Information Notice 1993-99, Undervoltage Relay & Thermal Overload Setpoint Problems: Difference between revisions

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| issue date = 12/21/1993
| issue date = 12/21/1993
| title = Undervoltage Relay & Thermal Overload Setpoint Problems
| title = Undervoltage Relay & Thermal Overload Setpoint Problems
| author name = Grimes B K
| author name = Grimes B
| author affiliation = NRC/NRR
| author affiliation = NRC/NRR
| addressee name =  
| addressee name =  
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| page count = 12
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{{#Wiki_filter:UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555December 21, 1993NRC INFORMATION NOTICE 93-99: UNDERVOLTAGE RELAY AND THERMAL OVERLOADSETPOINT PROBLEMS
{{#Wiki_filter:UNITED STATES
 
NUCLEAR REGULATORY COMMISSION
 
OFFICE OF NUCLEAR REACTOR REGULATION
 
WASHINGTON, D.C. 20555 December 21, 1993 NRC INFORMATION NOTICE 93-99:   UNDERVOLTAGE RELAY AND THERMAL OVERLOAD
 
SETPOINT PROBLEMS


==Addressees==
==Addressees==
All holders of operating licenses or construction permits for nuclear powerplants.
All holders of operating licenses or construction permits for nuclear power
 
plants.


==Purpose==
==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
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
 
notice to alert addressees to continuing discoveries of undervoltage relay and
 
thermal overload setpoints that are set too low. 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.
 
Background
 
In August 1976, the NRC wrote generic letters to all LWR licensees regarding
 
the need for licensees to evaluate any generic implications of several events
 
at the Millstone site involving episodes of sustained degraded grid voltage.
 
On June 2, 1977, as part of multiplant action MPA-23, the staff stated its
 
position that all licensees must have a second level of undervoltage
 
protection with a time delay. (During degraded grid voltage episodes, undervoltage relays and thermal overload protective relays protect the safety
 
equipment.) In a generic letter dated August 8, 1979, the NRC requested all
 
licensees to determine the capability of the offsite power system to operate
 
all required loads within their voltage ratings under all conditions within
 
their design basis. The licensees reviewed their undervoltage relay setpoints
 
on each of these occasions. In 1981, the NRC issued Branch Technical
 
Position, Power System Branch-1, "Adequacy of Station Electric Distribution
 
System Voltages," which discussed, among other things, the addition of a
 
second undervoltage relay with an associated time delay. Between 1981 and
 
1992, the NRC issued two information notices, in which it discussed
 
undervoltage relay setpoints and other concerns:
      1. IN 84-02, "Operating a Nuclear Power Plant at Voltage
 
Levels Lower than Analyzed," issued January 10, 1984.
 
2. IN 91-29, "Deficiencies Identified During Electrical Distribution
 
System Functional Inspections," issued April 15, 1991.
 
9312150073       PDR           E       No4tEC         93-0                   1 e    '     ,       t
 
IN 93-99 December 21, 1993 3. IN 91-29, Supplement 1, TDeficiencies Identified During
 
--  93-99
                                                            "VIN
 
December 21, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact listed below or the appropriate Office of Nuclear
 
Reactor Regulation (NRR) project manager.
 
Bran K. rimes, Director
 
Division of Operating Reactor Support
 
Office of Nuclear Reactor Regulation
 
Technical contact:  C. Morris, NRR
 
(301) 504-2778 Attachments:
1. Representative List of Undervoltage
 
Relay Setpoint Revisions 1988-1993
2.  List of Recently Issued NRC Information Notices
 
Attachment 1 IN 93-99 December 21, 1993 Representative List of Undervoltaqe Relay Set Point Revision Notifications and
 
Technical Specification Change Proposals for 1988-1993 Event Notification  Licensee                Event Notification Date
 
