IR 05000309/1993002
| ML20034F566 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/25/1993 |
| From: | Lazarus W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20034F562 | List: |
| References | |
| 50-309-93-02, 50-309-93-2, NUDOCS 9303040006 | |
| Download: ML20034F566 (10) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report 93-02 License DPR-36 Inspection At:
Maine Yankee Atomic Power Plant
Wiscasset, Maine (Maine Yankee Atomic Power Company)
'I Conducted:
January 1 through February 5,1993 Inspectors:
Charles S. Marschall, Senior Resident Inspector
William T. Olsen, Resident Inspector Approved:
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W.1(azaius3hief, Reactor Project Section 3B Date
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SCOPE l
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Resident inspection of operations, radiation protection, maintenance / surveillance, security, engineering / technical support, and safety assessment / quality verification.
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OVERVIEW -
.i Ooerations Operators responded conservatively to a failure of the main generator leads
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cooling fan. They proficiently conducted an accelerated plant shut down, preventing a
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possible plant trip and degradation of the main generator. - Maine Yankee responded to an-
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emergency diesel generator output circuit breaker failure with thorough assessment and j
j inspection of the motorized emergency diesel generator. Maine Yankee management
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demonstrated good safety perspective by taking the plant offline to investigate the cause of increasing vibration in a Reactor Coolant Pump. Continued operation, although not i
jl prohibited by pump performance, would have involved greater chance of pump or motor failure and potential challenge to safety systems.
d Radiological Controls. The radiological controls department improved' performance'of portal
.i monitors by adding features to insure that workers' arms are monitored and to prevent passing through the frisker without being monitored.
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Maintenance and Surveillance Maine Yankee responded to the failure of an emergency
'll diesel generator output breaker with thorough assessment and inspection of the emergency'
' diesel generator. A control room operator carefully performed a Control Element Assembly-
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(CEA) surveillance, and appropriately communicated a CEA dual indication problem l to his -
j supervisor. An auxiliary operator (AO) performing a monthly fire pump test displayed -
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familiarity with the procedure and the equipment and performed the required testing in a safe -
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j and controlled manner. During preventive. maintenance _of the Component Cooling Water q
pumps, plant staff carefully adhered to Work Orders and procedures, and adequately.
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controlled P-9B and P-10B removal from service and restoration. Inspectors closed _an open
- j item associated with surveillance procedure acceptance criteria.
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9303040006 930225 i
PDR ADOCK 05000309-j
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(OVERVIEW CONTIN'UED)
Security Security identified a bottle containing alcohol during a routine search. Maine Yankee management took appropriate corrective action. Security measures taken in response to a previous search problem associated with an alcoholic beverage were effective.
Engineering and Technical Sunnort Engineering staff reviewed the impact of plant operation with decreased steam pressure on assumptions in the accident analysis. They appropriately concluded that continued plant operation did not constitute an unreviewed safety question. In addition, the engineering staff proposed a testing program to monitor the effects ofincreased steam flow and moisture content on plant equipment.
Safety Assessment and Ouality Verification Inspectors closed an open item related to reports required by 10 CFR 50.73.
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TABLE OF CONTENTS OVERVIEW.............
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TABLE OF CONTENTS.......................................iii 1.
OPERATIONS
........................................~1 1.1 Failure of Main Generator Leads Cooling Fan (71707)
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1.2 Plant Shutdown Due to Reactor Coolant Pump High Vibration (71707)
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RADIOLOGICAL CONTROLS............................... ~2 2.1
. Portal Monitor Modification (71707)
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MAINTENANCE and SURVEILLANCE......................... 2 3.1 Emergency Diesel Generator Surveillance (61726)............... 2 3.2 Control Element Assembly Surveillance (61726)
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3.3 Monthly Fire Pump Surveillance Testing (61726)................ 4 3.4 Repair of Emergency Diesel Generator Circuit Breaker (62703)....... 4 3.5 Preventive Maintenance of Component Cooling Water Pumps (62703)...
3.6 (Closed) Violation 91-08-02, Surveillance Procedure 3.1.5 Acceptance Criteria (92702)........
