ML18025B680

Proposed Revisions to Tech Spec 4.7 Re Surveillance Requirements,Containment Sys.Justification Encl

ML18025B680
Person / Time
Site:	Browns Ferry
Issue date:	10/19/1981
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18025B678	List: ML18025B677 ML18025B679 ML18025B680
References
TVA-BFNP-TS-168, NUDOCS 8110280277
Download: ML18025B680 (5)

Text

UNIT 3 PROPOSED CHANGES SiiOiq Bli0280277 05000259 PDR ADOCK P PDR

"

LZMZTING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS co~~E& SYsXXM 4 7 CONT INMENT SYST MS three and one-third year intervals so that any ten-year interval would include four ILRT~s.

" These intervals may be extended up to ten months necessary if to coincide with refueling outage.

f. Except for the initial ZLRT, all ZLRT~s shall be performed without leak repairs immediately prior to or during the test.

Zf leak repairs are necessary in order to perform ZLRT, they shall

'be preceded by local leak measurements where- possible.

The leak rate difference prior to and after repair shall be added to final integrated leak rate results, L~

ox Lt ~

Following each ZLRT, if measured leak the

margin to allow for leakage deterioration which may occur during the period between leak rate tests.

The primary containment leak rate test frequency is based on maintaining adequate assurance that the leak rate remains within the specification. The leak rate test frequency is based on the NRC guide for developing leak rate testing and surveillance of reactor containment vessels. Allowing the test intervals to be extended up to 10months permits some flexibility needed ta have the tests coincide with scheduled or unscheduled shutdown periods.

The penetration and air purge piping leakage test frequency,'

il along with the containment leak rate tests, is adequate to allow detection of leakage trends. Whenever a bolted double-gasketed penetration is broken and remade, the space between the gaskets is pressurized to determine that the seals are performing properly. Zt is expected that the majority of the leakage from valves, penetrations and seals would be into the

~

However, it is possible that leakage into other parts reactor'uilding.

of the facility could occur. Such leakage paths that may affect significantly the consequences of accidents are to be minimized.

The primary containment is normally slightly pressurized during period of reactor operation. Nitrogen used for inerting could leak out of the containment but air could not leak in to increase oxygen concentration. Once the containment is filled with nitrogen to the required concentration, determining the oxygen concentration twice a week serves as an added assurance that the oxygen c'oncentzation will not exceed 4%.

3.7.B/3.7.C Standb Gas Treatment S stem and Seconda

'ontainment The secondary containment is designed to minimize any ground level release of radioactive materials which might result from a.

serious accident. The reactor building provides secondary containment during reactor operation, when the drywell is sealed and in service; the reactor building provides primary containment when the reactor is shutdown and the drywell is open, as during refueling. Because the secondary containment is an integral part of the complete containment system, secondary containment is required at all times that primary. containment is required as well as during refueling.

The standby gas treatment system is designed to filter and

'exhaust the reactor building atmosphere to the stack during secondary containment isolation conditions. All three standby qas treatment system fans are designed to automatically start containment isolation and to maintain the reactor building 'pon pressure to the design negative pressure so that. all leakage should be in-leakage.

291

ENCLOSURE 2 JUSTIFICATION (TVA BFNP TS 168)

These proposed changes increase the extension period for performing the leak rate testing (ILRT) for the primary containment from 'ntegrated eight months to ten months and bring this specification into conformance with Standard Technical Specifications. This change only allows ILRT intervals to be extended if necessary and does not change or effect any safety system.'our ILRT's will still be performed in any ten-year period as rdquired by 10'CFR Part 50.

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