Information Notice 1986-02, Failure of Valve Operator Motor During Environmental Qualification Testing

Failure of Valve Operator Motor During Environmental Qualification Testing

ML031220475
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, 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, Crane
Issue date:	01/06/1986
From:	Jordan E NRC/IE
To:
References
IN-86-002, NUDOCS 8512310466
Download: ML031220475 (3)

SSINS No.: 6835 IN 86-02

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.' 20555

January 6, 1986

IE INFORMATION NOTICE NO.,86-02:

FAILURE OF VALVE OPERATOR MOTOR DURING

ENVIRONMENTAL QUALIFICATIONTESTING

Addressees

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

construction permit (CP).

Purpose

This notice is to alert recipients of a potentially significant-problem involv- ing the failure of Reliance Motor Corporation magnesium motors during environ- mental qualification (EQ) testing of Limitorque valve operators for River Bend

and Nine Mile Point 2 nuclear power stations. It is expected that recipients

will review this information for applicability to their facilities and consider

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

However, suggestions contained in thisinotice do-not constitute

NRC requirements; therefore, no specific action or written response is required.

Description of Circumstances

On August 30, 1985, the General Electric Company (GE) reported to theNRC that

they had experienced test anomalies of the Reliance, class RH, ac motors during

EQ testing of a Limitorque fast-acting SMB-3-150 valve motor operator for its

Gulf States Utilities (River Bend) and Niagara Mohawk (Nine Mile Point 2) BWR

customers. These motors have magnesium rotors. Magnesium rotor motors have

previously undergone EQ testing by Limitorque (PWR Qualification - Project

600456A) without failures.

However,-during the current testing, three motors

'failed during the 100-day design-basis-event (DBE) test.

The first motor had

been subjected to the 40-year qualification series of radiation, thermal, mechanical, and dynamic aging before the loss-of-coolant-accident (LOCA)

testing. This motor had been exposed for 7 days to a steam environment with

temperatures-as high as 3550F when the-rotor bar at the interface with the end

ring had corroded, causing separation of the end ring from the conducting bars.

A second (unaged) motor was then substituted into the test; after 14 days in

the steam environment, with a maximum-temperature of 2450F, it experienced the

same failure as the first motor., A third (unaged) motor experienced the same

failure following 43 days with a maximum temperature of 2230F.

8512310466

Ii

IN 86-02 January 6, 1986 Discussion:

Limitorque Corporation has used Reliance medium and large (180 frame and larger)

ac motors, with magnesium alloy as-a standard rotor material, in its operators, for many years. Although all specific applications and affected power plants

could not be identified, Limitorque has concluded that all domestic nuclear

power facilities, using Limitorque actuators, would have several motors in

180-frame size and larger containing magnesium alloy rotors.

The magnesium

alloy rotors have been primarily used where high-torque, high horsepower, fast-acting motors are required. Reliance Motor Corporation has stated that, while they are reviewing possible design changes to prevent corrosion of the

rotor in high temperature steam environments, there are no existing rotors

available to replace the magnesium alloy components and retain the same motor

characteristics.

General Electric has reviewed the BWR applications and has provided recommended

action via Service Information Letter No. 425 (July 17, 1985).

In summary, GE

recommends that licensees determine the plant-specific applications of magnesi- um motors subject to harsh environment, the adequacy of long-term cooling could

be evaluated assuming failure of the magnesium rotor MOVs a few days after the

DBE. Some systems may allow for the operator to position the valve to its safety

position immediately following the DBE instead of waiting for automatic actuation, while other systems may require realignment to a standby mode after initial core

cooling.

In addition to operator training, it may be prudent to disconnect some

.-of_the_valve-actuation logic followingsafety positioning to prevent valve

_

realignment without operator initiation. Other corrective actions may be

appropriate for specific applications.

PWR owners may wish to review their Limitorque MOV qualification packages in

light of this new information.

If the review determines that the equipment may

not be qualified for its intended use then they may wish to consider taking

action, as recommended by GE for BWRs and as described above, to mitigate the

potential for long-term core cooling problems caused by motor-operated valve

(MOV) failures in the days following a DBE.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate regional office or this office.

ward L. Jar an, Director

ivision of mergency Preparedness

and Engineering Response

James E. Stewart, IE

(301) 492-9061 Attachment:

List of Recently Issued IE Information Notices

K>

K)

v

Attachment 1

IN 86-02

January 6, 1986

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information -

Date of

Notice No..

Subject

Issue

-Issued to

86-01

85-101

.1

85-100

85-99 I ,

85-98

85-97

85-96

85-95

85-94 Failure Of Main Feedwater

1/3/86

Check Valve Causes Loss Of

Feedwater System Integrity

And Water-Hammer Damage

Applicability of 10 CFR 21

12/31/85

To Consulting Firms Providing

Training

Rosemount Differential

12/31/85

Pressure Transmitter Zero

Point Shift

Cracking In Boiling-Water-

12/31/85

Reactor Mark I And Mark II

Containments Caused By Failure

Of The Inerting System

Missing Jumpers From Westing- 12/26/85

-house-Reactor Protection- System Cards For The Over-

Power Delta Temperature Trip

Function

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All BWR facilities

having a Mark I or

Mark II containment

All Westinghouse

designed PWR

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All BWR facilities

holding an OL or CP

All power reactor

facilities holding

an OL or CP

Jail Term For Former

Contractor Employee Who

Intent

ionally Falsified

Welding Inspection Records

Temporary Strainers Left

Installed In Pump Suction

Piping

Leak Of Reactor Water To

Reactor Building Caused By

Scram Solenoid Valve Problem

12/26/85

12/23/85

12/23/85 Potential For Loss Of Minimum 12/13/85

Flow Paths Leading To ECCS

Pump Damage During A LOCA

OL = Operating License

CP = Construction Permit