Information Notice 1992-27, Thermally Induced Accelerated Aging and Failure of ITE/Gould A.C. Relays used in Safety-Related Applications

Thermally Induced Accelerated Aging and Failure of ITE/Gould A.C. Relays used in Safety-Related Applications

ML031200594
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:	04/03/1992
Revision:	0
From:	Rossi C E Office of Nuclear Reactor Regulation
To:
References
IN-92-027, NUDOCS 9203270157
Download: ML031200594 (10)

P. .I3UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555April 3, 1992NRC INFORMATION NOTICE 92-27: THERMALLY INDUCED ACCELERATED AGING ANDFAILURE OF ITE/GOULD A.C. RELAYS USEDIN SAFETY-RELATED APPLICATIONS

Addressees

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

Purpose

The U.S.. Nuclear Regulatory Commission (NRC) is issuing this information noticeto alert addressees to problems resulting from the accelerated aging andfailure of 120Y ac relays manufactured by the ITE/Gould Manufacturing Company(currently Telemecanique). The relay failures rendered portions of the associ-ated safety-related systems inoperable. It is expected that recipients willreview the information for applicability to their facilities and consideractions, as appropriate, to avoid similar problems. However, suggestionscontained in this information notice are not NRC requirements; therefore, nospecific action or written response is required.

Description of Circumstances

On November 23, 1991, while performing an eighteen month engineered safetyfeatures operability test, the licensee for the Millstone Nuclear PowerStation, Unit 3, noted that control power was interrupted to three safety-related motor operated valves (MOYs). The valves were located in the charging,component cooling water, and steam generator atmospheric dump systems. Thelicensee inspected the valves' control power circuitry and determined thatthree normally energized auxiliary relays had failed. These relays providedcontrol power alarms and thermal overload protection for the MOYs. The relayfailures rendered each valve inoperable.The relays, which had been in service for about seven years, were class J10relays with J20M magnet block assemblies and standard G1OJA126, 120V, 60 cyclecoil assemblies manufactured by the ITE/Gould Manufacturing Company. Inspectionof the relays revealed that the movable plastic armature carrier, which surroundsthe core and coil, and the retainer for the magnet yoke assembly were discolored,brittle and severely cracked. Insulation degradation was severe, allowingelectrical shorts to develop within the coils. The licensee concluded that thefailures resulted from the thermal aging of the coil assemblies and plasticparts near the coil assemblies.9203270157 ;Z4- IN 92-27April 3, 1992 The failed relays were mounted shoulder to shoulder in a horizontal "ganged"arrangement on a universal mounting strip supplied by the manufacturer. Thethree relays that failed were each mounted in the middle of a ganged relaycluster. The relays were originally qualified, individually, for the life ofthe plant. However, the qualification process did not account for the use ofthe relays in the ganged arrangement. The licensee stated that the potentialheat induced degradation of "weak-link" materials such as the plastic armaturecarrier was not considered in the qualification test report.The licensee inspected relays in other safety and nonsafety systems and foundsimilar discoloration and embrittlement caused by overheating, but found noadditional failures. The Millstone licensee has replaced approximately 260relays with identical components from spare motor control centers. Long termcorrective actions include periodic monitoring and replacement and/or physicalseparation of ganged relays.During the period April 1987 through August 1987, the licensee for the SeabrookGenerating Station experienced similar failures of ITE/Gould J-10 relays.Following those failures, Telemecanique submitted a report to the NRC underTitle 10 of the Code of Federal Regulations (10 CFR), Part 21 (Part 21 report)describing the Uailures at Seabrook. The report attributed the overheatingfailures to the special low voltage coils in the J10 relays that were suppliedto the Seabrook Nuclear Station. Telemecanique stated that the relays suppliedto Seabrook were equipped with a non-standard magnet coil (identified as 816with 50 ohms resistance) and, therefore, the failure mode would not be experi-enced at any other facility. The licensee for the Seabrook Station submitted aLicensee Event Report (LER) to the NRC under 10 CFR Part 50.73 describing therelay failures and their root cause analysis. The licensee stated in the LERthat, "...It was originally believed that excessive temperature resulted fromthe close proximity of six normally energized relays...Subsequent investigationled to the identification of relays not in close proximity with other energizedcomponents that showed slight discoloration." However, the Seabrook licenseeaccepted the Telemecanique Part 21 report conclusions that the failures weredue to the heat generated by the energized, non-standard coil.The recent failures at Millstone suggest that the Seabrook licensee's originalconclusion may have been accurate. The gang mounting ("close proximity") ofthese relays was likely a major contributor to the accelerated aging withthe condition being exacerbated by the additional heat generated by the contin-uously energized coil.The J10 relay is one of a family of J-class relays currently manufactured byTelemecanique as commercial grade items. Although the NRC staff is not awareof the failure of any of the other J-class relays, these relays could be suscep-tible to similar heat induced degradation when gang mounte IN 92-27April 3, 1992 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: N. Fields, NRR(301) 504-1173K. Naidu, NRR(301) 504-2980R. Spence, AEOD(301) 492-8609

Attachment:

