IR 05000309/1993013
| ML20046D417 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 07/27/1993 |
| From: | Eapen P, Kenny T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20046D416 | List: |
| References | |
| 50-309-93-13, GL-89-04, GL-89-4, NUDOCS 9308190298 | |
| Download: ML20046D417 (12) | |
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- U.S. NUCLEAR REGULATORY COMMISSION
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REGION I
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REPORT NUMBER:
50-309/93-13.
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DOCKET NUMBER:
50-309
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L LICENSEE NUMBER: -
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.2 LICENSEE:
Maine Yankee Atomic Power Company 83 Edison Drive Augusta, Maine 04336
i FACILITY:
. Maine Yankee Nuclear Generating Station l
'I INSPECTION DATES:
June 28-July 2,1993 INSPECTORS:
J. Yerkoun, Project Engineer R. DePriest, Intern NRC LEAD INSPECTOR:
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3-IMte - I T.) teras-S'ection, EB, DRS(fenny, Sedior Reactor Engin yys 7/ 7/f3
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APPROVED BY:
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Dr. P.K.~ Eapen, Chief /
Date Systems Section, Engineering Branch Division of Reactor Safety cl
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9308190298 930811
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I PDR' ADr3CE 05000309 h;
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EXECUTIVE SUMMARY An announced inspection of the Maine Yankee Inservice Testing program and its i
implementation was conducted in accordance with NRC Temporary Instructions 2515/114,
" Inspection Requirements for Generic Letter (GL) 89-04, Acceptable Inservice Testing Programs" and Temporary Instruction 2515/110, " Performance of Safety Related Check Valves". This inspection included verification of adherence to the Code of Federal Regulations, conformance to the ASME Section XI requirements, and a general review of the licensee's IST program to ensure consistency with the provisions of GL 89-04 and an NRC l
Safety Evaluation Report, dated April 28,1992.
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A number of significant programmatic strengths were identified by the inspectors.
Procedures and oversight of testing were found to be well established and implemented. The licensee trending program for pump and valve performance was a particular strength because the data were clear, concise, and traceable through the maintenance system. The inspector found it easy to retrieve maintenance and post maintenance testing information, also trending of pumps and valves was well documented.
Two minor discrepancies were identified: Two check valves within the service water system were being tested, however, due to the procedure format, they were not being documented as tested; and a typographical error misidentified a check valve within the procedure, 3.17.4
" Primary Reactor Containment Leakage Test." Maine Yankee engineers promptly corrected these discrepancies.
With the above exceptions, the licensee IST program was determined to be effectively established and maintained to determine degradation of pumps 2nd valves before failure.
The adequacy of installed lines was inspected during a previous NRC inspection which focused on the issues of NRC Bulletin 88-04, " Potential Safety Related Pump loss," which was documented in Inspection Report No. 50-309/90-23. Four unresolved items identified in that inspection were closed during this inspection.
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DETAILS 1.0 INTRODUCTION The NRC Generic letter (GL) 89-04, issued April 3,1989, addressed several generic inservice testing (IST) program deficiencies and provided specific guidance on meeting the Code of Federal Regulations 10 CFR 50.55a(g) provisions that required adherence to the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code,Section XI, " Inservice Testing of Pumps and Valves." The NRC Temporary Instructione (TI) 2515/114, " Inspection Requirements for Generic Iztter 89-04, Acceptable Inservice Testing Programs," dated January 15,1992, and TI 2515/110, " Performance of Safety Related Check Valves," dated November 19,1991, were issued to be used by inspectors to assess the effectiveness oflicensees in providing assurance that check valves were both operable and reliable.
This inspection was conducted to review and assess the licensee's inservice testing of pumps and valves. The inspection included verification of licensee's adherence to the Code of Federal Regulations, conformance of the licensee's IST program to the ASME Section XI requirements, and a general review of the licensee IST program to ensure consistency with the provisions of GL 89-04 and an NRC Safety Evaluation Report, dated August 27,1987.
The licensee's program is required to conform to the 1983 edition of the ASME Code,Section XI.
