Information Notice 1994-54, Failures of General Electric Magne-Blast Circuit Breakers to Latch Closed

Failures of General Electric Magne-Blast Circuit Breakers to Latch Closed

ML031060555
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:	08/01/1994
From:	Grimes B K Office of Nuclear Reactor Regulation
To:
References
IN-94-054, NUDOCS 9407270127
Download: ML031060555 (15)

UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 August 1, 1994 NRC INFORMATION

NOTICE 94-54: FAILURES OF GENERAL ELECTRIC MAGNE-BLAST

CIRCUIT BREAKERS TO LATCH CLOSED

Addressees

All holders of operating

licenses or construction

permits for nuclear power reactors.PurDose The U.S. Nuclear Regulatory

Commission (NRC) is issuing this information

notice to alert addressees

to a condition

in which certain General Electric (GE) medium-voltage

Magne-Blast

circuit breakers may begin to randomly fail to latch closed. 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

The Maine Yankee Atomic Power Station (Maine Yankee) and the Millstone

Nuclear Power Station (Millstone)

have recently experienced

failures of safety-related

GE Magne-Blast

4160-Vac circuit breakers to latch closed (also called "going trip-free").

Failures occurred during post-overhaul, preoperational, and in-service

surveillance

testing. At Maine Yankee, failures occurred shortly after an overhaul of the breakers, during troubleshooting

of an indirectly

related problem with limit switches.

The affected breakers have failed to latch on a random basis during up to about two-thirds

of attempted

closures, both electrically

and manually.

At both plants, the affected breakers were among those recently overhauled

by the GE Apparatus

Service Division of Philadelphia, with quality assurance

coverage provided by GE Nuclear Energy (NE) Power Delivery Services (PDS) of King of Prussia, Pennsylvania.

Failure analysis, inspection, and testing of one of the affected breakers from Maine Yankee were performed

at the GE Apparatus

Service Division under the direction of GE NE PDS and the design engineer from the breaker manufacturer, GE Specialty

Breaker Plant. The results were consistent

with onsite testing at both Millstone

and Maine Yankee. The failure analysis activities, observed by NRC and licensee representatives, identified

the primary failure mode, apparent principal

root causes, and the most effective

remedies.9407270127 PmR 2 -O5M qq9 o(up&LB} b gl~lIX v\

IN 94-54-August 1, 1994 Discussion

The breaker models considered

to be potentially

affected at the present time include (1) Type AM-4.16-350-1H

and (2) Type AM-4.16-250-6, -7, -8, or -9HB.GE is currently

evaluating

other Magne-Blast

models for potential susceptibility.

Among these models, only breakers equipped with one prop reset spring (prop spring), and in which all "Tuf-Loc" (Teflon-coated

fiberglass)

bushings (especially

the prop bushings)

have been replaced with aluminum-bronze

bushings, have recently experienced

unreliable

latching.However, it should be noted that this failure ultimately

results from a combination

of contributing

factors and not all breakers of the potentially

affected type and configuration

are prone to failure. In addition, there have been a few instances (although

not recently)

of one-prop spring breakers with Tuf-Loc prop bushings that have failed to latch due to other unsatisfactory

conditions

within the breaker such as excessive

wear, hardened or insufficient

lubrication, and/or being severely out of adjustment.

No failures are known to GE or the NRC to occur in breakers equipped with two prop springs (included as original equipment

since 1968, or added during maintenance

or repair). The failure analysis testing appeared to confirm the GE position that breakers with two prop springs should not experience

this problem. The details of the failure mode are discussed

in Attachment

1 to this information

notice.Attachment

2 shows the prop springs.It should be noted that, depending

on the severity of the various contributing

conditions, the onset of failure to latch reliably in these breakers may vary, and a breaker that has successfully

passed rigorous post-maintenance

testing and further receipt inspection

and preoperational

testing may subsequently

start failing to latch reliably in service. In recent instances, failures to latch have begun to occur after about 35-50 operations (cycles) following overhaul or repair of the operating

mechanism.

Once started, the failure frequency

has been observed during testing, to vary from 1 failure to latch in as many as 50 consecutive

operations

to 16 failures in 24 attempts.

