IR 05000309/1993018
| ML20149D311 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 09/14/1993 |
| From: | Lazarus W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20149D301 | List: |
| References | |
| 50-309-93-18, NUDOCS 9309210005 | |
| Download: ML20149D311 (20) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report 93-18 License DPR-36 Inspection At: Maine Yankee Atomic Power Plant Wiscasset, Maine (Maine Yankee Atomic Power Company)
Conducted: July 28 through August 29,1993 Inspectors: Charles S. Marschall, Senior Resident Inspector William T. Olsen, Resident Inspector Peter-lCSena, Resident Inspector, Beaver Valley I & II Approved by: M /'/ W. J. Lazarus, Chief, Reactor P'roject Section 3B date SCOPE I
Resident inspection of operations, maintenance / surveillance, engineering / technical support, and plant suppor OVERVIEW Operations Maine Yankee continued to demonstrate safe, conservative plant operation by commencing a plant shutdown when the no. 2 RCP seal exhibited excessive leakage and started the refueling outage one day early. Plant operators performed a total core off-load in accordance with plant procedures in an excellent manner. Maine Yankee operated throughout the entire cycle without experiencing any automatic or unplanned manual reactor trips or Engineered Safety Feature (ESF) actuations. The Fire Protection System Coordinator improperly compensated for an inoperable fire hose station when he mistakenly rerouted hoses to another inoperable hose station. This resulted in a non-cited violatio Maintenance and Surveillance Maintenance and engineering personnel demonstrated excellent control of in-place Testing of Main Steam Safety Valves. Station operators ,
demonstrated appropriate adherence to procedures during performance of the Turbine Driven Auxiliary Feedwater Pump test. Maintenance of the emergency diesel generators was found 1 to be satisfactory with room for improvement in oversight of vendor activities. Maine Yankee promptly corrected a degraded relay discovered during surveillance testin Engineering and Technical Suonort Plant operations and engineering personnel conducted extensive root cause analysis and corrective action when a circuit breaker overcurrent trip device tripped improperly when a ground developed on the electrical bus. The item was still under investigation at the close of the inspection perio PDR ADDCK 05000309 G PDR
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(OVERVIEW CONTINUED)
Plant Support - Maine Yankee has demonstrated improved radiological controls of contractor -
work during the outage with the inspection of the reactor thermal shield as an example. The ,
inspectors observed many plant managers in the plant on routine tours to identify and correct any outage work related problems. The inspectors noted very good ALARA work controls in use during the outage. Security controls have been excellent as evidenced by access control >
of contractors and plant personnel through the main gatehous ;
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TABLE OF CONTENTS O V E R V I EW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
TABLE OF CONTENTS .......................................iii l i OPERATIONS ........................................ I j Incorrect Compensatory Action for Inoperable Hose Station during ,
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Maintenance ...................................... 1 l M AINTENANCE and SURVEILLANCE . . . . . . . . . . . . . . . . . . . . . . . . . 2 i Main Steam Code Safety Valve Testing . . . . . . . . . . . . . . . . . . . . . . 2 ) Turbine Driven Auxiliary Feedwater Pump Testing . . . . . . . . . . . . . . 2 : Emergency Diesel Engine Maintenance . . . . . . . . . . . . . . . . . . . . . . 3 Emergency Diesel Generator Reliability and Condition Monitoring . . . . . 4 l Emergency Diesel Generator Preventive Maintenance ............. 5 - Degradation of Emergency Diesel Generator Output Voltage Relay . . . . . 6 ENGINEERING and TECHNICAL SUPPORT ..................... 7 Defective Overcurrent Trip Protection Device . . . . . . . . . . . . . . . . . . 7 (Closed) Violation 50-309/92-021-001, Review of Design Basis Eval uati on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 (Closed) Unresolved item 50-309/93-03-02, Diverse Scram System . . . . . 9 3.4- (Closed) Unresolved Item 50-309/91-24-02, Instrument Calibration . . . . 10 P LA NT S U PPO RT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Radiological Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 S ecu ri ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Employee Concerns Program . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 q A D M I NI STR ATI V E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 - Persons Contacted . . . . . . . . . . ....................... 12 , Summary of Facility Activities . . . . . . . . . . . . . . . . . . . . . . . . . . 12 i Interface with the State of Maine . . . . . . . . . . . . . . . ....... . 12 Exit Meeting .................................... 12
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DETAILS
! OPERATIONS On a daily basis, inspectors verified adequate staffmg, appropriate access control, adherence to procedures and Limiting Conditions 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 sampic 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 cleanlines .1 Incorrect Compensatory Action for Inoperable Ilose Station during Maintenance i On June 18, Maine Yankee operations personnel installed danger tags to isolate and drain firemain valve FS-289 for packing repair. The licensee noted that this action would isolate two hose stations that are required to be operable for the protection of component cooling water and service water systems as required by station technical specification Maine Yankee Technical Specification (T.S.) 3.23D requires routing an additional hose of ,
