Information Notice 1990-43, Mechanical Interference with Thermal Trip Function in GE Molded-Case Circuit Breakers

Mechanical Interference with Thermal Trip Function in GE Molded-Case Circuit Breakers

ML031130291
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:	06/29/1990
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-90-043, NUDOCS 9006250069
Download: ML031130291 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 June 29, 1990

NRC INFORMATION NOTICE NO. 90-43: MECHANICAL INTERFERENCE WITH THERMAL TRIP

FUNCTION IN GE MOLDED-CASE CIRCUIT BREAKERS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is Intended to-alert addressees of a manufacturing

deviation in certain General Electric (GE) molded-case circuit breakers (MCCBs)

which may result in mechanical interference with the thermal overcurrent trip

function when internal accessory undervoltage release (UVR) devices are in- stalled. In addition, the information contained herein is intended to empha- size the importance of conducting thorough pre-installation testing to verify

that plant components meet the functional performance requirements of their

safety-related applications. 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

In 1989, General Public Utilities-Nuclear (GPUN), the licensee for the Oyster

Creek Nuclear Power Plant (Oyster Creek), purchased 170 TED-type and THED-type

MCCBs from GE Nuclear Energy in San Jose, California. The MCCBs were purchased

as safety-related items and were supplied with GE Nuclear Energy product

quality certificates (PQCs). GE Nuclear Energy purchased the MCCBs as commer- cial grade items (CGIs) from the GE Electrical Distribution and Control Depart- ment in Plainville, Connecticut (GE-ED&C), who manufactured the MCCBs at their

Humacao, Puerto Rico, factory and installed UVRs at their accessory installa- tion facility in Mascot (Knoxville), Tennessee." The MCCBs were dedicated by GE

Nuclear Energy for use in safety-related applications at Oyster Creek, in

part, on the basis of testing performed at the Puerto Rico factory.

In November 1989, one 15-ampere TED-type MCCB from this order was bench-tested

at Oyster Creek prior to installation. This MCCB had a UVR installed in the

standard location by phase IC" (right-hand side). The MCCB failed to trip when

300-percent of rated current was applied to phase C of the MCCB (a time- overcurrent test of the thermal trip function), whereas on phases A and B,

9006250069 Z

IN 90-43 June 29, 1990 the thermal trips operated'satisfactorily. The licensee returned the MCCB to

GE Nuclear Energy for failure and root cause analysis. The results of the.

analysis have not yet been reported. . ;

In May 1990, according to GPUN reports, Oyster Creek technicians bench-tested

seven more UYR-equipped MCCBs from the same'order. Five of the seven, failed to

pass the overcurrent trip test (also at 300 percent of rated current) on

phase C only. In addition, GPUN reported opening one of the failed MCCBs,.

removing'the UYR, and retesting the MCCB with satisfactory results for the

thermal overcurrent trip test on phase C. These experimental results suggested

that the UVR had been interfering with the operation of the phase-C thermal

overcurrent trip element because of its close proximity to the phase-C element.

However, it should be noted that the UVR is not intended to act on the thermal

element, but rather on the common tripper bar that trips all three phases or

poles.

Discussion:

On May 24, 1990, an NRC representative observed the GE ED&C testing of the five

GE TED-type MCCBs with UYRs installed (GE catalog number TED136100UY4RS) which

had failed pre-installation testing at Oyster Creek.- Inspection and testing

revealed that the cause of the failure of the overcurrent trip function was

improper installation of the calibration screw spring clips by the Puerto Rico

-factory 4nstead-of-iniproper installation of the UVRs by the Knoxville faci- lity, as previously believed by GE Nuclear- YEnGy.-GE-ED&C-stated-that--the- misoriented calibration screw spring clips have no effect on the operability of

the MCCBs unless internal UYRs are installed. The Oyster Creek-MCCBs passed

the thermal overcurrent trip tests at the GE Puerto Rico factory because the

UYRs had not yet been installed. After the UYRs were installed at the GE ED&C

Knoxville facility, the presence of the misoriented calibration screw spring

clips caused mechanical interference between the UVR and the thermal over- current trip function. This was not detected at the GE ED&C Knoxville faci- lity, because testing of all MCCBs normal functions was not performed.

Deficiencies in manufacturing quality control and in the program for dedication

of CGIs for safety-related applications were exhibited by the undetected

misorientation of the calibration screw spring clips and the lack of adequate

retesting following installation of the UVRs. GE ED&C has indicated that

action will be taken, including design changes if necessary, to prevent inter- ference between the calibration screw spring clips and the UYRs. In addition, GE ED&C has now instituted overcurrent trip testing of MCCBs following the

installation of UYRs at their Knoxville facility.

