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

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{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY
{{#Wiki_filter:UNITED STATES


COMMISSION
NUCLEAR REGULATORY COMMISSION


===OFFICE OF NUCLEAR REACTOR REGULATION===
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 December 21, 1993 NRC INFORMATION


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


RELAY AND THERMAL OVERLOAD SETPOINT PROBLEMS
SETPOINT PROBLEMS


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


licenses or construction
plants.
 
permits for nuclear power plants.


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


Commission (NRC) is issuing this information
notice to alert addressees to continuing discoveries of undervoltage relay and


notice to alert addressees
thermal overload setpoints that are set too low. It is expected that


to continuing
recipients will review the information for applicability to their facilities


discoveries
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.


of undervoltage
Background


relay and thermal overload setpoints
In August 1976, the NRC wrote generic letters to all LWR licensees regarding


that are set too low. It is expected that recipients
the need for licensees to evaluate any generic implications of several events


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


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


to their facilities
position that all licensees must have a second level of undervoltage


and consider actions, as appropriate, to avoid similar problems.
protection with a time delay. (During degraded grid voltage episodes, undervoltage relays and thermal overload protective relays protect the safety


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


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


in this Information
all required loads within their voltage ratings under all conditions within


notice are not NRC requirements;
their design basis. The licensees reviewed their undervoltage relay setpoints
therefore, no specific action or written response is required.Background


In August 1976, the NRC wrote generic letters to all LWR licensees
on each of these occasions. In 1981, the NRC issued Branch Technical


regarding the need for licensees
Position, Power System Branch-1, "Adequacy of Station Electric Distribution


to evaluate any generic implications
System Voltages," which discussed, among other things, the addition of a


of several events at the Millstone
second undervoltage relay with an associated time delay. Between 1981 and


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


episodes of sustained
undervoltage relay setpoints and other concerns:
      1. IN 84-02, "Operating a Nuclear Power Plant at Voltage


degraded grid voltage.On June 2, 1977, as part of multiplant
Levels Lower than Analyzed," issued January 10, 1984.


action MPA-23, the staff stated its position that all licensees
2. IN 91-29, "Deficiencies Identified During Electrical Distribution


must have a second level of undervoltage
System Functional Inspections," issued April 15, 1991.


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


with a time delay. (During degraded grid voltage episodes, undervoltage
IN 93-99 December 21, 1993 3. IN 91-29, Supplement 1, TDeficiencies Identified During


relays and thermal overload protective
--  93-99
                                                            "VIN


relays protect the safety equipment.)
December 21, 1993 This information notice requires no specific action or written response. If
In a generic letter dated August 8, 1979, the NRC requested


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


to determine
the technical contact listed below or the appropriate Office of Nuclear


the capability
Reactor Regulation (NRR) project manager.


of the offsite power system to operate all required loads within their voltage ratings under all conditions
Bran K. rimes, Director


within their design basis. The licensees
Division of Operating Reactor Support


reviewed their undervoltage
Office of Nuclear Reactor Regulation


relay setpoints on each of these occasions.
Technical contact:  C. Morris, NRR


In 1981, the NRC issued Branch Technical Position, Power System Branch-1, "Adequacy
(301) 504-2778 Attachments:
1. Representative List of Undervoltage


of Station Electric Distribution
Relay Setpoint Revisions 1988-1993
2.  List of Recently Issued NRC Information Notices


System Voltages," which discussed, among other things, the addition of a second undervoltage
Attachment 1 IN 93-99 December 21, 1993 Representative List of Undervoltaqe Relay Set Point Revision Notifications and


relay with an associated
Technical Specification Change Proposals for 1988-1993 Event Notification  Licensee                Event Notification Date


time delay. Between 1981 and 1992, the NRC issued two information
Number


notices, in which it discussed undervoltage
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


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


and other concerns: 1. IN 84-02, "Operating
Number


a Nuclear Power Plant at Voltage Levels Lower than Analyzed," issued January 10, 1984.2. IN 91-29, "Deficiencies
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


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


During Electrical
event notification numbers if any, were not known.


===Distribution===
Class Definitions:
System Functional
1.    Undervoltage Relay setpoints were found to be incorrect because of


Inspections," issued April 15, 1991.9312150073 PDR E No4tEC 93-0 1 e ' , t
design errors.


IN 93-99 December 21, 1993 3. IN 91-29, Supplement
2.    Undervoltage Relay setpoints, as found, were not the same as required by


1, TDeficiencies
the technical specification.


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


During
were too low because of design errors.


