ML14191A974
| ML14191A974 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 02/23/1989 |
| From: | Belisle G, Tingen S, John Zeiler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML14191A973 | List: |
| References | |
| 50-261-89-01, 50-261-89-1, IEB-85-003, IEB-85-3, IEB-86-003, IEB-86-3, NUDOCS 8903240154 | |
| Download: ML14191A974 (16) | |
See also: IR 05000261/1989001
Text
UNITED STATES
o
NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTA ST., N.W.
ATLANTA, GEORGIA 30323
Report No.:
50-261/89-01
Licensee:
Carolina Power and Light Company
P. 0. Box 1551
Raleigh, NC 27602
Docket No.:
50-261
License No.:
Facility Name: H. B. Robinson
Inspection Conducted: January 9-13, 1989
Inspectors: Lb -- . )i
8e
Stepffen
in en
Date Signed
Dte Signed
Approved by:
6L
George A. Belisle, Chief
D te ig ed
Test Programs Section
Engineering Branch
Division of Reactor Safety
SUMMARY
Scope
This routine,
announced inspection was conducted in the areas of complex
surveillance, inservice testing, verification of containment integrity, local
leak rate testing, licensee action on NRC Bulletins 85-03 and 86-03,
and
licensee action on previous inspection findings.
Results
A strength was identified in the Licensee Bulletin 85-03 program that involved
a well documented and thorough design review that identified nine marginally
or undersized valve actuators, Paragraph 2.a.
In Paragraph 2.c, a weakness
was identified in the licensee internal response to Information Notice 86-05.
In Paragraph 3.b(2), a weakness in the inservice test program was identified that
involved review of stroke time results.
In Paragraph 3.b. (2), a violation was identified for failure to take corrective
action following detecting increased stroke times for cold shutdown valves.
9,O3240154 890307
AVICK 5o06
PNU
2
In paragraphs 2.c and 3.b.(2), the licensee made commitments in the areas of
main steam safety valve ring settings and cold shutdown valve stroke times that
would be accomplished prior to restart from the present refueling outages.
In the area of containment integrity, inspection findings indicated that the
licensee has developed and implemented a program of controls, procedures, and
test activities to ensure and maintain containment integrity.
Containment
related and post-LOCA mitigating systems and components reviewed were found to
be in a high state of availability.
0II
REPORT DETAILS
1. Persons Contacted
Licensee Employees
- J. Curley, Director, Regulatory Compliance
- R. Dayton, Project Engineer, Systems
- C. Dietz, Manager, Robinson Nuclear Project Department
S. Edwards, Senior Engineer, Technical Support
W. Farmer, Senior Engineer, Technical Support
- S. Griggs, Aide, Regulatory Compliance
- E. Harris, Jr., Director, Onsite Nuclear Safety
W. McCutcheon, ISI Technician
- R. Morgan, General. Manager
- M. Page, Acting Manager, Technical Support
- R. Powell, Engineering Supervisor, Technical Support
- S. Pruitt, Senior Specialist, ISI Coordinator
- D. Quick, Manager, Maintenance
- D. Sayre, Regulatory Compliance
- G Shartzer, Senior Engineer, Technical Support
- J Sheppard, Senior Engineer, Technical Support
- E. Shoemaker, Senior Engineer, Operations
Other licensee employees contacted during this inspection included
engineers, operators, technicians, and administrative personnel.
NRC Resident Inspector
- L. Garner, Senior Resident Inspector
- Attended exit interview
2. IE Bulletin and Information Notice Followup (25573) (92701) (97703)
a. IE Bulletin 85-03 Followup
(Closed) 85-BU-03, T2515/73S "Motor Operated Valve Common Mode
Failure During Plant Transients Due to Improper Switch Settings."'
The purpose of this Bulletin is to require licensees to develop and
implement a program to ensure that switch settings for high pressure
coolant injection and emergency feedwater system motor operated
valves (MOVs) subject to testing for operational readiness in
accordance with 10 CFR 50.55a(g)
are properly set, selected,
and
ma in
ta ined.
In order to evaluate the licensee'sBulletin 85-03 program, the
inspector held discussions with the appropriate licensee personnel
and reviewed the following:
Carolina Power & Light Company's
(CP&L)
letter, dated
January 22, 1988, Serial No. NLS-88-011.
Engineering Evaluation No. 87191, Justification for
Continued Operation for Steam Driven Auxiliary Feedwater
Pump Valves MS-V1-8A, B and C and MS-V2-14A, B and C.
