Information Notice 1988-24, Failures of Air-Operated Valves Affecting Safety-Related Systems: Difference between revisions

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


COMMISSION
NUCLEAR REGULATORY COMMISSION


===OFFICE OF NUCLEAR REACTOR REGULATION===
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555 May 13, 1988 NRC INFORMATION


NOTICE NO. 88-24: FAILURES OF AIR-OPERATED
WASHINGTON, D.C. 20555 May 13, 1988 NRC INFORMATION NOTICE NO. 88-24:   FAILURES OF AIR-OPERATED VALVES


VALVES AFFECTING
AFFECTING SAFETY-RELATED SYSTEMS
 
SAFETY-RELATED
 
SYSTEMS


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


permits for nuclear power reactors.
reactors.


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


notice is being provided to alert addressees
problems with air-operated valves in safety-related systems. These problems


to potential problems with air-operated
result from overpressurizatlon failures of solenoid valves caused by the in- stallation of solenoid valves that may not operate against the supplied air


valves in safety-related
pressure. It Is expected that recipients will review the Information for ap- plicability to their facilities and consider actions, as appropriate, to avoid


systems. These problems result from overpressurizatlon
similar problems. However, suggestions contained in this information notice


failures of solenoid valves caused by the in-stallation
do not constitute NRC requirements; therefore, no specific action or written


of solenoid valves that may not operate against the supplied air pressure.
response is required.


It Is expected that recipients
==Description of Circumstances==
:
  Kewaunee: On February 8, 1988 the licensee, Wisconsin Public Service Corporation, notified the NRC in Licensee Event Report 50-305/87-12 of a potentially generic


will review the Information
problem. During a periodic inservice timing test required by technical speci- fications, the licensee observed that one of the redundant pressurizer relief


for ap-plicability
tank makeup isolation valves and one of the redundant reactor coolant drain


to their facilities
tank discharge header isolation valves failed to close on loss of electric


and consider actions, as appropriate, to avoid similar problems.
power to their respective 3-way solenoid valves. The isolation valves perform


However, suggestions
a containment Isolation function and since their source of actuator power, the


contained
instrument air system, is not a safety-related system, they are designed to


in this information
fail closed on loss of either air or electrical power.


notice do not constitute
For this application, when the solenoid valve is deenergized, its internal


NRC requirements;
spring moves the valve core so that the inlet port from the instrument air
therefore, no specific action or written response is required.Description


of Circumstances:
system is blocked. This action simultaneously opens a flow path connecting
Kewaunee:
On February 8, 1988 the licensee, Wisconsin


Public Service Corporation, notified the NRC in Licensee Event Report 50-305/87-12 of a potentially
the solenoid valve outlet and exhaust ports, permitting the air pressure on


generic problem. During a periodic inservice
the actuator diaphragm to decrease, and causing the isolation valve to close.


timing test required by technical
===C 8805090186 Z A4===


speci-fications, the licensee observed that one of the redundant
TN 88-24 May 13, 1988 Investigation revealed that the regulated inlet air pressure of 80 psi was


pressurizer
forcing the solenoid valve core away from the inlet port seat; as a result


relief tank makeup isolation
the flow path to the actuator diaphragm was being maintained. This happened


valves and one of the redundant
because the supply pressure exceeded the rating for the internal spring (70 psi).


reactor coolant drain tank discharge
This rating is called the design maximum operating pressure differential (MOPD).


header isolation
After the internal spring and core assembly were replaced in the failed sole- noid valves and the supply air pressure was reduced to 60 psi, the solenoid


valves failed to close on loss of electric power to their respective
valves and hence the containment isolation valves worked satisfactorily. The- licensee inspected ratings for other solenoid valves and did find instances


3-way solenoid valves. The isolation
where the solenoid valve had an MOPD less than the supplied air pressure.


valves perform a containment
In September 1987, the licensee had decided to replace a number of solenoid


Isolation
valves to upgrade their level of environmental qualification. For both the


function and since their source of actuator power, the instrument
failed solenoid valves discussed above, the licensee found that whereas the


air system, is not a safety-related
original valves had MOPD ratings greater than the supplied air pressure, the


system, they are designed to fail closed on loss of either air or electrical
replacement valves had MOPD ratings less than the supplied air pressure.


power.For this application, when the solenoid valve is deenergized, its internal spring moves the valve core so that the inlet port from the instrument
The licensee's investigation disclosed the following data:
      Original solenoid valves      ASCO Model No. LB83146- Catalog 26 (late 1960s vintage)
                                    General-purpose enclosure


air system is blocked. This action simultaneously
MOPD: 100 psi


opens a flow path connecting
Replacement solenoid valves  ASCO Model No. NP8314C13E


the solenoid valve outlet and exhaust ports, permitting
Catalog 30A (1980s vintage)
                                    Watertight and explosion-proof enclosure


the air pressure on the actuator diaphragm
MOPD: 70 psi'
According to the catalog, the letter "C" In the model number "indicates a maJor


to decrease, and causing the isolation
design change affecting spare parts kits, rebuild kits and colls." 'Apparently, one of the changes made by ASCO (the vendor) to the original Model No. 831413 valve, currently listed as a Model No. 8314C13 valve, involved the internal- spring and core assembly and resulted in a reduced MOPD.


