Information Notice 1988-73, Direction-Dependent Leak Characteristics of Containment Purge Valves
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C.
20555
September 8, 1988
NRC INFORMATION NOTICE NO. 88-73: DIRECTION-DEPENDENT LEAK CHARACTERISTICS
OF CONTAINMENT PURGE VALVES
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
This information notice is being provided to alert addressees to a potential
problem regarding unexpected direction-dependent leakage through containment
purge valves. It is expected that recipients will review the information for
applicability to their facilities and consider actions, as appropriate, to
avoid similar problems. However, suggestions contained in this information
notice do not constitute NRC requirements; therefore, no specific action or
written response is required.
Description of Circumstances
On May 18, 1988, during the performance of a Diablo Canyon Unit 1 containment
integrated leak rate test (ILRT), the licensee discovered that the 48-inch
purge system valves inside containment did not have adequate leakage integrity
(Licensee Event Report 50-275/87-25).
The licensee then successfully performed
a local leak rate test (LLRT) on the purge supply and exhaust penetrations by
pressurizing the volume between the inboard and outboard isolation valves. Al- though the LLRT was apparently a success, the valves inside containment were
pressurized from the direction opposite to the one required for them to perform
their safety function. The licensee determined earlier that this practice was
acceptable, based on information and test data supplied by the manufacturer
stating that pressure could be applied to the valve from either direction and
the valve would be leaktight.
The discrepancy between the ILRT and LLRT findings indicated that the LLRT
methodology of pressurizing the volume between the isolation valves did not
adequately confirm the operability of the inside valve.
The licensee's subsequent investigation found that the valves, Fisher Series
9200 butterfly valves, have a tapered seat that gives them a directionally
dependent leakage characteristic,
The valves inside containment are oriented
so that the discs face outward. Pressure from containment tends to unseat
the disc gaskets, whereas pressure from the opposite direction tends to seal
880010337
V
IN 88-73 September 8, 1988 the gaskets against the tapered valve seats.
The valves were purchased because
the manufacturer had specified that they could seal in either direction. The
licensee reversed the inboard purge valves in Unit 1 and made a commitment to
do the same for Unit 2.
Discussion:
Section III.C, "Type C tests," of Appendix J, "Primary Reactor Containment
Leakage Testing for Water-Cooled Power Reactors," to 10 CFR Part 50 states that
for containment isolation valve local leak rate testing, "pressure shall be ap- plied in the same-direction as that when the valve would be required to perform
its safety function, unless it can be determined that the results from the tests
for a pressure applied in a different direction will provide equivalent or more
conservative results." LLRT results could be misleading if the assumption that
an isolation valve does not have directionally-dependent leakage characteristics
is not true.
Direction-dependent leakage could be a characteristic of valves
other than the make and model used at Diablo Canyon.
No specific action or written response is required by this Information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
harlsE Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
James C. Pulsipher, NRR
(301) 492-0877 Attachment: List of Recently Issued NRC Information Notices
Attachment
September 8, 1988 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
88-72
88-71
Inadequacies In the Design
of dc Motor-Operated Valves
Possible Environmental
Effect of the Reentry
of COSMOS 1900 and
Request for Collection
of Licensee Radioactivity
Measurements Attributed
to That Event
Check Valve Inservice
Testing Program
Deficiencies
Movable Contact Finger
Binding in HFA Relays
Manufactured by General
Electric (GE)
9/2/88
9/1/88
8/29/88
8/19/88
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors, fuel
cycle licensees, and Priority 1 material licensees.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
88-70
88-69
88-48,
Supplement 1
Licensee Report of Defective
Refurbished Valves
8/24/88
All holders of OLs
or CPs for nuclear.
power reactors.
88-68
88-67 Setpoint Testing of Pres- surizer Safety Valves with
Filled Loop Seals Using
Hydraulic Assist Devices
PWR Auxiliary Feedwater Pump
Turbine Overspeed Trip
Failure
Industrial Radiography
Inspection and Enforcement
Inadvertent Drainages of
Spent Fuel Pools
8/22/88
8/22/88
8/22/88
8/18/88
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All NRC industrial
radiography licensees.
All holders of OLs
or CPs for nuclear
power reactors and
fuel storage facilities.
88-66
88-65 OL = Operating License
CP = Construction Permit
IN 88-73 September 8, 1988 the gaskets against the tapered valve seats. The valves were purchased because
the manufacturer had specified that they could seal in either direction.
The
licensee reversed the inboard purge valves in Unit 1 and made a commitment to
do the same for Unit 2.
