ML20137H553
| ML20137H553 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 01/10/1986 |
| From: | Miraglia F Office of Nuclear Reactor Regulation |
| To: | OMAHA PUBLIC POWER DISTRICT |
| Shared Package | |
| ML20137H541 | List: |
| References | |
| TAC-8910, NUDOCS 8601210567 | |
| Download: ML20137H553 (5) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMISSION In the Matter of OMAHA PUBLIC POWER DISTRICT Docket No. 50-285 (Fort Calhoun Station, Unit No. 1
)
EXEMPTION I.
Omaha Public Power District (the licensee) is the holder of Facility Operating License No. DPR-40 that authorizes operation of the Fort Calhoun Station, Unit No. 1 (the facility) at a steady state reactor power level not in excess of 1500 megawatts thermal. The facility is a pressurized water reactor (PWR) located at the licensee's site in Washington County, Nebraska. The license provides, among other things, that the facility is subject to all rules, regulations and orders of the Commission now or hereafter in effe-t.
II.
10 CFR 50.54(o) states that primary reactor containments shall be subject to the requirements set forth in Appendix J to this part. Appendix J to 10 CFR Part 50, " Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors," sets forth the detailed requirements for containment leakage testing. These test requirements provide for preoperational and periodic verification by tests of the leak-tight integrity of the primary reactor containment and systems and components which penetrate containment of water-cooled power reactors, and establish the acceptance criteria for such tests.
Section III of Appendix J addresses the specific leakage testing requirements.
B601210567 860110 DR ADOCK O g5
III.
Exemption requests were submitted by the licensee by letter dated January 26, 1983.
IV.
Personnel A'ir Lock Leakage Testing The licensee's proposed leak testing of the containment personnel air lock (PAL) is in compliance with the requirements of Appendix J to 10 CFR Part 50, with one exception. The licensee has requested an exemption from paragraph III.D.2(b)(ii) of Appendix J, which states:
Air locks 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.
Whenever the plant is in cold shutdown, containment integrity is not required. However, if an air lock is opened during cold shutdown, paragraph III.D.2(b)(ii) requires that an overall air. lock leakage test at not less than Pa be conducted prior to plant heatup and startup. The existing PAL doors are so designed that a full pressure, i.e., Pa (60 psig), test can only be perfonned after strong backs (structural bracing) have been installed on the inner door. Strong backs are needed since the pressure exerted on the inner door during the test is in a direction opposite to that of the accident pressure direction. The strong backs are extremely difficult to install and the outer door must be opened to remove the strong backs. As a result, about 18-24 hours are recuirad to complete a full pressure test of an air lock.
9 Alternatively, the licensee proposes to leak test the door seals at 5 psig prior to returning to a plant operating condition requiring containment integrity, and conduct a full pressure test on the PAL assembly within 2 weeks. The licensee contends this proposal will provide adequate assurance of air lock integrity without imposing undue delays on return to power operations.
If the periodic 6-month test of paragraph III.D.2(b)(1) and the test i
required by paragraph III.D.2(b)(iii) are current, there should be no reason to expect an air lock to leak excessively just because it has been opened during cold shutdown or refueling.
Containment integrity, which is required during hot shutdown, hot standby,
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startup, and power operations, will not be violated when the full pressure test is conducted during these modes. One of the requirements for containment integrity is for at least one door in the personnel air lock to be properly closed and sealed. Both doors open inward toward containment. The outer door will be opened prior to the test to permit the strong backs to be placed on the inner door. The closed inner door keeps the integrity of the containment.
The outer door is then closed and the test is performed. Since strong backs are on the inner door, the integrity of the containment is not violated during the test. Once the test is completed, the outer door is opened, the strong backs on the inner door are removed, and the outer door is subsequently closed.
Once this has been completed, the inner door still maintains containment integrity.
Accordingly, the staff concludes that the licensee's proposed approach, consisting of delaying by up to 2 weeks the full pressure (Pa) test required by paragraph III.D.2(b)(ii) and performing a reduced pressure (5 psig) door seal test prior to achieving a condition requiring containment integrity, is i
acceptable.
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l Therefore, an exemption from paragraph ~ III.D.2(b)(ii) of Appendix J to 10 CFR Part 50 is granted.
Type C Testing of Penetration M-3 Isolation Valve The licensee has requested an exemption from the requirements of Appendix J in regard to perfonning Type C leakage tests on the isolation valve in the Charging Pump Discharge Line (penetration M-3).
The justification for not testing this valve is that the pressure (2100 psig) seen by the valve in the direction of flow toward containment is greater than the maximum containment accident pressure (60 psig). All of the charging pumps remain operational or are automatically started and the subject isolation valve remains open upon receipt of a Safety Injection Actuation Signal (SIAS). Thus, the charging pump flow provides a seal barrier against escape of the containment atmosphere. Maintaining this barrier during a loss of coolant accident is assured since, upon receipt of a SIAS, the charging pumps are automatically aligned to the boric acid storage tanks. The volume held by these tanks provides a source of supply to the pumps for approximately 80 minutes and, as demonstrated in the facility's Updated Safety Analysis Report, Section 14.16, the containment pressure would be reduced back to near atmospheric levels (approximately 2 psig) within 50 minutes. Even after the tanks are empty, there will exist a 14-ft water head on the suction side of the charging pumps. This head of water will exert a pressure of approximately 6 psig to provide a seal against air leakage for the remainder of the accident.
The staff finds that an exemption from the Type C testing requirements i
of Appendix J is not needed for the containment isolation valve associated with penetration M-3, since the valve is not included in the valve categories of paragraph II.H of Appendix J, which are required to be Type C tested.
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Furthermore, the staff has detemined that penetration M-3 does not constitute a potential containment atmospheric leak path, for the reasons stated above. Therefore, the licensee may exclude the subject valve from the Type C test program.
V.
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12(a), the exemption is authorized by law and will not endanger life or property or the common defense and security and are otherwise in the public interest and hereby grants an exemption from the requirements of Section III of Appendix J to 10 CFR Part 50 to the extent discussed in Section IV above.
Pursuant to 10 CFR 51.32, the Commission has determined that the issuance of the Exemption will have no significant impact on the environment.
(50 FR 33434).
This exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMMISSION Frank J irag i Director Division of PWR Licensing-B Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland this 10th day of January,1986.
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