IR 05000271/1993008
| ML20044E268 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/14/1993 |
| From: | Eugene Kelly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20044E262 | List: |
| References | |
| 50-271-93-08, 50-271-93-8, NUDOCS 9305240121 | |
| Download: ML20044E268 (24) | |
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a U.S. NUCLEAR REGULATORY COMMISSION
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REGION I
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Report No.
93-08 i
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l Docket No.
50-271
Licensee No.
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Licensee:
Vermont Yankee Nuclear Power Corporation
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RD 5, Box 169
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Ferry Road
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Brattleboro, VT 05301
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Vermont Yankee Nuclear Power Station Vernon, Vermont
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l Inspection Period:
March 14 - April 17,1993 Inspectors:
Harold Eichenholz, Senior Resident Inspector l
Paul W. Harris, Resident Inspector l
Neil S. Perry, Sr. Resident Inspector, Limerick
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Peter D. Drysdale, Senior Reactor Engineer
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Thomas J. Kenny, Senior Reactor Engineer
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Bren
. Whitacre, Reactor Engineer
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d Approved by:
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I Eugene M. Kelly Date
Chief, Reactor Projects Section 3A i
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Scope:
Station activities inspected this period included: plant operations; radiological
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controls; maintenance and surveillance; emergency preparedness; security;
engineering and technical support; and safety assessment and quality verificat on. The initiative selected for inspection was reactor water level i
instmmentation anomalies. Periodic inspections amounting to 26 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br /> of
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backshift, deep backshift and weekend activities were performed on March 16,
24, 26, 28, 29, April 6, 7, and 8,1993.
Interviews and discussions were conducted with members of Vermont Yankee
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management and staff as necessary to support this inspection.
Findings:
An overall assessment of performance during this period is summarized in the Executive Summary. The failure to perform a Technical Specification surveillance within the allowable time frame was not cited because of the minor safety significance and the corrective actions identified by the licensee were appropriate (Section 4.2.2).
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I 9305240121 930517 PDR ADOCK 05000271 G
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EXECUTIVE SUMMARY
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Vermont Yankee Nuclear Power Station l
Report No. 93-08 l
Plant Operations i
Power and shutdown operations were conducted in a safe'and well-controlled manner, i
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l Operator performance during the plant shutdown was professional. A good safety I
perspective was exhibited by plant management to shutdown the plant to repair a small l
l feedwater leak. Management response to reactor vessel water level instrumentation
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anomalies was well-focused and aggressive.
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Radiological Controls
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The implementation of the Dositec personnel radiation monitoring system in lieu of self-j
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reading pocket dosimeters was considered a good initiative to enhance dose assessment and j
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ALARA planning.
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Maintenance and Surveillance The "B" EDG mini-inspection at power was properly planned and appropriate management
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controls were implemented. Management's decision to secure from LCO maintenance on the l
"A" core spray system in order to better focus on fire penetration issues reflected a i
commitment to safe plant operations.
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t Enforcement discretion was granted by the NRC to allow'the licensee time to assess scram j
insertion time test data; subsequently, concerns regarding test methods, test results, data
evaluation, and parts procurement were identified by Vermont Yankee. This included the
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failure to shut down the reactor after the October 1992 testing indicated that one two-by-two l
array's Technical Specification scram insertion limit was not met.
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Vermont Yankee's involvement in a local Emergency Preparedness issue was positive and demonstrated a strong commitment in this area.
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I Security l
Vermont Yankee is assessing the effectiveness of the Employee Assistance Program due to
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recent unsuccessful rehabilitations.
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(EXECUTIVE SUhBIARY CONTIhTIED)
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Engineering and Technical Support l
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A review of the motor operator valve program identified improvements in program description, administration, and schedule.
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Safety Assessment and Quality Verification l
Decisions made this period were based on appropriate management reviews and a j
conservative safety perspective. Management decisions resulted, in part, due to good pre-
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planning. Use of Task Teams have been effective in conducting self-assessments and aiding
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in problem resolution.
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SUMMARY OF FACILITY ACTIVITIES
Vermont Yankee Nuclear Power Station (VY) continued safe plant operations this period.
On April 6, following 351 days of continuous power operations, VY reduced power to
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approximately 62 percent to conduct a control rod pattern change and single rod scram insertion time testing. Results of this testing indicated that VY was exceeding Technical l'
Specification (TS) requirements for notch position 46 core wide average and 2 x 2 array (Section 4.2.1). On April 7, at 10:00 p.m., enforcement discretion was granted for a period
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of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> to allow VY time to fully evaluate the surveillance data and any implications for unacceptable equipment performance. Subsequently, at 10:33 p.m. a plant shutdown was j
initiated to repair a pin-hole leak in the feedwater system (Section 2.3); this obviated the
need for the enforcement discretion.
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During this shutdown period, VY repaired the feedwater leak, conducted minor maintenance on balance of plant equipment, evaluated control rod drive performance and reactor water
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level instrumentation anomalies, continued inspection and repair of fire barrier penetration
seals, and further assessed the reliability of the emergency diesel generators. On April 16, following completion of the 10-day maintenance outage and Plant Operations Review i
Committee (PORC) review of the above issues, VY commenced reactor startup.
On March 16, Mr. J. Herron was promoted from his position as Operations Manager to that of Technical Services Superintendent. On April 8, Mr. L. Doane was promoted to Operations Manager from his previous position of Assistant Operations Manager.