valve to close.C 8805090186 Z A4 TN 88-24 May 13, 1988 Investigation
On seeing the difference in MOPD between the original and replacement solenoid


revealed that the regulated
valves, the design engineer assigned the task of upgrading the environmental


inlet air pressure of 80 psi was forcing the solenoid valve core away from the inlet port seat; as a result the flow path to the actuator diaphragm
qualification of these valves contacted the vendor for advice on which model


was being maintained.
was a direct nuclear grade replacement for the LB83146 model. The vendor :
recommended that model number NP8314C13E be used. The design engineer ques- tioned the vendor on the significance of the MOPD difference. The vendor


This happened because the supply pressure exceeded the rating for the internal spring (70 psi).This rating is called the design maximum operating
responded in writing essentially that if the supply pressure exceeded the MOPD


pressure differential (MOPD).After the internal spring and core assembly were replaced in the failed sole-noid valves and the supply air pressure was reduced to 60 psi, the solenoid valves and hence the containment
rating, the solenoid valve would not operate correctly (in the way described


isolation
above).


valves worked satisfactorily.
IN 88-24 May 13, 1988 The design engineer and engineering supervisor discussed this letter and con- cluded that if the solenoid valve were exposed to 100 psi instrument air pressure


The-licensee inspected
when deenergized, there would be some air leakage from the inlet to the outlet


ratings for other solenoid valves and did find instances where the solenoid valve had an MOPD less than the supplied air pressure.In September
ports, but some venting to atmosphere through the exhaust port would also occur.


1987, the licensee had decided to replace a number of solenoid valves to upgrade their level of environmental
This would pressurize the control valve diaphragm, but equilibrium would occur


qualification.
at a pressure below that required for control valve actuation. Their conclusion


For both the failed solenoid valves discussed
was heavily influenced by their belief that the original solenoid valves were


above, the licensee found that whereas the original valves had MOPD ratings greater than the supplied air pressure, the replacement
actually rated for 70 psi and had been operating successfully for approximately


valves had MOPD ratings less than the supplied air pressure.The licensee's
13 years.


investigation
Based on this interpretation, the design review package made available to the


disclosed
second level reviewer did not include a reference to this correspondence with


the following
the vendor. Thus, an independent assessment of the interpretation was not


data: Original solenoid valves ASCO Model No. LB83146-Catalog 26 (late 1960s vintage)General-purpose
performed.


enclosure MOPD: 100 psi Replacement
To see if other safety-related control valves and damper actuators could be


solenoid valves ASCO Model No. NP8314C13E
vulnerable to the same failure, the licensee inspected all the containment


Catalog 30A (1980s vintage)Watertight
Isolation solenoid valves and those solenoid valves included in the list of


and explosion-proof
systems and components that prevent or mitigate the consequences of postulated


enclosure MOPD: 70 psi'According
accidents. The licensee recorded the solenoid valve and air regulator name- plate data and the air regulator settings. For those valves with insufficient


to the catalog, the letter "C" In the model number "indicates
MOPD, the licensee determined the reason for the purchase and installation of


a maJor design change affecting
incorrect solenoid valves. They also reviewed the functional operability of


spare parts kits, rebuild kits and colls." 'Apparently, one of the changes made by ASCO (the vendor) to the original Model No. 831413 valve, currently
the instrument air regulators to provide assurance they will not fail high and


listed as a Model No. 8314C13 valve, involved the internal-spring and core assembly and resulted in a reduced MOPD.On seeing the difference
thus overpressurize the solenoid valves.


in MOPD between the original and replacement
Calvert Cliffs Unit 2: On April 14, 1988, the licensee, Baltimore Gas and


solenoid valves, the design engineer assigned the task of upgrading
Electric Company, notified the NRC in a 10 CFR 50.72 report that several safety


the environmental
systems were vulnerable to a single failure of the air supply pressure regu- lating system: the auxiliary feedwater system, the safety injection fill and


qualification
vent system, the containment isolation system, and the steam generator blowdown


of these valves contacted
isolation system. Investigation had shown that those air regulators located in


the vendor for advice on which model was a direct nuclear grade replacement
a harsh environment after a postulated accident can fail in a way that applies


for the LB83146 model. The vendor : recommended
high pressure to solenoid valves.    If such solenoid valves are not rated for


that model number NP8314C13E
sufficient MOPD, then the solenoid valves will affect the correct post accident


be used. The design engineer ques-tioned the vendor on the significance
alignment of the system valves they control. To correct this problem, the


of the MOPD difference.
licensee will expand emergency procedures to Include local operation of af- fected valves and will replace the affected solenoid valves with valves rated


The vendor responded
for higher MOPD.


in writing essentially
Discussion:
In many plants, the air supply systems for safety-related components are not


that if the supply pressure exceeded the MOPD rating, the solenoid valve would not operate correctly (in the way described above).
designed as safety-related systems. Hence, safety-related components that


IN 88-24 May 13, 1988 The design engineer and engineering
depend on the air system are designed to assume a fail safe condition on loss


supervisor
of air; however, the converse condition of air overpressurization may not always


discussed
be considered. Such a condition could render the affected safety-related com- ponents inoperable.


this letter and con-cluded that if the solenoid valve were exposed to 100 psi instrument
IN 88-24 May 13, 1988 Quality assurance requirements include procurement of materials, equipment, and


air pressure when deenergized, there would be some air leakage from the inlet to the outlet ports, but some venting to atmosphere
services (10 CFR 50.34 and Appendix B). The similarity of part numbers for


through the exhaust port would also occur.This would pressurize
components with different operating characteristics illustrates how a qualified


the control valve diaphragm, but equilibrium
component or system can be degraded if controls over the design and procurement


would occur at a pressure below that required for control valve actuation.
of replacement parts are not adequate.


