IR 05000445/1993023
| ML20045E778 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 06/21/1993 |
| From: | Westerman T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20045E773 | List: |
| References | |
| 50-445-93-23, 50-446-93-23, NUDOCS 9307060032 | |
| Download: ML20045E778 (9) | |
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APPENDIX U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Inspection Report:
50-445/93-23 50-446/93-23
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Operating License:
NPF-87 NPF-88 Licensee: TV Electric Skyway Tower 400 North Olive Street, L.B. 81 Dallas, Texas 75201 Facility Name: Comanche Peak Steam Electric Station (CPSES)',-Units 1 and.2 Inspection At: CPSES, Glen Rose, Somervell County, Texas Inspection Conducted: May 24-28, 1993 Inspectors:
P. A. Goldberg, Reactor Inspector, Engineering Section Division of Reactor Safety W. M. McNeill, Reactor Inspector, Engineering Section
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Division of Reactor Safety
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Approved:
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g-2/- 94-Thomas F. Westerman, Chief, Engineering Section Date Division of Reactor Safety Inspection Summary Areas Insoected (Unit 1 and Unit 21: Routine, announced inspection of'
maintenance activities on motor-operated valves.
Results (Unit I and Unit z):
The failures of motor-operated valves were properly identified and
corrected.
The lack of trending motor-operated valve failures was considered a
weakness (Section.2.2).
Unit 1 work histories could not be retrieved by valve number and Unit 2
work histories-were not in'a data base. These were considered weaknesses (Section 2.2).
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9307060032 930629 PDR ADOCK 05000445 G
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Lack of documentation in the operability' determination on operations notification and evaluation forms was considered a weakness (Section 2.2).
Attachments:
Attachment 1 - Persons Contacted and Exit Meeting
Attachment 2 - Documents Reviewed
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-3-DETAILS 1 PLANT STATUS
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During this inspection period, Unit I was in Mode 1 and Unit 2 was in an outage.
2 GENERIC LETTER (GL) 89-10 " SAFETY-RELATED MOTOR-OPERATED VALVE (MOV)
TESTING AND SURVEILLANCE" (TI 2515/109)
On June 28, 1989, the NRC issued GL 89-10 " Safety-Related Motor-Operated Valve Testing and Surveillance," which requested licensees and construction permit holders to establish a program to ensure switch settings for safety-related M0Vs were selected, set, and maintained properly. On January 14, 1991, the NRC issued Temporary Instruction (TI) 2515/109, " Inspection Requirements for Generic Letter 89-10, Safety-Related Motor-0perated Valve Testing and Surveillance," to provide instructions for the inspection of MOV programs.
The TI was divided into two parts. The first was for the inspection of the program development.
The second part t:as for the inspection of the implementation of the program. The results of the Part 1 inspection are documented in NRC Inspection Report 50-445/91-51; 50-446/91-51. The results of the Part 2 inspection are documented in NRC Inspection Report 50-445/93-10; 50-446/93-10.
This inspection was a continuation of the Part 2 inspection. The inspectors used the guidance of TI 2515/109 Part 2 to perform this inspection.
The-inspectors reviewed failures identified on the site nonconformance and corrective action reports.
In addition, the inspectors reviewed corrective maintenance work orders.
2.1 Qggrations Notification and Evaluation Forms-During the Mid-Cycle Outage, Spring of 1991, 13 of the 123 Unit I valves in the program, were refurbished. During Refueling Outage 1, Fall 1991, 50 valves were refurbished and 40 valves were given a static' baseline test.
Thirty-four valves were satisfactory and 6 unsatisfactory. -The 6 unsatisfactory valves were " accepted-as-is" by engineering on operations notification and evaluation (0NE) forms.
During Unit 1 Refueling Outage 2, Fall of 1992, 30 valves were refurbished, 48
given a baseline test, 35 were given a post-baseline test, and 5 were given.a
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re-baseline test.
Four of the 48 were unsatisfactory in baseline testing and were evaluated " accepted as-is" on ONE forms. Of the 35 given a post-baseline test, 2 were unsatisfactory and accepted on ONE forms.
The 5, which required a retest, were retested because of stem replacement in 4 cases and because of a motor replacement in one case.
