IR 05000458/1993004
| ML20036A993 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 04/27/1993 |
| From: | Westerman T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20036A987 | List: |
| References | |
| 50-458-93-04, 50-458-93-4, GL-89-10, NUDOCS 9305180044 | |
| Download: ML20036A993 (15) | |
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APPENDIX U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
i Inspection Report:
50-458/93-04 Operating License: NPF-47 Licensee: Gulf States Utilities
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P.O. Box 220 St. Francisville, Louisiana 70775
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Facility Name:
River Bend Station Inspection At: St. Francisville, Louisiana Inspection Conducted: March 29 through April 2, 1993
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Inspectors:
M. Runyan, Reactor Inspector, Engineering Section Division of Reactor Safety R. Vickrey, Reactor Inspector, Engineering Section
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Division of Reactor Safety Accompanied
By:
M. Holbrook, Consultant, EG&G Idaho i
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8"77-95 Approved:
T. Westerman, Chief, Engineering Section Date
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Division of Reactor Safety Inspection Summary Areas Inspected: Special, announced inspection of the implementation of the licensee's program to meet commitments to Generic Letter (GL) 89-10, " Safety-Related Motor-0perated Valve Testing and Surveillance," and followup of Part 1 inspection items.
'l Results:
The licensee's motor-operated valve program was greatly improved since
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the previous motor-operated valve inspection in December 1991, and appeared to be meeting the intent of Generic Letter 89-10 (Section 1).
The licensee committed to validate and revise, as necessary, potentially l
nonconservative assumptions utilized for valve factor, stem factor, and rate-of-loading in its motor-operated valve sizing calculations by
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July 1, 1993.
This item is considered unresolved since changes in the
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assumptions could result in some marginal valves beug declared j
inoperable (Section 1.1).
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t 9305180044 930511
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PDR ADOCK 05000458
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-2-A weakness was identified in the acceptance criteria used to demonstrate
motor-operated valve operability at degraded voltage (Section 1.1).
The licensee was in the process of evaluating changes made to the
vendor's recommended allowance for torque switch repeatability (Section 1.1).
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Test results indicated that valve factors were generally in excess of
the licensee's assumed value of 0.3; however, stem friction coefficients were generally far less than the assumed value of 0.15 (Section 1.2).
The licensee was in the process of changing assumed value factors from 0.3 to 0.5.
An unresolved item was identified concerning Valve ICCP*MOV138, which
exhibited an apparent valve factor of 1.8 and an unusual load sensitive behavior (Section 1.2).
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The licensee committed to discontinue a policy permitting the changing
of maximum expected differential pressures without engineering concurrence (Section 1.2).
l An extrapolation of test results from a differential pressure test had
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not been performed in a timely manner. As a result, a noncited violation was identified (Section 1.2).
The licensee was using a straight-line extrapolation method for
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differential pressure testing that had not been analytically justified (Section 1.2).
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The licensee was considering establishing a threshold percentage of the
maximum expected differential pressure below which test results would be
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considered not meaningful (Section 1.2).
l Acceptance criteria for static and dynamic tests did not include
evaluation of the diagnostic traces for abnormal valve or actuator i
behavior (Section 1.2).
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Some test data was outside the calibration range and not' capable of e
being used without additional analysis (Section 1.2).
Errors were identified in the use of the V0TES software (Section 1.2).
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The licensee intended to use static tests to periodically verify motor-i
operated valve capability (Section 1.3).
E The licensee indicated that the issues of pressure locking and thermal
binding would be further evaluated for normally open valves i
(Section 1.4).
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The licensee was in the process of developing a trending program
specifically for motor-operated valves subject to Generic Letter 89-10 (Section 1.5)-
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Summary of Inspection Findinas:
Unresolved Item 458/9304-01 was opened (Section 1.1).
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Inspection Followup Item 458/9304-02 was opened (Section 1.1).
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Inspection Followup Item 458/9304-03 was opened (Section 1.1).
