 Lycoming, NY 13093 June 7, 2012 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
SUBJECT:
Document Control Desk Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 Request to Utilize an Alternative to the Requirements of 10 CFR 50.55a(g) for the Repair of Control Rod Drive Housing Penetrations - Withdrawal of the Portion of the Request Regarding Rotary Peening (TAC No. ME5789)
(a) Letter from J. E. Pacher (NMPNS) to Document Control Desk (NRC), dated March 25, 2011, Request to Utilize an Alternative to the Requirements of 10 CFR 50.55a(g) for the Repair of Control Rod Drive Housing Penetrations for the Remainder of the License Renewal Period of Extended Operation
REFERENCES:
(b) Letter from P. M. Swift (NMPNS) to Document Control Desk (NRC), dated September 29, 2011, Request to Utilize an Alternative to the Requirements of 10 CFR 50.55a(g) for the Repair of Control Rod Drive Housing Penetrations -
Response to NRC Request for Additional Information (TAC No. ME5789)
(c) Letter from P. M. Swift (NMPNS) to Document Control Desk (NRC), dated April 9, 2012, Request to Utilize an Alternative to the Requirements of 10 CFR 50.55a(g) for the Repair of Control Rod Drive Housing Penetrations - Response to NRC Follow-up Request for Additional Information (TAC No. ME5789)
By letter dated March 25, 2011 (Reference a), as supplemented by letters dated September 29, 2011 (Reference b) and April 9, 2012 (Reference c), Nine Mile Point Nuclear Station, LLC (NMPNS) requested NRC approval of an alternative weld repair strategy for Nine Mile Point Unit 1 Control Rod Drive (CRD) housing penetrations. The alternative repair strategy, described in 10 CFR 50.55a Request Number 1ISI-004, included a variation of the CRD housing penetration welded repair geometry specified in Boiling Water Reactor Vessel and Internals Project (BWRVIP) report BWRVIP-58-A and variations
Document Control Desk June 7, 2012 Page 2 from the requirements of the American Society of Mechanical Engineers (ASME) Code,Section XI, and ASME Code Case N-606-1.
Proposed Alternative No. 6 described in 10 CFR 50.55a Request Number 1ISI-004 requested relief from the restriction in ASME Code Case N-606-1 that prohibits peening of the final weld repair layer. NMPNS proposed using a rotary peening process on the final weld layer as an enhancement to decrease the susceptibility of the weld and adjacent stainless steel CRD housing base material heat affected zone to intergranular stress corrosion cracking. Interactions with the NRC staff on the rotary peening process indicate that there are questions regarding this process that cannot be readily resolved at this time.
Therefore, NMPNS hereby withdraws Proposed Alternative No. 6 regarding rotary peening and requests that the NRC approve 10 CFR 50.55a Request Number 1ISI-004 without consideration of Proposed Alternative No. 6.
This letter contains no new regulatory commitments. Should you have any questions regarding the information in this submittal, please contact John J. Dosa, Director Licensing, at (315) 349-5219.
Very truly yours, Paul M. Swift Manager Engineering Services PMS/DEV cc:
Regional Administrator, Region I, NRC Project Manager, NRC Resident Inspector, NRC