equivalent capacity to the unprotected area from an operable hose station within one hou j Plant support personnel installed additional hoses during the dayshift and the remedial actions of T.S. 3.23D entere ,
I At 11:00 pm the shift operating supervisor (SOS) performed a walkdown of the fire system lineup in order to brief his on-coming relief. He discovered that one of the inoperable hose stations had not been properly compensated for, and that the requirements of the technical specification were not met. He initiated immediate corrective actions and finished by 11:30 pm. After discussion with the Fire Protection Coordinator (FPC), the PSS determined that the hose station was out of service approximately 12.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> Investigation by Maine Yankee management revealed that the FPC had inadvertently rerouted the fire hoses to a hose station that was inside the tagging boundary. This was due to a 1
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mistaken belief that the fire hoses would be from a closer source of fire protection wate He did not realize that further discussion was required with the SOS prior to taking this actio The inspector determined that Maine Yankee's root cause determination was appropriate and the required corrective actions were immediate, comprehensive, and proper to prevent j recurrence. The licensee identified violation was an isolated incident, and the FPC did not willfully violate the tagging order requirements. The safety significance of the event was slight due to two additional hose stations within 75 feet of the safety-related equipment and fire detection monitors and sprinklers in the immediate areas. As a result, this violation will
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not be subject to enforcement action because licensee efforts in identifying and correcting meet the criteria of the Enforcement Policy as specified in 10 CFR Part 2, Appendix C, Section VI . MAINTENANCE and SURVEILLANCE The inspectors observed and reviewed maintenance and problem investigation activities to verify compliance with regulations, administrative and maintenance procedures, work order ,
(WO) requirements, codes and standards, proper QA/QC involvement, safety tag use, l equipment alignment, jumper use, personnel qualifications, radiological controls for worker protection, retest requirements, and reportability per Technical Specifications. The l inspectors observed portions of the following activities: ;
l e WO 93-0616, Replacement of the 'B' Emergency Diesel Generator (EDG) l Turbocharger l
- WO 93-01826 and 93-00171, Annual Diesel Engine Internal Inspections
- WO 93-1436, In-place Testing of Main Steam Safety Valves (Trevitesting)
- Procedure 5-58-1, Revision 19, Inspection, Installation and Testing of the Refueling Cavity Seal Ring
- Procedure 6-02-4, Revision 11, Incore Detector Removal (Wet) (Destructive)
Maine Yankee personnel performed the observed maintenance and surveillance activities in accordance with station directives and procedure i l Main Steam Code Safety Valve Testing j l
l On July 29 and 30, Maine Yankee staff tested the main steam code safety valves using I contractor supplied Trevitesting equipment. Trevitesting utilizes hydraulic pressure to I simulate elevated main steam pressure. The Trevitesting technique permits safety valve !
testing in place on the main steam header, closely simulating actual conditions for valve opening. As a result of the testing, Maine Yankee found that all main steam code safeties i lifted within acceptance criteria limit ;
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The inspectors noted that several Maine Yankee engineering and maintenance personnel oversaw the testing, performed by contractor personnel. The inspectors also noted that a maintenance department work package controlled the activity, and contractors carefully .
adhered to the work order and procedure requirement .2 Turbine Driven Auxiliary Feedwater Pump Testing Maine Yankee operations personnel conducted testing of the Turbine Driven Auxiliary ;
Feedwater Pump (TDAFP) using the direct feed flow path to the steam generators (monthly j
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testing uses recirculating flow) as directed by station procedure 3.1.22, Emergency
, Feedwater System Cold Shutdown Flow Test. The auxiliary operator performing the i
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TDAFP lineup carefully adhered to the procedure, as did the reactor operator who ran the >
pump from the auxiliary shutdown panel. The operators found that the manual overspeed trip did not fall within the acceptance criteria specified in 3.1.22. They contacted the Plant Shift Supervisor (PSS), who reviewed test performance to that point. The PSS decided to repeat the test to confirm the initial results. At PSS direction the AO and RO retested with ]
similar result j
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The inspectors concluded that the AO and RO acted properly by taking action to involve the PSS. Despite the heavy workload in the control room as a result of activity associated with i the first day of a refueling outage, the PSS demonstrated an excellent focus on safety by his I direct involvement in the TDAFP tes .3 Emergency Diesel Engine Maintennnce The inspector observed the replacement of the 'B' emergency diesel generator (EDG)
turbocharger (WO 93-0616). This replacement wa'; necessary, per the manufacturer's recommendation, as a result of the January 1993 incident in which the diesel generator was motorized (see NRC Inspection Report 50-309/93-02). During the observed maintenance, the inspectors identified no performance deficiencies. The inspectors did, however, have several observations regarding the maintenance plan, including work procedure detail, quality control checks, and post-maintenance testin The inspectors noted that the licensee placed a large reliance on the vendor technical representative (MKW Power Systems), vice the use of detailed procedures, to ensure the turbocharger was replaced correctly. For example, the work order was not explicit on how i
