ML20090E048
| ML20090E048 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 03/04/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20090E054 | List: |
| References | |
| NUDOCS 9203090211 | |
| Download: ML20090E048 (1) | |
Text
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3/4.6 CONTAINMENT SYSTEMS BASES 3/4.6.1 PRIMARY CONTAINMENT 3/4.6.1.1 PRIMARYCONTAINMENTINTEGRiq PRIMARY CONTAINMENT INTEGRITY ensures that the release of radioactive materials from the containment atmosphere will be restricted to those leakage paths and associated leak rates assumed in the accident analyses.
This restrie-tion, in conjunction with the leakage rate limitation, will limit the site boundary radiation doses to within the limits of 10 CFR Part 100 during accident conditions.
3/4.6.1.2 CONTAINMENT LEAKAGE The limitations on containment leakage rates ensure that the total containment leakage volume will not exceed the value assumed in the accident analyses at the peak accident pressure of 11.5 psig, P vatism, the measured overall integrated leakage rate if. As an added conser-further limited to less than or equal to 0.75 L,the containment leakage barriers b tduring performanc possible degradation of e ween leakage tests.
Operating experience with the main steam line isolation valves has indicated that degradation has occasionally occurred in the leak tightness of the valves; therefore the special requirement for testing these valves.
The surveillance testing for measuring leakage rates is consistent with the requirements of Appendix J to 10 CFR 50 with the exception of exemptions granted for testing the airlocks after each opening, and uncoupling the third Type A test of each 10 year service period from the last outage of that period.
3/4.6.1.3 CONTAINMENT AIR LOCKS The limitations on closure and leak rate for the containment air locks are required to meet the restrictions On PRIMARY CONTAINMENT INTEGRITY and the containment leakage rate given in Specifications 3.6.1.1 and 3.6.1.2.
The specification makes allowances for the fact that there may be long periods of time when the air locks will be in a closed and secured position during reactor operation.
Only one closed door in each air lock is required to maintain the integrity of the containment.
Verification that each air lock door inflatable seal system is OPERABLE by the performance of a local leak-detection test for a period of less than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is permissible if it can be demonstrated that the leakage rate can be accurately determined for this shorter period.
(This is in accordance with Sections 6.4 and 7.6 of ANSI N45.4-1972.)
3/4.6.1.4 MSIV LEAKAGE CONTROL SYSTEM Calculated doses resulting from 'the maximum leakage allowance for the main steamline isolation valves in the postulated LOCA situations would be a small fraction of the 10 CFR 100 guidelines, provided the main steam line system from the isolation valves up to and including the turbine condenser remains intact.
Operating experience has indicated that degradation has occasionally occurred in the leak tightness of the MSIV's such that the specified leakage requirements have not always been maintained continuously.
The requirement for-the leakage control system will reduce the untreated leakage from the MSIVs when isolation of the primary system and containment is required.
GRAND GULF-UNIT 1 B 3/4 6-1 Amendment No. 89 9203090211 920304 PDR ADOCK 0500 6
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