The operating

characteristics

of a given breaker (in particular, adequacy and consistency

of prop action as explained

in Attachment

1) can indicate the likelihood

of unreliable

latching.

According

to GE, the desired prop action positions

the prop fully forward against its stop, thus providing

maximum engagement

under the prop pin (called prop wipe). However, affected breakers that start (or are likely to start) failing to latch reliably typically exhibit inconsistent (and often less than the design minimum) prop wipe even when they do latch.The NRC and licensees

have expressed

concerns regarding

increased

suscepti-bility to unwanted tripping with less than minimum design prop wipe caused by vibration

or shock (e.g., during a seismic event). The Magne-Blast

design engineer has stated that because of the geometry and magnitude

of forces acting on the prop, once the mechanism

has successfully

latched (even if only barely), it would be extremely

unlikely for the shocks or vibration

associated

with seismic events to cause the prop to move backwards

and olut from under the prop pin. Nevertheless, a breaker that is latched, but with less than the design minimum prop wipe, is not in a condition

for which it was analyzed or in which it was tested during seismic qualification.

IN 94-54 August 1, 1994 Normal prop wipe can be confirmed

with the breaker in its cubicle and closed (in test position if necessary)

in most installations

by visual inspection (using an inspection

mirror and light) without having to get too close to energized

components

or hazardous

mechanism

parts if the switchgear

cabinet door can be opened with appropriate

safety precautions.

Pending issuance of a service advice letter (SAL) by the manufacturer

on this problem or a safety communication

by GE NE, Attachment

2 illustrates

an inspection

hole in the right side of the mechanism

frame through which the prop and prop pin position may be viewed. While the fully forward prop position (to the stop) is the desired condition (maximum wipe), the absence of failures to latch along with consistent

and greater than minimum allowed prop wipe is, according

to GE, indicative

of continued

reliable latching.

However, because minimum prop wipe is not a published

design specification, and because certain other factors (e.g., opening spring adjustment)

may influence

latching reliability, GE has requested

that any licensee experiencing

Magne-Blast

breaker latching problems or noticing changed, inconsistent

or apparently

abnormally

low prop wipe, particularly

following

overhaul or repair including

prop bushing replacement, contact GE NE PDS at (610) 992-6049.Pending installation

of a second prop spring in affected breakers, Maine Yankee has shifted, to the extent possible, its available

dual prop spring breakers to locations

where operability

requires assured latching reliability

for closure or reclosure

during a design-basis

event. For the remaining potentially

affected breakers, Maine Yankee is planning expedited

inspections

with the assistance

of GE NE PDS to aid in its operability

determinations.

Related Generic Communications

Information

Notice 84-29, "General Electric Magne-Blast

Circuit Breaker Problems," dated April 29, 1984.Information

Notice 90-41, "Potential

Failure of General Electric Magne-Blast

Circuit Breakers and AK Circuit Breakers," dated June 12, 1990.Information

Notice 93-91, "Misadjustment

Between General Electric 4.16-KY Circuit Breakers and Their Associated

Cubicles," dated December 3, 1993.Information

Notice 94-02, "Inoperability

of General Electric Magne-Blast

Breaker Because of Misalignment

of Close-Latch

Spring," dated January 7, 1994.

IN 94-54: August 1, 1994 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 Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Stephen Alexander, NRR (301) 504-2995 Kamalakar

Naidu, NRR Sikindra Mitra, NRR (301) 504-2980 (301) 504-2783 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices 47 g ^d AnJ-L

Attachment

1 IN 94-54 August 1, 1994 DETAILS OF THE FAILURE MODE AND CONTRIBUTING

FACTORS The cause of the failures to latch cited in the body of the Information

Notice is related to a component

of the Type ML-13 breaker operating

mechanism

called the prop (see Attachment

2). The breaker will fail to latch closed when the prop does not travel forward fast enough (relative

to the motion of the closing linkage) to be in the proper position under the prop pin of the closing linkage as it rises above then descends onto the prop during the closing cycle (whether manually or electrically

initiated).

