Information Notice 1995-19, Failure of Reactor Trip Breaker to Open Because of Cutoff Switch Material Lodged in the Trip Latch Mechanism

Failure of Reactor Trip Breaker to Open Because of Cutoff Switch Material Lodged in the Trip Latch Mechanism

ML031060244
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	03/22/1995
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-95-019, NUDOCS 9503160374
Download: ML031060244 (12)

-e UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 March 22, 1995 NRC INFORMATION

NOTICE 95-19: FAILURE OF REACTOR TRIP BREAKER TO OPEN BECAUSE OF CUTOFF SWITCH MATERIAL LODGED IN THE TRIP LATCH MECHANISM

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 alert addressees

to the possible failure of a circuit breaker to open because of obstruction

by material from a subcomponent

switch. It is expected that recipients

will review this 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 July 14, 1994, during the monthly testing of the logic matrix of the reactor protection

system at St. Lucie, Unit 2, a General Electric (GE)Model AK 2-25 circuit breaker failed to open after operating

correctly

on three previous steps of the surveillance

procedure.

This circuit breaker is one of eight reactor trip circuit breakers in a one-out-of-two

taken twice reactor trip coincidence

logic. Several unsuccessful

attempts were made to open the breaker both electrically

and mechanically

before the licensee isolated the breaker as required by the Technical

Specifications

and shut down the Unit 2 reactor.The investigation

of the problem revealed that a 6-mm-square

[1/4-inch-square]

piece of phenolic material had jammed the circuit breaker trip latch mechanism, preventing

its operation.

This piece of phenolic material had broken off from the breaker cutoff switch (p/n 622 C 505 GI), which is part of the breaker antipump circuitry.

The cutoff switch is mounted in the breaker assembly above the trip latch mechanism (Figure 1). A screw holding the cutoff switch had come loose, allowing two halves of the switch to separate, become misaligned, and break during the previous circuit breaker operation.

The licensee inspected

the remaining

Unit 2 trip circuit breakers as well as the similar motor generator

set output breakers.

No additional

loose screws were found on the cutoff switch mountings.

The licensee has incorporated

the inspection

of the cutoff switch phenolic block and screw into the maintenance

procedures

for Units I and 2. a o ' 6s b 9503160374 PAQ T*tE bo s(A, qf-(otqS I ) 3H at44 I~ C fl

-V., IN 95-19 March 22, 1995 Discussion

On April 6, 1989, GE Switchgear

Operation

issued service advisory letter (SAL)303.0, which dealt with the possibility

that the cutoff switch actuator could crack and break and lead to breaker coil burnout. The text of SAL 303.0 is shown in Attachment

2. Although these cutoff switches had a different failure mode and were installed

on different

breaker models (Models AKR(U) 30s and AK(U) 25-1), the cutoff switch in question was the same part (p/n 622 C 505 GI) as the one that caused the AK2-25 breaker failure at St. Lucie, Unit 2.The majority of the reactor trip breaker failures at power reactors have been caused by problems with relatively

small electrical

subcomponents

in the breaker assembly, rather that the malfunction

of the main breaker mechanism itself. The failure of the cutoff switch in the trip breaker at St Lucie is another example of a subcomponent

failure resulting

in the failure of a trip breaker. The frequency

of reactor trip breaker failures could be reduced if these small component

problems were made less likely by appropriate

inspection

and maintenance.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRP) project manager.Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation

Technical

contacts:

S. Rudisail, Region II S. K. Mitra, NRR (404) 331-5582 (301) 415-2783 M. B. Shymlock, Region II (404) 331-5596 Attachments:

1. Figure 1 2. GE SAL 303.0 3. List of Recently Issued NRC Information

Notices

KJi Attachment

1 IN 95-19 March 22, 1995 FIGURE 1 AK-2 BREAKER FRONT VIEW f CUTOFF SWITCH TX

CONTACT

OR>

PIECE OF CUTOFF SWITCH DROPPED DOWN TO BOlTOM OF THE TRIP LATCH PREVENTING

THE LATCH FROM ACTUATING (CUTOFF SWITCH PIN 622 C 505 Gl)

vJ Attachment

2 IN 95-19 March 22, 1995 SWITCHGEAR

OPERATION SERVICE ADVICE SUBJECT ELECTRICALLY

OPERATED AKR 30S AND AKRU 30S BREAKERS AK 25-1 AND AKU 25-1 BREAKERS CUT OF SWITCH BREAKAGE-- I Ce MAn jnIV n TAB uIjsu SWGR OPER O.ba A1U .JUJ .U_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ I _ _ _ _ _ _ _ _ _ _ _ _ _ I _ _ _ _ _ _ _ _ _Backqround

The function of closing coil when the the Cut Off Switch is to interrupt

the breaker is closed.Problem On electrically

operated AKR(U) 30S and AK(U) 25-1 breakers manufactured

between July 1986 and November 1987 there is a possibility

that the cut off switch actuator may crack and break.If this occurs, the closing coil may be overheated

and burn up when the breaker is closed.Recommended

Action GE recommends

that the cut off switch actuator on all affected breakers be visually checked for cracks at the next regular breaker maintenance

/ inspection.

