IR 05000456/1999007

Insp Repts 50-456/99-07 & 50-457/99-07 on 990414-0524.No Violations Noted.Major Areas Inspected:Operations, Maintenance,Engineering & Plant Support

ML20196D477
Person / Time
Site:	Braidwood
Issue date:	06/18/1999
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20196D464	List: IR 05000456/1999007 ML20196D459
References
50-456-99-07, 50-456-99-7, 50-457-99-07, 50-457-99-7, NUDOCS 9906240286
Download: ML20196D477 (22)

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U.S. NUCLEAR REGULATORY COMMISSION REGIONlil Docket Nos: 50-456, 50-457 License Nos: NPF-72, NPF-77 '

Report No: 50-456/99007(DRP); 50-457/99007(DRP)

Licensee: Commonwealth Edison Company Facility: Braidwood Nuclear Plant, Units 1 and 2 Location: RR #1, Box 84 Braceville,IL 60407 Dates: April 14 through May 24,1999 Inspectors: C. Phillips, Senior Resident inspector J. Adams, Resident inspector D. Pelton, Resident inspector R. Mendez, Engineering Specialist K. Green-Bates, Engineering Specialist J. Roman, Illinois Department of Nuclear Safety Approved by: Michael J. Jordan, Chief Reactor Projects Branch 3 Division of Reactor Projects l

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EXECUTIVE SUMMARY Braidwood Nuclear Plant, Units 1 and 2 NRC Inspection Report 50-456/99007(DRP); 50-457/99007(DRP)

This inspection included aspects of licensee operations, maintenance, engineering, and plant support. The report covers a 6-week period of resident inspection from April 14 through May 24,199 Operations

The inspectors observed during a Unit 2 reactor startup, at the beginning of the inspection period, reactor operators did not consistently adhere to the operations department standards for control room formality, and operations management was not '

observed correcting this behavior. However, there were seven subsequent Unit 2 startup and shutdown evolutions during the period. During these evolutions the 1

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inspectors observed control ioom operators consistently adhering to procedures, using good three way communications, and demonstrating a good questioning attitud Operations management personnel were observed frequently challenging licensee personnel on the reasons for expected alarms and taking actions to minimize distractions in the control room. This more recent performance was an improvement I and was more consistent with previous operations department personnel performanc l

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In addition, the inspectors concluded that operators responded well to two Unit 2 reactor trips during the period. (Section O4.1)  !

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After a gas pocket was identified in Unit 1 ECCS piping the licensee made a sufficient l case and proposed acceptable compensatory actions to warrant the granting of a Notice of Enforcement Discretion on the Limiting Condition for Operation 3.0.3 action statement time requirements and an extension of 14 days. However, considerable NRC staff interaction was necessary to address this issue. The licensee exited the Limiting {

Condition for_ Operation for Technical Specification 3.0.3 on May 20. (Section 07.1) ;

l Maintenance

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The inspectors observed the performance of eleven surveillance tests. The inspectors concluded that the surveillance tests adequately tested the system, the operators followed the procedures, and that the procedures included the required testing discussed in the Technical Specifications. (Section M1.1)

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The inspectors observed all or portions of seven maintenance activities and concluded that activities were performed in accordance with the applicable procedures, that the procedures provided the requisite information necessary to perform the work, that maintenance personnel demonstrated good general work practices, and that maintenance personnel were knowledgeable of the associated Limiting Condition for Operation and high-risk work activity requirements. The entry into and exit from Limiting Conditions for Operation were properly entered into operating log '

i (Section M1.2)

- The inspectors identified a surveillance procedure that did not test the Technical Specification surveillance requirement that was stated in the procedure which indicated i a misunderstanding of the actual surveillance requirements. The inspectors verified that

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the Technical Specification surveillance requirements were met by other surveillance tests within the required periodicity and that there was no violation of Technical Specification requirements. (Section M3.1)

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On May 19, operators observed spiking on nuclear instrumentation intermediate range

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Channel N36 that resulted in a Unit 2 trip on intermediate range high flux. The inspectors concluded that the instrument maintenance department promptly developed and implemented a comprehensive troubleshooting plan in accordance with the licensee's procedure. The inspectors concluded the results of the troubleshooting activities were documented with sufficient detail. (Section M4.1)