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2.0 PLANT OPERATIONS (71707,93702,90712)
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l 2.1 Operational Safety Verification This inspection consisted of direct observation of facility activities, plant tours, and operability reviews of systems important to safety. The inspector verified that the facility i
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System Alienments and Plant Tours l
l The inspector observed plant operations during regular and backshift hours in the following areas:
Control Room Reactor Building Cable Spreading Room Turbine Building
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Switchgear Room Emergency Diesel Generator Rooms
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The inspector independently verified that control room logs were accurate, that correlation existed between similar instrument channels, and that emergency power sources were available. The inspector verified that safety tags and the tagout logs were properly implemented to assure system isolation and personnel safety "hltdowns performed on the residual heat removal, core spray, and high pressure coolan v m (HPCI) systems confirmed the operability and acceptable material condition of.d ny, elated pumps and valves. No leakage was observed on system instrument racks, motor operator actuators, or valve packing. Lighting and housekeeping were good. A walkdowm of the alternate shutdown panels and power supplies using plant procedure OP 3126, Rev. 9, "Shutdowm Using Alternate Shutdown Methods" identified no concerns. Tools needed for local venting control rod drive mechanisms and manual operation of the squib valves for emergency boron injection were properly inventoried, controlled, and marked. These tools are necessary to perform actions as called out by the Emergency Operating Procedures (EOPs).
Tours were also made in the drywell and the steam tunnel. In both areas, the main steam isolation, high pressure coolant system, and reactor core isolation cooling containment isolation valves were inspected. No deficiencies were observed with freedom of movement, valve stem grease, electrical connections, pipe snubbers, and spring canisters. Pipe insulation, floor grating, and lighting were properly installed. In the drywell, floor drains, sump areas, and the eight drywell to suppression chamber vent pipes were clear.
The inspector confirmed that firewatches stationed during the inspection and repair of Appendix R and Technical Specification fire barriers (Section 7.1) were cognizant of their duties, knowledgeable of the safety-significance of the areas compensated, and attentive.
Backshift inspections verified that the quality of the firewatches did not vary between shifts.
Control of flammable materials was in accordance with plant instructions and no fire hazard concerns were identified. The inspector observed rapid response to a fire alarm in the HPCI room that was caused by work associated with the repair of a fire barrier. Timely notification of the control room by the stationed firewatch contributed to prompt disposition of the alarm.
During the week of March 14, VY implemented compensatory measures in response to rising river water level due to a storm front entering the area. High winds and excessive snow fall / rain were expected. Control room operators frequently monitored river water levels and Protected Area tours were conducted to secure equipment and to monitor site conditions.
The actions were appropriate and in accordance with OP 3127, Rev. 4, " Natural Phenomena." During this period, river level was only marginally above normal and significantly below flood level. No plant damage was experienced.
Control Room Observations The conduct of plant operations was ir_ accordance with plant operating procedures.
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Operator response to alarms, control of reactor power both while operating and shutdowm, and coordination of maintenance and surveillance demonstrated effective command of facility
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operations. The inspector observed deep backshift control room operations on April 6 during the power reduction for the planned control rod sequence change. The control room atmosphere during control rod scram insertion testing was professional. Additional Operations Department personnel were on shift to assist in this testing. Communications between the auxiliary operators at the hydraulic control units and the control room operators were good. The Shift Supervisor exhibited good overall command and control.
l During the week of April 12 while the reactor was shutdown, the inspector performed
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sustained control room observations and concluded that attentive and responsive l
watchstanding was maintained. Shutdown procedures such as OP 0112, Rev.10, " Shutdown Operations" and OP 2124, Rev. 29, " Residual Heat Removal System" were followed, and l
plant evolutions (surveillances, maintenance and testing) were planned and properly authorized. Equipment status logs were accurate.
l 2.2 Engineemd Safety Featum System Walkdown - Standby Gas Tmatment System An engineered safety feature system walkdown was performed of the accessible portions of the standby gas treatment system components to verify operability. The inspector verified that the system lineup procedure matched the piping and instrument drawing, and the actual system configuration. Drawing G191238, Reactor Building HVAC, Rev. 22, and procedure OP 2117, Rev.13, " Standby Gas Treatment" were used for the lineup verification.
Procedure OP 4117, Rev.17, " Standby Gas Treatment System Surveillance" was used to verify that the appropriate TS requirements were met.
l The inspector concluded that the standby gas system was properly aligned for operability as j
required, and no equipment conditions existed that might degrade overall performance. No discrepancies were identified.
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l 2.3 Plant Shutdown for Feedwater Line Leak Repair On April 6, at 10:33 p.m., while at approximately 62 percent rated power VY commenced a l
plant shutdown to repair a small feedwater leak in the common discharge piping of the
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feedwater pumps. Plant operators identified the 0.5 to 1.0 gpm leak streaming from the
lagging of the 24-inch feedwater pump discharge header between the "B" and "C" main
feedwater pumps. No plant equipment damage and no operational transient occurred.
Vermont Yankee detern'ined that the leak was caused by porosity in a weld sealing a plugged instrument test connection. A Yankee Nuclear Services Division (YNSD) metallurgist observed the excavation of the weld and verified that the hole transversed the pipe wall (1.812 i 12 % inch nominal). A non-destructive magnetic particle test confirmed this observation. No galvanic or excessive general corrosion was observed. The inspector independently assessed the condition of the plug and instfument tap.
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1 The pipe integrity and repair method were irdependently verified by YNSD engineering.
Ultrasonic testing of base material in the vicinity of the plug (360 degree circumferentially and approximately 3 linear feet) verified that the base material was sound and well within nominal thickness tolerances. Vermont Yankee has previously assessed this section of piping in their erosion / corrosion program and evaluation by CHECKMATE concluded that this area is not susceptible to erosion / corrosion due to low fluid velocity and turbulence. The ultrasonic measurements confirmed the CHECKMATE results.
Upon identification of the leak, actions were taken to place the area off-limits to personnel.
No assessments of the leak were allowed until the piping'was depressurized. Plant personnel and management exhibited an excellent safety perspective to both promptly place the area off-limits to personnel and shutdown down the plant to repair this leak, and to control initial investigations.