- Inspection Followup Item 458/9304-04 was opened (Section 1.2).
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Unresolved Item 458/9304-05 was opened (Section 1.2).
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Noncited violation 458/9304-06 was opened (Section 1.2).
Inspection Followup Item 458/9304-07 was opened (Section 1.2).
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Inspection Followup Item 458/9304-08 was opened (Section 1.2).
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Inspection Followup Item 458/9304-09 was opened (Section 1.2).
- Inspection followup Item 458/9304-10 was opened (Section 1.2).
- Inspection followup Item 458/9304-11 was opened (Section 1.4).
- Inspection Followup Item 458/9124-01 was evaluated, but left open.
- Attachment Persons Contacted and Exit Meeting
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DETAILS
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GENERIC LETTER (GL) 89-10 " SAFETY-RELATED MOTOR-OPERATED VALVE [MOV)
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TESTING AND SURVEILLANCE" (2515/109)
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On June 28, 1989, the NRC issued GL 89-10, which requested licensees and construction permit holders to establish a program to ensure that switch settings for safety-related MOVs were selected, set, and maintained properly.
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Subsequently, four supplements to the GL have been issued and a fifth
submitted for comment. NRC inspections of licensee actions implementing i
commitments to GL 89-10 and its supplements have been conducted based on
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guidance provided in Temporary Instruction (TI) 2515/109, " Inspection
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Requirements for Generic Letter 89-10, Safety-Related Motor-Operated Valve Testing and Surveillance." TI 2515/109 is divided into Part 1, " Program Review," and Part 2, " Verification of Program Implementation." The TI 2515/109, Part 1 program review was conducted at River Bend December 9-13, 1991, and is documented in NRC Inspection Report 50-458/91-24. The inspection i
documented by this report was the initial inspection at River Bend under Part 2 of TI 2515/109 and, thus, was focused on verification of program implementation. Nevertheless, programmatic issues were addressed during this
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inspection in response to followup of findings in the Part 1 inspection and in the context of issues that developed in the course of the inspection.
i As an overall assessment of the licensee's MOV program, the inspectors i
concluded that substantial improvement had been realized since the Part 1 inspection in December 1991.
It was evident that the depth of thought and
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effort that had been placed into the program had been considerable. As a whole, the licensee's program appeared to be meeting the intent of GL 89-10.
1.1 MOV Sizino and Switch Settino
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The inspectors reviewed Procedure No. EDP-ME-26, " Stem Thrust / Torque
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Evaluation for Motor-Operated Valves," Revision 4, dated March 10, 1992, and the licensee's methodology for determination of thrust and torque requirements
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for the following valves:
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ICCP*M0V138 RPCCW Containment Isolation Valve
1E22*MOVF004 HPCS Injection Containment Isolation Valve IE12*M0VF064A Loop A RHR Pump Mini-Flow Valve IE12*MOVF027A Loop A LPCI Injection Isolation Valve IHVN*MOV22A Containment Unit Cooler Discharge Valve
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IG33*MOVF053 RWCU Containment Isolation Valve
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The licensee's gate valve thrust equation incorporated valve disc friction
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coefficients ranging from 0.30 to 0.50.
In light of industry experience and initial plant testing, the licensee has decided to use a more conservative
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0.50 valve factor for the remaining thrust settings to be implemented in the plant during the remaining outages. MOV load-sensitive behavior (also known
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-5-as " rate of loading" or "ROL") was addressed by adding a 5 percent margin for SB operators and a 10 percent margin for SMB operators. Thrust requirements were adjusted to account for diagnostic equipment inaccuracy and torque switch repeatability. Once dynamic test results were available for a given valve, the thrust requirements were revised to reflect the results of the dynamic test, including extrapolation to design-basis conditions (if required).
The inspectors noted that the licensee had made assumptions for valve factor, stem friction coefficient, and rate of loading (load-sensitive behavior) that had not been fully justified by way of a comparison to the results of the licensee's testing program. This was of concern in light of the fact that some of the assumptions were less conservative than average in the industry.
