Information Notice 1991-29, Deficiencies Identifie During Electrical Distribution System Functional Inspections: Difference between revisions

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{{#Wiki_filter:4 A UNITED STATES NUCLEAR REGULATORY
{{#Wiki_filter:4 A


COMMISSION
UNITED STATES


===OFFICE OF NUCLEAR REACTOR REGULATION===
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555 April 15, 1991 NRC INFORMATION


NOTICE NO. 91-29: DEFICIENCIES
OFFICE OF NUCLEAR REACTOR REGULATION


IDENTIFIED
WASHINGTON, D.C. 20555 April 15, 1991 NRC INFORMATION NOTICE NO. 91-29:  DEFICIENCIES IDENTIFIED DURING ELECTRICAL


===DURING ELECTRICAL===
DISTRIBUTION SYSTEM FUNCTIONAL INSPECTIONS
DISTRIBUTION
 
SYSTEM FUNCTIONAL
 
INSPECTIONS


==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 intended to alert addressees to deficiencies identi- fied during recently performed electrical distribution system functional


notice is intended to alert addressees
inspections (EDSFIs). It is expected that recipients will review the informa- tion for applicability to their facilities and consider actions, as appropri- ate, to avoid similar problems. However, suggestions contained in this


to deficiencies
information notice do not constitute NRC requirements; therefore, no specific


identi-fied during recently performed
action or written response is required.


electrical
==Description of Circumstances==
 
:
distribution
  During multidisciplinary inspections, the U.S. Nuclear Regulatory Commission
 
system functional
 
inspections (EDSFIs).
 
It is expected that recipients
 
will review the informa-tion for applicability
 
to their facilities
 
and consider actions, as appropri-ate, 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:
During multidisciplinary
 
inspections, the U.S. Nuclear Regulatory
 
Commission (NRC) has identified
 
many deficiencies
 
related to tWeelectrical
 
distribution
 
system. To address these deficiencies, the NRC has developed
 
an inspection
 
to specifically
 
evaluate the electrical
 
distribution
 
system. During the last year, the NRC completed
 
eight EDSFIs, performing
 
at least one in each of the five NRC geographical
 
regions. During these inspections, the staff found several common deficiencies
 
in the licensees'
programs and in the electrical
 
distribution


systems as designed and configured
(NRC) has identified many deficiencies related to tWeelectrical distribution


at each plant. These deficien-cies included inadequate
system. To address these deficiencies, the NRC has developed an inspection to


ac voltages at the 480 Vac and 120 Vac distribution
specifically evaluate the electrical distribution system. During the last


levels, inadequate
year, the NRC completed eight EDSFIs, performing at least one in each of the


procedures
five NRC geographical regions. During these inspections, the staff found


to test circuit breakers, and inadequate
several common deficiencies in the licensees' programs and in the electrical


determi-nations and evaluations
distribution systems as designed and configured at each plant. These deficien- cies included inadequate ac voltages at the 480 Vac and 120 Vac distribution


of setpoints.
levels, inadequate procedures to test circuit breakers, and inadequate determi- nations and evaluations of setpoints.


Discussion:
Discussion:
Inadequate
  Inadequate Voltage
 
Voltage During inspections
 
conducted
 
at the San Onofre Nuclear Generating
 
Station (Inspection
 
Reports 50-361/89-200
and 50-362/89-200), the Susquehanna
 
Steam Electric Station (Inspection
 
Reports 50-387/90-200
and 50-388/90-200), and the 9104090124
' J IN 91-29 April 15, 1991 Waterford
 
Steam Electric Station (Inspection
 
Report 50-382/90-23), the staff found that, under certain conditions, the voltage available
 
at the safety buses would be inadequate
 
to Operate safety-related
 
loads and associated
 
equipment.
 
These conditions
 
could occur when the plan~t's electrical
 
distribution
 
systems were being supplied from an offsite grid that had become degraded but that continued
 
to supply voltages that remained above the setpoints
 
at which the degraded grid relays would be activated.


At San Onofre, the numerous voltage drops throughout
During inspections conducted at the San Onofre Nuclear Generating Station


the system could cause the voltage to 120 Vaciontactors
(Inspection Reports 50-361/89-200 and 50-362/89-200), the Susquehanna Steam


to drop below the-voltage
Electric Station (Inspection Reports 50-387/90-200 and 50-388/90-200), and the


range for which these contactors
9104090124


were certified
'J


as acceptable
IN 91-29 April 15, 1991 Waterford Steam Electric Station (Inspection Report 50-382/90-23), the staff


by their manufacturers.
found that, under certain conditions, the voltage available at the safety buses


To resolve this problem the licensee has performed
would be inadequate to Operate safety-related loads and associated equipment.


testing that established
These conditions could occur when the plan~t's electrical distribution systems


a lower acceptable
were being supplied from an offsite grid that had become degraded but that


voltage range for this equipment.
continued to supply voltages that remained above the setpoints at which the


At Susquehanna, the degraded grid relay setpoint'was'set
degraded grid relays would be activated.


at 84 percent on the 4160 Yac buses. Th'i's setpoint could have allowed inadequate
At San Onofre, the numerous voltage drops throughout the system could cause the


voltage to be-delivered
voltage to 120 Vaciontactors to drop below the-voltage range for which these


to numerous safety-related
contactors were certified as acceptable by their manufacturers. To resolve


loads at both the 480 Vac and 120 Vac levels. The licensee calculated
this problem the licensee has performed testing that established a lower


that setpoints'of
acceptable voltage range for this equipment.


at least 93 percent would be required to ensure adequate voTtage to all safety-related
At Susquehanna, the degraded grid relay setpoint'was'set at 84 percent on the


equipment.
4160 Yac buses. Th'i's setpoint could have allowed inadequate voltage to be


To resolve this problem, the lice'isee
-delivered to numerous safety-related loads at both the 480 Vac and 120 Vac


has raised the setpoints
levels. The licensee calculated that setpoints'of at least 93 percent would be


of the degraded grid relays and has initiated
required to ensure adequate voTtage to all safety-related equipment. To


a modification
resolve this problem, the lice'isee has raised the setpoints of the degraded


to install 120 Vac regulating
grid relays and has initiated a modification to install 120 Vac regulating


transformers.
transformers.


At the Waterford
At the Waterford nuclear plant, the degraded grid relays were set at
 
nuclear plant, the degraded grid relays were set at 87.5 percent'as
 
sensed on the'4160 Vac buses. :Although
 
this setting was found to be marginally
 
adequate-'for-equipment
 
connected
 
to the 4160 Vac buses, the setting was too low to ensure that adequate v6ltage would'be maintained
 
at the 480 Vac and 120 Vac levels. The licensee is 6e4aluating
 
solutions
 
to this problem and has instituted
 
a procedure- to manually'separate
 
from the grid if the voltage falls to unacceptable
 
levels but remains above the relay setpoints.
 
The function of the degraded grid relays is to en'sure that adequate voltage is available
 
tooperate
 
all Class lE loads at all distribution
 
levels. In order to ensure-that
 
all required'
Class E 'loads will remain operable during degraded voltage conditions, some licensees
 
are currently'reanalyzing
 
the basis for the degraded grid relay setpoints.
 
