Information Notice 1993-99, Undervoltage Relay & Thermal Overload Setpoint Problems

Undervoltage Relay & Thermal Overload Setpoint Problems

ML031060586
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:	12/21/1993
Revision:	0
From:	Grimes B K Office of Nuclear Reactor Regulation
To:
References
IN-93-099, NUDOCS 9312150073
Download: ML031060586 (12)

UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555December 21, 1993NRC INFORMATION NOTICE 93-99: UNDERVOLTAGE RELAY AND THERMAL OVERLOADSETPOINT PROBLEMS

Addressees

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

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this informationnotice to alert addressees to continuing discoveries of undervoltage relay andthermal overload setpoints that are set too low. It is expected thatrecipients will review the information for applicability to their facilitiesand 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.BackgroundIn August 1976, the NRC wrote generic letters to all LWR licensees regardingthe need for licensees to evaluate any generic implications of several eventsat the Millstone site involving episodes of sustained degraded grid voltage.On June 2, 1977, as part of multiplant action MPA-23, the staff stated itsposition that all licensees must have a second level of undervoltageprotection with a time delay. (During degraded grid voltage episodes,undervoltage relays and thermal overload protective relays protect the safetyequipment.) In a generic letter dated August 8, 1979, the NRC requested alllicensees to determine the capability of the offsite power system to operateall required loads within their voltage ratings under all conditions withintheir design basis. The licensees reviewed their undervoltage relay setpointson each of these occasions. In 1981, the NRC issued Branch TechnicalPosition, Power System Branch-1, "Adequacy of Station Electric DistributionSystem Voltages," which discussed, among other things, the addition of asecond undervoltage relay with an associated time delay. Between 1981 and1992, the NRC issued two information notices, in which it discussedundervoltage relay setpoints and other concerns:1. IN 84-02, "Operating a Nuclear Power Plant at VoltageLevels Lower than Analyzed," issued January 10, 1984.2. IN 91-29, "Deficiencies Identified During Electrical DistributionSystem Functional Inspections," issued April 15, 1991.9312150073 PDR E No4tEC 93-0 1e ' , t IN 93-99December 21, 1993 . IN 91-29, Supplement 1, TDeficiencies Identified During

--"VIN 93-99December 21, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Bran K. rimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of UndervoltageRelay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information Notices Attachment 1IN 93-99December 21, 993Representative List of Undervoltaqe Relay Set Point Revision Notifications andTechnical Specification Change Proposals for 1988-1993Event NotificationNumberLicenseeEvent Notification Date113741404300000147801654017121PilgrimPilgrimPilgrim111January 30, 1988November 18, 1988June 30, 1988151Cooper 1Crystal River 3Robinson 2February 17,September 8,November 16,1989198919895111832218466188921902320021Oconee 1, 2 and 3McGuire 1 and 2St. Lucie 2Haddam Neck 1Calvert Cliff 1 and 2Ft. CalhounKewaunee 1Salem 2Dresden 2 and 3Dresden 2Zion 1 and 2April 24, 1990May 14, 1990July 14, 1990August 2, 1990December 6, 1990February 12, 1991February 20, 1991February 27, 1991August 23, 1991November 20, 1991December 19, 199151251204352050320542216912228122498152515225802265822847 (TOL)22918231482319123338233652338523439 (TOL)23452235762378423932000002422924384Indian Point 3Dresden 3Washington Nuclear 2Washington Nuclear 2Vermont YankeeQuad Cities 1 and 2LaSalle 1 and 2LaSalle 2Crystal River 3Grand GulfComanche Peak 2Crystal River 3Zion 1 and 2Byron 1 and 2CallawayCrystal River 3Dresden 2 and 3January 9, 1992January 22, 1992February 19, 1992March 1, 1992April 1, 1992April 7, 1992April 27, 1992April 29, 1992May 1, 1992May 11, 1992May 13, 1992June 4, 1992July 2, 1992July 24, 1992July 23, 1992September 14, 1992October 6, 1992*TOL -Thermal Overload Attachment 1IN 93-99December 21, 1993 Event Notification Licensee Event Notification Date ClassNumber00000 Prairie Island 1 & 2 November 6, 1992 100000 St. Lucie 1 November 30, 1992 124757 Maine Yankee December 15, 1992 500000 Diablo Canyon 1 and 2 December 22, 1992 124845 Point Beach 1 and 2 January 7, 1993 125248 (TOL) Pilgrim March 29, 1993 525362 South Texas April 6, 1993 5Events Notification Number-00000 Licensees whose undervoltage relay setpointnotifications to the NRC were reported by LERs, licensee letter, etc., andevent notification numbers if any, were not known.Class Definitions:1. Undervoltage Relay setpoints were found to be incorrect because ofdesign errors.2. Undervoltage Relay setpoints, as found, were not the same as required bythe technical specification.3. Safety load circuit breaker thermal overloads or other trip setpointswere too low because of design errors.4. Safety load circuit breaker thermal overload, or other trip setpoints,as found, were not the same as required by the technical specification.5. Membership in one of the preceding four classes could not be definitelyestablished because of incomplete information in the event notificatio Att~ehment 2IN 93-99December 21, 993LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to93-9893-9793-9693-9593-9493-93Motor Brakes on ValveActuator MotorsFailures of YokesInstalled on WalworthGate and Globe ValvesImproper Reset CausesEmergency DieselGenerator FailuresStorm-Related Loss ofOffsite Power Eventsdue to Salt Buildupon Switchyard InsulatorsUnauthorized ForcedEntry into the Pro-tected Area at ThreeMile Island Unit 1 onFebruary 7, 1993Inadequate Control ofReactor Coolant SystemConditions During ShutdownPlant Improvements toMitigate Common Depend-encies in ComponentCooling Water SystemsInadequate QualityAssurance Program ofVendor SupplyingSafety-Related Equipment12/20/9312/17/9312/14/9312/13/9312/09/9312/08/9312/07/9312/07/93All holders of OLs and CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactorslocated close to a largebody of salt water.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactorsand all recipients ofNUREG-0040, 'License Con-tractor and Vendor Inspec-tion Status ReportR (WhiteBook)..93-9291-21,Supp. 1OL -Operating LicenseCP = Construction Permit IN 93-99December 21, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Odginal signed byBrian K. GrimesBrian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of UndervoltageRelay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information NoticesE plion:The stress laid by the initial reviewer on thelicensees and the staff should feel for such apreblem, viz. low UVR set points, has been allpresent IN.degree of concern thatwidespread and persistentbut eliminated from the(SEE PREVIOUS CONC.)*C.MORRIS15 NOV. 93(S/D)*SEE PREVIOUS CONCURRENCES*DO RS/OGCB

