Information Notice 1988-75, Disabling of Diesel Generator Output Circuit Breakers by Anti-Pump Circuitry: Difference between revisions

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| issue date = 09/16/1988
| issue date = 09/16/1988
| title = Disabling of Diesel Generator Output Circuit Breakers by Anti-Pump Circuitry
| title = Disabling of Diesel Generator Output Circuit Breakers by Anti-Pump Circuitry
| author name = Rossi C E
| author name = Rossi C
| author affiliation = NRC/NRR
| author affiliation = NRC/NRR
| addressee name =  
| addressee name =  
Line 14: Line 14:
| page count = 8
| page count = 8
}}
}}
{{#Wiki_filter:I UNITED STATES NUCLEAR REGULATORY
{{#Wiki_filter:I


COMMISSION
UNITED STATES


===OFFICE OF NUCLEAR REACTOR REGULATION===
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555 September


16, 1988 NRC INFORMATION
OFFICE OF NUCLEAR REACTOR REGULATION


NOTICE NO. 88-75: DISABLING
WASHINGTON, D.C. 20555 September 16, 1988 NRC INFORMATION NOTICE NO. 88-75:   DISABLING OF DIESEL GENERATOR OUTPUT


OF DIESEL GENERATOR
CIRCUIT BREAKERS BY ANTI-PUMP CIRCUITRY
 
OUTPUT CIRCUIT BREAKERS BY ANTI-PUMP
 
CIRCUITRY


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


permits for nuclear power reactors.
reactors.


==Purpose==
==Purpose==
: This information
:
  This information notice is being provided to alert addressees to potential


notice is being provided to alert addressees
problems where the capability to either automatically or manually close


to potential problems where the capability
diesel generator circuit breakers from the control room may be lost. It


to either automatically
is expected that recipients will review the information for applicability


or manually close diesel generator
to their facilities and consider actions, as appropriate, to avoid similar


circuit breakers from the control room may be lost. It is expected that recipients
problems. However, suggestions contained in this information notice do not


will review the information
constitute NRC requirements; therefore, no specific action or written response


for applicability
is required.


to their facilities
==Description of Circumstances==
:
  On June 5, 1988, operators at Browns Ferry Unit 3 were unable to reclose the


and consider actions, as appropriate, to avoid similar problems.
diesel generator output breakers to the 4-kV shutdown boards from the control


However, suggestions
room during a loss-of-power/loss-of-coolant-accident (LOP/LOCA) test. During


contained
the test, the output breakers connected the diesel generators to their respec- tive 4-kV shutdown boards after the LOP signal was generated; however, the


in this information
breakers tripped and remained open after receiving the LOCA signal. Operators


notice do not constitute
diagnosed the output breaker lockout problem using system electrical configu- ration drawings. An operator was sent to the 4-kY shutdown board to manually


NRC requirements;
transfer output breaker control power to its alternate source. This momentarily
therefore, no specific action or written response is required.Description


of Circumstances:
removed power, enabling the breaker to close when the power was restored.
On June 5, 1988, operators


at Browns Ferry Unit 3 were unable to reclose the diesel generator
On October 14, 1987, an operator at Wolf Creek Generating Station manually


output breakers to the 4-kV shutdown boards from the control room during a loss-of-power/loss-of-coolant-accident (LOP/LOCA)
tripped the output circuit breaker of the emergency diesel generator (EDG)
test. During the test, the output breakers connected
  from the control room. At the time, the EDG was supplying a vital bus. When


the diesel generators
the operators tried to reenergize the vital bus from the still-operating EDG,
  they found that they could not close the EDG output breaker from the control


to their respec-tive 4-kV shutdown boards after the LOP signal was generated;
room. The vital bus was finally reenergized from the offsite power supply.
however, the breakers tripped and remained open after receiving


the LOCA signal. Operators diagnosed
Through examination of the breaker control schematics the licensee later


the output breaker lockout problem using system electrical
found that the EDG circuit breaker could be closed by cycling the EDG mode


configu-ration drawings.
switch at the EDG local control station.


An operator was sent to the 4-kY shutdown board to manually transfer output breaker control power to its alternate
880920197


source. This momentarily
IN 88-75 September 16, 1988 Discussion:
  The anti-pump circuit configuration will protect large breakers from rapid


removed power, enabling the breaker to close when the power was restored.On October 14, 1987, an operator at Wolf Creek Generating
cycling and, under certain circumstances, will prevent breaker closure. At


Station manually tripped the output circuit breaker of the emergency
Browns Ferry Unit 3, a unique sequence of events, a LOP signal followed within


diesel generator (EDG)from the control room. At the time, the EDG was supplying
6 seconds by a LOCA signal, led to the discovery of a design deficiency of this


a vital bus. When the operators
circuit configuration. Contacts from the undervoltage relay will seal in the


tried to reenergize
breaker anti-pump relay until the undervoltage condition on the 4-kV boards


the vital bus from the still-operating
clears.


EDG, they found that they could not close the EDG output breaker from the control room. The vital bus was finally reenergized
The circuit is designed such that following a LOP, the undervoltage condition


from the offsite power supply.Through examination
must exist for at least 5 seconds and the diesel. must reach rated speed before


of the breaker control schematics
the diesel generator output breaker will close on the bus. Once the breaker


the licensee later found that the EDG circuit breaker could be closed by cycling the EDG mode switch at the EDG local control station.880920197 IN 88-75 September
has closed, the closure spring recharge motor and the breaker anti-pump relay


16, 1988 Discussion:
will be energized. A fully discharged closure spring requires 2 seconds for
The anti-pump


circuit configuration
the spring to be fully recharged. During this 2 second window the anti-pump


will protect large breakers from rapid cycling and, under certain circumstances, will prevent breaker closure. At Browns Ferry Unit 3, a unique sequence of events, a LOP signal followed within 6 seconds by a LOCA signal, led to the discovery
coil will remain energized via contacts sensing spring position, and if an


of a design deficiency
undervoltage condition exists on the 4-kY bus it will seal in and lock open


of this circuit configuration.
the breaker.