Specifically, the rate of loading assumption of 5 percent for SB actuators and 10 percent for SMB actuators was less than the more conservative value of approximately 15 percent; the stem friction coefficient assumption of 0.15 was less than the more accepted value of 0.20; and the 0.3 assumption for valve factor was well under the values of 0.4 to 0.6 indicated by many tests. The licensee informed the inspectors that the assumption for valve factor would be changed to 0.5 based on a preliminary review of test results.
In light of the probable existence of several marginal valves, it is possible that changes to
the assumed constants could result in some valves being declared inoperable.
This issue was identified as an unresolved item (458/9304-01). During the exit meeting, the licensee committed to complete the site-specific validation of the assumed constants by July 1,1993.
The inspectors noted that the licensee was establishing thrust windows that did not include consideration of MOV capability at degraded-voltage conditions. The rationale for this exclusion was that during the baseline static test, torque was being measured with the V0TES torque cell (VTC).
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Assuming that the torque switch will trip at the same torque level under any conditions (i.e., static or dynamic), and accounting for torque measurement
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inaccuracy and torque switch repeatability, this one time test was assumed to demonstrate that the actuator motor would not stall, if the corrected measured
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torque level at torque switch trip was less than the calculated torque output
capability of the motor-actuator at the assumed degraded voltage condition.
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The inspectors expressed a concern, based on the review of past testing, that l
torque was not being measured during subsequent testing and the thrust windows
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did not incorporate degraded voltage capabilities. The licensee stated that current testing has now included a nonintrusive type detector to monitor springpack displacement, which could be used as a comparison to the VIC
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measured displacements to detect any significant changes in the torque at
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torque switch trip. The inspectors found, from a review of current testing, that the licensee was monitoring springpack displacement, but had not established torque-related acceptance criteria. The licensee subsequently
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stated that acceptance criteria would be included in the post-test review l
process to ensure that the degraded voltage capability of the motor would not
be less than the torque necessary to trip the torque switch. This issue has
been identified as an inspection followup item (458/9304-02).
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-6-The licensee received Limitorque's Maintenance Update 92-2 on January 13, 1993, and issued tracking document SDDF3228201-007-011A as part of their
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vendor information review process. However, the review of this document was
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not completed at the time of the inspection.
Further, the changes for torque
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switch repeatability were not incorporated into the licensee's switch setting methodology. The licensee was considering the changes for torque switch repeatability as an open issue, but was also evaluating the use of in-plant t
data to support their current assumptions of 10 percent for outputs of less
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than 50 ft-lb and 5 percent for outputs over 50 ft-lb (irrespective of torque switch dial settings). The inspectors discussed the importance for performing an adequate number of valve strokes in order to develop a basis for alternate assumptions regarding torque switch repeatability. The licensee stated that the number of valve strokes would be considered. This issue was identified as an inspection followup item (458/9304-03).
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1.2 Eesian Basis Capability The inspectors reviewed Procedure No. EDP-ME-27, " Design Engineering Review of MOV Test Data," Revision 0, dated May 1, 1992, static test packages, and dynamic test packages for the following valves
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ICCP*MOV138 RPCCW Containment Isolation Valve IE22*M0VF004 HPCS Injection Containment Isolation Valve
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IE12*MOVF064A Loop A RHR Pump Mini-Flow Valve IE12*MOVF027A Loop A LPCI Injection Isolation Valve IHVN*MOV22A Containment Unit Cooler Discharge Valve IG33*MOVF053 RWCU Containment Isolation Valve The dynamic tests were conducted under the following conditions:
ICCP*MOV138 53 percent of MEDP IE22*MOVF004 108 percent of MEDP IE12*H0VF027A 100 percent of MEDP
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lHVN*MOV22A 51 percent of MEDP
Valves 1E12*MOVF064A and 1G33*MOV053 had been tested only under static conditions.