The new analyses consider all required Class 1E loads and include the assumption
 
that the voltage on the buses being sensed by these relays can remain at a level just above the relay setpoints.
 
Inadequate
 
===Circuit Breaker Testing Procedures===
During recent EDSFIs ahd previously
 
on other NRC inspections, the staff identi-fied repetitive
 
deficiencies
 
in licensees'
programs to test circuit breakers.These deficiencies
 
included inadequate
 
procedures, inadequate
 
test acceptance
 
criteria, inadequate
 
test equipment, and inadequate
 
control of testing. At the Susquehanna
 
plant (Inspection
 
Reports 50-387/90-200
and 50-388/90-200), the staff found that the licensee was testing dc molded case circuit breakers with a procedure
 
written for testing ac breakers.
 
===The licensee had not established===
specific acceptance
 
criteria for the dc breakers.
 
IN 91-29 April 15, 1991 At the Shearon Harris Nuclear Power Plant (Inspection
 
Report 50-400/90-200), the staff identified
 
that the licensee was.testing
 
molded case circuit breakers against National Electrical
 
Manufacturers
 
Association (NEMA),acceptance
 
crite-ria, which were less stringent
 
than the manufacturer's
 
time-current
 
curves for these breakers.
 
In addition, the staff identified
 
that the licensee was testing 480 V air circuit breakers with test equipment
 
that applied a test signal (secondary
 
injection)
to the solid state trip units in the circuit breakers.
 
Although this method adequately
 
verified that the trip units func-tioned properly, it did not verify that the breaker's
 
current transformer
 
functioned
 
properly or that the wiring and connectors
 
were adequate between the current transformer
 
and the solid state trip units. Other licensees
 
have performed
 
testing by primary current injection
 
or by individually
 
checking each component
 
of the circuit breaker, including
 
the wiring and connectors
 
to demonstrate
 
that the circuit breaker functions
 
properly.Inadequate
 
Determinations
 
and Evaluations
 
of Setpoints Many of the findings identified
 
during recent EDSFIs were related to inadequate
 
setpoint determinations.
 
Useful guidance for determining
 
setpoints
 
is provided by Instrument
 
Society of America Standard 67.04-1982, "Setpoints
 
for Nuclear Safety-Related
 
Instrumentation
 
used in Nuclear Power Plants," which the NRC staff has endorsed by Regulatory
 
Guide 1.105 Revision 2 -1986, "Instrument
 
Setpoints
 
for Safety-Related
 
Systems." This guidance applies both to process instrumentation


and, in part, to certain relays that perform a safety function.Some licensees
87.5 percent'as sensed on the'4160 Vac buses. :Although this setting was found


have operated equipment
to be marginally adequate-'for-equipment connected to the 4160 Vac buses, the


outside of acceptable
setting was too low to ensure that adequate v6ltage would'be maintained at the


limits because they did not determine
480 Vac and 120 Vac levels. The licensee is 6e4aluating solutions to this


proper setpoints
problem and has instituted a procedure- to manually'separate from the grid if


and did not evaluate and account for instrument
the voltage falls to unacceptable levels but remains above the relay setpoints.


drift. Operating
The function of the degraded grid relays is to en'sure that adequate voltage is


the equipment
available tooperate all Class lE loads at all distribution levels. In order


under these conditions
to ensure-that all required'Class E 'loads will remain operable during degraded


could compromise
voltage conditions, some licensees are currently'reanalyzing the basis for the


the safety functions
degraded grid relay setpoints. The new analyses consider all required Class 1E


of the equipment.
loads and include the assumption that the voltage on the buses being sensed by


===The staff has identified===
these relays can remain at a level just above the relay setpoints.
these circumstances


primarily
===Inadequate Circuit Breaker Testing Procedures===
During recent EDSFIs ahd previously on other NRC inspections, the staff identi- fied repetitive deficiencies in licensees' programs to test circuit breakers.


for those instruments
These deficiencies included inadequate procedures, inadequate test acceptance


in which the licensee has determined
criteria, inadequate test equipment, and inadequate control of testing. At the


the setpoints
Susquehanna plant (Inspection Reports 50-387/90-200 and 50-388/90-200), the


as opposed to those instruments
staff found that the licensee was testing dc molded case circuit breakers with


for which the setpoints
a procedure written for testing ac breakers. The licensee had not established


were determined
specific acceptance criteria for the dc breakers.


by the architect/engineer
IN 91-29 April 15, 1991 At the Shearon Harris Nuclear Power Plant (Inspection Report 50-400/90-200),
the staff identified that the licensee was.testing molded case circuit breakers


or the nuclear safety system supplier.
against National Electrical Manufacturers Association (NEMA),acceptance crite- ria, which were less stringent than the manufacturer's time-current curves for


Those setpoints
these breakers. In addition, the staff identified that the licensee was


not contained
testing 480 V air circuit breakers with test equipment that applied a test


in the plant technical
signal (secondary injection) to the solid state trip units in the circuit


specifi-cations were also more frequently
breakers. Although this method adequately verified that the trip units func- tioned properly, it did not verify that the breaker's current transformer


found to be deficient.
functioned properly or that the wiring and connectors were adequate between the


During recent EDSFIs, the staff identified
current transformer and the solid state trip units. Other licensees have


deficiencies
performed testing by primary current injection or by individually checking each


in setpoints
component of the circuit breaker, including the wiring and connectors to


for diesel day tank level indicators, diesel air start compressor
demonstrate that the circuit breaker functions properly.


controllers
Inadequate Determinations and Evaluations of Setpoints


and alarms, inverter low voltage shutdown circuitry, degraded grid relays, and diesel overcurrent
Many of the findings identified during recent EDSFIs were related to inadequate


relays.In addition to identifying
setpoint determinations. Useful guidance for determining setpoints is provided


deficiencies
by Instrument Society of America Standard 67.04-1982, "Setpoints for Nuclear


in the setpoints
Safety-Related Instrumentation used in Nuclear Power Plants," which the NRC


themselves, the NRC has determined
staff has endorsed by Regulatory Guide 1.105 Revision 2 - 1986, "Instrument


that not all the licensees
Setpoints for Safety-Related Systems." This guidance applies both to process


are typically
instrumentation and, in part, to certain relays that perform a safety function.


verifying
Some licensees have operated equipment outside of acceptable limits because


that the magnitude
they did not determine proper setpoints and did not evaluate and account for


of instrument
instrument drift. Operating the equipment under these conditions could


drift that was assumed in the original setpoint calcu-lation coincides
compromise the safety functions of the equipment. The staff has identified


with the magnitude
these circumstances primarily for those instruments in which the licensee has


of drift observed in the plant. Some licensees
determined the setpoints as opposed to those instruments for which the


have corrected
setpoints were determined by the architect/engineer or the nuclear safety


this deficiency
system supplier. Those setpoints not contained in the plant technical specifi- cations were also more frequently found to be deficient. During recent EDSFIs, the staff identified deficiencies in setpoints for diesel day tank level


by verifying
indicators, diesel air start compressor controllers and alarms, inverter low


the magnitude
voltage shutdown circuitry, degraded grid relays, and diesel overcurrent


of instru-ment drift by trending, (comparing "as found" calibration
relays.


data to previous "as left" data). This is particularly
In addition to identifying deficiencies in the setpoints themselves, the NRC


important
has determined that not all the licensees are typically verifying that the


for the degraded grid relay setpoints, which often require very tight calibration
magnitude of instrument drift that was assumed in the original setpoint calcu- lation coincides with the magnitude of drift observed in the plant. Some


tolerance
licensees have corrected this deficiency by verifying the magnitude of instru- ment drift by trending, (comparing "as found" calibration data to previous "as


bands, and for which very low drift values are often assumed.
left" data). This is particularly important for the degraded grid relay


v-IN 91-29 April 15, 1991 This information
setpoints, which often require very tight calibration tolerance bands, and for


notice requires no specific action or written response.
which very low drift values are often assumed.


