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 E Office of Nuclear Reactor Regulation
To:
References
IN-90-043, NUDOCS 9006250069
Download: ML031130291 (7)

UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555June 29, 1990NRC INFORMATION NOTICE NO. 90-43: MECHANICAL INTERFERENCE WITH THERMAL TRIPFUNCTION IN GE MOLDED-CASE CIRCUIT BREAKERS

Addressees

All holders of operating licenses or construction permits for nuclear powerreactors.

Purpose

This information notice is Intended to-alert addressees of a manufacturingdeviation in certain General Electric (GE) molded-case circuit breakers (MCCBs)which may result in mechanical interference with the thermal overcurrent tripfunction 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 verifythat plant components meet the functional performance requirements of theirsafety-related applications. It is expected that recipients will review theinformation for applicability to their facilities and consider actions, asappropriate, to avoid similar problems. However, suggestions contained in thisinformation notice do not constitute NRC requirements; therefore, no specificaction or written response is required.

Description of Circumstances

In 1989, General Public Utilities-Nuclear (GPUN), the licensee for the OysterCreek Nuclear Power Plant (Oyster Creek), purchased 170 TED-type and THED-typeMCCBs from GE Nuclear Energy in San Jose, California. The MCCBs were purchasedas safety-related items and were supplied with GE Nuclear Energy productquality 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 theirHumacao, Puerto Rico, factory and installed UVRs at their accessory installa-tion facility in Mascot (Knoxville), Tennessee." The MCCBs were dedicated by GENuclear Energy for use in safety-related applications at Oyster Creek, inpart, 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-testedat Oyster Creek prior to installation. This MCCB had a UVR installed in thestandard location by phase IC" (right-hand side). The MCCB failed to trip when300-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 90-43June 29, 1990 the thermal trips operated'satisfactorily. The licensee returned the MCCB toGE 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-testedseven more UYR-equipped MCCBs from the same'order. Five of the seven, failed topass the overcurrent trip test (also at 300 percent of rated current) onphase C only. In addition, GPUN reported opening one of the failed MCCBs,.removing'the UYR, and retesting the MCCB with satisfactory results for thethermal overcurrent trip test on phase C. These experimental results suggestedthat the UVR had been interfering with the operation of the phase-C thermalovercurrent 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 thermalelement, but rather on the common tripper bar that trips all three phases orpoles.Discussion:On May 24, 1990, an NRC representative observed the GE ED&C testing of the fiveGE TED-type MCCBs with UYRs installed (GE catalog number TED136100UY4RS) whichhad failed pre-installation testing at Oyster Creek.- Inspection and testingrevealed that the cause of the failure of the overcurrent trip function wasimproper 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 ofthe MCCBs unless internal UYRs are installed. The Oyster Creek-MCCBs passedthe thermal overcurrent trip tests at the GE Puerto Rico factory because theUYRs had not yet been installed. After the UYRs were installed at the GE ED&CKnoxville facility, the presence of the misoriented calibration screw springclips 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 dedicationof CGIs for safety-related applications were exhibited by the undetectedmisorientation of the calibration screw spring clips and the lack of adequateretesting following installation of the UVRs. GE ED&C has indicated thataction 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 theinstallation of UYRs at their Knoxville facility.Although GE ED&C's failure analysis was demonstrated by testing, it has notbeen firmly established that this condition is isolated to the MCCB shipment inquestion. However, GE ED&C has stated that the problem is limited only to thethermal 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 aresult of this model's unique, integral overcurrent trip mechanisms and theproximity of the phase C thermal trip mechanism to the tripping arm of aninstalled UVR..9 IIN 90-43June 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 assafety-related components through GE Nuclear Energy and were supplied with thevendor'-s 10 CFR Part 50 Appendix B quality assurance certifications, thistesting was performed by the licensee in addition to the normal quality assur.-ance receipt inspection.This information notice requiresyou have any questions about 'theof the technical contacts listedno specific action or written response. Ifinformation in this notice, please contact onebelow or the appropriate NRR project manager.Char Rossi DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:K. R.(301)Naidu, NRR492-0980S. D. Alexander, NRR(301) 492-0995%ase-Cut " t.. .,. Em : lsr; -r. M

Attachment:

