ML11188A194
| ML11188A194 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/28/2011 |
| From: | Swift P Constellation Energy Nuclear Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML11188A194 (2) | |
Text
P.O. Box 63 C ENG.
Lycoming, NY 13093 a joint venture of Constellation eDF Energy' NINE MILE POINT NUCLEAR STATION June 28, 2011 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION:
Document Control Desk
SUBJECT:
Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 Reactor Pressure Vessel Head Weld Flaw Evaluation In accordance with the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Subsection IWB-3610 (2004 Edition), Nine Mile Point Nuclear Station, LLC (NMPNS) is submitting for NRC staff review and approval the attached structural flaw evaluation of a subsurface flaw indication found in a Nine Mile Point Unit 1 reactor pressure vessel (RPV) closure head weld.
Ultrasonic examinations performed during the 2011 refueling outage (RFO21) identified a subsurface flaw indication in weld RV-WD-001, located between the head flange and the closure head. The indication was characterized in accordance with ASME Section XI, Subsection IWA-3320 and Figure IWA-3320-1, as a subsurface planar flaw. Supplemental inspections and reviews conducted by NMPNS provide reasonable assurance that the flaw indication is related to original fabrication and is not service induced.
Flaw characteristic calculations were performed to determine acceptability on the basis of ASME Section XI, Subsection IWB-3500, Paragraph IWB-3510.1. The flaw was initially dispositioned as unacceptable.
Further analytic evaluation, performed in accordance with Subsection IWB-3600, demonstrates that the weld containing the flaw is acceptable for continued service. The calculation provided in the Attachment documents the closure head weld flaw evaluation.
Document Control Desk June 28, 2011 Page 2 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,
'--->-O 4ý( %2--A Paul M. Swift Manager Engineering Services PMS/DEV
Attachment:
Nine Mile Point Unit 1 - Calculation SOVESSELM035 (SIA File No. 1100566.301),
Reactor Pressure Vessel Head Flaw Evaluation, Revision 00.00 cc:
Regional Administrator, Region I, NRC Project Manager, NRC Resident Inspector, NRC