Information Notice 1985-22, Failure of Limitorque Motor-Operated Valves Resulting from Incorrect Installation of Pinion Gear

Failure of Limitorque Motor-Operated Valves Resulting from Incorrect Installation of Pinion Gear

ML031180403
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date:	03/21/1985
From:	Jordan E NRC/IE
To:
References
IN-85-022, NUDOCS 8503190659
Download: ML031180403 (4)

SSINS No.: 6835 IN 85-22 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 March 21, 1985 IE INFORMATION NOTICE NO. 85-22: FAILURE OF LIMITORQUE MOTOR-OPERATED

VALVES RESULTING FROM INCORRECT

INSTALLATION OF PINION GEAR

Addressees

All nuclear power reactor facilities holding an operating license (OL) or a

construction permit (CP).

Purpose

This information notice is provided to alert recipients of a potentially signi- ficant problem pertaining to the incorrect installation of pinion gears in

Limitorque motor-operated valves. It is expected that recipients will review

the information for applicability to their facilities and consider actions, if

appropriate, to preclude a similar problem occurring at their facilities.

However, suggestions contained in this notice do not constitute NRC require- ments; therefore, no specific action or written response is required.

Description of Circumstances

On December 21, 1984 and February 20, 1985, the Tennessee Valley Authority

reported [Licensee Event Report (LER) 84-013] failure of the outboard high

pressure coolant injection (HPCI) valve to open at the Browns Ferry Nuclear

Power Station Unit 3. Operators observed the failure while attempting to

perform an operability surveillance on the HPCI system.

An inspection of the Limitorque operator revealed that the pinion gear had been

installed in a reversed position. This reversed installation resulted in only

about one third of the normal gear mesh surface and the complete wearing away

of the portion of the pinion gear teeth that were in contact with the shaft

(drive) gear. With the pinion gear teeth worn away, the motor could no longer

operate the valve. This inspection also revealed that the DC shunt field for

the operator had failed. With the shunt field open, the valve travel speed was

limited only by load. A review of completed surveillances since 1980 revealed

that the travel time for the valve had been about 8 seconds. This is approx- imately one half of the normal travel time of 16 seconds and may have acceler- ated the gear tooth erosion.

8503190659

IN 85-22 March 21, 1985 Discussion:

A similar problem was found at Browns Ferry Nuclear Power Station Unit 1 (LER

79-035 reported January 2 and March 11, 1980, and February 12, 1981) and at

Unit 2 (LER 80-2 reported March 11, 1980).

Several factors contribute to the potential for the reverse installation of the

pinion gear, including the following: (1) the reverse installation is rela- tively easy and not readily detected by observation, (2) the reverse instal- lation is not revealed in postmaintenance testing (except for Limitorque

operator Types SMB 00 and SMB 000), and (3) the pinion is installed in one

direction in certain types of Limitorque operators while in others it is

properly reversed 1800. Because Limitorque valve operators are used for many

safety-related valve applications, the unexpected failure of a valve to operate

electrically could be very significant.

Corrective actions initiated by the licensee include:

1. Conducting a sampling of accessible safety-related Limitorque valve

operators to ensure correct pinion gear installation. Should the sampling

give a positive indication that other safety-related Limitorque valve

operators are suspect, develop a program for their inspection to precede

corrective action 4 below.

2. Adding a requirement for independent verification of the correct installa- tion of pinion gear to applicable maintenance procedures. -

3. Adding a caution statement to applicable maintenance and electrical

procedures to ensure that personnel verify the correct Limitorque valve

operator model, and to warn that incorrect installation cannot be detected

in postmai'ntenance testing and can lead to unexpected failure of the valve.

4. Adding inspection of the pinion gear installation and gear tooth wear to

the preventive maintenance program for Limitorque valve operators.

5. Adding the inspection of the shunt field for primary containment isolation

valve dc operators to the Limitorque valve operator inspection program.

6. Providing training on proper pinion gear installation and the failure mode

for Limitorque valve operators to all responsible crafts personnel, including electricians.

IN 85-22 March 21, 1985 notice.

No specific action or written response is required by this information

contact the Regional Admin-

If you have any question about this matter, please

istrator of the appropriate NRC regional office or this office.

Director

Divi n of Emergency Preparedness

an Engineering Response

Office of Inspection and Enforcement

Technical Contacts: Silas David Stadler, RII

(404) 221-5600

Richard J. Kiessel, IE

(301) 492-8119 Attachment: List of Recently Issued IE Information Notices

Attachment 1 IN 85-22 March 21, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-21 Main Steam Isolation Valve 3/18/85 All PWR facilities

Closure Logic holding an OL or CP

85-20 Motor-Operated Valve Failures 3/12/85 All power reactor

Due To Hammering Effect facilities holding

an OL or CP

85-19 Alleged Falsification Of 3/11/85 All power reactor

Certifications And Alteration facilities holding

Of Markings On Piping, Valves an OL or CP

And Fittings

85-10 Posstensioned Containment 3/8/85 All power reactor

Sup. 1 Tendon Anchor Head Failure facilities holding

an OL or CP

84-18 Failures Of Undervoltage 3/7/85 All Westinghouse

Output Circuit Boards In The PWR facilities

Westinghouse-Designed Solid holding an OL or CP

State Protection System

83-70 Vibration-Induced Valve 3/4/85 All power reactor

Sup. 1 Failures facilities holding

an OL or CP

85-17 Possible Sticking Of ASCO 3/1/85 All power reactor

Solenoid Valves facilities holding

an OL or CP

85-16 Time/Current Trip Curve 2/27/85 All power reactor

Discrepancy Of ITE/Siemens- facilities holding

Allis Molded Case Circuit an OL or CP

Breaker

85-15 Nonconforming Structural 2/22/85 All power reactor

Steel For Safety-Related facilities holding

Use an OL or CP

85-14 Failure Of A Heavy Control 2/22/85 All power reactor

Rod (B4C) Drive Assembly facilities holding

To Insert On A Trip Signal an OL or CP

OL = Operating License

CP = Construction Permit