--"VIN 93-99 December 21, 1993 This information
4.    Safety load circuit breaker thermal overload, or other trip setpoints, as found, were not the same as required by the technical specification.


notice requires no specific action or written response.
5.   Membership in one of the preceding four classes could not be definitely


If you have any questions
established because of incomplete information in the event notification.


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


in this notice, please contact the technical
NRC INFORMATION NOTICES


contact listed below or the appropriate
Information                                  Date of


Office of Nuclear Reactor Regulation (NRR) project manager.Bran K. rimes, Director Division of Operating
Notice No.             Subject                Issuance  Issued to


===Reactor Support Office of Nuclear Reactor Regulation===
93-98          Motor Brakes on Valve          12/20/93  All holders of OLs and CPs
Technical


contact: C. Morris, NRR (301) 504-2778 Attachments:
Actuator Motors                          for nuclear power reactors.
1. Representative


===List of Undervoltage===
93-97          Failures of Yokes              12/17/93  All holders of OLs or CPs
Relay Setpoint Revisions


1988-1993 2. List of Recently Issued NRC Information
Installed on Walworth                    for nuclear power reactors.


Notices
Gate and Globe Valves


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


1 IN 93-99 December 21, 1993 Representative
Emergency Diesel                          for nuclear power reactors.


List of Undervoltaqe
Generator Failures


Relay Set Point Revision Notifications
93-95          Storm-Related Loss of          12/13/93  All holders of OLs or CPs


and Technical
Offsite Power Events                      for nuclear power reactors


Specification
due to Salt Buildup                      located close to a large


Change Proposals
on Switchyard Insulators                  body of salt water.


for 1988-1993 Event Notification
93-94          Unauthorized Forced            12/09/93  All holders of OLs or CPs


Number Licensee Event Notification
Entry into the Pro-                      for nuclear power reactors.


Date 11374 14043 00000 14780 16540 17121 Pilgrim Pilgrim Pilgrim 1 1 1 January 30, 1988 November 18, 1988 June 30, 1988 1 5 1 Cooper 1 Crystal River 3 Robinson 2 February 17, September
tected Area at Three


8, November 16, 1989 1989 1989 5 1 1 18322 18466 18892 19023 20021 Oconee 1, 2 and 3 McGuire 1 and 2 St. Lucie 2 Haddam Neck 1 Calvert Cliff 1 and 2 Ft. Calhoun Kewaunee 1 Salem 2 Dresden 2 and 3 Dresden 2 Zion 1 and 2 April 24, 1990 May 14, 1990 July 14, 1990 August 2, 1990 December 6, 1990 February 12, 1991 February 20, 1991 February 27, 1991 August 23, 1991 November 20, 1991 December 19, 1991 5 1 2 5 1 20435 20503 20542 21691 22281 22498 1 5 2 5 1 5 22580 22658 22847 (TOL)22918 23148 23191 23338 23365 23385 23439 (TOL)23452 23576 23784 23932 00000 24229 24384 Indian Point 3 Dresden 3 Washington
Mile Island Unit 1 on


Nuclear 2 Washington
February 7, 1993
93-93          Inadequate Control of          12/08/93  All holders of OLs or CPs


Nuclear 2 Vermont Yankee Quad Cities 1 and 2 LaSalle 1 and 2 LaSalle 2 Crystal River 3 Grand Gulf Comanche Peak 2 Crystal River 3 Zion 1 and 2 Byron 1 and 2 Callaway Crystal River 3 Dresden 2 and 3 January 9, 1992 January 22, 1992 February 19, 1992 March 1, 1992 April 1, 1992 April 7, 1992 April 27, 1992 April 29, 1992 May 1, 1992 May 11, 1992 May 13, 1992 June 4, 1992 July 2, 1992 July 24, 1992 July 23, 1992 September
Reactor Coolant System                    for nuclear power reactors.


14, 1992 October 6, 1992*TOL -Thermal Overload
Conditions During Shutdown


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


1 IN 93-99 December 21, 1993 Event Notification
Mitigate Common Depend-                   for nuclear power reactors.


Licensee Event Notification
encies in Component


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
Cooling Water Systems


Number-00000
91-21,        Inadequate Quality            12/07/93  All holders of OLs or CPs
Licensees


whose undervoltage
Supp. 1        Assurance Program of                      for nuclear power reactors


relay setpoint notifications
Vendor Supplying                          and all recipients of


to the NRC were reported by LERs, licensee letter, etc., and event notification
Safety-Related Equipment                  NUREG-0040, 'License Con- tractor and Vendor Inspec- tion Status ReportR (White


numbers if any, were not known.Class Definitions:
Book)..
1. Undervoltage


Relay setpoints
OL - Operating License


were found to be incorrect
CP = Construction Permit


because of design errors.2. Undervoltage
IN 93-99 December 21, 1993 This information notice requires no specific action or written response. If


