ML20248D454

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Exemption from Requirements of 10CFR50,App J,Section III.A.6(b) Re Containment Integrated Leak Rate Test Interval & 6-month Extension of Test Interval for Valves & Drywell Head & Access Hatch
ML20248D454
Person / Time
Site: Pilgrim
Issue date: 09/27/1989
From: Varga S
Office of Nuclear Reactor Regulation
To:
BOSTON EDISON CO.
Shared Package
ML20248D458 List:
References
NUDOCS 8910040269
Download: ML20248D454 (9)


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UNITED STATES OF AMERICA k

NUCLEAR REGULATORY COMMISSION a.

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In the Hatter of

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BOSTON EDISON' COMPANY

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' Docket No. 50-293

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(Pilgrim Nuclear Power Station)

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EXEMPTION I.

The Boston Edison Company (BEco), the licensee, is the holder of Operating License No. DPR-35 which authorizes operation of the Filgrim Nuclear Power Station (PNPs). -The license provides, among other things, that:the PNPS' is-subject to all rules, regulations, and Orders of the Commission now or here-after in effect.

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The plant-is a boiling water reactor at the ifcensee's site located in

- Plymouth County, Massachusetts.

II.

Section III.D.(a) of Appendix J to 10 CFR Part 50 requires that a Type A Primary Containment Integrated Leak Rate Test (PCILRT) be performed at approxi-mately equal intervals during each 10-year service period. SectionIII.A6(a) of Appendix J to 10 CFR Part 50 requires that if any periodic Type A test fails

- to meet the applicable NRC acceptance criteria, a review of the test schedule be performed and approved by the Commission.Section III.A.6(b) of Appendix J also requires that if two consecutive p'!:riodic Type A tests fail to meet the applicable NRC acceptance criteria, a Type A test shall be performed at each l

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. i subsequent refueling outage or approximately every 18 months, whichever comes first, until two-consecutive Type A tests meet the acceptance criteria given in Section III.A.5(b).

Section III.D.2.(a) of Appendix J to 10 CFR Part 50 requires that Type'B.

Local Leak Rate Tests (LLRTs), except tests for air locks,- shall be performed during reactor shutdowns for refueling, or other convenient interval, but'in no case at intervals greater than two years.

Section III.D.3 of Appendix J to 10 CFR Part 50 requires that Type C LLRTs shall be performed during each reactor shutdown for refueling, but in no case at intervals greater than two years, for containment isolation valves.

III.

The PCILRTs performed during the 1982, 1983, and 1987 refueling outages of the PNPS were deemed failures in the "as-found" condition due to penalties as the result of leakage from the pathways of the Type B and C LLRTs. Accord-ingly, the licensee would be required to perform a PCILRT during the surveil-lance outage scheduled for October 1989. As an altern9tive to performing the required Type A test, the licensee has, submitted a Corrective Action Plan to eliminate excessive local leakage in accordance with the guidance provided in NRC Information Notice 85-71, " Containment Integrated Leak Rate Tests," dated August 22, 1985. The Corrective Action Plan is in lieu of the increased test frequency required by Section III.A.6(b) of Appendix J to 10 CFR Part 50.

l-Therefore, an exemption from this requirement is needed.

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d The Corrective Action Plan includes a LLRT Failure Analysis Team to investigate LLRT failures, determine root causes, and recommend corrective actions..The plan also includes a trending program, test method improvements and augmented testing. - Analysis of failures during the last refueling outage (RFO-7) and corrective actions for all LLRT failures were implemented resulting in the "as-left" PCILRT at PNPS in December of 1987, being the lowest leakage in the plant's history. As part of the augmented testing portion of the plan, two additional LLRTs have been performed subsequent to the. corrective actions implemented in December of 1987. These ta ts verified that the root cause analyses and corrective actions were successful. LLRTs will be performed during the upcoming maintenance outage in the Spring of 1990, with the exception of specific penetrations which will be discussed later. The licensee further indicates that LLRTs will be conducted during any planned outage of greater than 30 days at PNPS. The penetrations selected for the tests will be based on the results of the trending portion of the Corrective Action Plan. This Plan will result in the completion of five full sets of LLRTs between June 1987 and June 1991; this exceeds Appendix J requirements.