If you have any questions
v- IN 91-29 April 15, 1991 This information notice requires no specific action or written response. If


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


in this notice, please contact the technical
technical contact listed below or the appropriate NRR project manager.


contact listed below or the appropriate
Charles E. Rossi, eirector


NRR project manager.Charles E. Rossi, eirector Division of Operational
Division of Operational Events Assessment


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


Technical
===Technical Contact:===
 
Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 Attachment:
List of Recently Issued NRC Information
 
Notices i


Attachment
===Jeffrey B. Jacobson, NRR===
                    (301) 492-0996 Attachment:  List of Recently Issued NRC Information Notices


1 IN 91-29 April 15, 1991 LIST OF RECENTLY ISSUED NRC INFORMATION
i


NOTICES Information
Attachment 1 IN 91-29 April 15, 1991 LIST OF RECENTLY ISSUED


Date of Notice No. Subject Issuance Issued to 91-28 91-27 89-90, Supp. 1 91-26 91-25 91-24 91-23 Cracking in Feedwater System Piping Incorrect
NRC INFORMATION NOTICES


Rotation of Positive Displacement
Information                                        Date of


Pump Pressurizer
Notice No.              Subject                    Issuance  Issued to


Safety Valve Lift Setpoint Shift Potential
91-28          Cracking in Feedwater              04/15/91  All holders of OLs or


===Nonconservative===
System Piping                                CPs for pressurized
Errors in the Working Format Hansen-Roach


Cross-Section
water reactors (PWRs).


Set Provided with The Keno and Scale Codes Commercial-Grade
91-27          Incorrect Rotation of              04/10/91  All holders of OLs or


Structural
Positive Displacement Pump                    CPs for nuclear power


Framing Components
reactors.


Supplied As Nuclear Safety-Related
89-90,          Pressurizer Safety Valve            04/10/91  All holders of OLs or


Equipment Recent Operating
Supp. 1        Lift Setpoint Shift                          CPs for nuclear power


Experience
reactors.


Involving
91-26          Potential Nonconservative          04/02/91  All fuel cycle licensees


Reactor Operation Without A Licensed Reactor Operator or Senior Reactor Operator Present in the Control Room Accidental
Errors in the Working Format                  and other licensees, in- Hansen-Roach Cross-Section                    cluding all holders of


Radiation
Set Provided with The Keno                    operating licenses for


Over-exposures
and Scale Codes                              nuclear power reactors, who use physics codes to


to Personnel
support criticality


Due to Industrial
safety in the use of


Radiography
fissile material.


Acces-sory Equipment
91-25          Commercial-Grade Structural          04/01/91  All holders of OLs or


===Malfunctions===
Framing Components Supplied                    CPs for nuclear power
04/15/91 All holders of OLs or CPs for pressurized


water reactors (PWRs).04/10/91 All holders of OLs or CPs for nuclear power reactors.04/10/91 All holders of OLs or CPs for nuclear power reactors.04/02/91 All fuel cycle licensees and other licensees, in-cluding all holders of operating
As Nuclear Safety-Related                      reactors.


licenses for nuclear power reactors, who use physics codes to support criticality
Equipment


safety in the use of fissile material.04/01/91 All holders of OLs or CPs for nuclear power reactors.03/26/91 All holders of OLs or CPs for nuclear power, test, and research re-actors, and all Part 55 licensed operators.
91-24          Recent Operating Experience          03/26/91 All holders of OLs or


03/26/91 All Nuclear Regulatory
Involving Reactor Operation                  CPs for nuclear power, Without A Licensed Reactor                    test, and research re- Operator or Senior Reactor                    actors, and all Part 55 Operator Present in the                        licensed operators.


Commission (NRC) licens-ees authorized
Control Room


to use sealed sources for indus-trial radiography.
91-23          Accidental Radiation Over-          03/26/91  All Nuclear Regulatory


OL = Operating
exposures to Personnel Due to                Commission (NRC) licens- Industrial Radiography Acces-                ees authorized to use


License CP = Construction
sory Equipment Malfunctions                  sealed sources for indus- trial radiography.


Permit
OL = Operating License


IN 91-29 April 15, 1991 This information
CP = Construction Permit


notice requires no specific action or written response.
IN 91-29 April 15, 1991 This information notice requires no specific action or written response. If


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


about the information
technical contact listed below or the appropriate NRR project manager.


in this notice, please contact the technical
O6ginal agen& by


contact listed below or the appropriate
Charles E. Ross!
                                    Charles E. Rossi, Director


NRR project manager.O6ginal agen& by Charles E. Ross!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:===


Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 Attachment:
===Jeffrey B. Jacobson, NRR===
List of Recently Issued NRC Information
                      (301) 492-0996 Attachment: List of Recently Issued NRC Information Notices


Notices*SEE PREVIOUS 04/ fI9 OGC :DOEA: RR PCWen 04/ /91 CONCURRENCES
*SEE PREVIOUS CONCURRENCES
 
*C/OGCB:DOEA:NRR*RPB:ADM
 
*C/SICB:DST:NRR


CHBerlinger
*C/OGCB:DOEA:NRR*RPB:ADM              *C/SICB:DST:NRR *C/SELB:DST:NRR


TechEd SNewberry 04/08/91 03/20/91 03/18/91*RSIB:DRIS:NRR
CHBerlinger      TechEd               SNewberry       FRosa


*SC/RSIB:DRIS:NRR*C/RSIB:DRIS:NRR
04/ fI9        04/08/91        03/20/91            03/18/91        03/18/91 OGC :DOEA: RR *RSIB:DRIS:NRR *SC/RSIB:DRIS:NRR*C/RSIB:DRIS:NRR      *D/DRIS:NRR


JBJacobson:bt
PCWen          JBJacobson:bt   EVImbro              WDLanning        BKGrimes


EVImbro WDLanning 02/08/91 02/08/91 02/19/91*C/SELB:DST:NRR
04/ /91        02/08/91         02/08/91             02/19/91       02/27/91


FRosa 03/18/91*D/DRIS:NRR
*- I                    IN 91-XX


BKGrimes 02/27/91
April xx, 1991 If
*- I IN 91-XX April xx, 1991 This information


notice requires no specific action or written response.
no specific action or written response.


