ML18152B055
| ML18152B055 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/08/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18152B054 | List: |
| References | |
| NUDOCS 8807190293 | |
| Download: ML18152B055 (2) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUES1J:OR RELIEF FROM HYDROS~~TIC_TEST REQUIREMENTS FOLLOWING VALVE REPLACEMENT VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 1 DOCKET NO. 50~280 I.
BACKGROUND INFORMATION ENCLOSURE By letter dated October 6, 1987, Virginia Electric and Power Company (the licensee) informed the NRC of the replacement of a 4-inch isolation valve located in the main steam system at Surry Unit 1 during an unplanned outage in October 1987.
The licensee provided information concerning the replacement and requested relief from the hyd_rostatic pressure test requireme.n.ts of the 1980 Edition through Winter 1980 Addenda of Section XI'of the ASME~oiler and Pressure Vessel Code pursuant to 10 CFR 50.55a(g)(5)(iii).
In accordance with 10 CFR 50.55a(g)(6)(i), this report provides an evaluation of the licensee's request, supporting information, and alternative examinations or tests as well as the staff's bases for granting the request.
II.
RELIEF REQUESTED, SUPPORTING INFORMATION, AND EVALUATION A.
Relief Request - Relief was requested from the hydrostatic test requirements following the replacement of a 4-inch manual isolation valve, 1-MS-86, that isolates the 11A 11 steam generator power operated relief valve (PORV) in Unit 1.
Code Requirement (1980 Edition, Winter 1980 Addenda)
ASME Section XI, Subarticle IWA-4400, requires a hydrostatic test to be performed after repairs by welding*on a pressure retaining boundary of Code Class 1, 2, and 3 piping or components.
The Code requires the system hydrostatic test pressure to be at least 1.25 times the system pressure Psv for systems with design temperature above 200°F.
The Code defines the system pressure, Psv, as the lowest pressure setting among the number of safety or relief valves provided for overpressure protection within the boundary of the system to be tested. The system pressure for the piping containing the welds required to be hydrostati-cally tested is 1085 psig and, therefore, the test pressure is required to be 1356 psig.
2 Licensee's Bases for Requesting Relief The licensee stated that the hydrostatic test required by the Code would encompass the "A" steam generator and a large section of attached main steam piping within the hydrostatic test boundary.
The licensee further stated that this test is considered extremely difficult and impract"ica 1.
Licensee's Proposed Alternatives The licensee proposed that a surface examination (PT) be performed on the final welds as an alternative to the Code-required hydrostatic test.
In addition, the licensee proposed to perform a system pressure test (IWC-5221) in conjunction with a VT-2 examination.
Staff Evaluation and Conclusion The valve replaced is a 4-inch manual isolation valve used to isolate the steam generator "A" PORV.
The replacement valve cannot be isolated from the steam generator "A" secondary side and imposi-tion of the hydrostatic test requirements would therefore necessitate pressurizing the steam generator and main steam piping to approxi-mately 1356 psig.
Pressurizing the steam generator to an additional test cycle that was not accounted for in its design life is imprac-tical and unwarranted when the licensee's proposed.a.,lternative examination, inspection, and the Code-required welding procedures are considered.
The licensee proposed a surface examination and a visual inspection of the welds as alternatives to the hydrostatic test, the visual inspec-tion to be performed during a system functional test. The staff finds the requirements of the Code are impractical and will unnecessarily burden licensee's equipment.
The proposed nondestructive examination and the visual inspection of the welds are adequate to assess the structural integrity of the welds made in replacing the manual isolation valve 1-MS-86.
We therefore conclude that relief from the Code hydrostatic test requirements may be granted as requested.
The staff has determined that based on the alternatives proposed, the relief requested by the licensee may be granted, as described above, pursuant to 50.55a(g){6)(i). With respect to the above relief request, the staff has determined that the requirements of the Code are impractical and the relief granted is authorized by law and will not endanger life or property or the common defense and security and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the require-ments were imposed on the facility.
Dated:
July 8, 1988 Principal Contributor:
C. Patel