IR 05000293/1993003
| ML20034F359 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/22/1993 |
| From: | Eugene Kelly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20034F353 | List: |
| References | |
| 50-293-93-03, 50-293-93-3, NUDOCS 9303030058 | |
| Download: ML20034F359 (12) | |
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U. S. NUCLEAR REGULATORY COMMISSION
REGION I
Docket No.:
50-293 Report No.:
93-03 Licensee:
Boston Edison Company 800 Boylston Street Boston, Massachusetts 02199 Facility:
Pilgrim Nuclear Power Station Location:
- Plymouth, Massachusetts Dates:
January 1 - February 10,1993 Inspectors:
J. Macdonald, Senior Resident Inspector D Ke', Resident Inspector W [# r 2 / u b3 Approver' by:
E. Kelly, Chief bate Reactor Projects Section 3A Scope:
Resident safety inspections in the areas of plant operations, radiological controls, maintenance and surveillance, security, safety assessment and quality verification, and engineering and technical support. Initiatives selected for inspection included battery surveillance procedures and instrument air system reliability.
Inspections were performed on backshifts during January 4-6,- 12-15,' 19-22,25, and 27-29, and February 2, 3, and 10. " Deep" backshift inspections were performed on January 3 (10:55 a.m. to 7:25 p.m.), January 18 (7:25 a.m to 2:15 ~
p.m.) and January 26 (4:00 to 5:00 a.m.).
Findings:
Performance during this six week period is summarized in the Executive Summary. Unresolved item 91-04-01 regarding HPCI and RCIC room cooler redundancy was updated and left open.
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L, EXECUTIVE SUMM ARY
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Pilgrim Inspection Report 50-293/93-03 Plant Operations: Good attention to detail during operator rounds identified backleakage past the "B" salt service water pump discharge' check valve. Backshift inspections found station personnel to be attentive to assigned responsibilities.
Radiological Controls:
Daily management review of specific work activities effectively
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optimized both job performance and personnel exposure planning.
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Maintenance and Surveillance: The preventive maintenance program associated with the instrument air system has been recently expanded to improve overall reliability. However, root cause evaluation of recent air compressor failures has been indaterminate, and continued trending i
of air compressor performance is being considered. A Betterment Review Team was established to formalize coordination efforts at reducing the severe weather effects of salt buildup on 345 KV switchyard conductors.
Security: Alarm station turnover activities were observed to be effective. Compensatory measures were properly stationed and attentive to assigned responsibilities.
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Safety Assessment and Quality Verification: Licensee Event Reports provided good detail and properly addressed reporting criteria. Quality Assurance Department auditors independently and--
l cffectively assessed operator tours. - Plant organizations were responsive to QAD findings, clear performance expectations were established, and line management were effective in reinforcing those standards.
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SUMMARY OF FACILITY ACTIVITIES.
At the start of the report period Pilgrim Nuclear Power Station was operating at approximately 100% of rated power. On January 15 and February 2, reactor power was temporarily reduced to approximately 50% to perform backwashes of the main condenser.
On January 26, the high pressure coolant injection (HPCI) system was declared inoperable due to a blown fuse in the flow controller circuit that was identified during a routine surveillance.
The licensee properly notified the NRC in accordance with 10 CFR 50.72. The fuse was replaced and the HPCI system was promptly retested satisfactorily and returned to service later on January 26. Pilgrim Station was operating at 100 percent at the close of this reporting period.
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2.0 PLANT OPERATIONS (71707, 40500, 90712)
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2.1 Plant Operations Review The inspector observed the safe conduct of plant operations (during regular and backshift hours)
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Control Room Fence Line Reactor Building (Protected Area)
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Diesel Generator Building Turbine Building j
Switchgear Rooms Screen House j
Security Facilities l
Control room instruments were independently observed by NRC inspectors and found to be in correlation amongst channels, properly functioning and in.conformance with Technical j
Specifications. Alarms received in the control room were reviewed and discussed with'the operators; operators were found cognizant of control board and plant conditions. Control room
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and shift manning were in accordance with Technical Specification requirements. Posting and -
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control of radiation contamination, and high radiation areas were appropriate. Workers complied with radiation work permits and appropriately used required personnel monitoring devices.