Number
 
11374                Pilgrim 1                January 30, 1988            1
14043                Pilgrim 1                November 18, 1988          5
00000                Pilgrim 1                June 30, 1988              1
14780                Cooper 1                February 17, 1989          5
16540                Crystal River 3          September 8, 1989          1
17121                Robinson 2              November 16, 1989          1
18322                Oconee 1, 2 and 3        April 24, 1990              5
18466                McGuire 1 and 2          May 14, 1990                1
18892                St. Lucie 2              July 14, 1990              2
19023                Haddam Neck 1            August 2, 1990              5
20021                Calvert Cliff 1 and 2    December 6, 1990            1
20435                Ft. Calhoun              February 12, 1991          1
20503                Kewaunee 1              February 20, 1991          5
20542                Salem 2                  February 27, 1991          2
21691                Dresden 2 and 3          August 23, 1991            5
22281                Dresden 2                November 20, 1991          1
22498                Zion 1 and 2            December 19, 1991          5
22580                Indian Point 3          January 9, 1992
22658                Dresden 3                January 22, 1992
22847 (TOL)          Washington Nuclear 2    February 19, 1992
22918                Washington Nuclear 2    March 1, 1992
23148                Vermont Yankee          April 1, 1992
23191                Quad Cities 1 and 2      April 7, 1992
23338                LaSalle 1 and 2          April 27, 1992
23365                LaSalle 2                April 29, 1992
23385                Crystal River 3          May 1, 1992
23439 (TOL)          Grand Gulf              May 11, 1992
23452                Comanche Peak 2          May 13, 1992
23576                Crystal River 3          June 4, 1992
23784                Zion 1 and 2            July 2, 1992
23932                Byron 1 and 2            July 24, 1992
00000                Callaway                July 23, 1992
24229                Crystal River 3          September 14, 1992
24384                Dresden 2 and 3          October 6, 1992
*TOL - Thermal Overload
 
Attachment 1 IN 93-99 December 21, 1993 Event Notification  Licensee                Event Notification Date Class
 
Number
 
00000                Prairie Island 1 & 2    November 6, 1992            1
00000                St. Lucie 1              November 30, 1992          1
24757                Maine Yankee            December 15, 1992          5
00000                Diablo Canyon 1 and 2    December 22, 1992          1
24845                Point Beach 1 and 2      January 7, 1993            1
25248 (TOL)          Pilgrim                  March 29, 1993              5
25362                South Texas              April 6, 1993              5 Events Notification Number-00000 Licensees whose undervoltage relay setpoint
 
notifications to the NRC were reported by LERs, licensee letter, etc., and
 
event notification numbers if any, were not known.
 
Class Definitions:
1.    Undervoltage Relay setpoints were found to be incorrect because of
 
design errors.
 
2.    Undervoltage Relay setpoints, as found, were not the same as required by
 
the technical specification.
 
3.    Safety load circuit breaker thermal overloads or other trip setpoints
 
were 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 definitely
 
established because of incomplete information in the event notification.
 
Att~ehment 2 IN 93-99 December 21, 1993 LIST OF RECENTLY ISSUED
 
NRC INFORMATION NOTICES
 
Information                                  Date of
 
Notice No.            Subject                Issuance  Issued to
 
93-98          Motor Brakes on Valve          12/20/93  All holders of OLs and CPs
 
Actuator Motors                          for nuclear power reactors.
 
93-97          Failures of Yokes              12/17/93  All holders of OLs or CPs
 
Installed on Walworth                    for nuclear power reactors.
 
Gate and Globe Valves
 
93-96          Improper Reset Causes          12/14/93  All holders of OLs or CPs
 
Emergency Diesel                          for nuclear power reactors.
 
Generator Failures
 
93-95          Storm-Related Loss of          12/13/93  All holders of OLs or CPs
 
Offsite Power Events                      for nuclear power reactors
 
due to Salt Buildup                      located close to a large
 
on Switchyard Insulators                  body of salt water.
 
93-94          Unauthorized Forced            12/09/93  All holders of OLs or CPs
 
Entry into the Pro-                      for nuclear power reactors.
 
tected Area at Three
 
Mile Island Unit 1 on
 
February 7, 1993
93-93          Inadequate Control of          12/08/93  All holders of OLs or CPs
 
Reactor Coolant System                    for nuclear power reactors.
 
Conditions During Shutdown
 
93-92          Plant Improvements to          12/07/93  All holders of OLs or CPs
 
Mitigate Common Depend-                  for nuclear power reactors.
 
encies in Component
 
Cooling Water Systems
 
91-21,        Inadequate Quality            12/07/93  All holders of OLs or CPs
 
Supp. 1        Assurance Program of                      for nuclear power reactors
 
Vendor Supplying                          and all recipients of
 
Safety-Related Equipment                  NUREG-0040, 'License Con- tractor and Vendor Inspec- tion Status ReportR (White
 
Book)..
 
