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

From kanterella
Jump to navigation Jump to search
← Older editNewer edit →
VisualWikitext
Created page by program invented by StriderTol
Created page by program invented by StriderTol
Line 14: Line 14:
| page count = 10
| page count = 10
}}
}}
{{#Wiki_filter:4AUNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555April 15, 1991NRC INFORMATION NOTICE NO. 91-29: DEFICIENCIES IDENTIFIED DURING ELECTRICALDISTRIBUTION SYSTEM FUNCTIONAL INSPECTIONS
{{#Wiki_filter: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==
==Addressees==
:All holders of operating licenses or construction permits for nuclear powerreactors.
:
All holders of operating
 
licenses or construction
 
permits for nuclear power reactors.


==Purpose==
==Purpose==
:This information notice is intended to alert addressees to deficiencies identi-fied during recently performed electrical distribution system functionalinspections (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 thisinformation notice do not constitute NRC requirements; therefore, no specificaction or written response is required.
: 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 91-27 89-90, Supp. 1 91-26 91-25 91-24 91-23 Cracking in Feedwater System Piping Incorrect
 
Rotation of Positive Displacement
 
Pump Pressurizer
 
Safety Valve Lift Setpoint Shift Potential
 
===Nonconservative===
Errors in the Working Format Hansen-Roach
 
Cross-Section
 
Set Provided with The Keno and Scale Codes Commercial-Grade
 
Structural
 
Framing Components
 
Supplied As Nuclear Safety-Related
 
Equipment Recent Operating
 
Experience
 
Involving
 
Reactor Operation Without A Licensed Reactor Operator or Senior Reactor Operator Present in the Control Room Accidental
 
Radiation
 
Over-exposures
 
to Personnel
 
Due to Industrial
 
Radiography
 
Acces-sory Equipment
 
===Malfunctions===
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
 
licenses for nuclear power reactors, who use physics codes to support criticality
 
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.
 
03/26/91 All Nuclear Regulatory
 
Commission (NRC) licens-ees authorized
 
to use 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 04/ fI9 OGC :DOEA: RR PCWen 04/ /91 CONCURRENCES
 
*C/OGCB:DOEA:NRR*RPB:ADM
 
*C/SICB:DST:NRR
 
CHBerlinger
 
TechEd SNewberry 04/08/91 03/20/91 03/18/91*RSIB:DRIS:NRR
 
*SC/RSIB:DRIS:NRR*C/RSIB:DRIS:NRR
 
JBJacobson:bt
 
EVImbro WDLanning 02/08/91 02/08/91 02/19/91*C/SELB:DST:NRR
 
FRosa 03/18/91*D/DRIS:NRR
 
BKGrimes 02/27/91
*- I IN 91-XX April xx, 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, Director Division of Operational
 
===Events Assessment===
Office of Nuclear Reactor Regulation
 
Technical
 
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
 
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.In addition to identifying
 
deficiencies
 
in the setpoints
 
themselves, the NRC 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. Licensee can verify the magnitude
 
of instrument
 
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 calibra-tion tolerance
 
bands, and for which very low drift values are often assumed.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
 
Technical
 
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
 
EVImbro*02/08/91 C:RSIB:DRIS
 
WDLanning*
02/19/91 D:DRIS BKGrimes*02/27/91 C:SELB:DST
 
FRosa*03/18/91 C:SICB:DST
 
SNewberry*
03/18/91
; -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.
 
In order to properly determine
 
an appropriate
 
instrument
 
setpoint, all associated
 
inaccuracies
 
and tolerances
 
must be accounted
 
for. Useful guidance for determining
 
setpoints
 
is provided by ISA 67.04-1982, "Setpoints
 
for Nuclear Safety-Related
 
Instrumentation
 
used in Nuclear Power Plants' which has been endorsed by Regulatory
 
Guide 1.105 Revision 2 -1986, "Instrument
 
Setpoints
 
for Safety Related Systems".
 
This guidance is applicable
 
not Just for instrumentation
 
but is also applicable
 
for certain relays and other control oriented pieces of equipment.
 
The setpoint problem has been identified
 
primarily
 
with those instruments
 
in which the licensee has determined
 
the setpoints
 
as opposed to those setpoints determined
 
by the NSSS vendor. Those setpoints
 
not contained
 
in the plant technical
 
specifications
 
are also likely to be suspect. During recent EDSFIs, deficiencies
 
in setpoints
 
related to diesel day tank level indicators, diesel air start compressor
 
controllers
 
and alarms, invertor low voltage shutdown circuitry, degraded grid relays, and diesel overcurrent
 
relays have been identified.
 