Absent a trip condition

upon closing, the prop is permitted (by the rotation of the main cam) to be pulled forward under the prop pin by the prop reset spring (or springs when two are fitted). If the slower speed of the prop relative to the pin is such that the pin passes down in front of the prop instead of landing on top of it (called latching)

as it is supposed to, the linkage will"collapse" causing the moving contact arms to immediately

drop down to the open position.

This condition

or action is also called the trip-free condition

because it occurs in the same manner as if a trip signal were present at the breaker tripping mechanism

when the breaker attempts to close, thus preventing

the prop from moving forward and latching.According

to GE, and as apparently

confirmed

by testing, several conditions

must be present to render a given breaker susceptible

to this failure mode.Most fundamental

are the individual

breaker model and configuration, mechanism type, and vintage. Within these constraints, certain modifications

or upgrades that have (or have not) been performed

on a given breaker influence its susceptibility.

Finally, the condition

of the breaker mechanism

in terms of age and type of moving parts, wear, lubrication, and adjustment

can ultimately

be the determining

factor with regard to latching reliability.

Due to their particular

combination

of operating (opening and closing) spring configurations, all 4.16-kilovolt (Kv)-rated, vertical-lift, air-magnetic (Magne-Blast)

breakers of 350-million

volt-ampere (MVA) interrupting

rating (Type AM-4.16-350-1H)

that are fitted with only one prop spring are considered

by GE to be potentially

affected.

Also potentially

affected, owing also to their particular

operating

spring configurations, are those 4.16-Kv, 250-MVA-rated Magne-Blast

breakers with one prop spring that have a 78-kilo-ampere (kA) close-latch

rating (called a "high momentary" rating), which includes Models AM-4.16-250-6, -7, -8, or -9HB (the "H" suffix indicates

the ML-13 type mechanism

and the "B" indicates

the high momentary

rating).Within this population, the major factor determining

susceptibility

is the number of prop springs installed.

With one anomalous

exception (a breaker suspected

of being grossly out of adjustment), only breakers with one prop spring have thus far been reported to experience

unreliable

latching.Breakers of these models built before about 1968 were originally

fitted at the factory with a single prop spring. After this time, breakers with close and latch ratings of 77 Ka or 78 Ka were factory fitted with two prop springs, in order, according

to GE, to make the breakers less sensitive

to fit and adjustment

tolerances

and to facilitate

factory setup. The failure analysis testing indicated

that breakers built with or modified subsequently

to add a second (upper) prop spring, and that are not otherwise

in severely out of tolerance

condition, should not be susceptible

to this failure mode.

Attachment

1: IN 94-54 August 1, 1994 The breaker manufacturer, in GE Service Advice Letter (SAL) No. 073-348.1, issued in December 1990, recommended

replacement

of the main (lower) prop spring with an improved spring (called the "gold" prop spring because of the color of its cadmium plating).

NRC Information

Notice 90-41, "Potential

Failure of General Electric Magne-Blast

Circuit Breakers and AK Circuit Breakers," also addressed

this problem. The gold prop spring has been fitted in breakers built since 1971, due to fatigue failures reported in the original spring. Although SAL 073-348.1 did describe the dual prop spring configuration, it did not address the addition of a second prop spring. See Attachment

2.Recent breaker overhauls/repairs

that included replacement

of the Tuf-Loc (Teflon-coated

fiberglass)

prop bushings with aluminum-bronze

prop bushings, in conjunction

with cleaning and relubrication

of the closing linkage and renewal of worn parts have not been demonstrated

conclusively

to be the sole cause of the recently reported failures to latch. However, they appear to have been the common precipitating

events. In breakers of the affected models with one prop spring that have had all the Tuf-Loc bushings (except for the prop bushings)

replaced with aluminum-bronze, the recently reported failures to latch have begun to occur after about 35-50 operations (cycles) after completion

of overhaul or repair that included replacement

of the Tuf-Loc prop bushings with aluminum-bronze.

Since 1975, these breakers have been fitted with aluminum-bronze

sleeve bearings or bushings in their mechanisms (except for the prop bushings)

for improved wear characteristics.

