IR 05000456/1994021
| ML20149G644 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 10/06/1994 |
| From: | Miller L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20149G624 | List: |
| References | |
| 50-456-94-21, 50-457-94-21, NUDOCS 9410240070 | |
| Download: ML20149G644 (13) | |
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U.S. flVCLEAR REGULATORY COMMISSION REGICfl III Report Nos. 50-456/94021(DRP); 50-457/94021(DRP)
Docket Nos. 50-456; 50-457 License Nos. NPF-72; NPF-77 Licensee:
Commonwealth Edison Company
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Opus West III 1400 Opus Place Downers Grove, IL 60515 Facility Name:
Braidwood Station, Units 1 and 2 Inspection At:
Braidwood Site, Braceville, Illinois Inspection Conducted: August 9 through September 16, 1994 Inspectors:
S. C. Du Pont E. R. Duncan C. E. Brown J. Roman Approved By:
k hC Ldyis F. Miller, fr./ Chief Date
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Reactor Projects Section lA Inspection Summar_.y Inspection from August 9 through September 16, 1994 (Report Hos. 50-456/94021(DRP): 50-457/94021(DRP))
Areas Inspected: Routine, unannounced safety inspection by the resident inspectors of the following activities:
Operational Safety, Plant Support, Maintenance, Surveillance, licensee action on previously identified items, and licensee reports.
Results: One violation with seven examples concerning the licensee's failure to comply with governing procedures is discussed in paragraphs 3.2, 4.1 and 5.0.
9410240070 941006 PDR ADOCK 05000456 G
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OETAILS 1.0 Management Summary The inspectors met with the licensee representatives during the inspection period and at the conclusion of the inspection on September 16, 1994.
The inspectors summarized the scope and results of the inspection and discussed the likely content of this inspection report.
The licensee acknowledged the information and did not indicate that any of the information disclosed during the inspection could be considered proprietary in nature.
1.1 Operations:
Weaknesses While securing the 2C condensate / condensate booster pump, the nuclear station operators did not perform the governing procedure as written and did not directly inform supervision and receive guidance from supervision as required by BwAP 100-20, " Procedure Use and Adherence." This is an example of a violation (50-456/94021-01(DRP);
50-457/94021-01(DRP)).
On August 19, while ramping up following a reactor startup, the heater drain tank (HDT) rupture disc failed.
Subsequently, the inspectors discovered that the rupture disc had become wetted during the previous startup, that rupture discs historically fail when wetted, and that system engineering had expressed some concern over the integrity of the rupture disc to the operations staff prior to the failure.
This is an unresolved item pending further NRC review (50-456/94021-01).
Strengths The licensee's response to an August 11, 1994, inadvertent MSIV
closure and reactor trip was excellent. Coordination between the operations and system engineering departments was effective and resulted in the identification of the root cause of the failure.
The operations department response to concerns that the steam generator safety valve may have lifted prematurely was conservative and demonstrated an excellent focus on safety.
On August 14, Unit 1 was restarted with no deficiencies noted.
1.2 Maintenance:
Weaknesses During new fuel transfer evolutions, the inspector observed several cleanliness procedure violations associated with BwFP FH-31, " Fuel Handling Cleanliness Zones and Requirements." These deficiencies included problems associated with control of
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personnel, entry postings, and procedure availability. This is an example of a violation (50-456/94021-01(DRP);50-457/94021-01(DRP)).
Poor ~ communication by the maintenance department to the operations
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department resulted in an unplanned minor power excursion..The inspectors reviewed the licensee's data and determined that the maximum average nuclear power during the transient was 101.28-percent and that no regulatory limits were exceeded.
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inspectors determined that although-a troubleshooting briefing was held prior to the maintenance, the electrician involved exceeded
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the scope of the actions discussed.
1.3 Plant Support:
Weaknesses On August 30, 1994, two electricians who entered the radiologically protected area (RPA) failed to read and understand the postings at the RPA entrance and obtain secondary dosimetry as required by BwRP 5000-7, " Unescorted Access To and Conduct In-Radiologically Posted Area." This is an example of a violation (50-456/94021-01(DRP);50-457/94021-01(DRP)).