Contacts from the undervoltage
During the Browns Ferry event, the EDG output breaker closed 5 seconds after


relay will seal in the breaker anti-pump
the LOP signal, the undervoltage condition was eliminated, and the undervoltage


relay until the undervoltage
relay began its 5 second cycle to reset from the undervoltage condition. About


condition
1.5 seconds 1ater. the.LOCA-signaL-retr-ipped-the-breaker-and-created-another--
undervoltage condition on the 4-kV bus. At this point, because the undervoltage


on the 4-kV boards clears.The circuit is designed such that following
relay had not completed its reset cycle, the undervoltage relay remained in its


a LOP, the undervoltage
undervoltage state. Therefore, the undervoltage relay sealed in the still- energized anti-pump relay because the undervoltage condition occurred before


condition must exist for at least 5 seconds and the diesel. must reach rated speed before the diesel generator
the breaker charging spring was fully charged. Thus, the breaker could not


output breaker will close on the bus. Once the breaker has closed, the closure spring recharge motor and the breaker anti-pump
be closed from the control room either manually or automatically until control


relay will be energized.
power was removed, which deenergized the anti-pump relay.


A fully discharged
The Browns Ferry licensee modified the breaker control logic to prevent the anti- pump relay from sealing in during a LOCA condition by adding a time-delay relay


closure spring requires 2 seconds for the spring to be fully recharged.
in the breaker trip coil circuitry. This relay will be energized by a LOCA


During this 2 second window the anti-pump coil will remain energized
signal and its contact in the anti-pump coil seal-in path will open after a


via contacts sensing spring position, and if an undervoltage
2-to 5-second delay to prevent anti-pump coil seal-in and breaker lockout.


condition
The Wolf Creek EDG output circuit breaker has automatic closing logic to close


exists on the 4-kY bus it will seal in and lock open the breaker.During the Browns Ferry event, the EDG output breaker closed 5 seconds after the LOP signal, the undervoltage
the circuit breaker when the following five permissives are satisfied:
      (1) Both offsite circuit breakers are open'
      (2 The EDG mode switch is in the automatic mode.


condition
(3 Lockout relays are deenergized.


was eliminated, and the undervoltage
(4 A 3-second time delay has elapsed.


relay began its 5 second cycle to reset from the undervoltage
(5) The EDG has reached operating speed and voltage.


condition.
This logic sends a constant close signal to the circuit breaker that keeps the


About 1.5 seconds 1ater. the. LOCA-signaL-retr-ipped-the-breaker-and-created-another--
breaker's internal anti-pump relay energized as long as the logic permissives
undervoltage


condition
are satisfied. The anti-pump relay prevents the circuit breaker from cycling


on the 4-kV bus. At this point, because the undervoltage
if attempts are made to hold the breaker closed against a valid trip signal.


relay had not completed
I',


its reset cycle, the undervoltage
IN 88-75 September 16, 1988 When the Wolf Creek operator manually tripped the EDG output breaker, the auto- matic closing logic permissives remained satisfied. Therefore, the anti-pump


relay remained in its undervoltage
relay remained energized, preventing reclosure of the circuit breaker. Cycling


state. Therefore, the undervoltage
the EDG mode control switch at the local control station allowed the circuit


relay sealed in the still-energized
breaker to reclose by momentarily interrupting the automatic close signal, there- by resetting the anti-pump logic. When the mode switch contact was reclosed by


anti-pump
returning the switch to the "auto' position, the circuit breaker's automatic


relay because the undervoltage
closing logic closed the breaker.


condition
The Wolf Creek licensee modified the EDG breaker control switch located in the


occurred before the breaker charging spring was fully charged. Thus, the breaker could not be closed from the control room either manually or automatically
control room to enable the operator to reclose the EDG circuit breaker from the


until control power was removed, which deenergized
control room. This switch was originally intended only as a means of paralleling


the anti-pump
the EDG with the offsite power supply. With the current modification, the switch


relay.The Browns Ferry licensee modified the breaker control logic to prevent the anti-pump relay from sealing in during a LOCA condition
can be used to reset the anti-pump logic and allow the automatic circuit to re- close the breaker. The modification added a contact that is closed in the "normal"
position and open in the "trip" and "pull to lock" positions of the control switch.


by adding a time-delay
When operators manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt the close circuit and reset the circuit breaker


relay in the breaker trip coil circuitry.
anti-pump relay. If the operator wishes to keep the breaker open, he must put


This relay will be energized
the switch in the "pull to lock" position. Returning the switch to the "normal"
position completes the automatic close circuit and the breaker recloses.


by a LOCA signal and its contact in the anti-pump
It should be noted that although the above discussion has dealt only with EDG


coil seal-in path will open after a 2-to 5-second delay to prevent anti-pump
output- circuit breakers, anti-pump circuit problems could also apply to other


coil seal-in and breaker lockout.The Wolf Creek EDG output circuit breaker has automatic
breakers that use automatic closing logic, such as load-sequencing breakers


closing logic to close the circuit breaker when the following
and offsite supply breakers to the emergency buses.


five permissives
The information herein is being provided as an early notification of a potentially


are satisfied:
significant matter that is still under consideration by the NRC staff. If NRC
(1) Both offsite circuit breakers are open'(2 The EDG mode switch is in the automatic


mode.(3 Lockout relays are deenergized.
evaluation so indicates, specific licensee actions may be requested.