to remove, prepare for installation, and install the turbocharger. Instead, the work order mainly referenced the technical manual and the guidance of the technical representative. The procedural steps necessary for the turbocharger changeout, as outlined in the technical manual, assumed a turbocharger failure had occurred.. Thus, several of the installation steps were not applicable. However, the licensee's work order did not ensure that certain procedural steps, such as an inspection of the gear train for nicks, burrs. or evidence of improper backlash, or inspection of the exhaust manifold, were completed prior to ;
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turbocharger installation. Instead, the licensee's work order relied solely on the vendor to select the necessary installation steps. The inspectors discussed this issue with the
maintenance supervisor who then ensured the necessary inspections were satisfactorily completed. The maintenance supervisor who monitored this activity, as well as several other j
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maintenance tasks in the plant, was satisfied with the technical representative's guidance and i
direction The inspectors also noted that the quality control (QC) checks within the work order could )'
have been improved. Although QC performed foreign material closecut inspections and torque verifications, no QC verification was specified for the turbocharger impeller eye clearance checks. The impeller eye clearance checks are a critical measurement used for indication of turbocharger distortion during installation. The technical representative ensured j 4 '
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this check was done; however, the work order did not provide for these measurements to be recorded. The post-maintenance testing requirements specified within the work order could also have been strengthened. The work order did not require that engineering personnel (plant engineering department) be present to monitor the diesel during its startup and load-run. Engineering personnel maintain a diesel reliability program and could monitor turbocharger performance (via vibration analysis) during the test run. Tdeninspectors discussed this with the responsible engineer who agreed that engineering personnel should monitor the post-maintenance testing. The work order was subsequently updated to incorporate engineering involvemen Overall, the turbocharger replacement was satisfactorily performed as a direct result of technical representative's guidance and direction. However, oversight of vendor activities in this area was wea .4 Emergency Diesel Generator Reliability and Condition Monitoring The reliability of EDGs is one of the main factors affecting the risk of core damage from a station blackout event. The Maine Yankee licensing staff maintains the reliability program, while the plant engineering department (PED) maintains a diesel condition monitoring program used to ensure high engine reliability. The licensee's reliability program was consistent with the guidance of Regulatory Guide 1.155, " Station Blackout," and NUMARC 87-00, Appendix D. No trigger values for start or load failures have been exceeded for the last 20,50, and 100 demands. The licensee's target reliability level of 0.975 has been satisfied, as only one failure has occurred in the last 100 demands. This is indicative of excellent EDG reliability. The licensee's reliability program also provides a means for failure evaluation, root-cause analysis, and corrective actions. The scope of the required failure evaluations is appropriately expanded depending on whether single or double trigger values are exceeded, or if a problem EDG is identified. No failures have occurred since the implementation of this progra As part of diesel reliability, the licensee performed trending analysis various EDG parameters from which maintenance actions may be determined. Licensee personnel also obtain trending data during operational surveillance testing at a minimum of every 3 month The inspector verified that for these dynamic measurements, the parameters were recorded consistently at the same load setting and after the engine has reached steady state condition The licensee's EDG (General Motors, Electro-motive Division, Model 645) has limited installed instrumentation for engine condition monitoring. For example, instrumentation for measuring crankcase vacuum is not available; therefore, the licensee is unable to trend for degradation and blowby of the piston compression rings. However, the licensee has taken the initiative to monitor other parameters via alternate rneans. For instance, a contact pyrometer measured individual cylinder exhaust temperatures, during the most limiting full-load condition of the engine. Cylinder exhaust temperature is one of the most important parameters to trend, as it provides a cumulctive view of the whole fuel injection system, combustion process, and valve phasing. The PED has also initiated a vibration analysis
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program for the diesel engine and generator. Although the technical manual does not provide baseline values or alert levels, the licensee's computer comparison program could alert engineering personnel to possible degrading conditions. Additional generic information exchange on EDG issues (reliability, performance, etc.) is obtained by the licensee's ;
corporate engineering staff as part of General Motors' owners groups within the nuclear !
