ML20154C507

Proposed Tech Specs Bases Page B 3/4 9-2,removing Wording Re 10% Value for Clad Gap Iodine Isotopics

ML20154C507
Person / Time
Site:	South Texas
Issue date:	09/30/1998
From:	HOUSTON LIGHTING & POWER CO.
To:
Shared Package
ML20154C498	List: ML20154C507 NOC-AE-000302, Informs That STP TS Bases Page B 3/4 9-2 Has Been Changed by Removing Wording of 10% Value for Clad Gap Iodine Isotopics. Copy of Revised TS Page,Encl
References
NUDOCS 9810060293
Download: ML20154C507 (2)

Text

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2 ATTACHMENT REVISED TECHNICAL SPECIFICATION BASES (PAGE B % 9-2)

"J 1883! 318382 ,8 P PDR

, ,, n - REFUELING OPERATIONS BASES l

3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLANT CIRCULATION The requirement that at least one residual heat removal (RHR) loop be in operation ensures that: (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor vessel below 140 F as required during the REFUELING MODE, and (2) sufficient coolant circulation is maintained through the core to minimize the effect of a boron dilution incident and prevent boron stratification. 1 The requirement to have two RHR loops OPERABLE when there is less than 23 feet of water above the reactor vessel flange ensures that a single failure of the operating RHR loop will not result in a complete loss of residual heat removal capability. With the reactor vessel head

)

removed and at least 23 feet of water above the reactor pressure vessel flange, a large heat sink is i available for core cooling. Thus, in the event of a failure of the operating RHR loop, adequate time is provided to initiate emergency procedures to cool the core.

1 3/4.9.9 CONTAINMENT VENTILATION ISOLATION SYSTEM l The OPERABILITY of this system ensures that the containment purge and exhaust penetrations will be automatically isolated upon detection of high radiation levels in the purge ,

exhaust. The OPERABILITY of this system is required to restrict the release of radioactive  !

material from the containment atmosphere to the environment. I 3/4.9.10 and 3/4.9.11 WATER LEVEL - REFUELING CAVITY AND STORAGE POOLS The restrictions on minimum water level ensure that sufficient water depth is available to ,

remove 99% of the assumed iodine gap activity released from the rupture of an irradiated fuel l l assembly. The minimum water depth is consistent with the assumptions of the safety analysis.

3/4.9.12 FUEL HANDLING BUILDING EXHAUST AIR SYSTEM l The limitations on the Fuel Handling Building Exhaust Air System ensure that all radioactive material released from an irradicted fuel assembly will be filtered through the HEPA filters and charcoal adsorber prior to discharge to the atmosphere. Operation of the system with the heaters operating for at least 10 continuots hours in a 31-day period is sufficient to reduce the buildup of moisture on the adsorbers and HEPA filters. The OPERABILITY of this system and the resulting iodine removal capacity are consistent with the assumptions of the safety l analyses. ANSI N510-1980 will be used as a crocedural guide for surveillance testing. This Specification has been modified by a note that states, at least one FHB exhaust air filter train, one l

FHB exhaust booster fan, and one FHB main exhaust fan are capable of being powered from an i Onsite emergency power source. This note ensures that required FHB exhaust train components l will have an emergency power source available, even if the limiting conditions for operation can l be satisfied.

SOUTH TE.XAS - UNITS 1 & 2 B 3/4 9-2 Unit 1 - Amendment No.40,74 Unit 2 - Amendment No.4&-40 12075-97

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