===Their conclusion===
Other events in which air system failures have affected safety-related systems
was heavily influenced


by their belief that the original solenoid valves were actually rated for 70 psi and had been operating
are discussed in Information Notice 87-28, "Air System Problems at U.S. Light


successfully
Water Reactors," and Information Notice 87-28, Supplement 1, of the same title.


for approximately
The supplement notice transmitted copies of NUREG-1275, Vol. 2, "Operating


13 years.Based on this interpretation, the design review package made available
Experience Feedback Report - Air Systems Problems."'
No specific action or written response is required by this information notice.


to the second level reviewer did not include a reference
If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate


to this correspondence
regional office.


with the vendor. Thus, an independent
Charles E. Rossi, Director


assessment
Division of Operational Events Assessment


of the interpretation
Office of Nuclear Reactor Regulation
 
was not performed.
 
To see if other safety-related
 
control valves and damper actuators
 
could be vulnerable
 
to the same failure, the licensee inspected
 
all the containment
 
Isolation
 
solenoid valves and those solenoid valves included in the list of systems and components
 
that prevent or mitigate the consequences
 
of postulated
 
accidents.
 
The licensee recorded the solenoid valve and air regulator
 
name-plate data and the air regulator
 
settings.
 
===For those valves with insufficient===
MOPD, the licensee determined
 
the reason for the purchase and installation
 
of incorrect
 
solenoid valves. They also reviewed the functional
 
operability
 
of the instrument
 
air regulators
 
to provide assurance
 
they will not fail high and thus overpressurize
 
the solenoid valves.Calvert Cliffs Unit 2: On April 14, 1988, the licensee, Baltimore
 
Gas and Electric Company, notified the NRC in a 10 CFR 50.72 report that several safety systems were vulnerable
 
to a single failure of the air supply pressure regu-lating system: the auxiliary
 
feedwater
 
system, the safety injection
 
fill and vent system, the containment
 
isolation
 
system, and the steam generator
 
blowdown isolation
 
system. Investigation
 
had shown that those air regulators
 
located in a harsh environment
 
after a postulated
 
accident can fail in a way that applies high pressure to solenoid valves. If such solenoid valves are not rated for sufficient
 
MOPD, then the solenoid valves will affect the correct post accident alignment
 
of the system valves they control. To correct this problem, the licensee will expand emergency
 
procedures
 
to Include local operation
 
of af-fected valves and will replace the affected solenoid valves with valves rated for higher MOPD.Discussion:
In many plants, the air supply systems for safety-related
 
components
 
are not designed as safety-related
 
systems. Hence, safety-related
 
components
 
that depend on the air system are designed to assume a fail safe condition
 
on loss of air; however, the converse condition
 
of air overpressurization
 
may not always be considered.
 
Such a condition
 
could render the affected safety-related
 
com-ponents inoperable.
 
IN 88-24 May 13, 1988 Quality assurance
 
requirements
 
include procurement
 
of materials, equipment, and services (10 CFR 50.34 and Appendix B). The similarity
 
of part numbers for components
 
with different


operating
Technical Contacts:  Vern Hodge, NRR


characteristics
(301) 492-1169 I. Villalva, Region III


illustrates
(312) 790-5763 R. Nelson, Region III


how a qualified component
(414) 388-3156 Attachment: List of Recently Issued -NRC Information Notices     e
 
or system can be degraded if controls over the design and procurement
 
of replacement
 
parts are not adequate.Other events in which air system failures have affected safety-related
 
systems are discussed
 
in Information
 
Notice 87-28, "Air System Problems at U.S. Light Water Reactors," and Information
 
Notice 87-28, Supplement
 
1, of the same title.The supplement
 
notice transmitted
 
copies of NUREG-1275, Vol. 2, "Operating
 
Experience
 
Feedback Report -Air Systems Problems."'
No specific action or written response is required by this information
 
notice.If you have any questions
 
about this matter, please contact one of the techni-cal contacts listed below or the Regional Administrator
 
of the appropriate
 
regional office.Charles E. Rossi, Director Division of Operational
 
===Events Assessment===
Office of Nuclear Reactor Regulation
 
Technical
 
Contacts:
Vern Hodge, NRR (301) 492-1169 I. Villalva, Region III (312) 790-5763 R. Nelson, Region III (414) 388-3156 Attachment:  
List of Recently Issued -NRC Information
 
Notices e


Attachment
Attachment


IN 88-24 May 13, 1988 LIST OF RECENTLY ISSUED NRC INFORMATION
IN 88-24 May 13, 1988 LIST OF RECENTLY ISSUED                             I
 
NOTICES I Information
 
Date of Notice No. Subject Issuance Issued to 88-23 88-22 88-21 88-20 88-19 Potential


for Gas Binding of High-Pressure
NRC INFORMATION NOTICES


Safety Injection
Information                                    Date of


Pumps During a Loss-of-Coolant
Notice No.      Subject                        Issuance  Issued to


Accident.Disposal of Sludge from Onsite Sewage Treatment Facilities
88-23          Potential for Gas Binding      5/12/88  All holders of OLs


at Nuclear Power Stations Inadvertent
of High-Pressure Safety                  or CPs for PWRs.