2.4 Reactor Water Level Instrumentation Anomalies On April 6, during the plant shutdown, control room operators observed reactor water level
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instrumentation spiking on control room panel level instrumentation. Reactor vessel water level was approximately 174 inches, reactor pressure 0 psig, and the plant was on shutdown cooling. Two types of level spiking were observed: periodic notching - I to 2 inch high level spikes occurring every 15 to 30 minutes; and, rapid and successive spiking. This latter
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spiking lasted for approximately 15 minutes and appeared to occur at random. The individual spikes were 8 to 12 inches in height and lasted between 1.3 and 1.8 minutes each.
All spiking was observed on non safety-related feedwater level control and transient water level instrumentation (LT-2-3-67, 68, and LT-6-52A/B) and was more prevalent on the "A" instruments. No persistent water level mismatches were observed.
l In response to Generic Letter 92-04, VY monitored and recorded reactor level, pressure, and temperature indication for both safety and non safety-related systems during the plant shutdown. A significant Corrective Action Report (CAR 93-010) was developed to document VY's investigation of the level notching event. A multi-disciplined task team evaluated the data and determined that the spiking was due to non-condensable gases in the instrument lines and not in the reactor vessel level reference legs. This was based, in part, by the lack of level spiking on the safety-related instruments which share the common reference and variable legs of the 'A" and "B" reactor vessel level systems. Vermont Yankee stated that the piping configuration of the affected instruments (3/8 inch tubing and lack of constant head chambers at the instrument racks) contributed to level spiking phenomena. Vermont Yankee determined that the level anomalies occurred at a much lower frequency and pressure (0 psig) than at other plants. Walkdowns of level instrumentation identified a very small leak
i on an instrument tube fitting and leakage rate monitoring was implemented. Additionally, VY noted that the anomalous behavior only occurred on level instrumentation that were calibrated using air, without the use of constant head chambers. In this case, VY relies on sufficient venting and t,ackfilling to remove all entrapped air.
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Prior to plant startup on April 16, the sensing lines for the four subject instruments were backflushed to remove non-condensable gases. No level anomalies were observed during plant startup or power operations. Corrective actions, as specified in CAR 92-010, included instrument rack inspections on a monthly basis, modification of the affected instrument lines with larger diameter piping, and modification of the level instrument calibration procedure to require " wet calibration."
Plant management required the reactor water level spiking evaluation to be completed and reviewed by PORC prior to plant startup. Corrective actions have been assigned in the VY Commitment Tracking System. Operators have been trained on recent industry experience l
i regarding this issue and were sensitive to level anomalies. Plant procedures address this i
issue. The inspector determined that plant management's evaluation and corrective actions l
were appropriate.
3.0 RADIOLOGICAL CONTROLS (71707)
Inspectors routinely observed and reviewed radiological controls and practices during plant tours. The inspectors observed that posting of contaminated, high airborne radiation, and high radiation areas were in accordance with plant instructions. High radiation doors were properly maintained and equipment and personnel were properly surveyed prior to exit from the radiation control area. Plant workers were observed to be cognizant of posting requirements and maintained good housekeeping.
3.1 Personnel Radiation Monitoring This period, VY implemented a new computerized radiation monitoring program. This system uses Dositec personnel radiation monitoring devices and interfaces with the plant health physicist computer system for radiation work order implementation and personnel dose tracking. Immediate dose assessment, prompt extension of personnel exposure limits during exigent conditions, and improvements in ALARA planning are expected benefits to be l
derived by system implementation. Plant personnel were knowledgeable of the cumulative dose and dose rate features of the new radiation monitoring devices. The implementation of
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this system is considered a good initiative.
3.2 Containment Venting Radiological Survey
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In accordance with TS 4.8.L, the primary containment atmosphere was sampled prior to venting via the reactor building ventilation system to assure that release limits are not exceeded. The survey results indicated that the total fission gas activity to be greater than a l
factor of 100 less than the TS lower limit of detection (1x10-4 pCi/ml) and less than 1 MPC (maximum permissible concentration). The inspector verified that all principle gamma emitters, as identified in the TS, were analyzed and that the results were less than the lower l
limit of detection.
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4.0 MAINTENANCE AND SURVEILLANCE (62703,61726,92700)
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4.1 Maintenance
'Re inspector observed selected maintenance on safety-related equipment to determine whether these activities were effectively conducted in accordance with TS, using approved procedures, safe tagout practices and appropriate industry codes and standards.
4.1.1 Emergency Diesel Generator Maintenance LCO Maintenance Plan Review On a staggered basis, VY conducts regularly scheduled preventive naintenance (PM) on each emergency diesel generator (EDG) every 18 months in accordance with vendor (Fairbanks-Morse of Colt Industries) recommendations. The 18-month inspection for the "B" EDG was last performed in October 1991 and was due in March 1993. Vermont Yankee retracted it's licensing amendment request for a 14-day LCO period to conduct cylinder liner replacements during the 18-month overhaul. Therefore, VY plans to replace engine cylinder liners and conduct engine overhaul activity during Refueling Outage XVII (August 1993).
In order to prevent two intrusive disassemblies of the "B" engine, VY requested and received Fairbanks-Morse concurrence to perform a mini-inspection in lieu of the complete 18-month preventive maintenance (PM) inspection in March 1993, provided that the balance of the inspections be performed during the outage. The complete inspection would be deferred based on: (1) a vendor review of diesel operation data to identify anomalies with engine performance, and (2) the satisfactory completion of a mini-inspection to determine the physical condition of power train components. A similar PM extension and mini-inspection were last performed in November 1989.