In general, this inspection confirmed the licensee's implementation of the above listed requirements and focused mainly on the components of the Service Water, Charging and letdown, High Pressure Safety Injection (HPSI), Iow Pressure Safety Injection (LPSI) and RHR systems. The selection of these systems was based on the high risk nature of the systems regarding accident risk analysis in accordance with the Final Safety Analysis Report (FSAR). The documents reviewed during this inspection are listed in Attachment 2.
2.0 REVIEW OF THE INSERVICE TESTING PROGRAM Inservice testing is being performed under the Maine Yankee program submitted to the NRC
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on December 29,1989 in accordance with GL89-04, and the NRC Safety Evaluation, dated April 28,1992. The program was based on ASME Section XI,1986 addition of the code.
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The relief requests noted in the Maine Yankee submittal were not in conflict with Attachment
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I to GL89-04, and were primarily for check valve disassembly and inspection to confirm closure capabilities at refueling outages in lieu of testing. These relief requests were
approved by the NRC in a safety evaluation. The surveillance log, kept by the surveillance
engineer, listed the results of all valve disassembles and inspections. The inspector reviewed
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surveillance reports from 1987 to present and verified that the check valve disassembly and inspections were consistent with the position of GL 89-04.
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2.1 Check Valve Reliability Program Maine Yankee has developed a check valve reliability program with the intent to reduce the potential for check valve failures. This plan summarizes and evaluates information deemed important to the reliability of any check valve. The information is also summarized on a
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check valve data sheet which contains the following information: General information about
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the valve, system, design, installation, and maintenance history. The plan requires disassembly and inspection to monitor and trend the condition of each valve's internals. All problems and recommended changes are made to the Operations and Maintenance
departments, if needed for corrective actions. This plan is seen as a positive step toward
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increasing the reliability of system installed check valves.
2.2 Containment Isolation Valves The inspector confirmed that the containment isolation valves listed in the Technical l
Specificuions were incorporated in the Inservice Testing plan and were being tested in acaeance with the plan. The inspector witnessed Procedure 3.1.20.1 " Containment Isolation Testing at Power." This is a quarterly procedure that verifies the stroke times of containment isolation valves are within the requirements of Technical Specification 4.6
" Periodic Testing." The test was performed by knowledgeable individuals using a well
written procedure. The inspector reviewed the completed document and noted that the
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testing was satisfactory. All valves operated satisfactorily and were within the time requirements specified. In addition, the inspector reviewed procedure 3.17.4 " Primary Reactor Containment Leakage Test" the B&C portions of containment testing in accordance i
with Appendix J of 10 CFR 50, to ensure that all of TS valves were covered within the test.
This review showed that all valves were included within the test. Valve I A-A-101 was mislabeled as I A-A-107 in the procedure. This was discussed with plant engineering and l
subsequently resolved by a temporary procedure change.
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3.0 IST PROGRAM IMPLF31ENTATION The inspector's reviewed piping and instrument diagrams for the selected systems, as discussed in paragraph 1.0, to verify that all pumps and valves in the Code Class boundaries were included in the IST program. Further, IST records were reviewed for the selected components to verify that the test results were within specified limits, that testing occurred at the required frequency, and that all required tests were completed. The inspectors review consisted of a comparison of ASME Section XI code requirements with the program elements, implementation of Maine Yankee's relief requests as approved in NRC safety evaluation (April 1992), adequacy of implementing procedure and supporting engineering.
calculations, and past test result i
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The inspectors performed a walkdown of portions of the HPSI, LPSI, CS, SW and EFW systems. Installed gauges used for gathering IST pumps suction and discharge pressures were in calibration and properly reflected the calibration due dates. The location where the
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ultrasonic flow meters are mounted on the discharge pipes were adequately marked. No unacceptable conditions were observed.
