ML20059G986

Proposed Tech Specs 3.6.1.6 Bases Addition

ML20059G986
Person / Time
Site:	05200001
Issue date:	10/21/1993
From:	GENERAL ELECTRIC CO.
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ML20059G980	List: ML20059G977 ML20059G986
References
NUDOCS 9311090231
Download: ML20059G986 (1)

Text

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Wetwell-to-Drywell Vacuum B 3.6.1.6  :

i BASES SURVEILLANCE SR 3.6.1.6.1 (cor,tinued)

REQUIREMENTS i

(continued) indication or2 by increasing the drywell pressure by '

O.035 kg/cm above the wetwell pressure and verifying tha the pressure differential does not fall below 0j021Lk#cm}d for 15 minutes without makeup. Thisl criteH a_lwas! developed ,

assuming idealf gis behsvior.JiileakageTareaicorrespondinghto l 10% of theLallowable:le'akagetareaMthe.;temperaturesdinlthel  :

wetwell and. drywell remained"nearlyTconstantLthroughout;the testing-- interval, c nd:!t.

a hat.L adequate: instrumentation!ferist(

to:measureLthe pres's'ure:decayt : Ba~ sing the1testLcriteriaton J 10% off the allowable leakage; area lprovides.tallargefdegreeiof '

margin in demonstrating lthatithelvacuumibreakerspare

, adequately closed andisealed ! Additionally,Lif Jthe l allowable leakageTarea were tolexistk a: pressure 2

i' differential of 0.0351kg/cm fwould. decay completelyNithin 15-minutes. -Maintaining.the! average temperaturestof.th'e ~

wetwell 1and - drywell - i s E importanti becauselthej piessure? ' 3 4

diffarentials 'in- this test are relativelffsmalliandianibe significantlyLimpacted by;small?temperatureichanges.

Changestin average temperatures':greateritha'n:1!025*C invalidate the test' parameters. 1(However control is~a problem, new test l parameters lgif temperatupe

_should;be ~

developed which take into accountith.einormaD temperat'urs variations'.).

The 14 day Frequency is based on engineering judgment, is considered adequate in view of the fact that the vacuum breakers are normally biased closed by gravity forces. This

, verification is also required within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after any discharge of steam to the wetwell from the safety / relief valves or any operation that causes the drywell-to-wetwell differential pressure to be reduced by 2 0.007 Kg/cm 2d.

i  !

)

l SR 3.6.1.6.2 ,

4 Each requireo vacuum breaker must be cycled to ensure that i it opens adequately to perform its design function and l returns to the fully closed position. This ensures that the safety analysis assumptions are valid. The 18 month Frequency of this SR is based on the need to perform the surveillance during an outage. The vacuum breakers can only I be manually actuated and are only accessible during an I

, outage.  :

l

, (continued)

ABWR TS B 3.6-41 10/21/93 l

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