ML20137H594
| ML20137H594 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 01/10/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20137H541 | List: |
| References | |
| NUDOCS 8601210576 | |
| Download: ML20137H594 (3) | |
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UNITED STATES g
NUCLEAR REGULATORY COMMISSION WASHWGTON, D. C. 20666 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATtl) TO EXEMPIIONS FROM 10 CPR PART 50, APPtNUIX J FACILITY OPERATING LICENSE NO. DPR-40 DMAHA PUdLIC POWER DI51RICT FORT CALHOUN STATION, UNIT NO. 1 DOCKET NO. 50-285 j
1.0 Introduction i
By letter dated January 26, 1983, the Omaha Public Power District (the licensee) requested approval for exemptions from the technical i
requirements of Section III of Appendix J to 10 CFR Part 50 for the Fort l
Calhoun Station, Unit No. 1.
The January 26, 1983 letter also updated l
proposed Appendix J related technical specification changes which were I
originally proposed by amendment application dated March 30, 1977. By letter dated November 27, 1985, the licensee further updated the proposed Appendix J related technical specification changes. This i
safety evaluation addresses the licensee's exemption requests. An j
exemption from certain requirements for air lock testing is proposed.
An exemption from Type C testing of penetration M-3 isolation valves is also proposed. Our review of the licensee's proposed technical specification chances is continuing and the changes will be the subiect of a separate evaluation.
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2.0 Evaluation 2.1 Personnel Air 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 i
the end of such periods at not less than Pa.
Whenever the plant is in cold shutdown, containment integrity is not-l 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 i
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 performed after strong backs (structural bracing) have been installed on the inner door. Strong backs are needed since the presr re 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 required to complete a full pressure test of an air lock.
8601210576 960110 i
PDR ADOCK 05000285 P
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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)(i) and the test 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, 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 l
(5 psig) door seal test prior to achieving a condition requiring containment integrity, is acceptable.
Therefore, an exemption from paragraph III.D 2(b)(ii) of Appendix J to 10 CFR Part 50 is acceptable.
l 2.2 Type C Testing of Penetration M-3 Isolation Valve The licensee has requested an exemption from the requirements of Appendix J l
in regard to performing 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 t
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 l
pump flow provides a seal barrier against escape of the containment l
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, i'_.
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 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 requirad to be Type C tested.
Furthermore, the staff has determined 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.
3.0 Sunnary Based upon the staff's evaluation, the following exemption should be granted:
Personnel Air Lock Leakage Testing (Paragraph III.D.2(b)(ii) of Appendix J)
The exemption request concerning type C testing of penetration M-3 isolation valve is not needed.
Date:
January 10, 1986 Principal Contributors:
J. Pulsipher l
E. Tourigny l
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