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The inspectors concluded that the licensee performed acceptable troubleshooting activities in attempting to determine the cause of multiple rod control system urgent failures. However, the licensee was unable to determine the root cause due in part to the intermittent nature of the problem and problems with diagnostic equipment that complicated the troubleshooting efforts. (Section M4.2)

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On May 16, the inspectors performed a closeout inspection of the Unit 2 containmen The inspectors concluded containment cleanliness was excellent and had improved when compared to previous containment closecuts inspections. The problems identified during the inspection were few in number, were promptly corrected, and had little if any safety consequence. (Section 7.1)

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The inspectors concluded that the licensee's review of the Industry Operating l Experience Program for the Westinghouse twice burned fuel assembly gap phenomena j was effective, based on the demonstrated implementation of corrective actions. The j issues reviewed by the inspectors appeared to be appropriately dispositioned in a conservative manner. (Section E2.1)

Plant Sucoort

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The inspectors concluded that the as-low-as-reasonably-achievable briefing for entry into the Unit 2 containment provided the necessary information to allow personnel to avoid unnecessary radiation exposure. The as-low-as-reasonably-achievable briefing was comprehensive, concise, and effectively used survey maps to convey information on area dose rates. Inspectors concluded that the radiation work permit was complete and contained the necessary information for personnel to safely access the Unit 2 containment building. (Section R1.1)

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The inspectors concluded that the hot work observed was performed in accordance with Braidwood administrative procedure for control of hot work. This was an improvement over performance during previous refueling outages where inspectors found multiple examples of unattended energized welding equipment. (Section F1.1)

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' Begerf Detailt Summary of Plant Status -

Unit i eritered and remained at or near full power until May 16 when gas pockets were identified in piping that effected both trains of emergency core cooling. The licensee entered Technical Specification 3.0.3 and began a unit shutdown. The licensee requested, and was granted, a notice of enforcement discretion. Unit 1 was reduced to about 20 percent power before the licensee was granted the enforcement discretion and returned the unit to full power on May 17. Unit 2 entered the period in coast down. Unit 2 tripped from full power following a main turbine trip due to an erroneously indication of a bus ground fault from a ground fault relay. Unit 2 was restarted and made critical on the evening of April 14. The Unit was shutdown again on April 15, before it was synchronized to the grid, due to problems with the rod control system. Unit 2 was retumed to power again on April 16. The unit was then shutdown for refueling outage A2R07 on April 24. The Unit was made critical following the refueling outage on May 19, but subsequently tripped from about 3 percent power due to spiking of intermediate range nuclear instrument, N36. The Unit was retumed to criticality on May 20 and reached full power on May 2 . Operations 04 Operator Knowledge and Performance 04.1 Ooerator Performance Durina Several Unit 2 Events and Evolutions

] Insoection Scooe (71707)

The inspectors made observations of operator performance during portions of several Unit 2 evolutions and events and interviewed the cognizant operating and engineering personnel. The inspectors reviewed portions of the following: Unit 2 Braidwood General Procedure (2BwGP) 100-1, " Plant Heatup," Revision 13; 2BwGP 100-2, " Plant Startup,"

Revision 12; 2BwGP 100-3, " Power Ascension," Revision 15E ;2BwGP 100-4, " Power l

Descension," Revision 13; 2BwGP 100-5, " Plant Shutdown And Cooldown," Revision 19; and Braidwood Engineering Surveillance Procedum (BwVS) 500-6, " Low Power Physics Test Program With Dynamic Rod Worth Measurement," Revision 3E i Observations and Findinos On the morning of April 14, Unit 2 tripped from full power following a main turbine trip due to an erroneously indication of a bus ground fault from a ground fault relay. The inspectors responded to the control room and determined that the control room operators handled the transient well based on the verification of the completed emergency operating procedure actions and the observed stability of plant upon arrival in the control room. The cause of the trip was identified as a spurious actuation of the ground fault relay. The unit was restarted on the evening of April 14. During the Unit 2 reactor startup, the inspectors observed consistent adherence to startup procedure However, the inspectors noted that the control room was noisy during the startup, requiring the unit supervisor to repeat directions to crew members on several occasions, and that a significant number of people (greater than 15) were in the control room during the startup. The unit supervisor took no action to reduce the potential for distractio ,