Relay setpoints, as found, were not the same as required by the technical
you have any questions about the information in this notice, please contact


specification.
the technical contact listed below or the appropriate Office of Nuclear


3. Safety load circuit breaker thermal overloads
Reactor Regulation (NRR) project manager.


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
Odginal signed by


specification.
Brian K.Grimes


5. Membership
Brian K. Grimes, Director


in one of the preceding
Division of Operating Reactor Support


four classes could not be definitely
Office of Nuclear Reactor Regulation


established
Technical contact:  C. Morris, NRR


because of incomplete
(301) 504-2778 Attachments:
1. Representative List of Undervoltage


information
Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices


in the event notification.
E  plion:
The stress laid by the initial reviewer on the degree of concern that


Att~ehment
licensees and the staff should feel for such a widespread and persistent


2 IN 93-99 December 21, 1993 LIST OF RECENTLY ISSUED NRC INFORMATION
preblem, viz. low UVR set points, has been all but eliminated from the


NOTICES Information
present IN.


Date of Notice No. Subject Issuance Issued to 93-98 93-97 93-96 93-95 93-94 93-93 Motor Brakes on Valve Actuator Motors Failures of Yokes Installed
*C.MORRIS (S/D)    (SEE PREVIOUS CONC.)
                                15 NOV. 93
*SEE PREVIOUS CONCURRENCES


on Walworth Gate and Globe Valves Improper Reset Causes Emergency
*DO RS/OGCB


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


Failures Storm-Related
NCampbell        GHMarcus


Loss of Offsite Power Events due to Salt Buildup on Switchyard
07/30/93        08/10/93            12//$193
*EELB:DE:NRR    *SC/EELB:DE:NRR      *C/EELB:DE:NRR      *D/DE: NRR      *RPB:ADM


Insulators
CMorris        EWWeiss              CHBerlinger          JTWiggins        Tech Ed


Unauthorized
04/28/93        95/19/93            05/19/93            07/23/93        07/13/93
# Concurred in electronically by JMain.


Forced Entry into the Pro-tected Area at Three Mile Island Unit 1 on February 7, 1993 Inadequate
DOC NAME: 93-99.IN


Control of Reactor Coolant System Conditions
IN 93-XX


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


to Mitigate Common Depend-encies in Component Cooling Water Systems Inadequate
you have any questions about the information in this notice, please contact


Quality Assurance
the technical contact listed below or the appropriate Office of Nuclear


Program of Vendor Supplying Safety-Related
Reactor Regulation (NRR) project manager.


Equipment 12/20/93 12/17/93 12/14/93 12/13/93 12/09/93 12/08/93 12/07/93 12/07/93 All holders of OLs and CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors located close to a large body of salt water.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors and all recipients
Brian K. Grimes, Director


of NUREG-0040, 'License Con-tractor and Vendor Inspec-tion Status ReportR (White Book)..93-92 91-21, Supp. 1 OL -Operating
Division of Operating Reactor Support


License CP = Construction
Office of Nuclear Reactor Regulation


Permit
Technical contact:  C. Morris, NRR


IN 93-99 December 21, 1993 This information
(301) 504-2778 Attachments:
    1. Representative List of Undervoltage


notice requires no specific action or written response.
Relay Setpoint Revisions 1988-1993
    2. List of Recently Issued NRC Information Notices


If you have any questions
Exception:
      The stress laid by the initial reviewer on the degree of concern that


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


in this notice, please contact the technical
problem, viz. low UVR set points, has been all but eliminated from the


contact listed below or the appropriate
present IN.                                G4'
                                              C.MORRIS


Office of Nuclear Reactor Regulation (NRR) project manager.Odginal signed by Brian K. Grimes Brian K. Grimes, Director Division of Operating
15 NOV. 93 Document Name:  G:\SHARED\R3UNRELS.IN


===Reactor Support Office of Nuclear Reactor Regulation===
*SEE PREVIOUS CONCURRENCES    # Concurred in electronically by JMain.
Technical


contact: C. Morris, NRR (301) 504-2778 Attachments:
D/DORS:NRR    *C/OGCB: DORS:NRR *OGCB:DORS:NRR
1. Representative


===List of Undervoltage===
BKGrimes        GHMarcus          NCampbell
Relay Setpoint Revisions


1988-1993 2. List of Recently Issued NRC Information
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


