ML20133G496

Safety Evaluation Supporting Rev 4 to First 10-yr Inservice Insp Program & Granting Relief from Hydrostatic Testing Requirements of ASME Code

ML20133G496
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	07/30/1985
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20133G485	List: ML20133G484 ML20133G496
References
NUDOCS 8508080709
Download: ML20133G496 (3)

Text

- -- ___ ______

ENCLOSURE SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO OPERATION OF ZION NUCLEAR POWER STATION UNIT NOS 1 AND 2 COMMONWEALTH EDISON COMPANY DOCKET N05. 50-295 AND 50-304 INTRODUCTION By letter dated May 13, 1985 Componwealth Edison Company submitted a proposed revision to the First Ten Year Inservice Inspection Program (IS! Progrem) for Zion Nuclear Power Station Units 1 and 2. The proposed revision requests relief from certain hydrostatic testing requirements contained in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) 1980 Edition including revisions through Winter 1981 Addenda for buried-portions of Service-Nater System (SWS) piping.

This Safety Evaluation documents a review of the requested revision and its impact on the operation and administration of plant activities.

. EVALUATION Description of Chanae Relief was requested from performance of hydrostatic pressure tests in the buried sections of SWS lines OSW013-48", OSWO14 48", OSW001-12", and OSW008-10". Alternative testing in the form of verification of no flow impairment was proposed.

Evaluation Lines OSWO13-48" and OSWO14-48" run from the connon discharge headers of the Unit 1 and Unit 2 Service Water Pumps respectively to the Auxiliary Building and the Unit 1 and Unit 2 Diesel Generator Buildings. As such, these lines supply service water to various safety related components.

Line OSW001-12" is a SWS supply loop running from lines OSWO13-48" and OSWO14 88" to the Unit 1 Diesel Generator Building. This loop supplies service water to the intercoolers, jacket water coolers, and lube oil coolers on the safety related OA,1A, and IB Diesel Generators.

Line OSW008-10" is a SWS supply loop running from lines OSW013-48" and 05WO14-48" to the Unit 2 Diesel Generator Building. This loop supplies service water to the intercoolers, jacket water coolers, and lube oil coolers on the safety related 2A and 2B Diesel Generators.

All of the above lines are buried. Each is separated from other portions of the SWS by sectionalizing butterfly valves.

Subsection IWA-5244 of Section XI of the 1980 Edition of the ASME Code specifies the following nonredundant system pressure test requirements for buried components: 8508080709 850730 PDR ADOCK 05000295 )

G PDR

_. _ ... . . . . . . - .. = . .

1 i-

a. In nonredundant systems where the buried components are isolable by means of valves, the usual examination shall consist of a leakage test that detemines the rate of pressure loss. Alternatively, the test may detemine the change in flow between the ends of the buried components. The acceptable rate of pressure loss or flow shall be l established by the owner.

b. In nonredundant systems where the buried components are non-isolable,

, such as return lines to a heat sink, the visual examination sht11 consist only of a verification that the flow during operation is not impaired. -

l The licensee's current ISI Program specifies testing of the subject SWS lines in accordance with Item a above. According to the licensee, system sectionalizing valve leakage prevented satisfactory completion of pressure

- drop testing. Detemination of the flow at both ends of the buried lines is not possible due to the lack of sufficient lengths of straight piping in the as built configuration. Consequently, the existing pressure test requirements cannot be satisfied. As an alternative, the licensee has proposed to tesFthe subject SWS lines in accordance with Item b above.

. The test methods described in Item a above would yield a quantitative measurement of through wall line leakage and consequently line integrity. The. test method described in Item b above provides a qualitative assessment as to system flow capability. As such, the two methods might not provide equivalent levels of assurance as to system conditions. To resolve this situation, additional information was 1

requested of the licensee in the details of how the proposed testing would be performed and any other testing being perfomed which would j demonstrate system conditions.

9 By telephone, on June 7, 1985 the reviewer was provided with the following

] clarification by the licensee's Zion Station Nuclear Licensing Administrator:

a. The proposed testing would be perfomed by detemining the flow to 3 certain major components supplied cooling water through the subject lines. Specifically, flow to the Containment Fan Coolers would be measured using noma 11y installed instrumentation. Flow to the

Component Cooling Water Heat Exchangers and the Diesel Generator i coolers would be derived by performing heat balances on these com- l ponents. Degradation in these flows would result in an investigation into potential causes including SWS line deterioration. Thus, a quantitative measurement of system perfomance would be obtained.

i

b. On a monthly basis, a surveillance test of the SWS is performed 1

which requires, in part, that the pressure in a comon header downstream of the subject piping be measured, recorded, and evaluated. Degradation in measured pressure would result in an investigation into potential causes. including SWS line deterioration.

4 i

2' l

c. SWS flow to various components is routinely monitored.

Deterioration in monitored flow would result in an investigation of the cause.

The staff finds the licensee's proposed alternative testing acceptable for the following reasons:

a. Section IWA-5244 of Section XI of the 1980 Edition of the ASME Code allows the testing proposed by the licensee for non-isolable buried components. While sectionalizing butterfly valves are provided in  ;

the lines of interest, they provide fault isolation, not pressure isolation.

b. Extension of the boundary to be tested to existino valves capable of pressure isolation is not feasible due to the large number of components that would be rendered inoperable by interruption of system flow. ..

c. The method.of testing proposed by the licensee will yield a quantitative measure of system performance similar to that specified in existing testing requirements.

d. Independent existing surveillance testing requirements As such,provide the for a frequent demonstration of system perfonnance.

capability exists to quickly detect evidence of system degradation /

deterioration.

BASIS UPON WHICH RELIEF CAN BE GRANTED 10CFR50.55(a)(g)(6)(1)providesthattheCommissionwillevaluatewhencode It may grant relief requirements for inservice testing are impractical.

from such requirements and impose alternative requirements as it determines is authorized by law and will not endanger life or property or the connon defense or security, giving due consideration to the burden upon the licensee if the code requirement were imposed.

CONCLUSION The staff has concluded that the code requirements for the specified systems are impractical and the granting of the relief 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 requirements were imposed The staff accordingly concludes, pursuant to 10 CFR on the facility 50.55(a)(g)(6) (1), granted.

PRINCIPAL CONTRIBUTOR:

W. G. Guldemand i Dated: JUL 3 01985 3

. -