Many of the older Magne-Blast

breakers, in accordance

with GE SAL 073-318.1 (and .1A), issued in 1977, and 318.2, issued in 1979, have had their original Tuf-Loc bushings replaced with the aluminum-bronze

bushings.

IE Information

Notice 84-29, "GE Magne-Blast

Circuit Breaker Problems," also addressed

this issue. The factory bushing replacement

kits, supplied under catalog no. 0156C9403G001, did not include replacement

bushings for the prop. Hence, most prop bushing replacements

have been performed

only recently.When other conditions

in a breaker are conducive

to marginal latching, it appears that the new bushings, in conjunction

with reduced friction in the closing linkage from the overhaul, cleaning and new lubricant, may shift the force and speed balance in the mechanism.

The shift can be sufficient

to speed up the motion of the closing linkage and prop pin relative to the prop (which also may actually be slightly retarded)

beyond design margins. Under these conditions, a single prop spring can no longer move the prop forward fast enough to latch reliably, or if it does latch, to ensure the desired prop wipe. Where the second prop spring has been installed

in conjunction

with the mechanism

overhaul, failure to latch reliably in the manner described

herein has not been reported, and according

to GE, as confirmed

by testing, would not be expected to occur. Disassembly

and detailed inspection

of the Maine Yankee breaker operating

mechanism

after testing revealed no additional

significant

factors contributing

to the failures to latch experienced

by the test breaker.Therefore, the test results appear to have confirmed

the factors to which close-latch

reliability

is most sensitive.

Attachment

2 1, IN 94-54 August 1, 1994 Page 1 of I MAGNE-BLAST

OPERATING

MECHANISM

PROP DIAGRAMS 1.2.3.4.5.5A.6.7.8.9.10.11.12.13.14.15.16.17.Handle Trip Coil Support Trip Coil Trip Armature PROP SPRING SECOND PROP SPRING (if fitted)Cam Follower Roller Trip Shaft Trip Latch Trip Latch Roller Roller Support Crank Shaft Cranks PROP PIN PROP Drive Shaft Cam PROP BUSHING FRONT OF BREAKER Figure 1 (Adapted From Figure 7 of GE Instruction

Book GEI-88761)

Figure 2: Right Side View of ML-13 Operating

Mechanism (From Figure 4 of GE Instruction

Book GEI-88761)

Attachment

3' IN 94-54 August 1, 1994 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 91-45, Supp. 1 Possible Malfunction

of Westinghouse

ARD, BFD, and NBFD Relays, and A200 DC and DPC 250 Magnetic Contactors

07/29/94 All holders of OLs or CPs for nuclear power reactors.94-42, Supp. 1 Cracking in the Lower Region of the Core Shroud in Boiling-Water

Reactors 07/19/94 All holders for boiling (BWRs).of OLs or CPs water reactors 94-53 94-52 94-51 94-50 94-49 Hydrogen Gas Burn Inside Pressurizer

During Welding Inadvertent

Containment

Spray and Reactor Vessel Draindown

at Millstone Unit 1 Inappropriate

Greasing of Double Shielded Motor Bearings Failure of General Electric Contactors

to Pull in at the Required Voltage Failure of Torque Switch Roll Pins Snubber Lubricant Degradation

in High-Temperature

Environments

Unanticipated

and Unin-tended Movement of Fuel Assemblies

and other Components

due to Improper Operation

of Refueling Equipment 07/18/94 07/15/94 07/15/94 07/14/94 07/06/94 06/30/94 06/28/94 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.All holders of OLs or CPs for nuclear power reactors.94-48 94-13, Supp. 1 OL = Operating

License CP = Construction

Permit

IN 94-54 August 1, 1994 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.orig /s/'d by CIGrimes/for

Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Stephen Alexander, NRR (301) 504-2995 Kamalakar

Naidu, NRR (301) 504-2980 Sikindra Mitra, (301) 504-2783 NRR Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices*SEE PREVIOUS VIB:DRIL SAlexander*

