ML18037A208

Requests Util Commitment to Comply W/Encl Interim Position Re Containment Purge & Vent Valve Operation Pending Resolution of Isolation Valve Operability.Commitment Needed within 45 Days

ML18037A208
Person / Time
Site:	Nine Mile Point
Issue date:	10/22/1979
From:	Ippolito T Office of Nuclear Reactor Regulation
To:	Dise D NIAGARA MOHAWK POWER CORP.
References
NUDOCS 7911190032
Download: ML18037A208 (11)

Text

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Docket Nos. 50-220 OCTOBER 2 2 879 f<r. Donald P. Disc Vice President - Engineering

'iagara Hoha>rk Power Corporation 300 Erie Boulevard West

'yracuse, New York 13202

Dear f<t. Disc:

'istribution ocket ORB 83 NRR Reading Local PDR

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NRC PDR TIppol-ito EReeves Atty, OELD OI8(E (3)

TERA ACRS (16)

SSheppard PPolk RE:

Containment Purging 'and Venting During Normal Operation

-'y letter dated November 29, 1978,.the Commission (NRG) requested all licensees of operating reactors to respond to -generic concerns about containment purging or venting during normal plant operation.

The generic concerns inhere twofold:

(1)

Events had occurred where licensees overrode, or bypassed 'the safety actuation isolation signals to the containment isolation valves.

These events were determined to be abnormal occurrences and reported to Congress in January 1979.

(2)

Recent, licensing reviews haVe required tests or analyses to show that contain'ment purge or vent valves would shut without degrading con-tainmen't integrity during the dynamic loads of a design basis loss of coolant.accident (DBA-LOCA).

VII) taken s stressed t at positive a tions must b

-contairm~ent irrteyri'-ie 4 be maintair iscussions, t s-rroted-ab'ov n..age..event..a e

NRC staff to-assure-th

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......CI3I2 V9>11 The NRC position of the Hoveriber 1978 letter requested that.licensees take the following positive actions pending completion of'he NRC'eview:

(1) prohibit the override or bypass of'ny safety actuation signal which would.affect another safety actuation sign'al; the NRC Office of Inspection and Enforc'ement would verify that administrative controls prevent improper

'anual defeat. of safety actuation signals, and (2 ) cease purging (or venting) of containment or'1'imit purging (or venting) to an absolute minimum, not to exceed 90 hour0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> s per year.

Licensees were requested to demonstrate (by test or by test and an'alysis) th'at containment;isolation valves wo'uld shut under postulated DBA-LOCA condition.

The NRC positions were amplified by citation (and an attached copy) of our Standard Review Plan (SRP). 6.2.4 Revision 1

and the associated Branch Technical Position CSB 6-4< which have effectively. classed the purge and vent valves as "active'nvoking the operability assurance program of SRP 3.9.3.'he NRC staff has made site visits to several facilities, has met with

, Q licensees at Bethesda,

Maryland, and has held telecon conferences with

~ctrrrers.

Durin these NRC FORM 318 (9.76) NRCM 0240 4 V 5 OOVICRNMCNC I'RINTINO OPRICRI I ~ 1 ~

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's a result. of these actions, we have learned from several licensees

,that at'least three valve vendors have reported that their va'Ives may not close against the ascending differential pressure and the resulting dynamic loading of the design basis LOCA.

All identified licensees who are affected have proposed to maintain the valves in the closed position or,to<restrict the, angular opening of the valves whenever primary containment integrity is required until a re-evaluation is provided which shows satisfactory valve performance under the DBA-LOCA condition.

Recently, a report under 10 CFR Part 21-was received by the t<RC from'he manufacturer of butterfly valves which are installed in the primary

- containment at the Three bile Island Unit 2 Nuclear Station.

These butterfly

-valves are used for purge and exhaust purposes and are requir'ed to operate during accident conditions.

The report discusses the use of an unqualified solenoid valve for a safety-related valve function which requires operation under accident conditions.

Thd solenoid valve is used to pilot control the pneumatic valve actuators which are installed on the containment venti'tation butterfly valves at this facility.

Your re-evaluation of valve perf'ormance for conditions noted in the previous paragraph must consider the concerns identified fn IE Bulletin 79-01A..

As the t)RC review progresses, licensees which might have electrical override circuitry problems are being advised not to use the override and to take compensatory interim measures to minimize the problem.

In light of the information gained during our reviews of your submittal dated'anuary 10, 1979, the meeting we had in Bethesda, Maryland on October 15, 1979, and the information cited above,,we believe an interim commitment from you is required at this time.

This is the case, even though you may have proposed Technical Specification changes or, other long or shopt-.term

measures, which v~e are reviewing.