• C/OGCB:DORS:NRR D/DORS:NRRNCampbell GHMarcus07/30/93 08/10/9312//$193*EELB:DE:NRRCMorris04/28/93*SC/EELB:DE:NRREWWeiss95/19/93*C/EELB:DE:NRRCHBerlinger05/19/93*D/DE: NRRJTWiggins07/23/93*RPB:ADMTech Ed07/13/93# Concurred in electronically by JMain.DOC NAME: 93-99.IN IN 93-XXNovember XX, 993This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of UndervoltageRelay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information NoticesException:The stress laid by the initial reviewer on the degree of concern thatlicensees and the staff should feel for such a widespread and persistentproblem, viz. low UVR set points, has been all but eliminated from thepresent IN. G4'C.MORRIS15 NOV. 93Document Name: G:\SHARED\R3UNRELS.IN*SEE PREVIOUS CONCURRENCES# Concurred in electronically byD/DORS:NRR *C/OGCB: DORS:NRRBKGrimes GHMarcus11/ /93 A 08/10/93*C/EELB:DE:NRR *D/DE:NRRCHBerlinger JTWiggins05/19/93 07/23/93JMain.*OGCB:DORS:NRRNCampbell07/30/93*RPB:ADMTech Ed07/13/93*EELB:DE:NRRCMorris04/28/93*SC/EELB:DE:NRREWWeiss05/19/93&Wp: & 4 Lso1 IN 93-XXNovember XX, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of UndervoltageRelay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information NoticesDocument Name:G:\SHARED\R3UNRELS.IN*SEE PREVIOUS CONCURRENCES# Concurred inD/DORS:NRRBKGrimesll/ /93*C/EELB:DE:NRRCHBerlinger05/19/93electronically by*C/OGCB:DWRS:NRRGHMarcus08/10/93*D/DE:NRRJTWiggins07/23/93JMain.*OGCB: DORS:NRRNCampbell07/30/93*RPB:ADMTech Ed07/13/93*EELB:DE:NRRCMorris04/28/93*SC/EELB:DE:NRREWWeiss05/19/93 IN 93-XXAugust XX, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operating Reactor SupportOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of UndervoltageRelay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCESDocument Name: UNRELSET.INDORS/OGCBNCampbell07/30/93D/DORS:BKGrime08/ /93C/OGCB: DORS:NRRGHMarcus6#/W08/to /93*EELB:DE:NRRCMorris04/28/93*SC/EELB:DE:NRREWWeiss05/19/93*C/EELB:DE:NRRCHBerlinger05/19/93*D/DE : NRRJTWiggins07/23/93*RPB:ADMTech Ed07/13/93# Concurred in electronically by JMai IN 93-XXAugust XX, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operational EventsAssessmentOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of Undervoltage Relay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCESDocument Name: UNRELSET.INDRS/OGCBNCampbell07/8* /93D/DORS:NRRBKGrimes07/ /93C/OGCB:DORS:NRRGHMarcus07/ /93*EELB:DE:NRRCMorris04/28/93*SC/EELB:DE:NRREWWeiss05/19/93*C/EELB:DE:NRRCHBerlinger05/19/93*D/DE:NRRJTWiggins07/23/93*RPB:ADMTech Ed07/13/93# Concurred in electronically by JMai _> K_> IN 93-XXJuly XX, 1993 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Brian K. Grimes, DirectorDivision of Operational EventsAssessmentOffice of Nuclear Reactor RegulationTechnical contact:C. Morris, NRR(301) 504-2778

Attachments:

1. Representative List of Undervoltage Relay Setpoint Revisions 1988-19932. List of Recently Issued NRC Information Notices*SEE PREVIOUS CONCURRENCESDocument Name: UNRELSET.INDORS/OGCB DNCampbell BI07/ /93 0,*C/EELB:DE:NRRCHBerlinger05/19/93/DORS:NRRKGrimes7/ /24*EELB:DE:NRRCMorris04/28/93*SC/EELB:DE:NRREWWeiss05/19/93MarcusT/ /93*RPB:ADMTech Ed07/13/93# Concurred in electronically by JMain.