(4 A 3-second time delay has elapsed.(5) The EDG has reached operating
No specific action or written response is required by this information notice.


speed and voltage.This logic sends a constant close signal to the circuit breaker that keeps the breaker's
If you have any questions about this matter, please contact one of the technical


internal anti-pump
contacts listed below or the Regional Administrator of the appropriate regional


relay energized
office.


as long as the logic permissives
Di rector


are satisfied.
Division of Operational Events Assessment


The anti-pump
Office of Nuclear Reactor Regulation
 
relay prevents the circuit breaker from cycling if attempts are made to hold the breaker closed against a valid trip signal.I',
IN 88-75 September


16, 1988 When the Wolf Creek operator manually tripped the EDG output breaker, the auto-matic closing logic permissives
Technical Contacts:  James Lazevnick, NRR


remained satisfied.
(301) 492-0814 Carl Schulten, NRR


Therefore, the anti-pump relay remained energized, preventing
(301) 492-1192 Fred Burrows, NRR


reclosure
(301) 492-0783 Attachment:  List of Recently Issued NRC Information Notices


of the circuit breaker. Cycling the EDG mode control switch at the local control station allowed the circuit breaker to reclose by momentarily
Att"aant


interrupting
IN 88-75 September 16, 1988 Page I of I


the automatic
LIST OF RECENTLY ISSUED


close signal, there-by resetting
NRCINFORMATION NOTICES


the anti-pump
Notice No.    Subject                        Issuance  Issued to


logic. When the mode switch contact was reclosed by returning
88-74          Potentially Inadequate        9/14/88  All holders of OLs


the switch to the "auto' position, the circuit breaker's
Perfornance of ECCSin                    or CPs for Wand


automatic closing logic closed the breaker.The Wolf Creek licensee modified the EDG breaker control switch located in the control room to enable the operator to reclose the EDG circuit breaker from the control room. This switch was originally
PWRs During Recirculation                8&W-designei nuclear


intended only as a means of paralleling
Operation Following a LOCA              power reactors.


the EDG with the offsite power supply. With the current modification, the switch can be used to reset the anti-pump
88-73          Direction-Dependent Leak      9/8/88    All holders of 0Ls


logic and allow the automatic
Characteristics of                      or CPs for nuclear


circuit to re-close the breaker. The modification
Containment Purge Valves                power reactors.


added a contact that is closed in the "normal" position and open in the "trip" and "pull to lock" positions
88-72          Inadequacies in the Design    9/2/88  All holders of OLs


of the control switch.When operators
of dc Motor-Operated Valves            or CPs for nuclear


manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt
power reactors.


the close circuit and reset the circuit breaker anti-pump
88-71          Possible Environmental        9/1/88  All holders of OLs


relay. If the operator wishes to keep the breaker open, he must put the switch in the "pull to lock" position.
Effect of the Reentry                  or CPs for nuclear


Returning
of COSMOS  1900 and                    power reactors, fuel


the switch to the "normal" position completes
Request for Collection                  cycle licensees, of Licensee Radioactivity              and Priority I


the automatic
Measurements Attributed                  material licensees.


close circuit and the breaker recloses.It should be noted that although the above discussion
to That Event


has dealt only with EDG output- circuit breakers, anti-pump
88-70          Check Valve Inservice          8/29/88  All holders of OLs


circuit problems could also apply to other breakers that use automatic
Testing Program                          or CPs for nuclear


closing logic, such as load-sequencing
Deficiencies                            power reactors.


breakers and offsite supply breakers to the emergency
88-69          Movable Contact Finger        8/19/88  All holders of OLs


buses.The information
Binding in HFA Relays                    or CPs for nuclear


herein is being provided as an early notification
Manufactured by General                  power reactors.


of a potentially
Electric (GE)
                          88-48,        Licensee Report of Defective 8/24/88    All holders of OLs


significant
Supplement I  Refurbished Valves                      or CPs for nuclear


matter that is still under consideration
power reactors.


by the NRC staff. If NRC evaluation
88-68          Setpoint Testing of Pres-      8/22/88  All holders of OLs


so indicates, specific licensee actions may be requested.
surizer Safety Valves with              or CPs for nuclear


No specific action or written response is required by this information
Filled Loop Seals Using                  power reactors.


notice.If you have any questions
Hydraulic Assist Devices


about this matter, please contact one of the technical contacts listed below or the Regional Administrator
_
                          88P67-      -P-F    Zfiiairy Fiedeaer Pump  8/Z2j88  All holders of OLs


of the appropriate
Turbine Overspeed Trip                  or CPs for nuclear


regional office.Di rector Division of Operational
Failure                                  power reactors.


===Events Assessment===
OL
Office of Nuclear Reactor Regulation


Technical
* Operating License


Contacts:
CP* Construction Permit
James Lazevnick, NRR (301) 492-0814 Carl Schulten, NRR (301) 492-1192 Fred Burrows, NRR (301) 492-0783 Attachment:
List of Recently Issued NRC Information


Notices
UNITED STATES                                                                                  FIRST CLASS MAIL


Att"aant IN 88-75 September
NUCLEAR REGULATORY COMMISSION                                                                            POSTAGE & FEES PAID


16, 1988 Page I of I LIST OF RECENTLY ISSUED NRC INFORMATION
USNRC


NOTICES Notice No. Subject Issuance 88-74 Potentially
WASHINGTON, D.C. 20555 PERMIT No. 0-57 OFFICIAL BUSINESS


Inadequate
PENALTY FOR PRIVATE USE, $300


9/14/88 Perfornance
IN 88-75 September 16, 1988 When the Wolf Creek operator manually tripped the EDG output breaker, the auto- matic closing logic permissives remained satisfied. Therefore, the anti-pump


of ECCS in PWRs During Recirculation
relay remained energized, preventing reclosure of the circuit breaker. Cycling


Operation
the EDG mode control switch at the local control station allowed the circuit


Following
breaker to reclose by momentarily interrupting the automatic close signal, there- by resetting the anti-pump logic. When the mode switch contact was reclosed by


a LOCA 88-73 Direction-Dependent
returning the switch to the "auto" position, the circuit breaker's automatic


Leak 9/8/88 Characteristics
closing logic closed the breaker.


of Containment
The Wolf Creek licensee modified the EDG breaker control switch located in the


Purge Valves 88-72 Inadequacies
control room to enable the operator to reclose the EDG circuit breaker from the


in the Design 9/2/88 of dc Motor-Operated
control room. This switch was originally intended only as a means of paralleling


Valves 88-71 Possible Environmental
the EDG with the offsite power supply. With the current modification, the switch


9/1/88 Effect of the Reentry of COSMOS 1900 and Request for Collection
can be used to reset the anti-pump logic and allow the automatic circuit to re- close the breaker. The modification added a contact that is closed in the "normal"
position and open in the "trip" and "pull to lock" positions of the control switch.


of Licensee Radioactivity
When operators manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt the close circuit and reset the circuit breaker


Measurements
anti-pump relay. If the operator wishes to keep the breaker open, he must put


Attributed
the switch in the "pull to lock" position. Returning the switch to the "normal"
position completes the automatic close circuit and the breaker recloses.


to That Event 88-70 Check Valve Inservice
It should be noted that although the above discussion has dealt only with EDG


8/29/88 Testing Program Deficiencies
output circuit breakers, anti-pump circuit problems could also apply to other


88-69 Movable Contact Finger 8/19/88 Binding in HFA Relays Manufactured
breakers that use automatic closing logic, such as load-sequencing breakers


by General Electric (GE)88-48, Licensee Report of Defective
and offsite supply breakers to the emergency buses.