Criticality
Injection Pumps During a


===Events at Oskarshamn===
Loss-of-Coolant Accident.
and at U.S. Nuclear Power Plants Unauthorized


Individuals
88-22            Disposal of Sludge from      .5/12/88  All holders of OLs


Manipulating
Onsite Sewage Treatment                  or CPs for nuclear


Controls and Performing
Facilities at Nuclear                  power reactors.


Control Room Actilvi ties Questionable
Power Stations


===Certification===
88-21            Inadvertent Criticality        5/9/88  All holders of OLs
of Class 1E Components


5/12/88.5/12/88 5/9/88 5/5/88 4/26/88 All holders of OLs or CPs for PWRs.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power, test and research reactors, and all licensed operators.
Events at Oskarshamn                    or CPs for nuclear


All holders of OLs or CPs for nuclear power reactors.88-18 Malfunction
and at U.S. Nuclear                      power reactors.


Radiography
Power Plants


of. Lockbox on Device 4/25/88 All NRC licensees authorized
88-20            Unauthorized Individuals      5/5/88   All holders of OLs


to manufacture, distribute, and/or operate radio-graphic exposure devices.88-17 Summary of Responses
Manipulating Controls and               or CPs for nuclear


to NRC Bulletin 87-01, "Thinning
Performing Control Room                  power, test and


of Pipe Walls in Nuclear Power Plants" 4/22/88 All holders of OLs or CPs for nuclear power reactors.OL = Operating
Actilvi ties                            research reactors, and all licensed


License CP = Construction
operators.


Permit A.
88-19          Questionable Certification    4/26/88  All holders of OLs


IN 88-24 May 13, 1988 Quality assurance
of Class 1E Components                  or CPs for nuclear


requirements
power reactors.


include procurement
88-18          Malfunction of. Lockbox on    4/25/88  All NRC licensees


of materials, equipment, and services (10 CFR 50.34 and Appendix B). The similarity
Radiography Device                      authorized to


of part numbers for components
manufacture, distribute, and/or operate radio- graphic exposure


with different
devices.


operating
88-17            Summary of Responses to NRC    4/22/88  All holders of OLs


characteristics
Bulletin 87-01, "Thinning of            or CPs for nuclear


illustrates
Pipe Walls in Nuclear Power              power reactors.


how a qualified component
Plants"
  OL = Operating License


or system can be degraded if controls over the design and procurement
CP = Construction Permit


of replacement
A.


parts are not adequate.Other events in which air system failures have affected safety-related
IN 88-24 May 13, 1988 Quality assurance requirements include procurement of materials, equipment, and


systems are discussed
services (10 CFR 50.34 and Appendix B). The similarity of part numbers for


in Information
components with different operating characteristics illustrates how a qualified


Notice 87-28, "Air System Problems at U.S. Light Water Reactors," and Information
component or system can be degraded if controls over the design and procurement


Notice 87-28, Supplement
of replacement parts are not adequate.


1, of the same title.The supplement
Other events in which air system failures have affected safety-related systems


notice transmitted
are discussed in Information Notice 87-28, "Air System Problems at U.S. Light


copies of NUREG-1275, Vol. 2, "Operating
Water Reactors," and Information Notice 87-28, Supplement 1, of the same title.


Experience
The supplement notice transmitted copies of NUREG-1275, Vol. 2, "Operating


Feedback Report -Air Systems Problems." No specific action or written response is required by this information
Experience Feedback Report - Air Systems Problems."
No specific action or written response is required by this information notice.


notice.If you have any questions
If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate


about this matter, please contact one of the techni-cal contacts listed below or the Regional Administrator
regional office.


of the appropriate
Charles E. Rossi, Director


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


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


Technical
Technical Contacts: Vern Hodge, NRR
 
Contacts: Vern Hodge, NRR (301) 492-1169 I. Villalva, Region III (312) 790-5763 R. Nelson, Region III (414) 388-3156 Attachment:
List of Recently Issued NRC Information
 
Notices*SEE PREVIOUS CONCURRENCES
 
/*C/OGCB:DOEA:NRR*PPMB:ARM
 
CHBerl inger TechEd 05/06/88 04/18/88*D/DSP:AEOD


*EAB:DOEA:NRR
(301) 492-1169 I. Villalva, Region III


TNovak RKarsch 04/22/88 4/27/88*OGCB:DOEA:NRR
(312) 790-5763 R. Nelson, Region III