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SECURITY
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4.1 Access Control (71707)..
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ENGINEERING and TECHNICAL SUPPORT
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5.1 Degraded Steam Generator Heat Transfer (71707)
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SAFETY ASSESSMENT and QUALITY VERIFICATION
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6.1 (Closed) Violation 92-80-05, Failure to Make Reports Required by 10 l
C F R 5 0. 73 (9 2 702 )................................... 6 7.
A DM I NISTR ATIVE......................................
7-d 7.1 Persons Contacted...........
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7.2 Summary of Facility Activities........................... 7
Interface with the_ State of Maine.......................... 7
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7.4 NRC Inspection Activities at Maine Yankee.................... 7
7.5 Exi t M eeti n g...................................... 7
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DETAILS 1.
OPERATIONS On a daily basis, inspectors verified adequate staffing, appropriate access control, adherence to procedures and Limiting Couditions for Operation, operability of protective systems, status of control room annunciators, status of radiation monitors, emergency power source operability, and operability of the Safety Parameter Display System (SPDS). Each week, the inspectors verified operability of selected Engineered Safety Features (ESF) trains and assessed the condition of the plant equipment, radiological controls, security and safety. The inspectors performed biweekly review of a safety-related tagout, chemistry sample results, shift turnovers, portions of the containment isolation valve lineup, the posting of notices to workers and operability of selected ESF trains. The inspectors evaluated plant housekeeping and cleanliness.
1.1 Failure of Main Generator Leads Cooling Fan (71707)
On January 3, an Auxiliary Operator reported loud noise and vibration in the main generatur lead cooling fan. Control room operators reduced power to 87%, as required by procedure, to compensate for reduced heat removal from the generator leads. After assessing the condition of the fan, plant staff decided to continue the plant shut down in anticipation of the fan failure. Control room operators took the plant off line approximately two hours after initiating the shutdown. On January 4, maintenance staff completed repairs to the fan, and the operators began a plant startup. The control room staff successfully phased the generator to the grid late on January 4.
The operators responded appropriately to the failure of the leads cooling fan. They pronciently conducted an accelerated plant shut down, preventing a possible plant trip and degradation of the main generator.
1.2 Plant Shutdown Due to Reactor Coolant Pump Iligh Vibration (71707)
On January 31, when vibration in the no. 3 Reactor Coolant Pump (RCP) bearings reached the alarm setpoint of 18 mils, Maine Yankee plant management directed operators to conduct a normal plant shutdown. The pump manufacturer, Byron Jackson, discouraged pump operation for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with vibration greater than 20 mils. Operators took the generator off the grid at 4:00 am on Monday, February 1. When Maine Yankee engineering personnel tested the pump they discovered a loose motor coupling shaft key. After operators shut the pump off, plant staff found that a worn keyway caused the k>ose key. The plant engineering department developed a temporary modification to secure the shaft key in position until the next refueling outage, when permanent repairs will be completed.
Operations personnel restarted the RCP and subsequent testing indicated that bearing vibrations had dropped to 14-15 mil I
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Maine Yankee management demonstrated good safety perspective by taking the plant off line to investigate the cause of increasing vibration in the RCP. Continued operation, although not prohibited by pump performance, would have involved greater chance of pump or motor failure and potential challenge to safety systems.
2.
RADIOLOGICAL CONTROLS Inspectors routinely reviewed radiological controls including Organization and Management, external radiation exposure control and contamination control. The inspectors also monitored standard industry radiological work practices, and conformance to radiological control procedures and 10 CFR 20 requirements.
2.1 Portal Monitor Modification (71707)
On January 25 and 27, Maine Yankee personnel, with the assistance of a contractor, modified the portal monitors at the exit from the radiologically controlled area (RCA).