If you have any questions
This information notice requires information in this notice, please contact the


about the information
you have any questions about the the appropriate NRR project manager.


in this notice, please contact the technical
technical contact listed below or


contact listed below or the appropriate
Charles E. Rossi, Director


NRR project manager.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:===
 
Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 List of Recently Issued NRC Information
 
Notices Attachment:
*SEE PREVIOUS CONCURRENCES
 
*C/SICB:DST:NRR
 
D/DOEA:NRR
 
C/OGCB:DO
 
T*RPB:Ad SNewBerry CERossi Y- CHBerling
 
rjw TechEd 04/ /91 04/8/91 03/20/91 03/18/91 ,c CB:DOEA:NRR
 
*RSIB:DRIS:NRR
 
*SC/RSIB:DRIS:NRR*C/RSIB:DRISNRR
 
4CvPvWen JBJacobson:bt
 
EVImbro WMLanning 04/cl/91 02/08/91 02/08/91 02/19/91*C/SELB:DST:NRR
 
FRosa 03/18/91*D/DRIS:NRR
 
BKGrimes 02/27/91 IN 91-XX March xx, 1991 Inadequate
 
Determinations
 
and Evaluations
 
of Setpoints Many of the findings identified
 
during recent EDSFIs related to inadequate
 
setpoint determinations.
 
Useful guidance for determining
 
setpoints
 
is provided by Instrument
 
Society of America Standard 67.04-1982, "Setpoints
 
for Nuclear Safety-Related
 
Instrumentation
 
used in Nuclear Power Plants," which the NRC staff has endorsed by Regulatory
 
Guide 1.105 Revision 2 -1986, "Instrument
 
Setpoints
 
for Safety-Related
 
Systems." This guidance applies both to process instrumentation
 
and, in part, to certain relays that perform a safety function.Licensees
 
have operated equipment
 
outside of acceptable
 
limits because they did not determine
 
proper setpoints
 
and did not evaluate and account for instrument
 
drifts. Operating
 
the equipment
 
under these conditions
 
could compromise
 
the safety functions
 
of the equipment.
 
The staff has identified
 
these circum-stances primarily


for those instruments
===Jeffrey B. Jacobson, NRR===
                      (301) 492-0996 Notices


in which the licensee has determined
Attachment:    List of Recently Issued NRC Information


the setpoints
*SEE PREVIOUS CONCURRENCES                      *C/SICB:DST:NRR *C/SELB:DST:NRR


as opposed to those instruments
T*RPB:Ad            SNewBerry        FRosa


for which the setpoints
D/DOEA:NRR      C/OGCB:DO


were determined
CERossi  Y-    CHBerling rjw  TechEd                            03/18/91
                                    03/20/91          03/18/91
  04/ /91          04/8/91                                          *D/DRIS:NRR


by the architect/engineer
,cCB:DOEA:NRR *RSIB:DRIS:NRR *SC/RSIB:DRIS:NRR*C/RSIB:DRISNRR


or the nuclear safety system supplier.Those setpoints
WMLanning        BKGrimes


not contained
JBJacobson:bt  EVImbro                            02/27/91
  4CvPvWen                          02/08/91          02/19/91
    04/cl/91        02/08/91


in the plant technical
IN 91-XX


specifications
March xx, 1991 Inadequate Determinations and Evaluations of Setpoints


were also more frequently
Many of the findings identified during recent EDSFIs related to inadequate


found to be deficient.
setpoint determinations. Useful guidance for determining setpoints is provided


During recent EDSFIs, the staff identified
by Instrument Society of America Standard 67.04-1982, "Setpoints for Nuclear


deficiencies
Safety-Related Instrumentation used in Nuclear Power Plants," which the NRC


in setpoints
staff has endorsed by Regulatory Guide 1.105 Revision 2 - 1986, "Instrument


for diesel day tank level indicators, diesel air start compressor
Setpoints for Safety-Related Systems." This guidance applies both to process


controllers
instrumentation and, in part, to certain relays that perform a safety function.


and alarms, inverter low voltage shutdown circuitry, degraded grid relays, and diesel overcurrent
did


relays.In addition to identifying
Licensees have operated equipment outside of acceptable limits because they


deficiencies
not determine proper setpoints and did not evaluate and account for instrument


in the setpoints
drifts. Operating the equipment under these conditions could compromise the


themselves, the NRC has determined
safety functions of the equipment. The staff has identified these circum- stances primarily for those instruments in which the licensee has determined


that licensees
the setpoints as opposed to those instruments for which the setpoints were


are not typically
determined by the architect/engineer or the nuclear safety system supplier.


verifying
Those setpoints not contained in the plant technical specifications were also


that the magnitude of instrument
more frequently found to be deficient. During recent EDSFIs, the staff


drift that was assumed in the original setpoint calculation
identified deficiencies in setpoints for diesel day tank level indicators, diesel air start compressor controllers and alarms, inverter low voltage


coincides
shutdown circuitry, degraded grid relays, and diesel overcurrent relays.


with the magnitude
NRC


of drift observed in the plant. Licensee can verify the magnitude
In addition to identifying deficiencies in the setpoints themselves, the


of instrument
has determined that licensees are not typically verifying that the        magnitude


drift by trending, (comparing
of instrument drift that was assumed in the original setpoint calculation


'as found" calibration
coincides with the magnitude of drift observed in the plant. Licenseefound"   can


data to previous 'as left" data). This is particularly
verify the magnitude of instrument drift by trending, (comparing 'as


important for the degraded grid relay setpoints, which often require very tight calibra-tion tolerance
calibration data to previous 'as left" data). This is particularly important


bands, and for which very low drift values are often assumed.This information
for the degraded grid relay setpoints, which often require very tight calibra- tion tolerance bands, and for which very low drift values are often assumed.


notice requires no specific action or written response.
If


If you have any questions
This information notice requires no specific action or written response.  contact  the


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


in this notice, please contact the technical
technical contact listed below or the appropriate NRR project      manager.


contact listed below or the appropriate
Charles E. Rossi, Director


NRR project manager.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:===
 
Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 Attachment:
RPB:ADM TechEd* imJa 03/20/91 P RSIB:DRIS JBdacobson*:t
 
02/08/91 List of Recently Issued NRC Information
 
Notices C:OGCB:UOEA
 
D:DOEA *See previous c CHBerlinger
 
CERossi 1 03/l/91 03/ /91 oncurrence


bt SC:RSIB:DRIS
===Jeffrey B. Jacobson, NRR===
                          (301) 492-0996 Attachment:     List of Recently Issued NRC Information Notices


EVImbro*02/08/91 C:RSIB:DRIS
RPB:ADM            C:OGCB:UOEA    D:DOEA        *See previous concurrence


WDLanning*
TechEd* i m Ja    CHBerlinger    CERossi
02/19/91 D:DRIS BKGrimes*02/27/91 C:SELB:DST