The inspectors reviewed the selected dynamic test data using the industry standard equation, the valve's orifice diameter, and the dynamic test conditions. This review indicated that valve factors in excess of 0.30 existed for the selected MOVs. The licensee had not drawn any general conclusions regarding their valve factor assumptions because the dynamic test review was not complete, however, the majority of stem friction coefficients observed thus far were less than 0.15.
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In response to the inspectors' request, licensee personnel performed a calculation that indicated that Valve ICCP*MOV138 had an apparent valve factor t
of approximately 1.8, based on the dynamic test results. As a comparison, Valve ICCP*MOV159, which is an identical valve in the system return line, had f
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an apparent valve factor of 0.47.
Valve ICCP*MOV138 also exhibited " negative i
MOV load-sensitive behavior," in that, thrust at control (torque) switch l
trip (CST) during the dynamic test was much higher then the thrust at CST under static test conditions. A 3-month time lag occurred between the performance of the static as-left test and the dynamic test; however, the
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torque switch dial setting had not been changed during this interim period.
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The valve was determined to be operable based on the thrust margin available i
at CST that was measured during the dynamic test, as compared to the extrapolated thrust requirement. The inspectors were concerned that the licensee's evaluation relied on the recurrence of this high level of negative
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load-sensitive behavior and on a stem friction coefficient that was much lower then the licensee's base assumption of 0.15.
During the dynamic testing of Valve ICCP*MOV138, the licensee recorded the
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downstream pressure during the test and determined that the assumption in the design-basis review regarding a zero downstream pressure for this closed loop system was overly conservative.
Field personnel revised the design-oasis differential pressure from 142 psid to approximately 109 psid without
engineering approval. The lower differential pressure was then used for
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extrapolation purposes.
This modification was considered acceptable at that
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time because the system test lineup was the same as the original design-basis
scenario. However, the inspectors were concerned that informal modifications
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to the design-basis calculations could result in non-conservative MOV switch
settings. The licensee has agreed that engineering will be responsible for all future changes to the original design-basis calculations, and that the
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original design-basis conditions will be used for initial extrapolations
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performed to determine valve operability. This policy change was identified i
as an inspection followup item (458/9304-04). Further, because of the
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questionable nature of the static / dynamic test results, the licensee has
committed to develop a corrective action plan for resolving the valve factor
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and load-sensitive behavior issues for Valve ICCP*MOV138. This issue was
identified as an unresolved item (458/9304-05).
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t During review of the test package documenting the differential pressure test
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of Valve IHVN*MOV22A, the inspectors noted that the step in the acceptance i
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criteria to extrapolate data from the test conditions to the design basis condition had been initially marked (on April 9,1992) "not applicable." The
maximum expected differential pressure calculated for this valve was 100 pounds per square inch differential (psid), whereas the test had been
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performed at approximately 54 psid. A licensee review of this package was
performed on March 25, 1993, at which time it was recognized the evaluation of acceptance criteria had failed to extrapolate the results in accordance with
test requirements.
In addition, the acceptance criteria evaluation had been independently reviewed and accepted. The linear extrapolation of thrust
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indicated that Valve IHVN*M0V22A required 4292 pounds thrust at 100 psid as
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compared to 7266 pounds thrust measured at control switch trip. Therefore, the valve was still considered operable. The licensee stated that all of the i
differential pressure packages had been recently reviewed; therefore, any
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other similar cases would have been identified. The failure to properly
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Where testing could not be conducted at design-basis conditions, the licensee utilized a straight-line extrapolation of the thrust to overcome differential pressure using the ratio of design-basis differential pressure to the test differential pressure.
The licensee considered a straight-line extrapolation from 80 percent (or higher) to 100 percent of design-basis conditions to be
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acceptable for determining design-basis requirements. However, the licensee
had not performed multi-point differential pressure testing nor developed l
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other methods to justify the long-term acceptability of its extrapolation method.