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The inspectors did not identify any specific instance where the noise or the increased number of people resulted in a negative consequence that affected safe control room operation The inspectors also observed several examples of control room informality during startup activities such as; operations personnel leaning on the control panel guard bars, personnel leaning over control panels with cups of coffee in-hand, and informal three-way communications between the control room operators. Operations management did not correct the_ behavior until brought to their attention by the inspectors, even though it was obvious and occurred often. The inspectors observed similar behavior during the startup from the Unit 1 steam generator outage in the fall of 1998 (Inspection Report 50-456/457-98020 (DRP)). The inspectors were particularly concerned with the failure of operations department supervisory personnel to recognize and promptly correct the decline in formalit On th'e morning of April 15, licensee management decided to shutdown Unit 2 after experiencing problems with the rod control system. After repairs were made, Unit 2 was made critical again on the moming of April 1 On April 24, the inspectors observed contrcl room operators conduct a shutdown of Unit 2 for refueling outage A2RO7. The inspectors observed consistent adherence to shutdown procedures and the use of three-way communications by control room operators throughout the shutdown activities. The inspectors also noted that the unit supervisor maintained a " big picture" understanding of control room activities during a very busy time (e.g., changing plant conditions, changing operational modes, and conduct of various system testing). The inspectors noted that a nuclear station operator demonstrated a good questioning attitude when he pointed out that proposed system engineering testing of component cooling water valves was incompatible with the exist lng plant conditions of residual heat removal system primary plant cooldow Operations management delay the component cooling water testing. The shift manager demonstrated a good questioning attitude throughout shutdown activities by challenging control room operators as to why certain alarms received were " expected." The control room operators understood the basis for " expected" alarms when challenged by the shift manage During the Unit 2 reactor startup from refueling outage A2R07 on May 19, the inspectors observed that control room operators closely adhered to the startup procedures and were cons lstently using three-way communications. Reactivity changes were closely monitored by a dedicated reactor operator and a dedicated senior reactor operator. The inspectors observed continuous communications and cooperation between the operators monitoring reactivity and nuclear engineers. Operations department senior management personnel ensured that access to the control room was limited. Although the control room was still crowded the noise level was low and did not present any distraction. The inspectors noted that a control room operator performing a surveillance demonstrated a good questioning attitude by identifying that the local instrument readout for 2PT120, Unit 2 charging header pressure transmitter, was reading lower than expected. The low readout of this pressure instrument would have resulted in a surveillance failure and entry into Technical Specification Limiting Condition For Operation 3.5.5. The licensee installed a pressure gauge locally at the transmitter and determined that the surveillance test results met the acceptance criteri r c-

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Before Unit 2 was synchronized to the grid, the unit tripped from about 3 percent power due to spiking in nuclear instrumentation intermediate range drawer N36 on the afternoon of May 19. The inspectors responded to the control room after the trip. The inspectors concluded that the control room operators handled the transient well based on the verification of completed emergency operating procedure actions and the observed stability of plant upon arrival in the control roo Following repairs to N36, the reactor was made critical again on the aftemoon of May 20. As the reactor approached three percent power, operators observed the return of spiking on intermediate range channel N36. The operators blocked the high flux trip and reactor power increased above 10 percent where the flux trip was no longer active The inspectors reviewed Technical Specification 3.3.1.F and determined that the bypassing of the high flux trip was allowed for the current plant condition During the reactor startup, the inspectors observed consistent strict adherence to procedures along with the consistent use of peer checks. The inspectors also observed clear and concise communications between nuclear station operators and others in the control room. The response to alarms were excellent. For example, after an unexpected pressure relief tank high pmssure alarm was received, the reactor operator stopped outward rod motion, announced the alarm as an unexpected alarm, referred to the alarm procedure, and requested assistance from another licensed operator in the determination of the caus Conclusions During a Unit 2 reactor startup, at the beginning of the inspection period, reactor operators did not consistency adhere to the operations department standards for control room formality, and operations management was not observed correcting this t shavio However, there were seven subsequent Unit 2 startup and shutdown evolutions dunng the period. During these evolutions the inspectors observed control room operators consistently adhering to procedures, using good three way communications, and demonstrating a good questioning attitude. Operations management person.1el were observed frequently challenging licensed personnel on the reasons for expected alarms and taking actions to minimize distractions in the control room. This more recent performance was an improvement and was more consistent with previous operations department personnel performance. In addition, the inspectors concluded that operators responded well to two Unit 2 reactor trips during the perio Quality Assurance in Operations 07.1 Reauest For Notice of Enforcement Discretion (NOED) From Technical Specification 3.0.3 For Unit 1 Insoection Scooe (71707)