CVHodge 04/04/88*RIII RNelson 03/28/88 LCShao 04/14/88 IN 88-XX May xx, 1988 Quality assurance
(414) 388-3156 Attachment:  List of Recently Issued NRC Information Notices


requirements
*SEE PREVIOUS CONCURRENCES                    /
                                                  *C/OGCB:DOEA:NRR*PPMB:ARM


include procurement
CHBerl inger  TechEd


of materials, equipment, and services (10 CFR 50.34 and Appendix B). The similarity
05/06/88      04/18/88
*OGCB:DOEA:NRR *RIII                              *D/DSP:AEOD    *EAB:DOEA:NRR


of part numbers for components
CVHodge        RNelson        LCShao              TNovak        RKarsch


with different
04/04/88      03/28/88      04/14/88            04/22/88      4/27/88


operating
IN 88-XX


characteristics
May xx, 1988 Quality assurance requirements include procurement of materials, equipment, and


illustrates
services (10 CFR 50.34 and Appendix B). The similarity of part numbers for


how a qualified component
components with different operating characteristics illustrates how a qualified


or system can be degraded if controls over the design and procurement
component or system can be degraded if controls over the design and procurement


of replacement
of replacement parts are not adequate.


parts are not adequate.No specific action or written response is required by this information
No specific action or written response is required by this information notice.


notice.If you have any questions
If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate


about this matter, please contact one of the techni-cal contacts listed below or the Regional Administrator
regional office.


of the appropriate
Charles E. Rossi, Director


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


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


Technical
Technical Contacts:  Vern Hodge, NRR


Contacts: Vern Hodge, NRR (301) 492-1169 I. Villalva, Region III (312) 790-5763 R. Nelson, Region III (414) 388-3156 Attachment:
(301) 492-1169 I. Villalva, Region III
List of Recently Issued Information


===Notices A draft of this information===
(312) 790-5763 R. Nelson, Region III
E. G. Greenman, Region III, notice was sent to C. E. Rossi, by memo dated March DOEA.17, 1988 from A-*SEE PREVIOUS CONCURRENCES


D/DOEA:NRR
(414) 388-3156 Attachment: List of Recently Issued Information Notices


CERossi 05/ /88*D/DEST:NRR
A draft of this information notice was sent by memo dated March 17, 1988 from


LCShao 04/14/88 C/OGCB: DOEA:NRR*PPMB:ARM
E. G. Greenman, Region III, to C. E. Rossi, DOEA.                        A-
*SEE PREVIOUS CONCURRENCES


CHBerlinger
D/DOEA:NRR          C/OGCB: DOEA:NRR*PPMB:ARM


TechEd 05/Do/88 04/18/88*D/DSP:AEOD
CERossi              CHBerlinger    TechEd


*EAB:DOEA:NRR
05/ /88              05/Do/88        04/18/88
*OGCB:DOEA:NRR *RIII          *D/DEST:NRR          *D/DSP:AEOD    *EAB:DOEA:NRR


TNovak RKarsch 04/22/88 4/27/88*OGCB:DOEA:NRR
CVHodge        RNelson        LCShao              TNovak         RKarsch


CVHodge 04/04/88*RIII RNelson 03/28/88 IN 88-XX April xx, 1988 of the instrument
04/04/88       03/28/88       04/14/88            04/22/88        4/27/88


air regulators
IN 88-XX


to document that they will not fail high and detrimentally
April xx, 1988 of the instrument air regulators to document that they will not fail high and


affect the performance
detrimentally affect the performance of the solenoid valves. Future corrective


of the solenoid valves. Future corrective
actions include the replacement of 27 of 130 solenoid valves inspected and the


actions include the replacement
establishment of a program for instrument air regulator settings.


of 27 of 130 solenoid valves inspected
Calvert Cliffs Unit 2:
On April 14, 1988, the licensee notified the NRC that several safety systems were


and the establishment
vulnerable to a single failure of the air supply pressure regulation systems:
the auxiliary feedwater system, the safety injection fill and vent system, the


of a program for instrument
containment isolation system, and the steam generator blowdown isolation system.


air regulator
Investigation had shown that those air regulators located in a harsh environment


settings.Calvert Cliffs Unit 2: On April 14, 1988, the licensee notified the NRC that several safety systems were vulnerable
after a postulated accident can fail in a way that applies high pressure to


to a single failure of the air supply pressure regulation
solenoid control valves.    If such control valves are not rated for sufficient


systems: the auxiliary
MOPD, then the control valves will affect the correct post accident alignment of


feedwater
the system valves they control. To correct this problem, the licensee will


system, the safety injection
expand emergency procedures to include local operation of affected valves and


fill and vent system, the containment
will replace the affected solenoid control valves with valves rated for higher MOPD.


isolation
Discussion:
In many plants, the air supply systems for safety-related components are not


system, and the steam generator
designed as safety-related systems. Hence, safety-related components that depend


blowdown isolation
on the air system are designed to assume a fail safe condition on loss of air;
however, the converse condition of air overpressurization may not always be


system.Investigation
considered. Such a condition could render the affected safety-related components


had shown that those air regulators
inoperable. The similarity of part numbers for components with different operating


located in a harsh environment
characteristics illustrates how a qualified component or system can be degraded


after a postulated
if controls over the design and procurement of replacement parts are not adequate.


accident can fail in a way that applies high pressure to solenoid control valves. If such control valves are not rated for sufficient
No specific action or written response is required by this information notice.