Engineering Evaluation No. 87188,
Evaluation of Switch
Settings for Valves SI 870A and SI 870B Limitorque Motor
Actuators.
Engineering Evaluation No.
87190,
Evaluation of Switch
Settings for Valves V2-16A, B, and C Actuators.
Engineering Evaluation No. 87202, Standardization of Limit
Switch Settings on Valves Listed in Response to IE Bulletin
85-03.
(1)Bulletin 85-03 Action Item a required that the design basis for
the operation of each bulletin valve be reviewed and documented.
This item has been completed by the licensee.
Operation at 80
percent degraded voltage was a criterion for the design review
basis.
The documentation of the design review performed by the
licensee is extensive and thorough, and identified that 9 of the
11 bulletin valves had undersized or marginally sized actuators.
The nine valves with actuators scheduled to be replaced with
larger actuators are AFW-V2-16A,
B, and C, Motor Driven .
Auxiliary Feedwater Pump Discharge Isolation Valves, AFW-V2-14A,
B, and C, Steam Driven Auxiliary Feed Pump Discharge Isolation
Valves, and MS-V1-8A, B, and C, Steam Driven Auxiliary Feedwater
Pump Inlet Valves. These nine actuators will be replaced during
the
1990 refueling outage.
The licensee has. prepared
justifications for continued operation for these valves until
the actuators are replaced.
The inspector reviewed the
justifications for continued operation and considers them
acceptable.
(2)Bulletin 85-03 Action Item b required that correct switch
settings be reviewed and revised as necessary.
This item has
been completed by the licensee with the exception of sizing and
selecting actuator motor thermal overloads. The present thermal
overloads trip in 30 seconds.
The licensee is evaluating the
use of ten second trip overloads.
The ten second trip thermal
overloads will provide more protection to the actuator motor but
could result in spurious trips which have not been experienced
with the 30 second thermal overloads.
This is currently under
investigation.
(3)Bulletin 85-03 Action Item c required that switch settings be
changed as appropriate, based on the design review performed,
and each valve be demonstrated operable by testing the valve at
the maximum differential pressure it will see during the worst
3
case design accident pressure.
The licensee utilized motor
actuator characteristic (MAC)
diagnostic test equipment to
obtain the as-found and to verify the as-left switch settings.
During
the as-found diagnostic testing,
one deficiency
encountered was spring-pack gap. To perform diagnostic testing
with MAC equipment, the spring-pack cartridge cover is removed
and the MAC transducers are installed snugly against the
spring-pack, which eliminates spring-pack gap while testing.
After completion of MAC testing the spring-pack cartridge cover
is reinstalled. If the cartridge cover is the non-adjustable
type and a spring-pack gap does exist, then, the torque switch'
setting previously obtained from MAC testing has been altered.
To correct this situation the licensee has replaced the
nonadjustable spring-pack cartridge covers with adjustable
cartridge covers.
The adjustable cartridge cover can be
adjusted to fit snugly against the spring pack to eliminate
spring-pack gap.
During review of the licensee's bulletin program the inspector
noted that the differential pressure at which several valves
were tested was much less than the maximum design accident
differential pressures.
As previously discussed, the actuators
tested at lower pressures are scheduled to be replaced with
larger actuators. After replacement, the actuators and valves
are scheduled to be tested at maximum design accident
differential pressure.
The inspector discussed the need to
perform the differential pressure test at maximum design
differential pressure and acceptable alternatives for not doing
so. This area will be followed up during a future inspection.
(4)Bulletin 85-03 Action Item d required procedures to be prepared
or revised to ensure that .switch settings are maintained
throughout plant life and to include provisions to monitor valve
performance.
Licensee procedures recognize bulletin valve
revised switch settings, periodically require closed torque
switch settings to be verified, and reqjuire valves to be cycled
to verify operability.
The licensee is in the process of
expanding this program to establish post maintenance test
requirements and monitor valve performance.
Present licensee
post maintenance test requirements are to stroke time test the
valve following maintenance in accordance with ASME Section XI
code requirements.
Stroke timing alone is not an adequate test
following some types of maintenance; and additional testing in
the form of motor current measurement or actuator torque output
measurement should be performed.
Post maintenance testing and
provisions to monitor valve performance along with differential
pressure testing of replacement actuators is identified as
Inspector Followup Item 261/89-01-01.