8/24/88 Supplement
The information herein is being provided as an early notification of a potentially


I Refurbished
significant matter that is still under consideration by the NRC staff. If NRC


Valves 88-68 Setpoint Testing of Pres- 8/22/88 surizer Safety Valves with Filled Loop Seals Using Hydraulic
evaluation so indicates, specific licensee actions may be requested.


Assist Devices 88P67- -P-F Zfiiairy Fiedeaer Pump 8/Z2j88 Turbine Overspeed
No specific action or written response is required by this information notice.


Trip Failure OL
If you have any questions about this matter, please contact one of the technical


* Operating
contacts listed below or the Regional Administrator of the appropriate regional


License CP
office.


* Construction
Charles E. Rossi, Director


Permit Issued to All holders of OLs or CPs for W and 8&W-designei
Division of Operational Events Assessment


nuclear power reactors.All holders of 0Ls 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, fuel cycle licensees, and Priority I material licensees.
Office of Nuclear Reactor Regulation


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.All holders of OLs or CPs for nuclear power reactors._UNITED STATES NUCLEAR REGULATORY
Technical Contacts:  James Lazevnick, NRR


COMMISSION
(301) 492-0814 Carl Schulten, NRR


WASHINGTON, D.C. 20555 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, $300 FIRST CLASS MAIL POSTAGE & FEES PAID USNRC PERMIT No. 0-57 IN 88-75 September
(301) 492-1192 Fred Burrows, NRR


16, 1988 When the Wolf Creek operator manually tripped the EDG output breaker, the auto-matic closing logic permissives
(301) 492-0783 Attachment: List of Recently Issued    NRC Information Notices


remained satisfied.
*SEE PREVIOUS PAGE FOR CONCURRENCE


Therefore, the anti-pump relay remained energized, preventing
OFC *OEAB            Ed *SL:OEAB


reclosure
*Tech      *C:OEAB *D:DEST  *C:OGCB


of the circuit breaker. Cycling the EDG mode control switch at the local control station allowed the circuit breaker to reclose by momentarily
NAME CSchulten BCalure  PBaranowsky  WLanning LShao    CBerlinger    e    l


interrupting
9/(,f 88 DATE 9/7/88    7/28/88 9/7/88        9/7/88  8/24/88  9/8/88


the automatic
IN 88- September , 1988 the


close signal, there-by resetting
contact was reclosed by returning the switch to the "auto" position.


the anti-pump
circuit breaker's automatic closing logic        closed    the   breaker.


logic. When the mode switch contact was reclosed by returning
in the


the switch to the "auto" position, the circuit breaker's
The Wolf Creek licensee modified the EDG breaker control switch located from


automatic closing logic closed the breaker.The Wolf Creek licensee modified the EDG breaker control switch located in the control room to enable the operator to reclose the EDG circuit breaker from the control room. This switch was originally
control room to enable the operator to       reclose     the EDG circuit   breaker


intended only as a means of paralleling
of


the EDG with the offsite power supply. With the current modification, the switch can be used to reset the anti-pump
the control room. This switch was originally intended only as a means


logic and allow the automatic
paralleling the EDG with the offsite      power    supply.    With  the  current


circuit to re-close the breaker. The modification
allow


added a contact that is closed in the "normal" position and open in the "trip" and "pull to lock" positions
modification. the switch can be used to reset the anti-pump logic and


of the control switch.When operators
breaker.       The  modification      added  a


manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt
the automatic circuit to reclose the                                                     and


the close circuit and reset the circuit breaker anti-pump
contact that is closed in the "normal"      position    and   open  in  the   "trip"
                                                        switch.    When  operators    manually  trip


relay. If the operator wishes to keep the breaker open, he must put the switch in the "pull to lock" position.
"pull to lock" positions of the control                                            to


Returning
the EDG circuit breaker from this      control    switch.    the  contacts    open


the switch to the "normal" position completes
interrupt the close circuit and reset the circuit breaker anti-pump                relay.


the automatic
the breaker    open.  he  must  put  the  switch  in the


close circuit and the breaker recloses.It should be noted that although the above discussion
If the operator wishes to keep


has dealt only with EDG output circuit breakers, anti-pump
"pull to lock" position. Returning the switch to the "normal" position


circuit problems could also apply to other breakers that use automatic
completes the automatic close circuit and the breaker recloses.


closing logic, such as load-sequencing
EDG


breakers and offsite supply breakers to the emergency
It should be noted that although the above discussion has dealt only withto other


buses.The information
circuit    problem    could  also  apply


herein is being provided as an early notification
output circuit breakers. the anti-pump                                            breakers and


of a potentially
breakers that use automatic closing logic, such as load-sequencing


significant
offsite supply breakers to the emergency buses.


matter that is still under consideration
a


by the NRC staff. If NRC evaluation
The information herein is being provided as an early notification byof the NRC


so indicates, specific licensee actions may be requested.
potentially significant    matter that  is  still    under  consideration


No specific action or written response is required by this information
be


notice.If you have any questions
staff. If NRC evaluation so indicates. specific licensee actions may


about this matter, please contact one of the technical contacts listed below or the Regional Administrator
requested.


of the appropriate
No specific action or written response is required by this informationany of the


regional office.Charles E. Rossi, Director Division of Operational
notice. If you have any questions about this matter, please contact appropriate


===Events Assessment===
technical contacts listed below or the Regional Administrator of the
Office of Nuclear Reactor Regulation


Technical
regional office.