FRosa*03/18/91 C:SICB:DST
03/20/91       P 1 03/l/91        03/  /91 SC:RSIB:DRIS    C:RSIB:DRIS    D:DRIS      C:SELB:DST    C:SICB:DST


SNewberry*
RSIB:DRIS
03/18/91
; -IN 91-XX January xx, 1991 Inadequate


Setpoint Determinations
bt                WDLanning*    BKGrimes*  FRosa*        SNewberry*
  JBdacobson*:t EVImbro*
  02/08/91          02/08/91      02/19/91      02/27/91    03/18/91      03/18/91


and Evaluations
;
                                                -                    IN 91-XX


Many of the findings identified
January xx, 1991 Inadequate Setpoint Determinations and Evaluations


during recent EDSFIs were related to inadequate
to inadequate


setpoint determinations.
Many of the findings identified during recent EDSFIs were related    appropriate


In order to properly determine
setpoint determinations. In order to properly determine         an


an appropriate
be


instrument
instrument setpoint, all associated inaccuracies and tolerances must by ISA


setpoint, all associated
accounted for. Useful guidance for determining setpoints          is  provided


inaccuracies
in


and tolerances
67.04-1982, "Setpoints for Nuclear Safety-Related Instrumentation used        1.105 Nuclear Power Plants' which has been endorsed by Regulatory          Guide


must be accounted
This


for. Useful guidance for determining
Revision 2 - 1986, "Instrument Setpoints for Safety Related Systems".                     for


setpoints
guidance is applicable not Just for instrumentation but is        also    applicable


is provided by ISA 67.04-1982, "Setpoints
certain relays and other control oriented pieces of equipment.


for Nuclear Safety-Related
in


Instrumentation
The setpoint problem has been identified primarily with those instruments        setpoints


used in Nuclear Power Plants' which has been endorsed by Regulatory
which the licensee has determined the setpoints as opposed          to  those


Guide 1.105 Revision 2 -1986, "Instrument
the plant


Setpoints
determined by the NSSS vendor. Those setpoints not contained in                    EDSFIs, technical specifications are also likely to be suspect.        During    recent


for Safety Related Systems".
level    indicators,      diesel


This guidance is applicable
deficiencies in setpoints related to diesel day tank


not Just for instrumentation
low  voltage      shutdown


but is also applicable
air start compressor controllers and alarms, invertor                          been


for certain relays and other control oriented pieces of equipment.
circuitry, degraded grid relays, and diesel overcurrent relays have


The setpoint problem has been identified
identified.


primarily
the NRC


with those instruments
In addition to the deficiencies identified in the setpoints themselves,        magnitude    of


in which the licensee has determined
has determined that licensees are not typically verifying        that    the


the setpoints
calculation      is  indeed


as opposed to those setpoints determined
setpoint drift that was assumed in the original setpoint                  by comparing


by the NSSS vendor. Those setpoints
correct. This verification can be performed by trending, i.e., particularly


not contained
"as found" calibration data to previous "as left"    data.    This    is


in the plant technical
important for the degraded grid setpoints where very tight calibration        are often


specifications
tolerance bands are often required and where very low drift values        has  led to the


are also likely to be suspect. During recent EDSFIs, deficiencies
assumed. Failure to evaluate and account for instrument        drifts


in setpoints
which    could    compromise    the


related to diesel day tank level indicators, diesel air start compressor
operation of equipment outside of acceptable limits


controllers
safety functions of the equipment.


and alarms, invertor low voltage shutdown circuitry, degraded grid relays, and diesel overcurrent
response. If


relays have been identified.
This information notice requires no specific action or writtenplease            contact the


In addition to the deficiencies
you have any questions about the information    in this  notice, technical contact listed below or the appropriate    NRR  project    manager.


identified
Charles E. Rossi, Director


in the setpoints
Division of Operational Events Assessment


themselves, the NRC has determined
that licensees
are not typically
verifying
that the magnitude
of setpoint drift that was assumed in the original setpoint calculation
is indeed correct. This verification
can be performed
by trending, i.e., by comparing"as found" calibration
data to previous "as left" data. This is particularly
important
for the degraded grid setpoints
where very tight calibration
tolerance
bands are often required and where very low drift values are often assumed. Failure to evaluate and account for instrument
drifts has led to the operation
of equipment
outside of acceptable
limits which could compromise
the safety functions
of the equipment.
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
NRR project manager.Charles E. Rossi, Director Division of Operational
===Events Assessment===
Office of Nuclear Reactor Regulation
Office of Nuclear Reactor Regulation


Technical
===Technical Contact:===
 
Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 Attachment:
List of Recently Issued NRC Information
 
Notices*See previous concurrence
 
RPB:ADM C:OGCB:DOEA
 
D:DOEA TechEd CHBerlinger


CERossi 02/ /91 02/ /91 02/ /91 Xrt" RSIB:DRIS
===Jeffrey B. Jacobson, NRR===
                      (301) 492-0996 Attachment:   List of Recently Issued NRC Information Notices


SC:RSIB:DRIS
*See previous concurrence


C: S C:S C:SI JBJacobson*:bt
RPB:ADM        C:OGCB:DOEA    D:DOEA


EVImbro* WD ng mes FRoV-rW SNe rry 02/08/91 02/08/91 024 7/91 02/t7/91 "- / 91O/91 IN 91-XX January xx, 1991 Inadequate
TechEd        CHBerlinger    CERossi


Setpoint Determinations
02/ /91        02/ /91        02/ /91              Xrt"
  RSIB:DRIS      SC:RSIB:DRIS    C:        S                    C:S                C:SI


and Evaluations
WD      ng            mes      FRoV-rW            SNe    rry


Many of the findings identified
JBJacobson*:bt EVImbro*
  02/08/91      02/08/91      024 7/91          02/t7/91 "-      /    91O/91


during recent EDSFIs were related to inadequate
IN 91-XX


setpoint determinations.
January xx, 1991 Inadequate Setpoint Determinations and Evaluations


In order to properly determine
Many of the findings identified during recent EDSFIs were related to inadequate


an appropriate
setpoint determinations. Inorder to properly determine an appropriate


instrument
instrument setpoint, all associated inaccuracies and tolerances must be


setpoint, all associated
accounted for. Guidance for setpoint determinations is given inANSI Standard


inaccuracies
S67.04-1988, 'Setpoints for Nuclear Safety-Related Instrumentation." This for


and tolerances
guidance isapplicable not Just for instrumentation but isalso applicable


must be accounted
certain relays and other control oriented pieces of equipment.


for. Guidance for setpoint determinations
The setpoint problem ismost prevalent for those instruments inwhichdetermined    the


is given in ANSI Standard S67.04-1988, 'Setpoints
licensee has determined the  setpoints  as  opposed  to  those  setpoints


for Nuclear Safety-Related
by the NSSS vendor. Those setpoints not contained in the plant technical


Instrumentation." This guidance is applicable
specifications are also likely to be suspect. During recent EDSFIs,diesel      defi- ciencies in setpoints related  to  diesel  day tank  level  indicators,          air


not Just for instrumentation
start compressor controllers and    alarms,  invertor  low  voltage  shutdown


but is also applicable
circuitry, degraded grid relays, and diesel overcurrent relays have been


for certain relays and other control oriented pieces of equipment.
identified.