In addition to the deficiencies
 
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 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
 
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 JBJacobson*:bt
 
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
 
Setpoint Determinations
 
and Evaluations
 
Many of the findings identified
 
during recent EDSFIs were related to inadequate
 
setpoint determinations.
 
In order to properly determine
 
an appropriate
 
instrument
 
setpoint, all associated
 
inaccuracies
 
and tolerances
 
must be accounted
 
for. Guidance for setpoint determinations
 
is given in ANSI Standard S67.04-1988, 'Setpoints
 
for Nuclear Safety-Related
 
Instrumentation." This guidance is applicable
 
not Just for instrumentation
 
but is also applicable
 
for certain relays and other control oriented pieces of equipment.
 
The setpoint problem is most prevalent
 
for those instruments
 
in which the licensee has determined
 
the setpoints
 
as opposed to those setpoints
 
determined
 
by the NSSS vendor. Those setpoints
 
not contained
 
in the plant technical specifications
 
are also likely to be suspect. During recent EDSFIs, defi-ciencies in setpoints
 
related to diesel day tank level indicators, diesel air start compressor
 
controllers
 
and alarms, invertor low voltage shutdown circuitry, degraded grid relays, and diesel overcurrent
 
relays have been identified.
 
In addition to the deficiencies
 
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


==Description of Circumstances==
NRR project manager.Charles E. Rossi, Director Division of Operational
:During multidisciplinary inspections, the U.S. Nuclear Regulatory Commission(NRC) has identified many deficiencies related to tWeelectrical distributionsystem. To address these deficiencies, the NRC has developed an inspection tospecifically evaluate the electrical distribution system. During the lastyear, the NRC completed eight EDSFIs, performing at least one in each of thefive NRC geographical regions. During these inspections, the staff foundseveral common deficiencies in the licensees' programs and in the electricaldistribution systems as designed and configured at each plant. These deficien-cies included inadequate ac voltages at the 480 Vac and 120 Vac distributionlevels, inadequate procedures to test circuit breakers, and inadequate determi-nations and evaluations of setpoints.Discussion:Inadequate VoltageDuring inspections conducted at the San Onofre Nuclear Generating Station(Inspection Reports 50-361/89-200 and 50-362/89-200), the Susquehanna SteamElectric Station (Inspection Reports 50-387/90-200 and 50-388/90-200), and the9104090124
' JIN 91-29April 15, 1991 Waterford Steam Electric Station (Inspection Report 50-382/90-23), the stafffound that, under certain conditions, the voltage available at the safety buseswould be inadequate to Operate safety-related loads and associated equipment.These conditions could occur when the plan~t's electrical distribution systemswere being supplied from an offsite grid that had become degraded but thatcontinued to supply voltages that remained above the setpoints at which thedegraded grid relays would be activated.At San Onofre, the numerous voltage drops throughout the system could cause thevoltage to 120 Vaciontactors to drop below the-voltage range for which thesecontactors were certified as acceptable by their manufacturers. To resolvethis problem the licensee has performed testing that established a loweracceptable voltage range for this equipment.At Susquehanna, the degraded grid relay setpoint'was'set at 84 percent on the4160 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 Vaclevels. The licensee calculated that setpoints'of at least 93 percent would berequired to ensure adequate voTtage to all safety-related equipment. Toresolve this problem, the lice'isee has raised the setpoints of the degradedgrid relays and has initiated a modification to install 120 Vac regulatingtransformers.At the Waterford nuclear plant, the degraded grid relays were set at87.5 percent'as sensed on the'4160 Vac buses. :Although this setting was foundto be marginally adequate-'for-equipment connected to the 4160 Vac buses, thesetting was too low to ensure that adequate v6ltage would'be maintained at the480 Vac and 120 Vac levels. The licensee is 6e4aluating solutions to thisproblem and has instituted a procedure- to manually'separate from the grid ifthe 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 isavailable tooperate all Class lE loads at all distribution levels. In orderto ensure-that all required' Class E 'loads will remain operable during degradedvoltage conditions, some licensees are currently'reanalyzing the basis for thedegraded grid relay setpoints. The new analyses consider all required Class 1Eloads and include the assumption that the voltage on the buses being sensed bythese relays can remain at a level just above the relay setpoints.Inadequate Circuit Breaker Testing ProceduresDuring 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 acceptancecriteria, inadequate test equipment, and inadequate control of testing. At theSusquehanna plant (Inspection Reports 50-387/90-200 and 50-388/90-200), thestaff found that the licensee was testing dc molded case circuit breakers witha procedure written for testing ac breakers. The licensee had not establishedspecific acceptance criteria for the dc breakers.