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3.1 Service Water System J
The inspector reviewed the procedure "ECCS Routine Testing Service Water Pump Test", 3-
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1-2.9, to ensure that all of the valves in the IST program were incorporated in the licensee's
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i procedure. The inspector noted a procedural discrepancy, and discussed it with the Plant Engineering Department. Specifically, two check valves, in the IST program, SW-16 and SW-17, downstream of the service water header were not included in the IST procedure.
The licensee agreed to include these valves in the procedure.
l 3.2 High Pressure Coolant Injection, Low Pressure Coolant Injection and Residual IIcat Removal System
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l The inspector verified that the pumps and valves in the safety related portions of these systems were included in the Maine Yankee IST program. The systems were walked down by the inspectors and found to be in good order. There are procedures in place to control
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the testing of valves and pumps in accordance with ASME XI. The procedures give
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complete guidance to assess the results of each test.
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The inspectors reviewed completed tests and found that they were being performed on time and evaluated by the engineering representatives. All surveillance testing and the results were bag recorded in the surveillance log. The inspector reviewed the log from 1987 and
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found it to be complete. Where maintenance work requests were written, and rccorded in
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the surveillance log, the inspectors determined that appropriate corrective actions were taken
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to repair the identified concerns.
I The inspector concluded that appropr: ate ASME Code 1,2 and 3 pumps and valves with safety related functions were being tested in accordance with Maine Yankee Inservice Testing Program and Section IX of the ASME Code.
3.3 Review of Pump Test Data for the above Systems i
The inspector reviewed completed test results data sheets for the safeguards pumps. Test
l results were adequately documented and evaluated against established acceptance criteria.
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The test reference values and acceptance criteria were established in accordance with ASME Section XI. When the vibration data for LPSI pump 12B (Test of 3/2/92) were in the
" Alert" range, the licensee took appropriate actions by increasing the test frequency and closely monitoring vibrations. No discrepancies were identified.
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Pump test procedures were in conformance with ASME Section XI requirements. The
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inspector reviewed ECCS Operational Pump Flow and Check Valve Testing procedure No.
3.1.15.3, Revisiou 19, and ASME Section XI test procedure 3.17.6.6, used for completing safeguards pump flow testing in accordance with Technical Specifications (TS) 4.6. and Section XI. These procedures adequately addressed the necessary precautions, instrument calibrations, ranges, and installation to ensure that the requirements of ASME Section XI were adhered to.
3.4 Safety and Relief Valve Testing Most of the safety and relief valve testing is performed by certified vendors. _ The inspector reviewed the test data and certification test reports for the pressurizer and main steam safety-
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valves submitted to Maine Yankee by the vendors, and found them to be complete and in accordance with Section XI of ASME Code. The surveillance log also documents repairs and retests to pressurizer and main steam safety valves. The inspector found the surveillance log complete in the area of safety and relief valve testing.
3.5 Witnessing of Tests b
The inspector witnessed the testing of the feedwater regulatory bypass valves, primary component cooling water valves, and charging pump suction valves. The valves were tested
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in accordance with Maine Yankee procedure 3-1-20-3, "IST Valve Testing at Power". The objective of this procedure is to satisfy a portion of the Inservice Inspection Program per
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Maine Yankee's Technical Specifications, by testing the stroke times of these valves. In each test the stroke times were all met. The opemtors performing these tests were knowledgeable of their procedures, and performed their duties in a professional manner. The
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procedures for performing these tests were clear and concise. The completed data recorded
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in the procedures were reflective of the testing and were found to be satisfactory.
i 3.6 Post Maintenance Tests Procedure No. 3.17.8.1, ISI/IST Pump Tests for Work Performed Under Work Orders, Revision 3, provides information to assure that applicable tests are performed following work on a pump covered by the IST program. The inspector reviewed the procedure and found it
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adequate.
Procedure No. 3.17.8.2, IST Valve Tests for Work Orders, Revision 19, provides
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information to ensure that safeguards valves are properly tested after they have been repaired or replaced.
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3.7 Maine Yankee's Recent IST Submittal Maine Yankee has submitted their third interval plan for the Inservice Testing Program, which will cover December 22,1992 through December 28,2002. This inspection did not evaluate this submittal, as it was being evaluated by NRR.