Plant housekeeping, including the control of flammable and other hazardous materials,. was observed. During plant tours, logs and records were reviewed to ensure compliance with station
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procedures, to determine if entries we-re correctly made, and to verify correct communication-
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of equipment status. These records included various operating logs, turnover sheets, tagout, and lifted lead and jumper logs. An operator identified backleakage past the "B" salt service water.
- pump discharge check valve during a routine plant tour and initiated appropriate corrective actions, j
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2.2 Backshill Observations On January 26,1992, the inspector conducted an extensive backshift tour of the station. Control room operators were observed to be alert, logs were verified to be current, and activities were -
found to be conducted with good communications and formality. The inspector independently toured the emergency diesel generator building, the intake structure, the salt service water pipe replacement construction site, and various security facilities. Licensee personnel were observed to be alert and attentive to their responsibilities. The Nuclear Watch Engineer accompanied the inspector during a review of switchyard activities supporting the isolation of the ACB-103 breaker for maintenance. The Nuclear Operations Supervisor (a licensed senior reactor operator)
and Nuclear Plant Reactor Operators (licensed reactor operators and non-licensed personnel)
located at the switchyard relay house were observed to be establishing and verifying isolation boundaries for the breaker maintenance. Appropriate procedures and drawings were being used.
The inspector discussed backshift watch expectations with the NWE. The NWE demonstrated a sound awareness of the procedural requirements for the conduct of operations, and provided an excellent response to NWE supervisory responsibilities in the event that an employee encountered during backshift hours were to appear inattentive.
3.0 RADIOLOGICAL CONTROLS (71707)
The inspector reviewed radiological controls in place as well as the radiological conditions of selected areas of the plant.
BECo management tours of the radiological controlled area continued to be thorough and directed towards minimizing total personnel radiological exposure.
Daily management reviews of personnel radiation exposure applied scrutiny towards both job performance and exposure planning. Survey postings, radiological conditions and controls were appropriate, with no discrepancies noted.
4.0 MAINTENANCE AND SURVEILLANCE (37828,61726,62703,93702)
4.1 Instrument Air System Reliability Background The instrument air system is designed to supply clean, dry air to various station instrumentation and controls including the outboard main steam isolation valves, scram valves, and feedwater regulating valves at pressures of 70 to 100 pounds per square inch gauge.. On October 25,1992, with the reactor mode select switch in the shut down position, a rupture of the reactor building (RA) outer trucklock door inflatable seal placed a sudden increased demand on the instrument -
air system. This caused the instrument air header pressure to lower resulting in the automatic isolation of the service and non-essential instrurnent air headers as designed. At the time of this event, one of the five installed instrument air compressors was unavailable due to the midcycle outage electrical bus alignment. Two of the remaining air compressors (K104B and K104C)
failed to start both automatically and manually. The K104C motor overheated and was damaged during the manual start attempts. The two remaining instrument air compressors were unable
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to maintain full pressure to the essential instrument air header. Operators placed the diesel powered portable air compressor in service in accordance with procedures 5.3.8, " Imss of Instrument Air" and 2.2.36, " Operation of the Temporary Air Compressor" to stabilize instrument air header pressure until the source of the leak was identified and isolated. In response to this casualty, use of existing procedures and availability of the portable air compressor were sufficient to ensure functionality of the instrument air system. Based upon the system response to this event, the inspector conducted a review of instrument air system
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maintenance practices and overall system reliability.