4
(5)
As requested by Action Item e of Bulletin 85-03,
the licensee
identified the selected safety-related valves, the valves'
maximum differential pressures and the program to assure valve
operability in their letter dated July 30, 1986.
Review of this response indicated the need for additional
information which was requested in a NRC, Region II letter dated
August 18, 1987.
Review of the licensee's September 17,
1987,
response to this
request for additional information indicates that the licensee
selection of the applicable safey-related valves to be addressed
and the valves'
maximum differential pressures meets the
requirements of the bulletin and that the program to assure
valve operability requested by Action Item e of the bulletin is
now acceptable.
(6)Bulletin 85-03 Action Item f requires that a written report be
issued to the NRC on completion of the bulletin program.
The
licensee issued this report on January 22, 1988.
b. IE Bulletin 86-03 Followup
(Closed) 86-BU-03,
"Potential Failure of Multiple ECCS Pumps Due to
Single Failure of Air-operated Valve in Minimum Flow Recirculation
Line."
The purpose of this bulletin was to require licensees to
determine if a single valve failure due to loss of air or power in
the safety injection (SI)
pumps recirculation line would result in
dead heading and subsequent failure of the SI pumps.
The licensee
determined that this did apply to Robinson Nuclear Plant and
completed the corrective action during the present refueling outage.
Valves SI-856A and B are in series in the SI pump's common recircula
tion line to the Refueling Water Storage Tank (RWST).
The valves
would fail-closed on loss of air or power which would result in dead
heading all SI pumps.
Modification M-943 was recently completed. It
changed valves SI-856A and B from fail-closed to fail-open on loss of
air or power to the valves and added a hand wheel operator for manual
operation.
When switching SI.pump suction from the RWST to the
containment sump, the valves will be required to be manually shut.
C. IE Information Notice 86-05 and Supplement 1 Followup
This Information Notice alerts licensees that Main Steam Safety
Valves (MSSVs)
on pressurized water reactors may have never been
adequately tested to verify that the valves could pass full rated
steam flow.
Several examples were cited where utilities had to
adjust the MSSV ring settings from vendor original specifications to
new settings based on full flow testing performed on the licensee's
5
Robinson MSSVs are the same type of valves discussed in Information
Notice 86-05.
The valves are Crosby safety relief valves with
adjusting rings which determine the flow capacity and blowdown of the
valves.
The licensee's response to Information Notice 86-05 was to
follow the Westinghouse Owners Group (WOG) which is testing MSSVs in
order to establish MSSV ring settings where subsequent flowrates and
blowdowns were known.
Upon completion of the WOG MSSV testing, the
licensee was going to attempt to obtain the test results, and set
their MSSVs'
rings based on WOG testing.
The licensee was also
considering removing the MSSVs and performing full flow testing.
The licensee did not perform a safety analysis to determine if their
with present ring settings, provided flow to protect the
reactor plant during an accident.
Prior to restart following the
present refueling outage the licensee has committed to either adjust
MSSV ring settings to new settings specified by Crosby where adequate
flow testing has been performed to assure adequate flow and evaluate
the subsequent blowdown or perform a safety analysis to determine if
the reactor plant is protected with the present MSSV flow.
Information Notice 86-05 also discussed a utility where MSSV ring
settings were incorrectly set following maintenance due to procedure
inadequacy.
During the 1987 refueling outage Robinson discovered
that three of the 12 MSSVs had the following incorrect ring settings:
Valve No.
As-found Ring Settings
As-left Ring Setting
SV-3A
Nozzle Ring (-20)
Nozzle ring (-20)
Guide Ring (+125)
Guide Ring (+75)
SV-2B
Nozzle Ring (-15)
Nozzle Ring (-20)
Guide Ring (+75)
Guide Ring (+75)
SV-3B
Nozzle Ring (-15)
Nozzle Ring (-20)
Guide Ring (+75)
Guide Ring (+75)
In a CP&L inter-office correspondence letter dated September 1987,
the license recognized that the procedure, that addresses MSSV ring
settings,
CM-106,
required revision to ensure the as-found and
as-left ring settings were properly documented but revisions to
CM-106 have not been made. Procedure CM-106 provides instructions to
rebuild MSSVs,
but has not been performed since the 1987 refueling
outage. Prior to the next MSSV refurbishments, the licensee intends
to change CM-106 to document proper ring settings.
In this same
inter-office letter the licensee determined the three valves with
incorrect ring settings did not adversely affect relief capability.
