ML18153B912
| ML18153B912 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 10/02/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18153B911 | List: |
| References | |
| NUDOCS 8910060022 | |
| Download: ML18153B912 (2) | |
Text
UNITED STATES e
NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RELIEF REQUEST FROM HYDROSTATIC TEST REQUIREMENTS VIRGINIA*ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNIT NO. 2 DOCKET NO. 50-281
1.0 INTRODUCTION
By letter dated August 29, 1989, Virginia Electric and Power Company (the*
licensee) requested relief from the hydrostatic pressure test requirements of the 1980 Addenda of Section XI of the ASME Bailer and Pressure Vessel Code pursuant to 10 CFR 50.55a(g)(5)(iii) at Surry Unit 2.
In accordance with 10 CFR 50.55a(g)(6)(i ), this report provides an evaluation of the licensee'~
request, supporting information, and alternative examination or tests as well as the staff's basis for granting the request.
- 2. 0 EVALUATION Relief Request - Relief was requested-from t.he hydrostatic-test requirements following the replacement of a 3-inch non-return valve, NRV-MS-202B.
Code Requirement - (1980 Edition, Winter 1980 Addenda) - ASME Section XI, sub-article 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 compor,ents.
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 d~lineates that the system pressure, Psv, shall be the lowest pressure setting among the number of safety or relief valves provid~d for overpre5sure protection within the boundary of the system to be tested.
The systt:m pressure for the piping containing the welds required to be hydrostati-cal ly tested is 1085 psig and, therefore, the test pres5ure is required to be 1356 psig.
Basis for Relief - During the Surry Unit 2 refueling outage, an inspection on the internals of a 3-inch non-return valve, NRV-MS-2028, showed Sdnd inclusions in the valve body *. Replacement of the valve was judged to be an appropriate resolution to the problem.
Following replacement by welding, the Code requires that a hydrostatic test be parformed with a corresponding visual (VT-2) examination on the welds in the affected area.
As no intermediate isolation exists, the Code r1:quirement would place the "B" steam generator (2-RC-E-18) within the test boundary.
Hydrostatic tests in an ar*ea to include the steam generator are extremely difficult and are considered impractical by the licensee.
Alternative Examination - As an alternative to the Code requirement, a volumetric examination (RT) and a surface examination (PT) wi 11 be performed on the welds.
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' Summary - The replaced valve cannot be isolated from the secondary side of the steam generator, and imposition of the hydrostatic test (as required by the ASME Code) would necessitate pressurizing the steam piping to about 1356 psig in order to test the attachment welds for the 3-inch non-return valve. Alternatively, the licensee has proposed and committed to perform volumetric and surface examination of these 3-inch welds.
CONCLUSION The alternative examinations will provide reasonable assurance of the structural integrity of the valve replacement welds in the main steam system.
The staff has determined that, based on the alternatives proposed, the relief requested by the licensee may be granted, as described above, pursuant to 10 CFR 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 wi 11 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 requirerrents were imposed on the facility.
Dated: October 2, 1989 PrinciEal Contributors:
Felix itton Darrell Roberts