4.0 CLOSUltE OF PREVIOUSLY OPENED ITEMS (Closed) Unresolved Item 50-309/90-23-01 During NRC inspection 50-309/90-23 of the HPSI system pumps relative to the issues discussed in NRC Bulletin 88-04, Potential Safety Related Pump loss, the following discrepancies were identified:
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In a letter to the NRC, dated January 2,1990, the licensee identified HPSI systems's worst case operation as the fill and vent mode at 64 gpm for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> a year.
However, in a letter to the pump's vendor, dated September 22,1988, the licensee l
requested evaluation for pump operation under this condition and stated that such operation would not exceed 1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> per year.
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The vendor recommended a minimum flow of 128 gpm for the HPSI pump in the l
Alternate Letdown mode. However, plant procedure 1-11-6, Chemical and Volume l
Control System Operation, Revision 27, limited flow in this mode to 106 gpm.
l In a letter dated May 15,1991, to the NRC, the licensee discussed their actions to resolve these discrepancies. Regarding the first discrepancy, the licensee requested further vendor evaluation based on the pumps operating at up to 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> a year since loop fills are likely to occur more than once a year. However, this mode of operation is shared among the 3 HPSI pumps to ensure that no single pump is operated for more than 1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> at a time in this
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mode. The vendor found this acceptable, provided this operation is shared by all pumps and that the pumps were periodically inspected. Regarding the second issue, the vendor indicated that pump monitoring and routine inspection should be performed to ensure that operation in the Alternate Ixtdown mode does not cause any excessive pump degradation.
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The licensee has established a periodic overhaul schedule for the HPSI pumps (every 5 years for cach pump) and revised operating procedure 1-11-6, Chemical and Volume Control System Operation (Revision 29), to ensure that during loop fill and vent, the HPSI pump being used is closely monitcred and is not operated beyond evaluated limits. However, based upon further discussion between the inspector and the licensee, the licensee implemented a temporary procedu.v. charge to add additional steps in the procedure to address pump monitoring when the alternate letdown was established.
This item is closed.
(Closed) Unresolved item 50-309/90-23-02 During the NRC inspection 50-309/90-23, the inspector observed that the adequacy of the common six inch minimum flow line for the low pressure safety injection (LPSI) and containment spray (CS) pumps was not documented. The inspector expressed concern over the ability of this line to handle the total minimum flow of 1500 gpm from the two LPSI pumps (800 gpm) and two CS pumps (700 gpm).
i The licensee performed an engineering evaluation (Calculation MYC-1374) to determine the effect of four pump operation on each pumps minimum flow rate and the flow through the common six inch line. The inspector reviewed the calculations and was satisfied that the
licensee had demonstrated the ability of the six inch line to provide adequate flow during simultaneous pump operation. The licensee also revised procedure 3.1.5.3, ECCS Operational Flow and Check Valve Testing to include collection of pumps suction pressures
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during testing for performance evaluation. The inspector had no other concerns.
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This item is closed.
(Closed) Unresolved item 50-309/90-23-03
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During the NRC inspection 50-309/90-23, the inspector identified a discrepancy with the minimum flow rate for the containment spray (CS) pumps. The licensee had stated in a
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letter dated July 7,1988, to the NRC that the minimum flow rate for each CS pump was 425 l
gpm. During the inspection, the inspector noted that the test flowrate in the licensee's
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procedure was 300 gpm. The licensee's evaluation of this discrepancy is documented in Technical Evaluation TE 63-91. Original 1968 specifications indicated that the minimum flow system should provide 425 gpm with a minimum flow valve and/or reduction in line
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size to control recirculation. An orifice was subsequently sized and installed to ensure minimum flow was above the recommended minimum but below the line full flow of 425 gpm. Test results indicate the available flow to be 300 gpm. Additionally, the pump vendor
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had indicated that a minimum flow of 200 gpm was sufficient for each pump. The licensee -
has revised containment spray specification MYS-601 (F.2) to reflect the actual vendor
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specified minimum flow rates for the CS pumps. The inspector concluded that the actual f
minimum flow available for the CS pumps is more than the minimum recommended flow and sufficient for pump protection during minimum flow operation. The discrepancy identified during the previous inspection in 1990 has been adequately resolved by the licensee.
