Information Notice 1986-71, Recent Identified Problems with Limitorque Motor Operators

Recent Identified Problems with Limitorque Motor Operators

ML031250108
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:	08/19/1986
From:	Jordan E NRC/IE
To:
References
IN-86-071, NUDOCS 8608150010
Download: ML031250108 (4)

LI S P161 SSINS NO.

IN 86-71 6835 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 August 19, 1986 IE INFORMATION NOTICE NO. 86-71: RECENT IDENTIFIED PROBLEMS WITH

LIMITORQUE MOTOR OPERATORS

Addressees

All nuclear power reactor facilities holding an operating license or a

construction permit.

Purpose

This notice is provided to alert recipients of two potential problems discovered

with Limitorque motor operators. It is expected that recipients will review this

information for applicability to their facilities and consider actions, if

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

However, suggestions contained in this notice do not constitute NRC requirements;

therefore, no specific action or written response is required.

Past Related Documents:

IE Information Notice 86-03 "Potential Deficiencies in Environmental Qualification

of Limitorque Motor Valve Operator Wiring," January 14, 1986.

Description of Circumstances

- Burn Damage to Internal Wiring

On November 8, 1985 Georgia Power Company submitted a preliminary report to the

NRC indicating that it had discovered burn damage to internal wiring in several

Limitorque motor operators installed in their Vogtle Unit 1 Power Plant.

Evidence suggested the burn damage had been caused by electric heater elements

installed in the limit switch compartment for storage purposes within certain

types of Limitorque motor operators.

On March 20, 1986 Georgia Power Company submitted a final report to the NRC

which suggested that the burn damage was a generic problem applicable to all

Limitorque motor operators. This assumption was based on a sampling inspection

of 104 Limitorque motor operators installed in Vogtle Unit 1. Forty-six of the

motor operators examined were Limitorque type SMB-000, and six of these were

found to have burnt internal wiring. Out of the 58 operators other than type

SMB-OOO which were inspected, 5 were found to contain wires deemed susceptible

to damage because of their close proximity to the heater elements (less than

h inch).

8608150010

IN 86-71 August 19, 1986 On May 20, 1986 an NRC inspector, along with Limitorque, Georgia Power, and

Bechtel personnel, performed a random inspection on four type SMB-000 operators

installed in Vogtle Unit 2. Three of the four operators were found to contain

burnt internal wiring. One type SMB-OO operator also was inspected and was

found to contain wiring susceptible to damage.

Discussion:

The wiring in question is Limitorque installed internal wiring located in the

operator limit switch compartment. The wiring is being burnt as a result of

its close proximity to, or contact with, the installed limit switch compartment

electric heater element or heater bracket. The wiring is not properly routed

and is not restrained from contacting the heater or heater bracket. Although

the heater is not a seismically or environmentally qualified part and is intended

for use only during storage, its use has been shown to cause serious degradation

of environmentally qualified internal wiring.

The burnt wiring has been discovered only in Limitorque type SMB-OOO motor

operators that contain previously energized heaters, although any Limitorque

operator that contains a previously energized heater could possibly exhibit a

similar problem.

Description of Circumstances

- Cracked Limit Switch Rotors

Several licensees have submitted reports to the NRC concerning a problem with

cracked limit switch rotors on Limitorque motor operators installed inside and

outside of containment. The limit switches are used for control of the motor

operator and also provide indication of valve position in the control room.

The cracks have been found on white melamine limit switch rotors. Most of these

cracks were found in the area where the limit switch rotors are pinned-to the

pinion shafts. Some cracks have been found to extend halfway through the

melamine rotors, weakening them to the extent that they are easily broken.

Discussion:

In its letter dated February 21, 1984 to the Westinghouse Electric Corporation, Electro Mechanical Division, Cheswick, Pennsylvania, Limitorque recommended

that any white limit switch components which are found with cracks should be

replaced with components manufactured with a later design, brown colored material.

Violations of 10 CFR Part 21 have been issued to Limitorque for failure to report

and for failure to evaluate defects discovered in their motor operators. Licensees

are reminded of their responsibility to ensure that procurement documents include

a contractual requirement that the provisions of 10 CFR Part 21 apply (when

applicable) and that Criterion VII of 10 CFR Part 50 Appendix B requires that

purchased material, equipment, and services conform to the requirements of the

procurement documents.

IN 86-71 August 19, 1986 No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional Admin- istrator of the appropriate NRC regional office or this office.

Edward L. 4ordan, Director

Division Xf Emergency Preparedness

and Eng neering Response

Office of Inspection and Enforcement

Jeffrey Jacobson, IE

(301) 492-8845 Attachment: List of Recently Issued IE Information Notices

Attachment 1 IN 86-71 August 19, 1986 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

86-70 Spurious System Isolation 8/18/86 All GE BWR facilities

Caused By The Panalarm Model holding an OL or CP

86 Thermocouple Monitor

86-69 Scram Solenoid Pilot Valve 8/18/86 All BWR facilities

(SSPV) Rebuild Kit Problems holding an OL or CP

86-68 Stuck Control Rod 8/15/86 All BWR facilities

holding an OL or CP

86-67 Portable Moisture/Density 8/15/86 All NRC licensees

Gauges: Recent Incidents And authorized to possess, Common Violations Of Require- use, transport, and

ments For Use, Transportation, store sealed sources

And Storage

86-66 Potential For Failure Of 8/15/86 All power reactor

Replacement AC Coils Supplied facilities holding

By The Westinghouse Electric an OL or CP

Corporation For Use In Class

lE Motor Starters And

Contractors

86-65 Malfunctions Of ITT Barton 8/14/86 All power reactor

Model 580 Series Switches facilities holding

During Requalification Testing an OL or CP

86-64 Deficiencies In Upgrade 8/14/86 All power reactor

Programs For Plant Emergency facilities holding

Operating Procedures an OL or CP

86-63 Loss Of Safety Injection 8/6/86 All PWR facilities

Capability holding an OL or CP

86-62 Potential Problems In West- 7/31/86 All power reactor

inghouse Molded Case Circuit facilities holding

Breakers Equipped With A an OL or CP

Shunt Trip

OL = Operating License

CP = Construction Permit