Changing procedure CM-106 to properly document ring settings and
licensee action to adjust ring setting to obtain full rated flow is
identified as Inspector Follow-up Item 261/89-01-02, Revise Procedure
CM-106 to Provide for Adjustment of and Documentation of Ring
Settings.
III)
Within this area, no deviations or violations were identified.
3. Complex Surveillance and Inservice Testing (61701) (73756)
a. The inspector reviewed the MSSV and Pressurizer Safety Valve (PSV)
setpoint test surveillance program accomplished during the 1987
refueling outage.
Procedure No.
EST-028,
Revision 2, Main Steam
Safety Valve Testing, and EST-027,
Revision 7, Pressurizer Safety
Valve Testing, were reviewed by the inspector.
The setpoint
tolerance and test frequency for the PSVs are specified in Robinson
Technical Specifications (TS).
The MSSV setpoints and test frequency
are also specified in the TS; however, MSSV setpoint tolerance is
specified in Section III of the ASME code. MSSV and PSV test methods
are specified in ASME
Section XI,
1977 Edition, which invokes
ANSI/ASME-PTC 25.3-1976, Safety Relief Valves Performance Test Codes.
These requirements are included in Procedures EST-027 and EST-028.
(1) MSSV Testing
As specified by TS, the licensee tests all 12 MSSVs during each
refueling outage.
Robinson personnel setpoint tests MSSVs in
place with the main steam line at normal operating pressure and
temperature utilizing the Crosby pressure assist device. During
the 1987 refueling outage, all MSSVs were setpoint tested and
all as-left set points were within specified tolerances.
(2) PSV Set Point Testing
Robinson PSVs are installed on three insulated loop seals
attached to the top of the pressurizer. TS specify a setpoint
of 2485 psig with a plus 3 percent tolerance.
Robinson has
three spare PSVs.
Each refueling outage the PSVs are removed
from the pressurizer and the spares are installed. The removed
PSVs are then setpoint tested with water at ambient temperature
on a test bench.
The results of the setpoint testing of the
PSVs removed during the 1987 refueling are as follows:
Percent
As-left
Valve No.
As-found Set Point
Deviation
Set
from Set- Point
Point
RV-551A
2540
+2.2
2540
RV-551B
2600
+4.6
2520
RV-551C
2560
+3.0
2560
During the testing RV-551C seat leakage was found to be
excessive.
The seats were repaired and the valve retested.
Retest results were acceptable. PSV seat leakage does not appear
to be a significant problem at Robinson.
7
Within this area, no deviations or violations were identified.
b. Power Operated Valves Inservice Stroke Time Testing
Valve stroke time results obtained from Procedures OST-701, Inservice
Inspection Valve Test, and OST-703,
ISI Primary Side Valve Tests,
dating back to 1986 were used as a basis for this review.
The
requirements to stroke time valves are contained in TS, which invoke
Section XI of the ASME code.
The licensee is committed to the 1977
edition of Section XI.
The sections of Section XI inspected were
paragraphs IWV 3412 and 3413.
(1) Paragraph 3413(a) of Section XI requires that the limiting value
of full stroke time of each power operated valve shall be
specified by the owner. The limiting value of full stroke time
for numerous primary containment isolation valves contained in
OST-701 is 15 seconds; however, the actual measured stroke times
average from one to seven seconds.
(2) Paragraph IWV-3413(c) of Section XI states that if a stroke time
increase of 50 percent or more from the previous test for valves
with stroke times less than or equal to ten seconds is observed,
test frequency shall be increased to once each month until
corrective action is taken, at which time the original test
frequency shall be resumed. Paragraph.IWV-3413(c) also requires
that any abnormality or erratic action be reported.
During a
review of valve stroke times,
the inspector noted numerous
instances where valves with stroke times less than ten seconds
had a 50 percent or more increase in stroke time from the
previous test.
In the cases where stroke times increased 50
percent or more from the previous test, the valves would be
placed in a monthly surveillance status until stroke times
decreased to normal or a new base line developed.
In the cases
of abnormal stroke time decreases from the previous test, no
action was taken.
The action required to be taken following
increases and decreases in stroke times is judgmental; however,
the person making the judgement for subsequent actions has to be
knowledgeable of the valve and the system the valve is in, in
order to be able to determine if valve degradation or
malfunction is occurring.