Therefore, the inspectors considered tests of 80 percent to 100 percent of design-basis conditions to be the first stage of a two-stage approach where the valves have been set up using the best available data, as discussed in GL 89-10.
The licensee is expected to justify its method of extrapolation by their comitment date for the completion of the GL 89-10
program.
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During discussions with the inspectors, the licensee stated that a policy was
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under consideration to establish a certain percentage of the maximum expected
differential pressure (MEDP) below which a test at differential pressure would be considered "not meaningful." The implementation of this policy would
result in the cancellation of differential pressure testing for those M0Vs
that could not be tested at differential pressures above the established l
benchmark. The licensee recognized that this policy change, if implemented,
would constitute a change in their comitment to GL 89-10 and its supplements
to test at the highest achievable conditions. The inspectors stated that the
NRC would be receptive to this concept if it could be adequately justified.
i The licensee indicated that 20 percent of the MEDP was being tentatively ('
considered as the cutoff point. The inspectors noted that Valve IG33*MOV53A was on a list of valves that would be tested only under static conditions even f
though it would appear that this valve could be tested at greater than
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20 percent of its MEDP. The issue of meaningful testirn and the testing of Valve IG33*MOV53A was identified as an inspection followap item (458/9304-07).
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The licensee's static and dynamic test acceptance criteria did not include a l
requirement to inspect diagnostic traces to ensure that no anomalies or i
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abnormalities are present. However, the licensee committed to address this weakness in their program. This issue was identified as an inspector followup i
item (458/9304-08).
During review of diagnostic traces, the inspectors noted that some of the peak thrust measurements were outside the V0TES best-fit straight-line (BFSL)
calibration range.
Liberty Technology has not identified a method to account i
for the uncertainties associated with measurements that have been extrapolated
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using a BFSL calibration. The licensee agreed to review all diagnostic traces
and work with Liberty Technology to resolve any extrapolations where a BFSL calibration may have been used. This issue was identified as an inspector
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followup item (458/9304-09).
During review of the dynamic closing stroke traces for Valve ICCP*MOV138, the inspectors noted that the diagnostic software mark for Point Cll,
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identification of hard seat contact, was positioned earlier in the trace than the mark for Point CIO, identification of flow isolation. Additionally, for the dynamic test of Valve IHVN*MOV22A, the licensee had marked the VOTES trace incorrectly.
Point CIO, flow cutoff, had been marked prior to Point C5, running load near the end of the stroke.
In neither case did the marking anomalies affect the operability status of the valves. The licensee acknowledged that these were technician errors and stated that additional training would be conducted on the proper methodology of using the V0TES software. This will be tracked as an inspection followup item (458/9304-10).
1.3 Periodic Verification The licensee stated that it planned to use static tests of MOVs in an effort to demonstrate conti3ued capability to perform under design basis conditions.
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The licensee had not @ veloped justification for the use of static tests to demonstrate design-basis capability. However, justification will eventually
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be required for whatever method the licensee selects to demonstrate continued MOV operability on a periodic basis.
1.4 Pressure lockino l
The Office for Analysis and Evaluation of Operational Data (AEOD) completed a l
study of pressure locking and thermal binding of gate valves. AE0D concluded
in its report that licensees have not taken sufficient action to provide
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assurance that pressure locking or thermal binding will not prevent a gate
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t valve from performing its safety function. The NRC regulations require that licensees design safety-related systems to provide assurance that those systems can perform their safety functions.
In GL 89-10, the staff requested licensees to review the design bases of their safety-related MOVs.
The inspectors reviewed the licensee's evaluations of the potential for pressure locking and thermal binding of gate valves as part of their design basis review. Where such a potential was identified, the inspectors reviewed
the licensee's actions taken to prevent pressure locking and thermal binding.
The licensee identified eight valves that were potentially susceptible to pressure locking or thermal binding. Modifications to these valves were completed via MR's 87-0101 and 88-0145. Operations and maintenance training relating to diagnosing the gate valve pressure locking and thermal binding
failure mechanism and the action necessary to recover, were conducted by the training department.