This includes all AKR(U) 30S breakers with a Breaker Code Date less than P747+ and all AK(U) 25-1 breakers with a Breaker Date Code P548+ through P747+. The Breaker Code Date is on the control voltage nameplate located to the right of the escutcheon

on the breaker frame.Corrective

Action If a broken or cracked cut off switch is found, contact Customer Service for a no-charge

replacement

cut off switch [Part No. 622C505G1]

at: Mary Hockett Customer Service General Electric PO Box 488 Burlington, IA 52601 Phone: (319) 753-8475 8*673-6475 Telecopier:

(319) 753-5479 8*673-6479 Please have Breaker Serial Numbers and Date Codes when you contact us.I_ ,_ _ _ ...z p x PREPARED BY GARY SCHULE II II I I ISSUED BY DON LESNET II II II DATE I bUFtURtULb

IISSUE DATED 4-06-89 0 (NEW)IIOF 1 Attachment

3 IN 95-19 March 22, 1995 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 95-18 95-17 95-16 95-15 95-14 Potential

Pressure-Locking

of Safety-Related

Power-Operated Gate Valves Reactor Vessel Top Guide and Core Plate Cracking Vibration

Caused by Increased

Recirculation

Flow in a Boiling Water Reactor Inadequate

Logic Testing of Safety-Related

Circuits Susceptibility

of Con-tainment Sump Recircula- tion Gate Valves to Pressure Locking Potential

for Data Collection

Equipment

to Affect Protection

System Performance

Potentially

Nonconforming

Fasteners

Supplied by A&G Engineering

II, Inc.Failure of Condensate

Piping Because of Erosion/Corrosion

at a Flow-Straightening

Device Potential

for Loss of Automatic

Engineered

Safety Features Actuation 03/15/95 03/10/95 03/09/95 03/07/95 02/28/95 02/24/95 02/21/95 02/24/95 02/10/95 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs 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 nuclear power reactors.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.All holders of OLs or CPs for nuclear power reactors.95-13 95-12 95-11 95-10 Supp. 1 OL = Operating

License CP = Construction

Permit

IN 95-19 March 22, 1995 Discussion

On April 6, 1989, GE Switchgear

Operation

issued service advisory letter (SAL)303.0, which dealt with the possibility

that the cutoff switch actuator could crack and break and lead to breaker coil burnout. The text of SAL 303.0 is shown in Attachment

2. Although these cutoff switches had a different failure mode and were installed

on different

breaker models (Models AKR(U) 30s and AK(U) 25-1), the cutoff switch in question was the same part (p/n 622 C 505 Gi) as the one that caused the AK2-25 breaker failure at St. Lucie, Unit 2.The majority of the reactor trip breaker failures at power reactors have been caused by problems with relatively

small electrical

subcomponents

in the breaker assembly, rather that the malfunction

of the main breaker mechanism itself. The failure of the cutoff switch in the trip breaker at St Lucie is another example of a subcomponent

failure resulting

in the failure of a trip breaker. The frequency

of reactor trip breaker failures could be reduced if these small component

problems were made less likely by appropriate

inspection

and maintenance.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Gri fbyiatlI K. rmes Division of Project Support Office of Nuclear Reactor Regulation

Technical

contacts:

S. Rudisail, Region II S. K. Mitra, NRR (404) 331-5582 (301) 415-2783 M. B. Shymlock, Region II (404) 331-5596 Attachments:

1. Figure 1 2. GE SAL 303.0 3. List of Recently Issued NRC Information

Notices DOCUMENT NAME: S:\DOPS SEC\95-19.IN

• See previous concurrence

OECB:DOPS:NRR*

RPB:ADM EELB:DE C/EELB:DE DCKirkpatrick

l BCalure, Tech Ed* SKMitra* CEBerlinger*

12/22/94 l 12/28/94 01/23/95 01/23/95 RII (via e-mail) RII (via e-mail) SC/OECB:DOPS:NRR

