IR 05000269/1988016
| ML16127A198 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/13/1988 |
| From: | Jape F, Tingen S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML16125A396 | List: |
| References | |
| 50-269-88-16, 50-270-88-16, 50-287-88-16, IEB-85-003, IEB-85-3, IEIN-86-034, IEIN-86-34, NUDOCS 8808040070 | |
| Download: ML16127A198 (7) | |
Text
r RREG&4 UNITED STATES NUCLEAR REGULATORY COMMISSION REGION il 101 MARIETTA ST., ATLANTA, GEORGIA 30323 Report Nos.:
50-269/88-16, 50-270/88-16, and 50-287/88-16 Licensee:
Duke Power Company 422 South Church Street Charlotte, NC 28242 Docket Nos.: 50-269, 50-270, License Nos.: DPR-38, DPR-47, and and 50-287 DPR-55 Facility Name:
Oconee Nuclear Station, Units 1, 2, and 3 Inspection Conducted: May 23-27, 1988 Inspector:
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B S. Tingen D te Signed Approved by: 6
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/,- Jap 7 Chief Date Signed
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Test Programs Section Engineering Branch Division of Reactor Safety SUMMARY Scope:
This routine, announced inspection was conducted in the areas of Complex Surveillance Testing and IE Bulletin Follow-u Results: In Paragraph 3 weaknesses were identified in the licensee IE Bulletin 85-03 program that involved failure to differential pressure test motor operated valves in accordance with bulletin guidelines, and a failure to perform post-maintenance motor operated valve testing per a previous licensee commitmen Strengths were identified in the licensee IE Bulletin 85-03 program that involve the following licensee commitments:
1. Expand the scope of Bulletin 85-03 to all safety-related valve. Perform diagnostic testing on bulletin valves each refueling and following maintenance that could effect stem thrus. Construct a full flow high pressure test loop in order to
perform additional testing of motor operated valve PDR ADOCK 05000269 G
PNU
REPORT DETAILS 1. Persons Contacted Licensee Employees
- T. Mathews, Regulatory Compliance
- B. Millsaps, Maintenance Service Engineer
- F. Owens, Regulatory Compliance
- D. Sweigart, Operations Superintendent
- M. Tuckman, Station Manager J. VanSurdam, Technical Support Engineer, Valve Maintenance Other licensee employees contacted during this inspection included craftsmen, engineers, mechanics, and technician NRC Resident Inspector
- P. Skinner
- Attended exit interview 2. Complex Surveillance (61701)
The inspector reviewed (1) the results of Main Steam Safety Valve (MSSV)
setpoint testing, (2)
MSSV set point test procedure, and (3) the licensee's action in response to IE Information Notice 86-05, Main Steam Safety Valve Test Failures and Ring Setting Adjustments. The acceptance criteria for MSSV set point testing is contained in Oconee Technical Specifications which invokesSection XI of the 1980 ASME Boiler and Pressure Vessel Code which in turn invokes ANSI/ASME PTL 25.3-1976, Safety and Relief Valves Performance Test Code Oconee has eight self-actuated MSSVs located on each main steam line for a total of 16 valves per Unit to prevent over pressurization of the main steam system under all conditions. Oconee MSSVs are Crosby Model No. 6R10 and are welded in plac The valves are set point tested in place while in Mode 3 with use of pneumatic-assist equipmen The inspector reviewed Oconee Procedure MP/0/A/1200/89, Main Steam Safety Valves Set Point Test, in order to verify compliance with ANSI/ASME PTC 25.3-1976 requirements for MSSV set point testing. The only discrepancy noted was that Procedure MP/O/A/1200/89 did not make the proper elevation corrections to the test gage used for the test. The pressure pertinent to testing was the main steam pressure; however, the test gage was located below the main steam line with a vertical column of water between the gage and main steam line. As a result Oconee MSSVs are set approximately 4 psi lower than intende The inspector did not.consider this a significant safety issue; however, the licensee initiated a revision to the procedure
to account for the 4 psi pressure differentia The inspector reviewed the most recent MSSV setpoint test results obtained per procedure MP/0/A/1200/89 for Units 1, 2, and Due to the excessive number of valves requiring setpoint adjustment all of the MSSVs were tested during each unit refueling outag MSSVs set point tolerances are +/-1%.
