ML20004D860

Forwards Contractor Final Evaluation for SEP Topic III-10.A, Thermal Overload Protection for Motors of Motor Operated Valves. Requests Summary of History of Motor Operated Valve Performance within 30 Days of Receipt of Ltr

ML20004D860
Person / Time
Site:	Millstone
Issue date:	06/04/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Counsil W NORTHEAST NUCLEAR ENERGY CO.
References
TASK-03-10.A, TASK-3-10.A, TASK-RR LSO5-81-06-012, LSO5-81-6-12, NUDOCS 8106100236
Download: ML20004D860 (6)

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Tkff June 4, 1981

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Occket No. 50-245 LS05 06-012 f

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Mr. W. G. Counsil, Vice President h'

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Nuclear Engineering and Operations No.heast Nuclear Energy Cogany

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P. O. Box 270 Hartford, Connecticut 06101

SUBJECT:

SEP TOPIC III-10.A THERMAL-0VERLOAD PROTECTION FOR MOTORS OF POTOR OPERATED VALVES (MILLSTONE 1)

We have enclosed our contractor's final evaluation for SEP Topic 111-10.A.

The revised report reflects the additional infor: nation and sorre of the coments provided in your April 16, 1981 letter.

The igact with regard to the use of torque switches at yo'ur plant will be addressed in our integrated assessment report.

Although the Regulatory Guide publishing Criterion 3 has not yet been issued, operating plant experience with spurious torque switches actuation has shown that it is prudent to bypass torque switches over the first 10". of valve travel. The purpose of this bypass is to ;ermit the motor and valve parts to come to operating speed and generate breakaway torque above the normal running torque.

You should provide within 30 days of receipt of this letter a su. mary of the history of motor operatad valve performance at your plant to enable the staff to reach a detemination regarding spurious toroue switch actuation at your facility.

Sincerely, Dennis M. Crutchfield, Chief n

Operating Reactors Branch No. 5

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• ir. John E. Maier Vice President -

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Roche r Gas M1ectric Corporation 89 East ut/

Rochester, York 14649

SUBJECT:

SEP TOPIC III-10.A, THERMAL-0VERLOAD PROTECTION FOR MDTORS OF MOTOR OPERATED VALVES (MILLSTONE 1)

We have enclosed our contractor's final evaluation for SEP Tcpic III-10.A.

The revised report reflects the additional information and some of the comments provided in your April 16, 1981 letter.

The impact with regard to the use 'of torque switches.at your-plant will be addressed in our integrated assessment report.

Although the Regulatorj Gaide publishing Criterion 3 has not yet been issued, operating plant experience with spurious torque switches actuation has shown that it is prudent to bypass torque switches over the first 10% of valve travel. The purpose of this bypass is to per' nit the motor and valve parts to come to operating speed and generate breakaway torque above the normal running torque.

You should prsvide within 30 days of receipt of this letter a summarj of the history of motor operated valve performance at ycur plant to enable the staff toraach a determination regarding spurious torque switch l

actuation at your facility.

Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing

Enclosure:

AD:CA:DL Topic III-10.A Final Report GLainas w w/enctow re.

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g June 4, 1981 Docket No. 50-245 LS05-81 012 Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Northeast Nuclear Energy Company P. O. Box 270

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Hartford, Connecticut 06101

SUBJECT:

SEP TOPIC III-10.A THERMAL-0VERLOAD PROTECTION FOR MOTORS OF MOTOR OPERATED VALVES (MILLSTONE 1)

We have enclosed our contractor's final evaluation for SEP Topic III-10. A.

The revised report reflects the additional information and some of the comments provided in your Acril 16, 1981 letter.

The impact aith regard to the

.e of toroue switches at your plant will be addressed in our integratad assessment report.

Although the Regulatory huide publishing Criterion 3 has not yet been issued, operating plant experience with spurious torque switches actuation has shown that is is prudent to bypass torque switches over the first 10% of valve travel.

The purpose of this bypass is to permit the motor and valve parts to come to operating speed and generate breakaway torque above the normal running torque.

You should provide within 30 days of receipt of this letter a summary of the history of.mtor operated valve performance at your plant to enable the staff to reach a determination regarding spurious torque switch actuation at your facility.

Sincerely, Dennis M. Crutchfield, Ch' f Operating Reactors Brai.ch No. 5 s

Division of Licensing

Enclosure:

Topic III-10. A Final Report cc w/ enclosure:

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Mr. W. G. Counsil cc William H. Cuddy, Esquire Connecticut Energy Agency Day, Berry & Howard ATTN: Assistant Director Counselors.at La,a Research and Policy

'One Constitution Plaza Development Hartford, Connecticut 06103 Department of Planning and Energy Policy Natural Resources Defense Council 20 Grand Street 91715th Street, N. W.