Corrective Actions
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f Problem report (PR) 92-9205 was issued to determine the cause of the RA truck lock door seal rupture and to initiate appropriate actions to prevent recurrence. The licensee determined that an instrument air pressure regulator to the door seal failed open and that the associated downstream pressure relief valve had failed to lift. The inflatable seal was then overpressurized i
and it subsequently ruptured. Immediate corrective actions included isolation of the instrument air system to the seal, repair of the seal, replacement of the pressure regulators for both RA trucklock door seals, and the refurbishment, bench test,'and reinstallation of both relief valves.
Long term recommendations included modification of procedures to include daily verification of regulator pressure and relief valve operability when the RA trucklock door seals are inflated.
In addition, an evaluation was initiated to determine whether the current relief valve design was correct for this application, or whether a newer design should be implemented. These corrective actions were appropriate to preclude recurrence of a similar failure of the RA trucklock door seal.
The licensee initiated PR 92-0492 to determine why air compressors Kl_04B and K104C had failed to start during the event and to implement corrective actions. Troubleshooting of K104B was unable to repeat the failure and no root cause was identified. Following successful demand start testing, K104B was returned to service. The motor insulation of K104C was found overheated and damaged. No signs ofinsufficient ventilation or foreign materials were observed and no definite cause of the failure was determined. The licensee therefore concluded that the
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most probable cause of the K104C motor overload was motor insulation resistance breakdown associated with motor age.
.j A new motor was installed and K104C was returned to service on January 21,1992 following a successful post work capacity test. The pre-evolution briefing by the maintenance supervisor was good and communications were properly established. The inspector noted that one of the prerequisites for the test was not satisfied and questioned whether the procedure could be performed as written. Following discussion, the Nuclear Watch Engineer (NWE) exempted the i
prerequisite in question and instructed thejob supervisor to continue the procedure. In addition, the NWE instructed the job supervisor to initiate a permanent change to the procedure to delete
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the subject prerequisite. The inspectc* determined that this resolution was acceptable. Workers
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promptly identified a discrepant lube oil level as a small air cavity became filled upon start of the compressor. The oil was topped off and the capacity test was recommenced. Performance data collection and communications were excellent throughout the procedure.
N'RC Conclusions The inspector reviewed the maintenance history of the five station air compressors for the past two years. With one isolated exception, the compressors had been maintained and successfully tested within the specified periodicity. No history of repeated failures was evident. The inspector noted that the licensee had recently expanded the existing preventive maintenance (PM)
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program to incorporate the instrument air compressors in the rotating equipment vibration monitoring program. The use of vibration data was successful in identifying a loose corner support footing following replacement of the K104C motor. In addition, the reliability centered maintenance (RCM) program reviewed the instrument air system in July 1992 and recommended several additions to the PM program. These were positive initiatives to improve the overall reliability of the instrument air system. However, the inspector noted that the licensee had not definitively identified the failure :echanism for the K104B and K104C air compressors.
Without the cause identified and corrected, the air compressors remain susceptible to the same failure mechanism observed on October 25.
The inspector questioned whether the licensee had evaluated developing a PM process to trend motor performance or insulation resistance in an effort to improve component reliability.
System engineers stated that existing test equipment would not provide useful information for small motors such as the instrument air compressor motors. Further discussion indicated that the licensee was procuring a motor circuit analyzer which could potentially provide more useful motor performance trending information. The inspector discussed this with the Mechanical Systems Division Manager, who stated the intention to further consider development of a process to trend motor performance.
t inspector review of the October 25,1992 event as well as performance data for the last two years concluded the instrument air system has operated and been maintained adequately.
Initiatives to expand the PM program and develop predictive maintenance trending were discussed, but have not yet been implemented.
4.2 Battery Surveillance Procedure Review i
The inspector reviewed battery surveillance procedures 3.M.3-25.10 " Weekly Battery Pilot Cell and Charger Inspection," 8.C.14 " Weekly Pilot Cell, Overall Battery Check, and Battery Charger Test", and associated vendor manuals to verify that battery and battery charger parameters were properly monitored at required intervals. Minor procedure and performance discrepancies including incorrect specific gravity corrections, and incomplete management reviews were noted. Notwithstanding t!.e noted discrepancies, the inspector concluded that the procedures were adequate for the intended work activities.