05/19/94 CONCURRENCE

VIB:DRIL KNaidu*04/14/94 SC/VIB:DRIL

GCwal ina*05/19/94 TECHED MMejac*04/18/94 C/VIB:DRIL:NRR

LNorrholm*

05/24/94 D/DRIL:NRR

CERossi*05/27/94 EELB:DE:NRR

SMitra*07/06/94 C/EELB:DE:NRR

CBerlinger*

07/11/94 OGCB:DORS:NRR

PWen*07/13/94 AC/OGCB:DORS:NRR

ELDoolittle*

07/14/94 D/:DORS:NRR

BKGrimes(Y-

1 07D OT/94 NAM DOCUMENT NAME: OFFICIAL RECORD COPY 94-54. IN NOTE: The PMs for Maine Yankee (E. Trottier)

and Millstone-1 (J. Andersen)have been informed of the development

of this information

notice, and their comments have been incorporated.

Steve Alexander

of the Vender Inspection

Branch has the technical

accuracy of this information

notice.been incorporated.

consulted

with GE on GE's comments have Peter Wen, 7/13/94 IN 94-XX July 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 one of the technical

contacts 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

contacts:

Stephen Alexander, NRR (301) 504-2995 Kamalakar

Naidu, NRR Sikindra Mitra, NRR (301) 504-2980 (301) 504-2783 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices*SEE PREVIOUS VIB:DRIL SAlexander*

05/19/94 CONCURRENCE

VIB:DRIL KNaidu*04/14/94 SC/VIB:DRIL

GCwal ina*05/19/94 TECHED MMejac*04/18/94 C/VIB:DRIL:NRR

LNorrholm*

05/24/94 D/DRIL:NRR

CERossi*05/27/94 AO/ :DORS:NRR E 4 ff^1ttl e 07/" /4 EELB:DE:NRR

SMitra*07/06/94 C/EELB:DE:NRR

CBerlinger*

07/11/94 OGCB: QRS:NRR PWen tV\1 07/13 /94 D/:DORS:NRR

BKGrimes 07/ /94 4 DOCUMENT NAME: GEMAGNET.IN

OFFICIAL RECORD COPY NOTE: The PMs for Maine Yankee (E. Trottier)

and Millstone-I (J. Andersen)have been informed of the development

of this information

notice, and their comments have been incorporated.

Steve Alexander

of the Vender Inspection

Branch has consulted

with GE on the technical

accuracy of this information

notice. GE's comments have been incorporated.

Peter Wen, 7/13/94 IN 94-XX July XX, 1994 Normal prop wipe can be confirmed

with the breaker in its cubicle and closed (in test position if necessary)

in most installations

by visual inspection (using an inspection

mirror and light) without having to get too close to energized

components

or hazardous

mechanism

parts if the switchgear

cabinet door can be opened with appropriate

safety precautions.

Pending issuance of a service advice letter (SAL) by the manufacturer

on this problem or a safety communication

by GE NE, Attachment

2 illustrates

an inspection

hole in the right side of the mechanism

frame through which the prop and prop pin position may be viewed. While the fully forward prop position (to the stop) is the desired condition (maximum wipe), the absence of failures to latch along with consistent

and greater than minimum allowed prop wipe is, according

to GE, indicative

of continued

reliable latching.

However, because minimum prop wipe is not a published

design specification, and because certain other factors (e.g., opening spring adjustment)

may influence

latching reliability, GE has requested

that any licensee experiencing

Magne-Blast

breaker latching problems or noticing changed, inconsistent

or apparently

abnormally

low prop wipe, particularly

following

overhaul or repair including

prop bushing replacement, contact GE NE PDS at 610-992-6049.

Pending installation

of a second prop spring in affected breakers, Maine Yankee has shifted, to the extent possible, its available

dual prop spring breakers to locations

where operability

requires assured latching reliability

for closure or reclosure

during a design-basis

event. For the remaining potentially

affected breakers, Maine Yankee is planning expedited

inspections

with the assistance

of GE NE PDS to aid in its operability

determinations.

