ML20094G677
| ML20094G677 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 02/26/1992 |
| From: | Floyd S CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NLS-92-046, NLS-92-46, NUDOCS 9203030241 | |
| Download: ML20094G677 (5) | |
Text
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Carolina Power & Light Company Nuclear Services Department 411 rayettetille Street Mall-P.O. Box 1551 Raleigh, North Carolina 27602
[FEB 261992 SERIAL: NLS 92-046 United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO.1 DOCKET NO. 50-325/ LICENSE NO. DPR-71 ASME CODE RELIEF REQUEST -INSERVICE INSPECTION PROGRAM MAIN STEAM RELIEF VALVE PRESSURE TEST Gentlemen:
The purpose of this letter is to request relief from the ASME Code,Section XI, in accordance with 10 CFR 50.55a(g)(6)(i), for the Brunswick Steam Electric Plant, Unit 1.
The ASME Code relief is needed to support a plant modification to replace the existing main feedwater containment isolation check valves.
A plant modification to replace the existing main feedwater containment isolation check valves will be performed (during the Unit 1 refueling outage) to correct the continuing local leak rate failures being experienced with the valves. To support the modification, a portion of the discharge piping for the F013H main steam safety / relief valve will be temporarily removed and subsequently re-installed. The ASME Code,Section XI, Subparagraph IWD-5223(f) requires a pneumatic test (at a pressure of 90 percent of the pipe submergence head of water) for the relief valve piping that discharges into the centcinment cuppression poo!. The reque'cM re!!ef een!ies to the main steam relief valve discharge piping that connects between safety / relief valve F013H and the containment suppression pool. The proposed alternate testing (volumetric weld examination) will provide adequate assurance of the integrity of the affected piping.
The detailed re'ief request is provided in Enclosure 1. Approval of this relief request is needed by September 1,1992 in support of the Brunswick Unit 1 refueling outago scheduled to begin September 12,1992. A similar request for the Brunswick Steam Electric Plant, Unit 2 was submitted by CP&L letter dated August 15,1991 (Serial: NLS-91-198) and was approved by NRC letter dated October 29,1991, t
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e Docunient Control Desk NLS-92-046 / Page 2 Please refer any q.astions regarding this submittal to Mr. W. R, Murray at (919) 546-4661.
Yours very truly, S. D. floy Manager Nuclear Licensing Section WRM/wrm (b1r8relf.wpf)
Enclosure cc:
Mr. S. D. Ebneter Mr. N. B. Le Mr. R. L. Provatte
ENCLOSURE 1 BRUNSWICK STEAM ELECTRIC PLANT, UNIT 1 NRC DOCKET NO. 50-325 OPERATING LICENSE NO. DPR 7 l ASME CODE RELIEF REQUEST -INSERVICE INSPECTION PROGRAM MAIN STEAM RELIEF VALVE PRESSURE TEST l.
APPLICABLE COMPONENTS This relief request applies to the main steam relief valve discharge piping that runs between safety / relief valve F013H and the containment suppression pool.
A portion of the piping betWHm c3fetv!re!ief 'ralve F013H and the containment suppression pool will be removed and subsequently re-installed (during the Unit 1 refueling outage as part of a plant modification replacing the existing feedwater j
check va?ves.
II.
IMPRACTICAL TEST REQUIREMENT The Technical Specifications for the Brunswick Steam Electric Plant, Unit 1 state that inservice inspection of ASME Code Class 1,2, and 3 components shall be performed in accordance with the requirements of the applicable edition and addenda of the ASME Code,Section XI except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). The Section XI Code edition and addenda applicable to the Brunswick Steam Electric Plant, Unit 1 are the 1980 Edition with Addenda through the Winter 1981.
The ASME Code,Section XI,IWA-4000 provides requirements for repairs to pressure retaining components. IWA-4400(a) requires the performance of a system hydrostatic test in accordance with IWA 5000 fnllowing wolding repairs.
IWA-5214(a) and IWA-5214(b) require the pressure test requirements comply with IWD-5223 for Class 3 components. IWD 5223(f) requires a pneumatic test (at a pressure of 30 percent uf the pipe submergence head of water) for safety or relief valve piping which discharges into the containment pressure suppression pool in lieu of a system hydrostatic test.
Ill.
BASIS FOR REllEF A plant modification to replace the existing main feedweter containment isolation check valves (will be) performed to correct the continuing local leak rate test failures being experienced with the valves. To support the modification, a portion of the discharge piping for the F013H main steam safety / relief valve (will be) temporarily removed and subsequently re-installed, as shown in the attached E1-1 L-a 2_____
. isometric drawing from the plant modification package. The affected discharge piping is located in the drywell portion of the primary containment.
As described above, subparagraph IWD 5223(f) of the ASME Code,Section XI requires a pneumatic test at a pressure of 90 percent of the pipe submergence head of water (i.e.,2.8 psi). The centerline of the tee-quencher for the relief valve discharge piping is 7.25 feet below the high water levelin the containment suppression pool. Therefore, the test pressure corresponding to 90 percent of the pipe submergence head of water, as required by the ASME Code,Section XI, subparagraph IWD-5223(f), is 2.8 psi, e
implementation of the modification is currently being scheduled after performance of a chemical decontamination of the recirculation system piping. Nevertheless, approximately 0.3 man-rem of personnel radiation exposure savings can be realized by not performing the pneumatic test in accordance with IWD-5223(f).
Performance of the pneumatic pressure test will require disassembly of the F013H safety / relief valve in order to pressure the piping to the 2.8 psi test pressure and perform the examination. The design pressure and temperature for the piping is 450 psig and 560 degrees F. The test pressure required by IWD-5223(f)
(i.e.,2.8 psi) is significantly lower than the design pressure of the piping and the operating pressure typically experienced by the piping; therefore, the Company does not believe the IWD-5223(f) test provides assurance of the integrity of the piping commensurate with the personnel exposure associated with performance of the test. Based on the estimated personnel radiation exposure to perform this test, as well as the potential for inadvertently damaging the F013H safety / relief valva, the Company believes the test requirement is impractical and requests relief in accordance with 10 CFR 50.55a(g).
IV.
ALTERN ATE TESTING The field welds will be examined to the most stringent optional requirement of the ASME Code, Section lil, Class 3_(i.e., using RT examination). Based on the alternate testing, it is highly improbable that a weld that passes a volumetric examiriatiunivil1 leak at o test pressure of 2.8 pci (a test pressura cf 90 percent of the pipe submergence head of water).
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