IN 91-29April 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 breakersagainst National Electrical Manufacturers Association (NEMA),acceptance crite-ria, which were less stringent than the manufacturer's time-current curves forthese breakers. In addition, the staff identified that the licensee wastesting 480 V air circuit breakers with test equipment that applied a testsignal (secondary injection) to the solid state trip units in the circuitbreakers. Although this method adequately verified that the trip units func-tioned properly, it did not verify that the breaker's current transformerfunctioned properly or that the wiring and connectors were adequate between thecurrent transformer and the solid state trip units. Other licensees haveperformed testing by primary current injection or by individually checking eachcomponent of the circuit breaker, including the wiring and connectors todemonstrate that the circuit breaker functions properly.Inadequate Determinations and Evaluations of SetpointsMany of the findings identified during recent EDSFIs were related to inadequatesetpoint determinations. Useful guidance for determining setpoints is providedby Instrument Society of America Standard 67.04-1982, "Setpoints for NuclearSafety-Related Instrumentation used in Nuclear Power Plants," which the NRCstaff has endorsed by Regulatory Guide 1.105 Revision 2 -1986, "InstrumentSetpoints for Safety-Related Systems." This guidance applies both to processinstrumentation and, in part, to certain relays that perform a safety function.Some licensees have operated equipment outside of acceptable limits becausethey did not determine proper setpoints and did not evaluate and account forinstrument drift. Operating the equipment under these conditions couldcompromise the safety functions of the equipment. The staff has identifiedthese circumstances primarily for those instruments in which the licensee hasdetermined the setpoints as opposed to those instruments for which thesetpoints were determined by the architect/engineer or the nuclear safetysystem 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 levelindicators, diesel air start compressor controllers and alarms, inverter lowvoltage shutdown circuitry, degraded grid relays, and diesel overcurrentrelays.In addition to identifying deficiencies in the setpoints themselves, the NRChas determined that not all the licensees are typically verifying that themagnitude of instrument drift that was assumed in the original setpoint calcu-lation coincides with the magnitude of drift observed in the plant. Somelicensees have corrected this deficiency by verifying the magnitude of instru-ment drift by trending, (comparing "as found" calibration data to previous "asleft" data). This is particularly important for the degraded grid relaysetpoints, which often require very tight calibration tolerance bands, and forwhich very low drift values are often assumed.
===Events Assessment===
Office of Nuclear Reactor Regulation


v-IN 91-29April 15, 1991 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact thetechnical contact listed below or the appropriate NRR project manager.Charles E. Rossi, eirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor Regulation
Technical


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


Attachment 1IN 91-29April 15, 1991 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to91-2891-2789-90,Supp. 191-2691-2591-2491-23Cracking in FeedwaterSystem PipingIncorrect Rotation ofPositive Displacement PumpPressurizer Safety ValveLift Setpoint ShiftPotential NonconservativeErrors in the Working FormatHansen-Roach Cross-SectionSet Provided with The Kenoand Scale CodesCommercial-Grade StructuralFraming Components SuppliedAs Nuclear Safety-RelatedEquipmentRecent Operating ExperienceInvolving Reactor OperationWithout A Licensed ReactorOperator or Senior ReactorOperator Present in theControl RoomAccidental Radiation Over-exposures to Personnel Due toIndustrial Radiography Acces-sory Equipment Malfunctions04/15/91 All holders of OLs orCPs for pressurizedwater reactors (PWRs).04/10/91 All holders of OLs orCPs for nuclear powerreactors.04/10/91 All holders of OLs orCPs for nuclear powerreactors.04/02/91 All fuel cycle licenseesand other licensees, in-cluding all holders ofoperating licenses fornuclear power reactors,who use physics codes tosupport criticalitysafety in the use offissile material.04/01/91 All holders of OLs orCPs for nuclear powerreactors.03/26/91 All holders of OLs orCPs for nuclear power,test, and research re-actors, and all Part 55licensed operators.03/26/91 All Nuclear RegulatoryCommission (NRC) licens-ees authorized to usesealed sources for indus-trial radiography.OL = Operating LicenseCP = Construction Permit
Notices RPB:ADM C:OGCB:DOEA