In Refueling Outage 3, it is planned to refurbish 30 valves and baseline test 35. All 119 Unit 2 valves have been given a baseline test during start up testing and there had been no post-baseline testing.
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-4-The. inspectors found that Technical Support Procedures Nos. TSP-710, " Motor-operated Valve Program," Revision 0, and TSP-711, " Motor-operated Valve Performance Monitoring and Trending," Revision 0, became effective on May 1, 1993. The program as defined in Station Administration Manual, STA-754,
" Motor-operated Valve Program," Revision 0, with Procedure Change I was also effective on May 1, 1993. The inspectors did note that the previous program descriptions were in Memoranda CPSES-9108503, dated March 27, 1991, for. Unit 1 and CPSES-9111160, dated May 9, 1991, for Unit 2.
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The inspectors reviewed the quarterly plant equipment failure history and-performance reports from 1991 to present.
Categories of component failures were motor operators, valve operators, and valves-Limitorque.
This activity was driven by Procedure REI-502, " Equipment History Trending." There were no trends identified in these reports.
The inspectors found that plant performance operating reports from 1991 did address MOV issues; however, specific trends were not identified.
The inspectors requested a printout of ONE forms associated with the valves identified in the program. This printout identified 160 ONE forms since 1991.
The inspector identified apparent trends in the printouts.
For example, 17 of the ONE forms identified some problem with the nameplates.
Sixty-two were associated with the program testing. Twelve were associated with wiring problems (nicked irsulation, mislabeled, miswired, etc.). Three ONE forms were generated during the Unit 1 Refueling Outage.1 and 9 ONE forms during the Unit 1 Refueling Outage 2 on the failure to meet the 80 percent voltage pullout torque limit.
The inspectors reviewed 37 ONE forms associated with the MOV testing program.
This review included the disposition and corrective actions taken to resolve the identified problems. The disposition and corrective actions reflected sound engineering judgement.
During the baseline testing of the Unit 1 Refueling Outage 1, the inspectors found 23 ONE forms were written on test problems, i.e.,. failure to meet torque requirements or thrust requirements. During the Unit 1 Refueling Outage 2, there were 18 ONE forms written on test problems associated with baseline testing.
In addition, there were 9 ONE forms associated with post-baseline testing.
The inspectors noted that trending of failures during the MOV testing, surveillance or local leak rate testing, and second testing failures of
" families" (operators and valves of the same configuration) had not been l
performed for the last several years.
The inspectors considered this to be a l~
weakness. After this weakness was identified by the inspectors, the licensee
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made available an independent safety review group assessment report, which previously identified the failure to trend.
This report was completed prior to the issuance of the trend procedures, which were issued May 1993.
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2.2 Review of Corrective Maintenance Work Packages The inspectors requested a computer printout of work histories for all the
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MOVs within the scope of GL 89-10, " Safety-related Motor-operated Valve Testing and Surveillance," by valve tag number. The request was made for Unit 1 for the period since it started operation and for Unit-2 since baseline MOV testing was performed during startup. The work histories for Unit.1 valves by valve tag.could not be readily retrieved.
The licensee had to generate a program to sort the work histories by valve tag number.
In addition, the work histories for the Unit I valves were on two different data bases, which could not be combined. The Unit 2 work histories were not on any data base. The work histories for the Unit 2 valves were in startup records, which would have to be manually retrieved. The inspectors considered the inability to generate a work history sorted by valve tag number for the GL 89-10 MOV valves for Unit 1 and the manual retrieval of work histories for Unit 2 to be weaknesses in the MOV trending program.
The inspectors selected and reviewed the work histories of 11 of the Unit 1 MOVs in the GL 89-10 program. Of the 11 valves reviewed, the inspectors did not identify any valves which required repeat maintenance to be performed.
Valve problems identified in the maintenance work orders appeared to be properly corrected. The maintenance work orders reviewed were from the first Unit 1 Mid-Cycle Outage, Refueling Outage 1, and Refueling Outage:2.
Attachment 2 to this report is a summary of the maintenance work histories for the 11 valves.
2.2.1 ONE Form 92-1425 The inspectors reviewed ONE form 92-1425, which was generated December 3, 1992, for a component cooling water containment isolation MOV, Tag No. 1-HV-4701-MO.