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• ConItDt10n PermitUNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D.C. 206OFFICIAL BUSINESSPENALTY FOR PRIVATE USE. $300PIPT LAS AIL1IPOSTAGE & FEES PAIDI1USNRC1 IN 90-43June 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 assafety-related components through GE Nuclear Energy and were supplied with thevendor's 10 CFR Part 50 Appendix B quality assurance certifications, thistesting was performed by the licensee in addition to the normal quality assur-ance receipt inspection.This information notice requiresyou have any questions about theof the technical contacts listedno specific action or written response. Ifinformation in this notice, please contact onebelow or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:K. R.(301)Naidu, NRR492-0980S. D. Alexander, NRR(301) 492-0995

Attachment:

List of Recently Issued NRC Information NoticesDocument Name:INFO NOTICE ALEXANDER/2*SEE PREVIOUS CONCUO6/>'90*OGCB:DOEA:NRR*VIB:DRIS:NRRNCampbell SAlexander:sda06/22/90 6/06/90*C/OGCB:DOEA:NRR*RPB:ADMCHBerlinger TechEd06/19/90 06/05/90*VIB:DRIS:NRR *VIB:DRIS:NRRl KNaidu UPotapovs6/06/90 6/06/90*D/DRIS:NRRBKGrimes06/07/90*C/VIB:DRIS:NRREWBrach6/06/90 IN 90-XXJune X, 1990 The failure of the Oyster Creek MCCBs in safety-related applications could havejeopardized the safety of the plant. Oyster Creek's routine pre-installationtesting procedures detected and prevented the use of the faulty MCCBs. Al-though the MCCBs were procured as safety-related components through GENE andwere supplied with the vendor's 10 CFR Part 50 Appendix B quality assurancecertifications, this testing was performed by the licensee in addition to thenormal quality assurance receipt inspection.This information notice requiresyou have any questions about theof the technical contacts listedno specific action or written response. Ifinformation in this notice, please contact onebelow or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical Contacts:K. R.(301)Naidu, NRR492-0980S. D. Alexander, NRR(301) 492-0995

Attachment:

List of Recently Issued NRC Information NoticesDocument N*SEE PREVIOUS:NRRNCampbell06 /JVJ/90Clame: INFO NOTICE ALEXANDER/@FONCURRENCES ID/DOEA:NRR B RR B:ADMCERossi CHB~~ ih TechEd06/ /90 06/1j/90 06/05/90rVIB:DRIS:NRR *VIB:IDRIS:NRR *VIB:DRIS:NRRSAlexander:sda KNaidu UPotapovs6/06/90 6/06/90 6/06/90*D/DRIS:NRRBKGrimes06/07/90*C/VIB:DRIS:NRREWBrach6/06/90 IN 90-XXJune X, 1990 Oyster Creek's routine preinstallation testing procedures detected andprevented the use of faulty MCCBs in safety-related applications which couldhave jeopardized s t the plant. It should be noted that this testingwas conducted tow w c that these components were procured as safety-related and came with vendor 10 CFR Part 50 Appendix B quality assurancecertifications.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact oneof the technical contacts listed below or the appropriate NRC regional office.Charles E. Rossi, DirectorDivision of Operational Events AssesmentOffice of Nuclear Reactor RegulationTechnical Contacts: K. R. Naidu, NRR (301) 492-0980S. D. Alexander, NRR (301) 492-0995

Attachment:

List of Recently Issued NRC Information NoticesOFC :VIB:DRIS:NRR :VIB:DRIS:NRR :VIB:DXIS:NRR :C:VIB-DRIS:NRR:TECH ED :D:DR S:NRR______------ ___________----_____ :--q___ ------- A- -- --------------:dn --NAME :SAlexander:sda :N+df :UPo povs fE) C Fc -- :7tl :B^ yrimes__ __ _ _ _._..:V:- -----. -- __- _ ------:6/, /90:6DATE :6/6 /90 :6/ 9 :6/ /90 :6/ 6/90 :6/ F/90 .6 9 0 avO_..OFC G B:DOEA:NRR :GCB:DOEA:NRR :C:GCB:DOEA:NRR:D:DOEA NRR :NAME :JJRam :CBerlinger :ERossi :DATE :6 /90 :6/ /90 6/ /90 :6/ /90OFFICIAL RECORD COPYDocument Name: GE MCCB UVR INFO NOTICE0004.0.0