ML20215M394

Safety Evaluation Re Request for Relief from Inservice Insp Requirements

ML20215M394
Person / Time
Site:	Hatch
Issue date:	06/22/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20215M377	List: ML20215M373 ML20215M394
References
TAC-64164, NUDOCS 8706260381
Download: ML20215M394 (3)

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SAFE'Y EVALUATION REPORT FOR THE OFFICE OF' NUCLEAR' REACTOR REGULATION RELATED TO A REQUEST FOR RELIEF FROM INSERVICE INSPECTION REOUIREMENTS GEORGIA POWER COMPANY, ET-AL

, HATCH NUCLEAR PLANT, UNIT 1 DOCKET NO.-50-321 l

JTRODUCTION Technical Specification 3.6.K for the Hatch Nuclear Plant, Unit 1 requires that an inservice examination of"ASME' Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable! Addenda as required by 10 CFR 50.55a(g) except where specific written relief.has been granted by the Commission.. Some plants, including Hatch Unit l', were designed in conformance.to early editions of this l Code Section; consequently certain requirements of later editions'and addenda "

j of Section XI are impractical to perform because'of the plant design, component geometry or materials of construction. Regulation 10 CFR 50.55a(g)(6)(1).

authorizes the Commission to grant relief from those ' requirements upon making the. necessary findings.

We have previously provided a Safety Evaluation Report (SER) dated November 7,.

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-1985-(Reference 1) in regard to the licensee's relief. requests from certain l inspection requirements. In that SER we concluded that Relief Request 4.1.2 {

should be granted for the plant' service water system for the first 10-year 1 inservice inspection interval only. l By letter' dated November. 14, 1986'(Reference 2). Georgia Power Company (GPC),

submitted a revised Relief Request 4.1;2 including other piping systems which  !

cannot be tested in accordance'with the requirements of ASME Code,Section XI, paragraph IWA-5244 (e.g., plant service water, RHR. service water, RCIC pump suction,andHPCIpumpsuction). GPC had determined that the portions of the

-systems that are buried are impractical to test and examine at the Hatch Nuclear Plant Unit 1.

The applicable ASME Code requirement, 4.1.2 " System Pressure Tests on ASME Class 3 Buried Piping" is:

Code Requireme'nt-Table IWD-2500-01' stem pressure of ASME Code, test for Class 3 components, Section including XI requires buried piping. a sy(D1.10, D2.10, '

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l The licensee has requested relief from the code as follows: ,

Relief is requested from system pressure tests for Class 3 buried piping  !

sections of the following systems: 1

a. Plant service water from valve pit at intake structure to the Diesel Generator Building and the Reactor Building.

b. RHR service water from the valve pit at intake structure to Reactor Building,

c. RCIC pump suction from IE51-F009 to IE51-F010.

d. HPIC pump suction from IE41-F010 to IE41-Foo4.

Licensee's Proposed Alternative Examination Required pump operability testing done quarterly demonstrates the integrity of the buried piping by proving that the required flow is available for the RHR service water, HPCI, and RCIC systems. A large break in buried piping would be detected in the plant service water system, which is a normally operating system, by its effect on the flow to equipment downstream of the. break. Some non-safety related systems (demineralized water, etc.) draw from the condensate storage tank (CST) and are considered as part of the Class 3 boundaries of the tank. Because of the condensate storage tank (CST) design, a break in these non-safety related systems would not reduce the level of the volume in the CST below the minimum reserve safety-related volume.

Licensee's Basis for Requesting Relief The systems (e.g., plant service water, RHR service water, RCIC pump suction and HPCI pump suction) which cannot be tested in accordance with the require-ments ASME Code,Section XI, Paragraph IWA-5244 were designed without including provisions for the testing of buried piping as required by Paragraph IWA-5244.

In addition, the visual examination for leakage at ground level is not feasible, since the majority of the piping is buried under asphalt.

Evaluation .

l The RHR service war system, HPCI and the RCIC systems are required to have I pump operability testsa r'one quarterly. Part of this test is to show that the pumps can provide ti.: required flow which in turn demonstrates that the buried piping has adequate integrity to provide the required pressure boundary for this flow. Similarly, in the plant service water system, which is a i

nonnally operating system, any break in the piping boundary would reduce the I i

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1 flow to equipment downstream of the break. Reduced flow to this equipment '

downstream would degrade the equipment performance and signal the break. The non-safety related systems (demineralized water, etc.) draw water from the condensate storage tank. Because of the design of the condensate storage tank, a break in the non-safety related systems would not reduce 'the stored volume in the tank below the required minimum reserve safety-related volume. In addition, the water level of the condensate storage tank is monitored daily.

This portion of the plant service water piping has butterfly valves installed i on either end of the buried portion, as has the RCIC pump suction and the HPCI {

pump suction. Butterfly valves are not suitable for maintaining pressure, l 1.e. not leak tight..during a pressure decay test. The RHR. service water has gate valves on either end of the buried piping but has no pressure taps (

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1 available in between these valves and thus cannat perform a pressure decay '

test.

i Since the service water, demineralized water and core spray systems do not l have provisions for testing buried piping and visual examination for leakage 1 at ground level is not feasible, the Code-required examinations are {

impractical. The licensee's proposed. system functional testing and monitoring '

are reasonable substitutes for the Code-required examinations.

Conclusions Based upon the above, it is concluded that, for the buried pressure retaining piping. plant service water, RHR service water, RCIC pump suction, and HPCI pump suction, the Code requirements discussed above are impractical. It is further concluded that the system functional testing and monitoring will provide assurance of structural reliability. Therefore, relief is granted from performing the Code-required examinations on the above buried pressure retaining piping during the first ten-year interval only.

References

1. Letter from H. Denton, NRC, to J.T. Beckham, GPC dated November 7,1985

2. Letter'for L.T. Gucwa, GPC, to D. Muller, NRC, dated November 14, 1986 i

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