industr l The licensee's maintenance department also maintains a trend of lube oil analysis and lube oil consumption. Spectrographic analysis of the lube oil is done every three months to identify various metallic and chemical compounds. The chemical analysis was consistent with the diesel technical manual with respect to compounds analyzed for and specification limits. No l adverse trends were identiDed by the inspector. The licensee monitors lube oil consumption to provide an indication of abnormal engine wea ,
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Overall, the inspectors considered Maine Yankee to have a viable diesel condition monitoring program so that precursor conditions can be identified prior to engine failure. This enhanced ;
monitoring, in turn, resulted in improved diesel reliability. The inspectors did note that no one cognizant individual is responsible for these programs. Thus, communication between ;
the various organizations (maintenance, licensing, corporate engineering, plant engineering)
is vital for ensuring proper diesel performance monitoring. In one case, the inspectors observed that the responsible plant engineer was not aware of baseline vibration data provided by MKW Power Systems to corporate engineering via the General Motors owners grou .5 Emergency Diesel Generator Preventive Maintenance
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The inspectors performed a review of the licensee's preventive maintenance (PM) program for the EDGs. The licensee recently revised this program in 1992 to more accurately reflect the manufacturer's recommendations. The inspector found the licensee's current program
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(scope and frequency of PMs) to be consistent with the diesel technical manual. One PM activity, crankshaft torsional damper inspection, had not yet been incorporated into the '
licensee's PM program. The inspector also reviewed the work orders (93-01826 and 93-00171) for the annual diesel engine internal inspections. Two PM tasks, piston ring inspection and fuel injector rack length check, were not included in these work order Maine Yankee informed the inspector that these checks were completed but not documented as the vendor technical representative and licensee mechanics were aware of the need to !
perform these inspections. The inspector also noted that the licensee's documentation of i inspection measurements was inconsistent due to a lack of clarity in the work orders. For ,
example, the lead wire measurement checks for piston head clearance for the 'B' EDG data were not properly recorded. This data, which was not recorded in the machinery history Die, could have been valuable for trending purposes. Maintenance personnel informed the i
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I inspectors that the Maintenance Department is in the process of revising these repetitive work ;
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orders. The inspectors reviewed a rough-draft version of the annual engine internal inspection procedure and noted potential improvements with respect to procedure detail, ,
scope, and documentatio j t
The inspector also reviewed the chemistry department involvement in diesel PMs. Fuel oil analysis is accomplished, as a minimum, on an annual basis and following a refueling outage in which fuel oil was delivered. The fuel oil specifications were consistent with those recommended by the manufacturer. The licensee appropriately uses a low sulfur (<0.5%) ,
content fuel that minimizes engine wear. The jacket water system continues to use chromates I as a corrosion inhibitor. An unusually high chromate concentration exists in the 'B' EDG :
(10,000 ppm) as a result of a calculation error for inhibitor addition in November 1991. The j licensee evaluated this condition as acceptable, as the manufacturer recommends a lower l limit of 3,000 ppm but no upper limit. The inspectors also verified that a glycol-water ;
antifreeze is not used in combination with the chromate inhibiter as this may result in an ;
insoluble sludge forming within the cooling syste ;
Overall, the inspector found the licensee's current diesel PM program to be consistent with the manufacturer's recommendations. Improvements to the PM program were evident following the licensee's review in 1992. Additional improvements to work order quality are warranted. The licensee's current actions to develop the diesel repetitive work orders to accurately reflect the details and specifications of the engine manual are appropriat .6 Degradation of Emergency Diesel Generator Output Voltage Relay On August 15, a Central Maine Power Company relay technician assigned to Maine Yankee, -1 in the process of calibrating undervoltage relays for nuclear safety 4160V Bus 6, discovered a loose part when he removed the cover for relay 59-DGlB. Upon an automatic initiation signal, this relay senses emergency diesel generator (EDG) DG-1B output voltage and provides an automatic close permissive for the EDG output circuit breaker. After the last refueling outage, Maine Yankee Engineering personnel determined that relays 59-DGl A and 59-DGlB were not part of the station calibration program and had scheduled them for calibration during the current refueling outage. At the time of this report was written, it is not determinate as to whether the relay was operable. The EDG would have been capable of starting and flashing the generator field, but the output circuit breaker would have closed at approximately 86% of required generator output voltage. The system is designed to close the output breaker at 90% of required voltage. Premature loading of the EDG at a lower voltage could potentially lead to the generator being incapable of properly accepting emergency load In addition, plant engineering personnel during investigation of this problem also identified a wiring deficiency with the voltage sensing relays for DG-1 A and DG-1B. These relays use a common return wire to complete their electrical circuit. If the wire inadvertently opened, both relays could become inoperable and be not capable of performing their intended safety j
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function. In this case, the EDGs would not automatically connect to the electrical safety busses on a loss of AC power. The EDGs could be manually connected to the emergency busses, but this condition would not meet the station's design criteria for starting an emergency safeguards pump within 30 seconds with a loss of offsite power to mitigate the effects of a loss of coolant accident. A Region I specialist inspector has investigated these ]
problems and his Endings are included in NRC Inspection Report 50-309/93-2 j ENGINEERING and TECIINICAL SUPPORT l
- Defective Overcurrent Trip Protection Device l I
As stated in the Maine Yankee Final Safety Analysis Report (FSAR), section 6.2.2.3, the i safety injection systems provide post accident cooling. Heat is removed from the safety l injection systems by primary component cooling (PCC) water and secondary component i cooling (SCC) water in the shell side of the residual heat removal (RHR) heat exchanger i The heat from the PCC and SCC systems is removed, in turn, by the service water system in the tube side of the PCC and SCC heat exchangers. The service water system transfers the heat to the ultimate heat sink. The 480 volt electrical system supplies electric power to the ;
service water pumps. The FSAR, section 8.3.1.4 states that the 480 volt system is an t ungrounded system. Grounds on equipment are annunciated in the control room without i affecting operation of the equipmen i On July 30, with the reactor shut down and reactor coolant system (RCS) temperature t 515 *F, a control room alarm sounded at 10:22 a.m., indicating a ground on 480 volt bus !