This ONE form was initiated because the motor burned out during a differential pressure test. The ONE form stated that the close limit switch did not trip when the valve was in the closed position, thereby, burning out the motor and exceeding the allowable thrust and torque values.
In addition, the ONE form stated that when declutching the rotors for installation of a load cell prior to testing, the close limit switch rotor did not appear to fully disengage, allowing the rotor setting to drift. The ONE form concluded that the valve was operable prior to the differential pressure test. The inspectors questioned the licensee how the valve operability had been determined, since the ONE form lacked sufficient detail to determine if the valve had been operable or not. The licensee stated that the valve had been static tested November 22, 1992, and had passed'the test with the close limit switch functioning properly.
The ONE form justified the valve being over thrust and over torqued due to the valve exceeding its normal Limitorque actuator ratings. The one-time Limitorque allowable thrust rating for the valve was 35,000 pounds and the measured thrust was 28,432 pounds. The one time allowable torque rating was
.500 foot pounds and the measured torque was 363 foot pounds. The ONE form disposition concluded that the thrust and torque developed during the testing
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-6-were acceptable and no additional inspections were required other than normal MOV maintenance. The ONE form did not indicate any further testing; however, after a new motor was installed, the valve again had a differential pressure test performed and the results were satisfactory. The licensee stated that the traces from the test were found acceptable; therefore, they concluded that none of the internals of the MOV had been damaged during the previous test.
The licensee also indicated that a diagnostic test would be performed again in the fall of 1993, and if any degradation was found, the valve would be
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disassembled and inspected.
The inspectors observed that the ONE form lacked sufficient detail to determine operability prior to valve failure.
The licensee's engineers had the appropriate information but had not documented it.on the ONE form.
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2.2.2 ONE form 92-1427 The inspectors reviewed ONE form 92-1427, which was generated December 4, 1992, due to a burned out motor and the MOV, Tag No. 1-FV-4772-2, being over thrust.
The ONE form stated that the motor had been energized prior to the start of the test. The inspectors questioned why the motor had been energized. The licensee stated that there had been a lack of coordination between a danger tag and test tag installed on the valve prior to the test being performed. A danger tag had been placed on the valve and then removed prior to the test tag being installed.
The motor had been energized after the danger tag was removed. The licensee stated that the current practice is to install both the danger tag and the test tag at the same time.
The ONE form stated that the maximum estimated stall thrust was 36,495 pounds, which exceeded the Limitorque allowable one-time thrust limit of 35,000 pounds. Due to exceeding the one-time limit, the ONE form disposition required that the valve and actuator be disassembled and inspected and the actuator top housing cover bolts were replaced. The inspectors reviewed Maintenance Work Order No. 1-92-030225, dated December 5, 1992, which performed the inspection and part replacement required by the ONE form. After the valve was inspected and rebuilt, a static test was performed and the results were satisfactory.
The inspectors observed that the ONE form did not contain sufficient detail to determine the cause of the motor burnout and MOV overthrust or to determine if the valve was operable prior to valve failure. Again, the licensee's engineers had the details required but had not documented them on the ONE form.
2.3 Conclusion The failures of MOVs were properly identified and corrected. Two weaknesses were noted in trending of failures and the lack of ready retrieval of work histories. A weakness was noted in that the ONE forms lacked sufficient documented detail to determine operabilit.
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ATTACHMENT 1
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1 PERSON CONTRACTED 1.1-Licensee Personnel
- 0. Bhatty, Licensing Engineer
- W. Black, Design Engineering
- W. Cahill, Group Vice President
- R. Carter, Staff Engineer C. Catino, Test Engineer
- P. Chiu, Design Engineer
- S. Cutchen, Maintenance Outage Coordinator
- D. Davis, Plant Analysis Manager
- J. Donahoe, Operations Manager
- R. Flores, Shift Operations Manager
- J. Gallman, Trend Analysis-Manager J. Green, Engineer
- T. Hope, Site Licensing Manager
- D. Kross, Shift Operations Manager
- B. Lancaster, Plant Support Manager
- D. Manning, Test Lead
- H. Marvray, Supervisor of Technical Programs
- D. McAfee, Quality Assurance Manager
- D. Moore, Maintenance Manager
- J. Muffett, Manager of Technical ' Support / Design Engineering
- W. Ross, Maintenance Engineer L. Strope, Plant Analysis Engineer
- R. Withrow, Component Test Engineer 1.2 NRC Personnel
- H. Bundy, Reactor Inspector
- R. Latta, Resident Inspector
- G. Werner, Resident Inspector In addition to the personnel listed above, the inspectors contacted other personnel during this inspection period.
