ML19308A910
| ML19308A910 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/12/1976 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19308A907 | List: |
| References | |
| NUDOCS 7912120689 | |
| Download: ML19308A910 (3) | |
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NOV12 187 6 CONTAINMENT AIRLOCKS Appendix J to 10 CFR 50 requires that reactor containment airlocks be leak tested at the peak calculated accident pressure (P2) at six -
month intervals. Further, should the air locks be opened during such intervals, the airlocks will be leak tested af ter each opening. Appendix J calls out these specific requirements for airlocks,because they repre-sent a potentially large leakage path that is more subject to human error than other isolation barriers.
The objectives of the airlock leak testing requirements are (1) that the six month test will provide an integrated leakage rate for the entire airlock assembly, including electrical and mechanical penetrations, the airlocks cylinder, hinge assemblies, welded connections, and other potential leakage paths; and (2) that the "after each ope + 3" test will provide a means of assuring that the door seals have :c-. been damaged or seated improperly "uring airlock use.
For those operating facilities that were designed and constructed prior to the issuance of Appendix J, consideration has been given to the alternatives to the specific testing requirements which will meet the provisions of Appendiy. J.
Listed below are a number of guidelines which may be useful wher. considering or revising current air?.ock leak testing programs.
79121206k
NOV 12 1978 i
- l 1.
At six month intervals, the entire airlock assembly shall be leak tested at the peak pressure, Pa.
If the test pressure will lif t the inner airlock door off its seat, strongbacks or other mechancial devices should be used so that meaningful test results can be obtained at Pa.
2.
Should the airlock be opened during the interval between the six month tests, the airlock door seals shall be leak tested I
within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of every first of a series of openings. This relaxation in the "af ter each opening" test requirement of Appendix J recognizes that a significant amount of time is -
required to conduct these intermediate tests in relation to the frequency of use of the airlock. These tests would be conducted whenever containment integrity is required.
3.
For those plants which require the use of.strengbackt or clamps to leak test the door seals at a pressure Pa, a lower pressure (e.g., manufacturer's recommended pressure, which wculd not require the use of such clamping devices) should,be used to conduct the intermediate tests. The results of lea'kage tests at the lower pressure shall be conservatively extrapolated to a Ieakage rate at the accident pressure Pa to determine acceptability.
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I L 2 576 3
4.
In lieu of the intemediate tests,an acceptable alternative would be the use of a continuous monitoring system. As in the case of reduced pressure intermediate tests,it must be demonstrated that the leakage rate using a continuous pressurized monitoring system is sufficiently sensitive, and can.and will be conservatively extrapolated to the leakage rate that would be experienced under accident conditions (i.e., at a pressure of Pa).
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