At present, the licensee's inservice
test program does not have an individual knowledgeable of the
particular valve and system to provide input into stroke time
evaluations.
An inservice test individual is reviewing all
results; however, his primary function is in the area of tracking
results and ensuring that surveillance frequencies are performed.
This item was discussed with the licensee who indicated that
corrective action involving system engineers' review of stroke
times would be initiated.
Review of stroke time results by
system engineers will be verified by the Nuclear Regulatory
8
Commission during a subsequent inspection and is identified as
Inspector Followup Item 261/89-01-03.
Paragraph IWV-3412(a). of Section XI states that valves that
cannot be exercised during plant operation shall be specifically
identified by the owner and shall be full-stroke exercised
and
stroke time tested during cold shutdowns.
The inspector
reviewed the stroke time results of the primary containment
valve contained in OST-703, PCV-1716. The stroke times of valve
PCV-1716 are as follows:
Date
PCV-1716
Tested
(Seconds)
01/27/85
9.5
03/13/86
10.0
05/06/87
6.0
05/25/87
2.0
02/14/88
2.5
09/06/88
4.8
The stroke time on September 6, 1988 was a 92 percent increase
from the previous test on February 14,
1988.
No corrective
action nor evaluation was
performed for the PCV-1716
September 6, 1988,
increased stroke time prior to resuming
critical operations on September 19, 1988. The plant remained
operating until November 12, 1988, when it was shutdown for the
present refueling outage.
Valve PCV-1716 was not placed in
monthly surveillance during the September 19,
1988,
to
November 12, 1988, period.
As previously discussed, paragraph
IWV-3413(c) requires valves to be placed in monthly surveillance
until corrective action is taken when stroke times increase by
more than 50 percent.
Following the September 6, 1988, 92
percent increase in stroke time for valve PCV-1716 corrective
action was not taken nor was the valve placed on a monthly
surveillance schedule. Failure to comply with the requirements
of Paragraph IWV-3413(c),Section XI, is identified as Violation
261/89-01-04.
Several significant stroke time decreases occurred for valve
PCV-1716.
Present licensee practice is to record decrease in
stroke times but not evaluate why the decrease occurred.
A
stroke time decrease could be an indication of a valve failure
such as a disk separated from a valve stem for example, and
therefore, needs to be evaluated.
PCV-1716 was the only cold shutdown valve that the inspector
reviewed for stroke time performance.
As a result of this
finding, the licensee reviewed stroke times dating back to 1986
for all remaining cold shutdown valves
and identified
9
approximately 12 additional valves where stroke times exceeded
the 25 or 50 percent Section XI,
stroke time limits and
corrective action was not taken nor was frequency increased
to once each month.
The licensee committed to initiate
corrective action and to complete corrective action for the
cold shutdown valves that were identified to have the increased
stroke times prior to startup from the present refueling outage.
(3) The inspector reviewed copies of OST-701 that had been completed
back to 1986. The majority of the valves in OST-701 are primary
containment air operated valves with ASCO solenoid valves
directing the air to the valve.
The inspector also discussed
cycling of these valves with a senior shift supervisor.
The
review of OST-701 stroke time results indicate that only one
failure for a valve to operate had occurred since 1986.
This
failure was attributed to a valve lineup problem in the air
supply to the valve. Since operations personnel normally stroke
test valves, the inspector questioned the senior shift
supervisor if failures were occurring that were not documented,
if valves were being exercised prior to stroke timing, or if
tapping on ASCO solenoids ever occurred.
The senior shift
supervisor's reply was that these practices do not occur and, as
the OST-701 tests results indicate, the valves work well.
During this inspection, the inspector did not observe any ASCO
solenoid problems like those that have occurred at other sites.
4. Verification of Containment Integrity (61715)
The licensee's program designed to ensure and maintain containment
integrity was assessed by reviewing: (1) procedures and controls which
ensure that containment integrity is established, monitored, and main
tained, and (2) procedures and controls designed to mitigate contamination
releases in the event of loss of containment integrity following a
loss-of-coolant accident (LOCA).
Procedures were reviewed for technical
content adequacy, the proper extent of administrative control of activi
ties, and record keeping. Surveillance test records of tests performed in
accordance with plant TSs on containment related and post-LOCA mitigating
systems were reviewed to ascertain system and component availability
status.
System and component availability was evaluated to ensure that
containment integrity would be maintained in the event of severe
accidents.