The circuit breaker for service water pump P-29D opened 10 seconds later. Operators ;
immediately started P-29C without incident. Electricians found no trip flags present on the j RMS-9 overcurrent protection device for the P-29D circuit breaker. The electricians did End a 74 device Dag, indicating a ground that actuated the annunciator. The electricians meggered the P-29D motor, and found no indication of a motor electrical fault. The electricians installed a spare 480 volt breaker to test run P-29D. At 1:45 p.m. the P-29D breaker tripped open due to a ground. Motor control center (MCC) 8B feeder breaker also ' l tripped open. Electricians reinspected P-29D and found no discrepancies. At 1:30 a.m. on l'
July 31, when a 480 volt ground alarm came in, operators and electricians traced it to the boric acid mix tank (BAMT) heater :
At the morning meeting on July 31, maintenance staff informed plant management that they had identified the cause of the P-29D trips. The ground on the BAMT heaters caused the RMS-9 overcurrent protection device to actuate, causing the P-29D and MCC-8B circuit i breakers to open. The operations manager had previously refused to release P-29B to j maintenance until maintenance identiGed the cause of the P-29D trips. When maintenance identified the ground on the BAMT heaters as the cause of the service water pump trip, and informed management that the BAMT heaters had been isolated, they agreed to release P-29B for maintenanc _ - -__
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l The inspectors questioned the service water pump operability, since a fault on a non-safety related electrical load had interrupted operation of a safety related electrical load (the service l water pump). The inspectors questioned Maine Yankee's basis for concluding that grounds l on other non-safety related equipment would not cause additional service water pump trip In response to the inspector questions, Maine Yankee determined that, under accident l conditions, the RMS-9 protective devices could render the post accident heat removal capability of the safety injection system inoperable. During a design basis accident, the Emergency Operating Procedures direct operators to place the containment recirculation fans cooling fans in operation under certain conditions. The containment recirculation fans are not safety related at Maine Yankee, and are not environmentally qualified. The 480 volt buses which supply electric power to the service water pumps also surgy the containment recirculation fans. As a result of the RMS-9 performance, Maine Yankee could not assure performance of the service water pumps under these circumstance l In addition, Maine Yankee considered the effect of the service water pumps on the Technical Specification requirement for core energy removal with the reactor shut down and fuel in the core. Maine Yankee implemented measures to minimize the risk of loss of core energy 1 removal capability by removing unnecessary non-safety related loads from the 480 volt I buses, insuring redundant service water pumps were available until the cavity was flooded, j and training operators on measures in response to a service water circuit breaker tri !
During a conference call between the NRC, Region I and Maine Yankee, the NRC concluded j that Maine Yankee had taken reasonable and appropriate measures to assure core energy remova From August 21 through 27, an NRC Region I inspector from the Division of Reactor Safety conducted a detailed review of the technical issues surrounding the RMS-9 defect and Maine Yankee's response to the defect. The findings of that inspection are documented in NRC ;
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Inspection Report 50-309/93-2 In summary, the inspectors noted that Maine Yankee aggressively pursued the immediate j cause of the service water pump trips, and conservatively retained redundant service water pump availability in excess of the Technical Specification 3.8 requirements. At the conclusion of the inspection period, Maine Yankee engineering personnel with assistance from the General Electric company representative, planned to test the RMS-9 devices to validate previous data and provide additional insights into the nature of the observed malfunctions. The inspector determined that Maine Yankee's actions to identify the root cause and provide resolution to this problem were appropriat .2 (Closed) Violation 50-309/92-021-001, Review of Design Basis Evaluation in December 1989, Stone and Webster Engineering Corporation (SWEC) completed an analysis of the heat removal capacity of the Maine Yankee Primary and Secondary Component Cooling Water (PCC and SCC) systems in response to a postulated Loss of
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l Coolant Accident. SWEC's analysis assumed that in the event of an accident, SCC flow was i isolated from non-safety related loads such as the main generator hydrogen coolers in order j to permit maximum cooling to the Residual Heat Removal System (RHR) heat exchanger l On December 13, 1992, during a plant startup, operators discovered that valve SCC-T-227, j which controls flow of the SCC to non-safety related loads, had excessive leakage when !
