IR 05000254/1999003
| ML20205N962 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/09/1999 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20205N957 | List: |
| References | |
| 50-254-99-03, 50-254-99-3, 50-265-99-03, 50-265-99-3, NUDOCS 9904190260 | |
| Download: ML20205N962 (18) | |
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U. S. NUCLEAR REGULATORY COMMISSION REGION 111 Docket Nos: 50-254;50-265 License Nos: DPR-29; DPR-30 Report Nos: 50-254/99003(DRS); 50-265/99003(DRS)
Licensee: Commonwealth Edisen Company (Comed)
Facility: Quad Cities Nuclear Power Station, Units 1 and 2 Location: 22710 206th Avenue North Cordova, IL 61242 Dates: March 8 through March 12,1999 Inspectors: R. Westberg, Reactor Engineer, Rlli T. Tella, Reactor Engineer, Rlll C. Miller, Senior Resident Inspector Approved by: R. Gardner, Chief Electrical Engineering Branch ,
Division of Reactor Safety
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9904190260 990409 PDR ADOCK 05000254 M PDR 3,
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EXECUTIVE SUMMARY Quad Cities Nuclear Power Station, Units 1 & 2 NRC Inspection Report 50-254/99003; 50-265/99003 The primary focus of this inspection was to evaluate the program and procedures regarding maintenance of electrical power circuit breakers, to aesess corrective actions for previously - '
identified maintenance pr )lems, and to review long standing maintenance related materiel condition problem Maintenance
- The inspectors noted an improvement in reducing the backlog of overdue PMs; however, problems remain in the area of PM development and scheduling (Section M1.2).
- The inspectors considered '.he practice of writing problem identification form (PlFs) for all maintenance rule functional failures (MRFFs) a good practice because it provided another useful tool for trending performance (Section M2.1).
- Materiel condition for the majority of switchgear reviewed was adequate. Some previously identified conditions received low priority for repair, including water leaks near the switchgear and diesel generator exciter cabinet, cracked power leads, and leaks from the cubicle primary disconnects (Section M2.2).
- Longstanding and repetitive equipment problems were still affecting system performance. Some progress had been made in the area of improving reliability of reactor recirculation pump seals. However, repetitive equipment problems were noted with nuclear instrumentation, offgas system, condensate system, reactor core isolation cooling system, and with main steam line radiation monitors. In some cases previous plans from engineering were not followed or received low priority (Section M2.3).
- Based on our review of a sample of breaker related maintenance work orders, surveillances, Problem Identification Forms (PIFs), and action items for adequacy of circuit breaker maintenance, and satisfactory resolution of identified breaker issues, the licensee's breaker maintenance program appeared to be satisfactory (Section M3.1).
- The inspectors concluded that in general self assessments were thorough and sufficiently self critical (Section M7.1).
- The sample of trending PlFs reviewed were effective in documenting root causes of repetitive failures and implementing subsequent corrective actions (Section M7.2).
- The programs for refurbishment of medium and Icw power circuit breakers were acceptable and circuit breaker performance was acce'ptable (Section M8.1).
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< : The inspectors concluded that sufficient voltage would be' available to' perform needed :
safety related breaker openings and closures during a loss of offsite power (LOOP) or - .q
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LOOP and loss of coolant accident (LOCA) discharge of the battery for the control: j circuits reviewed (Section E2.1). However, the inspectors considered the lack of a ^
control power calculation for 480V breakers a weaknes .
. The inspectors' concluded that Information Notice 97-53, " Circuit Breakers Left Racked -
Out in Non-Seismically Qualified Positions," was adequately addressed regarding the -
seismic qualification of medium voltage switchgear. The calculations performed during the inspection relative to seismic qualification of 480V switchgear were found -
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acceptable (Section E2.2).
- The inspectors concluded that the two breaker system / component engineers interviewed were experienced and knowledgeable in the breaker areas (Section E4.1).