MOPD, then the control valves will affect the correct post accident alignment
If you have any questions about this matter, please contact a technical contact


of the system valves they control. To correct this problem, the licensee will expand emergency
listed below or the Regional Administrator of the appropriate regional office.


procedures
Charles E. Rossi, Director


to include local operation
Division of Operational Events Assessment


of affected valves and will replace the affected solenoid control valves with valves rated for higher MOPD.Discussion:
Office of Nuclear Reactor Regulation
In many plants, the air supply systems for safety-related
 
components


are not designed as safety-related
Technical Contacts:  Vern Hodge, NRR


systems. Hence, safety-related
(301) 492-1169 I. Villalva, Region III


components
(312) 790-5763 R. Nelson, Region III


that depend on the air system are designed to assume a fail safe condition
(414) 388-3156 Attachment: List of Recently Issued Information Notices


on loss of air;however, the converse condition
*SEE PREVIOUS PAGE FOR CONCURRENCE


of air overpressurization
D/DOEA:NRR    C/OGCB:DOEA:NRR      PPMB:ARM
 
may not always be considered.
 
Such a condition
 
could render the affected safety-related
 
components
 
inoperable.
 
The similarity
 
of part numbers for components
 
with different
 
operating characteristics
 
illustrates
 
how a qualified
 
component
 
or system can be degraded if controls over the design and procurement
 
of replacement
 
parts are not adequate.No specific action or written response is required by this information
 
notice.If you have any questions
 
about this matter, please contact a technical
 
contact listed below or the Regional Administrator
 
of the appropriate
 
regional office.Charles E. Rossi, Director Division of Operational
 
===Events Assessment===
Office of Nuclear Reactor Regulation


Technical
CERossi        CHBerlinger          TechEd


Contacts:  
04/ /88        04/ /88              04/11/881 OGCB:DOEA:NRR RIMI
Vern Hodge, NRR (301) 492-1169 I. Villalva, Region III (312) 790-5763 R. Nelson, Region III (414) 388-3156 Attachment:
List of Recently Issued Information


Notices*SEE PREVIOUS PAGE FOR CONCURRENCE
===CVHodge        RNelson 6,k===
                          Sw< D/DEST:NIT


D/DOEA:NRR
LCShao


C/OGCB:DOEA:NRR
0o


PPMB:ARM CERossi CHBerlinger
1A        TNovak


TechEd 04/ /88 04/ /88 04/11/881 OGCB:DOEA:NRR
,
                                                    D/DSP:AEOD phme      DOEA:EAB


RIM I Sw< D/DEST:NIT
RKarsch


0 o D/DSP:AEOD , phme DOEA:EAB CVHodge RNelson 6,k LCShao 1A TNovak RKarsch 04/oq/88 03/7 g/88 04/1l /88 04/72-/88  
04/oq/88       03/ 7g/88       04/1l /88           04/72-/88           4/tf /88'Zo'I}}
4/tf /88'Zo'I}}


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

Latest revision as of 03:50, 24 November 2019

Failures of Air-Operated Valves Affecting Safety-Related Systems
ML031150195
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date: 05/13/1988
From: Rossi C
Office of Nuclear Reactor Regulation
To:
References
IN-88-024, NUDOCS 8805090186
Download: ML031150195 (8)
v • d • e


NUCLA UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 May 13, 1988 NRC INFORMATION NOTICE NO. 88-24: FAILURES OF AIR-OPERATED VALVES

AFFECTING SAFETY-RELATED SYSTEMS

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is being provided to alert addressees to potential

problems with air-operated valves in safety-related systems. These problems

result from overpressurizatlon failures of solenoid valves caused by the in- stallation of solenoid valves that may not operate against the supplied air

pressure. It Is expected that recipients will review the Information for ap- plicability to their facilities and consider actions, as appropriate, to avoid

similar problems. However, suggestions contained in this information notice

do not constitute NRC requirements; therefore, no specific action or written

response is required.

Description of Circumstances

Kewaunee: On February 8, 1988 the licensee, Wisconsin Public Service Corporation, notified the NRC in Licensee Event Report 50-305/87-12 of a potentially generic

problem. During a periodic inservice timing test required by technical speci- fications, the licensee observed that one of the redundant pressurizer relief

tank makeup isolation valves and one of the redundant reactor coolant drain

tank discharge header isolation valves failed to close on loss of electric

power to their respective 3-way solenoid valves. The isolation valves perform

a containment Isolation function and since their source of actuator power, the

instrument air system, is not a safety-related system, they are designed to

fail closed on loss of either air or electrical power.

For this application, when the solenoid valve is deenergized, its internal

spring moves the valve core so that the inlet port from the instrument air

system is blocked. This action simultaneously opens a flow path connecting

the solenoid valve outlet and exhaust ports, permitting the air pressure on

the actuator diaphragm to decrease, and causing the isolation valve to close.

C 8805090186 Z A4

TN 88-24 May 13, 1988 Investigation revealed that the regulated inlet air pressure of 80 psi was

forcing the solenoid valve core away from the inlet port seat; as a result

the flow path to the actuator diaphragm was being maintained. This happened

because the supply pressure exceeded the rating for the internal spring (70 psi).

This rating is called the design maximum operating pressure differential (MOPD).

After the internal spring and core assembly were replaced in the failed sole- noid valves and the supply air pressure was reduced to 60 psi, the solenoid

valves and hence the containment isolation valves worked satisfactorily. The- licensee inspected ratings for other solenoid valves and did find instances

where the solenoid valve had an MOPD less than the supplied air pressure.

In September 1987, the licensee had decided to replace a number of solenoid

valves to upgrade their level of environmental qualification. For both the

failed solenoid valves discussed above, the licensee found that whereas the

original valves had MOPD ratings greater than the supplied air pressure, the

replacement valves had MOPD ratings less than the supplied air pressure.