IN 91-29April 15, 1991 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact thetechnical contact listed below or the appropriate NRR project manager.O6ginal agen& byCharles E. Ross!Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor Regulation
D:DOEA TechEd CHBerlinger


===Technical Contact:===
CERossi 02/ /91 02/ /91 02/ /91 RSIB: SC:RX RIS C:RSIB:DRIS
Jeffrey B. Jacobson, NRR(301) 492-0996Attachment:List of Recently Issued NRC Information Notices*SEE PREVIOUS04/ fI9OGC :DOEA: RRPCWen04/ /91CONCURRENCES*C/OGCB:DOEA:NRR*RPB:ADM *C/SICB:DST:NRRCHBerlinger TechEd SNewberry04/08/91 03/20/91 03/18/91*RSIB:DRIS:NRR *SC/RSIB:DRIS:NRR*C/RSIB:DRIS:NRRJBJacobson:bt EVImbro WDLanning02/08/91 02/08/91 02/19/91*C/SELB:DST:NRRFRosa03/18/91*D/DRIS:NRRBKGrimes02/27/91
*- I IN 91-XXApril xx, 1991 This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact thetechnical contact listed below or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor Regulation


===Technical Contact:===
D:DRIS C:SELB:DST
Jeffrey B. Jacobson, NRR(301) 492-0996List of Recently Issued NRC Information NoticesAttachment:*SEE PREVIOUS CONCURRENCES *C/SICB:DST:NRRD/DOEA:NRR C/OGCB:DO T*RPB:Ad SNewBerryCERossi Y- CHBerling rjw TechEd04/ /91 04/8/91 03/20/91 03/18/91,c CB:DOEA:NRR *RSIB:DRIS:NRR *SC/RSIB:DRIS:NRR*C/RSIB:DRISNRR4CvPvWen JBJacobson:bt EVImbro WMLanning04/cl/91 02/08/91 02/08/91 02/19/91*C/SELB:DST:NRRFRosa03/18/91*D/DRIS:NRRBKGrimes02/27/91 IN 91-XXMarch xx, 1991 Inadequate Determinations and Evaluations of SetpointsMany of the findings identified during recent EDSFIs related to inadequatesetpoint determinations. Useful guidance for determining setpoints is providedby Instrument Society of America Standard 67.04-1982, "Setpoints for NuclearSafety-Related Instrumentation used in Nuclear Power Plants," which the NRCstaff has endorsed by Regulatory Guide 1.105 Revision 2 -1986, "InstrumentSetpoints for Safety-Related Systems." This guidance applies both to processinstrumentation and, in part, to certain relays that perform a safety function.Licensees have operated equipment outside of acceptable limits because they didnot determine proper setpoints and did not evaluate and account for instrumentdrifts. Operating the equipment under these conditions could compromise thesafety functions of the equipment. The staff has identified these circum-stances primarily for those instruments in which the licensee has determinedthe setpoints as opposed to those instruments for which the setpoints weredetermined by the architect/engineer or the nuclear safety system supplier.Those setpoints not contained in the plant technical specifications were alsomore frequently found to be deficient. During recent EDSFIs, the staffidentified deficiencies in setpoints for diesel day tank level indicators,diesel air start compressor controllers and alarms, inverter low voltageshutdown circuitry, degraded grid relays, and diesel overcurrent relays.In addition to identifying deficiencies in the setpoints themselves, the NRChas determined that licensees are not typically verifying that the magnitudeof instrument drift that was assumed in the original setpoint calculationcoincides with the magnitude of drift observed in the plant. Licensee canverify the magnitude of instrument drift by trending, (comparing 'as found"calibration data to previous 'as left" data). This is particularly importantfor the degraded grid relay setpoints, which often require very tight calibra-tion tolerance bands, and for which very low drift values are often assumed.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact thetechnical contact listed below or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor Regulation