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11. Maintenance L
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.M1 - Conduct of Maintenance . 4 M1.1 General Comments in recent history, there were a series of problems and subsequent corrective actions'.
involving maintenance at Quad Cities. For example:
The Maintenance Rule Baseline Inspection, No. 50-254/97017(DRS); '
50-265/97017(DRS), in 1997, conchded that the maintenance rule program was not ,
adequately implemented. However, by 1998, the maintenance rule follow-up inspection, No. 50-254/98008(DRS); 50-265/98008(DRS), concluded that the program :
met all requirement inspection Report No. 50-254/97026(DRP); 50-265/97026(DRP), in late 1997,' identified problems with breaker maintenance including untimely corrective actions and failure to -
perform preventive maintenance. In May of 1998, the resident inspectors reported that numerous problems with 4.16kV circuit breakers were being identified, but they were .
being effectively tracked and repaired in a timely manner, inspection Report No. 50-254/98009(DRP); 50-265/98009(DRP), in early 1998, identified maintenance issues relating to re-work, overdue preventive maintenance, and materiel condition. Again, corrective actions were taken for these issue In all these cases, corrective actions were taken and appeared to be effectiv In general, the inspector's review included problem identification forms (PIFs), action requests, engineering requests, self assessments, root cause analyses, maintenance rule functional failure data, trending data, and performance indicators. In addition, interviews, plant walkdowns, and observation of breaker work in progress wer conducted. in the specific area of breaker maintenance, the inspector's review included maintenance rec 6rds, surveillances, and corrective work requests for selected 4.16kV and 480V electrical circuit breakers. In addition, the inspectors reviewed j
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follow-up actions for vendor technical bulletins, industry communications and NRC information Notices (ins) regarding electrical circuit breaker M1.2 Preventive Maintenance (PM)
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. Inspection Scope (62700)
The inspectors reviewed PM history, root cause analysis reports, and interviewed engineers relative to PM schedulin Observations and Findinas I 1 Previous problems with overdue PMs had been identified in Inspection Report N /265-98004(DRP). This report noted that from October 1996 to February 1998, -
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there were 157 PMs completed on time and 1,278 performed but overdue. Specific instances where safety equipment preventi/e maintenance tasks were overdue included nine Cutler Hammer 250Vdc breaker cubicle inspections which exceeded the prescribed 6-year frequency and twenty-one 480V General Electric (GE) breakers that had exceeded their 3-year PM frequency. Subsequently, the conclusions of the licensee's March 25,1998 root cause analysis on the trend of deferrals of PM were that there was a deficiency in the training and qualification of schedulers and a lack of station guidance on PM deferrals. Completion of training and implementation of a station policy led to performance improvement in reducing overdue PMs. During this inspection there were only three overdue PM The Inspectors found several examples of where PM items were not scheduled for correcting problems. For example, maintenance items to ensure valves in the condensate system were in good working order were developed about two years ago by the system engineer, but many were not accomplished, partially because of low priority. Further, the station has been developing predefined maintenance items on a component basis using an Electric Power Research Institute template. Air operated valves have been entered into the electronic work control system using these templates but Solenoid operated valves have not. The corporate performanced centered maintenance program is working to addrecs the issue of PM development and scheduling at Quad Citie Previous problems with failure to develop and complete PM tasks for the station blackout diesel generators had been noted in inspection report No 50-254/265-9800*0RP). During this inspection, the inspectors verified that most preventive tasks were scheduled, and completion of the tasks were current. However,20 of the 545 items had not yet been assigned a frequency for completion, and therefore had not been scheduled. Licensee engineers corrected this and assigned appropriate frequencies and due dates after the inspectors discussed the discrepancy with the l The inspectors noted significant licensee efforts underway, primarily on Unit 2, to j improve the Feedwater Control System which had been responsible for several reactor i vessel water level transients in the last 6 months. However, periodic replacement of {
aging electronic components had not been fully addressed. Some components which !
should have been identified for periodic replacement due to aging had not been identified with a predictive maintenance task. The system engineer indicated these items would be adde ;
c. Conclusions The inspectors noted an improvement in reducing the backlog of overdue PMs; l
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however, problems remain in the area of PM development and schedulin ;
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M2 Maintenance and Materiel Condition of Facilities and Equipment M2.1 Review of Maintenance Rule Functional Failures (MRFFs) Inspection Scope (71707)
l The inspectors reviewed a list of repetitive MRFFs for the past two years and selected a sample for further revie Observations and Findinas )
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The list of MRFFs was generated from the PIF system. The inspectors considered the j practice of writing a PIF for all MRFFs a good practice because it provided another i
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useful tool for trending performance .