Notices E plion: The stress laid by the initial reviewer on the licensees
CMorris        EWWeiss        CHBerlinger    JTWiggins          Tech Ed


and the staff should feel for such a preblem, viz. low UVR set points, has been all present IN.degree of concern that widespread
04/28/93      05/19/93        05/19/93        07/23/93          07/13/93
&Wp:    4    & Lso1


and persistent
IN 93-XX


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


from the (SEE PREVIOUS CONC.)*C.MORRIS 15 NOV. 93 (S/D)*SEE PREVIOUS CONCURRENCES
you have any questions about the information in this notice, please contact


*DO RS/OGCB
the technical contact listed below or the appropriate Office of Nuclear


* C/OGCB:DORS:NRR
Reactor Regulation (NRR) project manager.


D/DORS:NRR
Brian K. Grimes, Director


NCampbell
Division of Operating Reactor Support


GHMarcus 07/30/93 08/10/93 12//$193*EELB:DE:NRR
Office of Nuclear Reactor Regulation


CMorris 04/28/93*SC/EELB:DE:NRR
Technical contact: C. Morris, NRR


EWWeiss 95/19/93*C/EELB:DE:NRR
(301) 504-2778 Attachments:
1. Representative List of Undervoltage


CHBerlinger
Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices


05/19/93*D/DE: NRR JTWiggins 07/23/93*RPB:ADM Tech Ed 07/13/93# Concurred
Document Name: G:\SHARED\R3UNRELS.IN


in electronically
*SEE PREVIOUS CONCURRENCES    # Concurred in electronically by JMain.


by JMain.DOC NAME: 93-99.IN
D/DORS:NRR    *C/OGCB:DWRS:NRR *OGCB: DORS:NRR


IN 93-XX November XX, 1993 This information
BKGrimes      GHMarcus          NCampbell


notice requires no specific action or written response.
ll/ /93        08/10/93          07/30/93
*EELB:DE:NRR  *SC/EELB:DE:NRR *C/EELB:DE:NRR *D/DE:NRR          *RPB:ADM


If you have any questions
CMorris      EWWeiss        CHBerlinger    JTWiggins          Tech Ed


about the information
04/28/93      05/19/93        05/19/93      07/23/93          07/13/93


in this notice, please contact the technical
IN 93-XX


contact listed below or the appropriate
August XX, 1993 This information notice requires no specific action or written response. If


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
you have any questions about the information in this notice, please contact


===Reactor Support Office of Nuclear Reactor Regulation===
the technical contact listed below or the appropriate Office of Nuclear
Technical


contact: C. Morris, NRR (301) 504-2778 Attachments:
Reactor Regulation (NRR) project manager.
1. Representative


===List of Undervoltage===
Brian K. Grimes, Director
Relay Setpoint Revisions


1988-1993 2. List of Recently Issued NRC Information
Division of Operating Reactor Support


Notices Exception:
Office of Nuclear Reactor Regulation
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
Technical contact:  C. Morris, NRR


problem, viz. low UVR set points, has been all but eliminated
(301) 504-2778 Attachments:
1. Representative List of Undervoltage


from the present IN. G4'C.MORRIS 15 NOV. 93 Document Name: G:\SHARED\R3UNRELS.IN
Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices


*SEE PREVIOUS CONCURRENCES
*SEE PREVIOUS CONCURRENCES


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


in electronically
NCampbell  BKGrime        GHMarcus6#/W


by D/DORS:NRR
07/30/93    08/ /93        08/to /93
*EELB:DE:NRR  *SC/EELB:DE:NRR    *C/EELB:DE:NRR    *D/DE :NRR       *RPB:ADM


*C/OGCB: DORS:NRR BKGrimes GHMarcus 11/ /93 A 08/10/93*C/EELB:DE:NRR
CMorris        EWWeiss            CHBerlinger      JTWiggins        Tech Ed


*D/DE:NRR CHBerlinger
04/28/93      05/19/93            05/19/93          07/23/93          07/13/93
# Concurred in electronically by JMain.


JTWiggins 05/19/93 07/23/93 JMain.*OGCB:DORS:NRR
IN 93-XX


NCampbell 07/30/93*RPB:ADM Tech Ed 07/13/93*EELB:DE:NRR
August XX, 1993 This information notice requires no specific action or written response. If


CMorris 04/28/93*SC/EELB:DE:NRR
you have any questions about the information in this notice, please contact


EWWeiss 05/19/93&Wp: & 4 Lso1 IN 93-XX November XX, 1993 This information
the technical contact listed below or the appropriate Office of Nuclear


notice requires no specific action or written response.
Reactor Regulation (NRR) project manager.