List of Recently Issued NRC Information Notices mCIin W11I2I C0U-%MM*0 aCl52AttachmentIN 92-27April 3, 1992 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to92-26 Pressure Locking of Motor- 04/02/92 All holders of OLs or CPsOperated Flexible Wedge for nuclear power reactors.Gate Valves92-25 Potential Weakness in 03/31/92 All holders of OLs or CPsLicensee Procedures for A for nuclear power reactors.Loss of the RefuelingCavity Water92-24 Distributor Modification to 03/30/92 All holders of OLs or CPsCertain Coemercial-Grade for nuclear power reactors.Agastat Electrical Relays92-23 Results of Validation Test- 03/27/92 All holders of OLs or CPsing of Motor-Operated Valve for nuclear power reactorsDiagnostic Equipment and all vendors of motor-operated valve (MOV) diag-nostic equipment.92-22 Criminal Prosecution and 03/24/92 All holders of OLs or CPsConviction of Wrongdoing for nuclear power reactors.Committed by A Coeuercial-Grade Valve Supplier92-21 Spent Fuel Pool Reactivity 03/24/92 All holders of OLs or CPsCalculations for nuclear power reactors.92-20 Inadequate Local Leak Rate 03/03/92 All holders of OLs or CPsTesting for nuclear power reactors.92-19 Misapplication of Potter 5 03/02/92 All holders of OLs or CPsBrumfield MDR Rotary Relays for nuclear power reactors.92-18 Potential for Loss of Re- 02/28/92 All holders of OLs or CPsmote Shutdown Capability for nuclear power reactors.during A Control Room FireOL -Operating LicenseCP -Construction Permit(.XX I>a a0 I5 ;

IN 92-27April 3, 1992 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts:N. Fields, NRR(301) 504-1173K. Naidu, NRR(301) 504-2980R. Spence, AEOD(301) 492-8609

Attachment:

List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCEOFC :DOEA:OEAB :AEOD:ROAB :DRIS:RVIB :ADM:RPB :RI :SC:DOEA:OEAB:NAME :NFields* :RSpence* :KNaidu* :JMain* :RBarkley* :DFischer* :DATE :03/04/92 :03/04/92 :03/09/92 :01/23/92 :03/05/92 :03/11/92OFC :C:DOEA:OEAB :C:DOEA:OGCB :D:DOEA : : :_____ _______ ___----------:- A -------:------------ :------------:------------ :---------NAME :AChaffee* :CBerlinger* : :DATE :03/11/92 :03/18/92 :03/2;792 : : :OFFICIAL RECORD COPYDocument Name: IN DRAFT MILLSTONE IN 92-XXMarch xx, 1992 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactone of the technical contacts listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contacts: N. Fields, NRR(301) 504-1173K. Naidu, NRR(301) 504-2980R. Spence, AEOD(301) 492-8609

Attachment:

List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCEOFC :DOEA:OEAB :AEOD:ROAB :DRIS:RVIB :ADM:RPB :RI :SC:DOEA:OEAB:NAME :NFields* :RSpence* :KNaidu* :JMain* :RBarkley* :DFischer* :DATE :03/04/92 :03/04/92 :03/09/92 :01/23/92 :03/05/92 :03/11/92OFC :C:DOEA:OEAB :C:D0E 9yt D:DOEA : :________---------:----1--- ---------------------------- ------------ ---------NAME :AChaffee* :CBer :CRossiDATE :03/11/92 ./ 9 : / /92 :OFFICIAL RECORD COPYDocument Name: IN DRAFT MILLSTONE

• SEE PREVIOUS CONCURRENCEOFC :DOEA:OEAB :AEOD:ROAB :DRIS:RVIB :ADM:RPB :RI :S OEA:OEAB:NAME :NFields* :RSpence* :KNaidu* :JMain* :RBarkley* :DF scner :DATE :03/04/92 :03/04/92 :03/09/92 :01/23/92 :03/05/92 : 3/gi/92OFC :C:DOEA:OEAB :C:DOEA:OGCB :D:DOEA----- : <F; ------------ :------------:------------:-- ---------:--- ------------ ___NAME :AC~affee :CBerlinger :CRossi : : :DATE :3 /11/92 : / /92 : / /92 : : :OFFICIAL RECORD COPYDocument Name: IN DRAFT MILLSTONE

• SEE PREVIOUS CONCURRENCEOFC :DOEA:OEAB :AEOD:ROAB :DRIS:RVIB :ADM:RPB :RI :SC:DOEA:OEAB:NAME :NFields* :RSpence* : :JMain* :RBarkley* :DFischerDATE :03/04/92 :03/04/92 :5 /92 :01/23/92 :03/05/92 : / /92OFC :C:DOEA:OEAB :C:DOEA:OGCB :D:DOEANAME :AChaffee :CBerlinger :CRoss: : :DATE: / /92 : / /92 : / /92 : : :OFFICIAL RECORD COPYDocument Name: IN DRAFT MILLSTONE

• SEE PREVIOUS CONCURRENCEOFC :DOEA:OEAB :AEOD:ROAB :DRIS:RYIB :ADM:RPB :RI :SC:DOEA:OEAB:NAME :NFields* :RSpence* :KNaidu :JMain* :RBark1e! :DFischer :--------- -4---- -------DATE :03/04/92 :03/04/92 : / /92 :01/23/92 :3/v/92 : / /92OFC :C:DOEA:OEAB :C:DOEA:OGCB :D:DOEA___- __ _________ __ ------------NAME :AChaffee :CBerlinger :CRossi :DATE ://92 :/ /92 :/ /92 : :OFFICIAL RECORD COPYDocument Name: IN DRAFT MILLSTONE tgm;7it iy2LIuOFC :DOEA:OEAB :AEOD:ROAB :DRIS:RVIB :AMM:RPB" :RI :SC:DOEA:OEAB:NAME :NFields or :RSpence :KNaidu :JMain :RBarkley :DFischer :DATE : 3 /T[/92 :3 / /92 : / /92 : /2-4/92 : / /92 : / /92 :OFC :C:DOEA:OEAB :C:DOEA:OGCB :D:DOEA___- : --- --- --- _ _______ _ _ ------------NAME :AChaffee :CBerllnger :CRossiDATE ://92 :/ /92 :/ /92 :OFFICIAL RECORD COPYDocument Name: IN DRAFT MILLSTONE