The inspectors requested additional information relative to MRFFs on the 1 A turbine ;
building component cooling water pump, U2 back draft dampers, mispositioning of the j
% emergency diesel generator (EDG) cooling water power selector switch, and the r U1 EDG time delay (TD2) relay. After a series of discussions with licensee engineers, all questions raised by the inspectors were satisfactorily answere Conclusions The inspectors considered the practice of writing PlFs for all MRFFs a good practic M2.2 Medium and Low Voltaae Switchaear Walkdown Inspection Scope (71707)
Inspectors walked down the majority of 4.16kV switchgear and portions of 480V and lower voltage busses and motor control center Observations and Findinas in general, the majority of switchgear was sdequately maintained. Materiel condition discrepancies were identified by work requests, with some exceptions. The inspectors also identified some uncorrected conditions which had been previously identified by PIF No. Q1999-00797. These issues included labeling problems, missing charging motor switch covers, missing manual charging covers, and other issue Other minor problems identified by the inspectors included: Water leaks were observed above the safety related 4.16kV bus 14- Inspectors observed active leakage from plant heating steam piping into and around three catch basins above the switchgear, and some water on the floor near the switchgear. This was a continuing maintenance problem which had not yet been resolved. Work Request 990012982 was written in early 1999 to address the problem, but no scheduled work date was known at the time of the inspectio . The inspectors also observed signs of water leakage above the % emergency diesel generator exciter cabinet. A waterproof tarpaulin was draped over the top of the cabinet in a manner which would divert water intrusion from abov The inspectors found no work request to address the potential water leaks. In later discussions with the shift operations supervisor, the inspectors learned that snow had penetrated through the air intake dampers which were located above the exciter cabinet. No work request was in place to address the snow intrusion. The licensee initiated action request 990016789 to address the issu . Some 480V breakers continue to have problems with the Jacking screw collar not disengaging. Bus 18, cubicle 3B, had an action request to repair the colla This was corrected by March 11,1999. The inspectors observed signs of denting and paint chipping on several other 480V breakers in the vicinity of the collar device which was indicative c' problems with collar operation. Problems with collars sticking have occurred in the past and caused equipment such as an emergency diesel generator cooling water pump to become inoperabl Procedural controls had been implemented to address this proble . Work requests for some breaker isst es appeared to exist for long periods without corrective actions being taken. For example:
- Some leakage of fluid at primary disconnects was still occurring at the non-safety 4.16kV switchgear. Busses 11,12,21 and 22 all had indications of leaking pitch from the cubicle primary disconnects. The licensee had written work requests to repair the leaking disconnects, but in some cases the work was scheduled for over three years awa Engineers indicated the possibility for the pitch to cause arcing problems was sligh Alignment for a problematic feed pump breaker was scheduled for 17 months after the action request was writte l
- Cracked power cables for Bus 19-1 Cubicle H2 were identified in November 1998, and not scheduled for repair until May 199 . Inspectors found that bus 23 had a larga amount of dirt and debris on top of the cubicles, some of which was adjacent to ventilation openings for the bus. The bus cleaning PM was past the 10 year due date. The licensee issued Action Request 990016768 after the breaker walkdown in order to correct the proble . Minor botting discrepancies were observed which were not marked by work requests. The licensee issued work requests to address the discrepancies.