OL - Operating License
 
CP = Construction Permit
 
IN 93-99 December 21, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact listed below or the appropriate Office of Nuclear
 
Reactor Regulation (NRR) project manager.
 
Odginal signed by
 
Brian K.Grimes
 
Brian K. Grimes, Director
 
Division of Operating Reactor Support
 
Office of Nuclear Reactor Regulation
 
Technical contact:  C. Morris, NRR
 
(301) 504-2778 Attachments:
1. Representative List of Undervoltage
 
Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices
 
E  plion:
The stress laid by the initial reviewer on the degree of concern that
 
licensees and the staff should feel for such a widespread and persistent
 
preblem, viz. low UVR set points, has been all but eliminated from the
 
present IN.
 
*C.MORRIS (S/D)    (SEE PREVIOUS CONC.)
                                15 NOV. 93
*SEE PREVIOUS CONCURRENCES
 
*DO RS/OGCB
 
* C/OGCB:DORS:NRR D/DORS:NRR
 
NCampbell        GHMarcus
 
07/30/93        08/10/93            12//$193
*EELB:DE:NRR    *SC/EELB:DE:NRR      *C/EELB:DE:NRR      *D/DE: NRR      *RPB:ADM
 
CMorris        EWWeiss              CHBerlinger          JTWiggins        Tech Ed
 
04/28/93        95/19/93            05/19/93            07/23/93        07/13/93
# Concurred in electronically by JMain.
 
DOC NAME: 93-99.IN
 
IN 93-XX
 
November XX, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact 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 contact:  C. Morris, NRR
 
(301) 504-2778 Attachments:
    1. Representative List of Undervoltage
 
Relay Setpoint Revisions 1988-1993
    2. List of Recently Issued NRC Information Notices
 
Exception:
      The stress laid by the initial reviewer on the degree of concern that
 
licensees and the staff should feel for such a widespread and persistent
 
problem, viz. low UVR set points, has been all but eliminated from the
 
present IN.                                G4'
                                              C.MORRIS
 
15 NOV. 93 Document Name:  G:\SHARED\R3UNRELS.IN
 
*SEE PREVIOUS CONCURRENCES    # Concurred in electronically by JMain.
 
D/DORS:NRR    *C/OGCB: DORS:NRR *OGCB:DORS:NRR
 
BKGrimes        GHMarcus          NCampbell
 
11/ /93 A      08/10/93          07/30/93
    *EELB:DE:NRR *SC/EELB:DE:NRR  *C/EELB:DE:NRR  *D/DE:NRR          *RPB:ADM
 
CMorris        EWWeiss        CHBerlinger    JTWiggins          Tech Ed
 
04/28/93      05/19/93        05/19/93        07/23/93          07/13/93
&Wp:    4    & Lso1
 
IN 93-XX
 
November XX, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact 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 contact:  C. Morris, NRR
 
(301) 504-2778 Attachments:
1. Representative List of Undervoltage
 
Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices
 
Document Name:  G:\SHARED\R3UNRELS.IN
 
*SEE PREVIOUS CONCURRENCES    # Concurred in electronically by JMain.
 
D/DORS:NRR    *C/OGCB:DWRS:NRR *OGCB: DORS:NRR
 
BKGrimes      GHMarcus          NCampbell
 
ll/ /93        08/10/93          07/30/93
*EELB:DE:NRR  *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR          *RPB:ADM
 
CMorris      EWWeiss        CHBerlinger    JTWiggins          Tech Ed
 
04/28/93      05/19/93        05/19/93      07/23/93          07/13/93
 
IN 93-XX
 
August XX, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact 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 contact:  C. Morris, NRR
 
(301) 504-2778 Attachments:
1. Representative List of Undervoltage
 
Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices
 
*SEE PREVIOUS CONCURRENCES
 
Document Name: UNRELSET.IN          DORS/OGCB  D/DORS:        C/OGCB: DORS:NRR
 
NCampbell  BKGrime        GHMarcus6#/W
 
07/30/93    08/ /93        08/to /93
*EELB:DE:NRR  *SC/EELB:DE:NRR    *C/EELB:DE:NRR    *D/DE :NRR        *RPB:ADM
 
CMorris        EWWeiss            CHBerlinger      JTWiggins        Tech Ed
 
04/28/93      05/19/93            05/19/93          07/23/93          07/13/93
# Concurred in electronically by JMain.
 