The post-LOCA mitigating systems or components reviewed
included the following:
-
Containment isolation valve alignment, operability, and stroke time
-
Containment spray and iodine removal system
-
Containment fan coolers
10
Post accident containment venting system
-
Containment internal pressure limits
The operational readiness of post-LOCA mitigating systems was evaluated
based on the adequacy of the procedures, controls, and surveillance tests
conducted.
a. Documents Reviewed
-
Operating
Procedure
(OP)-923, Revision 8, "Containment
Integrity"
-
Operations Management Manual
(OMM)-008,
Revision 42,
"Minimum
Equipment List"
-
OP-921, Revision 10, "Containment Air Handling"
-
Operations Surveillance Test (OST)-701,
Revision 7, "Inservice
Inspection Valve Test", (Frequency: When Required)
-
OST-351,
Revision 7," Containment Spray System",
(Frequency:
Refueling)
-
Engineering Surveillance Test (EST)-006,
Revision 2, "Contain
ment Spray Nozzles", (Frequency: Five Years)
-
OST-902,
Revision 8, "Containment
Fan Coolers",
(Frequency:
Monthly)
-
OST-302,
Revision 24,
"Service Water System Component Test",
(Frequency: Quarterly)
-
OST-158,
Revision 7, "Safety Injection and Containment Spray
Flowpath Verification", (Frequency: Monthly)
b. Scope of Document and Record Review
The inspector reviewed the above surveillance procedures and related
documents either totally or in part to verify that applicable plant
TS requirements were met, that adequate information and instruction
were provided, and that adequate acceptance criteria and limits were
specified.
The following table describes the
TS
required
surveillance test records reviewed and gives the applicable TS which
requires the surveillance test.
Containment
Procedure
System
No.
Records Reviewed
T.S.
Isolation valve
OST-701
01/15/88 -
10/17/88
4.4.1.2.a
operability
11
Containment
OST-351
04/01/87 -
11/14/88
4.5.1.3
Spray System
EST-006
03/01/86
4.5.1.4
OST-158
03/20/88 -
10/24/88
4.5.2.2
Containment
OST-302
03/25/88 - 08/26/88
4.5.1.6
Fan Coolers
OST-902
04/06/88 - 11/03/88
4.5.1.6
Containment
OMM-008
12/88
3.6.2
Internal Pressure
Limits
c.
Procedure and Record Findings Summary
The procedures reviewed were technically accurate and in conformance
with plant TS.
Unacceptable conditions were not observed.
The surveillance test records
review did not identify any
discrepancies.
The inspectors verified that the surveillance tests
were performed at the required frequencies; that test results met
acceptance criteria or limits; and that appropriate sign-offs, test
reviews,
and test concurrences were performed.
These findings
indicated that TS required plant systems and components designed to
ensure containment integrity or mitigate post-LOCA contamination
releases are operable.
Within this area, no violations or deviations were identified.
5. Local Leak Rate Testing (61720)
a.
Inspection Scope
As part of the evaluation of containment integrity, the inspectors
reviewed procedures and controls established by the licensee to
verify local leak tightness of leakage barriers.
b. Documents Reviewed
-
Technical Support Management
Manual
(TMM)-005,
Revision 6,
"10 CFR 50, Appendix J Testing Program"
-
EST-004, Revision 8, "Isolation Seal Water System"
-
EST-009,
Revision 3, "Leak Rate Test of Containment Manometer
Line"
-
EST-010,
Revision 2, "Containment
Personnel Airlock Leakage
Test"
-
EST-059, Revision 3, "Local Leak Rate Test of Nitrogen Supply to
Accumulators Isolation Valves"
12
EST-060,
Revision 3, "Local
Leak Rate Test of N2 Supply to
Pressurizer Relief Tank Isolation Valves"
EST-061,
Revision 3, "Local Leak Rate Test of N2 Supply to
R. C. Drain Tank Isolation Valves"
-
EST-062,
Revision 1, "Local
Leak Rate Test of Containment
Instrument Air Header Isolation Valves"
-
EST-063,
Revision 5, "Leak Rate Test of Containment Firewater
Supply Isolation"
-
EST-064, Revision 0,."Containment Isolation Valve Local Leakage
Rate Survey"
The inspectors reviewed the documents listed above to determine
compliance with the regulatory requirements of Appendix J to
10 CFR 50, Technical Specifications, applicable industry standards,
and with station administrative guidelines. The inspectors also held
discussions with the licensee regarding test results documentation,
the repair and retesting following failed tests, and the relationship
of these items to the as-found and as-left containment conditions as
applied to the integrated leak rate test results.