c. Conclusions Materiel condition for the majority of switchgear was adequate. Some previously identified conditions received low priority for repair, including water leaks near the switchgear and diesel generator exciter cabinet, cracked power leads, and leaks from the cubicle primary disconnect l
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M2.3 Lonastandina and Repetitive Eauipment Problems Inspection Scope (71707)
The inspectors reviewed materiel history of past equipment failures, and interviewed engineers relative to corrective actions for repetitive equipment problem Observations and Findinas The inspectors reviewed electronic work control system reports, PlFs, and system engineer summaries of problem areas. In some cases, the inspectors found that histories of known equipment failures were either not in the electronic work control system or not easily retrievable by station employees. For example, numerous failures of control power transformers on 480V switchgear were not found in the electronic work control system by maintenance workers, but in several cases were located by the inspectors using PIF historie Pump vibration problems for equipment in the scope of the in-service testing program included the 2B residual heat removal service water pump, the safe shutdown makeup pump and the Unit 2 high pressure coolant injection pump. The licensee attempted to repair the safe shutdown makeup pump on the week of March,15,1999. Just before the work was to start, parts problems were identified which precluded the replacement of the rotating assembly. The licensee attempted to align the 2B residual heat removal service water pump on the week of March 22,1999. The first attempt was unsuccessful, and the pump remained in the alert range. The second attempt was successful in restoring the pump to normal vibration level l
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The inspectors found that the licensee had recently taken significant steps to minimize problems with reactor recirculation pump seals. Previously seals were changed out at least once per refueling cycle, and in some cases up to three times per cycle because of failures. The licensee just completed the change out of the last reactor recirculation pump seals on unit one with a new "N" type seal which has a significant increase in life expectancy. All reactor recirculation pump seals for both units were of the new design following this chang ,
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Some systems which continued to exhibit high failure rates or repetitive maintenance were identified below:
Intermediate Ranae Nuclear instruments: Numerous spiking problems had occurred in the last 2 years. Licensee engineers and General Electric (GE) i representatives found copper migration to be a cause of much of the spiking !
with some detectors. The licensee began replacement with a detector type which was not expected to be susceptible to copper migration, but this process j was expected to take several years because replacement would occur as the i old detectors faile l Condensate System: Many problems with condensate had been addressed in the last three years including change out of most filters with an improved i design. However, the station lost track of some priorities the system engineers I had developed several years ago, such as air operated valve replacements and
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modifications to the feedwater booster pump minimum flow valve controls.
Condensate demineralizer problems continued. After 2 events in 1992, engineers developed a plan to change out dual action solenoid valves which were drain valves for the condensate demineralizers. Another draining event which flooded the condensate pump area in 1994 ws. caused by a different air operated valve failure. An engineering exempt change was initiated in 1994 which would have changed dual action solenoid valves, which were prone to failure, to single action solenoid valves. Later, engineers canceled the exempt change and planned to accomplish the task with a parts replacement which was generated in 1995. Most, but not all the dual acting valves were changed out by 1998. One that was not changed was responsible for a near loss of feed event on March 6,1999, which opened a drain path from the condensate system and dumped about 25,000 gallons of water into the backwash receiving tank and then onto the condensate pump floor area. This was documented in PlF No. Q1999-00852.
Offaas and Hydrcaen Recombiner Systems: Inspec' ors found continuing problems with fires in the offgas system upstream ot the recombiner. Offgas fires had occurred several times in the last 3 months, and as recently as February 17,1999. System engineer plans from several years ago to restore the use of both recombiner trains in both units were not continued after the system engineer left the station. Recent management initiatives began making this, as well as restoration of offgas trains for both units, a priority again.
Control Rod Drive Pumos: These pumps remained a high maintenance problem, and a significant rework concern. Problems with the 2A pump in December 1998 caused a fire when a bearing overheated and ignited oil in the i
reservoir. The pump was rebuilt, and failed again by February 26,1999, after less than 400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> of oneration. Root cause teams were ir,itiated in both cases; however, at ti,e ..id of the inspection no root causes had been identifie '
The 2A pump had been rebuilt 5 times since1996. The four control rod drive pumps had been rebuilt a total of 24 times since 1986. Subsequent to the on-site portion of this inspection, on March 17,1999, high vibrations were noted again on the 2A pump, and the station took the pump out of use untilit could be rebuilt again.