NRC Information

Notice 94-XX, issued May XX, 1994, discusses

other recently identified

problems impacting

Magne-Blast

operability, related to defective and improperly

installed

GE CR2940 limit switches.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.ORIG /S/'D BY BKGRIMES Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Stephen Alexander, NRR Kamalakar

Naidu, NRR (301) 504-2995 (301) 504-2980 Sikindra Mitra, NRR (301) 504-2783 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices VIB:DRIL VIB:DRIL SC/VIB:DRIL

SAlexander*

KNaidu* GCwalina*05/19/94 04/14/94 05/19/94 C/VIB:DRIL:NRR

D/DRIL:NRR

EELB:DE(PR, 1 LNorrholm*

CERossi* Smitya afb'05/24/94 05/27/94 cuff /94 OGCB:DORS:NRR

AC/OGCB:DORS:NRR

D7:DORS:NRR

PWen BKGrimes 07/ /94 07/ /94 07/ /94 OFFICIAL RECORD COPY DOCUMENT NAME: I*See previous concurrence

TECHED MMejac*04/18/94 C/EELB:DE:N

f )Cjerlinger

OV/tt/94 MAGNE3AT.GE

IN 94-XX May XX, 1994 Normal prop wi can be confirmed

with the breaker in its cubicle and closed (in test position if necessary)

in most installations

by visual inspection (using an inspectio

mirror and light) without having to get too close to energized

components

r hazardous

mechanism

parts if the switchgear

cabinet door can be opened wit appropriate

safety precautions.

Pending issuance of a service advice letter (SAL) by the manufacturer

on this problem or a safety communication

by GE NE, Attchment

2 illustrates

an inspection

hole in the right side of the mechanism

ame through which the prop and prop pin position may be viewed. While the fully forward prop position (to the stop) is the desired condition (maximum wipe), the absence of failures to latch along with consistent

and greater than minim allowed prop wipe is, according

to GE, indicative

of continued

reliable la thing. However, because minimum prop wipe is not a published

design specificatio, and because certain other factors (e.g., opening spring adjustment)

may i'hluence

latching reliability, GE has requested

that any licensee experiencing

14 gne-Blast

breaker latching problems or noticing changed, inconsistent

or appare tly abnormally

low prop wipe, particularly

following

overhaul or repair in uding prop bushing replacement, contact GE NE PDS at 610-992-6049.

Pending installation

of a second prop sprin in affected breakers, Maine Yankee has shifted, to the extent possible, its aailable dual prop spring breakers to locations

where operability

requires assured latching reliability

for closure or reclosure

during a design-basis

event. For the remaining potentially

affected breakers, Maine Yankee is plannin expedited

inspections

with the assistance

of GE NE PDS to aid in its operabilMty

determinations.

NRC Information

Notice 94-XX, issued May XX, 1994, discusles

other recently identified

problems impacting

Magne-Blast

operability, rela ed to defective and improperly

installed

GE CR2940 limit switches.This information

notice requires no specific action or w *tten response.If you have any questions

about the information

in this notice, lease contact one of the technical

contacts listed below or the appropriate

Of ce of Nuclear Reactor Regulation (NRR) project manager.ORIG /S/'D BY BKGRIMES Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Stephen Alexander, NRR Kamalakar

Naidu, NRR (301) 504-2995 (301) 504-2980 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices VIB:DRIL VIB:DRIL SC/VIB:DRIL

SAlexander*

KNaidu* GCwalina*05/19/94 04/14/94 05/19/94 C/VI BDRIL:NRR

D/D I *N ChftA EELB:DE:NRR

LN I film SMitra'05JK 1 /94 05/17g 4\ 05/ /94 OGCB:DORS:NRR

AC/OGCB:DORS

NRR D/:DORS:NRR

PWen AJKugler BKGrimes 05/ /94 05/ /94 05/ /94 OFFICIAL RECORD COPY DOCUMENT NAME: I*See previous TECHED MMeJac*04/18/94 C/EELB:DE:NRF

CBerlinger

05/ /94 concurrence

MAGNE3AT.GE

IN 94-XX May XX, 1994 Normal prop wipe can be confirmed

with the breaker in its cubicle and closed (in test position if necessary)

in most installations

by visual inspection (using an inspection

mirror and light) without having to get too close to energized

components

or hazardous

mechanism

parts if the switchgear

cabinet can be opened with appropriate

safety precautions.