If you have any questions
Brian K. Grimes, Director


about the information
Division of Operational Events


in this notice, please contact the technical
Assessment


contact listed below or the appropriate
Office of Nuclear Reactor Regulation


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating
Technical contact:  C. Morris, NRR


===Reactor Support Office of Nuclear Reactor Regulation===
(301) 504-2778 Attachments:
Technical
1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993
 
2. List of Recently Issued NRC Information Notices
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
*SEE PREVIOUS CONCURRENCES


# Concurred
Document Name: UNRELSET.IN         DRS/OGCB     D/DORS:NRR  C/OGCB:DORS:NRR
 
in D/DORS:NRR
 
BKGrimes ll/ /93*C/EELB:DE:NRR
 
CHBerlinger
 
05/19/93 electronically
 
by*C/OGCB:DWRS:NRR
 
GHMarcus 08/10/93*D/DE:NRR JTWiggins 07/23/93 JMain.*OGCB: DORS:NRR NCampbell 07/30/93*RPB:ADM Tech Ed 07/13/93*EELB:DE:NRR
 
CMorris 04/28/93*SC/EELB:DE:NRR
 
EWWeiss 05/19/93 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 NCampbell 07/30/93 D/DORS: BKGrime 08/ /93 C/OGCB: DORS:NRR GHMarcus6#/W
 
08/to /93*EELB:DE:NRR


CMorris 04/28/93*SC/EELB:DE:NRR
NCampbell    BKGrimes      GHMarcus


EWWeiss 05/19/93*C/EELB:DE:NRR
07/8* /93    07/ /93        07/ /93
*EELB:DE:NRR  *SC/EELB:DE:NRR    *C/EELB:DE:NRR     *D/DE:NRR      *RPB:ADM


CHBerlinger
CMorris        EWWeiss            CHBerlinger       JTWiggins      Tech Ed


05/19/93*D/DE : NRR JTWiggins 07/23/93*RPB:ADM Tech Ed 07/13/93# Concurred
04/28/93      05/19/93           05/19/93          07/23/93       07/13/93
# Concurred in electronically by JMain.


in electronically
_>                              K_> IN 93-XX


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


IN 93-XX August XX, 1993 This information
you have any questions about the information in this notice, please contact


notice requires no specific action or written response.
the technical contact listed below or the appropriate Office of Nuclear


If you have any questions
Reactor Regulation (NRR) project manager.


about the information
Brian K. Grimes, Director


in this notice, please contact the technical
Division of Operational Events


contact listed below or the appropriate
Assessment


Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operational
===Events Assessment===
Office of Nuclear Reactor Regulation
Office of Nuclear Reactor Regulation


Technical
Technical contact:  C. Morris, NRR


contact: C. Morris, NRR (301) 504-2778 Attachments:
(301) 504-2778 Attachments:
1. Representative
1. Representative List of Undervoltage Relay Setpoint Revisions 1988-1993
2. List of Recently Issued NRC Information Notices


List of Undervoltage
*SEE PREVIOUS CONCURRENCES
 
Relay Setpoint Revisions
 
1988-1993 2. List of Recently Issued NRC Information
 
Notices*SEE PREVIOUS CONCURRENCES
 
Document Name: UNRELSET.IN
 
DRS/OGCB NCampbell 07/8* /93 D/DORS:NRR
 
BKGrimes 07/ /93 C/OGCB:DORS:NRR
 
GHMarcus 07/ /93*EELB:DE:NRR
 
CMorris 04/28/93*SC/EELB:DE:NRR
 
EWWeiss 05/19/93*C/EELB:DE:NRR
 
CHBerlinger
 
05/19/93*D/DE:NRR JTWiggins 07/23/93*RPB:ADM Tech Ed 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===
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 NCampbell
 
BI 07/ /93 0,*C/EELB:DE:NRR
 
CHBerlinger


05/19/93/DORS:NRR KGrimes 7/ /24*EELB:DE:NRR
Document Name: UNRELSET.IN          DORS/OGCB  D/DORS:NRR


CMorris 04/28/93*SC/EELB:DE:NRR
NCampbell  BIKGrimes      Marcus


EWWeiss 05/19/93 Marcus T/ /93*RPB:ADM Tech Ed 07/13/93# Concurred
07/ /93     0,7/ /24        T/ /93
*EELB:DE:NRR  *SC/EELB:DE:NRR    *C/EELB:DE:NRR                  *RPB:ADM


in electronically
CMorris        EWWeiss            CHBerlinger                      Tech Ed


by JMain.}}
04/28/93      05/19/93            05/19/93                        07/13/93
# 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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