Main Steam Line Radiation Monitors: The inspectors reviewed history for the main steam line radiation monitors. Work requests showed a high level of maintenance activity on these components and the chassis for the monitors 2 owed a high rate of replacement. Spiking on these instruments was the ,
cause for a number of partial group 1 primary containment isolation signals and !
partial reactor trip signals. Several of these spiking events including at least two l in 1998 had the cause listed as unkr own. Low voltage power supplies were l identified as a cause of some detector downscale signals. The vendor had recommended replacement of these power supplies at 5 years. The inspector reviewed the replacement history and found that monitors had low voltage power supplies which exceeded the 5 year replacement frequency. In addition, two steam jet air ejector monitors, which have the same low voltage power supply, were overdue for a 5 year replacement. System engineers issuad an i
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action plan to correct some of the problems with main steam line monitors on March 22,190 Reactor Core isolation Coolina: The reactor core isolation cooling system was
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identified with leakage back from the reactor which pressurized the suction piping. Planned outage Q2P01 included work to fix this problem, including repsirs to the Unit 2 reactor core isolation cooling 49 and 50 valves as a means to prevent the leakage into the suction piping. Following the planned outage, leakage continued into the system, which pressurized the suction pipin Conclusions Longstanding and repetitive equipment problems were still affecting system performance. Some progress had been made in areas such as improving reliability of reactor recirculation pump seals. However, repetitive equipment problems were noted with nuclear instrumentation, offgas system, condensate system, reactor core isolation cooling system, and with main steam line radiation monitors. In some cases previous plans from engineering were not followed or received iow priorit M3 Maintenance Procedures and Documentation M3.1 Review of Past Maintenance Work on Electrical Circuit Breakers Inspection Scope (62700)
The inspectors reviewed a sample of breaker related maintenance work orders, surveillances, PlFs, and action items, to evaluate whether the licensee's past maintenance of circuit breakers was adequate to assure satisfactory performance, and whether previous breaker related problems were satisfactorily resolve Observations and Findinas The inspectors reviewed several breaker related maintenance work orders and surveillances, to evaluate whether the licensee's past maintenance of the circuit breakers was adequate to assure their satisfactory performance. The inspectors also reviewed several breaker related PlFs, action items and completed corrective actions to evaluate whether the licensee had satisfactorily resolved the previously identified breaker issues. The inspectors noted that there was no documer:tation available to show whether minimum voltage tests were performed by the vendor on 480V breakers, in accordance with industry recommendations. The minimum voltage tests would help in trending the breaker performance and to indicate sluggish operating mechanisms and/or hardened grease.1he licensee was aware of these recommendations, but had not yet performed these minimum voltage tests on the 480V breakers. However, these tests had been performed by GE during off-site refurbishment of the 4.16kV breaker The licensee had also initiated these tests for 4.16kV breakers during maintenance at the sit Recently problems had been identified on Merlin-Guerin 4.16kV breakers. These problems included loose wires, trip tube damage, and cracking of phenolic materia The inspectors noted that seven PlFs were issued in 1998 regarding the cracking of
phenolic material. The inspectors were concemed that the cracked chips of phenolic material could lodge in the breaker components that could affect the breaker operatio The inspectors also noted that when a breaker failed to operate, it was replaced and sent out for refurbishment. As mentioned in Section M8.1, the vendor refurbishment reports for several breakers did not include all relevant "as found" data. In view of this, it would be difficult to track and trend breaker failure histor Conclusions Based on the review of a sample of breaker related maintenance work orders, surveillances, PIFs, and action items for adequacy of circuit breaker maintenance, and satisfactory resolution of identified breaker issues, the inspectors concluded that the licensee's breaker maintenance appeared to be satisf actory.
M7 Quality Assurance in Maintenance Activities M7.1 Mair.tenance Self-Assessr " Inspection Scope (62700)
The inspectors reviewed a sample of self-assessment reports related to maintenanc Documents reviewed are listed at the end of this repor Observations and Findinas The inspectors reviewed the 1998 and 1999 maintenance self assessments on circuit breakers, materiel condition, foreign material exclusion, procedural adherence, and schedule adherence in general, the self assessments were thorough and appeared to be sufficiently self critical. The inspector's review of the Quad Cities Nuclear Power Station 1998 Circuit Breaker Assessment report produced one concem. The assessment identified some significant weaknesses such as lack of degraded voltage calculations, absence of testing to determine as-found condition of circuit breakers, lack of trending of component failures and lack of timely training of electricianc performing circuit breaker maintenance. Corrective actions for these weaknesses had been implemented and completed with the exception of degraded voltage calculations (See Section E2.1). In addition, the inspectors determined that the assessment report did not address seismic qualification of low voltage switchgear with circuit breaker removed from their switchgear cubicles. (Corrective actions for this issue are documented in Section E2.2 of this report.) Conclusions The inspectors concluded that, in general, self assessments were thorough and sufficier.tly self critical; however, the lack of seismic qualification of low voltage circuit breaker removal from switchgear cubicles was not found during the July 1998 self-assessment of circuit breaker .
