ML20248E909
| ML20248E909 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/29/1989 |
| From: | Virgilio M Office of Nuclear Reactor Regulation |
| To: | SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| Shared Package | |
| ML20248E879 | List: |
| References | |
| NUDOCS 8904120400 | |
| Download: ML20248E909 (5) | |
Text
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of i
THE SACRAMENTO MUNICIPAL Docket No. 50-312 UTILITY DISTRICT
)
(RanchoSecoNuclearGenerating Station)
)
EXEMPTION 1.
The Sacramento Municipal Utility District (SMUD, the licensee) is the holder of Facility Operating License No. DPR-54 (the license) which authorizes the operation of the Rancho Seco Nuclear Generating Station (Rancho Seco) at a steady-state power level not in excess of 2772 megawatts thermal. The facility consitts of a pressurized water reactor (PWR) located in Sacramento County, California. This license provides, among other things, that it is subject to all rules, regulations and orders of the Commission now or here-after in effect.
11.
Section 50.54(o) of 10 CFR Part 50 requires that primary reactor contain-ments for water cooled power reactors be subject to the requirements of Appendix J to 10 CFR Part 50. Appendix J contains the leakage test requirements, schedules, and acceptance criteria for tests of the leak-tight integrity of the reactor containment building and systems and components which penetrate the 8904120400 890329 PDR ADOCK 05000312 P
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. ct r t r i nr:e r '.
Section III.D of Appendix J requires that local leak rate tests be performed during each reactor shutdown for refueling but in no case at intervals greater than two years.
Rancho Seco was last shut down for refueling in the summer of 1985 and loc 61 leak rate tests were performed at that time.
Following the refueling, the plant remained in colt..atdown through 1986 and 1987 while modifications tc upgrade thc plant were completed.
In anticipation of plant heat-up and restart during the fall of 1987, loce' leal rate tests, that can only be performed while the plant is in cold shutchtn, were again performed in the summer of 1987.
Due to unexpected delays, the plant did not restart until March 1988.
Rancho Seco Technical Specifications require that local leak rate tests t e corf ieted once every 24 months in accordance with 10 CFR Part 50, Appendix J.
Integreted containment leak rate tests are conducted 3 times in 10 years to ensure that following a postulated airborne radioactive release inside contain-ment, leaLace frora the containment will not cause radioactive exposures,t the site boundary to exceed the limits specified in 10 CFR Part 100.
Local leak rate tests of individual containment penetrations (potential leak paths) are perforo.ed as interim checks,f containment integrity.
In the case of Rancho Seco, due to schedule perturbations associated with plant restart following the 27 month shutdown and a subsequent prolonged power ascension program, the synchronism between local leak rate tests and refueling schedules was disturbed.
Since the 1988 restart, the plant has not beeri ir cold shutdown for any extended period and the licensee has been unable to corplete all leek rate tests that require cold shutdown as a prerequisite.
. Betet on the 24 month interval, the next series of leak rate tests are required to be completed in the summer of 1989. The next refueling and cold shutdown is scheduled in the fall of 1989.
Due to the unusually long period between extended cold shutdowns, Rancho Seco can not complete the local leak rate tests within the prescribed interval unless the plant is shut down and cooled to cold shutdcwn.
III.
Ey letter dated December 30, 1988 and supplemented on March 6, 1989, the licensee requested a change to the Rancho Seco Technical Specifications to extend the period between local leak rate tests to a period that would coin-cide with the next scheduled reactor refueling. On February 15, 1989, the licensee requested an exemption from 10 CFR Part 50, Appendix J to complete the regulatory process involved with modifications of local leak rate test requirements.
IV.
From the standpoint of additional risk to the health and safety of the general public, a one-time extension of not more than six months to the normal schedule for performing local leak rate tests is virtually insignificant. The 24 month interval requirement for containment penetrations is intended to be
. V.
I enouch to pre'ent significant deterioratiori from occurring and long enough to permit the LLRTs to be performed 'Juring plant outages.
Leak testing of the penetrations during plant shutdown is preferable because of the lower radiation 2
exposures to plant personnel. Moreover, seme penetrations, because of their intended functions, cannot be tested during power operation. Testing of certain other penttretions during plant operation would cause a degradation in the plant's overall safet) (e.g., the closing of a redundant line in a safety system).
In these situations, the increase in confidence of containment integrity following c successful test fs not significant enough to justify a plant shutdown specifically to perform the LLRTs within the 24 month time period.
A detailed sti safety evaluation of this change is included with the associated Technica?
SptLification amendment. The staff has concluded that a one-time extension of the perioc for loca: leak rate tests, the extension pot to exceed 6 months, will not adversely affect the health and safety of the public and that the requested exemption from the requirements of 10 CFR 50, Appendix J, Section 111 D.2 should be granted.
Accordingly, the Commission has determined tnat pursuant to 10 CFR 50.12(a), the exemption is authorized by law, will not present an undue risk to the public health end safety, ia consistent with the common defense and security, and provides only temporary relief from the applicable regulation and the licensee has made good faith efforts to comply with the regulation.
Therefore, the Commission hereby grants the following exemption:
-5 Exemption is granted from the requirement of 10 CFR 50, Appendix J, Section III D.2, that requires a maximum 24-month interval between local leak tests for components subject to local leak test requirements as delineated in the Rancho Seco Technical Specifi-cations. The exemption is granted on a one-time basis for local leak rate tests that are currently scheduled to be performed in 1989. This exemption will not extend the interval between local leak rate tetts for any individual component by more than 6 months.
Pursuant to 10 CFR 51.32, the Commission has determined that the issuance of this exemption will not have a significant effect on the quality of the human environment (54 FR 12696).
FOR THE NUCLEAR REGULATORY COMMISSION (A-W Martin J.
irgilio,(A) Director Division of Reactor Projects III, IV, Y and Special Projects Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 29th day of March,1989