closed. The initial leakage was approximately 400 gallons per minute (gpm), which was ]
reduced to 225 by maintenance personnel. Engineering personnel performed an analysis that concluded the valve, and the safety-related components cooled by SCC, remained operable for SCC-T-227 leakage of not greater than 400 gpm for restricted Service Water i temperature ;
l Maine Yankee did not adequately verify the validity of the assumptions in the SWEC analysis. The SWEC analysis assumed zero leakage for SCC-T-227 in the closed positio SCC-T-227 was a Fisher 7600 series butterfly valve not designed to be leak tight in the l closed position. However, the revised engineering calculation based on the known history of l
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service water temperatures, concluded that it was very unlikely that the plant operated with insufficient SCC cooling capacity between December 1989 and December 13, 199 In response to the violation, Maine Yankee revised procedure 17-21-5, Engineering Calculations / Analysis. For design organizations other than Maine Yankee engineering or j
Yankee Nuclear Services Division, step 3.1.7 now requires engineering review of calculations to:
) Ensure that the inputs and assumptions for the calculations have a documented basis; Verify the inputs and assumptions are consistent with the plant configuration, as
applicable; I Consider any equipment limitations or performance requirements which may be implicit to the stated assumptions; If additional assumptions are identined, then these additional assumptions shall be documented and evaluated by the reviewing enginee In addition, Maine Yankee indicated that future engineering department meetings would stress the above changes to procedure 17-21- The inspector concluded Maine Yankee's corrective actions were appropriate to resolve the l issue. This item is close .3 (Closed) Unresolved Item 50-309/93-03-02, Diverse Scram System On March 15, 1993, Maine Yankee determined that the Diverse Scram System (DSS) had been inoperable for about 38 hours4.398148e-4 days <br />0.0106 hours <br />6.283069e-5 weeks <br />1.4459e-5 months <br /> as a result of technician error. The DSS, part of the Anticipated Transient Without Scram System (ATWS) provides automatic backup to the i reactor protection system to insert all control rods into the reactor on high pressurizer pressure. Maine Yankee management reviewed the occurrence and, using the guidance
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provided in procedure 1-26-6, concluded that three days should be allowed to restore DSS operability, beginning from when the DSS was rendered inoperable. Maine Yankee restored
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DSS operability within the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed by procedure 1-26- The inspectors determined that additional NRC review was required to determine whether the use of procedure 1-26-6 adequately insured ATWS reliability, as required by 10 CFR 50.6 Additional NRC review was also required to determine whether the lack of a functional DSS was reportable. A resulting NRC review determined that since there is no regulatory 5 position on the method for treating the loss of ATWS system functions, Maine Yankee's :
treatment of the loss of ATWS mitigation capability, as provided by procedure 1-26-6, was l an acceptable means of ensuring availability and operation of ATWS equipment. Additional >
NRC review also determined that inoperability of ATWS was not reportable in accordance .
with 10 CFR 50.73. This item is close l
- (Closed) Unresolved Item 50-309/91-24-02, Instrument Calibration On January 9,1992, inspectors determined that Maine Yankee had not calibrated the :
pressure instruments associated with the waste gas decay drums since 1971. Inspectors
, previously identified use of uncalibrated instruments in surveillances (NRC Inspection Report (
50-309/91-81 refers). As noted in the response to the Notice of Violation, Maine Yankee l reviewed the list of uncalibrated instruments to identify all uncalibrated instruments used in ,
surveillances to demonstrate operability of safety related equipment. Equipment which is i considered "important to safety" had not yet been assigned a calibration frequenc I Maine Yankee calibrated the waste gas decay drum instruments immediately after notification by the inspector. These pressure gages were added to procedure 6-03-4.1, Instrumentation l and Controls Preventive Maintenance, and assigned a calibration frequency. During ;
procedure reviews, Maine Yankee Operations personnel are now required to develop a list of ;
the instruments employed during procedure performance and submit this list to the I&C l Department for review. The I&C Department then determines if calibration is required and l how often for all the instruments. The licensee's actions to resolve this item are appropriate {
to resolve the issue. This item is close i PLANT SUPPORT 4 Radiological Controls R
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 radiologict.1 control procedures and 10 CFR 20 requirement i During the refueling outage, the inspectors observed health physics (HP) technicians aggressively pursuing the ALARA goals established by Maine Yankee management. Maine i
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Yankee has budgeted exposure for each Radiation Work Permit during the refueling outag '
The HP technicians have actively monitored worker success in meeting the goals, and, in some instances, have stopped work when the ALARA budget for thejob was about to be exceeded. In other cases, HP technicians helped to minimize exposure by reviewing good ,
HP practices with workers. For example, before workers lifted the reactor head from the !
