ML20236H313

Summary of 870707 Meeting W/Util & Westinghouse Re Interlocks for RCS Loop Isolation Valves.List of Attendees & Licensee Presentation Encl

ML20236H313
Person / Time
Site:	Millstone
Issue date:	07/24/1987
From:	Ferguson R Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8708050138
Download: ML20236H313 (16)

Text

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July 24,1987

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00CKEiNO.50-423 LICENSEE: Northeast Nuclear Energy Company FACILITY: Millstone Nuclear Power Station, Unit 3

SUMMARY

OF MEETING TO DISCUSS INTERLOCKS FOR THREE LOOP OPERATION On July 7,1987, representatives of the NRC staff and Northeast Nuclear Energy Company (NNECo) met to discuss the interlocks for the reactor coolant system (RCS) loop isolation valves.

Enclosed is a list of attendees and copies of the licensee's presentation.

The licensee presented a chronology of this issue, and described how three loop operation would be used, the procedures for changing the loop configurations, accident analysis that has been done, and the safety importance of the interlocks on the RCS loop isolation valves. The highlights of the discussion are as follows:

1.

Transition from 4-loop to 3-loop operation during operation will be done with the reactor power below 37% of full power while maintaining the plant within its technical specification limits.

2.

Transition from 3-loop to 4-loop operation will be done in Mode 5 Cold i

Shutdown.

3.

Power will be removed from the RCS loop isolation valves in the isolated loop when the plant is operating with a 3-loop RCS configuration.

4.

The licensee will document the additional information discussed in this meeting related to the safety importance of the interlocks by August 3, 1987 The staff will complete its review within 60 days thereafter.

/S/

Robert Ferguson, Project Manager Project Directorate I-4 Division of Reactor Projects I/II

Enclosures:

As stated cc w/ enclosures:

See next pace PDk PDI-4 PDI-4 l

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RFerguson;eh JStoy 1/4Y/87

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B700050138 h h 23 PDR ADOCK PDR P

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8 Mr. E. 'J. Mroczka Millstone Nuclear Power Station Northeast Nuclear Energy Company Unit No. 3 I

Cc:

Gerald Garfield, Esq.

Ms. Jane Spector Day, Berry & Howard Federal Energy Regulatory Comission l

City Place 825 N. Capitol Street, NE

(

Hartford, Connecticut 06103-3499 Room 8608C

{

Washington, D.C.

20426 Mr. Maurice R. Scully, Executive Director Mr. Kevin McCarthy, Director Connecticut Municipal Electric Radiation Control Unit Energy Cooperative Department of Environmental Protection 268 Thomas Road State Office Building Groton, Connecticut 06340 Hartford, Connecticut 06115 Robert W. Bishop, Esq.

Burlington Electric Department Corporate Secretary c/o Robert E. Fletcher, Esq.

Northeast Utilities 271 South Union Street Post Office Box 270 Burlington, Vermont 05402 Hartford, Connecticut 06141 i

Mr. Thomas Shedlosky Senior Resident Inspector Office U. S. Nuclear Regulatory Commission Millstone III i

P. O. Box 811 Niantic, Connecticut 06357-08 Mr. Michael L. Jones, Manager Project Management Department j

Massachusetts Municipal Wholesale Electric Company Post Office Box 426 Ludlow, Massachusetts 01056 Regional Administrator U. S. NRC, Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Mr. Karl Abraham Public Affairs Office, Region I U. S. Nuclear Regulatory Comission, King of Prussia, Pennsylvania 19406

4 MILLSTONE UNIT 3 NRC/NNECO THREE LOOP OPERATION MEETING-JULY 7, 1987 LIST OF ATTENDEES.

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Name 0 organization R. L. Ferguson NRR/PDI-4 l

'T. E. Collins NRR/ DEST /RSB

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Fred Burrows NRR/ DEST /ICSB Walter L. Brooks NRR/ DEST /RSB Kenneth Burton

-NNECo/ Operations David McDaniel NNECo/ Engineering Carl Clement NNECo/MP-3 Supt Ravi Joshi NU Licensing l