During the inspection period, the licensee discovered multiple examples of contaminated material located outside the RPA in areas not posted as contaminated'as required by BwRP.5010-1,
" Radiological Posting and Labeling Requirements." These items included an eddy current cover plate discovered in a warehouse, reactor cavity decontamination paint containers and chairs discovered in the station laborers office, a 55. gallon drum
. discovered outside the site engineering and construction (SEC)
warehouse, and a scaffolding knuckle discovered in the turbine building.
In the previous two months, numerous similar examples have been identified.
Licensee corrective actions to control storage of contaminated material has'been ineffective.
These events are an example of a violation (50-456/94021-01(DRP);
50-457/94021-01(DRP)).
2.0 Operational Safety Verification (IP 71707)
The inspectors verified that the facility was being operated in
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conformance with the licenses and regulatory requirements and that the licensee's management control system was effectively carrying out its i
responsibilities for safe operation. The following activities and events are discussed below:
2.1 Unit 1 Trip and Steam Generator Safeties Actuation 2.1.1 Event Description
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On August 11, 1994, Unit 1 tripped from 100 percent power.
The unitLreceived an "A" train main steam isolation signal with
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subsequent closure of_all Main Steam Isolation Valves (MSIVs).
The closure of the MSIVs resulted in steam generator'(SG) level shrink and a reactor trip signal on low-low SG level.
During the transient, all equipment and. systems, except one SG safety relief, responded as expected or designed.
Both of the Pressurizer Power Operated Relief Valves (PORVs) cycled to -
mitigate the primary system pressure transient. Auxiliary feedwater initiated and injected into all SGs per design. All four SG PORVs and 20 safety relief valves cycled to the atmosphere to mitigate the secondary pressure transient due to closure of all i
MSIVs per design.
One safety relief (17A) was noted to 'close about 100 psig lower than d3 sign after the transient. This safety
relief was subsequently declared to be inoperable.
During the transient, an Unusual Event was declared.
Shortly after the SG PORVs and safety reliefs actuated, an object impacted the roof of the turbine building. This object was subsequently identified as a section of metal paneling from the facade attached
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to the upper region of the reactor containment building.
Several
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sections were dislodged and three sections became missiles due to-l the PORVs and safety relief valves lifting and releasing high pressure steam into the facade.
The unit was cooled down to Mode 4.
Cooldown was accomplished by the SG PORVs and sequentially the main steam dumps.
2.1.2 Steamline Isolation Valve Logic Operation Automatic steamline isolation valve closure on a containment high-high (Hi-2) pressure signal is generated by a two-out-of-three (2/3) trip logic.
Either engineered safety features actuation system (ESFAS) train A or B can initiate closure.
Manual isolation valve closure also can be initiated by the operators.
Additional signals that can close the isolation valves through the containment Hi-2 output driver card are low steam line pressure
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and high steam rate in any steam generator.
When the 2/3
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containment Hi-2 logic is satisfied, the driver card output j
transistor (Q7) will turn 'on' (= 1 volt collector to emitter)
energizing the master relay that initiates isolation valve i
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During normal unit operation, transistor Q7 is turned j
'off' which drops the power supply voltage (= 48 volts) across Q7.
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2.1.3 Troubleshooting
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Following the Unit 1 trip, the licensee identified that the MSIVs had inadvertently closed. The significant events recorder (SER)
j identified that the steamline isolation valves were not open and
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that in = 8 seconds a reactor trip occurred due to steam generator 1C low-low level. The licensee reviewed the SER printout and did not identify any signals that would have initiated MSIV closure.
Initial troubleshooting identified that Train
'A' automatic isolation valve closure master relay (K504) was energized with about 11 volts across the relay coil. With no actuation signal present, this value should be about 0 volts.
Output driver card (A516) transistor Q7 was biased 'off', however, the collector to emitter voltage was about 37 volts.