Although the licensee had addressed normally closed valves, the inspectors
questioned whether they had considered pressure locking to be credible for
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-10-l certain normally open valves. Although Engineering Evaluation Assistance
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Request (EEAR) 88-R0142 indicated that the licensee had conducted a review to
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determine if any additional valves could fail during test conditions, the l
licensee was unable to provide detailed documentation of the scope of that review. The licensee was unable to provide documentation that normally open valves had been sufficiently evaluated in the event of maintenance,
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surveillance, or testing activities which might preclude the restoration of these valves for a longer than expected time. Additionally, the inspectors questioned whether rapid depressurization effects had been evaluated. The
licensee informed the inspectors that further evaluation of these normally open valves and rapid depressurization would be necessary to establish whether
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controls were sufficient. The licensee's further evaluation of normally open valves and rapid depressurization will be reviewed during a future inspection and has been identified as an inspection followup item (50-458/9304-11).
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1.5 MOV Failures. Corrective Actions. and Trendina In GL 89-10, the NRC requested that the licensees analyze or justify each MOV i
failure and corrective action. The documentation should include the results
and history of each as-found deteriorated condition, malfunction, test,
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inspection, analysis, repair, or alteration. All documentation should be retained and reported in accordance with plant requirements.
It was also
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suggested that the material be periodically examined as part of the monitoring
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and feedback effort to establish trends of MOV operability. These trends l
could provide the basis for a licensee revision of the testing frequency established to verify MOV capability on a periodic basis. The GL indicated that a well-structured and component-oriented system would be necessary to track, capture, and share equipment history data.
During the GL 89-10 Part 1 inspection, the licensee was using existing plant i
programs to identify and correct M0V failures. Furthermore, the licensee was in the process of developing a trending program for MOVs. During this
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inspection the inspectors reviewed the licensee's progress in developing a
trending system specifically for the GL 89-10 MOVs. The licensee had issued i
Procedure PEP-0059, " Motor-0perated Valve Trending," Revision 0, on March 25, l
1993. This procedure established a methodology to evaluate MOV performance
and to define the methodology and responsibilities for control and maintenance of the MOV trend database.
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i 1.6 Followuo of Weaknesses and Observctions Enumerated in the Part 1 Report
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i In NRC Inspection Report 50-458/91-27, several weaknesses were identified in
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the licensee's program for implementing commitments to GL 89-10. The licensee was required to provide a written response addressing each of the items identified as a response item.
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Response Item I The licensee had initially used a stem friction coefficient of 0.15 and a valve factor of 0.30 in many valve calculations. These values have been shown to be nonconservative in many +plications based on current industry data.
The licensee was requested to submit a plan of action to validate or revise as necessary the 0.15 stem friction coefficient and 0.30 valve factor based on in-situ testing results. The submittal was to include information gained from recent testing results.
The licensee responded by developing Engineering Department
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Procedure (EDP) ME-27, " Design Engineering Review of MOV Test Data,"
Revision 0, to provide a methodology to feed back information from diagnostic testing and maintenance to confirm the validity of the origir.al design assumptions used and revise them as necessary. Two of the parameters to be evaluated in EDP ME-27 were the stem friction coefficient and the valve factor. The procedure was to become an ongoing process comparing current test data with calculation coefficients to verify previous assumptions. The procedure was to include provisions for review of similar valves and an overall review periodically of the program assumptions. Additionally, t~ne licensee's response included information gained from recent testing results which showed that when using the newly acquired V0TES test system, the licensee had determined that the design basis review methodology was very conservative.
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The inspectors reviewed EDP ME-27. This procedure provides guidance for evaluating status and flow (dp) test results, including validation of stem factors, valve factor, and coefficients of friction. The inspectors concluded that this procedure provided a methodology to feed back information from diagnostic testing and maintenance to confirm the validity of the original design assumption used and to revise them as necessary. As discussed in Section 1.1, the licensee has decided to change valve factor assumptions from 0.3 ta 0.5.
