ML18152B181
| ML18152B181 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 06/17/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18152B180 | List: |
| References | |
| NUDOCS 8807050142 | |
| Download: ML18152B181 (3) | |
Text
,.
e UNITED STATES e
NUCLEAR REGULATORY COMMISSION.
WASHINGTON, D. C. 20555 ENCLOSURE SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR RELIEFS FROM HYDROSTATIC TEST REQUIREMENTS FOLLOWING VALVE REPLACEMENTS VIRGINIA ELECTRIC AND POWER COMPANY SURRY PmlER STATION UNITS 1 AND 2 DOCKET NOS. 50-280 AND 50-281 I.
BACKGROUND INFORMATION By letter dated February 13, 1987, Virginia Power Company (the licensee) informed the NRC of the replacement of three isolation valves at Surry Units 1 and 2 during outages in February 1987 and October 1986, respectively. The licensee provided information concerning the replacements and requested relief from the hydrostatic pressure test requirements of the 1980 Edition through Winter 1980 Addenda of Section XI of the ASME Boiler 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 1 s request, supporting.infor-mation, and alternative examinations or tests as well as the staff 1 s bases for granting the request.
I I.
RELIEF _REQUESTED, SUPPORTING INFORMATION, AND EVALUATIONS A.
Relief Request - Relief was requested from the hydrostatic test requTrements-following the replacement of a four (4)-inch manual iso-lation valve, 2-MS-86, that isolates the "A" steam generator power operated relief valve (PORV) in Unit 2.
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 delineates that the system pressure Psv shall be the lowest pressure setting among the number of safety or relief valves providt::d for overpressure protection within the boundary of the system to be tested. The system pressure for the piping containing the welds requir~d to be hydrostatically tested is 1085 psig and, therefore, the test pressure is required to be 1356 psig.
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e 2
Licensee's Boses_for_Request~_Relief The licensee stated that the welds required to be tested cannot be isolated from tht::
11A 11 :,team generator (2-RC-E-lA), thereby placing it within the hydrostatic t~st boundary.
The licensee further stated that hydrost~tic tests which include steam generators are extremely difficult and deemed imprdctical when compared to other possible a lterndtives.
Licens~e*s Proposed Alternatives The licensee proposed the volumetric (RT) and surface examinations (PT) performed on the w~lds as alternativts to the Code-requirtd hydrostatic test. The welds were visually inspected during normal operations and no leakage was detected.
Staff Evaluation and Conclusion The valve replaced is a 4-inch manual isolation valve used to iso-late tht steam generator 11A 11 PORV for maintenance purposes.
The re-placement valve cannot be isolated from the steam generator 11A 11 secon-dary side and imposition of the hydrostatic test requirements would therefore necessitate pressurizing the steam generator and main stea~
piping to approximately 1356 psig.
Pressurizing the steam generator to an additional test cycle that was not accounted for in its design life is impractical and unwarranted when the licensee's proposed alternative examinations, inspections, and the Code-required welding procedures are considered.
The licensee proposed radiography and surface examinations of the two welds joining the valve ~nd piping.
In addition, the welds were visually inspected during normal plant operation with no leakag~
detected.
The staff finds that the requirements of the Code are impractical ano will unnecessarily burden licensee's equipment.
The proposed nondestructive examinations and the leakage test are adequate to assess the structural integrity of the welds made in replacing the manual isolation valve 2-MS-86.
We therefore conclude that relief from the Code hydrostatic test requirements may be granted as requested *.
B.
Rel!.~f_Rt:g!!~t -
Relief \\*/as requested from the hydrostatic test requirements tallowing the replacement of a 2-inch steam generator nitrogen isolation valv~, l-GN-3, and a li-inch main steam drain isolation valve, 1-MS-80 in Unit 1.
Code_Re9!!irement ASME Section XI, Subarticle IWA-4400, requires a hydrost~~j~ 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 delineates that the syst~m pressure Psv shall be 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 these valves is 1085 psig, therefore, the test pressure required is 1356 psig.
e 3
Licensee 1s Bdses_for_Request1n9 ~elief The licensee stated that the Code-required' hydrostatic test would place the "A" and "C" steam generators (1-RC-E-lA and 1-RC-E-lC) within the test boundary.
Hydrostatic tests which include steam generators are extremely difficult and deemed impractical when compared to other. possible alternatives.
Licensee 1 s Proposed_Alternative The licensee proposed surface (PT) and visual (VT-21 examinations of the welds as alternatives for the Code required hydrostatic test.
Staff Evaluation and Conclusion The valves replaced by the licensee are Class 2, 2-inch and It-inch valves used to isolate nitrogen and a main steam drain, respectively.
The location of these valves necessitates pressurizing the steam generators in order to comply with the Code hydrostatic test requirements.
Imposition of the Code requirements on the licensee would cause the steam generators to be subjected to additional test
- cycles that were not accounted for in their design.
Th~ licensee proposed surface examinations and visual inspections 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 requirem~nts of the Code are impractical ana will unnecessarily burden licensee 15 equipment.
The proposed nondestructive examinations and the visual inspection of the welds are adequate to assess weld structural integrity.
We therefore conclude that relief from the Code hydrostatic test requiremtnts may be granted as requested.
The staff has determined that based on the alternatives propo5td, the relief requested by the licensee may be granted, as described above, pursuant to 50.55a(g)(6)(i). With respect to the above rlief requests, the staff has determined that the requirements uf the Code aie impractical and the relief granted is authorized by law and wi 11 not endanger life or property or the common defense and stcurity 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.
Doted:
June ll, 1988 f!incieal Contrib~to.!:.:
G. Johnson
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