The licensee removed the driver card for bench testing.
Normal driver card operating conditions were established and a digital voltmeter was connected to monitor transistor Q7 output voltage. With transistor Q7 biased 'off', the voltage across transistor Q7 fluctuated between 25 and 31 volts. This indicated that transistor Q7 had excessive leakage current when biased 'off' and that this was the root cause for the inadvertent MSIV closure.
The licensee also checked the 2/3 logic universal input card (A315).
Random noise spikes (pulse width al p-second) were noted at the card's output.
Discussions with other utilities identified that similar random spikes had been observed in their cards. The licensee replaced the card as a precautionary measure.
The automatic self-test system uses about a 1 millisecond test pulse. The self-tester checks logic continuity without energizing the master relay. Since the self-test pulse is 1000 times wider than the random noise spikes, the noise spikes were not a precursor to the MSIV closure event.
The licensee performed surveillance procedure IBw0S 3.1.1-20,
" Unit 1 Train A Solid State Protection System Bi-Monthly Surveillance (Staggered)," and the new cards successfully passed the test.
In addition, the licensee indicated they were going to remove transistor Q7 from the driver card for further testing in the near future. The inspectors concluded the licensee had adequately addressed the root cause for this event.
2.1.4 Operations Response The operators and plant staff quickly responded to the event and ensured the plant was in safe shutdown conditions. Appropriate notifications were made timely and correctly.
The plant staff also inspected various systems and plant locations to ensure that vital equipment were not affected.
2.2 Unit 1 Heater Drain Tank (HDT) Rupture Disc Failure On August 19, 1994, while at 75 percent reactor power and ramping up following a reactor start, the Unit 1 HDT rupture disc failed.
Subsequently, operators shut down the unit to Mode 3 to inspect
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for damage and conduct repairs. On August 20, 1994, the unit was restarted.
In addition to the replacement of the blown rupture disc, the licensee inspected associated piping and discovered a crack in the condenser vent line which exhausts the HDT to the condenser in the event the rupture disc ruptures.
The mechanical maintenance department subsequently replaced the Unit 1 HDT rupture disc and completed a weld repair of the-condenser vent line.
The licensee conducted a root cause evaluation of the rupture disc failure.
During that evaluation, the licensee discovered that during the previous startup, the rupture disc became wetted and that historically this had caused premature failures.
The inspectors reviewed this finding and discovered that the system engineer was aware that the rupture disc had become wetted i
during the startup and had expressed some concern to the operations staff. However, since the rupture disc is in a moist environment during normal operations, the operations staff did not consider it a significant problem.
This is an unresolved item pending further NRC review of the licensee's actions and conditions around the rupture disc failure (50-456/94021-02).
2.3 Boric Acid Systera Walkdown The inspector performed a walkdown of the boric acid addition system during Mode 1 operation. Accessible portions of the system was inspected to verify proper alignment of valves, instrumentation, power supply breakers, material condition, and overall housekeeping.
In addition, the inspector reviewed licensee procedures and logs associated with the boric acid system.
The following deficiencies were noted:
Overall system cleanliness was poor.
Residual boron from
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prior batching evolutions had not been effectively controlled.
In addition, an e.xcessive amount of tools and other debris was observed in the boric acid skid and batch tank area.
The material condition of the system was adequate.
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various deficiencies included a boric acid tank access cover which leaked boron and had not been addressed, poor general area lighting in the boric acid tank room due to burnt out bulbs, and non-skid strips which were severely worn in this i
slippery environment.
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Batch tank sample results were not~always logged as required
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by Bw0P AB-5, and in one case a sample was drawn late.
These' deficiencies were identified by the' inspector to the licensee. The licensee stated that corrective action to prevent recurrence of similar deficiencies would be evaluated.
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No violations or deviations were identified.
3.0 Maintenance and Surveillance (IP 62703 and 61726)
Routinely, station maintenance and surveillance activities were observed
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and reviewed by the inspectors to ascertain that they were conducted in accordance with approved procedures, regulatory guides and industry codes or standards, and in conformance with technical specifications.