IN 93-XX
 
August XX, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact listed below or the appropriate Office of Nuclear
 
Reactor Regulation (NRR) project manager.
 
Brian K. Grimes, Director
 
Division of Operational Events
 
Assessment
 
Office of Nuclear Reactor Regulation
 
Technical contact:  C. Morris, NRR
 
(301) 504-2778 Attachments:
1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices
 
*SEE PREVIOUS CONCURRENCES
 
Document Name: UNRELSET.IN          DRS/OGCB    D/DORS:NRR  C/OGCB:DORS:NRR
 
NCampbell    BKGrimes      GHMarcus
 
07/8* /93    07/ /93        07/ /93
*EELB:DE:NRR  *SC/EELB:DE:NRR    *C/EELB:DE:NRR    *D/DE:NRR      *RPB:ADM
 
CMorris        EWWeiss            CHBerlinger        JTWiggins      Tech Ed
 
04/28/93      05/19/93            05/19/93          07/23/93        07/13/93
# Concurred in electronically by JMain.
 
_>                              K_> IN 93-XX
 
July XX, 1993 This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact listed below or the appropriate Office of Nuclear
 
Reactor Regulation (NRR) project manager.
 
Brian K. Grimes, Director
 
Division of Operational Events
 
Assessment


--"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
Office of Nuclear Reactor Regulation


===Attachments:===
Technical contact: C. Morris, NRR
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:===
(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
1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices


* 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
*SEE PREVIOUS CONCURRENCES


===Attachments:===
Document Name: UNRELSET.IN         DORS/OGCB   D/DORS:NRR
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:===
NCampbell  BIKGrimes      Marcus
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:===
07/ /93    0,7/ /24        T/ /93
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
*EELB:DE:NRR  *SC/EELB:DE:NRR    *C/EELB:DE:NRR                  *RPB:ADM


===Attachments:===
CMorris        EWWeiss            CHBerlinger                      Tech Ed
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:===
04/28/93       05/19/93           05/19/93                         07/13/93
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.}}
# Concurred in electronically by JMain.}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Latest revision as of 04:27, 24 November 2019

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  Entergy icon.png
Issue date: 12/21/1993
From: Grimes B
Office of Nuclear Reactor Regulation
To:
References
IN-93-099, NUDOCS 9312150073
Download: ML031060586 (12)
v • d • e


UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 December 21, 1993 NRC INFORMATION NOTICE 93-99: UNDERVOLTAGE RELAY AND THERMAL OVERLOAD

SETPOINT PROBLEMS

Addressees

All holders of operating licenses or construction permits for nuclear power

plants.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information

notice to alert addressees to continuing discoveries of undervoltage relay and

thermal overload setpoints that are set too low. 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.

Background

In August 1976, the NRC wrote generic letters to all LWR licensees regarding

the need for licensees to evaluate any generic implications of several events

at the Millstone site involving episodes of sustained degraded grid voltage.

On June 2, 1977, as part of multiplant action MPA-23, the staff stated its

position that all licensees must have a second level of undervoltage

protection with a time delay. (During degraded grid voltage episodes, undervoltage relays and thermal overload protective relays protect the safety

equipment.) In a generic letter dated August 8, 1979, the NRC requested all

licensees to determine the capability of the offsite power system to operate

all required loads within their voltage ratings under all conditions within

their design basis. The licensees reviewed their undervoltage relay setpoints

on each of these occasions. In 1981, the NRC issued Branch Technical

Position, Power System Branch-1, "Adequacy of Station Electric Distribution

System Voltages," which discussed, among other things, the addition of a

second undervoltage relay with an associated time delay. Between 1981 and

1992, the NRC issued two information notices, in which it discussed

undervoltage relay setpoints and other concerns:

1. IN 84-02, "Operating a Nuclear Power Plant at Voltage

Levels Lower than Analyzed," issued January 10, 1984.