The setpoint problem is most prevalent
Inaddition to the deficiencies identified inthe setpoints themselves, the NRC            of


for those instruments
has determined that licensees are not typically verifying that the magnitude    is  indeed


in which the licensee has determined
setpoint drift that was assumed    in the original  setpoint    calculation


the setpoints
correct. This verification can be performed by trending, i.e., by comparing


as opposed to those setpoints
"as found" calibration data to previous "as left" data. This isparticularly


determined
important for the degraded grid rely setpoints where very tight calibration


by the NSSS vendor. Those setpoints
tolerance bands are often required and where very low drift values            are often


not contained
assumed. Failure to evaluate    and  account  for  instrument    drifts  has  led to the


in the plant technical specifications
operation of equipment outside    of  acceptable  limits  which  could  compromise  the


are also likely to be suspect. During recent EDSFIs, defi-ciencies in setpoints
safety functions of the equipment.


related to diesel day tank level indicators, diesel air start compressor
This information notice requires no specific action or writtenplease    response. If


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


and alarms, invertor low voltage shutdown circuitry, degraded grid relays, and diesel overcurrent
technical contact listed below    or  the  appropriate  NRR  project  manager.


relays have been identified.
Charles E. Rossi, Director


In addition to the deficiencies
Division of Operational Events Assessment


identified
in the setpoints
themselves, the NRC has determined
that licensees
are not typically
verifying
that the magnitude
of setpoint drift that was assumed in the original setpoint calculation
is indeed correct. This verification
can be performed
by trending, i.e., by comparing"as found" calibration
data to previous "as left" data. This is particularly
important
for the degraded grid rely setpoints
where very tight calibration
tolerance
bands are often required and where very low drift values are often assumed. Failure to evaluate and account for instrument
drifts has led to the operation
of equipment
outside of acceptable
limits which could compromise
the safety functions
of the equipment.
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
NRR project manager.Charles E. Rossi, Director Division of Operational
===Events Assessment===
Office of Nuclear Reactor Regulation
Office of Nuclear Reactor Regulation


Technical
===Technical Contact:===
 
Contact: Jeffrey B. Jacobson, NRR (301) 492-0996 Attachment:
List of Recently Issued NRC Information
 
Notices RPB:ADM C:OGCB:DOEA


D:DOEA TechEd CHBerlinger
===Jeffrey B.Jacobson, NRR===
                      (301) 492-0996 Attachment: List of Recently Issued NRC Information Notices


CERossi 02/ /91 02/ /91 02/ /91 RSIB: SC:RX RIS C:RSIB:DRIS
RPB:ADM        C:OGCB:DOEA      D:DOEA


D:DRIS C:SELB:DST
TechEd          CHBerlinger    CERossi


C:SICB:DST
02/ /91        02/ /91        02/ /91 RSIB:          SC:RX RIS      C:RSIB:DRIS      D:DRIS        C:SELB:DST    C:SICB:DST


JBJac 6n:bt EVIm 'J>' WDLanning
JBJac 6n:bt EVIm 'J>'           WDLanning         BKGrimes      FRosa          SNewberry


BKGrimes FRosa SNewberry 020 A' 02/djz1 02/ /91 02/ /91 02/ /91 02/ /91}}
020 A'         02/djz1         02/ /91           02/ /91       02/ /91       02/ /91}}


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

Revision as of 02:25, 24 November 2019

Deficiencies Identifie During Electrical Distribution System Functional Inspections
ML031190636
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, 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, Crane  
Issue date: 04/15/1991
From: Rossi C
Office of Nuclear Reactor Regulation
To:
References
IN-91-029, NUDOCS 9104090124
Download: ML031190636 (10)
v • d • e


4 A

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 April 15, 1991 NRC INFORMATION NOTICE NO. 91-29: DEFICIENCIES IDENTIFIED DURING ELECTRICAL

DISTRIBUTION SYSTEM FUNCTIONAL INSPECTIONS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is intended to alert addressees to deficiencies identi- fied during recently performed electrical distribution system functional

inspections (EDSFIs). It is expected that recipients will review the informa- tion for applicability to their facilities and consider actions, as appropri- ate, 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

During multidisciplinary inspections, the U.S. Nuclear Regulatory Commission

(NRC) has identified many deficiencies related to tWeelectrical distribution

system. To address these deficiencies, the NRC has developed an inspection to

specifically evaluate the electrical distribution system. During the last

year, the NRC completed eight EDSFIs, performing at least one in each of the

five NRC geographical regions. During these inspections, the staff found

several common deficiencies in the licensees' programs and in the electrical

distribution systems as designed and configured at each plant. These deficien- cies included inadequate ac voltages at the 480 Vac and 120 Vac distribution

levels, inadequate procedures to test circuit breakers, and inadequate determi- nations and evaluations of setpoints.

Discussion:

Inadequate Voltage

During inspections conducted at the San Onofre Nuclear Generating Station

(Inspection Reports 50-361/89-200 and 50-362/89-200), the Susquehanna Steam

Electric Station (Inspection Reports 50-387/90-200 and 50-388/90-200), and the

9104090124

'J

IN 91-29 April 15, 1991 Waterford Steam Electric Station (Inspection Report 50-382/90-23), the staff

found that, under certain conditions, the voltage available at the safety buses

would be inadequate to Operate safety-related loads and associated equipment.

These conditions could occur when the plan~t's electrical distribution systems

were being supplied from an offsite grid that had become degraded but that

continued to supply voltages that remained above the setpoints at which the

degraded grid relays would be activated.

At San Onofre, the numerous voltage drops throughout the system could cause the

voltage to 120 Vaciontactors to drop below the-voltage range for which these

contactors were certified as acceptable by their manufacturers. To resolve

this problem the licensee has performed testing that established a lower

acceptable voltage range for this equipment.

At Susquehanna, the degraded grid relay setpoint'was'set at 84 percent on the

4160 Yac buses. Th'i's setpoint could have allowed inadequate voltage to be

-delivered to numerous safety-related loads at both the 480 Vac and 120 Vac

levels. The licensee calculated that setpoints'of at least 93 percent would be

required to ensure adequate voTtage to all safety-related equipment. To

resolve this problem, the lice'isee has raised the setpoints of the degraded

grid relays and has initiated a modification to install 120 Vac regulating

transformers.

At the Waterford nuclear plant, the degraded grid relays were set at

87.5 percent'as sensed on the'4160 Vac buses. :Although this setting was found

to be marginally adequate-'for-equipment connected to the 4160 Vac buses, the

setting was too low to ensure that adequate v6ltage would'be maintained at the

480 Vac and 120 Vac levels. The licensee is 6e4aluating solutions to this

problem and has instituted a procedure- to manually'separate from the grid if

the voltage falls to unacceptable levels but remains above the relay setpoints.