The following maintenance or surveillance activities were observed and
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i reviewed:
3.1 2HD005B, "2B Second Stage Reheater Drain Tank Outlet. Valve,"
Maintenance
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On August 16, 1994, the electrical maintenance department participated in a shift briefing to troubleshoot 2HD005B, the normal outlet from the 28 second stage reheater' drain. tank to the 27B high pressure heater.
This valve had failed closed earlier and an action request had been' generated.
The electricians performing the work came to the control room and
outlined the actions they planned to take. The unit supervisor-understood that the electricians intended to place a jumper across contacts 9 and 10 of relay LS-HD123X. This relay energizes when a high-high water level condition (Hi-2) level is present in the 27B heater and causes HD005B to close, as well as isolating extraction steam (ES) to the 27A and 27B heaters. The actuation of this relay also generates a 27B heater Hi-2 level alarm in the control room. Jumpering across contacts 9 and 10 of the relay would only cause the 2HD005B to stroke and avoid the other undesired consequences as described above.
During troubleshooting, an alarm was received in the control room indicating a Hi-2 level in the 278 heater.
Extraction steam to the 27A and 27B heaters isolated.
Subsequently, the operators were informed that the electrician had inadvertently actuated relay LS-HD123X and generated a false Hi-2 level signal in the 27B heater.
Isolation of ES to the 27A and 278 heaters resulted in a decrease in steam generator feedwater inlet temperature and a small power excursion above 100 percent. The inspectors reviewed the licensee's data and determined that the maximum average nuclear
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power during the transient was 101.28 percent and that no regulatory limits were exceeded.
Immediately, the unit operator directed the Hi-2 level signal in the 278 heater reset.
Following com71etion of this action, ES was restarted to the 27A and 27B heaters, and plant conditions returned to normal.
The inspectors followed up on this event and determined that although a troubleshooting briefing was held, the scope of actions performed exceeded those discussed.
This communication breakdown directly led to the unanticipated power excursion.
This item is closed.
Fuel Shipments to Westinghouse During shipment and transfer of new fuel from the site to Westinghouse, the inspector observed numerous examples of non-compliance with station cleanliness procedures.
On August 10, 1994, the inspector observed the transfer of new fuel from the new fuel vaults to Westinghouse containers for shipment back to Westinghouse for modifications. As part of this observation, the inspector noted several cleanliness procedural violations associated with the BwFP FH-31, " Fuel Handling Cleanliness Zones and Requirements":
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BwFP FH-31 required that personnel accountability be
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accomplished by logging each individual in and out of the control point using BwFP FH-31T1.
However, the inspector observed that personnel used the incorrect accountability form and failed to log out when leaving the area for extended or short periods of time.
BwFP FH-31 required that the entrance to a cleanliness zone
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II area include the applicabic procedure.
However, the inspector observed that the required procedure was not present at the entrance as required.
BwFP FH-31 required that a cleanliness zone II area be
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posted with a large, conspicuously placed sign having general instructions for entry.
However, the inspector observed that the sign posted did not reference the correct procedure with general instructions for entry as required.
In addition, BwFP FH-31 contradicted BwAP 1100-18, " Station Housekeeping / Material Condition Program," concerning cleanliness zone designations and cleanliness zone security requirements.
The inspector discussed the discrepancies with the licensee who acknowledged them and proposed corrective actions. At the end of the inspection period, the inspector observed additional fuel moves with no discrepancies noted.
However, the discrepancies as
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described above are an example of a violation (50-456/99021-Ol(DRP); 50-457/94021-01(DRP)).
One violation was identified.
3.3 Overtime Guidelines for Station Personnel The fiRC received a concern that mechaHcal maintenance personnel were exceeding guidelines for overtime.