Although GE ED&C's failure analysis was demonstrated by testing, it has not

been firmly established that this condition is isolated to the MCCB shipment in

question. However, GE ED&C has stated that the problem is limited only to the

thermal overcurrent trip functions on phase C of their 3-pole, E-frame MCCBs

(types TED13XXXX and THED13XXXX), and only those equipped with UVRs. This is a

result of this model's unique, integral overcurrent trip mechanisms and the

proximity of the phase C thermal trip mechanism to the tripping arm of an

installed UVR.

.9

I

IN 90-43 June 29, 1990 Oyster Creek's routine pre-installation testing procedures detected and pre- vented the use of the faulty MCCBs. Although the MCCBs were procured as

safety-related components through GE Nuclear Energy and were supplied with the

vendor'-s 10 CFR Part 50 Appendix B quality assurance certifications, this

testing was performed by the licensee in addition to the normal quality assur.-

ance receipt inspection.

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

you have any questions about 'the information inthis notice, please contact one

of the technical contacts listed below or the appropriate NRR project manager.

Char Rossi Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: K. R. Naidu, NRR

(301) 492-0980

S. D. Alexander, NRR

(301) 492-0995

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UNITED STATES

NUCLEAR REGULATORY COMMISSION PIPT LASAIL1 WASHINGTON, D.C. 206 IPOSTAGE & FEES PAIDI

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PENALTY FOR PRIVATE USE. $300

IN 90-43 June 29, 1990 Oyster Creek's routine pre-installation testing procedures detected and pre- vented the use of the faulty MCCBs. Although the MCCBs were procured as

safety-related components through GE Nuclear Energy and were supplied with the

vendor's 10 CFR Part 50 Appendix B quality assurance certifications, this

testing was performed by the licensee in addition to the normal quality assur- ance receipt inspection.

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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: K. R. Naidu, NRR

(301) 492-0980

S. D. Alexander, NRR

(301) 492-0995 Attachment: List of Recently Issued NRC Information Notices

Document Name: INFO NOTICE ALEXANDER/2

• SEE PREVIOUS CONCU

• C/OGCB:DOEA:NRR*RPB:ADM *D/DRIS:NRR

CHBerlinger TechEd BKGrimes

O6/>'90 06/19/90 06/05/90 06/07/90

• OGCB:DOEA:NRR*VIB:DRIS:NRR *VIB:DRIS:NRR *VIB:DRIS:NRR *C/VIB:DRIS:NRR

NCampbell SAlexander:sdal KNaidu UPotapovs EWBrach

06/22/90 6/06/90 6/06/90 6/06/90 6/06/90

IN 90-XX

June X, 1990 The failure of the Oyster Creek MCCBs in safety-related applications could have

jeopardized the safety of the plant. Oyster Creek's routine pre-installation

testing procedures detected and prevented the use of the faulty MCCBs. Al- though the MCCBs were procured as safety-related components through GENE and

were supplied with the vendor's 10 CFR Part 50 Appendix B quality assurance

certifications, this testing was performed by the licensee in addition to the

normal quality assurance receipt inspection.

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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: K. R. Naidu, NRR

(301) 492-0980

S. D. Alexander, NRR

(301) 492-0995 Attachment: List of Recently Issued NRC Information Notices

Document Nlame: INFO NOTICE ALEXANDER/@F

• SEE PREVIOUS CONCURRENCES I

D/DOEA:NRR B RR B:ADM *D/DRIS:NRR

CERossi CHB~~ ih TechEd BKGrimes

06/ /90 06/1j/90 06/05/90 06/07/90

NRR rVIB:DRIS:NRR *VIB:IDRIS:NRR *VIB:DRIS:NRR *C/VIB:DRIS:NRR

NCampbell SAlexander:sda KNaidu UPotapovs EWBrach

06 /JVJ/90 6/06/90 6/06/90 6/06/90 6/06/90

IN 90-XX

June X, 1990 Oyster Creek's routine preinstallation testing procedures detected and

prevented the use of faulty MCCBs in safety-related applications which could

have jeopardized s t the plant. It should be noted that this testing

was conducted tow w c that these components were procured as safety- related and came with vendor 10 CFR Part 50 Appendix B quality assurance

certifications.

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 NRC regional office.

Charles E. Rossi, Director

Division of Operational Events Assesment

Office of Nuclear Reactor Regulation

Technical Contacts: K. R. Naidu, NRR (301) 492-0980

S. D. Alexander, NRR (301) 492-0995 Attachment: List of Recently Issued NRC Information Notices

OFC :VIB:DRIS:NRR :VIB:DRIS:NRR :VIB:DXIS:NRR :C:VIB-DRIS:NRR:TECH ED :D:DR S:NRR

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NAME :JJRam :ERossi :

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DATE :6 /90 :6/ /90 6/ /90 :6/ /90

OFFICIAL RECORD COPY

Document Name: GE MCCB UVR INFO NOTICE

0004.0.0