2. IN 91-29, "Deficiencies Identified During Electrical Distribution

System Functional Inspections," issued April 15, 1991.

9312150073 PDR E No4tEC 93-0 1 e ' , t

IN 93-99 December 21, 1993 3. IN 91-29, Supplement 1, TDeficiencies Identified During

-- 93-99

"VIN

December 21, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Bran K. rimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

Attachment 1 IN 93-99 December 21, 1993 Representative List of Undervoltaqe Relay Set Point Revision Notifications and

Technical Specification Change Proposals for 1988-1993 Event Notification Licensee Event Notification Date

Number

11374 Pilgrim 1 January 30, 1988 1

14043 Pilgrim 1 November 18, 1988 5

00000 Pilgrim 1 June 30, 1988 1

14780 Cooper 1 February 17, 1989 5

16540 Crystal River 3 September 8, 1989 1

17121 Robinson 2 November 16, 1989 1

18322 Oconee 1, 2 and 3 April 24, 1990 5

18466 McGuire 1 and 2 May 14, 1990 1

18892 St. Lucie 2 July 14, 1990 2

19023 Haddam Neck 1 August 2, 1990 5

20021 Calvert Cliff 1 and 2 December 6, 1990 1

20435 Ft. Calhoun February 12, 1991 1

20503 Kewaunee 1 February 20, 1991 5

20542 Salem 2 February 27, 1991 2

21691 Dresden 2 and 3 August 23, 1991 5

22281 Dresden 2 November 20, 1991 1

22498 Zion 1 and 2 December 19, 1991 5

22580 Indian Point 3 January 9, 1992

22658 Dresden 3 January 22, 1992

22847 (TOL) Washington Nuclear 2 February 19, 1992

22918 Washington Nuclear 2 March 1, 1992

23148 Vermont Yankee April 1, 1992

23191 Quad Cities 1 and 2 April 7, 1992

23338 LaSalle 1 and 2 April 27, 1992

23365 LaSalle 2 April 29, 1992

23385 Crystal River 3 May 1, 1992

23439 (TOL) Grand Gulf May 11, 1992

23452 Comanche Peak 2 May 13, 1992

23576 Crystal River 3 June 4, 1992

23784 Zion 1 and 2 July 2, 1992

23932 Byron 1 and 2 July 24, 1992

00000 Callaway July 23, 1992

24229 Crystal River 3 September 14, 1992

24384 Dresden 2 and 3 October 6, 1992

  • TOL - Thermal Overload

Attachment 1 IN 93-99 December 21, 1993 Event Notification Licensee Event Notification Date Class

Number

00000 Prairie Island 1 & 2 November 6, 1992 1

00000 St. Lucie 1 November 30, 1992 1

24757 Maine Yankee December 15, 1992 5

00000 Diablo Canyon 1 and 2 December 22, 1992 1

24845 Point Beach 1 and 2 January 7, 1993 1

25248 (TOL) Pilgrim March 29, 1993 5

25362 South Texas April 6, 1993 5 Events Notification Number-00000 Licensees whose undervoltage relay setpoint

notifications to the NRC were reported by LERs, licensee letter, etc., and

event notification numbers if any, were not known.

Class Definitions:

1. Undervoltage Relay setpoints were found to be incorrect because of

design errors.

2. Undervoltage Relay setpoints, as found, were not the same as required by

the technical specification.

3. Safety load circuit breaker thermal overloads or other trip setpoints

were 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 definitely

established because of incomplete information in the event notification.

Att~ehment 2 IN 93-99 December 21, 1993 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

93-98 Motor Brakes on Valve 12/20/93 All holders of OLs and CPs

Actuator Motors for nuclear power reactors.

93-97 Failures of Yokes 12/17/93 All holders of OLs or CPs

Installed on Walworth for nuclear power reactors.

Gate and Globe Valves

93-96 Improper Reset Causes 12/14/93 All holders of OLs or CPs

Emergency Diesel for nuclear power reactors.

Generator Failures

93-95 Storm-Related Loss of 12/13/93 All holders of OLs or CPs

Offsite Power Events for nuclear power reactors

due to Salt Buildup located close to a large

on Switchyard Insulators body of salt water.