vessel, the HP staff identified low dose waiting areas on the charging floor in containment, and insured that workers, not necessary to the head removal and inspection activity, exited containment until the reactor head had been removed from the charging floor. Maine ,
Yankee management took additional measures, for this outage, to attempt to reduce personnel
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contaminations. Television sets have been placed in the lunch room and at the containment :
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personnel hatch. A tape showing the proper method of removing protective clothing to i
, minimize contamination, played continuously on the television sets. Management concluded that availability of the tape in the lunchroom and at the containment hatch exit will reduce !
! the number of personnel contaminations through improved HP practice !
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The inspectors also noted a significant increase in HP management presence in the plant during this refueling outage. In addition, the plant manager directed managers from all !
departments to tour the plant on a daily basis. The plant manager instructed all managers to j observe radiation worker performance to identify poor work practices and areas for improvement. Plant exposure has been discussed daily at the two o' clock outage meeting, to !
insure that problem areas have been identified and addressed. The inspectors concluded that i Maine Yankee has implemented aggressive measures to reduce total exposure for the refueling outag .2 Security l The inspectors veriGed that security conditions met regulatory requirements, the requirements
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of the physical security plan, and complied with approved procedures. The checks included security staf6ng, protected and vital area barriers, vehicle searches and personnel identification, access control, badging, and compensatory measures when required. No .
discrepancies were identifie At the beginning of the inspection period, Maine Yankee shut down for refueling. The !
inspectors noted that security management implemented comprehensive measures to insure careful control of access during heavy traffic periods at the access control point. The inspectors observed the measures, and concluded that they were very effective. The i inspectors also noted that the security manager and the assistant security manager were
- typically present at the access control point during heavy traffic periods, assessing the i effectiveness of the implemented measures. The NRC previously noted that positive control of access during outages had occasionally been a weakness. The inspectors concluded that !
Maine Yankee's action to address the previously identified weakness demonstrated the ability
to take effective correction actio i i
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12 Employee Concerns Programi
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The senior resident inspector interviewed the Plant Manager to determine the adequacy of Maine Yankee's Employee Concerns Program as required by NRC temporary inspection module TI 2500/028. The results of the interview and the required information resulting information is included as Attachment A to this repor , ADMINISTRATIVE Persons Contacted During this report period, inspectors conducted interviews and discussions with various licensee personnel, including plant operators, maintenance tecimicians and the licensee managemen I Summary of Facility Activities
Maine Yankee operated at 80% power on July 28. On July 30 because of concerns ;
regarding excessive leakage on the No. 2 Reactor Coolant Pump seal and vibration on No. 2 i Reactor Coolant Pump, Maine Yankee shut the plant down one day before the scheduled eight week refueling outage was scheduled to begin. At the end of the inspection period, {
August 29, the plant remained in a refueling outag Other inspections conducted during this inspection period include engineering (50-309/93-21),
radiological controls (50-309/93-19), and NDE (50-309/93-13).
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' 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 identifie .4 Exit Meeting Inspectors periodically held meetings with senior facility management to discuss the inspection scope and findings. At the conclusion of the inspection, the inspectors also presented a summary of findings for the report perio During the inspection period the inspectors conducted backshift inspection on July 29, August 2, 5, 9,12,13,16,19, 20, 26, and 27 and deep backshift inspectic , on July 29, and 31, and August 7,14, and 2 !
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ATTACIIMENT A EMPLOYEE CONCERNS PROGRAMS PLANT NAME: Maine Yankee LICENSEE: Maine Yankee Atomic Power Company DOCKET #: 50-309 NOTE: Please circle yes or no if applicable and add comments in the space provide ;
' PROGRAM: Does the licensee have an empicyee concerns program?
(Yes g No/ Comments) Yes Has NRC inspected tne program? NO Report # N/A SCOPE: (Circle all that apply) Is it for: Technical? (Yes, No/ Comments) Yes Administrative? (Yes, No/ Comments) Yes Personnel issues? (Yes, No/ Comments) Yes Does it cover safety as well as non-safety issues?
(Yes n No/ Comments) Yes Is it designed for: Nuclear safety? (Yes, No/ Comments) Yes Personal safety? (Yes, No/ Comments) Yes Personnel issues - including union grievances?
(Yes g No/Conunents) Yes, the program covers personnel issues, however, a separate process for union grievances would direct union issues to union representative . Does the program apply to all licensee employees?
(Yes & No/ Comments) Yes bsue Date: 07/29/93 A_1 2500/028 Attachment
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' Contractors?
