ML20204C235

Safety Evaluation Supporting Util Request for Relief from Certain Inservice Exam Requirements of 1974 Edition - Summer 1975 ASME Code Section XI Addenda in Rev 5 to Inservice Insp Program

ML20204C235
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	07/21/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20204C232	List: ML20204C228 ML20204C235
References
NUDOCS 8607310082
Download: ML20204C235 (4)

Text

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO OPERATION OF ZION NUCLEAR POWER STATION, UNIT 2 COMMONWEALTH EDIS0N COMPANY DOCKET NO. 50-304 BACKGROUND By letter dated October 15, 1985, Comonwealth Edison Company (the licensee) submitted Revision 5 to the Zion Generating Station Inservice Inspection Frogram for the First Ten Year Interval. The revision consisted of a request for relief from certain inservice examination requirements of the 1974 Edition through Summer 1975 Addenda of Section XI of the ASME Code at Zion Generating Station Unit 2. The first ten-year inspection interval for Zion Unit 2 ended on September 18, 1984. The relief request is for a pressure test which had been determined to be impractical to perform during the first ten-year interval by the licensee. The licensee proposes to complete the subject pressure test by the next Zion Unit 2 refueling outage. This report provides an evaluation of the licensee's request, supporting information, and alterriotive examination or test, as well as the staff's basis for granting or denying the request pursuant to 10 CFR 50.55a(g). The relief request is evaluated below.

Evaluation of Relief Request Class 3 Hydrostatic Pressure Test of Auxiliary Feedwater System Code Requirements The pressure retaining components within the Class 3 boundary are subject to the hydrostatic test requirements of IWD-5000 each inspection interval.

Code Relief Request and Licensee Proposed Alternative Examination Relief is requested to defer the system hydrostatic pressure test on a portion of the auxiliary feedwater system from the auxiliary feedwater pumps (2A, 2B, and 2C) to 2MOV-FW0050, 51, 52, 53, 54, 55, 56, 57 until the next Unit 2 refueling outage. This is currently scheduled for the Winter of 1986/87.

8607310082 860721 PDR ADOCK 05000304 G PDR

g Licensee Basis for Relief Zion's original design for the auxiliary feedwater system had air operated valves (A0V) for controlling the auxiliary feedwater flow. Due to safety concerns, Zion disconnected the air lines to these A0Vs, failing open the valves, and used the motor operated valves (MOV) downstream of the A0Vs to throttle and control the auxiliary feedwater flow. Because these MOVs were not specifically designed for throttling, after many years the valve seats eroded. This was confirmed during periodic operation of the pumps when flow gauges indicated flow past the MOVs even though the valves were closed. The valves' locations did not permit easy repair, but Zion did disassemble a few valves and found the seat area eroded beyond repair. The Station initiated an auxiliary feedwater system modification in Octobar 1983 so the MOVs would be more accessible for maintenance and have throttling capabilities. The modification requires an extensive outage due to the time frame required with the auxiliary feedwater system out of service; it is, therefore, scheduled for installation during a refueling outage.

Zion must delay the hydrostatic test for the auxiliary feedwater discharge piping until the new MOVs are installed because the existing MOVs cannot hold the test pressure. The delivery of the new valves was delayed due to unexpected manufacturing difficulties and revisions to the procedural control of the valves' manufacture.

While seven of the eight valves have been delivered at the time Revision 5 was filed in October 1981, the modification could no longer be performed without extending the current outage. The eighth valve is being remanufactured due to an inadequate casting. Zion will hydrostatically test the discharge piping after the new MOVs are installed. The A0Vs cannot be used as a pressure boundary since they have not been used in ten years and some of their components have been removed from the valves making them inoperable.

This matter has received station On-Site and Off-Site reviews. All other

.- required hydrostatic tests are expected to be completed within the required l

time frame. Based on the above, it has been determined that deferral of the auxiliary feedwater system hydrostatic test will have no significant effect upon the probability of consequences of a accident or upon the health and safety of the public.

Staff Evaluation and Conclusions The eroded seats of the M0Vs used to isolate portions of the auxiliary I feedwater system prevent the licensee from performing the Code required hydrostatic test until replacement valves have been installed. The licensee has requested to delay the test until the next refueling outage, which is beyond the Code-required inspection interval.

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n;mrestatic tests performed on other portions of the system should provide

....e ;ndication of the general condition of that portion for which the da+arrad test has been requested. A similar request for Zion Unit I has been nrantad by the staff.

Based on the staff's evaluation and the licensee's discussion above, Code reauirements are impractical. It is further concluded that the alternative examination discussed above will provide necessary added assurance of the auxiliary feedwater system's structural reliability. Therefore, the relief may be granted as requested.

Principal Contributor:

Samson 5. Lee b

o July 21, 1986

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. DISTRIBUTION

'. .:. t No. 50-304 Docket File OELD NRC PDR E. Jordan Local PDR B. Grines Mr. D. L. Farrar PD#3 Rdg. J. Partlow Director of Nuclear Licensing H. Denton/D. Eisenhut N. Thompson Commonwealth Edison Company T. Novak- T.Barnhart(4)

Post Office Box 767 ACRS (10)

Chicago, Illinois 60690 ORAS OPA C. Vogan SECY

Dear Mr. Farrar:

J. Norris LFMB

SUBJECT:

ZION NUCLEAR POWER STATION UNIT 2 - RELIEF FROM FIRST TEN-YEAR INSERVICE INSPECTION AND TESTING REQUIREMENTS By letter dated October 15, 1985, the Commonwealth Edison Company (CECO) submitted Revision 5 to the Inservice Inspection Program for Zion Unit 2 and the first ten-year interval. The revision consisted of a request for relief from certain inservice examination requirements of the 1974 Edition through Sumer 1975 Addenda of Section XI of the ASME Code.

We have reviewed this submittal and our review has detennined 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 comon 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 on the facility. Detailed technical assessment is contained in the enclosed Safety Evaluation. Based on our conclusion, pursuant to 10 CFR 50.55a(g)(6)(1), we grant the relief.

Sincerely, Steven A. Varga, Project Director PWR Project Directorate #3

.- Division of PWR Licensing-A

Enclosure:

As stated cc: See next page

• SEE PREVIOUS CONCURRENCE PD#3 PD#3 OELD* 3 CVogan* JNorris* 1 6/20/86 6/27/86 7/03/86 g6

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