The inspectors
also reviewed the completed as-found and as-left Type C local leak
rate test results for the past two years and the corrective
maintenance work performed on leaky valves in this time period.
c. Findings
In general, the leak rate test procedures were technically accurate
and in conformance with regulatory requirements.
However,
the
inspectors noted that ten containment isolation valves were being
leak rate tested by pressurizing in the non-accident direction.
10 CFR 50, Appendix 3,Section III.c.1 states that type C tests shall
be performed 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. The
following table lists information concerning the isolation valves in
question.
Containment
Valve
Valve Size
Ident.
and Type
2-N2 Supply to P. R. Tank
RC-550
0.75" Diaphragm
4-R.C. Drain Tank Vent
WD-1793
1" Diaphragm
35-Cont. Air Sample In
RMS-3
1" Diaphragm
36-Cont. Air Sample Out
RMS-1
1" Diaphragm
37-Cont. Purge Supply
V12-7
42" Butterfly
38-Cont. Purge Exhaust
V12-9
42" Butterfly
13
39-Cont. Service Air
SA-44
2" Diaphragm
40-Post Accident H2 Vent
Line
V12-18
3" Diaphragm
41-Cont. Press. Relief Line
V12-11
6" Butterfly
42-Cont. Vac. Relief Line
V12-13
6" Butterfly
The inspectors discussed this matter with the licensee and reviewed
valve drawings to determine if reverse testing'of the valves could be
considered equivalent or conservative.
Diaphragm valve drawings
indicated that their symmetrical design, with no specific inlet or
outlet side, provide bidirectional flow shutoff capability.
Therefore, for these valve types,
leak testing should provide
equivalent results from a pressure applied in either direction.
Purge valve drawings indicated a preferred valve installation which
is dependent on LOCA flow direction.
Based on the valve seat
arrangement depicted in the drawings, it appeared that direction
dependent leakage characteristics could exist for these valves. At
the exit meeting the licensee agreed to further review all the valve
designs and discuss with the valve manufacturers to determine if
reverse valve testing is considered equivalent or conservative.
By memorandum dated January 20,
1989, the licensee reported that
after further review and discussions with each valve vendor, the
valves in question were determined to have directionally independent
leakage characteristics at LOCA pressures.
According to the purge
valve manufacturer, the valve seal rings are designed to be resilient
enough for any pressure-induced deflections occuring under design
conditions.
Pressures sufficient to cause the valve disc to be
pushed away from the seal ring enough to unseat the valve would be
far in excess of LOCA pressures. For the remaining butterfly valves,
the vendors informed the licensee that the valves are designed to
provide equivalent leakage characteristics in both directions as long
as the pressure rating for the valves is not exceeded. The valve's
technical manual states that these 150 psi rated valves may be
installed with flow in either direction.
According to the vendor,
directional dependent leakage characteristics would not occur unless
pressures greater than design pressures were introduced.
The
licensee also reported that the diaphragm valve vendor confirmed that
there is no specified flow direction, no inlet or outlet side, and no
different leakage characteristics from pressures applied to one side
or the other. The inspectors were satisfied with these conclusions
and had no further concerns in this area.
Within this area, no violations or deviations were identified.
6. Exit Interview
The inspection scope and results were summarized on January 13, 1989, with
those persons indicated in paragraph 1.
The inspectors described the
areas inspected and discussed in detail the inspection results listed
14
below.
Proprietary information is not contained in this report.
Dissenting comments were not received from the licensee.
IFI 50-261/89-01-01,
Bulletin 85-03 post maintenance testing, provisions
to monitor valve performance,
and differential pressure testing of
replacement actuators, paragraph 2.a(4).
IFI 50-261/89-01-02, Changing procedure CM-106 to properly document ring
settings and licensee action to adjust ring settings to obtain full flow,
paragraph 2.c.
IFI 50-261/89-01-03, Engineering review of valve stroke time results,
paragraph 3.b(2).
Violation 261/89-01-04, Failure to increase to monthly surveillances or
take corrective action following increases in stroke times for cold
shutdown valves, paragraph 3.b(2).
In paragraphs 2.c and 3.b(2), the licensee made commitments in the areas
of main steam safety valve ring settings and cold shutdown valve stroke
times that would be accomplished prior to restart from the present
refueling outage.