On March 25, the NRC held a conference call with VY to discuss the proposed diesel mini-inspection. Discussions focused on the maintenance planned, relative increases in risk, expected benefits resulting from the maintenance, and the operational necessity of performing the inspection. Concern regarding adverse weather conditions and the potential for human error during the maintenance were also discussed. Vermont Yankee cited previous experience with this type of inspection, inconsequential increases in core damage frequency as a result of the diesel being out of service for 40 percent of the 7-day limiting condition for operation (LCO) limit, increased management oversight, compliance with vendor recommendations, and various contingency plans and actions as part of their basis for justification for performing this maintenance at power. Vermont Yankee indicated that the mini-inspection is an important element in assuring that it is unlikely that a failure of power train components will occur prior to the conduct of the more extensive overhaul during the up-coming refueling outage. Additional justifications for conducting LCO maintenance l
included: (1) performing PMs on the EDG generator; (2) calibrating and functionally testing protective relays and instruments; (3) preventing corrective maintenance on generator I
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pedestal hold-down bolts and fuel oil transfer system; and (4) installing seismic upgrades in
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control and electrical distribution panels. On March 26, the State of Vermont received a brief by NRC management regarding this conference call.
Vermont Yankee implemented contingency plans to assure that sufficient plant engineering and maintenance personnel, and technical support from the diesel vendor were available onsite for the maintenance (24-hour coverage was provided). Coordination with Stores and Security Departments was established to prevent delays associated with parts and access to the diesel room. High risk surveillances and significant maintenance on other safety-related systems were schedu!ed outside of the LCO period. Appropriate management instructions were provided to control room operators regarding the actions required prior to the removal of the diesel from service. These included, in part, alternate testing of the "A" EDG and emergency core cooling systems, and verification that the alternate emergency Vernon Tie was available and reliable.
l Based on a review of the LCO Maintenance Plan and discussiens with plant management, the NRC concluded an acceptable level of safety would be maintained during VY's discretionary entry into the TS LCO action statement for the performance of maintenance on the "B" EDG l
while at power. Appropriate management controls were implemented.
Mini-Inspection On March 29, at 3:10 a.m., VY commenced the mini-inspection on the "B" EDG and restored the engine to operation on March 31. The scope of this 59-hour mini-inspection focused on power train components such as camshaft bearings and cams, main and l
connecting rod bearings, the blower and piston floating bushings, lube oil water pump and blower gears, and tiie vertical drive mechanism. These inspections provided assurance that, mecbnically, the engine would perform its design function. A 50 psig pressure test was per" tmed to verify the " cold" integrity of the jacket cooling system as well as portions of the cylinder liners. The licensee used the Fairbanks-Morse technical manual and OP 5223, Rev.12, " Emergency Diesel Generator Maintenance" for the inspections. Preventive maintenance on fuel injectors, crank timing, and cylinder liners was not performed nor required by the vendor during this inspection.
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Preventive maintenance on the electrical systems was in accordance with OP 5225, Rev. 7, l
" Emergency Diesel Generator Electrical Maintenance." This maintenance included, in part; inspections of collector and slip rings, lube oil, cooling, pre-lube pumps, and governor linkages; as-found meggar testing of transformers, voltage regulators, and generator windings; and testing of air start, time delay, governor shutdown, breaker trips, and engine run relays. The complete 18-month electrical PM was performed with the exception of DC j
high potential testing of the generator stator.
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The inspector conducted normal and backshift inspections to determine the adequacy of the maintenance performed. Quality control inspections performed by VY on the blower, EDG
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l generator mounting plates, vertical drive spring coupling, and collector rings were observed by the inspector; as-found measurements were acceptable. Quality control hold points were i
utilized and documentation of as-found conditions was adequate. Additional NRC review i
pertaining to VY's disposition of as-found conditions will be documented in NRC Inspection Report 93-10. The inspector attended a shift brief for the backshift maintenance crew on March 29 and concluded that idendfication of maintenance priorities, information discussed, and participation of the maintenance crew contributed towards quality maintenance.
l The inspector noted improvements in the maintenance procedures used. These improvements consisted of: cross references between the vendor manuals and service information letters to the procedure; inclusion of the 4.5 - 5 year vendor PM recommendations into the procedure; signature and date sign-offs for specific maintenance performed and equipment calibrations; and increased detail in instructions for vacuum ejector assembly, scaffolding, and equipment walkdowns. Some of the procedure enhancements were made regarding post-maintenance
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operability walkdowns and bolting.
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At the completion of the mini-inspection, VY evaluated the results and concluded that
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l reliability of the "B" EDG can be reasonably assured until the balance ofinspections can be performed durino, the Refueling Outage (Fairbanks-Morse concurred with this assessment).
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Measurements were within tolerances, inspections identified no significant deficiencies, and the post-maintenance testing verified the satisfactory completion of maintenance performed.
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The inspector concluded that the maintenance was well-planned and personnel were l
knowledgeable of the maintenance performed.
Soeed Switch As documented in NRC Inspection Report 93-04, the licensee failed to implement adequate written procedures to control the surveillance testing of this switch and as a result, procedural revisions were implemented. Currently, the 810 rpm setting of the speed switch is being tested on a monthly basis to establish a data base for the evaluation of drift and repeatability. The normal calibration frequency was established as cyclic, similar to that of the generator voltage relay.
l Prior to removing the "B" EDG from service, the "A" core spray (CS) system was returned
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to operation (Section 4.1.2) and TS-required alternative testing was performed on the "A" EDG. During this test, the centrifugal speed switch on the "A" engine was checked, and actuated just below the 810-855 rpm acceptance band. A new switch was withdrawn from stock, bench tested, and installed. On March 28, the post-maintenance testing was performed and VY identified that the new switch had a different internal wiring configuration l
than the original. Both switches were manufactured by Synchro-Start Product, Inc.,
j procured through Fairbanks-Morse, and had the same model number (GO-3A). The
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technical information provided with the new switch correctly represented the wiring configuration within the switch. Vermont Yankee acknowledged that receipt inspection and bench testing failed to identify this discrepancy and that information existed in the VY technical manual (VYEM 0107) which described the different wiring configuration. A non-conformance report was issued to determine root cause and corrective action.