The function of the degraded grid relays is to en'sure that adequate voltage is

available tooperate all Class lE loads at all distribution levels. In order

to ensure-that all required'Class E 'loads will remain operable during degraded

voltage conditions, some licensees are currently'reanalyzing the basis for the

degraded grid relay setpoints. The new analyses consider all required Class 1E

loads and include the assumption that the voltage on the buses being sensed by

these relays can remain at a level just above the relay setpoints.

Inadequate Circuit Breaker Testing Procedures

During recent EDSFIs ahd previously on other NRC inspections, the staff identi- fied repetitive deficiencies in licensees' programs to test circuit breakers.

These deficiencies included inadequate procedures, inadequate test acceptance

criteria, inadequate test equipment, and inadequate control of testing. At the

Susquehanna plant (Inspection Reports 50-387/90-200 and 50-388/90-200), the

staff found that the licensee was testing dc molded case circuit breakers with

a procedure written for testing ac breakers. The licensee had not established

specific acceptance criteria for the dc breakers.

IN 91-29 April 15, 1991 At the Shearon Harris Nuclear Power Plant (Inspection Report 50-400/90-200),

the staff identified that the licensee was.testing molded case circuit breakers

against National Electrical Manufacturers Association (NEMA),acceptance crite- ria, which were less stringent than the manufacturer's time-current curves for

these breakers. In addition, the staff identified that the licensee was

testing 480 V air circuit breakers with test equipment that applied a test

signal (secondary injection) to the solid state trip units in the circuit

breakers. Although this method adequately verified that the trip units func- tioned properly, it did not verify that the breaker's current transformer

functioned properly or that the wiring and connectors were adequate between the

current transformer and the solid state trip units. Other licensees have

performed testing by primary current injection or by individually checking each

component of the circuit breaker, including the wiring and connectors to

demonstrate that the circuit breaker functions properly.

Inadequate Determinations and Evaluations of Setpoints

Many of the findings identified during recent EDSFIs were related to inadequate

setpoint determinations. Useful guidance for determining setpoints is provided

by Instrument Society of America Standard 67.04-1982, "Setpoints for Nuclear

Safety-Related Instrumentation used in Nuclear Power Plants," which the NRC

staff has endorsed by Regulatory Guide 1.105 Revision 2 - 1986, "Instrument

Setpoints for Safety-Related Systems." This guidance applies both to process

instrumentation and, in part, to certain relays that perform a safety function.

Some licensees have operated equipment outside of acceptable limits because

they did not determine proper setpoints and did not evaluate and account for

instrument drift. Operating the equipment under these conditions could

compromise the safety functions of the equipment. The staff has identified

these circumstances primarily for those instruments in which the licensee has

determined the setpoints as opposed to those instruments for which the

setpoints were determined by the architect/engineer or the nuclear safety

system supplier. Those setpoints not contained in the plant technical specifi- cations were also more frequently found to be deficient. During recent EDSFIs, the staff identified deficiencies in setpoints for diesel day tank level

indicators, diesel air start compressor controllers and alarms, inverter low

voltage shutdown circuitry, degraded grid relays, and diesel overcurrent

relays.

In addition to identifying deficiencies in the setpoints themselves, the NRC

has determined that not all the licensees are typically verifying that the

magnitude of instrument drift that was assumed in the original setpoint calcu- lation coincides with the magnitude of drift observed in the plant. Some

licensees have corrected this deficiency by verifying the magnitude of instru- ment drift by trending, (comparing "as found" calibration data to previous "as

left" data). This is particularly important for the degraded grid relay

setpoints, which often require very tight calibration tolerance bands, and for

which very low drift values are often assumed.

v- IN 91-29 April 15, 1991 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 NRR project manager.

Charles E. Rossi, eirector

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Jeffrey B. Jacobson, NRR

(301) 492-0996 Attachment: List of Recently Issued NRC Information Notices

i

Attachment 1 IN 91-29 April 15, 1991 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

91-28 Cracking in Feedwater 04/15/91 All holders of OLs or

System Piping CPs for pressurized

water reactors (PWRs).

91-27 Incorrect Rotation of 04/10/91 All holders of OLs or

Positive Displacement Pump CPs for nuclear power

reactors.

89-90, Pressurizer Safety Valve 04/10/91 All holders of OLs or

Supp. 1 Lift Setpoint Shift CPs for nuclear power

reactors.

91-26 Potential Nonconservative 04/02/91 All fuel cycle licensees

Errors in the Working Format and other licensees, in- Hansen-Roach Cross-Section cluding all holders of

Set Provided with The Keno operating licenses for

and Scale Codes nuclear power reactors, who use physics codes to

support criticality

safety in the use of

fissile material.

91-25 Commercial-Grade Structural 04/01/91 All holders of OLs or

Framing Components Supplied CPs for nuclear power

As Nuclear Safety-Related reactors.

Equipment

91-24 Recent Operating Experience 03/26/91 All holders of OLs or

Involving Reactor Operation CPs for nuclear power, Without A Licensed Reactor test, and research re- Operator or Senior Reactor actors, and all Part 55 Operator Present in the licensed operators.

Control Room

91-23 Accidental Radiation Over- 03/26/91 All Nuclear Regulatory

exposures to Personnel Due to Commission (NRC) licens- Industrial Radiography Acces- ees authorized to use

sory Equipment Malfunctions sealed sources for indus- trial radiography.

OL = Operating License

CP = Construction Permit

IN 91-29 April 15, 1991 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 NRR project manager.

O6ginal agen& by

Charles E. Ross!

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Jeffrey B. Jacobson, NRR

(301) 492-0996 Attachment: List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCES
  • C/OGCB:DOEA:NRR*RPB:ADM *C/SICB:DST:NRR *C/SELB:DST:NRR

CHBerlinger TechEd SNewberry FRosa

04/ fI9 04/08/91 03/20/91 03/18/91 03/18/91 OGC :DOEA: RR *RSIB:DRIS:NRR *SC/RSIB:DRIS:NRR*C/RSIB:DRIS:NRR *D/DRIS:NRR

PCWen JBJacobson:bt EVImbro WDLanning BKGrimes

04/ /91 02/08/91 02/08/91 02/19/91 02/27/91

  • - I IN 91-XX

April xx, 1991 If

no specific action or written response.