Maine Yankee requires radiation workers to use the portal monitors to survey the whole body for external contamination, prior to exiting the RCA. Prior to installing the modification, the portal monitor could not adequately survey a radiation worker's arms due to the configuration of the equipment operating switches. The modificaticn insured that the portal monitor will adequately survey a worker's arms. In addition, an alarm feature was added to prevent personnel from passing through the portal monitor without completing a whole body frisk. Maine Yankee installed the portal monitor modification in accordance with station policy for level three maintenance, which does not require a station work order for accomplishment. The equipment is considered portable and is routinely serviced by the vendor for normal repairs and modi 0 cations. The inspector observed appropriate station personnel involved in the modification process and the post modification testing prior to placing the equipment back into service. The modification was wc'l controlled and the radiation protection department demonstrated an excellent safety perspective by installing the equipment upgrade.
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MAINTENANCE and SURVEILLANCE The inspectors observed and reviewed maintenance and problem investigation activities to verify compliance with regulations, administrative and maintenance procedures, codes and standards, proper QA/QC involvement, safety tag use, equipment alignment, jumper use, personnel qualifications, radiological controls for worker protection, retest requirements, and reportability per Technical Specifications.
3.1 Emergency Diesel Generator Surveillance (61726)
On January 12, operations staff conducted monthly surveillance testing of emergency diesel generator DG-1B. At the completion of the two hour run required by Technical Specification 4.5.A.1, operators reduced electrical load on the EDG to 200 kw, and attempted to open the
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output breaker, as required by procedure 3.1.4. When the output breaker failed to open in response to manipulation of the switch on the main control board, the operator attempted to open the breaker by manipulating the switch a second time. When the second attempt did not open the output breaker, the control room dispatched an auxiliary operator to the local panel to open the breaker. Control room operators observed the illumination of panalarm SS-4-70, Locked Out Diesel Generator 1B Stan, saw EDG load drop to zero, and observed reactive load increase from zero to 500 vars in. Control room personnel realized that the generator had been motorized, and sent an operator to the switchgear to manually trip the output breaker. The operator successfully tripped the output breaker. Plant staff remeved the 4160 V breaker from its cubicle, and replaced it with a spare breaker. Repair of the faulty breaker is discussed in section 3.4, below. Plant engineering evaluated the effect of motorizing the EDG and concluded that it experienced approximately 31.3% of rated load.
In addition, maintenance staff and a vendor technical representative inspected the air box, top deck, piston carriers and rods, turbo inlet, bearings, crankcase, and generator to engine coupling. They did not fm' d any areas of concern. Operations staff subsequently performed a successful test of EDG-1B, and declared it operable.
Maine Yankee responded to th' "reaker failure with thorough assessment and inspection of
'he motorized emergency diesel generator. At the conclusion of the inspection period, the operations manager had not completed his evaluation of areas for improvement in the procedure for operations surveillance of the emergency diesel generators.
3.2 Control Element Assembly Surveillance (61726)
On January 11, Maine Yankee operations personnel conducted surveilhu.cc testing of the reactor control element assemblies (CEAs). Operators perform the monthly testing, as required by Technical Specification 4.2 to verify CEA operability.
A licensed reactor operator conducted the test as directed by station procedure 3.1.8, revision 25, Control Element Assembly Excreising. The reactor operator displayed familiarity with the procedure and demonstrated excellent safety perspective when he observed dual indication for rod 39. Tite display simultaneously indicated that the rod was at the upper electrical limit and also in the normal operating range. The reactor operator brought this discrepancy to the attention of the shift operating supervisor and the instrumentation and controls technician, that was present during the testing. The dual indication had been previously noted during CEA testing and a work order was written to adjust or repair the reed switches during the upcoming outage. The inspector observed that Maine Yankee's efforts to improve operator use of procedures is achieving results as indicated by the performance of the personnel that conducted this surveillance tes.
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3.3 Monthly Fire Pump Surveillance Testing (61726)
On January ll, Maine Yankee operations personnel conducted monthly fire pump testing of the diesel and electric motor driven fire pumps. Technical Specification 4.12.B.2 requires monthly testing to verify operability of the fire pumps. The auxiliary operator (AO)
performed the required testing using station procedure 3.1.9, revision 22, Fire Pump Testing. The AO displayed familiarity with the procedure and the equipment and performed the required testing in a safe and controlled manner.