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(Closed) Unresolved Item 50-309/90-23-04 During an inspection of the emergency feedwater (ERV) system in November 1990, the
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inspector noted that the EFW pumps minimum flow limitations were not strictly implemented within those specified by the pump vendor. The licensee had not adequately addressed the time limit of 15 minutes imposed on pump operation at minimum flow of 20 gpm. The
monthly surveillance test procedure did not address or limit the pumps' minimum flow test time (20 gpm) to 15 minutes.
,j Upon further communication with the pump vendor, the licensee decided to decrease the periodic overhaul time period of the ERV pumps to every 5 years. This was based on the
fact that since strict compliance with the recommended time limit of 15 minutes was not practical. Additionally, operating guidelines had been established and procedure changes made to discourage low flow operation. These actions, and the fact that overhaul results over the 16 years of pump operation had not indicated any excessive wear from mimmum flow operation, adequately address the concern.
This item is closed.
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5.0 CONCLUSIONS The Maine Yankee inservice test program was found to be soimd and complete with
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f significant program strengths. Scheduling is performed by the operations department and is computerized. This method of scheduling has been successful in implementing the tests without omissions. This system is backed up by the surveillance log, kept by engineering,
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which is capable of identifying a missed surveillance in a relatively short period of time.
Tracking and trending of valve and pump anomalies are very good. After each data
acquisition, data are entered into the surveillance book and reviewed by engineering l
personnel. Any valve or pump that falls into an alert range is more carefully monitored and the frequency of testing is increased. This trending increase lasts until the component is
repaired and retested or the anomaly is resolved.
l-No program weaknesses were identified.
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i 6.0 EXIT MEETING An exit meeting was conducted on July 2,1993, to discuss the findings with Mr. G Leitch and other members of your staff identified in Attachment 1. The licensee representative l
acknowledged the findings and had no additional comments.
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A'ITACIIMENT 1
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MAINE YANKEE B. Blackmore, Plant Manager L
J. Frothingham, Quality Programs Manager C. Giggey, Senior Engineer - PED
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l S. Ieclerc, QP Section Head l
G. I2 itch, Vice President Operations P. Mehlhorn, Senior Engineer - PED
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L Speed, Senior Reliability Engineer J. Weast, Licensing Engineer G. Whittier, Vice President Licensing & Engineering f
a US NUCLEAR REGULATORY COMMISSION
i K. Battige, Reactor Engineer Intern W. Olson, Maine Yankee R.esident Inspector
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Attachment 2 - Documents Reviewed Maine Yankee (MY) Inservice Testing Program (IST) - Dunber 9,1989 NRC Safety Evaluation for MY IST - April 28,1992 MY IST - January 28,1993 Procedures:
1-200-8, Operations Department Surveillance Schedule, Implementation and Records'.
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3.1.20.1, Containment Isolation Valve Testing at Power l
3.1.20.3, IST Valve Testing at Power 3.1.2.4, ECCS Routine Testing - HPSI Pump and Valve Testing
3.1.2.5, ECCS Routine Testing - LPSI Pump Test and Valve Test 3.1.2.3, ECCS Routine Testing - Valve Testing and Position Indication 3.1.20.2 & 3.1.20.4, Containment Isolation Valve Testing at Cold Shutdown 3.17.4, Type B&C leakage Testing 3.1.15.3, ECCS Operational Pump Flow and Check Valve Testing 67-20-1, Maintenance Self-Assessment Program 3.17.8.5, Review of Safeguards Valve Tests
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l Drawings for the following Systems l
Service Water HPSI LPSI CVCS RHR Maine Yankee Audits MY-92-06B - Audit of IST Program MY-924)1 - Audit of Operations and Technical Specifications 10 CFR ASME Section XI
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