Gilbert Olsen NUSCo/I&C Engineering l

l T. A. Schaffer NUSCo/I&C Engineering Bob Sterdis-Westinghouse Licensing Philip W. Rosenthal Westinghouse Transient Analysis l

4 t

a MILLSTONE UNIT NO, 3 STATUS OF THREE (N-1) LOOP LICENSE APPLICATION FOR OPERATING LICENSE l

OCTOBER 1982 l

SAFETY EVALUATION REPORT (SER) ISSUED JULY 1984 ACRS MEETING AUGUST 1984 NOVEMBER 1984 REQUESTED APPROVAL FOR THREE-LOOP OPERATION MARCH 1985 SER SUPPLEMENT 1 ISSUED l

SEPTEMBER 1985 SER SUPPLEMENT 2 ISSUED NOVEMBER 1985 SER SUPPLEMENT 3 ISSUED SER SUPPLEMENT 4 ISSUED LOW-POWER OPERATING LICENSE (0L) WITH THREE-

).

LOOP LICENSE CONDITION FULL-POWER OL WITH THREE-LOOP LICENSE JANUARY 1986 CONDITION MEETING WITH l&C STAFF JULY 1986 NNECO SUBMITTAL TO ADDRESS 1&C OPEN ITEMS AUGUST 1986 l

NOVEMBER 1986 MEETING WITH l&C STAFF MEETING WITH l&C STAFF FEBRUARY 1987 NNECO SUBMITTAL TO ADDRESS 1&C OPEN ITEMS NRC ISSUED REACTOR SYSTEM SAFETY EVALUATION MEETING WITH HUMAN FACTORS STAFF MARCH 1987 APRIL 1987 NRC TO ISSUE 1&C SER NRC TO REMOVE THREE-LOOP LICENSE CONDITION

~l MILLSTONE UNIT 3' N-1 LOOP

( 3 LOOP ) OPERATION I

I

-1 THREE LOOP OPERATION WILL NOT BE A NORMAL METHOD OF PLANT OPERATION 2

THREE LOOP OPERATION WILL ONLY BE USED IN OFF NORMAL CONDITIONS TO PREVENT'A PREMATURE SHUTDOWN OF THE UNIT EXAMPLES OF PROBLEMS WHICH MIGHT FORCE 3 LOOP OPERATION l

REACTOR COOLANT PUMP PROBLEMS j,

SEAL FAILURES PUMP MOTOR PROBLEMS l

l VIBRATION i

i SMALL STEAM GENERATOR TUBE LEAKS IN EXCESS OF THE TECHNICAL SPECIFICATION LIMIT BUT NOT LARGE ENOUGH TO BE CONSIDEREL CATASTROPHIC i

MAIN STEAM ISOLATION VALVE FAILURES.

PROBLEMS ASSOCIATED WITH INSTRUMENTATION THAT IS LOOP SPECIFIC

( S/G LEVEL, HOT AND COLD LEG TEMPERATURE, RCS FLOW 1)

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THREE LOOP OPERATION WILL BE USED TO KEEP THE PLANT ON LINE IN ORDER TO ALLOW PLANNING OF A MORE ORDERLY OUTAGE, OR TO MEET A PLANNED SHUTDOWN DATE EXAMPLES AN RCP PUMP DEVELOPS HIGH VIBRATION ONE MONTH PRIOR TO AN EXPECTED REFUELING.

RATHER THAN SHUTDOWN ONE MONTH EARLY, THREE LOOP OPERATION WILL ALLOW THE UNIT TO MEET THE EXPECTED REFUELING DATE A SMALL STEAM GENERATOR TUBE LEAK DEVELOPS REQUIRING A COLD SHUTDOWN.

ECT EQUIPMENT FROM THE VENDOR IS NOT AVAILABLE FOR ANOTHER WEEK.