Pending issuance of a serv' advice letter (SAL) by the manufacturer

on this problem or a safety communic ion by GE NE, Attachment

2 illustrates

an inspection

hole in the right side the mechanism

frame through which the prop and prop pin position may be viewed. hile the fully forward prop position (to the stop) is the desired condition

aximum wipe), the absence of failures to latch along with consistent

and grea than minimum allowed prop wipe is, according

to GE, indicative

of continue reliable latching.

However, because minimum prop wipe is not a published

desig specification, and because certain other factors (e.g., opening spring adjus ent) may influence

latching reliability, GE has requested

that any licensee e eriencing

Magne-Blast

breaker latching problems or noticing changed, inconsiste

or apparently

abnormally

low prop wipe, particularly

following

overhaul o repair including

prop bushing replacement, contact GE NE PDS at 215-992-6049.

Pending installation

of a secon rop spring in affected breakers, Maine Yankee has shifted to the extent possibe, its available

dual prop spring breakers to locations

where operability

quires assured latching reliability

for closure or reclosure

during a design-b is event. For the remaining potentially

affected breakers, Maine Yankee planning expedited

inspections

with the assistance

of GE NE PDS to aid in it operability

determinations.

NRC Information

Notice 94-XX, issued May XX, 19 , discusses

other recently identified

problems impacting

Magne-Blast

operab ity, related to defective and improperly

installed

GE CR2940 limit switches.This information

notice requires no specific ac ion or written response.If you have any questions

about the information

in th notice, please contact one of the technical

contacts listed below or the appro late Office of Nuclear Reactor Regulation (NRR) project manager.ORIG /S/'D BY BKGRIMES Brian K. Grimes, Directo Division of Operating

Reac or Support Office of Nuclear Reactor Regulation

Technical

contacts:

Stephen Alexander, NRR Kamalakar

Naidu, NRR (301) 504-2995 (301) 504-2980 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices VIB:DRIL VIB:DRIL SC V :DRIL TECHED S~lexanderl'J

K &aicu , G & S1na MMejac*05/(9/94 04/ W 94* O'5/94 04/18/94 C VIB:DRIL:NRR

D/DRIL:NRR

EELB:DE:NRR

CIEELB:DE:NRR

Lgrrholm CERossi SMitra Caerlinger

05/ /94 05/ /94 05/ /94 05/ /94 OGCB:DORS:NRR

AC/OGCB:DORS:NRR

D/:DORS:NRR

PWen AJKugler BKGrimes 05/ /94 05/ /94 05/ /94 OFFICIAL RECORD COPY DOCUMENT NAME: MAGNE3AT.GE

<&c rfmtC'al Cak"vyc.t

IN 94-XX April XX, 1994 Prop wipe can be etermined

in most installations

by visual inspection

without having to get too lose to hazardous

mechanism

parts if the switchgear

cabinet door can be opened fely. Pending issuance of a SAL by the manufacturer

on this problem (and/or Service Information

Letter by GE NE), Attachment

2 illustrates

one locatlo where the prop position may be seen. While fully forward prop position (t the stop) is the desired condition (maximum wipe), the absence of failures to latch along with consistent

and greater than minimum allowed prop wipe is according

to GE, indicative

of continued reliable latching.

However, cause minimum prop wipe is not a published design specification, and becau certain other factors (e.g. opening spring adjustment)

may influence

latchin reliability, GE has requested

that any licensee experiencing

Magne-Blast

eaker latching problems or noticing changed, inconsistent

or what appear to be abnormally

low prop wipe, parti-cularly following

prop bushing replacemnt, contact GE NE PDS at 215-992-6049.

In the meantime, pending installat

n of a second prop spring in its affected breakers, Maine Yankee has shift to the extent possible, its available

dual prop spring breakers to loca Ions where operability

requires assured latching reliability

for closure or closure during a design basis event. For the remaining

suspect breakers, Mane Yankee has undertaken

expedited

inspections

with the assistance

of G E PDS to aid in its operabil-ity determinations.