In addition, the licensee previously initiated a Valve Betterment Program which has resulted in the replacement of 17 valves and modifications to 12 other valves which were identified as having excessive leakage.

The Corrective Action Plan includes long term corrective actions in addition to augmented testing and trending. These actions include the opening and inspection of at least one feedwater check valve and ifne loading or

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replacement of packing in the main drain outboard isolation valves during each refueling outage; and procurement of spare parts, such as seats, bronze bushings and associated hardware for the torus main exhaust valves.

It should be noted,

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. that the major portion of the leakage (about 83%) as the result of the LLRTs performed in December 1987, was due to the feedwater check valves. The short term replacement of problem components in the valves and the long-term effort previously discussed, has resulted in successful testing to date.

The licensee's Corrective Action Plan, Valve Betterment Program and recent results of the LLRTs will provide an equivalent level of protection as that provided by the more frequent testing requirement by Section III.A.6(b) for Type A PCILRT. The staff concludes that a one-time extension until RFO-8 and a return to the normal Type A test schedule of Section III.D of Appendix d 'to 10 CFR Part 50 is justified. This conclusion is based on the next Type A test, which will be performed during RF0-8, meeting the established NRC acceptance criteria.

If the criteria is not met, the licensee shall revert to the more frequent testing requirement of Section III.A.6(b).

A one-time schedule exemption from the test interval requirement of Section III.D 2(a) of Appendix J to 10 CFR Part 50 for the drywell head and the drywell head access hatch is needed due to the extent of the work required to be performed and resultant worker exposure to radiation, which would result, if the tests were required to be performed during the upcoming outage in October

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1989. Nine shield blocks above the drywell must be removed. These are normally removed only during refueling outages, such as the upcoming RFO-8, to allow removal of the reactor head for fuel unloading and loading.

The drywell head and access hatch have exhibited minimum leakage which is only detectable on the most sensitive scale of the measuring instrumentation for al.1 previous LLRTs. The request provides only temporary relief for approximately six months from the maximum two-year test interval required by Section III.D.2(a) of Appendix J to 10 CFR Part 50.

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> The staff concludes that the accelerated LLRTs, previous test history, the ' extent of work required, resulting worker exposure to radiation and the l

short interval of the extension, support the requested one-time schedule extension of six months.

The one-time schedule exemption from the requirement of Section III.D.3-of Appendix J to 10 CFR Part 50 is requested for the Shutdown Cooling Suction Isolation' Valves (M0-1001-47 and MO-1001-50) and Reactor Building Closed Cooling Water (RBCCW) Isolation Valves (M0-4002 and Check Valve 30-CK-432).

The schedule extension for the Shutdown Cooling Suction Isolation valves is needed to defer the leak rate testing until the next scheduled refueling outage. The shutdown cooling system is the only normal means of removing decay heat from the reactor vessel during short outages, such as the upcoming October 1989, surveillance outage. The valves have been tested four times since May 1987. Only one failure occurred in M0-1001-50. As a result, the valve was refurbished and has successfully passed three subsequent LLRTs.

The schedule extension for the RBCCW system isolation valves is needed because the testing would impact components cooled by the RBCCW system during the upcoming short outage. The RBCCW system is a closed-water system and does not provide a direct leakage flow path from the drywell to the secondary containment.

In addition, staging to provide access must be built and removed resulting in considerable exposure of workers to radiation. The water in the system is also required to be drained and treated which will result in an increase in the production of radioactive waste.

The previous LLRTs performed on these valves, which include three since 1987, have demonstrated minimal leakage, similar to that discussed above, related to the drywell head and access hatch.