Discussion:
Section III.C, "Type C tests," of Appendix J, "Primary Reactor Containment
Leakage Testing for Water-Cooled Power Reactors," to 10 CFR Part 50 states that
for containment isolation valve local leak rate testing, "pressure shall be ap- plied in the same direction as that when the valve would be required to perform
its safety function, unless it can be determined that the results from the tests
for a pressure applied in a different direction will provide equivalent or more
conservative results." LLRT results could be misleading if the assumption that
an isolation valve does not have directionally-dependent leakage characteristics
is not true.
Direction-dependent leakage could be a characteristic of valves
other than the make and model used at Diablo Canyon.
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the 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 Contact:
James C. Pulsipher, NRR
(301) 492-0877 Attachment:
List of Recently Issued NRC Information Notices
Transmitted by Region V in memo dated June 21, 1988
- SEE PREVIOUS CONCURRENCES
D
- C/OGCB:DOEA:NRR
- RPB:ARM
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CHBerlinger
TechEd
- SPIBDE/T8 R 08/22/88
07/28/88
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08/30/88
08/3/88
08/05/88
08/17/88
08/18/88
IN 88 August xx, 1988 to seal the gaskets against the tapered valve seats.
The valves were purchased
because the manufacturer had specified that they could seal in either direc- tion. The licensee reversed the inboard purge valves in Unit 1 and made a
commitment to do the same for Unit 2.
Discussion of Safety Significance:
Section III.C, "Type C tests," of Appendix J, "Primary Reactor Containment
Leakage Testing for Water-Cooled Power Reactors," to 10 CFR Part 50 states that
for containment isolation valve local leak rate testing, "pressure shall be
applied in the same direction as that when the valve would be required to
perform its safety function, unless it can be determined that the results from
the tests for a pressure applied in a different direction will provide equiva- lent or more conservative results." LLRT results could be misleading if the
assumption that an isolation valve does not have directionally-dependent
leakage characteristics is not true.
The NRC staff considers the Diablo Canyon experience relevant for all licensees
who use the purge capability during power operation. Direction-dependent leak- age could be a characteristic of valves other than the make and model used at
Diablo Canyon.
The corrective action taken at Diablo Canyon is appropriate
since operability of the purge valve under the dynamic conditions of a blowdown
remains satisfied.
No specific action or written response is required by this Information notice.
If you have any questions about this matter, please contact the 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 Contact:
James C. Pulsipher, NRR
(301) 492-0877 Attachments:
1. Figure 1:
Schematic Sealing Mechanism for Original
Orientation of Inside Purge Valve
2. List of Recently Issued NRC Information Notices
Transmitted by Region V in memo dated June 21, 1988
- SEE PREVIOUS CONCURRENCES
D/DOEA:NRR
C/OGCB:DOEA:NRR
- RPB:ARM
CERossi
CHBerlinger
TechEd
08/ /88
08/ /88
08/ /88 OGCB:DOEA NRR SPLB:DEST:NRR SPLB:DEST:NRR SAD/DEST:NRR
D/DEST:NRR
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j JPulsipher
JCraig
AThadani
LCShao
08/3&/88
08/ /88
07/28/88
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IN 88 August xx, 1988 to seal the gaskets against the tapered valve seats. The valves were purchased
because the manufacturer had specified that they could seal in either direc- tion.
The licensee reversed the inboard purge valves in Unit 1 and made a
commitment to do the same for Unit 2.
Discussion of Safety Significance:
Section III.C, 'Type C tests," of Appendix J, "Primary Reactor Containment
Leakage Testing for Water-Cooled Power Reactors," to 10 CFR Part 50 states that
for containment isolation valve local leak rate testing, "pressure shall be
applied in the same direction as that when the valve would be required to
perform its safety function, unless it can be determined that the results from
the tests for a pressure applied in a different direction will provide equiva- lent or more conservative results." LLRT results could be misleading if the
assumption that an isolation valve does not have directionally-dependent
leakage characteristics is not true.
The NRC staff considers the Diablo Canyon experience relevant for all licensees
who use the purge capability during power operation. Licensees who keep the
purge valves closed during power operation are not affected significantly as
long as the LLRT tests at least one valve in the proper direction. Direction- dependent leakage could be a characteristic of valves other than the make and
model used at Diablo Canyon. The corrective action taken at Diablo Canyon is
appropriate since operability of the purge valve under the dynamic conditions
of a blowdown remains satisfied.