===Technical Contact:===
C:SICB:DST
Jeffrey B. Jacobson, NRR(301) 492-0996Attachment:RPB:ADMTechEd* imJa03/20/91 PRSIB:DRISJBdacobson*:t02/08/91List of Recently Issued NRC Information NoticesC:OGCB:UOEA D:DOEA *See previous cCHBerlinger CERossi1 03/l/91 03/ /91oncurrencebtSC:RSIB:DRISEVImbro*02/08/91C:RSIB:DRISWDLanning*02/19/91D:DRISBKGrimes*02/27/91C:SELB:DSTFRosa*03/18/91C:SICB:DSTSNewberry*03/18/91
; -IN 91-XXJanuary xx, 1991 Inadequate Setpoint Determinations and EvaluationsMany of the findings identified during recent EDSFIs were related to inadequatesetpoint determinations. In order to properly determine an appropriateinstrument setpoint, all associated inaccuracies and tolerances must beaccounted for. Useful guidance for determining setpoints is provided by ISA67.04-1982, "Setpoints for Nuclear Safety-Related Instrumentation used inNuclear Power Plants' which has been endorsed by Regulatory Guide 1.105Revision 2 -1986, "Instrument Setpoints for Safety Related Systems". Thisguidance is applicable not Just for instrumentation but is also applicable forcertain relays and other control oriented pieces of equipment.The setpoint problem has been identified primarily with those instruments inwhich the licensee has determined the setpoints as opposed to those setpointsdetermined by the NSSS vendor. Those setpoints not contained in the planttechnical specifications are also likely to be suspect. During recent EDSFIs,deficiencies in setpoints related to diesel day tank level indicators, dieselair start compressor controllers and alarms, invertor low voltage shutdowncircuitry, degraded grid relays, and diesel overcurrent relays have beenidentified.In addition to the deficiencies identified in the setpoints themselves, the NRChas determined that licensees are not typically verifying that the magnitude ofsetpoint drift that was assumed in the original setpoint calculation is indeedcorrect. This verification can be performed by trending, i.e., by comparing"as found" calibration data to previous "as left" data. This is particularlyimportant for the degraded grid setpoints where very tight calibrationtolerance bands are often required and where very low drift values are oftenassumed. Failure to evaluate and account for instrument drifts has led to theoperation of equipment outside of acceptable limits which could compromise thesafety functions of the equipment.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact thetechnical contact listed below or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor Regulation


===Technical Contact:===
JBJac 6n:bt EVIm 'J>' WDLanning
Jeffrey B. Jacobson, NRR(301) 492-0996Attachment: List of Recently Issued NRC Information Notices*See previous concurrenceRPB:ADM C:OGCB:DOEA D:DOEATechEd CHBerlinger CERossi02/ /91 02/ /91 02/ /91 Xrt"RSIB:DRIS SC:RSIB:DRIS C: S C:S C:SIJBJacobson*:bt EVImbro* WD ng mes FRoV-rW SNe rry02/08/91 02/08/91 024 7/91 02/t7/91 "- / 91O/91 IN 91-XXJanuary xx, 1991 Inadequate Setpoint Determinations and EvaluationsMany of the findings identified during recent EDSFIs were related to inadequatesetpoint determinations. In order to properly determine an appropriateinstrument setpoint, all associated inaccuracies and tolerances must beaccounted for. Guidance for setpoint determinations is given in ANSI StandardS67.04-1988, 'Setpoints for Nuclear Safety-Related Instrumentation." Thisguidance is applicable not Just for instrumentation but is also applicable forcertain relays and other control oriented pieces of equipment.The setpoint problem is most prevalent for those instruments in which thelicensee has determined the setpoints as opposed to those setpoints determinedby the NSSS vendor. Those setpoints not contained in the plant technicalspecifications are also likely to be suspect. During recent EDSFIs, defi-ciencies in setpoints related to diesel day tank level indicators, diesel airstart compressor controllers and alarms, invertor low voltage shutdowncircuitry, degraded grid relays, and diesel overcurrent relays have beenidentified.In addition to the deficiencies identified in the setpoints themselves, the NRChas determined that licensees are not typically verifying that the magnitude ofsetpoint drift that was assumed in the original setpoint calculation is indeedcorrect. This verification can be performed by trending, i.e., by comparing"as found" calibration data to previous "as left" data. This is particularlyimportant for the degraded grid rely setpoints where very tight calibrationtolerance bands are often required and where very low drift values are oftenassumed. Failure to evaluate and account for instrument drifts has led to theoperation of equipment outside of acceptable limits which could compromise thesafety functions of the equipment.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contact thetechnical contact listed below or the appropriate NRR project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor Regulation