The inspectors reviewed the licensee's oral and written request for a NOED concerning ;

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extension of the shutdown requiren'ent of Technical Specification Limiting Condition for Operation 3.0.3 for Unit t :

b. . Otqorvations and Findinas On May 13, the licensee performed steps of Braidwood Operations Surveillance Procedure 1BwOSR 3.5.2.2-2, " Unit One Emergency Core Cooling System (ECCS)

Venting and Valve Alignment Surveillance," Revision 0. This surveillance test was performed to satisfy Technical Specification Surveillance Requirement 3.5.2.3 and l .resulted in the identification of gas in the ECCS piping outside containment. As a result, l the susceptible ECCS discharge piping highpoints without vent valves were ultrasonically examined. This examination identified a gas pocket about seven feet long and 3/4 inch deep in the B train ECCS piping. The B train of ECCS was declared inoperable and Limiting Condition for Operations 3.5.2 was entered which required that the affected ECCS train to be restored within 7 day To remove the gas pocket, a design change was initiated to install a vent valve in the affected B train ECCS piping This design change was installed on May 15. During verification that the newly installed vent was successful in removing the gas pocket

susceptible piping outside containment were again ultrasonically examined. This examination revealed the newly installed vent was successful in removing the original gas pocket; however, a different gas pocket of about 8.5 cubic inches in volume was identified. This pocket was located in the discharge piping section of piping that was common to both trains of low pressure safety injection section of the ECCS syste Both trains of ECCS were declared inoperable, putting the system outside of Limiting Condition for Operation 3.5.2. As a result, Limiting Condition for Operation 3.0.3, requiring a plant shutdown within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> was entered at 8:43 a.m. on May 1 The licensee commenced a power reduction and requested enforcement discretion on the Limiting Condition for Operation 3.0.3 action statement time requirements and an extension of 14 days. The NRC granted the NOED at 2:55 p.m. on May 16. However, considerable NRC staff interaction was necessary to address this issue. These interactions included a discussion on the affects of the gas pocket on the fuel peak cladding temperature if the gas pocket would have gotten swept into the reactor coolant

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system, and the consequences of a gas pocket on the piping inside the containment.

I The licensee successfully addressed these issues. An additional discussion was held on the results of the Plant Operation Review Committee (PORC) review of this NOED which was not complete. The licensee subsequently restored Unit 1 to full power. As a compensatory action for the NOED the licensee vented and ultrasonically examined piping within the containment. Gas was released from four vents within the containment. The licensee did not quantify this amount of gas before it was vented. In addition, the licensee identified three additional gas pockets totaling about .7 cubic feet of ga The licensee installed additional vent valves in ECCS piping highpoints outside of containment and vented the associated piping. An operability evaluation was prepared for the remaining gas in ECCS piping inside containment. Based on the venting of the gas outside containment and the operability evaluation for the gas inside the containment piping, the licensee exited the Limiting Condition for Operation's for Technical Specification 3.5.2 and 3.0.3 on May 20 at 11:18 l The root cause of the source of the ECCS piping gas and the licensee's identification and corrective actions regarding the existence of the gas in the ECCS piping is considered an Unresolved ! tem (50 456/99007-01(DRP)).

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l l Conclusions After a gas pocket was identified in Unit 1 ECCS piping the licensee made a sufficient case and proposed acceptable compensatory actions to warrant the granting of a NOED on the Limiting Condition for Operation 3.0.3 action statement time requirements and an extension of 14 days. However, considerable NRC staffinteraction was necessary to address this issue. The licensee exited the Limiting Condition for Operation's for Technical Specification 3.0.3 on May 2 Miscellaneous Operations issues (92901)