The procedure discrepancies identified did not impact the operability of the batteries or battery chargers which were
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surveilled. The noted discrepancies were discussed with licensee management who committed to proper resolution. Additionally, the licensee committed to verifying that the density meter instrument used for electrolyte specific gravity measurements was being properly utilized.
4.3 Switchynrd Salt Spray Buildup Prevention Saltwater spray buildup has contributed to arcing and electrical transients in the 345 KV switchyard, resulting in plant trips during periods of severe weather. The licensee recently established a 345 KV switchyard Betterment Review Team to identify and evaluate methods of reducing susceptibility to arcing and to improve overall switchyard performance.
Initial preventive measures included periodic isolation of sections of the 345 KV switchyard during periods of good weather for demineralized water washdown of insulators. Maintenance and Operations staff were coordinated to perform the recommended insulator washdowns on January 23-24. Pollution / salt buildup samples were taken to evaluate the extent and effects of permanent film buildup. Long term actions identified for consideration included: evaluation of an improved insulator coating; replacement of insulators with a design less susceptible to salt / pollution buildup; and, development of a predictive testing procedure. The inspector discussed the results of the initial issue meeting with the team leader and determined that the licensee had developed
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a sound plan.
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4.4 Routine Surveillances The inspector observed portions of surveillances to verify proper calibration of test instrumentation, use of approved procedures, performance of work by qualified personnel, conformance to limiting conditions for operation (LCO), and correct system restoration following.
testing. The following surveillances (with comments as noted) were observed:
Procedure 8.9.1, " Emergency Diesel Generator " was performed with satisfactory results
on January 3,1993.
Operators demonstrated a good working knowledge of the procedure and properly maintained communications between the two controlling stations.
Procedure 8.M.1-32.4, " Analog Trip System - Trip Unit Calibration - Cabinet <-B2
(High Risk Test)" was performed with satisfactory results on January 29,1993. This
surveillance was performed to verify proper functional performance and setpoint calibration of several instruments which provide automatic trip signals to the reactor-protective system. Technicians properly requested and received supervisor resolution.
when unanticipated questions, such as indeterminate component labeling, arose.
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Independent quality control review of work practices was. noted throughout the procedure. Communications were properly established between control room operators and the technicians at the instrument cabinet within the plant.'
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demonstrated good procedural compliance and teamwork throughout the surveillance.
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5.0 SECURITY (71707)
Selected aspects of plant physical security were reviewed during regular and backshift hours to verify that controls were in accordance with the security plan and approved procedures. This review concluded that performance was acceptable and included the following security measures:
security force staffing; vital and protected areas barrier integrity; maintenance ofisolation zones; behavioral observation; and, implementation of access control including access authorization and badge issue, searches of personnel, packages and vehicles and escorting of visitors. The inspector observed turnover of the Central Alarm Station personnel during " deep" backshift hours. The security personnel demonstrated complete awareness of security status and conducted a comprehensive turnover. Compensatory personnel stationed to support the salt service water
system pipe replacement were observed to be alert.
6.0 SAFETY ASSESSMENT AND QUALITY VERIFICATION (92701)
6.1 Licensee Event Report (LER) Review
LER 92-13 LER 92-13, " Automatic Closing of Group 1 Containment Isolation Valves due to False Reactor
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Vessel High Water Level Signal," describes the October 24,1992 automatic actuation of the main steam system / group 1 portion of the primary containment isolation control system that occurred due to a false high reactor vessel water icvel signal. This event is documented in NRC inspection Report 50-293/92-23. The LER provided a detailed review of the event and causal contributors.