- Denotes personnel that attended the exit meeting.
2 EXIT MEETING An exit meeting was conducted on May 28, 1993.
During this meeting, the inspectors reviewed the scope and findings of this report. The licensee did not identify as proprietary any information provided to, or reviewed by,- the inspectors.
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ATTACHMENT 2 M0V Maintenance Histories MOV Tag No. 1-HV-4777 Work Order No. C910000656, 3/9/91, install new packing.
Work Order No. C910001618, 4/4/91, reset open limit switch to improve stroke time and retested valve.
Work Order No. C910001662, 4/8/91, valve had failed local leak rate test (LLRT) due to excessive leakage after valve refurbishment.
Reset torque switch from 2.0 to 2.75 and diagnostic testing completed.
Valve passed LLRT.
MOV Tag No. 1-HV-4708 Work Order No. C910000631, 3/9/91, repacked and stroked valve.
Work Order No. C910001896, 4/23/91, valve had failed LLRT.
Reworked valve and weld repaired crack in valve wedge.
Retested valve and found satisfactory.
Work Order No. 1-92-031258, 12/13/92, valve had failed LLRT.
Valve seats were lapped and valve successfully tested. ONE Form 92-1074 generated to fix seats by building up guides'on disc for a tighter seat.
Work planned for the next outage.
MOV Tag No. 1-8100 Work Order No. C910010957, 11/13/91, valve position indicator light would not light when MOV closed. Cleaned contacts on rotor.
Work Order No. 4-92-001827, 5/31/92, repacked valve.
Work Order No. 4-92-001830,10/8/92, refurbished actuator and performed baseline static test.
MOV Tag No. 1-HV-4758 Work Order No. C910003220, 6/3/91, performed tests.
Work Order No. C910000651, 10/22/91, inspected and refurbished M0V.
NOV Tag No. 1-HV-2480 Work Order No. C910000602, 3/8/91, replaced packing and stroked valve.
Work Order No. C910000603, 3/16/91, during actuator refurbishment found stem nut with abnormal wear patterns. ONE form 91-601 was prepared and allowed use of stem nut until next refueling outage.
Work Order No. C910002122. 7/19/91, installed new stem nu..
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MOV Tag No. 1-FV-4772-1-Work Order No. C910003762, 6/3/91, performed spring pack testing.
Work Order No. C910000644, 6/4/91, performed actuator refurbishment.
Work Order No. C910000643, 10/22/91, valve stem found with runout.
ONE Form 91-1107 justified the use of the repaired stem.
Work Order No. 1-92-022024, 9/24/92, replaced valves stem in accordance with Design Modification 92-021.
MOV Tag No. 1-FV-4773-1 Work Order No. C910003770, 6/3/91, performed routine shop testing.
Work Order No. C910000647, 10/22/91, inspected and refurbished.
Work Order No. 1-92-022026, 9/24/92, replaced valve stem in accordance with Design Modification 92-021.
Mov Tag No. 1-HV-4699 Work Order No. C910000626, 7/11/91, during actuator refurbishment, replaced a rotor and gear.
Work Order No. C910005675, 7/13/91, performed shop tests and determined spring pack was a different number. ONE Form 91-1153 prepared.
Work Order No. C910010294, 10/27 C1, restamped nameplate to correct spring pack identification numbei.
MOV Tag No. 1-HV-5543 Work Order No. 92-021295, 8/13/92, reworked valve to stop seat leakage.
Found metal shavings on upstream side of valve.
Work Order No. 92-025260, 10/7/92, performed shop tests.
HOV Tag No. 1-HV-4287 Work Order No. 92-001486, 10/3/92, verified handwheel closed in counter-clockwise direction and verified torque switch was wired for reverse action.
MOV Tag No. 1-HV-5542 Work Order No. 92-025259, 10/7/92, perforned satisfactory shop tests.
Work Order No. 92-029872, 12/2/92, replaced seat rings.
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