NRC Information

Notice 94-X issued April XX, 1994, dis-cusses other recently identified

problems impactin Magne-Blast

operability, related to defective

and improperly

installed

GE CR 940 limit switches.This information

notice requires no specific ac on or written response.If you have any questions

about the information

in thi notice, please contact the technical

contacts listed below or the appropriate

ffice of Nuclear Reactor Regulation (NRR) project manager.ORIG /S/'D BY BKGRIMES Brian K. Grimes, Directo Division of Operating

Reac or Support Office of Nuclear Reactor R ulation Technical

contacts:

Stephen Alexander, NRR (301) 504-2995 Kamalakar

Naidu, NRR (301) 504-2980 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued NRC Information

Notices VIB:DRIL VIB:DRIL SC/VIB:DRIL

TECHED Salexander

Knaidu Gcwalina 41./V (,AA-04/ /94 04/ /94 04/ /94 04/AR/94 C/VIB:DRIL:NRR

D/DRIL:NRR

EELB:DE:NRR

C/EELB:DE:NRR

Lnorrholm

CERossi SMitra Cberlinger

04/ /94 04/ /94 04/ /94 04/ /94 OGCB:DORS:NRR

AC/OGCB:DORS:NRR

D/:DORS:NRR

PWen AJKugler BKGrimes 04/ /94 04/ /94 04/ /94 OFFICIAL RECORD COPY DOCUMENT NAME: MAGNBLST.IN

IN 94-XX April XX, 1994 Prop wipe can be termined in most installations

by visual inspection

without having to get too c eto hazardous

mechanism

parts if the switchgear

cabinet door can be opened sa ly. Pending issuance of a SAL by the manufacturer

on this problem (and/or a rvice Information

Letter by GE NE), Attachment

2 illustrates

one location ere the prop position may be seen. While fully forward prop position (to t stop) is the desired condition (maximum wipe), the absence of failures to lat h along with consistent

and greater than minimum allowed prop wipe is, a cording to GE, indicative

of continued reliable latching.

However, bec se minimum prop wipe is not a published design specification, and because ertain other factors (e.g. opening spring adjustment)

may influence

latching eliability, GE has requested

that any licensee experiencing

Magne-Blast

breker latching problems or noticing changed, inconsistent

or what appears o be abnormally

low prop wipe, parti-cularly following

prop bushing replacem t, contact GE NE PDS at 215-992-6049.

In the meantime, pending installatlo

of a second prop spring in its affected breakers, Maine Yankee has shifte to the extent possible, its available

dual prop spring breakers to loca ions where operability

requires assured latching reliability

for closure or eclosure during a design basis event. For the remaining

suspect breakers, M ne Yankee has undertaken

expedited

inspections

with the assistance

of G NE PDS to aid in its operabil-ity determinations.

NRC Information

Notice 94- , issued April XX, 1994, dis-cusses other recently identified

problems impact g Magne-Blast

operability, related to defective

and improperly

installed

GE R2940 limit switches.This information

notice requires no specific ction or written response.If you have any questions

about the information

in \this notice, please contact the technical

contacts listed below or the appropri te Office of Nuclear Reactor Regulation (NRR) project manager.ORIG /S/'D BY BKG IMES Brian K. Grimes, irector Division of Operat ng Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts: Stephen Alexander, NRR (301) 504-2995 Kamalakar

Naidu, NRR (301) 504-2980 Attachments:

1. Details of Failure Mode and Contributing

Factors 2. Magne-Blast

Prop Mechanism

Diagram 3. List of Recently Issued_ RC Information

Notices VIB:DRIL VIB:DRI SC/VIB:DRIL

Salexand 9k Knaidu Gcwalina 04//5'/94

04/14/94 s '4, 04/ /94 C/VIB:DRIL:NRR

D/DRIL:NRR

EELB:DE:NRR

Lnorrholm

CERossi SMitra 04/ /94 04/ /94 04/ /94 OGCB:DORS:NRR

AC/OGCB:DORS:NRR

D/:DORS:NRR

PWen AJKugler BKGrimes 04/ /94 04/ /94 04/ /94 TECHED 04/ /94 C/EELB:DE:NRR

Cberlinger

04/ /94 OFFICIAL RECORD COPY DOCUMENT NAME: MAGNBLST.IN