ML20235N603

Safety Evaluation Approving Alternate Method for Complying w/10CFR50.55a for Main Steam Positive Leakage Control Sys Valve

ML20235N603
Person / Time
Site:	River Bend
Issue date:	02/21/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20235N594	List: ML20235N591 ML20235N603
References
NUDOCS 8903010302
Download: ML20235N603 (2)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ON AN ALTERNATIVE METHOD OF COMPLYING WITH 10 CFR 50.55a GULF STATES UTILITIES COMPANY RIVER BEND STATION. UNIT 1 DOCKET NO. 50-458 INTRODUCTION By letter dated October 6, 1986, the Gulf States Utilities Company (GSU) submitted a request for relief from a requirement of Section III of the ASME Boiler and Pressure Yessel Code (Code) for its River Bend Station Unit 1. A valve in the Main Steam Positive Leakage Control System contains a disk which does not meet ASME Section III Code requirements. In order to justify such a reouest, the regulation 10 CFR 50.55a(a)(3) requires the licensee to demonstrate that (i) the proposed alternatives provide an acceptable level of quality and safety or (ii) compliance would result in hardship or unusual difficulties without a compensating increase in the level of quality and safety.

DISCUSSION The valve, 1821*M0VF0980, is a dual disk, ASME Class III Pressure Seal, 24" Gate Valve, manufactured by Velan Valve Corporation. Following a LOCA, a positive pressure is maintained in the volume between the disks in the main steam line to prevent leaks from the containment. The valve was originally installed in'accordance with applicable Code requirements. The disk material used in the subsequent replacement of the original valve disk does not meet the ASME Section III requirements for Authorized Nuclear Inspector (ANI)/ Authorized Nuclear Inservice Inspector (ANII) involvement. In order to assure that the replacement disk-is acceptable, GSU reviewed the manufacturer's quality assurance program and verified that the disk was fabricated, inspected, examined, and

-tested in accordance with procurement document requirements. The Velan Valve Corporation, in a letter dated September 26, 1986, also submitted to the licensee documentation which certified that the part was manufactured, tested, and inspected in accordance with Velan's ASME Quality Assurance Manual except for ANI involvement.

The licensee stated that Velan Yalve Corporation verified that the disk in question was produced in full compliance to Code requirements except for the third party, (ANI)/(ANII) review. The additional bases to support the argurent that the alternative method of compliance meets the requirement of 10 CFR 50.55a(a)(3) are as follows:

1. The GSU review of the Velan's work traveler showed that examinations required by ASME Section III, NC-5273, were performed by appropriate Quality control personnel.

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2. A detailed review by the licensee and the ANI/ANII was performed on the Non-destructive Examination (NDE) procedures and the Non-destructive Testing (NDT) personnel certification. It indicated compliance with the applicable ASME Codes.

3. Procedures and cer:1fication relative to welding were provided by the GSU and the GSU's ANI/ANII. The review showed that the welders and the welding procedures were qualified in accordance with ASME Sections III, IX, and XI.

4. A review of the Certified Material Test Reports and the Certificates of Compliance by the GSU and the GSU's ANI/ANII indicated compliance with Ccde requirements.

Further, in order to provide reasonable assurance of operational readiness, the technical specifications and the inservice testing program require periodic func-tional tests, including leak testing and full stroke exercising.

If this relief is not granted, the valve would have to be declared inoperable by the licensee and the valve would have to be modified so that an installed disk would have the ANI/ANII approval in accordance with ASME Section III requirements.

CONCLUSION In the evaluation of the disk for the valve, 1821*MOVF098C, the licensee stated that all procedures, examinations, and certification which provide the bases for ANI's review are available and in compliance with applicable ASME Code requirements.

The available documentation indicates that the valve disk in question was produced in an identical manner to one in complete compliance. Further, to provide reasonable assurance of operational readiness, this valve is required to be periodically tested in the technical specifications and in the inservice testing program. Compliance, with respect to ANI's review in this case, would result in hardship or unusual difficulties without a compensating increase in the level of quality and safety.

The staff concludes, therefore, that the proposed alternative is acceptable and '

in accordance with 10 CFR 50.55a(a)(3).

Principal Contributor: X. Dempsey Dated: February 21, 1989 l

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