08.1 (Closed) Licensee Event Report 50-457/99001-00: Engineered Safety Feature Actuation (P-14) Due To High Water Level in the 2C Steam Generator. The licensee identified that a partial Unit 2 feedwater isolation occurred on April 24. The Unit was already shutdown for refueling outage A2R07. The inspectors verified that the licensee reported the event within the required time frame. The licensee's root cause evaluation was thorough and the corrective actions were appropriate for the causes identified. The root causes were identified as a procedural inadequacy, which allowed a flow path to exist from the condensate storage tank to the 2C steam generator while it was depressurized, and an operator mind set which lead them to believe the problem was leaking feedwater isolation valves. This one failure constitutes a violation of minor significance and is not subject to formal enforcement actio .2 (Closed) Violation 50-456/457/97015-01: " Failure to Take Effective Actions to Ensure Configuration Control." In August 1989, the licensee identified that containment spray system eductor drain valve 2CS0128 was closed but not locked as required by the applicable station mechanical valve line-up procedure. The inspectors determined that the licensee had performed a position verification on valve 2CS0128 approximately one week prior to the discovery of the valve locking issue. Licensee personnel had verified the position of 2CS012B without removing and reinstalling its locking device as was required by station procedure. The inspectors also determined that improper positioning of plant components had been a recurring problem for which corrective actions taken had not been fully effective. The inspectors reviewed the corrective actions taken by the licensee in regard to this violation. The licensee performed " tailgate" briefings and formal classroom training with operations department personnel concerning component positioning and methods of position verification. The licensee performed an audit of locked components which included checks of installed locking devices; no discrepancies were discovered. Braidwood Administrative Procedure BwAP 330-11," Operations Locked Safety Related Valve Key Control", was rewritten for clarity and to amplify instructions conceming proper completion of required logs. The inspectors have noted no recent examples of improperly installed locking devises or locked components that were discovered to be improperly positioned. This item is closed.

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11. Maintenance M1 Conduct of Maintenance M1.1 Observation of Miscellaneous Surveillance Activities Insoection Scope (61726)

The inspectors observed all or portions of the following surveillance activities:

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2BwOSR 3.8.1.2-1, " Unit Two 2A Diesel Generator Operability Monthly and Semi-Annual Surveillance," Revision 0;

• Braidwood Engineering Surveillance Procedure 2BwVSR 3.8.1.14-1, " Unit 2 2A Diesel Generator 24 Hour Endurance Run 18 Month," Revision 0;

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2BwVSR 3.8.1.15-1, " Unit 2 2A Diesel Generator Hot Restart Test 18 Month,"

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2BwOSR 3.8.1.2-2, " Unit Two 28 Diesel Generator Operability Monthly and Semi-Annual Surveillance," Revision 0;

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2BwVSR 3.8.1.14-2, " Unit 2 2B Diesel Generator 24 Hour Endurance Run 18 Month," Revision 0;

• 2BwVSR 3.8.1.15-2, " Unit 2 28 Diesel Generator Hot Restart Test 18 Month,"

Revision OE1;

2BwOS ATWS-SA1, " Unit Two ATWS [ Anticipated Transient Without SCRAM)

Mitigation Semiannual Surveillance," Revision OE3;

2BwVSR TRM 2.7.a.1, " Unit Two Auxiliary Feedwater Diesel Prime Mover Performance Surveillance," Revision 1;

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2BwVSR 5.5.8.AF.2," Unit Two Diesel Driven Auxiliary Feedwater Pump ASME

[American Society of Mechanical Engineering] Quarterly Surveillance,"

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BwVSR 3.5.2.8, " Visual Surveillance of Containment Recirculation Sumps,"

Revision 0; and

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BwVSR 5.5.8.SI.4, " Safety injection System Check Valve Stroke Test,"

Revision Observations and Findinos Between April 14 and May 21,1999, the inspectors observed the performance of the above listed surveillance tests. For each surveillance test, the inspectors observed the establishment of initial conditions required for the surveillance test, the operation of equipment, the communications between the licensed operators in the control room and non-licensed operators in the auxiliary building, and the restoration of affected

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equipment. The inspectors determined that each of those activities were performed in accordance with the applicable procedure. The inspectors reviewed the data obtained durir g the surveillance tests and noted that it met the required acceptance cr;ieria specfied in the surveillance test procedures. The inspectors also reviewed the associated portions of the Updated Final Safety Analysis Report and the Technical Specifications and determined that the surveillance test procedures demonstrated the

) systems performed as designed.

