ML17278A530

Tech Specs Changing Time for Purging Through Standby Gas Treatment Sys to 150 H Per 365 Days from Present 90 H Allotted

ML17278A530
Person / Time
Site:	Columbia
Issue date:	12/20/1985
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17278A528	List: ML17278A527 ML17278A530
References
TAC-60345, NUDOCS 8512310084
Download: ML17278A530 (8)

Text

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- ATTACHMENT A CONTAINMENT SYSTEMS DRYWELL ANO SUPPRESSION CHAMBER PURGE SYSTEM LIMITING CONDITION FOR OPERATION

3. 6. 1.8 The drywell and suppression chamber purge system may be in operation with the drywell and/or suppression chamber purge supply and exhaust butterfly isolation valves open for inerting, deinerting, or pressure control, provided that each butterfly valve is blocked so as not to open more than 70 . PURGING through the Standby Gas Treatment System shall be restricted to less than or equal to Pf hours per 365 days.

/Wo APPLICABILITY: OPERATIONAL CONDITIONS 1, 2, and 3.

4 ACTION:

a. With a drywell and/or suppression chamber purge supply and/or exhaust butterfly isolation valve open for other than inerting, deinerting, or pressure control, or not blocked to less than or equal to close the butterfly valve(s) within=1 hour or be, in at leas 70'pen, 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 supply and/or exhaust isolation valve(s) with resilient material seals having a measured leakage rate exceeding the limit of Surveillance Requirement 4. 6. l. 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 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 COLO SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

SURVEILLANCE RE UIREMENTS

4. 6. 1. 8. 1 When being opened, the drywell and suppression chamber purge supply and exhaust butterfly isolation valves shall be verified to be blocked so as to open to less than or equal to 70 open, unless so verified wi hin the previous 31 days.

4.6.1.8.2 At least once per 6 months, on a STAGGERED TEST BASIS, each 24- and 30-inch drywell and suppression chamber purge supply and exhaust isolation valve with resilient material shall be demonstrated OPERABLE by verifying that the measured leakage is:

Less than or equal to 0.05 L per valve tes or,

b. Greater than 4.6. 1.8.2.a. provided that: 1) the valves are secured closed and maintenance performed at the next plant cold shutdown to reduce th leakage to within 4.6. 1.8.2.a; 2) the leakage added to the previously determined total for all valves and penetr ations subject to Type B and C tests per LCO 3/4.6. 1. 2 shall be less than 0.6 L ,

C. In the event the valves are to be operated, and 4. 6. 1. 8. 2. a. has been exceeded, a leakage test must be performed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following operation, to ensure compliance with 0. 6 L .

PDR P

ADOCK 851220 PDR','/4 05000397 5-11 a'512310084 Amendment lo.

CONTAINMENT SYSTEMS SURVEILLANCE REOUIREMENTS Conti nued 4.6. 1.8.3 The cumulative time that the drywell and suppression chamber purge system has been in operation PURGING through the Standby Gas Treatment System shall be verified to be less than or equal to Pd hours per 365 days prior to use in this mode of operation.

g5o WASHINGTON NUCLEAR " UNIT 2 3/4 6-12

CONTAINMENT SYSTEMS BASES 3/4.6.1.5 PRIMARY CONTAINMENT STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the containment steel vessel will be maintained comparable to the original design standards for the life of the unit. Structural integrity is required to ensure that the containment will withstand the maximum pressure of 34.7 psig in the event of a LOCA. A visual inspection in conjunction with Type A leakage tests is sufficient to demonstrate this capability.

3/4.6.1.6 ORYWELL ANO SUPPRESSION CHAMBER INTERNAL PRESSURE The limitations on drywell and suppression chamber internal pressure ensure that the containment peak pressure of 34.7 psig does not exceed the design pressure of 45 psig during LOCA conditions or that the external pressure differential does not exceed the design aximum external pressure differential of 2 psid. The limit of 1.75 psi o initial positive contain-ment pressure will limit the total pressure t .7 psig which is less than the design pressure end is consistent with iety snelysis.