(Yes a No/ Comments) Yes
! Does the licensee require its contractors and their subs to have a similar program? ;
(Yes u No/ Comments) No Does the licensee conduct an er.it interview upon terminating employees asking ,
if they have any afety concerns? l (Yes a No/ Comments) The licensee conducts exit ir. .trviews for Maine Yankee employees. They do not ask terminating employees if the have any
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nuclear safety concerns. They are considering an addition to address nuclear safety concerns as a result of this surve : INDEPENDENCE: i What is the title of the person in charge? Plant Manager
, Who do they report to? The Plant Manager reports to the Vice President of ;
Operations. The ECP instructs workers to bring concerns to first line supervisors, then the responsible department manager, the other plant ,
managers or the Plant Manager, then the Nuclear Safety Engineering section j head, in that order. Workers are told to go directly to another department manager, the Plant Manager, or the NSE section head if they are not comfortable discussing an issue with their department supervisor or manage ;
i' Are they independent of line management? No, however, the workers have access to managers not in their immediate line management and the NSE section head. The NSE section head is not in the line management of anyone, with the exception of the NSE section personne l Does the ECP use third party consultants? N . How is a concern about a manager or vice president followed up? Concerns-about managers would be addressed by the Plant Manager. Concerns about a vice president would be brought to the company presiden ! RESOURCES: l What is the size of the staff devoted to this program? No staff is devoted exclusively to this program, i
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i Issue Date: 07/29/93 A-2 2500/028 AttachmqJu
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1 . What are ECP staff qualifications (technical training, interviewing i
training, investigator training, other)? The NSE staff is trained in the Human Performance Evaluation System and MOR l 1 REFERRALS:
- Who has followup on concerns (ECP staff, line management, other)?
Individual supervisors or managers receiving concerns are tasked with followup. A database has been devised to track concern CONFIDENTIALITY: Are the reports conGdential?
(Yes _qr No/ Comments) Yes i i Who is the identity of the alleger made known to (senior management, ECP staff, line management, other)? l l (Circle, if other explain) Possibly only to the NSE section head; this is based i l on the wishes of the person expressing the concern and need-to-know Can employees be: Anonymous? (Yes, No/ Comments) Yes Report by phone? (Yes, No/ Comments) Yes FEEDilACK: Is feedback given to the alleger upon completion of the followup? (Yes or No
- If so, how?) Yes, by direct comn:anication from the person receiving the concer . Does program reward good ideas? / t g ~ nrogram rewards good suggestions. Managers would sugg u:,e d , c 'mployee Suggestion Program where appropriate.
I Who, or at what level, makes the ;inal decision of resolution? The person expressing the concern decides. The person expressing the concern has ,
recourse to take the concern to a higher authority if not satisGed. The Plant l Manager decides in the event of difficult decisions (employee refuses to be l satisGed). ] Are the resolutions of anonymous concerns disseminated? Yes, lessons l learned r.re disseminated while protecting employee anonymit Issue Date: 07/29/93 A-3 2500/028 Anachment
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. Are resolutions of valid concerns publicized (newsletter, bulletin board, all hands meeting, other)? Yes EFFECTIVENESS: How does the licensee measure the effectiveness of the program? Employees formerly went directly to the NRC with concerns. The system is presently being used by employees; the licensee is not aware of dissatisfied employees going to the NRC, and concludes that the program is effectiv . Are concems: Trended? (Yes g No/ Comments) Yes, through use of a databas Used? (Yes or No/ Comments) Yes In the last three years how many concerns were raised? =6 . Of the concerns raised, how many were closed? All What percentage were substantiated? =75% How are followup techniques used to measure effectiveness (random survey, interviews, other)? Direct followup by person receiving the concer . How frequently are internal audits of the ECP conducted and by whom?
None have been done to date; management is considering use of an internal auditing grou ADMINISTRATION / TRAINING:
3 Is ECP prescribed by a procedure? (Yes g No/ Comments) N . How are employees, as well as contractors, made aware of this program l (training, newsletter, bulletin board, other)? The ECP is advertised on bulletin boards, posters, in handouts, through indoctrination training, and through Plant Manager meetings with plant employee .
ADDITIONAL COMMENTS: (Including characteristics which make the program ;
especially effective, if any.)
Characteristics which make the program effective include:
- Personal involvement of the Plant Manager and other managers (the Plant Manager devotes two weeks per operating cycle to meetings with workers on the ECP),
Issue Date: 07/29/93 A-4 2500/028 Attachment i
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- Direct contact of managers with workers,
- Management emphasis on the practicality of the ECP; the program benefits everyone because management awareness of problems is essential to resolving the problem NAME: TITLE: PIIONE #:
Charles Marschall/ SRI /(207) 882-7519 DATE COMPLETED:08/15/93
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Issue Date: 07/29/93 A-5 2500/028 Attachment