During the test the inspector noted that the operator throttled fire pump flow through gate valve FS-19 to provide recirculation from the discharge of the fire pump back to the fire pond. The inspector noted a considerable amount of flow induced noise coming from the area of the valve. The inspector noted that gate valves are not normally used for throttling flow due to poor throttling characteristics and possible accelerated valve disc and seat erosion. Plant staff informed the inspector that FS-19 had never been inspected for wear.
Degradation of FS-19 could divert water, needed to combat a fire, from the fire main into the fire pond. Maine Yankee is evaluating the suitability of FS-19 in its use in the fire pump surveillance.
3.4 Repair of Emergency Diesel Generator Circuit Breaker (62703)
As described in section 3.1, above, the EDG-1B output breaker failed to open in response to remote actuation during routine surveillance testing. The operations department initiated a work order to troubleshoot and repair the circuit breaker. During maintenance, electricians identified a burned-out trip coil as the cause for failure of the circuit breaker trip. Plant engineering personnel determined that the trip coil had mechanical binding which prevented the trip coil from de-energizing. The trip coil is not designed to remain continuously energized and subsequently failed.
Maine Yankee personnel reviewed plant machinery history records, vendor notices, and industry failure reports and did not identify any previous failures of the circuit breaker trip coil. The plant engineering department is continuing its evaluation of the root cause of the trip coil mechanical binding.
3.5 Preventive Maintenance of Component Cooling Water Pumps (62703)
Maintenance staff changed the oil in Primary Component Cooling Water (PCCW) pump P-9B and Secondary Component Cooling Water (SCCW) pump P-10B on January 22. The mechanics performed the work as directed by Work Orders (WO) 92-6945 and 92-6947, using maintenance procedure 5-84-1, revision 5, Equipment Lubrication. Maintenance personnel closely adhered to the instructions in WO 92-6945, WO 92-6947, and procedure 5-84-1. The inspectors verified that operations staff tagged out P-9B and P-10B prior to the
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A work, and correctly restored the pumps to an operable status on completion of the. work. In -
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addition, the inspectors verified the operability of the redundant pumps P-9A and P-10A :
during the maintenance activity.
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The Maine-Yankee work control process ensured adequate control of safety'related.
maintenance on the CCW pumps, and insured operability of redundant components. In-
addition, plant staff carefully adhered to Work Orders and procedures, and adequately.
t controlled P-9B and P-10B removal from service and restoration.
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i 3.6 (Closed) Violation 91-08-02, Surveillance Procedure 3.1.5 Acceptance Criteria
(92702)
j In April 1991, plant staff failed to include appropriate acceptance criteria in surveillance:
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procedure 3.1.5 for emergency feedwater pump P-25C. Maine Yankee had installed new,;
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more accurate flow instrumentation without making appropriate changes to the procedure.
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As a result, the indicated flow, obtained during the surveillance ~, did not fall.within the
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acceptance criteria contained in the procedure. The inspector reviewed procedure 3-1-5.2, j
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revision 1, and 3-1-5.4, revision 1, the current. surveillance procedures for P-25A and P-
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25C, the motor-driven emergency feedwater pumps. The newly rewritten procedures -
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contained acceptance criteria appropriate to the existing instrumentation. This item is closed.
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4.
SECURITY
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The inspectors verified that security conditions met regulatory requirements, the requirements, of the physical security plan, and complied with approved procedures.. The checks included -
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security staffing, protected and vital area barriers, vehicle searches and personnel:
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identification, access control, badging, and compensatory measures when required. No
discrepancies were identified.
4.1 Access Control (71707)-
'i On January 18, during a routine plant access search, Maine Yankee security personnel
detected a bottle containing an alcoholic beverage. Security prevented the bottle from entering the protected area. Maine Yankee management; determined that the employee had i
retrieved a bag containing the bottle and clothing for another employee and was evidently
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unaware of the alcoholic beverage in the bag of clothing. A Maine Yankee management..