Contacts:
Charles E. Rossi, Director
James Lazevnick, NRR (301) 492-0814 Carl Schulten, NRR (301) 492-1192 Fred Burrows, NRR (301) 492-0783 Attachment:
List of Recently Issued NRC Information


Notices*SEE PREVIOUS PAGE FOR CONCURRENCE
Division of Operational Events Assessment


OFC *OEAB *Tech Ed *SL:OEAB *C:OEAB *D:DEST *C:OGCB NAME CSchulten
Office of Nuclear Reactor Regulation
 
BCalure PBaranowsky
 
WLanning LShao CBerlinger
 
e l DATE 9/7/88 7/28/88 9/7/88 9/7/88 8/24/88 9/8/88 9/(,f 88 IN 88-September , 1988 contact was reclosed by returning


the switch to the "auto" position.
Technical Contacts:  James Lazevnick. NRR


the circuit breaker's
(301) 492-0814 Carl Schulten. NRR


automatic
(301) 492-1192 Fred Burrows. NRR


closing logic closed the breaker.The Wolf Creek licensee modified the EDG breaker control switch located in the control room to enable the operator to reclose the EDG circuit breaker from the control room. This switch was originally
(301) 492-0783
                    -e            -                      ---
                                                          -      :D:                -
NAME :CSchu Mn          are      :P aranowsky :WLan n            :LShao            :CBeri nger      :ERossi


intended only as a means of paralleling
DATE  q    88                        /8        :1/88                    /88        :18188                /88 OFFICIAL RECORD COPY


the EDG with the offsite power supply. With the current modification.
IN 88- August . 1988 contact was reclosed by returning the switch to the "auto" position. the


the switch can be used to reset the anti-pump
circuit breaker's automatic closing logic closed the breaker.


logic and allow the automatic
the


circuit to reclose the breaker. The modification
The Wolf Creek licensee modified the EDG breaker control switch located in


added a contact that is closed in the "normal" position and open in the "trip" and"pull to lock" positions
breaker  from


of the control switch. When operators
control room to enable the operator to reclose the EDG circuit


manually trip the EDG circuit breaker from this control switch. the contacts open to interrupt
the control room. This switch was originally intended only as a means of


the close circuit and reset the circuit breaker anti-pump
paralleling the EDG with the offsite power supply. With the current


relay.If the operator wishes to keep the breaker open. he must put the switch in the"pull to lock" position.
modification. the switch can be used to reset the anti-pumping logic and allow


Returning
the automatic circuit to reclose the breaker. The modification added aand


the switch to the "normal" position completes
contact that is closed in the "normal" position and open in the "trip"          trip


the automatic
"pull to lock" positions of the control switch. When operators manually


close circuit and the breaker recloses.It should be noted that although the above discussion
the EDG circuit breaker from this control switch, the contacts      open  to


has dealt only with EDG output circuit breakers.
interrupt the close circuit and reset the circuit breaker anti-pumping relay.


the anti-pump
If the operator wishes to keep the breaker open. he must put the switch in the


circuit problem could also apply to other breakers that use automatic
"pull to lock" position. Returning the switch to the "normal" position


closing logic, such as load-sequencing
completes the automatic close circuit and the breaker recloses.


breakers and offsite supply breakers to the emergency
EDG


buses.The information
It should be noted that although the above discussion has dealt only with


herein is being provided as an early notification
output circuit breakers, the same problem could also apply      to  other  breakers


of a potentially
that use automatic closing logic, such as load-sequencing breakers and offsite


significant
supply breakers to the emergency buses.


matter that is still under consideration
The information herein is being provided as an early notification of a


by the NRC staff. If NRC evaluation
potentially significant matter that is still under consideration by the NRC


so indicates.
staff. If NRC evaluation so indicates. specific licensee actions may be


specific licensee actions may be requested.
requested.


No specific action or written response is required by this information
No specific action or written responses is required by this information             the


notice. If you have any questions
notice. If you have any questions about this matter, please contact either


about this matter, please contact any of the technical
technical contacts listed below or the Regional Administrator      of the appropriate


contacts listed below or the Regional Administrator
regional office.


of the appropriate
Charles E. Rossi. Director


regional office.Charles E. Rossi, Director Division of Operational
Division of Operational Events Assessment


===Events Assessment===
Office of Nuclear Reactor Regulation
Office of Nuclear Reactor Regulation


Technical
===Technical Contact:===
 
Contacts:  
James Lazevnick.
 
NRR (301) 492-0814 Carl Schulten.
 
NRR (301) 492-1192 Fred Burrows. NRR (301) 492-0783-e --- --:D: -NAME :CSchu Mn are :P aranowsky
 
:WLan n :LShao :CBeri nger :ERossi DATE q 88 /8 :1/88 /88 :18188 /88 OFFICIAL RECORD COPY
 
IN 88-August .1988 contact was reclosed by returning
 
the switch to the "auto" position.
 
the circuit breaker's
 
automatic
 
closing logic closed the breaker.The Wolf Creek licensee modified the EDG breaker control switch located in the control room to enable the operator to reclose the EDG circuit breaker from the control room. This switch was originally
 
intended only as a means of paralleling


the EDG with the offsite power supply. With the current modification.
===James Lazevnick. NRR===
                                (301) 492-0814 Carl Schulten. NRR


the switch can be used to reset the anti-pumping
(301) 492-1192 Fred Burrows. NRR


logic and allow the automatic
(301) 492-0783 T      EOGCB                                                          :D:DOEA


circuit to reclose the breaker. The modification
OFC  _:
                            t  -:-8{tjA---:-4og-yF---:---4-----------------:-----------
                                "4i>
                                                                                            :ERossi


added a contact that is closed in the "normal" position and open in the "trip" and"pull to lock" positions
NAME :CSchulten    :B& lure        :PB  pnowsky :WLanni:LS                :CBerlinger


of the control switch. When operators
:  //88        F./ A1/88        .1.V8 8    4f8                8/88COPY        8 DATE1&/O F:I                                  1                g/ECORD : /
DAT


manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt
OFFICIAL RECORD COPY


the close circuit and reset the circuit breaker anti-pumping
TO AUTOMATICALLY


relay.If the operator wishes to keep the breaker open. he must put the switch in the"pull to lock" position.
NRC INFO NOTICE 88-XX. DIESEL GENERATOR CIRCUIT BREAKERS FAIL


