ML20247R686

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Proposed Tech Specs Re Primary Containment Nitrogen Venting & Pressure Control
ML20247R686
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 07/24/1989
From:
DETROIT EDISON CO.
To:
Shared Package
ML20247R679 List:
References
NUDOCS 8908080082
Download: ML20247R686 (4)
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Text

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CONTAINMENT SYST_ EMS DRYWELL AND SUPPRESSION CHAMBER PURGE SYSTEM e-

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LIMITING CONDITION FOR OPERATION 3.6.1.8 The drywell and suppression chamber purge system (6-inch, 10-inch, 20-inch, and 24-inch valves) may be in operation with the supply and exhaust isolation valves in one supply line and one exhaust line open for inerting, ,

deinerting or pressure control f r e/ vent operations through the SGTS shall ited to 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> each 265 davf. Ndroyer Vagrws/mkegg .,,2 f renu, e contvd 15 eiro al/cgo d -thrw h Y 4. l-4,1 WIVCS BILITY: DPERATIONA. CONDITIONS 1, 2, and 3. ]

ACTIONi  ;

a. With a drywell and suppression chamber purge system supply and/or exhaust isolation valve open, except as permitted above, close the valve (s) or otherwise isolate the penetration (s) within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
b. With a drywell and suppression chamber purge system supply and/or exhaust isolation valve (s) with resilient material seals having a sea-  ;
sured leakage rate exceeding the limit of S'. edification 4.6.1.8.2, '

restore the inoperable valve (s) to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or e I be in at least HOT S:;UTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD \ I SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. -

l l SURVEILLANCE REQUIREMENTS I f

4.6.1.8.1 Before being opened for purge / vent operation through SGTS, the drf-well and suppression chamber purge supply and exhaust butterfly isolation

_, valves shall be verified not to have been open for purge / vent operation through SGTS for more than 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> in the previous 365 days.*

4.6.1.8.2 At least once per 92 days each penetration for each 6-inch, each l 10-in:h, each 20-inch, and each 24-inch drywell. and suppression chamber purge supply and exhaust isolation valve with resilient material seals shall be demonstrated OPERABLE by verifying that the measured leakage rate is less than or eoual to 0.05 L, when pressurized to P,.

I avalves-s, pen--fer pr ::ur: cente:1 r: n:t :ubjec4. t: th: 90 5:ur p:r 355 d:y m it p-ovided the S-inch byp::: lin: !: b:ing utilized. .

4 femrf cenlainmerl rufrogen vwrwG ad presrurt confed is fumfed broh @

l Inas valves ad is nd suijed -h 1h 90 houre pr 565 a'sy /$n}.

l FERMI - UNIT 2 '3/4 6-14

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I CONTAINMENT SYSTEMS .

BASES __

PRIMARY CONTAINMENT AIR LOCKS (Continued) 3.6.1.2. The specification makes allowances for the fact that there may be j long periods of time when the air locks will be in a closed and securedOn j position during reactor operation.is required to maintain the integrity of the cont 3/4.6.1.4 MSIV LEAKAGE CONTROL SYSTEM Calculated doses resulting from the maximum leakage allowance for the main steamline isolatfen valves in the postulated LOCA situations would be a small fraction of the 10 CFR Part 100 guidelines, provided the main steam Ifne system from the isolation valves up to and including the turbine condenser remains occurred intact. in the leak tightness of the TheMSIVs requh ement such that the requirements have not alvays been maintainedthecontinuously.for MSIVs th when isolation of the pri: nary system and containment is required.

3/4.6.1.5 PRIMARY CONTAINMENT STRUCTURAL INTEGRITY jgrity of th containment This limitation ensures that the structural .

will be maintained compe %1e to the original design standards for the life of Struct9ral integrity is required to ensure that the contaitaent A the unit.

will withstand the maximum pressure of 56.5 psig in the ev demonstrate this capability.

3/4.6.1.6 DRYWELL_AND SUPPRESSION CHAMBER INTERNAL PRESSURE

- The limitations on drywell and suppression chamber internal pressure j ensure that the containment peak pressure of 56.5 psig dees not exceed the maximum allowable pressure of 62 psig during LOCA conditions or that the l

' externa) pressure differential does not exceed the design maximum external  !

pressure differential of 2 psid. ses y TNSEE7' l 3 /4. 6.1. 7 DRYWELL AVERAGE AIR TEM)ERATURE ' b/' 8 ,

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The limitation on drywell average air temperature ensures that the ~

containrrent peak air temperature does not exceed the design temperature 340'F during LOCA conditions and is consistent with the safety analysis.

3/4.6.1.8 DRYWELL AND SUPPRESSION CHAMBER PURGE _ SYSTEM i teakage integrity tests with a maximum allowable leakage rate for purge supply and exhaust isolation valves will provide early indication of resilien material seal degradation and will allow the opportunity for repair before The 0.60 L, leakage limit shall not be gross leakage failure develops.

exceeded when the leakage rates detemined by the leakage integrity tests these valves are added to the previously determined total for all valves and penetrations subject to Type B and C tests.

FERMI - UNIT 2 B 3/4 6-2

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DEERr B 3/4.6.1.8

%e drywell and suppression chamber purge supply and edianst isolation )

valves are maintained closed during~ a majority of the plant operating time. Maini;aining them valves closed (even though. they have been-qualified to close against the' buildup of pressure in primary.

containment in the event of DBA/LOCA) reduces th potential for release of' excessive quantities of radioactive material.

Purging or venting through the. Standby Gas Treatment System' (SGTS)'

inposes a vulnerability factor on the integrity of the SGTS. Six".11d a  : j{

LOCA occur. while the purge pathway is through'.the SGTS the associated pressure surge, before the purge valves close, may adversely affect the integrity of the SGTS charcoal filters.: ' %erefore, PUEING or VENTI!G through the SGTS is limited to 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> per 365 days. This time' limit is not inposed when venting through the SGTS.with the 1-inch valves ~or when PUMI!G or VENfING thrmgh the Reactor Building ventilatica System with any of the purge valves.

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' ' * ~ TMs p'y 2d4 &< [esfemafors Gely CONTAINMENT SYSTEMS BASES DRYWELL AND SUPPRESSION CHAMBER PURGE SYSTEM (Continued) .

The 6, 10, 20, and 24 inch purge valves are generally configured in a three (3) valve arrangement at each of the associrted purge penetrations. The valves are leak tested by pressurizing between th three valves and a total leakage is determined as opposed to a single valve leakage. Verifying that the measured leakage rate is less than 0.5 L, for this multi-valve arrangement is more conservative than a limit of 0.5 L, for a single valve. l 3/4.6.2 DEPRESSURIZATION SYSTEMS The specifications of this section ensure that the primary containment ]

pressure will not aceed the maximum allowable pressure of 62 psig during primary system blowdown from full operating pressure.

The suppression chamber water provides the heat sink for the reactor coolant f' system energy release fc110 wing a postulated rupture of the system. The suppres-sion chamber water volume must absorb the associated decay and structural sen-sible heat released during reactor coolant system blowdown from 1040 psig.

Since all of the gases in the drywell are purged into the suppression chamber 1 air space during a loss-of-coolant accident, the pressure of the liquid must not exceed 62 psig, the suppression chamber maximum pressure. The design volume of the suppression chamber, water a' n d air, was obtained by considering 4 that the total volume of reactor coolant tt, be condensed is discharged to the s"ppression chamber and that the drywell volume is purged to the suppression c,>ambe r. l l

e FERMI - UNIT 2 8 3/4 6-3

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