The inspector observed the April operabiliiy testing on both diesels, and switch testing on the
'B" engine. Adequate procedures were in use despite VY's failure to identify the above discrepancy, and the bench-tested configuration was similar to that installed. The licensee identified that the switch setting was relatively sensitive to acceleration and improved the bench test apparatus and test procedure to better control speed and ramp rate and more closely represent field conditions. Prior to these improvements, speed fluctuations made the acquisition of test data difficult. On one occasion, the test crew was unable to perform a switch test due to coordination difficulties; the test was satisfactory completed by the next shift. In addition, a number of retests were performed to verify repeatability of as-found/as-left values. The inspector identified no concerns with regard to test control and considered that the surveillance testing was generally well coordinated. Good management oversight was provided during the surveillances, and timely operability determinations and maintenance
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decisions were made. A commitment item was assigned for engineering review of switch repeatability concerns.
Vermont Yankee has established an acceptance band of 810 to 855 rpm for ST relay permissive and determined that no operability concern exists if the setting was found below 810 rpm, because: (1) actual engine speed is dependent on the diesel governor settings, not on the speed switch; and, (2) the engine will reach rated speed / frequency prior to achieving rated voltage; therefore, closure of the generator output breaker would be dependent on the time it takes to reach rated voltage. This was verified by both video recording of diesel
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indications and a review of recent integrated emergency core cooling system test results.
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However, if the switch was set significantly above 855 rpm (i.e. approaching 900 rpm),
engine operability would be questionable. In this case, should the output breaker shut when
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the governor is reducing engine speed to mitigate the initial speed overshoot (above 900 rpm)
during engine start, bus voltage and frequency may dip below rated values due to slow voltage regulator and governor response characteristics.
Regarding the centrifugal speed switch input to the engine run relay permissive, VY has yet to establish and justify an acceptance band for the 200 rpm switch setting. The two concerns are: (1) if the setpoint is too low field flash may occur without the engine on combustion (i.e. during air start), and (2) if the setpoint is too high the delay in field flash may result in the diesel not obtaining rated voltage (and speed) within the TS-required 13 seconds.
These switch setting concerns were discussed with a VY representative and an NRC specialist inspector. Further NRC review is documented in NRC Inspection Report 93-1.
4.1.2 LCO Maintenance
"A" Core Spray System j
During March 24-25, VY entered the "A" CS system 7-day LCO to perform maintenance.
Activities inch'ded motor operator valve performance testing (V14-7A), calibration of flow and pressure switches, and repair of a differential pressure instrument potentiometer and a
"A" CS pump breaker swivel wheel. The original scope of this maintenance was slated for 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> (38 percent of the TS LCO) and was to include additional valve testing and pump motor PM (V14-11A and 12A), however, VY terminated.the maintenance and retumed the i
system to operation due to concerns regarding fire penetration seals.
The availability and material condition of both CS systems remains very good and the maintenance performed provided further assurance that instruments are within calibration and motor operated valves will operate properly. Vermont Yankee provided, consistent with established NRC guidance, proper justification that the maintenance provided a net safety benefit. Management's decision to promptly and safely secure from the maintenance to better focus on the fire penetration issue reflected prudent operations.
4.1.3 Intermediate Range Monitor Maintenance
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Intermediate range monitor (IRM) channels "E" and "F" became inoperable during the startup from the last refueling outage in April 1992. Work Orders (WOs) 92-H892 and 92-04880 were issued for the IRMs, respectively. Following the April 6,1992 plant shutdown, both channels were repaired. The IRM channel "E" was inoperable because a detector connector had come apart, apparently because a securing nut was insufficiently tightened.
The IRM channel "F" failure was attributed to end-of-life. Repairs wem followed by appropriate post-maintenance testing. On April 8 and 9,1993, IRM channels "E" and "F" were retumed to service and performed correctly during the subsequent startup.
Documentation on the WOs of work requirements and repairs performed was adequate.
4.2 Surveillance The inspector reviewed procedures, witnessed in-progress surveillance testing, and reviewed completed surveillance packages. The surveillances which follow were reviewed and were
found effective with respect to meeting the safety objectives of the surveillance program.
The inspector observed that all tests were performed by qualified and knowledgeable
personnel, and in accordance with TS and approved procedures.
4.2.1 Control Rod Scram Time Testing During the rod pattern exchange on April 6, VY performed control rod semm time testing for half of the control rods (89 total). Results indicated that the average core wide scram insertion time for rod notch position 48 to 46 exceeded the TS limit (0.358 secs) by 0.011
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seconds. In addition, seven of 68 two-by-two rod arrays also exceeded the TS time limit (0.379 secondr) by 0.001 to 0.026 seconds. No inoperable rods were identified and the drop out times for notch positions 36, 26, and 06 were within specification.
Prior to the testing, VY had received a YNSD engineering evaluation which concluded that reactor safety limits would not be impacted until the rod notch 46 scram insertion time
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approached 0.5 seconds. This evaluation was based on actual plant performance data for Cycle XVI, whereas the TS values were based on plant performance data obtained prior to
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1981. The transient, turbine stop valve closure with failure of the turbine bypass system,
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was used as the limiting core transient.
Because the as-found conditions were contrary to TS 3.3.C.l.1 and 3.3.C.I.2, and would have required a plant shutdown, a VY verbal request was made to the NRC at 10:00 p.m. on April 6 for enforcement discretion. Verbal enforcement discretion for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> was granted by the NRC, in which VY was to propose a duration for the final enforcement discretion and an evaluation of the potential cause(s) for the increase in scram insertion times. Subsequent to the verbal NRC notice, a plant shutdown for repair of a feedwater pipe leak occurred. A
letter on April 7 was submitted by VY to document the need for the enforcement discretion.
On April 9, the NRC issued the Notice of Enforcement Discretion. Although the plant shutdown obviated the need for the entire 48-hour period and was therefore terminated, the NRC specified that further enforcement discretion would not be considered until VY
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demonstrates that the slower scram insertion times would not constitute a significant degradation of the control rod drive system.