OECB:DOPS:NRR

SRudisail*

MBShymlok*

EFGoodwin*

RJKiessel*

01/25/95 01/25/95 Z 01/26/95 02/01/95 C/OECB:DOPS:NRR

D/J4* 7 =AEChaffee*

03/11/95 03// /95 OFFICIAL RECORD COPY

v~~IN 95-XX March xx, 1995 Discussion

On April 6, 1989, GE Switchgear

Operation

issued service advisory letter (SAL)303.0, which dealt with the possibility

that the cutoff switch actuator could crack and break and lead to breaker coil burnout. The text of SAL 303.0 is shown in Attachment

2. Although these cutoff switches had a different failure mode and were installed

on different

breaker models (Models AKR(U) 30s and AK(U) 25-1), the cutoff switch in question was the same part (p/n 622 C 505 Gl) as the one that caused the AK2-25 breaker failure at St. Lucie, Unit 2.The majority of the reactor trip breaker failures at power reactors have been caused by problems with relatively

small electrical

subcomponents

in the breaker assembly, rather that the malfunction

of the main breaker mechanism itself. The failure of the cutoff switch in the trip breaker at St Lucie is another example of a subcomponent

failure resulting

in the failure of a trip breaker. It follows that the frequency

of reactor trip breaker failures could be significantly

reduced if these small component

problems could be eliminated

by careful inspection

and maintenance.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation

Technical

contacts: S. Rudisail, Region II (404) 331-5582 S. K. Mitra, NRR (301) 504-2783 M. B. Shymlock, Region II (404) 331-5596 Attachments:

1. Figure 1 2. GE SAL 303.0 3. List of Recently Issued NRC Information

Notices DOCUMENT NAMF: s!\nlfPS SFC\RRFAKER

• See nrev'ious concurrence

OECB:DOPS:NRR*

RPB:ADM EELB:DE C/EELB:DE DCKirkpatrick

BCalure, Tech Ed* SKMitra* CEBerlinger*

12/22/94 12/28/94 01/23/95 01/23/95 RII (via e-mail) RII (via e-mail) SC/OECB:DOPS:NRR

OECB:DOPS:NRR

SRudisail*

MBShymlok*

EFGoodwin*

RJKiessel*

01/25/95 01/25/95 01/26/95 02/01/95 C/OECB:DOPS:NRR

D/DOPS:NRR

AEChaffee*

BKGrimes 03/11/95 0 / j95_OFF IC IAL RECORD COPY

IN 95-xx March xx, 1995 Discussion

On April 6, 1989, GE Switchgear

Operation

issued service advisory letter (SAL)303.0, which dealt with the possibility

that the cutoff switch actuator could crack and break and lead to breaker coil burnout. The text of SAL 303.0 is shown in Attachment

2. Although these cutoff switches had a different failure mode and were installed

on different

breaker models (Models AKR(U) 30s and AK(U) 25-1), the cutoff switch in question was the same part (p/n 622 C 505 GI) as the one that caused the AK2-25 breaker failure at St. Lucie, Unit 2.The majority of the reactor trip breaker failures at power reactors have been caused by problems with relatively

small electrical

subcomponents

in the breaker assembly, rather that the malfunction

of the main breaker mechanism itself. The failure of the cutoff switch in the trip breaker at St Lucie is another example of a subcomponent

failure resulting

in the failure of a trip breaker. It follows that the frequency

of reactor trip breaker failures could be significantly

reduced if these small component

problems could be eliminated

by careful inspection

and maintenance.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation

Technical

contacts: S. Rudisail, Region II (404) 331-5582 S. K. Mitra, NRR (301) 504-2783 M. B. Shymlock, Region II (404) 331-5596 Attachments:

1. Figure 1 2. GE SAL 303.0 3. List of Recently Issued NRC nnrlMFrNT

NAME- n-\nN\RRFAKFR

Information

Notices*See nrevious concurrence

vvVl r L. v \ --__ ._ .. ____.~. -.._........

__OECB:DOPS:NRR*

RPB:ADM* EELB:DE* C/EELB:DE*

DCKirkpatrick

BCalure, Tech Ed SKMitra CEBerlinger

12/22/94 12/28/94 01/23/95 01/23/95 RII* (via e-mail) RII* (via e-mail) SC/OECB:DOPS:NRR*

SRudisail

MBShymlok

EFGoodwin 01/25/95 01/25/95 01/26/95 OECB:DOPS:NRR*

C BD N D/DOPS:NRR

RJKiessel

AEChlree P BKGrimes 02/01/95 /11 /95 01/ /95 OFFICIAL RECORD COPY

IN 95-xx January xx, 1995 Discussion

On April 6, 1989, GE Switchgear

Operation

issued service advisory letter (SAL)303.0, which dealt with the possibility

that the cutoff switch actuator could crack and break and lead to breaker coil burnout. A copy of SAL 303.0 is attached.