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{ M7.2 Corrective Action and Trendina l Inspection Scope (62700) ~
The inspectors reviewed' a sample of trending PIFs and effectiveness reviews for--
previously identified corrective actions related to maintenance. Documents reviewed are listed at the end of this repor Observations and Findinos The sample of trending PIFs reviewed were effective in documenting root causes of repetitive failures and scheduling and implementing corrective actions.- Effectiveness" reviews were appropriately scheduled, with one exception. The scheduled effectiveness review date of January 28,2000 for Trend Report No. 254-230-98-SCAQ000017. " Rework Because of Leaks",' dated February 4,1999, appeared to be -
scheduled too far out in time to be useful in arresting the identified trend. The inspectors questioned the long period of time between taking the corrective actions and
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the subsequent effectiveness review. The inspectors were informed that the date had been set by procedure based on the date of the last corrective action, leaks due to parts issues (July 7,1999). Since the procedural requirement for effectiveness reviews was three to six months after completion of corrective actions, the date had been set at ..
six months hence. Subsequent to the end of the inspection, the inspectors were informed that the effectiveness review date had been moved forward by three months -
to September 15,1999, by NTS No. 98SCAQ0001701E Conclusions The sample of trending P: s reviewed were effective in documenting root causes of repetitive failures and implementing their subsequent corrective action M8 Miscellaneous Maintenance issues M8.1 Refurbishment Of Electrical Circuit Breakers Inspection Scope (62700)
The inspectors reviewed the programs for periodic refurbishment of electrical circuit breakers, Observations and Findinos The inspectors reviewed vendor recommandations regarding periodic refurbishment of .
their circuit breakers and determined that GE recommended breaker refurbishment once every 5 years while the licensee had evaluated their breaker performance history and concluded that a refurbishment once in 10 years was adequate. However,:
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performance problems related to breaker refurbishment were identified in inspection Report No. 50-254/97026(DRP); 50-265/97026(DRP). This report documented that 1 planned corrective actions to replace safety-related breakers with refurbished breakers -
were not completed in a timely manner for all breakers despite evidence of breaker grease stiffening due to age hardening.' Some preventive maintenance actions
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recommended by the breaker vendor were not performed. In some cases, breakers had not been overhauled for 28 years, even though they were known to contain grease susceptible to age hardenin The inspectors noted that currently, all the 4.16kV breakers, except for Bus 14-1, had been replaced with new Merlin-Guerin breakers and the GE 4.16kV breakers in Bus 14-1 were recently refurbished. These breakers are currently performing satisfactoril i The 480V GE breakers in the plant were about 30 years old. They were refurbished once, about 11 years ago. These breakers were currently due for refurbishment and {
had been scheduled. In genera!,480V breakers have been performing satisfactorily; however, several breaker failures occurred recently These included the 1A reactor protection system (RPS) motor-generator set failure to start on March 11,1999 and the
% "A" starting air compressor breaker trip on March 15,1999. Root causes for these breaker failures were not known at the end of the inspection. Subsequent to the on-site portion of the inspection, the root cause of the 1 A RPS motor-generator failure to !
start was determined to be improper breaker setting, not a breaker failure. The root cause of the % "A" starting air compressor breaker trip was determined to be a bad pressure switch, again, not breaker failur The inspectors noted that the previous GE refurbishment reports on some 480V breakers did not include all"as found" data on the breakers such as lubrication data, acceptance criteria for Megger readings, and reasons for replacement of parts. Lack of breaker as-found data will make it difficult to trend breaker failures. The licensee informed the inspectors that the purchase order to GE was being revised to include a j requirement that "as found" data would be included in the refurbishment reports c. Conclusions The programs for refurbishment of medium and low power circuit brera... were acceptable and currently circuit breaker performance was acceptable. Lack of breaker as-found data in previous GE refurbishment reports for 480V breakers will make future trending of breaker failures difficul ]
Ill. Engineerina E2 Engineering Support of Facilities and Equipment .