The licensee's investigation disclosed the following data:

Original solenoid valves ASCO Model No. LB83146- Catalog 26 (late 1960s vintage)

General-purpose enclosure

MOPD: 100 psi

Replacement solenoid valves ASCO Model No. NP8314C13E

Catalog 30A (1980s vintage)

Watertight and explosion-proof enclosure

MOPD: 70 psi'

According to the catalog, the letter "C" In the model number "indicates a maJor

design change affecting spare parts kits, rebuild kits and colls." 'Apparently, one of the changes made by ASCO (the vendor) to the original Model No. 831413 valve, currently listed as a Model No. 8314C13 valve, involved the internal- spring and core assembly and resulted in a reduced MOPD.

On seeing the difference in MOPD between the original and replacement solenoid

valves, the design engineer assigned the task of upgrading the environmental

qualification of these valves contacted the vendor for advice on which model

was a direct nuclear grade replacement for the LB83146 model. The vendor :

recommended that model number NP8314C13E be used. The design engineer ques- tioned the vendor on the significance of the MOPD difference. The vendor

responded in writing essentially that if the supply pressure exceeded the MOPD

rating, the solenoid valve would not operate correctly (in the way described

above).

IN 88-24 May 13, 1988 The design engineer and engineering supervisor discussed this letter and con- cluded that if the solenoid valve were exposed to 100 psi instrument air pressure

when deenergized, there would be some air leakage from the inlet to the outlet

ports, but some venting to atmosphere through the exhaust port would also occur.

This would pressurize the control valve diaphragm, but equilibrium would occur

at a pressure below that required for control valve actuation. Their conclusion

was heavily influenced by their belief that the original solenoid valves were

actually rated for 70 psi and had been operating successfully for approximately

13 years.

Based on this interpretation, the design review package made available to the

second level reviewer did not include a reference to this correspondence with

the vendor. Thus, an independent assessment of the interpretation was not

performed.

To see if other safety-related control valves and damper actuators could be

vulnerable to the same failure, the licensee inspected all the containment

Isolation solenoid valves and those solenoid valves included in the list of

systems and components that prevent or mitigate the consequences of postulated

accidents. The licensee recorded the solenoid valve and air regulator name- plate data and the air regulator settings. For those valves with insufficient

MOPD, the licensee determined the reason for the purchase and installation of

incorrect solenoid valves. They also reviewed the functional operability of

the instrument air regulators to provide assurance they will not fail high and

thus overpressurize the solenoid valves.

Calvert Cliffs Unit 2: On April 14, 1988, the licensee, Baltimore Gas and

Electric Company, notified the NRC in a 10 CFR 50.72 report that several safety

systems were vulnerable to a single failure of the air supply pressure regu- lating system: the auxiliary feedwater system, the safety injection fill and

vent system, the containment isolation system, and the steam generator blowdown

isolation system. Investigation had shown that those air regulators located in

a harsh environment after a postulated accident can fail in a way that applies

high pressure to solenoid valves. If such solenoid valves are not rated for

sufficient MOPD, then the solenoid valves will affect the correct post accident

alignment of the system valves they control. To correct this problem, the

licensee will expand emergency procedures to Include local operation of af- fected valves and will replace the affected solenoid valves with valves rated

for higher MOPD.

Discussion:

In many plants, the air supply systems for safety-related components are not

designed as safety-related systems. Hence, safety-related components that

depend on the air system are designed to assume a fail safe condition on loss

of air; however, the converse condition of air overpressurization may not always

be considered. Such a condition could render the affected safety-related com- ponents inoperable.

IN 88-24 May 13, 1988 Quality assurance requirements include procurement of materials, equipment, and

services (10 CFR 50.34 and Appendix B). The similarity of part numbers for

components with different operating characteristics illustrates how a qualified

component or system can be degraded if controls over the design and procurement

of replacement parts are not adequate.

Other events in which air system failures have affected safety-related systems

are discussed in Information Notice 87-28, "Air System Problems at U.S. Light

Water Reactors," and Information Notice 87-28, Supplement 1, of the same title.

The supplement notice transmitted copies of NUREG-1275, Vol. 2, "Operating

Experience Feedback Report - Air Systems Problems."'

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Vern Hodge, NRR

(301) 492-1169 I. Villalva, Region III

(312) 790-5763 R. Nelson, Region III

(414) 388-3156 Attachment: List of Recently Issued -NRC Information Notices e

Attachment

IN 88-24 May 13, 1988 LIST OF RECENTLY ISSUED I

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

88-23 Potential for Gas Binding 5/12/88 All holders of OLs

of High-Pressure Safety or CPs for PWRs.

Injection Pumps During a

Loss-of-Coolant Accident.

88-22 Disposal of Sludge from .5/12/88 All holders of OLs

Onsite Sewage Treatment or CPs for nuclear

Facilities at Nuclear power reactors.

Power Stations

88-21 Inadvertent Criticality 5/9/88 All holders of OLs

Events at Oskarshamn or CPs for nuclear

and at U.S. Nuclear power reactors.

Power Plants

88-20 Unauthorized Individuals 5/5/88 All holders of OLs

Manipulating Controls and or CPs for nuclear

Performing Control Room power, test and

Actilvi ties research reactors, and all licensed

operators.

