ML20215M537

Informs That 860919 Justification for Interim Operation Until Backup Containment Spray Valve MO-7068 Qualificiation Status Remedied Acceptable to Warrant Continued Operation Until Refueling Outage Scheduled to Begin on 860102

ML20215M537
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	10/17/1986
From:	Zwolinski J Office of Nuclear Reactor Regulation
To:	Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
TAC-62866, NUDOCS 8611030009
Download: ML20215M537 (4)

Text

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[ o "g UNITED STATES o NUCLEAR REGULATORY COMMISSION

<) WASHINGTON, D. C. 20585 h -

k...+/ October 17, 1986 Docket No. 50-155 Mr. Kenneth W. Berry Director, Nuclear Licensing Consumers Power Company 1945 West Parnall Road Jackson, Michigan 49201

SUBJECT:

dttSTIFICATION FOR INTERIM OPERATION FOR BACKUP CONTAINMENT SPRAY VALVE M0-7068 (TAC 62866)

Re: Big Rock Point Plant During an NRC audit, conducted during the week September 15, 1986, at the Pig Rock Point Plant.(BRPP), compliance to 10 CFR 50.49 Environmental Qu'alification (EQ) was inspected. During the audit it was discovered that uncertainties exist in the qualification status of the BRPP backup containment spray valve actuator. Details as to'the "as found" status of this valve and the entire inspection will be provided in the NRC Region III Inspection Report. Of immediate concern to both NRC and Consumers Power Company (CPCl is the safe operation of the BRPP particularly since the BRPP is currently operatina at or near full rated power. Since the BRPP backup containment spray system is required to mitigate the consecuences of a certain size class of Main Steam Line (PSti Break accidents, justification for interim operation until the qualification status of the valve in question could be remedied, was requested by the NRC staff.

By letter dated September 19, 1986, CPC provided the requested justification for interim operation for the BRPP. The letter provided a description of the events that culminated in the conclusion that the backup containment spray valve M0-7068 E0 is in Question, identification of CPC's imediate actions taken to justify actuator operability for the short term, and a description of the planned longer term actions to effect full cualification.

The NRC staff has reviewed CPC's justification for interim operation of the BRPP and finds the justification acceptable to warrant continued operation until the BRPP 1987 refueling outage. The BRPP 1987 refueling outage is

' currently scheduled to comence on January 2,1987. NRC staff acceptance of the justification was based primarily on the following:

8611030009 861017 PDR ADOCK 05000155 P PDR

Mr. Kenneth L. Berry October 17, 1986 1.

The BRPP containment spray system is not required to prevent exceeding containment design pressure during a LOCA or steam line break events.

Certain size MSL breaks, however, can cause enclosure temperature to exceed the temperature profile associated with certain electrical equipment oualification assumptions. The NRC staff notes, more importantly, that containment spray flow is not required to prevent exceeding the containment design pressure, as documented in BRPP Technical Specification (TS) 11.3.3.4 bases. Specifically, initiation of the containment spray system assures that containment design pressure will not be exceeded due to hydrogen generation assuming the core spray systems do not function. It has been conservatively calculated that the energy release following a complete core meltdown (assuming no containment spray systems or core spray systems operatei would bring the containment pressure to apprOFimately the design value (27 psipi about 15 minutes after the postulated accident had occurred.

Subsequent BRpP LOCA analysis system modifications and regulations have limited H 2 eneration such that it is no longer significant and calcula-tions show that containment sprays are not required to prevent containment

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design pressures from being exceeded. These conclusions are " key" to the

,iustification for interim operation of the BRPP.

2. BPPP historical records have shown that the valve IMO-70681 has not experienced any failures to operate throughout its inservice life since it was LOCA tested. Additional testing, at this time, would require an entry into a limiting condition for operation requiring the concurrent removal from service of a redundant core spray line.

3. Valve M0-7068 failure to close, after 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of post-accident environment, is more likely than failure to open shortly after the initiating event.

A BPPP Emergency Procedure 3.3 revision to restrict the use of only one containment spray header for iodine washdown activities provides protection from the diversion of required core spray flow since the fire pumps provide both core and containment spray flow.

4. By letter dated January 13, 1981, the NRC issued a Safety Evaluation

to CPC which stated tnat the BRPP minimum required containment spray flow was 50 gpm for the most limiting containment temperature rise (due j to an MSLB). The required calculated valve position for M0-7068, as l documented by CPC letter dated October 10, 1986, assuming total failure of M0-7064, is approximately 10% of full open. Therefore a full valve stroke is not required to achieve minimum required containment spray flow.

Based on the information and analyses provided by CPC, the current schedule for the 1987 Refueling Outage, and CPC plans to effect full qualification at the earliest possible opportunity, NRC staff finds the justification for interim operation acceptable such that the BRPP be permitted to operate until the start of the 1987 refueling outage.

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Mr. Kenneth L. Berry October 17, 1986 NRC staff recommends th'at CPC use this opportunity to coordinate and/or conduct tests on the M0-7068 actuation, subsequent to its removal, to demonstrate the operability of this type of valve in co. sideration of its calculated age and prior LOCA test exposure.

If you should have any questions regarding the information presented above, please contact your NRC BRPP Project Manager.

Sincerely, pianed bye John A. Zwolinski, Director BWR Project Directorate #1 Division of BWR Licensing cc: See next page DISTRIBUTION:

Docket File NRC PDR Local PDR BWD1 Reading RBernero OGC-Beth.

GHolohan EJordan i BGrimes l JPartlow l

Glainas NThompson TRotella CJamerson ACRS (10)

BRP File JZwolinski NChrissotimos-RIII l

l DBL:BWD#1 DBL:BW #1 DBL:BWD#1 l CJamerson TRotella JZwolinski 10/ib /86 10/lb/86 10/11/86

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l Mr. Kenneth W. Berry Consumers Power Company Big Rock Point Plant cc:

Mr. Thomas A. McNish, Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Big Rock Point Plant ATTN: Mr. David P. Hoffman Plant Superintendent Route 3 Post Office Rox 591 Charlevoix, Michigan 49720 Mr. I. Lee Moerland Chairman, Board of Commissioners P. O. Box 218 Charlevoix, Michigan 49720 Office of the Governor Room 1 - Capitol Puilding Lansing, Michigan 48913 Regional Administrator Nuclear Pegulatory Commission, Region III 799 Poosevelt Road Glen Ellyn, Illinois 60137 Nuclear Facilities and Environmental Nonitoring Section Office Division of Radiological Health P. O. Box 30035 Lansing, Michigan 48909

, Resident Inspector Big Rock Point Plant c/o U.S. NRC RR #3, Box 600 Charlevoix, Michigan 49720 l

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