Vermont Yankee implemented three task teams and received onsite assistance ffom General Electric (GE) and ASCO Corp. to determine root cause for the slow scram insertion times, to j
identify corrective actions to prevent recurrence, and to review scram time test methods and i
data evaluation techniques. On April 10, VY preliminarily determined that the slow scram times were attributed to slow respense of the scram solenoid pilot valves (SSPV) on the hydraulic control units and not a result of contml rod drive performance. General Electric is independently eva'ur. ting the performance of the pilot valves. The SSPVs are manufactured
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by ASCO (model HVA90-405-2A) and are supplied to VY through GE.
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J Although the root cause of the slow scram insertion times was not knowTi prior to reactor startup, VY had reasonable assurance that the deficient component (SSPV) was identified and that the corrective actions implemented would assure that the control rod system would operate within license limits. Some of the corrective actions VY implemented included:
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measurements of SSPV critical dimensions, performance of SSPV testing, replacement of all SSPV internals, and scram time testing at both cold hydrostatic and hot operating pressures.
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The results of the testing indicated that the improvement in scram insertion times was directly related to the replacement of the SSPV internals.
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Prior to the performance of scram insertion time testing on April 6, VY identified that the TS limits may be challenged during the April 6 test. This was based on the insertion times obtained at the beginning of Cycle XVI during cold hydrostatic testing (0.344 seconds) and during scram testing performed during a rod pattern exchange in October 1992 (0.348 seconds). VY informed the resident inspectors of this information on April 2. Further, VY identified on April 12 that the conclusions reached following the testing in October 1992 may have been incorrect in that one two-by-two rod array apparently exceeded the TS limit and a plant shutdown was not conducted in accordance with plant Technical Specifications. A 10 CFR 50.72 ENS notification was made for this determination.
Concerns agarWng this event including: (1) the apparent failure of VY to identify that one two-by-two array exceeded the TS limit in October 1992, (2) the applicability of the industry notices to the problems identified at VY, and (3) the adequacy of VY root cause determinations and corrective actions will be reviewed by NRC Inspection 50-271/93-09.
4.2.2 Missed Technical Specification Suneillance On January 4, VY identified that a TS-required monthly surveillance test on the steam jet air ejector (SJAE) radiation monitor was not performed within the alloveable time of 38 days (1.25 times 30). The surveillance was successfully completed at the time of discovery. The licensee determined the root cause to be inadequate training of the department test coordinator with a contributing cause being an inadequate surveillance testing procedure.
Vermont Yankee will revise the applicable procedure to clarify testing requirements and conduct training for department test coordinators. The licensec issued License Event Report 93-02, " Missed Technical Specification Surveillance, Source Check of Steam Jet Air Ejector Process Monitor Due to Inadcquate Training" describing this event.
The inspector considered the corrective actions appropriate. The results of the surveillance, performed one day late, were within specification and confirmed that the SJAE monitors would have operated as designed. The inspector conducted interviews with department test coordinators to verify that surveillance test program requirements and this event were understood. The cause of this event was inadequate training. The implementation of the computerized surveillance tracking program is considered appropriate and should eliminate potential human errors associated with manual surveillance scheduling. This violation involving the failure to perform a surveillance meets the criteria for enforcement discretion of Section VII of the NRC's Enforcement Policy and will not be cited.
4.2.3 Surveillances Obsen'ed The inspector reviewed the following procedures, witness'ed in-progress surveillance testing, and reviewed surveillance results. All tests were performed by qualified and knowledgeable personnel and in accordance with approved procedures and TS.
OP 4126, Rev. 29, " Diesel Generator Surveillance"
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OP 4210, Rev. 20, " Maintenance and Surveillance of Lead Acid Storage Batteries" OP 4628, Rev. O, " Sampling and Analysis of the Residual Heat Removal Heat Exchanger" OP 4514, Rev. 4, " Sampling and Analysis of Containment Environment" 5.0 EMERGENCY PREPAREDNESS (71707)
5.1 Emergency Drill
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On March 16, plant personnel conducted a practice emergency drill. This drill was intended as a practice for the annual emergency exercise. The inspector observed portions of the drill, attended the post-drill critique in the technical support center, and concluded that the drill adequately met the goal of providing plant personnel with training for the annual exercise and potential plant events. In particular, the inspector noted that the critique was comprehensive with good comments and recommendations from the players and observers.
The inspector identified no deficiencies.
5.2 Local Emergency Operations Center - Communication Equipment Concerns local officials in the Town of Hinsdale, NH, which is within the 10-mile Emergency Planning Zone, registered concerns about the reliability of communications equipment that is required to be used in the event of a plant emergency. Emergency Preparedness (EP)
representatives from VY and the State of New Hampshire's Office of Emergency Management met with Hinsdale, NH officials on April 5 to discuss the issue. Vermont Yankee determined that the replacement of aging communications equipment was appropriate and facilitated the acquisition of new equipment.
The inspector noted that VY provided timely resolution o'f the local EP issues. This resolution is evidence of a strong commitment to assuring effective emergency preparedness.
6.0 SECURITY (71707,92700,93702)
The inspector verified that security conditions met regulatory requirements and the physical security plan. The plant physical security was inspected during regular and backshift hours to verify that controls were in accordance with the security plan and approved procedures.
Officers properly responded to security perimeter and other equipment deficiencies and complied with procedures. Security force personnel performed their duties in an alert manner.
6.1 Fitness For Duty - Positive Test Result Oi. April 7, a VY Maintenance Department Supervisor was found to have a positive alcohol test during random Fitness-For-Duty (FFD) testing. The individual was escorted offsite and his access was immediately terminated. The results of the individual's request for a blood test at the local hospital also indicated positive and were communicated to VY on April.
The individual had a prior positive test (for cause) on April 10,1992 and was receiving treatment in VY's Employee Assistance Program (EAP). In accordance with VY's FFD Program, the current positive test for alcohol resulted in the individual's site access being permanently revoked and employment terminated. The NRC's review of the April 10,1992 event is documented in Section 6.2 or NRC Inspection Report 92-06.
