IR 05000313/1987009
| ML20206H372 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/09/1987 |
| From: | Ireland R, Norman D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20206H370 | List: |
| References | |
| 50-313-87-09, 50-313-87-9, 50-368-87-09, 50-368-87-9, IEB-85-003, IEB-85-3, NUDOCS 8704150338 | |
| Download: ML20206H372 (5) | |
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APPENDIX U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
NRC Inspection Report:
50-313/87-09 Licenses:
DRP-51
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50-368/87-09 NPF-6 Dockets:
50-313 50-368 Licensee:
Arkansas Power & Light Company (AP&L)
P.O. Box 551 Little Rock, Arkansas 72203 Facility Name: Arkansas Nuclear One, Units 1 and 2 Inspection At:
Russellville, Arkansas Inspection Conducted:
March 9-13, 1987 Inspector:
[h 4'/9/67 D. E. Norman, Reactor Inspector, Engineering Ddte'
Section, Reactor Safety Branch Approved:
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Y/9h7 R. E. Irel And, Chief, Engineering Section 06te '
h Reactor Safety Branch Insepction Summary Inspection Conducted March 9-13, 1987 (Report 50-313/87-09; 50-368/87-09)
Areas Inspected:
Routine unannounced inspection of IE Bulletin (IEB) 85-03 Program Implementation for Unit 1 and followup on previously identified inspection findings for Units 1 and 2.
Results: Within the areas inspected, no violations or deviations were identified.
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-2-DETAILS
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Persons Contacted Arkansas Power and Light Company (AP&L)
- D. Lomax, Plant Licensing Supervisor
- S. Quennoz, General Manager, Plant Operations i
- P. Michalk, Plant Licensing Engineer
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- D. Howard, Special Projects Manager
- E. Ewing, General Manager, Plant Support
- J. McWilliams, Maintenance Manager
- B. Baker, Operations Manager
- L. Humphrey, General Manager, Nuclear Quality
- J. Taylor-Brown, QC Superintendent M. Browning, Maintenance Engineer, Nuclear Operations G. Kendrick, I&C Supervisor B. Lovett, Maintenance Engineer, Nuclear Operations NRC
- C. Harbuck, Resident Inspector
- D. Norman, Reactor Inspector
- Denotes those present at the exit interview on March 13, 1987.
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Inspection Summary a.
IEB 85-03 (Unit 1)
IEB 85-03, " Motor Operated Valve Common Mode Failure During Plant Transients Due to Improper Switch Settings," was issued as a result of several events during which motor operated valves (MOVs) failed on demand due to improper switch settings.
The Bulletin requested that MOVs in certain systems be tested for operational readiness, and that licensees develop and implement a program to ensure that valve operator switches are selected, set, and maintained properly to accommodate maximum differential pressure expected during both opening and closing of the valve for both normal and abnormal events within the design basis.
The licensee made a submittal requested by a
the Bulletin to the NRC on May 14, 1986, and an additional submittal of information requested by the NRC was made on October 1, 1986.
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This inspection was performed to followup on the licensee's activities taken in response to IEB 85-03 and commitments made by the licensee in submittals regarding the bulletin.
The inspection scope included the following:
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-3-(1) Procedures Review - The IEB 85-03 program is implemented by Procedure 1409.56, Revision 1, dated June 16,1986, " Motor
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Operated Valves IEB 85-03 Program, EQ Inspection and PM Work Plan," which sets limits, presents instructions, and serves as a traveler for action required for the program.
The following procedures, which implement the program procedure, were also reviewed by the NRC inspector:
1409.14, Revision 4, dated November 3, 1986, " Delta P Testing Procedure"
1403.31, Revision 2, dated September 2, 1986, " Testing of Motor Operated Valves Using the MOVATS 2100 (As Found)"
1403.32, Revision 0, dated September 10, 1986, " Testing of Motor Operated Valves Using the M0 VATS 2100 (As Left)"
1403.160, Revision 7, dated September 16, 1986, "Limitorque Motor-Operated Valve SMB-000 Maintenance"
1403.161, Revision 4, dated September 17, 1986, "Limitorque
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Motor-Operated Valve SMB-00 Maintenance" 1403.162, Revision 7, dated November 3, 1986, "Limitorque Motor-Operated Valve SMB-0 Through SMB-04 Maintenance" Practices for accurately setting the switches to prevent occurrences as described in the bulletin were addressed in the procedures and included:
Specific procedure for determining switch setting values.