Returning
CLOSE


the switch to the "normal" position completes
:SL:OEAB    :C:OEAb    :L:SELB      :C:OGCB      :D:DUEA


the automatic
OFC  :OEAB        :Te h Ed


close circuit and the breaker recloses.It should be noted that although the above discussion
lure    :PBaranowsky :WLanning  :FRosa      :CBerlinger  :ERossl


has dealt only with EDG output circuit breakers, the same problem could also apply to other breakers that use automatic
closing logic, such as load-sequencing
breakers and offsite supply breakers to the emergency
buses.The information
herein is being provided as an early notification
of a potentially
significant
matter that is still under consideration
by the NRC staff. If NRC evaluation
so indicates.
specific licensee actions may be requested.
No specific action or written responses
is required by this information
notice. If you have any questions
about this matter, please contact either the technical
contacts listed below or the Regional Administrator
of the appropriate
regional office.Charles E. Rossi. Director Division of Operational
===Events Assessment===
Office of Nuclear Reactor Regulation
Technical
Contact: James Lazevnick.
NRR (301) 492-0814 Carl Schulten.
NRR (301) 492-1192 Fred Burrows. NRR (301) 492-0783 OFC _: T EOGCB :D:DOEA t "4i> -:-8{tjA---:-4og-yF---:---4-----------------
:-----------
NAME :CSchulten
NAME :CSchulten


:B& lure :PB pnowsky :WLanni:LS
/88   : I   /88       / /88   : /   /88   : /   /88 DATE :   / 88 OFFICIAL RECORD COPY}}
 
:CBerlinger
 
:ERossi DATE 1&/ : //88 F./ A1/88 1.V 1.8 8  4f8 8 8 DAT O F:I g/ECORD : / /88COPY OFFICIAL RECORD COPY
 
NRC INFO NOTICE 88-XX. DIESEL GENERATOR
 
===CIRCUIT BREAKERS FAIL TO AUTOMATICALLY===
CLOSE OFC :OEAB :Te h Ed :SL:OEAB :C:OEAb :L:SELB :C:OGCB :D:DUEA NAME :CSchulten
 
lure :PBaranowsky
 
:WLanning
 
:FRosa :CBerlinger
 
:ERossl DATE : / 88 /88 : I /88 / /88 : / /88 : / /88 OFFICIAL RECORD COPY}}


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

Latest revision as of 03:52, 24 November 2019

Disabling of Diesel Generator Output Circuit Breakers by Anti-Pump Circuitry
ML031150110
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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date: 09/16/1988
From: Rossi C
Office of Nuclear Reactor Regulation
To:
References
IN-88-075, NUDOCS 8809120197
Download: ML031150110 (8)
v • d • e


I

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 September 16, 1988 NRC INFORMATION NOTICE NO. 88-75: DISABLING OF DIESEL GENERATOR OUTPUT

CIRCUIT BREAKERS BY ANTI-PUMP CIRCUITRY

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is being provided to alert addressees to potential

problems where the capability to either automatically or manually close

diesel generator circuit breakers from the control room may be lost. 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 do not

constitute NRC requirements; therefore, no specific action or written response

is required.

Description of Circumstances

On June 5, 1988, operators at Browns Ferry Unit 3 were unable to reclose the

diesel generator output breakers to the 4-kV shutdown boards from the control

room during a loss-of-power/loss-of-coolant-accident (LOP/LOCA) test. During

the test, the output breakers connected the diesel generators to their respec- tive 4-kV shutdown boards after the LOP signal was generated; however, the

breakers tripped and remained open after receiving the LOCA signal. Operators

diagnosed the output breaker lockout problem using system electrical configu- ration drawings. An operator was sent to the 4-kY shutdown board to manually

transfer output breaker control power to its alternate source. This momentarily

removed power, enabling the breaker to close when the power was restored.

On October 14, 1987, an operator at Wolf Creek Generating Station manually

tripped the output circuit breaker of the emergency diesel generator (EDG)

from the control room. At the time, the EDG was supplying a vital bus. When

the operators tried to reenergize the vital bus from the still-operating EDG,

they found that they could not close the EDG output breaker from the control

room. The vital bus was finally reenergized from the offsite power supply.

Through examination of the breaker control schematics the licensee later

found that the EDG circuit breaker could be closed by cycling the EDG mode

switch at the EDG local control station.

880920197

IN 88-75 September 16, 1988 Discussion:

The anti-pump circuit configuration will protect large breakers from rapid

cycling and, under certain circumstances, will prevent breaker closure. At

Browns Ferry Unit 3, a unique sequence of events, a LOP signal followed within

6 seconds by a LOCA signal, led to the discovery of a design deficiency of this

circuit configuration. Contacts from the undervoltage relay will seal in the

breaker anti-pump relay until the undervoltage condition on the 4-kV boards

clears.

The circuit is designed such that following a LOP, the undervoltage condition

must exist for at least 5 seconds and the diesel. must reach rated speed before

the diesel generator output breaker will close on the bus. Once the breaker

has closed, the closure spring recharge motor and the breaker anti-pump relay

will be energized. A fully discharged closure spring requires 2 seconds for

the spring to be fully recharged. During this 2 second window the anti-pump

coil will remain energized via contacts sensing spring position, and if an

undervoltage condition exists on the 4-kY bus it will seal in and lock open

the breaker.