The majority of the valves that failed did not exceed 2% of the set point; however, several valves were 3% out of tolerance. The inspector considers that Section XI ASME Boiler and Pressure Code requirements regarding MSSV setpoint testing were me The inspector also noted that Oconee has developed and implemented a program to overhaul four MSSVs during each refueling outage. This was initiated due to the excessive MSSV blowdown experienced following reactor scram IE Information Notice 86-05, Supplement 1, addresses MSSVs failure to achieve manufacturers stated flow rates due to inappropriate ring setting The Information Notice discusses Vogtle 1 MSSVs that are the same manufacture and model number as Oconee MSSVs. With a nozzle ring setting of +150 and guide ring setting of -45 the Vogtle 1 MSSVs failed to provide the manufacturer specified relieving capacity when tested. The ring settings had to be changed in order for the Vogtle 1 MSSVs to achieve the adequate relieving capacity. Present Oconee MSSVs are set at a nozzle ring setting of +150 and a guide ring setting of -50 which is similar to the Vogtle 1 MSSV ring settings that did not achieve the manufacturer stated flow rate Oconee Final Safety Analysis Report states that the combined MSSV relief capacity for the 16 MSSVs is 13,105,000 lb/hr, and that the MSSV setpoint pressure is based on a 4% blowdown. Discussion with the licensee indicates that at the present MSSV ring settings 4lowdown is approximately 6% to 7%. In order to determine if present MSSV flow capacity and blowdown are adequate to prevent over pressurization of the main steam system the licensee has joined the Westinghouse Owner's Group who is presently involved in testing Crosby safety valves. In mid June the owners group is scheduled to complete testing and by July issue a final repor Oconee action concerning appropriate ring settings to establish adequate flow and blowdown will be based on the Owners Group Repor. IE Bulletin Followup (25573)
(Closed) 50-269, 270, 287/85-BU-03/ T2515/73, "Motor Operated Valve Common Mode Failures 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 maintained. Action Item b of the bulletin requires that correct switch settings be established, Item c requires differential pressure testing or alternate methods to demonstrate operability with the settings from Item b; Item d requires plant procedures to be provided to assure the maintenance of correct switch settings throughout plant lif Duke Power Company, letter dated January 14, 1988, provided the Oconee Nuclear Station (ONS) final response to Bulletin 85-0 In order to evaluate the ONS Bulletin 85-03 program the inspector held discussion with appropriate licensee personnel and reviewed the following:
Procedure MP/O/A/1210/01, Operator - Limitorque -
SMB/SB Series Removal and Replacemen Procedure IP/O/A/3001/11A, Testing of Rotork Operators Using MOVAT Procedure MP/O/A/1210/4, Operator, Limitorque SMB-0 Through SMB-4T, and SB-O Through SB-4, Disassembly, Repair, and Reassembl Procedure IP/O/A/3001/10, Maintenance of Limitorque Valve Operator Procedure IP/O/A/3001/11, Testing of Limitorque Operators using MOVAT Completed MOVATS data packages for bulletin valves 3FDW-347, 1HP-27, 1FDW-47, 1C-391, 2MS-84 and 3HP-Maintenance history and selected work requests dating back to 1986 for bulletin valves 1HP-27, 1FDW-47, 1C-391, 2MS-84, 3HP-4, 2HP-3, 2HP-25, 2HP-410, 1HP-26, IMS-82, 1HP-20, 3HP-24, 3HP-409, and 3MS-8 Training Qualification records for selected MOVATS and MOV maintenance personne Operation of Bulletin MOVs at degraded voltage Duke Power Company Final Bulletin 85-03 response contained in letter dated January 14, 198 Except for the following, the inspector considers that the ONS Bulletin 85-03 program meets or exceeds bulletin requirements:
a.Bulletin 85-03 requires that following establishment and setting of switches, MOVs be demonstrated operable by stroke testing the valve while at the maximum differential pressure. If differential pressure stroke testing cannot be performed, justification is required to be provide This justification should include the alternative to maximum differential pressure stroke testing. The ONS Bulletin 85-03 program identified 14 valves for each uni Seven of the 14 Unit 1 valves were differential pressure stroke tested, no Unit 2 or 3 valves were differential pressure teste The inspector questioned if differential pressure stroke testing of only seven Unit 1 MOVs met Bulletin 85-03 requirements. On June 2, 1988, a conference call was held between NRR, Region II NRC, and Duke Power Company Corporate and ONS personnel to discuss this issu During this conference call differential pressure stroke test alternatives were discusse The conference call ended with the licensee agreeing to provide to the NRC additional information concerning differential pressure stroke testing of bulletin valve This issue may also effect other Duke
Power Company bulletin valve program differential pressure stroke testin This is identified as Inspection Followup Item (IFI)
88-16-01, Bulletin Valve Differential Pressure Stroke Testin b. In the ONS response to Bulletin 85-03 Duke Power committed to perform post maintenance testing on bulletin valves or actuators where maintenance could affect available stem thrust, such as packing adjustment or replacement, torque switch replacement or other actuator maintenance to require one of the following retests:
