Information Notice 1988-84, Defective Motor Shaft Keys in Limitorque Motor Actuators

Defective Motor Shaft Keys in Limitorque Motor Actuators

ML031150062
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
Issue date:	10/20/1988
From:	Rossi C E Office of Nuclear Reactor Regulation
To:
References
IN-88-084, NUDOCS 8810140018
Download: ML031150062 (3)

4.UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 October 20, 1988 NRC INFORMATION

NOTICE NO. 88-84: DEFECTIVE

MOTOR SHAFT KEYS IN LIMITORQUE

MOTOR ACTUATORS

Addressees

All holders of operating

licenses or construction

permits for nuclear power reactors.

Purpose

This information

notice is being provided to alert recipients

to potential problems from defective

motor shaft keys installed

in certain Limitorque

actuators.

It is expected that recipients

will review the information

for applicability

to their facilities

and consider actions, as appropriate, to avoid similar problems.

However, suggestions

contained

in this information

notice do not constitute

NRC requirements;

therefore, no specific action or written response is required.Description

of Circumstances:

On October 15, 1987, the NRC received a report from Houston Lighting and Power Company concerning

sheared motor shaft-to-pinion

keys found in a Limitorque

actuator at its South Texas Project, Unit 2, nuclear plant. A similar key'failure also occurred in April 1987. The sheared key from one of the valves.was sent to a metallurgical

laboratory

which found that the properties

of the-.material were not consistent

with those of American Iron and Steel Institute (AISI) type 1018 steel. AISI type 1018 steel is the material designated

by Limitorque

for these particular

keys as specified

in Limitorque

design documents.

In August 1987, three additional

keys had been removed from similar actuators and sent to the laboratory

for analysis.

One of the removed keys was split and the other two showed signs of deformation.

Laboratory

analysis of these keys revealed that the properties

of the key material were not consistent

with those of AISI type 1018 steel. The metallurgical

analysis revealed that the keys had failed longitudinally

along manganese

sulfide inclusions

and that the key material was probably an AISI type 1118 or 1119 resulphurized

steel. Addi-tionally, on March 16, 1983, Westinghouse

had submitted

a 10 CFR Part 21 report to the NRC concerning

its discovery

of sheared keys on six actuators.

These keys were also analyzed and found to be made of other than AISI type 1018 steel.Discussion:

During an NRC inspection

at Limitorque

in May 1988, inspectors

found that at the time of the manufacture

of the South Texas actuators, keys were purchased<0 At101t40018 IN 88-84 October 20, 1988 from a commercial

vendor without certificates

of conformance

for the material type or properties.

No checks were performed

at Limitorque

to verify that the proper key material was received.

Keys purchased

today are still bought as commercial

grade; however, certified

material test reports (CMTRs) are received from the vendor. Limitorque

also performs hardness and dimensional

checks of the keys upon receipt from the vendor.In a letter to the NRC dated May 19, 1988, Limitorque

provided additional

in-formation

on this issue. Limitorque

stated that the current material control procedures

for key procurement

were fully implemented

in September

1983. At that time, the existing key inventory

was scrapped and completely

replaced with keys purchased

under the new controls.

It is estimated

that all actuators

from serial number 362735 onward were supplied with keys procured under the upgraded material controls.

Additionally, Limitorque

determined

that only the following actuator-motor

combinations

could potentially

experience

similar key failures due to improper material.Unit Size Motor Size SMB-000 None SMB-OO 25-ft.lb 1800 rpm SMB-0 25-ft.lb 1800 rpm 25-ft.ThY

-3600 rpm--40-ft.lb 1800 rpm SMB-1 60-ft.lb 1800 rpm 60-ft.lb 3600 rpm SMB-2 80-ft.lb 3600 rpm No specific action or written response is required by this information

notice.If you have any questions

about this matter, please contact the technical contact listed below or the Regional Administrator

of the appropriate

regional office.Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 Attachment:

List of Recently Issued NRC Information

Notices

, 0 A -%If Attachment

IN 88-84 October 20, 1988 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 88-83 88-82 88-81 88-80 88-79 Inadequate

Testing of Relay Contacts in Safety-Related

Logic Systems Torus Shells with Corrosion and Degraded Coatings in BWR Containments

Failure of Amp Window Indent Kynar Splices and Thomas and Betts Nylon Wire Caps During Environmental

Quali-fication Testing Unexpected

Piping Movement Attributed

to Thermal Stratification

Misuse of Flashing Lights for High Radiation

Area Controls 10/19/88 10/14/88 10/7/88 10/7/88 10/7/88 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for BWRs.All holders of OLs or CPs for nuclear power, test, and research reactors.All holders of OLs or CPs for PWRs.All holders of OLs or CPs for nuclear power reactors.88-69, Supp 1 Movable Contact Finger Binding in HFA Relays Manufactured

by General Electric (GE)9/29/88 All holders of OLs or CPs for nuclear power reactors.88-78 88-77 88-76 Implementation

of Revised NRC-Administered

Requali-fication Examinations

Inadvertent

Reactor Vessel Overfill Recent Discovery

of a Phenomenon

not Previously

Considered

in the Design of Secondary

Containment

Pressure Control 9/22/88 9/22/88 9/19/88 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for BWRs.All holders of OLs or CPs for nuclear power reactors.OL = Operating

License CP = Construction

Permit