Information Notice 1993-26, Grease Soldification Causes Molded-Case Circuit Breaker Failure to Close

Grease Soldification Causes Molded-Case Circuit Breaker Failure to Close

ML031080033
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Crane
Issue date:	01/31/1994
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-026, Suppl 1, NUDOCS 9401250302
Download: ML031080033 (8)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555

January 31, 1994 NR2' INFORMATION NOTICE 93-26, SUPPLEMENT 1: GREASE SOLIDIFICATION CAUSES

MOLDED-CASE CIRCUIT BREAKER

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is Issuing this information

notice to supplement information regarding a problem with a 400-amp frame,

600-V ac molded-case circuit breaker manufactured by General Electric

Corporation (GE) (Part No. TJK436Y400) which failed to close when required due

to grease solidification. 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 are not NRC requirements; therefore, no specific

action or written response is required.

Description of Circumstances

On March 26, 1992, an engineered safety feature (ESF) actuated at the

Nine Mile Point Nuclear Station Unit 2 (NMP2) because of the loss of output

power from an uninterruptible power supply (UPS) while the loads were being

transferred from UPS power to the maintenance supply power. During the

transfer, the maintenance supply output circuit breaker (CB-4) failed to

close, causing a loss of power to the standby gas treatment system radiation

monitoring cabinet, a false-high radiation signal, a group 9 (primary

containment purge system) primary containment isolation, the loss of a control

room fire panel annunciator, and a loss of communication between the radiation

monitoring system computer and non-Class IE radiation monitors. The operator

immediately took corrective action to close circuit breaker CB-4 manually to

restore the UPS loads. The UPS loads lost power for approximately 12 minutes

during the event.

After Information Notice (IN) 93-26 was issued on April 7, 1993, additional

information was obtained from GE and NMP2. The additional information in

this supplement is intended to assist recipients in determining the

significance of this potential failure mode at their facilities.

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January 31, 1994 Discussion

Niagara Mohawk Power Corporation, the licensee for Nine Mile Point 2 (LER 92-007-00), and Wyle Laboratories (Report No. 42370-RCCB-I) determined

that circuit breaker CB-4 had failed to close because the grease used at the

pivot points inside the breaker had dried out and solidified. When the grease

dried out, the metal-to-metal contact areas experienced increased friction and

eventual gouging. The friction caused the breaker to become increasingly more

difficult to close, until, finally, the breaker would not close at all. The

licensee located all breakers of the same make, model, and year as the one

that failed and scheduled their replacement.

Certain observations were made in the NMP2 analysis relative to these

breakers:

1. The safety function of these breakers is both to open and close

automatically. Normally, the only electrical safety function of a

breaker is its ability to trip. None of the breakers of this type at

Nine Mile Point 2 have failed to trip when required.

2. Due to the nature of the application of these molded-case switches, they

were cycled extensively (approximately 200-400 times). This is more than

a normal molded-case circuit breaker used in a distribution panel.

3. The breakers were in close proximity to the UPS transformers causing

operation above normal ambient conditions, which may or may not have

contributed to the solidification of the grease.

GE has stated that in early 1980 the soap-based and clay-based grease used in

this style molded-case circuit breakers was replaced with a synthetic

lubricant as a product enhancement. However, older molded-case circuit

breakers using the clay-based and soap-based grease may still be in use at

other plants, in similar applications.

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93-26, Supp. 1 January 31, 1994 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

nan K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Mark D. Pratt, NRR

(301) 504-2701 Attachment:

List of Recently Issued NRC Information Notices

~'~IN

93-26, Supp. 1 January 31, 1994 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Odginal fgned by

Brian K.

Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Mark D. Pratt, NRR

(301) 504-2701 Attachment:

List of Recently Issued NRC Information Notices

EELB Concurrence obtained by M.D. Pratt

• EELB:DE:NRR

MDPratt

12/22/93

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12/22/93 DOCUMENT NAME: 93-26SP1.IN

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IN 93-26, Supp. 1 January xx, 1994 This information notice requires no specific action or written response.

If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Mark D. Pratt, NRR

(301) 504-2701 Attachment:

List of Recently Issued NRC Information Notices

EELB Concurrence obtained by M.D. Pratt

• EELB:DE:NRR

MDPratt

12/22/93 D/DE ,

WHodge'V'W

01/12./94 DOCUMENT NAME:

SC/EELB:DE:NRR

EWWeiss

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12/22/93

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C/EELB:DE:NRR

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BKGrime'l

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12/17/93

• RPB: ADM

Tech Ed

12/22/93 I

IN 93-XX

December xx, 1993 This information notice requires no specific action or written response.

If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Mark D. Pratt, NRR

(301) 504-2701 Attachment:

List of Recently Issued NRC Information Notices

(FEELB Concurrence obtained by M.D. Pratt ./A

/Ie/w/Z3 EELB:DE:NRR

MDPrat 4H&y

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Tech Ed

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IN 93-XX

December xx, 1993

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Mark D. Pratt, NRR

(301) 504-2701 Attachment:

List of Recently Issued NRC Information Notices

GEELB Concurrence obtained by

EELB:DE:NRR

SC/EELB:DE:NRR

MDPratt&

EWWeisst)

D/DORS:NRR

C/OGCB: DORS:NRI

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Attaci

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IN 93-26, Supp. 1

January 31, 1994

Page I of I

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Informati0n,

-Date

of

Notice No.

Subject

Issuance

Issued to

94-07

93-85, Rev. 1

Solubility Criteria for

Liquid Effluent Releases

to Sanitary Sewerage Under

the Revised 10 CFR Part 20

Potential Failure of

Long-Term Emergency

Nitrogen Supply for the

Automatic Depressurization

System Valves

Problems with X-Relays

in DB- and DHP-Type

Circuit Breakers Manu- factured by Westinghouse

Potential Failure of

Steam Generator Tubes

with Kinetically Welded

Sleeves

Digital Integrated

Circuit Sockets with

Intermittent Contact

Deficiencies Identified

during Service Water System

Operational Performance

Inspections

Inoperability of General

Electric Magne-Blast

Breaker Because of Mis- alignment of Close-Latch

Spring

Turbine Blade Failures

Caused by Torsional

Excitation from Electrical

System Disturbance

01/28/94

01/28/94

01/20/94

01/19/94

01/14/94

01/11/94

01/07/94

01/07/94

All byproduct material and

fuel cycle licensees with

the exception of licensees

authorized solely for

sealed sources.

All holders of OLs or CPs

for boiling water reactors.

All holders of OLs or CPs

for nuclear power reactors.

All holders of OLs or CPs

for pressurized water

reactors (PWRs).

All NRC licensees except

licensed operators.

All holders of OLs or CPs

for nuclear power reactors.

All holders of OLs or CPs

for nuclear power reactors.

All holders of OLs or CPs

for nuclear power reactors.

94-04

94-03

94-02

OL e Operating License

CP = Construction Permit