E2.1 Control Power for Electrical Circuit Breakers j l
a. Inspection Scope (6270_0_) I
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The inspectors reviewed calculations to determine whether satisfactory circuit breaker operation was assured at a minimum control power operating voltages available during accident condition _ __
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. Observations and Findinas The licensee's breaker program self-assessment, completed in July 1998, identified that the 4.16kV breaker direct current (DC) control power calculation had not been updated with the current 125Vdc minimum battery terminal voltages expected during a loss of offsite power (LOOP) or LOOP and loss of coolant accident (LOCA) event. In addition, a minimum expected DC control power calculation did not exist for the 480V breakers. in response, the licensee issued evaluation NDIT No. ElC-99-001, dated March 5,1999, " Evaluation of 125VDC Voltage for 4.16kV and 480V Switchgear Operation." The inspectors reviewed the evaluation and determined that sufficient vchage would be available to perform needed safety related breaker openings and closures during a LOOP or LOOP and LOCA discharge of the battery. The licensee stated that the existing DC control power calculation No. 9149-20-19-1, Revision 4, would be revised and any additional calculations would be performed to address other control power issues. Nuclear Tracking System (NTS) Item No. 254-250-99-09513.01 was issued by the licensee to track updating of the calculation and the review of other control power issue Conclusions The inspectors concluded that sufficient voltage would be available to perform needed safety related breaker apenings and closures during a LOOP or LOOP and LOCA discharge of the battery for the control circuits reviewed. However, the inspectors considered the lack of ri control power calculation for 480V breakers a weakness.
E2.2 Seismic Qualification of Power Circuit Breakers Inspection Scope (62700)
The inspector reviewed the licensee's actions to maintain seismic qualification of safety related circuit breakers with some breakers completely removed from the switchgear cubicle I Observations and Findinas The NRC issued Information Notice 97-53, " Circuit Breakers Left Racked Out in Non-Seismically Qualified Positions," on July 18,1997, regarding circuit breakers left racked out in non-seismically qualified positions. The IN stated: "It should be noted that removal of the circuit breaker from the switchgear will result in mass redistribution of the switchgear. Mass redistribution of the switchgear may then change the frequency of the switchgear and its dynamic response during a seismic event and may invalidate the original seismic qualification of the switchgear. Therefore, the situation l must be evaluated to ensure that the removal of the circuit breaker will not invalidate I l
the original seismic qualification of the switchgear."
The inspectors inquired whether the licensee had evaluated the effect of the removal of some circuit breakers from their switchgear cabinets on the operability of the remaining safety related breakers in the cabinets. The licensee produced calculation No. QDC-6700-S-0794, Revision 0, dated March 6,1999, " Seismic Qualification of 4kV Switchgear with Breakers in Test Position or Removed." This calculation, based on l
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seismic tests conducted earlier on Pacific Breaker Systems Inc. 4.16kV breakers, concluded that: (1) the switchgear and relays remain seismically qualified when up to 50% of the switchgear cubicles in any single switchtjear bus lineup have breakers in the Test position; and (2) the switchgear and relays remain seismically qualified when up to 2/3 of the switchgear breakers are remove The licensee concluded that these results were applicable to both GE and Merlin-Guerin 4.16kV breakers. The inspectors noted that the results of this calculation were not yet translated into applicable plant procedures. The licensee issued an NTS item No. 254-250-99-03201 on March 9,1999, to revise the applicable plant operating procedures, to include the limitations as shown abov The licensee stated that no previous seismic test results were available for 480V switchgear, as Quad Cities was a Seismic Quaiification Utility Group (SQUG) plan After a further inquiry by the inspectors, the licensee issued calculation No. QDC-7100-S-0799, Revision 0, dated March 11,1999, " Seismic Oualification of 480V Switchgear with Removed Breakers." This calculation concluded: "This equipment is original equipment supplied by GE and is under the Seismic Qualification Utility Group (SQUG) Program. The guidance provided by SQUG, the results of the SQUG Program and calculations herein prove that removal of any combination of or all circuit breakers does not adversely affect the results of the SQUG Program. The calculation shows that the new frequency of the switchgear unit remains in the region where the demand is enveloped by the capacity. Therefore, the SQUG evaluations and conclusions remain valid for this condition of all breakers removed and for all intermediate conditions of one or more breakers removed, which addresses the concern of the Information Notice."
