ML13316B273
| ML13316B273 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/25/1989 |
| From: | Holahan G Office of Nuclear Reactor Regulation |
| To: | Southern California Edison Co |
| Shared Package | |
| ML13316B272 | List: |
| References | |
| NUDOCS 8902020400 | |
| Download: ML13316B273 (5) | |
Text
7590-01 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
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Docket No. 50-206 SOUTHERN CALIFORNIA EDISON COMPANY
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License No. DPR-13 SAN DIEGO GAS AND ELECTRIC COMPANY
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San Onofre Nuclear Generating Station, )
Unit No. 1
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EXEMPTION I.
Southern California Edison Company and San Diego Gas and Electric Company (the licensees) are the holders of Provisional Operating License No. DPR-13 which authorizes the licensees to operate San Onofre Nuclear Generating Station, Unit No. 1, at power levels up to 1347 megawatts thermal (rated power). The facility is a pressurized water reactor located on the licensees' site in San Diego County, California. The license is subject to all applicable provisions of the rules, regulations and orders of the Nuclear Regulatory Commission.
II.
Paragraph III.D.2(b)(ii) of Appendix J to 10 CFR 50, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors", states that air locks that have been opened during periods when containment integrity is not required by the plant's technical specifications shall be tested at the end of such periods at not less than Pa (calculated peak containment pressure for design-basis events). The licensees have requested a partial exemption from this requirement. The licensees propose to conduct the above test only when maintenance has been conducted that could affect the sealing capability of the c8902020400.390125 PDR ADOCK 0500006.
P
-2 air lock door seals. Otherwise, the air lock would be tested at least every six months at Pa (49.4 psig) and also within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after each closing at 10 psig test pressure.
III.
Whenever the plant is in cold shutdown (mode 5) or refueling (mode 6),
containment integrity is not required. However, if an air lock is opened during modes 5 and 6, Paragraph III.D.2(b)(ii) of Appendix J requires that an overall air lock leakage test at not less than Pa be conducted before plant heatup and startup (i.e., entering mode 4).
The existing air lock doors are so designed that a full-pressure (i.e., Pa (49.4 psig)) test of an entire air lock can only be performed after strongbacks (structural bracing) have been installed on the inner door. Strongbacks are needed because the pressure exerted on the inner door during the test is in a direction opposite to that of the accident pressure direction. Installing strongbacks, performing the test, and removing the strongbacks requires several hours, during which access through the air lock is prohibited.
When no maintenance has been performed on the air lock that could effect its sealing capability, and the air lock doors have been closed in accordance with the licensees' procedure, and the periodic 6-month test at Pa required by Paragraph III.D.2(b)(i) of Appendix J 'has been performed on schedule, there is no reason to expect the air lock to leak excessively just because it has been opened in a shutdown or refueling mode. Performing the door seal leak test (10 psig) of Paragraph III.D.2(b)(iii) of Appendix J is sufficient, in this case, to demonstrate the continuing integrity of the air lock.
-3 Accordingly, the staff concludes that the licensees' proposed approach of substituting the seal leakage test of Paragraph.III.D.2(b)(iii) for the full-pressure test of Paragraph III.D.2(b)(ii) of Appendix J is acceptable when no maintenance that could affect sealing capability has been performed on an air lock. Whenever maintenance that could affect sealing capability has been performed on an air lock, the requirements of Paragraph III.D.2(b)(ii) of Appendix J must still be met by the licensees.
The purpose of this provision of Appendix J to 10 CFR 50 is to ensure that containment leaktight integrity of air lock penetrations is verified after closure so as to maintain containment leakage within the limits specified in the facility Technical Specifications. The proposed alternative test method of air lock door seal leakage is sufficient to achieve this underlying purpose in that it provides adequate assurance of continued leaktight integrity of the air lock. Because of this, the staff has previously granted this same exemption.
to other plants and intends to revise Appendix J to alleviate the need for further similar exemptions. Consequently, the special circumstances described by 10 CFR 50.12(a)(2)(ii) exist in that application of the regulation in these particular circumstances is not necessary to achieve the underlying purpose of the rule since the licensee has proposed an acceptable alternative test method that accomplishes the intent of the regulation.
-4 Therefore, a partial exemption from this requirement (10 CFR 50, Appendix J, Paragraph III.D.2(b)(ii)) is justified and acceptable, and the licensees' proposal to adopt Surveillance Requirement 4.6.1.3 of Revision 4 of NUREG-0452, "Standard Technical Specifications for Westinghouse Pressurized Water Reactors,"
is acceptable (NUREG-0452, Rev. 4, was written to accommodate this type of exemption). Further, the staff finds that, in accordance with 10 CFR 50.12(a)(2),
the requested exemption represents special circumstances, as discussed above and is consistent with the intent of Appendix J.
IV.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, 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 further determines that special circumstances, as provided in 10 CFR 50.12(a)(2)(ii) and (iii), are present justifying the exemption.
Therefore, the Commission hereby approves the following exemption to Paragraph III.D.2(b)(ii) to Appendix J to 10 CFR Part 50:
Air locks opened during periods when containment integrity is not required by the Technical Specifications shall be tested at the end of such periods at not less than Pa when maintenance has been performed on the air lock that could affect the air lock sealing capability.
S
-5 It is further determined that the exemption does not authorize a change in effluent types or total amounts nor an increase in power level and will not have a significant effect on the quality of the human environment. In light of this determination and as reflected in the Environmental Assessment and Finding of No Significant Impact prepared pursuant to 10 CFR 51.2 and 51.30 through 51.32, it is concluded the instant action is insignificant from the standpoint of environmental impact and an environmental impact statement need not be prepared.
For further details with respect to this action, see the application for amendment and exemption request dated March 20, 1987, as supplemented July 22, 1988 and the Commission's Environmental Assessment and Finding of No Significant Impact dated January 6, 1989 (54 FR 1258). These are available for public inspection at the Commission's Public Document Room, 2120 L Street, NW, Washington, DC 20555, and at the General Library, University of California, P.O. Box 19557, Irvine, California 92713.
This exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMMISSION Gary M. Holahan, Acting Director Division of Reactor Projects -
- III, IV, V and Special Projects Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 25th day of January, 1989