88-19 Questionable Certification 4/26/88 All holders of OLs

of Class 1E Components or CPs for nuclear

power reactors.

88-18 Malfunction of. Lockbox on 4/25/88 All NRC licensees

Radiography Device authorized to

manufacture, distribute, and/or operate radio- graphic exposure

devices.

88-17 Summary of Responses to NRC 4/22/88 All holders of OLs

Bulletin 87-01, "Thinning of or CPs for nuclear

Pipe Walls in Nuclear Power power reactors.

Plants"

OL = Operating License

CP = Construction Permit

A.

IN 88-24 May 13, 1988 Quality assurance requirements include procurement of materials, equipment, and

services (10 CFR 50.34 and Appendix B). The similarity of part numbers for

components with different operating characteristics illustrates how a qualified

component or system can be degraded if controls over the design and procurement

of replacement parts are not adequate.

Other events in which air system failures have affected safety-related systems

are discussed in Information Notice 87-28, "Air System Problems at U.S. Light

Water Reactors," and Information Notice 87-28, Supplement 1, of the same title.

The supplement notice transmitted copies of NUREG-1275, Vol. 2, "Operating

Experience Feedback Report - Air Systems Problems."

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Vern Hodge, NRR

(301) 492-1169 I. Villalva, Region III

(312) 790-5763 R. Nelson, Region III

(414) 388-3156 Attachment: List of Recently Issued NRC Information Notices

  • SEE PREVIOUS CONCURRENCES /
  • C/OGCB:DOEA:NRR*PPMB:ARM

CHBerl inger TechEd

05/06/88 04/18/88

  • OGCB:DOEA:NRR *RIII *D/DSP:AEOD *EAB:DOEA:NRR

CVHodge RNelson LCShao TNovak RKarsch

04/04/88 03/28/88 04/14/88 04/22/88 4/27/88

IN 88-XX

May xx, 1988 Quality assurance requirements include procurement of materials, equipment, and

services (10 CFR 50.34 and Appendix B). The similarity of part numbers for

components with different operating characteristics illustrates how a qualified

component or system can be degraded if controls over the design and procurement

of replacement parts are not adequate.

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

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Vern Hodge, NRR

(301) 492-1169 I. Villalva, Region III

(312) 790-5763 R. Nelson, Region III

(414) 388-3156 Attachment: List of Recently Issued Information Notices

A draft of this information notice was sent by memo dated March 17, 1988 from

E. G. Greenman, Region III, to C. E. Rossi, DOEA. A-

  • SEE PREVIOUS CONCURRENCES

D/DOEA:NRR C/OGCB: DOEA:NRR*PPMB:ARM

CERossi CHBerlinger TechEd

05/ /88 05/Do/88 04/18/88

  • OGCB:DOEA:NRR *RIII *D/DEST:NRR *D/DSP:AEOD *EAB:DOEA:NRR

CVHodge RNelson LCShao TNovak RKarsch

04/04/88 03/28/88 04/14/88 04/22/88 4/27/88

IN 88-XX

April xx, 1988 of the instrument air regulators to document that they will not fail high and

detrimentally affect the performance of the solenoid valves. Future corrective

actions include the replacement of 27 of 130 solenoid valves inspected and the

establishment of a program for instrument air regulator settings.

Calvert Cliffs Unit 2:

On April 14, 1988, the licensee notified the NRC that several safety systems were

vulnerable to a single failure of the air supply pressure regulation systems:

the auxiliary feedwater system, the safety injection fill and vent system, the

containment isolation system, and the steam generator blowdown isolation system.

Investigation had shown that those air regulators located in a harsh environment

after a postulated accident can fail in a way that applies high pressure to

solenoid control valves. If such control valves are not rated for sufficient

MOPD, then the control valves will affect the correct post accident alignment of

the system valves they control. To correct this problem, the licensee will

expand emergency procedures to include local operation of affected valves and

will replace the affected solenoid control valves with valves rated for higher MOPD.

Discussion:

In many plants, the air supply systems for safety-related components are not

designed as safety-related systems. Hence, safety-related components that depend

on the air system are designed to assume a fail safe condition on loss of air;

however, the converse condition of air overpressurization may not always be

considered. Such a condition could render the affected safety-related components

inoperable. The similarity of part numbers for components with different operating

characteristics illustrates how a qualified component or system can be degraded

if controls over the design and procurement of replacement parts are not adequate.

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

If you have any questions about this matter, please contact a technical contact

listed below or the Regional Administrator of the appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: Vern Hodge, NRR

(301) 492-1169 I. Villalva, Region III

(312) 790-5763 R. Nelson, Region III

(414) 388-3156 Attachment: List of Recently Issued Information Notices

  • SEE PREVIOUS PAGE FOR CONCURRENCE

D/DOEA:NRR C/OGCB:DOEA:NRR PPMB:ARM

CERossi CHBerlinger TechEd

04/ /88 04/ /88 04/11/881 OGCB:DOEA:NRR RIMI

CVHodge RNelson 6,k

Sw< D/DEST:NIT

LCShao

0o

1A TNovak

,

D/DSP:AEOD phme DOEA:EAB

RKarsch

04/oq/88 03/ 7g/88 04/1l /88 04/72-/88 4/tf /88'Zo'I


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