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the 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 Contact:
James C. Pulsipher, NRR
(301) 492-0877 Attachments:
1. Figure 1:
Schematic Sealing Mechanism for Original
Orientation of Inside Purge Valve
2. List of Recently Issued NRC Information Notices
Transmitted by Region V in memo dated June 21, 1988
- SEE PREVIOUS CONCURRENCES
I I
D/DOEA:NRR
C/OGCB: DOE'A:NRR
- RPB:ARM
CERossi
CHBerlinger
TechEd
08/ /88
08/41/88
08/ /88 OGCB:DOEA:
SPLB:DEST:NRR SPLB:DEST:NRR SAD/DEST:NRR
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IN 88 August xx, 1988 to seal the gaskets against the tapered valve seats. The valves were purchased
because the manufacturer had specified that they could seal in either direc- tion. Neither the licensee nor the vendor realized that there could be direc- tion-dependent leakage. The licensee reversed the inboard purge valves in
Unit 1 and made a commitment to do the same for Unit 2.
Discussion of Safety Significance:
Section III.C, "Type C tests," of Appendix J., "Primary Reactor Containment
Leakage Testing for Water-Cooled Power Reactors," to 10 CFR Part 50 states that
for containment isolation valve local leak rate testing, "pressure shall be
applied in the same direction as that when the valve would be required to
perform its safety function, unless it can be determined that the results from
the tests for a pressure applied in a different direction will provide equiva- lent or more conservative results." LLRT results could be misleading if the
assumption that an isolation valve does not have directionally-dependent
leakage characteristics is not true.
The NRC staff considers the Diablo Canyon experience relevant for all licensees
who use the purge capability during power operation. Licensees who keep the
purge valves closed during power operation are not affected significantly as
long as the LLRT tests at least one valve in the proper direction. Direction- dependent leakage could be a characteristic of valves other than the make and
model used at Diablo Canyon. The corrective action taken at Diablo Canyon is
appropriate since operability of the purge valve under the dynamic conditions
of a blowdown remains satisfied.
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the 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 Contact:
James C. Pulsipher, NRR
(301) 492-0877 Attachments:
1. Figure 1:
Schematic Sealing Mechanism for Original
Orientation of Inside Purge Valve
2. List of Recently Issued NRC Information Notices
Transmitted by Region V in memo dated June 21, 1988
- SEE PREVIOUS CONCURRENCES
D/DOEA:NRR
C/OGCB:DOEA:NRR
- RPB:ARM
CERossi
CHBerlinger
TechEd
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08/ /88
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IN 88
July xx, 1988
,Page
2of 2 direction tends to seal the gasketfagainst the apered valve seat5 The valves
~ were purchased~w4th-the- speA4cat4on-that they could seal in e her direction.
AThert-was-no--ecognt- n-by-ethee' the licensee
-the vendor
)that
there could
.
!o
_§g^^tiwwee44cldependence-ef
lleakage.
The lcensee has'ieversed the inboard
purge valves in Unit 1 and Ma? made a commitment to do the same for Unit 2.
Discussion of Safety Significance:
(4 I'
1O-EfR 7Prt-5eO, Appendix J, Primary Reactor Containment Leakage Testing for
A Water-Cooled Power Reactors," in-Sectin- 4'-s---!Type-S-te
'states that
-
X hfor containment isolation valve local leak rate testing, "I
_pressure shall be
1
'
b
applied in the same direction as that when the valve would be required to
perform its safety function, unless it can be determined that the results from
the tests for a pressure applied in a different direction will provide equiva- lent or more conservative results.' LLRT results ayPbe misleading if the
assumption that an isolation valve does not have directionally-dependent
leakage characteristicsYoes -not/hpid-.V-
AJA
A~-
At'
1-J(t
TIfe~staff considers the Diablo Canyon experience to-haMverJe~vanee-t4eall
licensees who use the purge capability during power operation. Licensees who
/>9A
mainta+ir the purge valves closed during power operation are not affected as-¢---
j -Mgfincifintly4
_ong as the LLRT jests It least one valve in the proper
direction. T-dependeneof-eakage could be a characteristic of
valves other than the make and model used at Diablo Canyon. The corrective
'iW-
-actionat
Diablo Canyon is appropriate since operability of the purge valve
under the dynamic conditions of a blowdown remains satisfied.
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or theftegionaljXdministrator of the appropriate regional
office.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
James C. Pulsipher, NRR
(301) 492-0877 Attachments:
7
1. Figure 1:
Schematic of the Diablo Canyon Valves '
2. List of Recently Issued NRC Information Notices
OGCB:DOEA:NRR SPLB:DEST:NRR ePBARM
C/OGCB: DOEA:NRR
D/DOEA:NRR
CVHodge
JPulsipher
TechEd
CHBerlinger
CERossi
07/ /88
07/ /88
07/i4 /88
07/ /88
07/ /88