L Jaining unit personnel are monitored by a computer program for weekly requirements while daily requirements are monitored by their supervisors. The payroll records were reviewed for the period in question and no deviations from the guidelines were observed. Supervisors, on the other hand, are not payed for overtime and usually do not record it on the payroll records. They are responsible for monitoring their own overtime. Since there were no accurate payroll records for supervisors, the guard house access records were reviewed for the period in question and no deviations from the guidelines were observed. This issue is closed.
4.0 Plant Support The following plant support activities were observed or reviewed to evaluate the involvement of support organizations in assuring safe and effective plant operation:
4.1 Radiological Protection 4.1.1 On August 30, 1994, two electricians began a routine fire protection surveillance in a non-radiological protected area (RPA) portion of the protected area.
Following completion of their duties, the electricians exited the work site by a different route during which they crossed into the RPA. Although clearly and distinctly posted as an area which required a Radiation Work Permit to enter, both workers failed to adhere to these requirements.
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Upon exiting the RPA into the turbine building, an alert radiation protection technician noted that the workers were not wearing electronic dosimetry, as required. When directly questioned, the workers admitted their mistake.
Braidwood Radiation Procedure, BwRP 5000-7, " Unescorted Access To and Conduct In Radiologically Posted Areas,"
required that personnel entering the RPA read and understand all radiological signs which appear at the access control point.
In addition, BwRP 5000-7 required that if an individual desires unescorted access into the RPA, then that person shall ensure that he or she has been issued a routine thermoluminescent detector (TLD) and at least one secondary dosimeter.
The failure of the two electricians to read and understand
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the postings at the RPA entrance and obtain required secondary dosimetry is an example of a violation (50-456/94021-01(DRP); 50-457/94021-01(DRP)).
The individuals involved were counseled and reviews indicated the event to be an isolated occurrence.
4.1.2 During the inspection pericd, four incidents involving discovery of contaminated material outside the RPA occurred.
On August 30, 1994, station labor personnel became contaminated while working in their storage cage outside the RPA.
Items inside the cage were found to be contaminated with both fixed and smearable contamination. The items included buckets which were used by personnel for sitting and a red hose used to perform maintenance on a steam cleaner.
In addition, followup surveys of the areas in which the affected personnel were present uncovered two chairs which contained smearable and fixed contamination.
On August 26, 1994, the licensee discovered a green 55 gallon drum with magenta paint near the bottom located ositside the plant, but within the protected area.
A complete survey of the barrel was performed. That survey identified 2000 dpm/100 cm3 fixed contamination on the bottom of the barrel.
Subsequently, the licensee transported the barrel back to the RPA.
On September 1, 1994, the licensee discovered a scaffolding knuckle painted magenta in the scaffolding being assembled in the turbine building. A survey of the knuckle revealed 1000 dpm/100 cm> fixed contamination.
Subsequently, the licensee relocated the knuckle back into the RPA.
On August 18, 1994, the licensee discovered a penetration eddy current cover plate with 10,000 dpm/100 cme smearable contamination on one bolt hole opening and 18,000 dpm/100 cme smearable contamination on another bolt hole opening located in a warehouse outside the RPA, but within the protected area.
Subsequently, the licensee relocated the plate back into the RPA.
Uncontrolled radioactive material outside the RPA is a recurring problem and is the subject of an NRC inspection report and inspection followup item (IFI 50-456/94009-01; 50-457/94009-01).
Braidwood Radiation Procedure, BwAP 575-5, " Release of Material From a Radiologically Posted Area" required that
" solid material shall not be given an unconditional release (from the Radiation Protection Area) until the material has been decontaminated and determined to be free of detectable radioactive material". The items described above were four.d
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e outside the RPA.
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This is an example of a violation (50-45G/94021-01(DRP); 50-
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One violation with two examples was identified.
J 5.0 Licensee Action on Previously Identified Items (IP 92701. IP 92702)
Unresolved Items (Closed) 50-456/94020-Ol(DRP): 50-457/94020-01(DRP): While securing the 2C condensate / condensate booster pump, the unit nuclear station operator (NS0) mistakenly closed the 2C feedwater pump discharge valve 2FW002C.