- Requirement that torque bypass switch settings consider system backlash.
Requirement that torque switches be set with spring pack in a relaxed condition.
- Checking for backseating by turning handwheel after tripping limit switch.
The licensee's program ~provides reliable operation of MOVs by utilizing the Motor Orserated Valve Analysis and Test System (M0 VATS), a syste( which permits testing, adjusting, and setting of limit switches, torque switches, and torque switch bypass which are part of the controls for an M0V.
MOVATS is a portable signature-analysis system designed for field use and displays and stores the following data:
axial motion of the worm
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motor current stemload(thrust)
actuations of torque and limit switches and the torque
switch bypass Sixteen of the thirty-four IEB 85-03 valves were tested in accordance with Procedure 1409.14 to comply with paragraph C. of the Bulletin, which requires that valve operability be-demonstrated at the design basis differential pressure.
In some instances where testing at the maximum differential pressure was not practical, the procedure justified an alternative method to verify correct switch settings.
In addition to the IEB 85-03 valves, the M0 VATS system was used to test MOVs within the inservice test (IST) program, equipment qualification (EQ) program, and the periodic maintenance (PM)
program of both Units 1 and 2.
(2) Hardware Inspection - Both units were operating during this inspection; therefore, no hardware inspections were performed.
(3) Data Review - IEB 85-03 reported that valves failed to operate because torque switch bypass had not been set to remain closed long enough to provide the necessary bypass function on valve opening with differential pressure conditions across the valve.
Switches were reportedly set for 5 percent of full stroke. ANO procedures require the bypass to be set at a minimum of 20 percent of full stroke (valve stem travel) on Unit 1.
Open limit switches were set to trip at approximately 95 percent of full stroke; and to ensure that backseating had not occurred, the handwheel was turned to bring the valve against the backseat after the valve travel had stopped on the limit switch trip.
Data reviewed by the NRC inspector showed that the handwheel for each valve turned a small amount, which indicated that the 95 percent setting was adequate to prevent backseating.
As-found data sh d seven valve operators which had been operating above the allowable thrust limit. A Report of Abnormal Condition (RAC) had been written in each instance and corrective action taken either to perform an analysis or to inspect the operators by magnetic particle examination.
No adverse effects were identified; however, the casing on operator CV-1406, which had exceeded the thrust limits by approximately 37 percent, had been changed.
Five operators had been identified by the licensee which were required to be left with thrust settings above design ratings and which are limited to 100 cycles of operation at the higher
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Criteria from Limitorque for the high setting are that thrust switches may be set to trip at a maximum of 10 percent above rated thrust and the final thrust due to inertia may exceed design limits by 20 percent. An internal memorandum, dated December 10, 1986, requires that overrated operators, which are identified in the control room, have each cycle, logged to determine when the 100 cycle limitation has been reached.
No violations or deviations were identified b.
Followup on Previous Inspection Items (1)
(0 pen)OpenItem 313/8632-01 - This item pointed out the need to update valve operator testing and maintenance procedures. The licensee pointed out that the procedures will be revised at a later time since they are not presently in use. This item will therefore remain open.
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(2)
(Closed) Open Item 313/8632-04 - During the previous ins a review was made of PM of Unit 1 diesel generators (DG)pection,
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Inspection of DG A had not started at that time.
In addition to the scheduled 18-month inspection, a power pack of DG A was scheduled to be disassembled and inspected for evidence of premature wear as a followup to a previous problem. Results of that inspection were reviewed by the NRC inspector and showed only normal wear. This item is considered closed.
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(3)
(Closed) Open Item 313/8632-05 - A review was done of the as-left data for valves which were identified to have excessive leakage during Unit 1 LLRT as-found tests. The valves had been repaired and retested and were within specified limits. As-left leakage rates for the LLRT were found to be within limits. This item is considered closed.
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Exit Interview The NRC inspector met with the licensee representatives denoted in paragraph 1 and with Mr. C. C. Harbuck, NRC resident inspector, on March 13, 1987, and summarized the scope and finding of the inspection.
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