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investigation of the incident found that the other employee planned to wear the clothes and -
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consume the beverage during planned recreation at the conclusion of the work day.._The.-
investigation concluded that the Fitness For Duty rule had not been violated, since the
alcoholic beverage did not enter the protected area. The inspectors concluded that Maine
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Yankee management t ok appropriate corrective action, and that security measures taken in o
response to a previous search problem associated with an alcoholic beverage, had been
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effective.
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ENGINEERING 'and TECIINICAL SUPPORT i
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5.1 Degraded Steam Generator IIcat Transfer (71707)
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a From 1989 to the present, Maine Yankee has observed gradual degradation of steam '
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generator steam pressure. During that period, pressure decayed from 845 psig to 790 psig,.
as a result of fouling of the steam generator tube heat transfer surfaces. Maine Yankee
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engineering staff performed an analysis to demonstrate that plant operation with steam
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pressure as low as 738 psig did not invalidate design basis assumptions. ~ Engineering staff found that steam generator steam pressure affected three design basis accidents: loss of load, i
steam generator tube rupture, and a control element assembly withdrawal accident. The
review demonstrated that the accident analyses were bounding for steam generator pressure l
as low as 738 psig with slightly more restrictive acceptance criteria for testing the Reactor j
Coolant System code safety relief valves. The inspector verified that the safety relief valves i
had been tested to the new acceptance criteria.
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In addition to verifying the validity of accident analysis assumptions, Maine Yankee ll engineers proposed a program to investigate the effects of increased steam and feedwater.
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velocity and moisture content on the secondary side of the plant. The engineering staff l
recognized a potential for increased erosion / corrosion effects on secondary system active and
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passive components. The inspectors concluded that the engineering staff thoroughly analyzed
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addition, proposed measures to monitor the effects of reduced steam pressure on plant ~
-l operation demonstrated foresight in maintaining the plant within the conditions assumed in
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the FSAR.
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SAFETY ASSESSMENT and QUALITY VERIFICATION
.i 6.1 (Closed) Viointion 92-80-05, Failure to Make Reports Required by 10 CFR 50.73 (92702)
y This item documented failure to report a missed surveillance required by Technical.
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Specifications and operation of the plant in a condition prohibited by Technical i
Specifications. In response to the Notice of Violation, Maine. Yankee issued a memorandum
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to plant staff requiring that they report missed surveillances required by Technical i
Specifications and operation of the plant in a condition prohibited by Technical j
Specifications. In addition, on October 9,1992, Maine Yankee issued Licensee Event l
Report (I c.R) 92-008-00 to report the operation of the plant in a condition prohibited by
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Technical Specifications, and LER 92-009-00 to report the missed surveillance required by'
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Technical Specifications. This item is closed.
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ADMINISTRATIVE 7.1 Persons Contacted l
During this report period, interviews and discussions were conducted with various licensee personnel, including plant operators, maintenance technicians and the licensee's management j
staff.
7.2 Summary of Facility Activities The plant operated at full power from the beginning of the inspection period until January 3, when operators took the plant off line in response to failure of the main generator leads I
cooling fan. Operators phased the generator to the grid on January 4. The plant operated at full power until January 31, when operators took the plant offline in response to high vibrations in Reactor Coolant Pump RCP-3. Operators phased the generator to the grid on February 4, and the plant operated at full power through the end of the inspection period, 7.3 Interface with the State of Maine Periodically, the resident inspectors and the onsite representative of the State of Maine discussed findings and activities of their corresponding organizations. No unacceptable plant conditions were identified.
7.4 NRC Inspection Activities at Maine Yankee
In addition to the resident inspection activities, an inspector from the NRC, Region I office conducted a routine inspection of the Maine Yankee radiological controls program. The results of the inspection, conducted from January 1 through 4, were documented in NRC l
Inspection Report 50-309/93-01.
7.5 Exit Meeting Meetings were periodically held with senior facility management to discuss the inspection l
scope and findings. A summary of findings for the report period was also discussed at the conclusion of the inspection.
During the inspection period the inspectors conducted backshift inspection on January 15,25, 26,27,29, and February 2, 3. Deep backshift inspection was conducted on January 18.
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