Vermont Yankee's has had two EAP referrals that ultimately turned out to be unsuccessful rehabilitations. Based upon this condition, VY is conducting an assessment of the EAP to ensure that their employees, and members of their families, will be provided with effective services.
The inspector verified that 10 CFR 26.73 reporting requirements for this event were accomplished and concluded VY's voluntary action to ensure the effectiveness of the EAP was evidence of a very good commitment to their FFD Program.
6.2 Devitalizing a Room for Planned Maintenance Vermont Yankee Security devitalized a room to support unfettered au:ess during planned maintenance. Appropriate orders were written to detail the events and conditions necessary to assure that the access control was no longer required. Security walkdowns and checks were performed to verify that the room was properly restored to a vital area. Appropriate management approvals were obtained for this activity.
7.0 ENGINEERING AND TECIINICAL SUPPORT (71707,62703)
7.1 (Closed) Unresolved Item 92-24-01: Degraded Fire Barrier Penetration Vermont Yankee aggressively pursued resolution of fire barrier issues by the conduct of an enhanced surveillance on all barriers and penetrations, and the repair or upgrading of the
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l barriers for any deficiencies identified. On April 14, all 77 listed barriers (includes 43 TS, 10 Appendix R safe shutdown areas, and 24 Appendix A to BTP 9.5-1) had the surveillances completed. This compares to approximately the 18 barriers that had been surveilled as of the start of the inspection period. To date, approximately 813 items were identified that represented issues rcquiring rework or resolution as to the acceptability of the as-found condition. The assigned Task Force continued to meet regularly, provide management i
i oversight, and effective program control over timeliness, quality, and technical resolution of identified issues.
Regarding the performance of the Task Force, it was their collective judgement on March 24 that the number of deficiencies identified to date would conservatively suggest that each additional barrier inspected would identify further deficiencies requiring operability determinations. Given this lack of confidence about the existing barrier conditions, a decision was made to post firewatches on the remaining TS and Appendix R barriers that i
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j were neither inspected nor repaired. The five existing firewatches increased to seventeen.
j The inspector noted that the identification of resources and placement in the field of the
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added personnel was performed well.
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Another issue that was identified involved the acceptability of the existing penetration desigrs
to meet Appendix R of 10 CFR Part 50, for unsealed conduits in duct banks located between the east and west switchgear room floors. A Potential Reportable Occurrence Repon was
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i issued on April 5, and although at the time a conservative NRC Emergency Notification System call was made pursuant to 10 CFR 50.72, a subsequent reportability determination e
indicated the issue was not reportable. However, following questioning by both the inspector
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and VY's Engineering Director, additional engineering evaluations were conducted that i
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indicated some ducts warrant the addition of fire barriers to enhance the existing Appendix R
protection scheme. Until the issues could be fully developed and resolved, VY had the manhole covers removed to facilitate inspection as part of the firewatch detail for both
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l switchgear rooms. This made the installed carbon dioxide suppression systems inoperable l
due to the potential for dilution. Iexan covers were devised as a creative solution to meeting fire prevention and protection requirements. Vermont Yankee has demonstrated good safety
l perspective and technical expertise regarding this issue.
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NRC Inspection Report 93-05, which evaluated VY's pro' ram for correcting the self-l g
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identified fire barrier penetration seal deficiencies was issued on April 1. An Enforcement l
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Conference occurred on April 21. The NRC will resolve open fire barrier issues during its
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review of NRC Inspection Report 93-05 items.
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7.2 High Energy Line Break Mitigation
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During normal full power operations on March 18, the reactor building 232' elevation
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stairwell door leading to the reactor core isolation cooling (RCIC) pump room was blocked i
i open to allow the passage of an air line. This action was approved by the shift supervisor in
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support of fire barrier penetration seal repair work. According to VY's Environmental
i Qualification (EQ) Plan: (1) the door is structural equipment required to be closed except i
during passage; (2) this class of equipment shall be in the required status to assure j
maintenance of required environmeital conditions assumed prior to, during and following
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postulated design basis accidents; and (3) if this equipment is found not to be in compliance i
with the required status, the discrepancy shall be corrected within 30 days. Shortly following j
l the inspector's questioning of the acceptability of the conditions, the air line was removed
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The action of the operating shift was done without consultation with the engineering
organization, which provides EQ Plan and issue oversight. Following discussions with the cognizant VY engineer responsible for EQ issue resolution, the inspector was provided
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documentation specifying the relationship between the RCIC 232' elevation equipment space,
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a postulated high energy line break (HELB) of the RCIC or the high pressure coolant
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injection systems, and the mitigation provided by the stairwell enclosure and door in
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discharge volume analog cabinets. Engineering Design Change No.84-104, RCIC System HELB Mitigation, added a sign to the installed door stating, " CAUTION: KEEP DOOR CLOSED DURING PLANT OPERATION," in order to insure that the door will not be physically tied or wedged open. Voluntary removal of EQ required protective features from service by VY has been documented in NRC Inspection Reports 92-21 and 92-25, and is being reviewed by the NRC under Unresolved Item 92-21-03. Resolution of NRC concerns in this area are being addressed by VY's revision of their EQ Plan and the Basis for Maintaining Operability (BMO) Guideline, in which the prescriptive steps within the EQ Plan would be relocated to the BMO Guideline. According to VY's Engineering Director, the EQ Plan would provide the overall EQ philosophy and identify departmental responsibilities while, the BMO will provide specific details as to how EQ should be considered in the l
determination of structure, system or component operability. For the specific issue, the l
RCIC 232' elevation doorway being held open to allow hose passage would need to be l
addressed via the BMO process to determine if there was an operability impact on any of the affected equipment.