- LER 92-14 LER 92-14, " Automatic Closing of the Inboard and Outboard Primary Containment System j
Group 6 Isolation Valves During Startup," describes the November 24,1992 automatic actuation
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of the inboard and outboard reactor water cleanup (RWCU) system portions of the primary containment isolation control system (PCIS). The PCIS isolation was in response to a sensed high RWCU flow condition which occurred while restoring valve MO-1201-2 to its normal inservice position. The root cause of the event was determined to be a procedural weakness, in that procedure 2.2.83, " Reactor Cleanup System" did not identify the required position of a l
letdown piping valve when returning the system to service with the reactor vessel pressurized.
The event posed no threat to public health or safety, and the LER properly addressed reporting criteria.
- LER 92-15 LER 92-15, " Reactor Core Isolation Cooling System Became Inoperable due to Turbine Trip Throttle Valve Closing," describes the Novea1ber 25,1992 inadvertent trip of the reactor core isolation cooling (RCIC) system turbine trip-throttle valve (SV-1301-1). While reinstalling
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insulation in the vicinity of RCIC turbine steam supply valve, a worker inadvertently contacted the RCIC trip-throttle valve linkage, causing SV-1301-1 to shut. The RCIC turbine was idle at the time of the event. Operators properly reported the event and promptly reset the trip-throttle valve. Corrective action included counselling of the insulation workers and their job supervisor regarding the status of equipment and components in their work area and communications with the control room.
- LER 92-16
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LER 92-16, " Automatic Scram Resulting from Imad Rejection at 48 Percent Reactor Power,"
describes the December 13, 1992 automatic scram which resulted from excessive 345 KV switchyard flashover during a severe coastal storm. The load rejection included a trip of the main turbine, closure of the turbine control valves and opening of the bypass valves, and automatic transfer of the auxiliary power distribution system. This event is further documented in NRC Inspection Report 50-293/92-28. Corrective actions included washdown of 345 KV switchyard components to remove the salt spray buildup, establishment of an issue team to develop a 345 KV switchyard betterment program (see Section 4.3), and consideration to install a replacement switchyard events recorder. The LER provided a thruugh description of the event and detailed root cause analysis.
6.2 Verification of Plant Records The inspector documented NRC and licensee actions to determine the effectiveness and accuracy of plant log taking activities in Inspection Reports 50-293/92-08 (section 7.3) and 50-293/92-23 (section 7.2). A licensee Quality Assurance Department (QAD) surveillance, 92-1.1-12, of operator tours for a two week period in September 1992, identified a single entry into a switchgear room that had been logged as accomplished but could not be verified by security computer records. This inconsistency was identified by issuance of QAD deficiency report (DR)
No. 2004. The QAD surveillance observed additional weaknesses in the Operations Section self-
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monitoring program of operator tours. These weaknesses were identified by issuance of QAD
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DR No. 2005. Corrective actions to DR No. 2005 were promptly implemented by Operations Section management, and the deficiency was closed.
Beginning on February 1,1993, QAD initiated a 12 day follow-up surveillance, 93-9.4-07, in the area of operator rounds. The surveillance reviewed corrective actions to DR Nos. 2004 and
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2005, compared selected log entries and security computer records for a two week period in December 1992, nd performed an independent turbine building tour to compare Qf.A auditor acquired readings with the concurrent operator tour readings. The Surveillance determined that the corrective actions to DR No. 2004 were effective. Operations Section management met with
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each operating crew to clearly state expectations for conduct and documentation of operator tours. The QAD auditors interviewed various operators and concluded the expectations were l
uniformly stated and understood. Additionally, the previous corrective actions to DR No. 2005 were verified to be effective through determination that periodic Operation Section self-monitoring procedures were being implemented in accordance with established periodicitie _ __
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Additionally, QAD performed a comparison of operator tours with security computer records -
for the period December 27,1992 through January 9,1993. Plant areas reviewed included the switchgear rooms, vital M-G set room, standby gas treatment system room, auxiliary bay, emergency diesel generator building, salt service water pump rooms, augmented offgas system
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building, selected security facilities, the main stack, and reactor buildings. No discrepancies i
l were identined. Similarly, a comparison of a QAD turbine building tour to actual operator tour data for February 7,1993 identined no discrepancies.