During the Browns Ferry event, the EDG output breaker closed 5 seconds after

the LOP signal, the undervoltage condition was eliminated, and the undervoltage

relay began its 5 second cycle to reset from the undervoltage condition. About

1.5 seconds 1ater. the.LOCA-signaL-retr-ipped-the-breaker-and-created-another--

undervoltage condition on the 4-kV bus. At this point, because the undervoltage

relay had not completed its reset cycle, the undervoltage relay remained in its

undervoltage state. Therefore, the undervoltage relay sealed in the still- energized anti-pump relay because the undervoltage condition occurred before

the breaker charging spring was fully charged. Thus, the breaker could not

be closed from the control room either manually or automatically until control

power was removed, which deenergized the anti-pump relay.

The Browns Ferry licensee modified the breaker control logic to prevent the anti- pump relay from sealing in during a LOCA condition by adding a time-delay relay

in the breaker trip coil circuitry. This relay will be energized by a LOCA

signal and its contact in the anti-pump coil seal-in path will open after a

2-to 5-second delay to prevent anti-pump coil seal-in and breaker lockout.

The Wolf Creek EDG output circuit breaker has automatic closing logic to close

the circuit breaker when the following five permissives are satisfied:

(1) Both offsite circuit breakers are open'

(2 The EDG mode switch is in the automatic mode.

(3 Lockout relays are deenergized.

(4 A 3-second time delay has elapsed.

(5) The EDG has reached operating speed and voltage.

This logic sends a constant close signal to the circuit breaker that keeps the

breaker's internal anti-pump relay energized as long as the logic permissives

are satisfied. The anti-pump relay prevents the circuit breaker from cycling

if attempts are made to hold the breaker closed against a valid trip signal.

I',

IN 88-75 September 16, 1988 When the Wolf Creek operator manually tripped the EDG output breaker, the auto- matic closing logic permissives remained satisfied. Therefore, the anti-pump

relay remained energized, preventing reclosure of the circuit breaker. Cycling

the EDG mode control switch at the local control station allowed the circuit

breaker to reclose by momentarily interrupting the automatic close signal, there- by resetting the anti-pump logic. When the mode switch contact was reclosed by

returning the switch to the "auto' position, the circuit breaker's automatic

closing logic closed the breaker.

The Wolf Creek licensee modified the EDG breaker control switch located in the

control room to enable the operator to reclose the EDG circuit breaker from the

control room. This switch was originally intended only as a means of paralleling

the EDG with the offsite power supply. With the current modification, the switch

can be used to reset the anti-pump logic and allow the automatic circuit to re- close the breaker. The modification added a contact that is closed in the "normal"

position and open in the "trip" and "pull to lock" positions of the control switch.

When operators manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt the close circuit and reset the circuit breaker

anti-pump relay. If the operator wishes to keep the breaker open, he must put

the switch in the "pull to lock" position. Returning the switch to the "normal"

position completes the automatic close circuit and the breaker recloses.

It should be noted that although the above discussion has dealt only with EDG

output- circuit breakers, anti-pump circuit problems could also apply to other

breakers that use automatic closing logic, such as load-sequencing breakers

and offsite supply breakers to the emergency buses.

The information herein is being provided as an early notification of a potentially

significant matter that is still under consideration by the NRC staff. If NRC

evaluation so indicates, specific licensee actions may be requested.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Di rector

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: James Lazevnick, NRR

(301) 492-0814 Carl Schulten, NRR

(301) 492-1192 Fred Burrows, NRR

(301) 492-0783 Attachment: List of Recently Issued NRC Information Notices

Att"aant

IN 88-75 September 16, 1988 Page I of I

LIST OF RECENTLY ISSUED

NRCINFORMATION NOTICES

Notice No. Subject Issuance Issued to

88-74 Potentially Inadequate 9/14/88 All holders of OLs

Perfornance of ECCSin or CPs for Wand

PWRs During Recirculation 8&W-designei nuclear

Operation Following a LOCA power reactors.

88-73 Direction-Dependent Leak 9/8/88 All holders of 0Ls

Characteristics of or CPs for nuclear

Containment Purge Valves power reactors.

88-72 Inadequacies in the Design 9/2/88 All holders of OLs

of dc Motor-Operated Valves or CPs for nuclear

power reactors.

88-71 Possible Environmental 9/1/88 All holders of OLs

Effect of the Reentry or CPs for nuclear

of COSMOS 1900 and power reactors, fuel

Request for Collection cycle licensees, of Licensee Radioactivity and Priority I

Measurements Attributed material licensees.

to That Event

88-70 Check Valve Inservice 8/29/88 All holders of OLs

Testing Program or CPs for nuclear

Deficiencies power reactors.

88-69 Movable Contact Finger 8/19/88 All holders of OLs

Binding in HFA Relays or CPs for nuclear

Manufactured by General power reactors.

Electric (GE)

88-48, Licensee Report of Defective 8/24/88 All holders of OLs

Supplement I Refurbished Valves or CPs for nuclear

power reactors.

88-68 Setpoint Testing of Pres- 8/22/88 All holders of OLs

surizer Safety Valves with or CPs for nuclear

Filled Loop Seals Using power reactors.

Hydraulic Assist Devices

_

88P67- -P-F Zfiiairy Fiedeaer Pump 8/Z2j88 All holders of OLs

Turbine Overspeed Trip or CPs for nuclear

Failure power reactors.

OL

  • Operating License

CP* Construction Permit

UNITED STATES FIRST CLASS MAIL

NUCLEAR REGULATORY COMMISSION POSTAGE & FEES PAID

USNRC

WASHINGTON, D.C. 20555 PERMIT No. 0-57 OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

IN 88-75 September 16, 1988 When the Wolf Creek operator manually tripped the EDG output breaker, the auto- matic closing logic permissives remained satisfied. Therefore, the anti-pump

relay remained energized, preventing reclosure of the circuit breaker. Cycling

the EDG mode control switch at the local control station allowed the circuit

breaker to reclose by momentarily interrupting the automatic close signal, there- by resetting the anti-pump logic. When the mode switch contact was reclosed by

returning the switch to the "auto" position, the circuit breaker's automatic

closing logic closed the breaker.