93-94 Unauthorized Forced 12/09/93 All holders of OLs or CPs

Entry into the Pro- for nuclear power reactors.

tected Area at Three

Mile Island Unit 1 on

February 7, 1993

93-93 Inadequate Control of 12/08/93 All holders of OLs or CPs

Reactor Coolant System for nuclear power reactors.

Conditions During Shutdown

93-92 Plant Improvements to 12/07/93 All holders of OLs or CPs

Mitigate Common Depend- for nuclear power reactors.

encies in Component

Cooling Water Systems

91-21, Inadequate Quality 12/07/93 All holders of OLs or CPs

Supp. 1 Assurance Program of for nuclear power reactors

Vendor Supplying and all recipients of

Safety-Related Equipment NUREG-0040, 'License Con- tractor and Vendor Inspec- tion Status ReportR (White

Book)..

OL - Operating License

CP = Construction Permit

IN 93-99 December 21, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Odginal signed by

Brian K.Grimes

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

E plion:

The stress laid by the initial reviewer on the degree of concern that

licensees and the staff should feel for such a widespread and persistent

preblem, viz. low UVR set points, has been all but eliminated from the

present IN.

  • C.MORRIS (S/D) (SEE PREVIOUS CONC.)

15 NOV. 93

  • SEE PREVIOUS CONCURRENCES
  • DO RS/OGCB
  • C/OGCB:DORS:NRR D/DORS:NRR

NCampbell GHMarcus

07/30/93 08/10/93 12//$193

  • EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE: NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 95/19/93 05/19/93 07/23/93 07/13/93

  1. Concurred in electronically by JMain.

DOC NAME: 93-99.IN

IN 93-XX

November XX, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact 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 contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

Exception:

The stress laid by the initial reviewer on the degree of concern that

licensees and the staff should feel for such a widespread and persistent

problem, viz. low UVR set points, has been all but eliminated from the

present IN. G4'

C.MORRIS

15 NOV. 93 Document Name: G:\SHARED\R3UNRELS.IN

  • SEE PREVIOUS CONCURRENCES # Concurred in electronically by JMain.

D/DORS:NRR *C/OGCB: DORS:NRR *OGCB:DORS:NRR

BKGrimes GHMarcus NCampbell

11/ /93 A 08/10/93 07/30/93

  • EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

&Wp: 4 & Lso1

IN 93-XX

November XX, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact 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 contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

Document Name: G:\SHARED\R3UNRELS.IN

  • SEE PREVIOUS CONCURRENCES # Concurred in electronically by JMain.

D/DORS:NRR *C/OGCB:DWRS:NRR *OGCB: DORS:NRR

BKGrimes GHMarcus NCampbell

ll/ /93 08/10/93 07/30/93

  • EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

IN 93-XX

August XX, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact 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 contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage

Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCES

Document Name: UNRELSET.IN DORS/OGCB D/DORS: C/OGCB: DORS:NRR

NCampbell BKGrime GHMarcus6#/W

07/30/93 08/ /93 08/to /93

  • EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE :NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

  1. Concurred in electronically by JMain.

IN 93-XX

August XX, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operational Events

Assessment

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCES

Document Name: UNRELSET.IN DRS/OGCB D/DORS:NRR C/OGCB:DORS:NRR

NCampbell BKGrimes GHMarcus

07/8* /93 07/ /93 07/ /93

  • EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger JTWiggins Tech Ed

04/28/93 05/19/93 05/19/93 07/23/93 07/13/93

  1. Concurred in electronically by JMain.

_> K_> IN 93-XX

July XX, 1993 This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Brian K. Grimes, Director

Division of Operational Events

Assessment

Office of Nuclear Reactor Regulation

Technical contact: C. Morris, NRR

(301) 504-2778 Attachments:

1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993

2. List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCES

Document Name: UNRELSET.IN DORS/OGCB D/DORS:NRR

NCampbell BIKGrimes Marcus

07/ /93 0,7/ /24 T/ /93

  • EELB:DE:NRR *SC/EELB:DE:NRR *C/EELB:DE:NRR *RPB:ADM

CMorris EWWeiss CHBerlinger Tech Ed

04/28/93 05/19/93 05/19/93 07/13/93

  1. Concurred in electronically by JMain.


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