Although these cutoff switches had a different

failure mode and were installed

on different

breaker models (Models AKR(U) 30s and AK(U) 25-1), the cutoff switch in question was the same part (p/n 622 C 505 GI) as the one that caused the AK2-25 breaker failure at St. Lucie, Unit 2.The majority of the reactor trip breaker failures at power reactors have been caused by problems with relatively

small electrical

subcomponents

in the breaker assembly, rather that the malfunction

of the main breaker mechanism itself. The failure of the cutoff switch in the trip breaker at St Lucie is another example of a subcomponent

failure resulting

in the failure of a trip breaker. It follows that the frequency

of reactor trip breaker failures could be significantly

reduced if these small component

problems could be eliminated

by careful inspection

and maintenance.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation

Technical

contacts: S. Rudisail, Region II (404) 331-5582 S. K.(301)Mitra, NRR 504-2783 M. B. Shymlock, Region II (404) 331-5596 Attachments:

1. Figure 1 2. GE SAL 303.0 3. List of Recently Issued NRC nfnrilMrKT

IAMEM. r- \n N\RnFAVFR Information

Notices*SeP nrevious concurrence

UV%111L-1%

I 111ru-19- U. vuvuW-Xl ---re OECB:DOPS:NRR*

RPB:ADM* EELB:DE* C/EELB:DE*

DCKirkpatrick

BCalure, Tech Ed SKMitra CEBerlinger

12/22/94 J 12/28/94 01/23/95 _ 01/23/95 RII* (via e-mail) RII* (via e-mail) SC/OECB:DOPS:NRR*

SRudisail

MBShymlok

EFGoodwin 01/25/95 01/25/95 01/26/95 OECB:DOPS:NRR

C/OECB:DOPS:NRR

D/DOPS:NRR

=RJKiesse AEChaffee

BKGrimes*y /95 01/ /95 01/ /95 OFFICIAL RECORD COPY

IN 95-xx January xx, 1995 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Project Support Office of Nuclear Reactor Regulation

Technical

contacts: S. Rudisail, Region II (404) 331-5582 M. B. Shymlock, Region II (404) 331-5596 S. K. Mitra, NRR (301) 504-2783 Attachments:

1. Figure 1 2. GE SAL 303.0 3. List of Recently MV tf la Issued NRC Information

Notices OECB:DOPS:NRR*

l RPB:ADM* EELB:DE C/EELB:DE

>DCKirkpatrick

BCalure ,Tech Ed SKMitra CEBerlinger

'l 12/22/94 12/28/94 1/Z3/95 1/Z/95lREG II I i^ REG II SC/OECB:DOPS:NRR

lSRudisail

MBShymlok~

-IEFGoodwin

0OIi1/95 J 01f)/95 01_ 9_5 OECB:DOPS:NRR

C/OECB:DOPS:NRR

D/DOPS:NRR

RJKiessel

AEChaffee

BKGrimes* 01/ /95 01/ /95 pc/ /95*See previous concurrences

From: Donald C. Kirkpatrick (DCK1)To: SBR Date: Wednesday, January 25, 1995 10:43 am Subject: CONCURNCE

W IN:FAILURE

OF RX TRIP BREAKR Steve: The attached file contains your proposed IN on the failure of the reactor trip breaker due to foreign material in the latch. Brian Grimes decided that it should be issued after all. We added some history on previous problems with the cutoff switch that was the source of the jamming material.Please review it, concur if possible and pass it on to Shymlock.

Pleace call me at (301) 504-1849 if you need anything else on this.Thanks, Don Kirkpatrick, OECB Files: G:\DON\BREAKER

From: Steven B. Rudisail (SBR)To: AT1:HMS1:HMS2:WN4:DCK1 Date: Wednesday, January 25, 1995 3:03 pm Subject: CONCURNCE

W IN:FAILURE

OF RX TRIP BREAKR Milton Shymlock and I have reviewed the draft notice and we both concur.CC: MBS

1. Contents of GE Service Advisory Letter 303.0 2. List of Recently Issued NRC Information

Notices OECB:DOPS:NRR

RPB:ADM EELB:DE C/EELB:DE DCKirkpatric

k , ' 4 9,4 Tech Ed SKMitra CEBerlinger

12/2/94 12b??/94 01/ 95 REG II REG II SC/OECB:DOPS

NRR SRudisail

MBShymlok

EFGoodwin 01/ /95 01/ /95 01/ /95 OECB:DOPS:NRR

C/OECB:DOPS:NRR

D/DOPS:NRR

RJKiessel

AEChaffee

BKGrimes 01/ /95 01/ /95 01/ /95 2Z