I Conclusions The inspectors observed the performance of eleven surveillance tests. The inspectors concluded that the surveillance tests adequately tested the system, the operators ;

folicwed the procedures, and that the procedures included the required testing discussed in the Technical Specification M1.2 Maintenance Activity Observations Inspection Scope (62707)

The inspectors observed all or portions of the following maintenance activities:

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Disassembly, inspection, and overhaul of essential service water system valve 2SX0178 in accordance with work request (WR) 980081098 01;

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Coupling inspection and grease replacement on essential service water system pump 2SX01PB in accordance with WR 960022703-01;

Overhaul of essential service water system valve 2SX21588 in accordance with WR 98006.5024-01;

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Overhaul of essential service water systcm valve 2SX2157D in accordance with WR 980064861-01;

Instailation of a freene seal on line 2SX16AB-3"in accordance with WR 980064861-02;

• Disconnecting temporary power to 125 volt direct current engineered safety feature Bus 212 in accordance with SPP 99-019, Revision 0; and

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Clean and ir Wect the 2B centrifugal charging pump gear oil cooler in accordance o n WR 080049741-0 Observations and Findinas The inspectors attended the heightened-level-of-awareness meetings, reviewed the above work packages; reviewed high-risk work check sheets. if applicable; walked down the work areas with maintenance perconnel; questioned personnel concerning the scope of the work, including system stotus, and precautions for electrical safety; observed the establishment of required system conditions; observed the use of foreign material exclusion controls; reviewed applicable welding procedures and " hot work" permits; end observed the use of quality control" hold points" and had no concerns. The

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t inspectors also revie'wed the associated Limiting Condition for Operation, if applicable, and reviewed the control room operating logs for Limiting Condition for Operation entry ond exit tog entries. The inspectors noted no problem ,

l Conclusions The inspectors observed all or portions of seven maintenance activities and concluded that activities were performed in accordance with the applicable procedures, that the procedures provided the requisite information necessary to perform the work, that maintenance personnel demonstrated good general work practices, and that  !

maintenance personnel were knowledgeable of the associated Limiting Condition for i Operation and high-risk work activity requirements. The entry into and exit from Limiting Conditions for Cperation were properly entered into operating log M3 Maintenance Procedures and Documentation i

M3.1 Unit 1 Undervoltaae Simulated Start of 1 A Anxiliary Feedwater Pumo Surveillance Monthly inspection Scope (61726)

The inspectors reviewed Surveillance Procedure 18wOSR 3.3.2.3. "Undervoltage Simulated Statt of 1 A Auxiliary Feedwater Pump Monthly Surveillancef Revision 0 and

. Technical Specification Surveillance Requirement (SR) 3.3. Observations and Findinas Surveillance Procedure 18wOSR 3.3.2.3, Step A, stated that the surveillance test was to be perfarmed to meet Technical Soecification SR 3.3.2.3. The inspectors determined that the surveillance test did not meet the survei!!ance requirements of SR 3.3. However, the surveillance requirements of SR 3.3.2.3 were met by surveillance procedure IJnit 1 Braidwood Operating Surveillance Procedure (18wOSR) 3.3.5.1-1,

" Bus 141 Undervoltage Protection Monthly Surveillancel Revision 0. Although there was no violation, this indicated a misunderstanding of what the actual surveillance requirements were. The licensee entered the discrepancy into the corrective action program to change the procedure statement of applicability for 18wOSR 3.3.5.1-1 and to review which parts if any of 18wOSR 3.3.2.3 were still necessary or desire Conclusions The inspectors identified a surveillance procedure that did not test the Technical Specification surveillance requirement that was stated in the procedure which indicated a misunderstanding of the actual surveillance requirements. The inspectors verified that the Technical Specification surveillance requirements were met by other surveillance tests wdhin the required periodicity and that there was no violation of Technical Specification requirement ,

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M4 L Maintenance Staff Knowledge and Performance

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s M4.1 . Observation of Nuclear Instrumentation Intennediate Ranae Channel NQH Rgubleshootina

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, Insoection Scooe (62707I The inspectors attended a pre-job brief for the troubleshcoting of nuclear

' instrumentation intermediate range channel N36 and observed troubleshooting

activities. The inspectors also reviewed the following documents

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" WR 980098103-01," Troubleshooting of Intermediate Range Channel N36"; j

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~Braidwood Instrument Surveillance Requirement Procedure j (BwlSR) 3.3.1.11-204, " Calibration of Nuclear Instrumentation System

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Intermediate Range," Revision 3; and

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- Prompt Investigation Report for Problem Identification Form A1999-01692, l