The Wolf Creek licensee modified the EDG breaker control switch located in the

control room to enable the operator to reclose the EDG circuit breaker from the

control room. This switch was originally intended only as a means of paralleling

the EDG with the offsite power supply. With the current modification, the switch

can be used to reset the anti-pump logic and allow the automatic circuit to re- close the breaker. The modification added a contact that is closed in the "normal"

position and open in the "trip" and "pull to lock" positions of the control switch.

When operators manually trip the EDG circuit breaker from this control switch, the contacts open to interrupt the close circuit and reset the circuit breaker

anti-pump relay. If the operator wishes to keep the breaker open, he must put

the switch in the "pull to lock" position. Returning the switch to the "normal"

position completes the automatic close circuit and the breaker recloses.

It should be noted that although the above discussion has dealt only with EDG

output circuit breakers, anti-pump circuit problems could also apply to other

breakers that use automatic closing logic, such as load-sequencing breakers

and offsite supply breakers to the emergency buses.

The information herein is being provided as an early notification of a potentially

significant matter that is still under consideration by the NRC staff. If NRC

evaluation so indicates, specific licensee actions may be requested.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the technical

contacts listed below or the Regional Administrator of the appropriate regional

office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: James Lazevnick, NRR

(301) 492-0814 Carl Schulten, NRR

(301) 492-1192 Fred Burrows, NRR

(301) 492-0783 Attachment: List of Recently Issued NRC Information Notices

  • SEE PREVIOUS PAGE FOR CONCURRENCE

OFC *OEAB Ed *SL:OEAB

  • Tech *C:OEAB *D:DEST *C:OGCB

NAME CSchulten BCalure PBaranowsky WLanning LShao CBerlinger e l

9/(,f 88 DATE 9/7/88 7/28/88 9/7/88 9/7/88 8/24/88 9/8/88

IN 88- September , 1988 the

contact was reclosed by returning the switch to the "auto" position.

circuit breaker's automatic closing logic closed the breaker.

in the

The Wolf Creek licensee modified the EDG breaker control switch located from

control room to enable the operator to reclose the EDG circuit breaker

of

the control room. This switch was originally intended only as a means

paralleling the EDG with the offsite power supply. With the current

allow

modification. the switch can be used to reset the anti-pump logic and

breaker. The modification added a

the automatic circuit to reclose the and

contact that is closed in the "normal" position and open in the "trip"

switch. When operators manually trip

"pull to lock" positions of the control to

the EDG circuit breaker from this control switch. the contacts open

interrupt the close circuit and reset the circuit breaker anti-pump relay.

the breaker open. he must put the switch in the

If the operator wishes to keep

"pull to lock" position. Returning the switch to the "normal" position

completes the automatic close circuit and the breaker recloses.

EDG

It should be noted that although the above discussion has dealt only withto other

circuit problem could also apply

output circuit breakers. the anti-pump breakers and

breakers that use automatic closing logic, such as load-sequencing

offsite supply breakers to the emergency buses.

a

The information herein is being provided as an early notification byof the NRC

potentially significant matter that is still under consideration

be

staff. If NRC evaluation so indicates. specific licensee actions may

requested.

No specific action or written response is required by this informationany of the

notice. If you have any questions about this matter, please contact appropriate

technical contacts listed below or the Regional Administrator of the

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: James Lazevnick. NRR

(301) 492-0814 Carl Schulten. NRR

(301) 492-1192 Fred Burrows. NRR

(301) 492-0783

-e - ---

- :D: -

NAME :CSchu Mn are :P aranowsky :WLan n :LShao :CBeri nger :ERossi

DATE q 88 /8 :1/88 /88 :18188 /88 OFFICIAL RECORD COPY

IN 88- August . 1988 contact was reclosed by returning the switch to the "auto" position. the

circuit breaker's automatic closing logic closed the breaker.

the

The Wolf Creek licensee modified the EDG breaker control switch located in

breaker from

control room to enable the operator to reclose the EDG circuit

the control room. This switch was originally intended only as a means of

paralleling the EDG with the offsite power supply. With the current

modification. the switch can be used to reset the anti-pumping logic and allow

the automatic circuit to reclose the breaker. The modification added aand

contact that is closed in the "normal" position and open in the "trip" trip

"pull to lock" positions of the control switch. When operators manually

the EDG circuit breaker from this control switch, the contacts open to

interrupt the close circuit and reset the circuit breaker anti-pumping relay.

If the operator wishes to keep the breaker open. he must put the switch in the

"pull to lock" position. Returning the switch to the "normal" position

completes the automatic close circuit and the breaker recloses.

EDG

It should be noted that although the above discussion has dealt only with

output circuit breakers, the same problem could also apply to other breakers

that use automatic closing logic, such as load-sequencing breakers and offsite

supply breakers to the emergency buses.

The information herein is being provided as an early notification of a

potentially significant matter that is still under consideration by the NRC

staff. If NRC evaluation so indicates. specific licensee actions may be

requested.

No specific action or written responses is required by this information the

notice. If you have any questions about this matter, please contact either

technical contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi. Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

James Lazevnick. NRR

(301) 492-0814 Carl Schulten. NRR

(301) 492-1192 Fred Burrows. NRR

(301) 492-0783 T EOGCB :D:DOEA

OFC _:

t -:-8{tjA---:-4og-yF---:---4-----------------:-----------

"4i>

ERossi

NAME :CSchulten :B& lure :PB pnowsky :WLanni:LS :CBerlinger

//88 F./ A1/88 .1.V8 8 4f8 8/88COPY 8 DATE1&/O F:I 1 g/ECORD : /

DAT

OFFICIAL RECORD COPY

TO AUTOMATICALLY

NRC INFO NOTICE 88-XX. DIESEL GENERATOR CIRCUIT BREAKERS FAIL

CLOSE

SL:OEAB :C:OEAb :L:SELB :C:OGCB :D:DUEA

OFC :OEAB :Te h Ed

lure :PBaranowsky :WLanning :FRosa :CBerlinger :ERossl

NAME :CSchulten

/88  : I /88 / /88  : / /88  : / /88 DATE : / 88 OFFICIAL RECORD COPY


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