ML19309F840

Forwards Request for Addl Info to Complete Review of Containment Leakage Testing Exemption Request.Response Due within 30 Days

ML19309F840
Person / Time
Site:	Prairie Island
Issue date:	04/11/1980
From:	Schwencer A Office of Nuclear Reactor Regulation
To:	Mayer L NORTHERN STATES POWER CO.
References
NUDOCS 8005010422
Download: ML19309F840 (5)

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DISTRIBUTION:

APR 11 GSG oocket no. 50-282/306 NRC PDR Local PDR ORB Rdg NRR Rdg DEisenhut Docket t:cs. 50-282 BGrimes and 50-306 WGammill Attorney, OELD 01&E (3)

ASchwencer Mr'. L. O. Mayer,itanager MGrotenhuis CParrish Nuclear Support Services NS Northern States Power Company 414 Nicollet Mall 8th Floor

!!inneapolis, liinnesota 55401 ACRS (16)

JHuang Glainas

Dear lir. Mayer:

!!e have reviewed your August 9,1975 request for -exemption froa certain require:nents of Appendix J to 10 CFR Part 50, Containe.ent Leakage Testing, for the Prairie Island Plcnt.

We find that we need the additional information i

indicated in the enclosure to this letter in order to make a decision on your request.

We request this information be provided within 30 days of your reccipt of this letter.

Sincerely, Original Signed By A Schwencer A. Schwencer, Chief i-Operating Reactors Branch il Division of Operating Reactors

Enclosure:

Request for Additional Information s

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, rt FCRM 3 ;5 t9 % W". ONa D U.S.'GO y E L v. ENT PRINTING OFFICC; ]979-2 89 369 Mr. L.- 0. Mayer Ncrthern States Pcwer Ccapany cc: Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.

Washington, D. C.

20036 Ms. Terry Hoffman Executive Director Minnesota Pollution Control Agency 1935 W. County Road 52 Poseville,. Minnesota 55113 The Environmental Conservation Library Minneapolis Public Library 300 Nicollet Mall-Minneapolis, Minnesota 55401 Mr. F. P. Tierney, Plant Manager

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Prairie. Island Nuclear Generating Plant Northern States Power Company Route 2 Welch, Minnesota 55089 Joclyn F. Olson, Esquire Special Assistant Attorney General Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville, Minnesota 55113 Robert L. Nybo, J r., Chai rman Minnesota-Wisconsin Scundary Area Commission 619 Second Street Hudson, Wisconsin 54016 Clarence D. Fierabend Resident Inspector Prairie Island Nuclear Generating Plant U. S. Nuclear Regulatcry Commission P. O. Box 374 Red Wing, Minnesota 55066 E

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1.0 SACKGROUND In a le::er dated 9 August 1976, Northern States ?over Cc=pany (NS?)

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i requested exemption from certain require =en:s of 10CyR50, Appendix J, Centain-cent Leakage Testing.

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l 2.0 'INFORMATION REQUIRED

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2.1 EXEMPTION REQUEST "a" i

1 NS? stated tha: Fan Ceil Unit isolation valves are in syste=s " sealed" i

frc: containment a::csphere.

To justify an exe p:icn fre Type C testing l

requirements of Appeni1x J f or these valves, previde :he fellowing inf er:ation.

I 1.

A descriptien of hev the syste: is sealed (e.g.,

safety class l

syste: designed to retain full of water fellering a postulated TOCA).

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A description cf hev the seal integrity is verified (e.g., hydre-static tes: to de::nstrate that the syste vill re ain full of-vater for 30 days following a' postulated LOCA).

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A discu'ssion of her the " sealed" syste: vill function to prevent atmospheric leakage.

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'2. 2 EXEMPTION REQUESTS "b" AND'"e" i

The request for exe:ption fre= testing the airlock door seals at a reduced-i pressure within three days af ter being used is acceptable for op2 rating reactors.

l Eevever, the test result = at this reduced pressure =ust be extrapolated to full 4

pressu're to deter =ine tne acceptability of the test.

Sub=i: a descriptien of i

t the ex:rapolation cethod you'propo'se.to use.

-2.2 EXEMPTION REQUEST "c" NSF stated tha: :here' is no assurance : hat the testing,of certain valves.

a in a direction opposite :: that of'their safety functicn vill produce resul:s

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equivalent to er-cre conservative than results obtained from testing in'the l

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dire::i:n Of the pcs:-a::ident pressure.

In :ha: case, testing in the direction

f :he pes:-acciden: pressure vill be required.

E:vever, shcuid these valves be analyzed such :ht: ycu can provide a basis for de:errining tha: reverse direction testing udll produce results equivalent to.or : re censervative-:ha: testing in.the direc:1'en of the safety function, reverse direction testing veuld be acceptable.

If a basis for justification of continued testing in the reverse directicn cannot be provided, sub=it a plan of acticn to confer: with the requirements of Appendix J, including a scledule for the accc plishtent of the plan.

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.r NS? s:st d tha: the Technical Specifica: ions at' Prairie Island Station perzi: a large number of isolation valves to be hydros:stically tested in lieu

f the pneucatic tes:'ng required by Appendix J and tha where hydrostatic es-ing is u:ilized, an ippr:priate air / vater cer:ela:ica f actor is applied.

This app:cach is theoretically acceptable if a justifica: ion for the validity cf :e air /va:er cerrela:1en can be p cvidec.

E:vever, since the leakage

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invclved is generally quite lev and also since the leakage path characteristics are essentially unpred'c:able, it is extre ely difficul: to correlate va:er

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easage accura:e,-

..: ca:e, ne accep;able corre.2a-

icn has been de ns::a:ed in this area.

Nevertheless, hyd:cstatic testing of :hese valves say be acceptable where

he syste= is designed to re ain intact and liquid-filled folleving a postulated Icss-of-ecolant accident.

For these systers, testing with water as a medium is ::re appropriate than testing with air or nitrogen since it more closely app::xica:es the post-accident environment.

If hydrostatic testing is to be empicyed, justification cust be provided that the available fluid inventory is sufficien: to =aintain a water seal on the isolation valves during and follow-tag an accident based en the leakage-rate lini: cf the test.

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~ e: a of Table 1, cencerning Appendix J, Secticn III.A.l(d), states:

he pri:ar:. sys:e= is vented :o the cen:ai. en: atmosphere, but coolan: is not drained to expcse sys t:s ec= unicating vi:h :he pri=ary system to the air tes: pressure.

Each systen is, hevever, subjected to Type C tes if. practicable.

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