THREE LOOP OPERATION ALLOWS OPERATION UNTIL THE OUTAGE CAN BE PLANNED.

i e

4 ACTUAL NORTHEAST UTILITIES EXPERIENCE IN NEEDING THREE-i LOOP OP2 RATION WINTER 1970 CONNECTICUT YANKEE l

l Approximately two months prior to to a scheduled refueling I

i tube leakage in excess'of the Technical. Specification minimum developed.

Rather than shutting down for repairs two months prior to the end of the cycle the unit was operated in 3' loop operation for approximately two 1

months.

I SPRING 1983 CONNECTICUT YANKEE While in the process of returning to operation following a refueling a problem developed with one Reactor Coolant Pump and a-Pressurizer Safety Valve.

Both problems required a cold shutdown for repair.

Rather than cooling down immediately Low Power Physics Tests were perf ormed in three loop operation.

Physics tests revealed that four i

control. rod drive shafts were not connected to the control rods.

Perf ormance of Physics tests. in three loop detected an additional problem

')

there by preventing a second shutdown.

Prevention of a second outage saved additional radiation exposure, additional thermal cycles on the pl ant, and allowed for a higher unit capacity factor.

i

_____._..__._____._.______________.________i

SPRING 1983 MILLSTONE UNIT 2

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Leakage in one Steam Generator exceeds the Technical Speci f i cati on limit.

The unit is put in COLD SHUTDOWN and repairs are I

begun.

Due to the unplanned nature of the outage manual rather than l

automatic ECT and plugging equipment is used causing additional radiation I

exposure.

A ref ueling outage is scheduled in two months.

I I

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FALL 1985 MILLSTONE UNIT 2 1

I While returning to power following a short shutdown an i

electrical problem develops with an Reactor Coolant Pump Motor. The unit i

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goes to cold shutdown for three weeks. Repairs are made to the motor.

The following refueling the motor is replaced.

WINTER 1907 MILLSTONE UNIT 2 Following a refueling additional problems with ECT data

.are discovered forcing a cold shutdown for further repairs.

It is estimated that the use of manual rather than automated equipment, and the forced nature of the outage caused and additional 25 MAN REM of exposure over a planned outage with automated equipment.

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SUMMARY

I 1

THREE LOOP OPERATION IS NOT CONSIDERED TO BE A NORMAL 1

1

' METHOD OF OPERATION 2

HAVING AN OPTION FOR THREE LOOP OPERATION ALLOWS FOR BETTER PLANNING IN FORCED OUTAGE SITUATIONS

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BETTER PLANNING RESULTS IN LESS RADIATION EXPOSURE, i

HIGHER UNIT CAPACITY FACTORS, SAVINGS IN DOLLARS, AND SAVINGS IN TIME.

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Four Loop to Three Loop Transition

]

Maior Steps

1. Reduce reactor power below P8 (37%)

2. Perform Main Board switch lineup for 3 loop operation

3. Perform I&C surveillance for N-1 operation 1

4. Remove loop from service

- open bypass valve

- stop reactor coolant pump i

- close cold leg stop valve

- establish fill and drain to affected loop

- close hot leg stop valve

- close main steam isolation valve 4

J

5. Cool down isolated loop

6. Unisolate 1500 psia loop relief valve l

1

'.g a

Three Loop to Four Loop Transition Major Steps

1. Establish affected loop temperature <170*F

2. Drain affected loop

3. Put plant in Mode 5

(<170*F) 1

4. Establish VCT Boron concentration > RCS Boron concentration

5. Fill affected loop

6. Check VCT Boron concentration, repeat drain and fill if less than RCS Boron concentration

7. Complete Ops. Dept. Tech Spec surveillance for return to four loop operation l

8.

Stop all reactor coolant pumps

9. Open loop stop valves

10. Complete I&C surveillance for return to four loop operation

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• Distrib$ tion.

h Docket File

.O NRC & l.ocal PDRs l

PD I-4 Reading RFerguson JStolz

'0GC-Bethesda EJordan JPartlow ACRS (10)

'HBClayton l

TECo111ns-WBrooks FBurrows

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