Details concerning this event are contained in inspection report 50-456/94020(DRP); 50-457/94020(DRP). The inspectors completed their review of this event and determined that the NS0s involved with the evolution intended to accomplish a component manipulation outside the governing procedure without directly informing supervision and obtaining guidance as required by BwAP 100-20, " Procedure Use and Adherence."
This is an example of a violation (50-456/94021-01(DRP); 50-457/94021-Ol(DRP)).
Prior to the end of this inspection, the licensee's corrective actions were implemented and appeared to be effective in
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ensuring that operators are aware of the requirements of BwAP.100-20.
One violation was identified.
6.0 Licensee Event Report (LER) Review (IP 92700)
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LERs were reviewed and closed based on the following criteria:
Reportability requirements were met.
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Immediate corrective actions were accomplished.
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Corrective actions to prevent recurrence has been or'will be
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initiated per technical specifications.
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(Closed) 457/94005:
Unit 2 Reactor Trip Due to Failed Feed Regulating Valve (FWRV.). A description of this event, as well as the licensee's immediate corrective actions appears in Inspection Report 50-456/94020(DRP); 50-457/94020(DRP).
Subsequent to those actions, the licensee sent parts from the 2FW510 and 2FW540 positioners to the chemical division of Commonwealth Edison Company's System Materials Analysis Department (SMAD) for further analysis.
SMAD confirmed that
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the cause of the 2FW510 positioner failure was due to a failure in the positioner 0-ring which caused excessive friction between the 0-ring and
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the valve positioner cylinder.
In addition, the licensee monitored feedwater valve positioner
temperatures shortly following the trip to determine if a temperature induced 0-ring degradation mechanism existed.
The results were as follows:
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1FW510 130af 2FW510 166af 1FW520 134aF 2FW520 121aF IFW530 151aF 2FW530 108aF 1FW540 136af 2FW540 140=F The licensee also noted that only the 2FW510 and 2FW540 valves had removable insulation blankets installed on the valve yoke.
This configuration tended to contain and channel heat coming off the valve.
The licensee removed this insulation from both the 2FW510 and 2FW540 valves prior to the plant restart.
The inspectors reviewed the licensee's short term and long term corrective actions for this event and have no further concerns. This j
item is closed.
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(Closed) 456/94012:
Inadvertent Main Steam Line Isolation at Power Due to Equipment Failure.
This event, as well as the licensee's corrective I
actions, are discussed in paragraph 2.1.
The inspectors had no l
additional concerns.
This item is closed.
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No violations or deviatiols were identified.
7.0 Report Review
During the inspection period, the inspector reviewed the licensee's (
Monthly Performance Report for May, July, and August 1994.
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inspector confirmed that the information provided met the requirements of Technical Specification 6.9.1.8 and Regulatory Guide 1.16.
No violations or deviations were identified.
8.0 Definitions l
Unresolved items j
Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, violations, or deviations. An unresolved item disclosed during the inspection is discussed in paragraph 2.2.
9.0 Persons Contacted K. Kaup, Vice President
- A. Haeger, Executive Assistant K. L. Kofron, Station Manager R. Stols, Support Services Director K. Bartes, Regulatory Assurance Supervisor R. Kerr, Engineering and Construction Manager
- 0. E. Cooper, Operations Manager (acting station manager)
- G. E. Groth, Maintenance Superintendent R. Byers, Work Control Superintendent
- D. Miller, Technical Services Superintendent
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A. D' Antonio, Quality Verification Superintendent D. Skoza, Engineering Supervisor S. Roth, Security Supervisor
- E. Roche, Health Physics Supervisor
- F. Lesage, Site Quality Verification Supervisor
- M. Browne, Procedures Group Supervisor
- J. Lewand, Regulatory Assurance
- T.
Forrest, Master Electrician
- T. Tulon, Nuclear Operating Department
- Denotes those attending the exit interview conducted on September 16, 1994.
The inspectors also interviewed other licensee employees.
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