The inspector conducted several discussions with Operations Section management regarding the j
previous QAD-identined de6ciencies. The inspector concluded that: (1) management was
'l responsive to the QAD findings; (2) clear standards of performance expectations were established with respect to conduct of operations; and, (3) management had effectivdy reinforced
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i these standards through one-on-one meetings with each operations shift crew. Independent QAD verification of operator rounds remains effective.
7.0 ENGINEERING AND TECIINICAL SUPPORT (71707)
7.1 Open item Follow-up 7.1.1 (Update) Unresolved Item 50-293/91-04-01, HPCI, RCIC Area Coolers On February 10, 1993, the inspector met with BECo licensing and engineering staff at the Nuclear Engineering Department offices in Braintree to discuss the status of an inspector concern regarding area coolers for the high pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) systems. SpeciGcally, as documented in NRC Inspection Report 50-293/91-04, the March 25,1991 loss of A-6 bus event caused power to both HPCI area coolers to be lost and required HPCI to be declared inoperable.
FSAR Section 10.18, Emergency Area Cooling System (EACS), indicates that the system is designed with sufficient redundancy so that no single active component failure can prevent the j
system from achieving its safety objective. The safety objective of the EACS, as described in
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the FSAR, is to maintain the local environment of the electrical components of the core standby cooling systems (CSCS) at temperatures within their maximum allowable operating limits.' _ The inspector questioned if the FSAR description of EACS redundancy was accurate in that, on March 25,1992, the single active failure of the A-6 bus caused electrical power to both HPCI area coolers to be unavailable. Although not a factor in the March 1992 event, the same scenario would be applicable to the RCIC system in the event of a loss of power to the A-5 bus.
It appears that the operability of either the HPCI or RCIC systems should be independent of a design basis single active AC power failure.
The licensee Unished their research of construction and licensing basis documentation related to HPCI and RCIC area cooling. A draft evaluation that details this effort has been developed.
I Cognizant licensing engineers indicated that BECo's preliminary position is that the current EACS design is appropriate, and conforms with the station operating license. The draft
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evaluation was reviewed and recommended for approval by the NED Design Review Board.
The evaluation remains to be reviewed by the Onsite Review Committee for recommendation of station management approval. This item remains open pending final licensee evaluation and independent NRC assessment of adequacy.
8.0 NRC MANAGEMENT MEETINGS AND OTIIER ACTIVITIES (30702)
8.1 Routine Meetings At periodic intervals during this inspection, meetings were held with senior plant management to discuss licensee activities and areas of concern to the inspectors. At the conclusion of the -
reporting period, the resident inspector staff conducted an exit meeting on February 11 summarizing the preliminary findings. No proprietary information was identifxd as being included in the report.
b.2 Management Meetings On February 3, at the request oflocal elected officials, the NRC conducted a public meeting to present an information update and respond to questions concerning the performance and
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reliability of reactor vessel water level instrumentation at Pilgrim Station.
On February 3,.Mr. C. William Hehl, NRC Region I Director of Reactor Projects and Mr.-
Gene Kelly, Chief, Reactor Projects Section 3A toured Pilgrim Station with' the resident inspectors and met with licensee management to discuss current licensee performance.
8.3 Other NRC Act'"' tics On January Il-15, two NRC Region I operator licensing specialists conducted an inspection of the licensee emergency operating procedure program, inspection results will be documented in NRC Inspection Report 50-293/93-01.
On January 11-15, an NRC Region I materials specialist conducted an inspection of the licensee piping support and restraint testing program. Inspection results will be documented in NRC-Inspection Report 50-293/93-02.
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