Hartford, Connecticut 06106 Washington, D. C.

20005 Director, Criteria and Standards Division Northeast Nuclear Energy Company Office of Radiation Programs ATTN: Superintendent (ANR-460)

Millstone Plant U. S. Environmental Protection P. O. Box 128 Agency Waterf ord, Connecticut 06385 Washingtca, D. C.

20460 Mr. Jaces R. Himmelwright U. S. Environmental Protection Northeast Utilities Service Coapany Agency P. O. Box 270 Region I Office Hartford, Connecticut 06101 ATTN: EIS C0ORDINATOR JFK Federal Building Resident Inspector Boston, Massachusetts 02203 c/o U. S. NRC P. O. Box Draier KK Niantic, Connecticut 06357 Waterford Public Library Rope Ferry Road, Route 156 Waterford, Ccnnecticut 06385 First Selectman of the Town of Waterford Hall of Records 200 Boston Post Road Waterford, Connecticut 06385.

John F. Opeka Systers Superintendent Northeast Utilities Service Cotpany P. O. Box 270.

Hartford, Connecticut 06101 i

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i SEP TECHNICAL' EVALUATION TOPIC III-10.A THERMAL-0VERLOAD PROTECTION FOR MOTORS 0F MOTOR-OPERATED VALVES FINAL DRAFT MILL 3 TONE 1 Docket No. 50-245 l

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SEP TECHNICAL EVALUATION TCPIC III-10.A THERMAL-0VERLOAD PROTECTION FOR MOTORS OF t.40 TOR-0PERATED VALVES MILLSTONE 1 TCPIC III-10.A Thermal-Overload Protection for Motors of Motor-Ocerated Valves The objective of this review is to provide assurance that the appli-cation of thermal-overload protection devices to motors associated wi th safety-related motor-operated valves do not result in needless hindrance of the valves to perform their safety functions.

In 'accordance with this objective, the application of either one of the two recommendations contained in Regulatory Guide 1.106, " Thermal-Overload Protection for Electric Motors on Motor-Operated Valves," is ade-quate.

These recommendations are as follows:

(1 ) Provided that the c,ompletion of the safety function is not jeopardi:ed or that other safety systems are not

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degraded, (a) the thermal-overicad protection devices should be continuously bypassed and temporarily placed in force only when the valve motors are undergoing periodic or maintenance testing, or (b) those thermal-overload protection devices that are normally in force during plant operation snould be bypassed under acci-dent conditions.

(2) The trip setpoint of the thermal-overload protection devices should De established with all uncertainties resolved in favor of completing the safety-related action. With respect to those uncertainties, consider-ation should be given to (a) variations in the ambient temperature at the installed location of the overload protection devices and the valve motors, (b) inaccura-cies in motor heating data and the overload protection i

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device trip characteristics and the matching of these two items, and (c) setpoint drift.

In order to eitsure continued functional reliability and tne accuracy of the trip point, the thermal-overload protection device should be periodically tested.

In addition, the current licensing criteria require that:

(3)

In MOV designs that use a torque switch to Ifmit the opening or closing of the valve, the autcmatic opening or closing signal should be used in conjunction with a corresponding limit switch.

DISCUSSION Cn February 7,1980 Northeast Utilities submitted a list of all safety-related motor-operated valves and the electrical schematics for those valves.4 The licensee subsequently revised the list, deleting six valves and supplying additional information.

Of 59 safety,-related MOVs, 33 have thermal-overload devices which provide alarm only;. the TOLs are not in the valve control circuits. The remaining 21 valves have thermal-overload protection devices which are not bypassed; there is no docketed information to indicate that TOL trip setpoints have been set to comply with all the variables of Criterior 2, above. Nine of these valves are for containment isolation and are normally closed; they should not be required to opcrate during an accident. Additionally, 48 valva open functions and 54 valve close functions are terminated by torque switches rather than limit switches.

EVALUATION D1ermal-overload protection for motors of motor-operated valves :t Mil' stone 1 does not comply with current licensing criteria. Thermal -

overload protection devices are not bypassed, no information is available to support adequacy of trip setpoints, and for uost of the valves, torque switches rather than limit switches ara used to terminate valve travel.

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s REFERENCES 1.

IEEE Standard 179-1971, " Criteria for Protection Systems for iluclear l

Raser Generating Stations."

2.

8rsnch Technical Position EICSB-27, "Cesign Criteria for Thermal Over-load Protection for Motors of Motor-Cperated Yalves."

3.

" Regulatory Guide 1.106, " Thermal Overload Protection for Electric Motors on Motor-Operated Valves."

4.

Letter, Northeast Utilities (Counsil) to NRR (Ziemann), dated February 7,1980.

5.

Letter, Northeast Utilities (Counsil) to NRR (Crutchfield), dated April 16,1981.

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