ML20217E922
| ML20217E922 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/25/1998 |
| From: | Saunders R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 98-123, NUDOCS 9803310206 | |
| Download: ML20217E922 (2) | |
Text
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has 4 Eu:crRic AND POWER COMI%NY menuoNo, VimnN A 23261 March 25, 1998 Document Control Desk Serial No.98-123 U. S. Nuclear Regulatory Commission NLOS/ETS:
R0 Washington, D. C. 20005 Docket Nos.
50-338 50-339 License Nos.
NPF-4 NPF-7
Dear Sir:
ylBrilNIA ELECTRIC AND POWER COMPANY NORTE ANNA POWER STATION UNITS 1 AND 2 EBQIECTION AGAINST DYNAMIC EFFECTS ASSOCIATED WITH THE POSTULATED RUPTURE OF HIGH ENERGY _ PIPING OUTSIDE CONTAINMENT in our letter dated September 23,1996 (Serial No.96-444), we informed the NRC of our intent to modify the inspection program performed at North Anna to preclude high energy piping ruptures outside containment. Specifically, we proposed modifying our current commitment by replacing the augmented inservice inspection program for the Main Steam and Feedwater Systems in the Mechanical Equipment Room with our Secondary Piping and Component inspection Program (flow-accelerated corrosion program).
Implementation of the current augmented inspection program and the Secondary Piping and Component inspection Program for the Main Steam and Feedwater System was discussed with the NRC staff on March 16,1998. As a result of that discussion, we are modifying our proposed commitment change. In addition to the Secondary Piping and Component inspection Program, we will continue to implement an augmented weld inspection program for the identified potential break point locations in the Main Steam and Feedwater Systems piping located in the Mechanical Equipment Room, but at a reduced percentage. Twenty-five percent of the potential break point weld locations in the Main Steam and Feedwater Systems piping located in the Mechanical Equipment Room will be examined each inspection period in accordance with the rules of ASME Section XI, subsection IWC (Class 2), edition and addenda corresponding to the current approved ASME Section XI program (currently the 1983 edition and Summer 1983 addenda for North Anna Unit 1 and the 1986 edition for North Anna Unit 2). The inspection locations will be changed each ASME Section XI inspection period, such that a different twenty-five percent of the weld locations will be inspected. Therefore, seventy-five percent of all welds will be inspected each ten year interval.
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The proposed modification addresses an NRC staff question regarding the potential for future age-related damage mechanisms at the welds. The proposed percentage of augmented inspi ns is equivalent to three times the examination percentage required for ASM,
.; ass 1 Category B-J piping welds in Section XI. As such, piping weld integrity continues to be adequately assured by the proposed augmented inspection program.
Should you have any questions or require additional information, please contact us.
Very truly yours, R. F. Saunders Vice President - Nuclear Engineering and Services Commitments made in this letter:
Twenty-five percent of the potential break point weld locations in the Main Steam and-Feedwater Systems piping located in the Mechanical Equipment Room will be examined each inspection period in accordance with the rules of ASME Section XI, subsection IWC (Class 2).
cc:
United States Nuclear Regulatory Commission Regional Administrator - Region II Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303 Mr. M. J. Morgan NRC Senior Resident Inspector North Anna Power Station i
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