This information notice requires information in this notice, please contact the

you have any questions about the the appropriate NRR project manager.

technical contact listed below or

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Jeffrey B. Jacobson, NRR

(301) 492-0996 Notices

Attachment: List of Recently Issued NRC Information

  • SEE PREVIOUS CONCURRENCES *C/SICB:DST:NRR *C/SELB:DST:NRR

T*RPB:Ad SNewBerry FRosa

D/DOEA:NRR C/OGCB:DO

CERossi Y- CHBerling rjw TechEd 03/18/91

03/20/91 03/18/91

04/ /91 04/8/91 *D/DRIS:NRR

,cCB:DOEA:NRR *RSIB:DRIS:NRR *SC/RSIB:DRIS:NRR*C/RSIB:DRISNRR

WMLanning BKGrimes

JBJacobson:bt EVImbro 02/27/91

4CvPvWen 02/08/91 02/19/91

04/cl/91 02/08/91

IN 91-XX

March xx, 1991 Inadequate Determinations and Evaluations of Setpoints

Many of the findings identified during recent EDSFIs related to inadequate

setpoint determinations. Useful guidance for determining setpoints is provided

by Instrument Society of America Standard 67.04-1982, "Setpoints for Nuclear

Safety-Related Instrumentation used in Nuclear Power Plants," which the NRC

staff has endorsed by Regulatory Guide 1.105 Revision 2 - 1986, "Instrument

Setpoints for Safety-Related Systems." This guidance applies both to process

instrumentation and, in part, to certain relays that perform a safety function.

did

Licensees have operated equipment outside of acceptable limits because they

not determine proper setpoints and did not evaluate and account for instrument

drifts. Operating the equipment under these conditions could compromise the

safety functions of the equipment. The staff has identified these circum- stances primarily for those instruments in which the licensee has determined

the setpoints as opposed to those instruments for which the setpoints were

determined by the architect/engineer or the nuclear safety system supplier.

Those setpoints not contained in the plant technical specifications were also

more frequently found to be deficient. During recent EDSFIs, the staff

identified deficiencies in setpoints for diesel day tank level indicators, diesel air start compressor controllers and alarms, inverter low voltage

shutdown circuitry, degraded grid relays, and diesel overcurrent relays.

NRC

In addition to identifying deficiencies in the setpoints themselves, the

has determined that licensees are not typically verifying that the magnitude

of instrument drift that was assumed in the original setpoint calculation

coincides with the magnitude of drift observed in the plant. Licenseefound" can

verify the magnitude of instrument drift by trending, (comparing 'as

calibration data to previous 'as left" data). This is particularly important

for the degraded grid relay setpoints, which often require very tight calibra- tion tolerance bands, and for which very low drift values are often assumed.

If

This information notice requires no specific action or written response. contact the

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

technical contact listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Jeffrey B. Jacobson, NRR

(301) 492-0996 Attachment: List of Recently Issued NRC Information Notices

RPB:ADM C:OGCB:UOEA D:DOEA *See previous concurrence

TechEd* i m Ja CHBerlinger CERossi

03/20/91 P 1 03/l/91 03/ /91 SC:RSIB:DRIS C:RSIB:DRIS D:DRIS C:SELB:DST C:SICB:DST

RSIB:DRIS

bt WDLanning* BKGrimes* FRosa* SNewberry*

JBdacobson*:t EVImbro*

02/08/91 02/08/91 02/19/91 02/27/91 03/18/91 03/18/91

- IN 91-XX

January xx, 1991 Inadequate Setpoint Determinations and Evaluations

to inadequate

Many of the findings identified during recent EDSFIs were related appropriate

setpoint determinations. In order to properly determine an

be

instrument setpoint, all associated inaccuracies and tolerances must by ISA

accounted for. Useful guidance for determining setpoints is provided

in

67.04-1982, "Setpoints for Nuclear Safety-Related Instrumentation used 1.105 Nuclear Power Plants' which has been endorsed by Regulatory Guide

This

Revision 2 - 1986, "Instrument Setpoints for Safety Related Systems". for

guidance is applicable not Just for instrumentation but is also applicable

certain relays and other control oriented pieces of equipment.

in

The setpoint problem has been identified primarily with those instruments setpoints

which the licensee has determined the setpoints as opposed to those

the plant

determined by the NSSS vendor. Those setpoints not contained in EDSFIs, technical specifications are also likely to be suspect. During recent

level indicators, diesel

deficiencies in setpoints related to diesel day tank

low voltage shutdown

air start compressor controllers and alarms, invertor been

circuitry, degraded grid relays, and diesel overcurrent relays have

identified.

the NRC

In addition to the deficiencies identified in the setpoints themselves, magnitude of

has determined that licensees are not typically verifying that the

calculation is indeed

setpoint drift that was assumed in the original setpoint by comparing

correct. This verification can be performed by trending, i.e., particularly

"as found" calibration data to previous "as left" data. This is

important for the degraded grid setpoints where very tight calibration are often

tolerance bands are often required and where very low drift values has led to the

assumed. Failure to evaluate and account for instrument drifts

which could compromise the

operation of equipment outside of acceptable limits

safety functions of the equipment.

response. If

This information notice requires no specific action or writtenplease contact the

you have any questions about the information in this notice, technical contact listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Jeffrey B. Jacobson, NRR

(301) 492-0996 Attachment: List of Recently Issued NRC Information Notices

  • See previous concurrence

RPB:ADM C:OGCB:DOEA D:DOEA

TechEd CHBerlinger CERossi

02/ /91 02/ /91 02/ /91 Xrt"

RSIB:DRIS SC:RSIB:DRIS C: S C:S C:SI

WD ng mes FRoV-rW SNe rry

JBJacobson*:bt EVImbro*

02/08/91 02/08/91 024 7/91 02/t7/91 "- / 91O/91

IN 91-XX

January xx, 1991 Inadequate Setpoint Determinations and Evaluations

Many of the findings identified during recent EDSFIs were related to inadequate

setpoint determinations. Inorder to properly determine an appropriate

instrument setpoint, all associated inaccuracies and tolerances must be

accounted for. Guidance for setpoint determinations is given inANSI Standard

S67.04-1988, 'Setpoints for Nuclear Safety-Related Instrumentation." This for

guidance isapplicable not Just for instrumentation but isalso applicable

certain relays and other control oriented pieces of equipment.

The setpoint problem ismost prevalent for those instruments inwhichdetermined the

licensee has determined the setpoints as opposed to those setpoints

by the NSSS vendor. Those setpoints not contained in the plant technical

specifications are also likely to be suspect. During recent EDSFIs,diesel defi- ciencies in setpoints related to diesel day tank level indicators, air

start compressor controllers and alarms, invertor low voltage shutdown

circuitry, degraded grid relays, and diesel overcurrent relays have been

identified.

Inaddition to the deficiencies identified inthe setpoints themselves, the NRC of

has determined that licensees are not typically verifying that the magnitude is indeed

setpoint drift that was assumed in the original setpoint calculation

correct. This verification can be performed by trending, i.e., by comparing

"as found" calibration data to previous "as left" data. This isparticularly

important for the degraded grid rely setpoints where very tight calibration

tolerance bands are often required and where very low drift values are often

assumed. Failure to evaluate and account for instrument drifts has led to the

operation of equipment outside of acceptable limits which could compromise the

safety functions of the equipment.

This information notice requires no specific action or writtenplease response. If

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

technical contact listed below or the appropriate NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Jeffrey B.Jacobson, NRR

(301) 492-0996 Attachment: List of Recently Issued NRC Information Notices

RPB:ADM C:OGCB:DOEA D:DOEA

TechEd CHBerlinger CERossi

02/ /91 02/ /91 02/ /91 RSIB: SC:RX RIS C:RSIB:DRIS D:DRIS C:SELB:DST C:SICB:DST

JBJac 6n:bt EVIm 'J>' WDLanning BKGrimes FRosa SNewberry

020 A' 02/djz1 02/ /91 02/ /91 02/ /91 02/ /91


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