===Technical Contact:===
BKGrimes FRosa SNewberry 020 A' 02/djz1 02/ /91 02/ /91 02/ /91 02/ /91}}
Jeffrey B. Jacobson, NRR(301) 492-0996Attachment: List of Recently Issued NRC Information NoticesRPB:ADM C:OGCB:DOEA D:DOEATechEd CHBerlinger CERossi02/ /91 02/ /91 02/ /91RSIB: SC:RX RIS C:RSIB:DRIS D:DRIS C:SELB:DST C:SICB:DSTJBJac 6n:bt EVIm 'J>' WDLanning BKGrimes FRosa SNewberry020 A' 02/djz1 02/ /91 02/ /91 02/ /91 02/ /91  
}}


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

Revision as of 12:11, 31 August 2018

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 E
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 91-27 89-90, Supp. 1 91-26 91-25 91-24 91-23 Cracking in Feedwater System Piping Incorrect

Rotation of Positive Displacement

Pump Pressurizer

Safety Valve Lift Setpoint Shift Potential

Nonconservative

Errors in the Working Format Hansen-Roach

Cross-Section

Set Provided with The Keno and Scale Codes Commercial-Grade

Structural

Framing Components

Supplied As Nuclear Safety-Related

Equipment Recent Operating

Experience

Involving

Reactor Operation Without A Licensed Reactor Operator or Senior Reactor Operator Present in the Control Room Accidental

Radiation

Over-exposures

to Personnel

Due to Industrial

Radiography

Acces-sory Equipment

Malfunctions

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

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

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.

03/26/91 All Nuclear Regulatory

Commission (NRC) licens-ees authorized

to use 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 04/ fI9 OGC :DOEA: RR PCWen 04/ /91 CONCURRENCES

  • C/OGCB:DOEA:NRR*RPB:ADM
  • C/SICB:DST:NRR

CHBerlinger

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

  • SC/RSIB:DRIS:NRR*C/RSIB:DRIS:NRR

JBJacobson:bt

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

FRosa 03/18/91*D/DRIS:NRR

BKGrimes 02/27/91

  • - I IN 91-XX April xx, 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, Director Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical

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

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.In addition to identifying

deficiencies

in the setpoints

themselves, the NRC 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. Licensee can verify the magnitude

of instrument

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 calibra-tion tolerance

bands, and for which very low drift values are often assumed.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

Technical

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

EVImbro*02/08/91 C:RSIB:DRIS

WDLanning*

02/19/91 D:DRIS BKGrimes*02/27/91 C:SELB:DST

FRosa*03/18/91 C:SICB:DST

SNewberry*

03/18/91

-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.

In order to properly determine

an appropriate

instrument

setpoint, all associated

inaccuracies

and tolerances

must be accounted

for. Useful guidance for determining

setpoints

is provided by ISA 67.04-1982, "Setpoints

for Nuclear Safety-Related

Instrumentation

used in Nuclear Power Plants' which has been endorsed by Regulatory

Guide 1.105 Revision 2 -1986, "Instrument

Setpoints

for Safety Related Systems".

This guidance is applicable

not Just for instrumentation

but is also applicable

for certain relays and other control oriented pieces of equipment.

The setpoint problem has been identified

primarily

with those instruments

in which the licensee has determined

the setpoints

as opposed to those setpoints determined

by the NSSS vendor. Those setpoints

not contained

in the plant technical

specifications

are also likely to be suspect. During recent EDSFIs, deficiencies

in setpoints

related to diesel day tank level indicators, diesel air start compressor

controllers

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

relays have been identified.

In addition to the deficiencies

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 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

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 JBJacobson*:bt

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

Setpoint Determinations

and Evaluations

Many of the findings identified

during recent EDSFIs were related to inadequate

setpoint determinations.

In order to properly determine

an appropriate

instrument

setpoint, all associated

inaccuracies

and tolerances

must be accounted

for. Guidance for setpoint determinations

is given in ANSI Standard S67.04-1988, 'Setpoints

for Nuclear Safety-Related

Instrumentation." This guidance is applicable

not Just for instrumentation

but is also applicable

for certain relays and other control oriented pieces of equipment.

The setpoint problem is most prevalent

for those instruments

in which the licensee has determined

the setpoints

as opposed to those setpoints

determined

by the NSSS vendor. Those setpoints

not contained

in the plant technical specifications

are also likely to be suspect. During recent EDSFIs, defi-ciencies in setpoints

related to diesel day tank level indicators, diesel air start compressor

controllers

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

relays have been identified.

In addition to the deficiencies

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

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


Retrieved from "https://kanterella.com/w/index.php?title=Information_Notice_1991-29,_Deficiencies_Identifie_During_Electrical_Distribution_System_Functional_Inspections&oldid=1010608"