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Response Item 2 The inspectors' review of several sizing and switch setting calculations
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revealed that some valves may be undersized and require additional corrective actions. The licensee was requested to review all of their currently completed calculations to determine those MOVs that were marginally sized.
This subset of the valves should then be assessed from an operability
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standpoint. The licensee's submittal was to include the results of the review of the current calculations and plans to include that effort as a programmatic <
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step for future calculations.
The licensee responded that they had reviewed all GL 89-10 calculations issued through March 19, 1992, to identify potentially marginally sized actuators.
This review concluded that all MOV actuators were adequately sized to perform their design function under calculated differential pressures.
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the licensee revised EDP ME-26, " Stem Thrust / Torque Evaluation for
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Motor-0perated Valves," Revision 4, to incorporate checks for design margin i
and for testing margin after application of test equipment and other application error factors.
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The inspectors revieved EDP-ME-26. The inspectors concluded that this procedure had been appropriately revised to incorporate evaluation of design
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margin and test margin after application of test equipment and other application error factors. The licensee had completed review of all their
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currently completed calculations to identify potentially marginally sized i
actuators. The review concluded that all MOV actuators were adequately sized.
Response Item 3 The licensee's program description and memoranda stated that MOVs could be grouped for the purposes of reducing the number of required full-flow tests.
This position was not consistent with the licensee's comitment in response to GL 89-10 to flow test MOVs where practicable. The licensee indicated during the inspection that it intended to comply with their original comitment. The licensee was requested to submit revised program documentation confirming
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their original comitment.
The licensee responded by revising Section 6.4.5 of the program description to
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restate their original position. Also added, was a requirement to justify
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exceptions to that position and the requirement to notify the NRC of any changes to their current position.
The inspectors reviewed Section 6.4.5 of the licensee's program description,
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which now requires full-flow tests where possible.
In cases where in-situ full-flow and differential pressure testing cannot be accomplished, testing will be performed at the maximum flow and differential pressure conditions achievable using permanent plant equipment. The inspectors concluded that the
licensee's revised program description confirmed their original comitment.
Response Item 4 The licensee's initial testing schedule indicated that very few MOVs would be tested at greater than static conditions. The licensee was requested to submit a list of all MOVs (114 total) to be tested during refueling outage RF-4 showing for each: valve size, valve type (globe, gate, butterfly),
whether it was anticipated that the valve would be tested under flow and differential pressure conditions, and, if so, the approximate percentage of maximum expected differential pressure and flow that would be attained during the test.
The licensee responded by reviewing the initial list of MOVs to be teted in Refueling Outage RF-4 to identify additior.al valves that could be flow tested and provided the NRC with a revised testing schedule.
The inspectors reviewed the licensee's list of 114 MOVs scheduled for testing during Refueling Outage RF-4.
Of this number, 73 valves were scheduled for
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-13-dynamic testing as well as a static baseline test and 41 valves were scheduled for static tests alone. The inspectors concluded that the licensee was making reasonable efforts at testing MOVs at greater than static conditions.
I Response Item 5 The licensee did not have a clearly-defined methodology to feedback information from diagnostic testing and maintenance and failure events to confirm the validity of the original design assumptions. The licensee was
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requested to submit a plan to establish that feedback process.
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The licensee responded by preparing EDP ME-27 to specifically address this
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item.
I The inspectors reviewed EDP ME-27, and concluded that this procedure provides a method to feedback information from diagnostic testing and maintenance and failure events into design calculations to verify the validity of the design
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assumptions.
Response item 6 For Supplement 3 valves, the licensee was awaiting information from the valve
vendor, Velan, to confirm that the valves could withstand the structural
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stresses expected when closing during a design basis event. The licensee was requested to submit the information supplied by the vendor.