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~In relation to the-shutdown cooling.. suction isolation valves and the RBCCW valves,: the staff concludes based on the accelerated LLRTs, the previous test history, the required system functions that would be needed during the upcoming October outage, added worker exposure, increased production of

- radioactive waste, and the.short interval of the extension, that the requested -

. one-time schedule extension of six months is acceptable.

The staff's Safety. Evaluation dated September 27, 1989, provides additional details'and bases supporting the requested exemptions.

IV.

As discussed above, the underlying purpose of the requirements of Section III.A.6(b) of Appendix J to 10 CFR Part 50 is to ensure the integrity of the primary containment.and its penetrations. The underlying purpose is achieved and served by the licensee's Corrective Action Plan, Valve Betterment Program and'recent good test results of the LLRTs. Thys, an equivalent level of protection is provided.

Therefore, the Commission's staff finds that.there are special circum-I stances in this case which satisfy the standards of 10 CFR Part 50.12(a)(2)(fi).

L Also as discussed above, the underlying purpose of the requirements of III.D.2(a) and III.D.3 of Appendix J to 10 CFR Part 50 are to detect local leaks and measure leakage across primary reactor penetrations and containment l-isolation valves at intervals of no greater than two years. The licensee has made a good faith effort to comply with the regulations by performing an increased number of LLRTs on containment penetrations and valves, including the ones discussed above.

In addition, the previous test history, corrective actions,

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'l 7-and need for the Shutdown Cooling System and RBCCW system during the October outage, support the requested one-time schedule extension of six months. Thus, the exemption which is only to provide temporary relief, and in that the licensee-has made a good faith effort to comply with the regulations; thus, again an equivalent level of protection is provided.

i Therefore, the Commission's staff finds that there are special circumstances, in these-instances, which satisfy the standards of 10 CFR Part 50.12(a)(2)v.

V.

Based upon the above evaluation, the staff considers the licensee's alternate test schedul'e to be equivalent to that achieved by conformance to Appendix J to 10 CFR Part 50. Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a)(1), this exemption is authorized by law, will not

_ present an undue risk to the public health and safety, and is consistent with the common defense and security. The Commission has further determined that special circumstances, as set'forth in 10 CFR 50.12(a)(2)(ii) are present, justifying the exemption; namely, that application of the regulation in this particular circumstance is not necessary to achieve the purpose of the rule.

Accordingly, the Commission hereby grants an exemption to Section III.A.6(b) of Appendix J to la CFR Part 50 to allow the licensee to perform the next Type A test during RF0-8 and to resume the Type A retest schedule of Section III.D.1(a) for the PNPS.

This exemption does not apply if the next Type A test is deemed a failure based on the NRC acceptance criteria. Such a i

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failure would require the-licensee to comply with the retest schedule of Section III.A.6(b) until two consecutive Type A tests meet the NRC acceptance criteria.

i The Commission has further determined that the special circumstances, as set forth in 10 CFR 50.12(a)(2)(v) are present, justifying the one-time schedule -

extension of approximately six months, in that the licensee has made a good faith effort to comply with the regulations.

Accordingly, the Commission hereby grants a one-time exemption to the schedule requirements of III.D.2(a) and III.D.3 for the required Type B and C LLRTs as follows:

III.D.2.(a) (Type B Tests) - Drywell Head

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Drywell Head Access Hatch III.D.3l(Type C Tests)

Isolation Valve M0-1001-47 Isolation Valve M0-1001-50 Isolation Valve M0-4002 Check Valve 30-CK-432 The LLRTs on the penetrations and valves identified above will be performed during RFO-8.

Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this exemption will not have a significant effect on the quality of the human environment (54 FR 39236).

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L This exemption is effective upon issuance.

'FOR THE. NUCLEAR REGULATORY COMMISSION f

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  • reg c r DivisionofReactorPQcts-I/II Office of Nuclear Reacto' Regulation

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Dated at Rockville, Maryland this 27thday of September,1989.

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