Program documents have been marked up to reflect the above described changes and await finalization and issuance. The NRC will review these documents to ensure that they properly reflect the guidance of Generic Letters 88-07 and 91-18. The Engineering Director informed the inspector that other, more highly reactive issues have precluded the VY engineering
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organization from completing efforts in this area.
l 7.3 Motor Operated Valve Testing
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The inspector reviewed the status of the VY's motor operated valve (MOV) program
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ceveloped in response to NRC Generic Letter (GL) 89-10. The MOV program was initially evaluated in NRC Inspection Report 91-80. This inspection identified nine separate commitments and followup actions for further program development in the areas of MOV program scope and administration, documentation of design basis reviews, diagnostic test l
equipment inaccuracy, MOV maintenance, performance monitoring and trending, and addition of progrran requirements to specify dynamic testing of MOVs practicable to test.
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The original rine commitments in these areas were later expanded by VY into 31 specific action items.
l Vermont Yankee has made notable improvements in the areas of program description,
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administration, and schedule. Three MOV program documents outline the Program Plan, the Testing Program Plan, and the Project Milestone Schedule. These actions complete three of VY's commitments to establish criteria for including MOVs in the GL 89-10 program and to
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establish administrative and responsibilities in all functional areas described by the GL.
Also, documentation of MOV maintenance and vendor information was improved by l
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d implementation of the Maintenance Planning and Control System, a computerized database and work tracking system. The remaining seven commitments are still in progress and are t
tracked under 15 separate action items that are scheduled for completion by Spring 1995.
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j On February 5, VY submitted a letter to the NRC summarizing the present status and i
schedule of the MOV program and indicating that the previous program completion date will
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i be extended to the outage in Spring 1995 in order to complete modifications required for plant systems and GL 89-10 MOVs. Vermont Yankee also indicated that all design basis (
reviews will be completed by December 31,1994.
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The VY letter was being reviewed by the NRC at the time of this inspection. The results of j
the NRC review will be communicated to VY in a separate correspondence.
8.0 SAFETY ASSESSMENT AND QUALITY VERIFICATION (40500,90712, 90713, 92700)
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8.1 Management Assessment of Facility Operations
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On a number of occasions during this period, the inspector observed that plant management exhibited conservatism when the potential for safety significance existed, as exemplified by their decision to shutdown the plant to repair a small feedwater leak. In addition, timely implementation of multi-disciplined task team evaluations of control rod drive performance and reactor vessel water level instrumentation anomalies contributed to management's decision to commence the reactor startup on April 16. These issues were properly prioritized
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based on the safety significance of the issue involved, as indicated by the decision to secure from the "A" CS LCO maintenance to better focus on fire protection issues. Prior planning
and appropriate management reviews were evident during the mini-inspection of the "B" EDG and observations related to reactor vessel wat r level instrumentation perforraance.
8.2 Periodic and Special Reports
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The plant submitted the followmg penodic and special repons which were reviewed for accuracy and the adequacy of the evaluation:
e Monthly Statistical Report for March 1993 e
Vermont Yankee 1992 Annual Operating Report 8.3 Licensee Event Reports
The inspector reviewed the following Licensee Event Reports and concluded that for each report: (1) the repon was submitted in a timely manner, (2) the description of the event was accurate, (3) a root cause analysis was performed, (4) safety implications were considered,
and (5) corrective actions implemented or planned were sufficient to preclude recurrence of a similar event.
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LER 93-02, " Missed Technical Specification Surveillance, Source Check of Steam Jet Air Ejector Process Monitor Due to Inadequate Training" (Section 4.2.2).
LER 93-04, " Jet Pump Surveillance Not Performed During Single loop Operation as Required by Technical Specifications Due to an Ambiguous Technical Specification Requirement." The NRC review of the issue is discussed in NRC Inspection Report 93-03.
j Further review of VY corrective actions will be performed during followup inspections of
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Unresolved Item (URI) 93-03-01.
9.0 MANAGEMENT MEETINGS (30702)
9.1 Preliminary Inspection Mndings I
Meetings were periodically held with plant management during this inspection to discuss inspection findings. A summary of preliminary findings was also discussed at the conclusion of the inspection on April 19. No proprietary information was identified as being included in the report.
9.2 Management Meeting - Security On April 8, VY representatives attended a meeting held at the NRC office. In accordance with a recommendation made by the NRC at the conclusion of the previous Systematic Assessment of Licensee Performance period, the purpose of the meeting was to discuss an independent assessment of the physical security program being implemented at Vermont Yankee. An independent assessment of the station's intrusion detection system and other sensitive program issues were also discussed. Details of the discussions are deemed to be safeguards information and are, therefore, exempt from public disclosure in accordance with 10 CFR 73.21. A listing of all attendees is included in Attachment A to this report.
The meeting provided the NRC with valuable insight into VY management's approaches to improving the security program for the station. However, during subsequent inspections, the NRC will review in more detail the findings of the independent assessments and VY's corrective measures to resolve the findings.
9.3 Other Meetings On April 5, the VY Vice President, Engineering and other senior members of the engineering organization attended a meeting at NRC Region I with members of the regional office and the NRC Office of Nuclear Reactor Regulation. The meeting was initiated by VY to discuss recent initiatives in the area of engineering.
On April 8, the VY President and other senior members of his staff attended a meeting with NRC management. The meeting was initiated by VY to discuss management change _.=n
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l ATTACHMENT A
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Licensee:
G. Morgan, Security Manager R. Wanczyk, Plant Manager j
U.S. Nuclear Regulatory Commission. Region I
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R. Cooper, Director, Division of Radiation Safety and Safeguards (DRSS)
J. Joyner, Chief, Facilities Radiological Safety and Safeguards Branch, DRSS l
R. Keimig, Chief, Safeguards Section, DRSS R. Albert, Physical Security Inspector, Safeguards Section, DRSS D. Haverkamp, Chief, Technical Support Staff, Division of Reactor Projects, (DRP)
J. Linville, Chief, Projects Branch No. 3, DRP
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