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The inspectors reviewed the letter submitted by the licensee from Velan, dated March 9,1992, and verified that it concluded that these valves were capable
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of withstanding the full output of the actuator on a one-time basis.
Re:nonse Item 7
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The licensee was in the process of establishing a new system for the design control of MOV switch setpoints. The licensee was requested to submit a description of their proposed method of controlling switch setpoints.
The licensee responded that control of torque switch setting was provided through a list of minimum and maximum values stated in Maintenance Procedure CMP-1253.
The inspectors reviewed Maintenance Procedure CMP-1253, "Limitorque Motor-0perated Valves," Revision 9, which provides control of torque switch settings through a list of stated minimum / maximum values. The inspectors
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concluded that this procedure provided an acceptable method of controlling switch setpoints.
Other Weaknesses
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The licensee had no plans to refurbish MOVs prior to testing. As a result,
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the baseline physical condition of the tested MOVs would not be kncwn.
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m
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-14-The inspectors concluded that the licensee has established a policy regarding pre-testing maintenance on MOVs in order to establish a known baseline condition.
Some MOVs had a significant amount of lubricant placed on the smooth portion of the stem, which passes through the packing.
l
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Maintenance Procedure PMP-1205, " Motor-Operated Valve Routine Maintenance,"
l Revision 7, was changed. A note was added to apply lubricant to the threads i
only and not to apply lubricant to the unthreaded portion of the stem. The j
inspectors concluded that the procedure revision satisfactorily addressed the problem.
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2 FOLLOWUP (92701)
2.1 (open) Inscector Followuo Item (50-458/9124-01): Temperature Effects on AC IAlternatino Currentl Motors This item addressed temperature effects on ac motor performance. The licensee intended to evaluate temperature effects on ac motor performance for their MOVs when the valve operator vendor (Limitorque) completes an ongoing study.
Limitorque has not issued an estimated completion date for this study. The licensee's evaluation of temperature effects on motor performance will be evaluated during a future inspection. This inspector followup item remains open.
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ATTACHMENT'
_1 PERSONS CONTACTED 1.1 Licensee PersoDad
- D. Andrews, Director, Quality Assurance
- T. Anthony, Supervisor, Plant Performance and Test
- R. Backen, Supervisor, Quality Assurance Systems
- R. Biggs, Supervisor, Operations Quality Control
- L. Borel, Senior Mechanical Engineer-
- R. Buell, Supervisor, Nuclear Steam Systems
- B. Chutstz, Senior Engineer
- J. Cook, Senior Technical Specialist
- D. Derbonne, Assistant Plant Manager, Operations
- C. Fisher, Quality Assurance Engineer
- A. Garrett, Senior Electrical Engineer
- J. Hamilton, Manager, Engineering.
- D. Hartz, Outage Director
- T. Hoffman, Supervisor, Civil / Structural Design
- G. Kimmell, General Maintenance Supervisor
- D. Lorfing, Supervisor, Nuclear Licensing
- J. Maher, Licensing Engineer
- I. Malik,- Supervisor, Operations Quality Assurance
- J. Mead, Supervisor, Electrical and Special Projects
- J. Miller, Director, Engineering Analysis
- S._ Radebaugh, Assistant Plant Manager-Maintenance
- J. Richmond, Senior System Engineer
- J. Salmon, Motor-Operated Valve Program Coordinator
- M. Stein, Director, Design Engineering 1.2 NRC Personnel
- A. Singh, Reactor Inspector
- T. Gaines, Radiation Specialist
- H. Bundy, Reactor Inspector
- M. Murphy, Reacto* Inspector
- W. Smith, Senior Rt.sident Inspector In addition to the personnel listed above, the inspectors contacted other personnel during the inspection.
- Denotes personnel that attended the exit meeting.
2 EXIT MEETING An exit meeting was conducted on April 2, 1993. During this meeting,-the inspectors reviewed the scope and findings of the report. _The licensee did not-identify as proprietary any information provided to, or reviewed by, the inspectors.
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