Subsequent to the on-site portion of the inspection, the inspectors reviewed this issue further with Region ill mechanical engineers and consulted with the office of Nuclear Reactor Regulation. The calculations performed during the inspection relative to the seismic qualification of the 480V circuit breakers were found acceptabl c. Conclusions The inspectors concluded that Information Notice 97-53, " Circuit Breakers Left Racked Out in Non-Seismically Qualified Positions,"was adequately addressed regarding the seismic qualification of medium voltage switchgear. The calculations performed during the inspection relative to seismic qualification of 480V switchgear were found acceptabl E4 Engineering Staff Knowledge and Performance E4.1 System Enaineer Interviews a. Scope of Inspection (62700)
The inspectors interviewed two system / component engineers involved with electrical circuit breaker .
4 . Observations and Findinos The inspectors interviewed two system / component engineers for 480V and 4.16kV electrical breakers and determined that the engineers were experienced and knowledgeable in the breaker areas. Both engineers exhibited knowledge of the breaker problems and about the implementation of Maintenance Rule in the breaker area Conclusions The inspectors concluded that the two breaker system / component engineers interviewed were experienced and knowledgeable in the breaker area V. Manacement Meetinos X1 Exit Meeting Summary The inspectors presented the inspection results to members of licensee mar;sgement near the conclusion of the inspection on March 12,1999. The licensee acknowledged the inspection results presente <
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PARTIAL LIST OF PERSONS CONTACTED Licensee Commonwealth Edison Company (Comed)
E. Anderson, RP Manager J. Dimmette, Site Vice { President
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T. Fd.8, Regulatory Assurar'ce L. Pearce, Station Manager J. Purkis, System Engineering Manager-D. Wozniak, Engineering Manager U, S. Nuclear Reoulatory Commission D. Roth, Resident inspector, Dresden INSPECTION PROCEDURES USED IP 62700 Maintenance Observations LIST OF ACRONYlmS AND INITIALISMS USED
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CFR Code of Federal Regulations EDG Emergency Diesel Generator GE General Electric IN Information Notice ,
LOOP Loss Of Offsite Power J LOCA Loss Of Coolant Accident MRFF Review of Maintenance Rule Functional Failures NTS Nuc, lear Tracking System )
PM Preventive Maintenance '
PDR Public Document Room PlF Prcolem identification Form l SQUG Seismic Qualification Utility Group WR Work Request
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PARTIAL LIST OF DOCUMENTS REVIEWED Work Request No. 9900 4424-01, "B11-21 Breaker Failed to Close" 1998 Circuit Breaker Assessment Final Report, July 21,1998 Maintenance Self Assessment 98-05, Materiel Condition i Maintenance Self Assessment 98-06, Foreign Material Exclusion (FME) I l
Maintenance Self Assessment 99-01, Schedule Adherence and Maintenance Work Schedule l
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Procedure Maintenance Self Assessment 99-02, Pracedure Adherence Trend Report 254-230-98-CAQ00023, Offgst. .i2 Analyzer issues Trend Report 254-230-98-SCAQ00017, Rework Because of Leaks Trend Report 254-230-98-SCA000003, EDG Start Failures Calculation No. QDC-6700-S-0794, Revision 0, "Setmic Qualification of 4kV Switchgear with Breakers in Test Position and Removed" Calculation No. QDC-7100-S 07Q9, Revision 0, " Seismic Qualification of 480 Volt Switchgear with Removed Breakers" Information Notice 97-53, " Circuit Breakers Left Racked Out in Non-Seismically Qualified Positions" i
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