ML20248E937

Safety Evaluation Supporting Amend 102 to License DPR-54

ML20248E937
Person / Time
Site:	Rancho Seco
Issue date:	03/29/1989
From:	Office of Nuclear Reactor Regulation
To:
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ML20248E879	List: ML20248E877 ML20248E909 ML20248E922 ML20248E937
References
NUDOCS 8904120407
Download: ML20248E937 (3)

Text

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...s SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.102 TO FACILITY OPERATING LICENSE DPR-54 l

RANCHO SECO NUCLEAR GENERATING STATION, UNIT 1

_ DOCKET NO. 50-312

1.0 INTRODUCTION

By letter dated December 30, 1988, the Sacramento Municipal Utility District (SMUD, the licensee) requested an amendment to the Technical Specifications (TS) appended to Facility Operating License No. DPR-54 for Rancho Seco huclear Genera-ting Station. The amendment would permit a one-time extension of the test period for local leakage rate test (LLRT) for certain containment penetrations from March 29, 1989, or later, until the next refueling outage, which is currently scheduled to begin the fall of 1989.

In addition, the test period for the containment penetrations containing piping from the containment emergency sump to the decay heat removal suction valve would change from each refueling interval to once per 24 months.

2.0 BACKGROUND

Rancho Seco was shut down for a refueling outage in the summer of 1985.

This outage lasted much. longer than expected due to unforeseen events; restart did not begin until March 1988.

In anticipation of an earlier restart, LLRTs were successfully completed on the containment penetrations in May and June 1987.

In addition, the present operating cycle (Cycle 7) duration has been lengthened due to an extensive power escalation program and several short outages. Only three containment penetrations that are cue for testing prior to September 1989 have not had LLRTs completed during one of these outages.

3.0 EVALUATION

a. One-Time Extension for Certain LLRTs By letter dated February 15, 1989, from D. R. Kenter, SMUD, to G. W. Knighton, 1

NRC, the licensee requested an exemption from the requirements of 10 CFR E0, Appendix J, so as to extend the two year testing interval for LLRTs

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on certain Rancho Seco containment penetrations. This request for 1

exemption, if granted, would allow the licensee to perform the required LLRTs during the next scheduled refueling outage, which is currently scheduled to begin the fall of 1989.

In the request for amendment, dated December 30, 1988, as supplemented March 6, 1989, the licensee provided, for each containment penetration.,

information on the test results from previous LLRTs.

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• lhe staff has reviewed the information contained in the above referenced letters and has concluded that it would be acceptable to postpone, until the Fall 1989 scheduled refueling outage, the required LLRTs for contain-ment penetrations 14, 30, and 31 (TS 4.4.1.2.1(6) for penetration 14 and TS 4.5.3.2.A.3 for penetrations 30 and 31). Accordingly, an exemption from the requirements of 10 Part CFR 50, Appendix J should be granted for these penetrations until the fall of 1989.

The staff's conclusion that the LLRTs for the three containment penetrat-ions for Rancho Seco can be p::stponed until the Fall 1989 refueling outage without presenting a significant safety concern is cased on the following considerations:

1.

Since the last time these penetrations were tested, May and June 1987, the plant remained slutdown until March 1988 and.there have been several short outages since the flarch 1988 restart.

Plant components, including these penetrations, were not exposed to the normal operating temperature, pressure and radiation conditions durir.g the shutdown and the several short outages. The time interval of 24 months specified in 10 CFR Part 50, Appendix J, for LLRTs was based, in part, on the expected degradation of components exposed to the environment resulting from a full 24 months of normal plant operations. The total exposure time for the containment penetrations to the normal plant operating environment at Rancho Seco will be substantially less than 24 months, including the time period involved in the extension to the Fall 1989 refueling outage.

2.

The favorable results of previous LLRTs performed during past outages was a major factor in the staff's decision.

Each penetration. has a good history of substantially lower than normal leak rates based on the previous LLRTs. These previous test results provic'e a high degree of assurance that an extension in the 24 month test interval requirement will not result in a significant decrease in the integrity of these penetrations.

3.

The 24 month interval requirement for containment penetrations is ir, tended to be often enough to prevent significant deterioration from occurring and long enough to permit the LLRTs to be performed during plant outages.

Leak testing of the penetrations during plant shutdown is preferable because of the lower radiation exposures to plant personnel. Moreover, some penetrations, because of their intended functions, cannot be tested during power operation.

Testing of certain other penetrations during plant operation would cause a degradation in the plant's overall safety (e.g., the closing of a redundant line in a safety system),

in these situutions, the increase in confidence of containment integrity following a successful test is not significant enough to justify a plant shutdown specifically to perform the LLRTs within the 24 month time period, es long as the penetrations are in compliance wi?.h items 1 and 2 above.

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LLfC Interval for Decay Heat Removal Suction Piping Currently TS 4.5.3.2. A part 2 requires the piping from the containment emergency sump to the decay heat removal pump suction isolation valve to be tested as a LLRT under TS 4.4.1.2 during each refueling interval.

Refueling interval is defined in TS 1.9 as no more than 18 months with an option to extend the interval by a maximum of another 25 percent resulting in a maximum interval of 22.5 months.

TS.4.4.1.2, LLRTs, have an interval of not more than 24 months, with no option for extension.

Section III.D.3 of Appendix J to 10 CFR Part 50 states that the maximum interval between tests shall be no more than two years. The licensee proposes to change the TS interval for TS 4.5.3.2.A part 2 to no nore than 24 months, with no option to extend it an additional amount.

This proposal is consistent with the requirement of.10 Part CFR 50, Appendix J, and therefore the staff finds it to be acceptatle.

4.0 CONTACT WITH STATE OFFICIAL The NRC staff has advised the Chief of the Radiological Health Branch, State Department of Health Services, State of California, of the proposed determination of no significant hazards consideration. No comments were received.

5.0 ElP.'IFO WENTAL CONSIDERATION This amendment involves changes in the installation or use of a facility conponer.t located within the restricted area as defined in 10 CFR Part 20.

The staff has determined that the amendment involves no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational. radiation exposure.

The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria foi categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pur.suant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

6.0 CONCLUSION

We have concluded, based on the considerations discussed above, that (1) will not be endangered by operation in the proposed manner, (2) public there is reasonable assurance that the health and safety of the such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to common defense and security or to the health and safety of the public.

Frincipal Contributor:

5. Reynolds Dated: 11 arch 29,1989

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