For your use, we have provided as arf attachment an interim NRG staff position.

In addition, our recently developed "Guidelines for Demonstration of'perability of Purge and Vent Valves" were provided by'separate letter to licensees of

,each operating reactor.

This letter in no way relaxes any existing licensing requirements for your. facil ity.

Because of the potential adverse effects on the public health and safety which could result from the postulated, OBA-LOCA while operating with open purge or vent valves, we believe your prompt response to this letter is required.

In accordance with 10 CFR 50.M(f), you ar'e requested Orl IOa~

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.to inform us in writing within 45 days of-receipt of this letter of your commitment to operate in conformance with,the enclosed interim position and to provide us'ith information which demonstrates that you have initiated the purge and vent valve operability verification on an expedited basis.

The information provided in your response will enable us to determine whether or not your license to operate Nine flile Point Nuclear Power Station sho'uld be modified, suspended, or revoked; Sincerely, r

orlgtnal s18ned bf T, A. IppoHto Thomas A. Ippolito, Chief Operating Reactors Branch 83

. Division of-Operating Reactors

Enclosure:

Interim Position for Containment Purge and Vent Valve Operation..

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Mr. Donald P. Disc Niagara Mohawk Power Corporation 4

CC:

Eugene B. Thomas, Jr., Esquire

LeBoeuf, Lamb, Leiby 8 MacRae 1757 N Street, N.

W.

Washington, D.

C.

20036 Anthony Z. Roisman Natural Resources Defense Council 917 15th Street, N.

W.

Washington, D.

C.

20005 Oswego County Office Building 46 E. Bridge Street

Oswego, New York 13126

INTERIM POSITION FOR CONTAINMENT PURGE AND VENT VALVE OPERATION PENDING RESOLUTION OF ISOLATION VALVE OPERABILITY Once the conditions listed below are met, restrictions on use of the containment purge and vent system isolation valves will be revised based on our review of your responses to the November 1978 letter justifying your proposed operational mode.

The revised restrictions can be established separately for each system.

1.

Whenever the containment integrity is required, emphasis should be placed on operating the containment in a passive mode as much as possible and on limiting all purging and venting times to as low as achievable.

To justify venting or purging, there must be an established need to improve working conditions to perform a safety related surveillance or safety related maintenance procedure.

(Examples of improved working conditions would include deinerting, reducing temperature*,

humidity*,

and airborne activity sufficiently to permit efficient performance or to significantly reduce occupational radiation exposures),

and 2.

Maintain the, containment purge and vent isolation valves closed whenever the reactor is not in the cold shutdown or refueling mode until such time as you can show that:

a.

All isolation valves greater than 3" nominal diameter used for containment purge and venting operations are operable under the most severe design basis accident flow condition loading and can close within the time limit stated in your Technical Specifications, design criteria. or operating procedures.

The operability of butter-fly valves

may, on an interim basis, be demonstrated by limiting the valve to be no more than 30'o 50'pen (90'eing full open).

The maximum opening shall be determined in consultation with the va'Ive supplier.

The valve opening must be such that the critical valve parts will not be damaged by DBA-LOCA loads and that the valve will tend to close when the fluid dynamic forces are introduced, and b.

Modifications, as necessary, have been made to segregate the containment ventilation isolation signals to ensure that, as a minimum, at least one of the automatic safety injection actuation signals is uninhibited and operable to initiate valve closure when any other isolation signal may be blocked, reset, or overridden.

Only where temperature and humidity controls are not in the present design.

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UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 Mr. Donald P. Disc Vice President - Egnineering Niagara Mohawk Power Corporation 300 Erie Boulevard West

'yracuse, N. Y.

13202 Eugene B.

Thomas, Jr.,

Esquire

LeBoeuf, Lamb, Leiby 8

MacRae l757 N Street, N.

W.

Washington, D.

C.

20036 Anthony Z.

Roisman Natural Resources Defense Council 917 15th Street, N.

W.

Washington, D.

C.

20005 Oswego County Office Building 46 E. Bridge Street

Oswego, New York 13126 Docket File NR Local PDR ORBt"3 Rdg NRR Rdg H. Denton E.

Case D. Eisenhut B. Grimes W. Gammill R. Vollmer L.

Shao J. Miller T. Ippolito R.

Reid A. Schwencer E.

Adensam V. Noonan G.

Knighton D.

Ziemann P.

Check G. Lainas

. D. Crutchfield F.

Pagano R. Clark OELD OIEE (3)

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Sheppard Project Manager ACRS (16)

NRC Participants TERA J.

R.

Buchanan

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