3/4.6.1.7 ORYWELL AVERAGE AIR TEMPERATURE The limitation on drywell average emperature ensures that the containment peak air temperature does exceed the design temperature of 3404F during LOCA conditions and is n stent with the safety analysis.

3/4.6.1.8 DRYWELL ANO SUPPRESSIO BER PURGE SYSTEM The 24-inchand 30-inch d and suppression chambe~ purge supply exhaus tion valves are r ed.to be sealed closed during

, operation since e valves not been demonstrated c of closing during a LOCA or steam ak accident. Mai g these valves sealed jnger~

closed during plant operations e t cessive quantities of radio-active materials will not be re v a urge system. To provide assurance that the 24-i 30-inch valves can inadvertently opened, they are scale ed in accordance with Standard Review 6.2.4, which inclu anical devices to seal or lock the valve closed or pr ower m being supplied to the valve operator.

use of the drywell and suppressi'on chamber purge lines is rest the 2-inc

'o rg supply and exhaust isolation valves sine e the 24-inch and 30-inch va e 2-inch valves will uring a LOCA or steam line break accident'and the h OUNDARY dose guidelines of 10 CFR Part 100 would not be e 1n t e e of an accident during PURGING operations. s gn of the 2-inch purge su exhaust isolation meets the requirements of Branch Technical Pos 6-4, nment Purging Ouring Normal Plant Operations."

Leakage integrity tests with a maximum allowable leakage rate for purge supply and exhaust isolation valves will pi ovide early indication of resilient material seal degradation and will allow the opportunity for repair before gross leakage failure develops. The 0.60 L leakage limit shall not be exceeded when the leakage rates determined ay the leakage integrity tests of those valves are added to the previously determined total for all valves and penetrations subject to Type B and C tests.

I WASHINGTON NUCLEAR - UNIT 2 B 3/4 6-2

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Insert to 3/4.6.1.8 The 24-inch and 30-inch drywell and suppression chamber purge supply and exhaust isolation valves are allowed to be opened during plant operation for the purpose of venting or purging. The 24-inch and 30-inch valves automatically close in the event of a DBA LOCA.

However, these valves have not been analyzed per SRP 6.2.4 and, therefore, usage of these valves is limited to 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> in a year.

The use of the valves limit is intended to lessen the concern that a DBA LOCA could occur wi th the valves open and potentially cause damage to the in-service SGT division. The valves by analyses will close during the postulated LOCA dynamic conditions. However, dynamic tests performed on a similar butterfly-type designed valve indicates relatively large closing torque re8uirements exist when the di~c is from a plane to approximately 20 from plane condition.

The 70 opening limit is to ensure conservative closing torque requirements are maintained throughout the valve stroke.

Branch Technical Position CSB 6-4 design requirements for the 2-inch bypass/exhaust isolation valves are satisfied; therefore, usage of these valves during plant operation is not restricted. These 2-inch valves in the exhaust flow path automatically isolate on a DBA LOCA; therefore, the SITE BOUNDARY dose guidelines of 10 CFR Par t 100 would not be exceeded in the event of an accident during PURGING or VENTING operations.

ATTACHMENT B o During the current 365-day period, shutdown for Maintenance outage 3 (M-3) and subsequent startups with Recirculation Pump B investigation and troubleshooting, the containment was de-inerted and inerted four times. This period (5/3/85 through 7/16/85) consumed approximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />; During the period 7/27/85 through 11/12/85 (100 days at power),

approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> were used to maintain 02 concentration.

A reactor scram on 11/13/85 and subsequent de-inerting and inerting operation consumed 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

In the period from 12/1/85 to date, approximately 30 more hours have been accumulated; 28 for de-inerting and inerting for Recirculation Pump B vibration testing and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> from inerting to maintain 0 concentration. This effort was also required to provide for a dIy-well entry in support of the recirculation pump effort.

It should be noted that the drywell entries listed above were primarily in support of the recirculation pump effort; however, other component failures were attended to during the entries.

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