1) Complete signature analysis retest, including spring pack calibration, to reestablish specified available thrust at torque switch tri ) Motor control center MOVATS motor load monitoring to ensure established running load threshold value is not exceede ) A spring pack displacement signature for actuators which have no spring pack preload to quantify changes in running loa Review of bulletin Valve 1HP-27 maintenance history indicated that on December 30, 1987, the packing was adjusted without any subsequent MOVATS testing. 1HP-27 packing was adjusted while Unit 1 was operat ing and the Unit has not been shutdown since 1HP-27 packing was adjusted. The license did not desire to MOVATS test 1HP-27 while Unit 1 was operating and has not developed the technique to perform motor control center load monitoring. 1HP27 identified an instance where packing was adjusted when operating and post maintenance testing was not accomplished as committed. This is identified as IFI-88-16-02, Bulletin valve post maintenance testin c. The inspector reviewed numerous valve maintenance histories, MOV 1HP-27 packing adjustment was the only example found where post maintenance MOVATS testing was not accomplished, however there was no consistent administrative system to document that MOVTS testing was required following maintenanc In some casesSection VII of the work request would specify that MOVATS testing was required and other times the work request would not specify that post maintenance MOVATS testing was require Examples of work requests that performed maintenance which effects available MOV stem thrust that did not specify post maintenance MOVATS testing was required are #53278, 51291, and 9145 These work requests replaced packing, adjusted packing and replaced a torque switch. Some MOV maintenance procedures contained instructions to notify MOVATS personnel when the maintenance was completed and other procedures did not contain such instruction There appeared to be a high level awareness by the licensee personnel involved with MOV maintenance and testing, and therefore, post mainten ance testing was being accomplished as committed with the exception of 1HP-27 packing adjustment. In the case of 1HP-27, MOVATS personnel were aware that the packing was adjusted but did not test because of reasons previously discussed. The need to document MOV post maintenance
testing as committed to in the Bulletin 85-03 response is identified as IFI 88-16-03, Administrative Documentation of MOV Post Maintenance Testin d. Action Item f of Bulletin 85-03 requires licensee's to report the bulletin program findings as to valve operability prior to any adjustment preformed as a result of the bulleti In Duke Power Company response to action Item f, MOVs 1HP-3, 1HP-4, 1HP-20, 2HP-3, 2HP-4, and 3HP-20 were reported to have lower than required as found thrust outputs, but operability of these valves has not yet been determined.Bulletin 85-03 requires the valves to be reported to the NRC if determined to be inoperabl This is identified as IFI 88-16-04, Determine and Report Operability of Under Thrusting Valve e. Duke Power Company letter dated January 14, 1988, reports that MOVs 1HP-3, 2HP-3, 2HP-20, 3HP-3, 3HP-4, 3HP-20 and 3MS-84 as left closing thrust values exceed the 2000 cycle actuator rating recommended by Limitorque. Action is being taken to expand the present actuator limits or reduce the required thrust but is not complete. In order to address long term operability of these over thrusting actuators this needs to be resolved and will be tracked by the NRC until resolved. This is identified is IFI 88-16-05, Corrective Action for overthrusting MOV f. I.E. Information Notice 86-34, Improper Assembly, Material Selection, and Test of Valves and Their Actuators, discusses the need to place a MOV in mid stroke when torquing the valve to actuator fastener If the valve is closed when torquing the valve to actuator fasteners, the bolt preload may be transferred through the stem to the valve dis When the valve is opened the bolts are relaxed and have a low or no preloa Such a condition, particularly in the presence of high vibration, will cause early fatigue failure of bolt ONS procedures that install actuators do not specify to place the valve in the mid position when torquing valve to actuator bolts. This is identified as IFI 88-16-06, Placement of Valve in Mid Position Prior to Torquing Valve to Actuator Fastener During the inspection, the inspector noted the following strengths in the Bulletin 85-03 program:
a. In letter dated November 20, 1986, Duke Power Company committed to expand the scope of Bulletin 85-03 to all ONS safety related MOVs that are required to be tested for operational readines b. In letter dated January 14, 1988, Duke Power Company committed to perform post maintenance diagnostic testing on all bulletin valves where maintenance could effect available stem thrust, and in addition diagnostic test bulletin valves each refueling in order to verify operabilit c. Duke Power Company has constructed a full flow high pressure test loop in order to perform tests on MOVs identical to those
installed in ON Test parameters will include stem packing loads and under voltage effect NRR review of the licensee's May 16, 1986, November 20, 1986, February 18, 1987, September 17, 1987, and September 29, 1987 responses to action item e of Bulletin 85-03 indicates that the selection of the applicable safety-related valves and the valve's maximum differential pressures meets the requirements of the bulletin, and the program to assure valve operability requested by action item e of the bulletin is now acceptable. This item is closed by Region II. NRR review of the licensee response to action item f of the bulletin is in process and additional information may be requested as a result of this revie No violations or deviations were identifie. Exit Interview The inspection scope and results were summarized on May 27, 1988, with those persons indicated in paragraph 1. The inspector described the areas inspected and discussed in detail the inspection results listed belo Proprietary information is not contained in this repor Dissenting comments were not received from the license Item Number Description IFI-88-16-01 Bulletin Valve Differential Pressure Stroke Testing IFI-88-16-02 Bulletin Valve Post Maintenance Testing IFI-88-16-03 Administrative Documentation of MOV Post Maintenance Testing IFI-88-16-04 Determine and Report Operability of Under Thrusting Valves IFI-88-16-05 Corrective Action for Overthrusting MOVs IFI-88-16-06 Placement of Valve in Mid Position Prior to Torquing Valve to Actuator Fasteners