" Reactor Trip Due to intermediate Range Detector 36 Spiking." Observations and Findinas On May 19, operators were conducting a startup of Unit 2 when they observed spiking on nuclear instrumentation intermedia +e range channel N36. Shortly therea'ter, the spiking resulted in a Unit 2 trip on intermediate range high flux. The inspectors attended a pre-job briefing for the troubleshooting of intermediate range channel N36. The inspectors noted that the pre-job brief was performed by the instrument maintenance supervisor and was attended by the instrument technicians assigned to perform the l

work. The work package was reviewed in detail as was portions of BwlSR 3,3.1.11-204 I referred to by the work package. The instrument maintenance job supervisor used a l check list and ensured each pre-job briefing requirement was met prior to concluding -1 the brie !

The inspectors reviewed WR 980098103-01 and determined that the package contained )

more detail than previously reviewed troubleshooting packages. The inspectors noted i that the troubleshooting package contained numerous references to BwlSR 3.3.1.11- '

204 for detailed direction and for applicable acceptance criteri ' The inspectors noted that instrument technicians observed all applicable elec'rical safety ;

precautions,' followed instruction of WR 980098103-01 and BwlSR 3.3.1.11-204, '

compared as-found conditions to the applicable acceptance criteria, documented the results, and discussed results with supervisors. Supervisors were observed closely

' following the troubleshooting activities. When initial troubleshooting activities failed to

. identify the cause of the spiking, the licensee involved site and system engineering as well as the vendor in the troubleshooting efforts. Repair efforts included replacing the drawer power supply and cleaning cable connections. The spikes subsided and the Unit 2 startup was continued. When Unit 2 was at about 3 percent reactor power, the spikes on N36 began again. The high fiux trip was blocked until reactor power could be increased above 10 percent. The inspectors reviewed Technical Specification 3.3. and determined that the blocking of the high flux trip on one channel was allowed for the

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time duration to allow power level to increase above the point where N36 no longer would cause a trip. Troubleshooting effods continu Qqn_qlusions On May 19, operators observed spiking on nuclear instrumentation intermediate range channel N36 that resulted in a Unit 2 trip on intermediate range high flux. The inspectors concluded that the instrument maintenance department promptly developed and implemented a comprehensive troubleshooting plan in accordance with the licensee's procedure. The inspectors concluded the results of tne troubleshooting activities were documented with sufficient detail.

M4.2 Unit 2 Uraent Rod Control Failure T_r.gubleshootina Activities Inspection Scoce The inspectors observed the troubleshooting activities by maintenance personnel of Unit 2 urgent rod control failures that occurred between April 14 and 16,199 Observations and Findinas On April 14,1999, at 4:30 a.m., the Unit 2 generator ground fault GlX relays caused the generator output breakers to trip which caused the reactor to trip. The licensee l identified the root cause of the problem quickly and re-started Unit On April 14 at 3:00 p.m.. the operators closed the reactor trip breakers and withdrew the shutdown rods. At 7:32 p.m., a rod control system urgent failure alarm was received i in the control room while withdrawing one of the control rod banks. The urgent alarm ,

and a logic error alarm occurred in rod control power cabinet 2AC. The licensec !

suspected failure of a movable phase and a movable firing card as the possible causes i of the alarms. Licensee personnel performed some simp'e troubleshooting and i replaced the suspected parts. Further troubleshooting activities identified no additional problems. The operators withdrew rods and made the reactor critical at 11:07 On April 15, at 3:13 a.m., another a rod control system urgent failure alarm was indicated in power cabinet 2AC. Maintenance personnel continued troubleshooting for several hours and replaced several components in the 2AC power cabinet but were unsuccessful in identifying a root caus At 8:05 a.m., control banks C and D became misaligned during troubleshooting and failed to meet the over lap limit of 113 steps as required by the Core Operating Limits Report. This resulted in entry into the action statement of Limiting Condition for Operation 3.1.6 for control bank sequence or overlap limits not being met. The ieason for the rod misalignment could not be explained. Licensee management believed the problem to actually be in the rod position system instead of an actual rod misalignmen The licensee conservatively temporarily halted troubleshooting efforts until the rod misalignment could be explaine At 1:00 p.m., it became evident that the repair activities to the rod control system would continue beyond the Technical Specification limits and a Unit 2 shutdown was mitiated with a manual trip of the reactor. The licensee developed a more comprehensive

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troubleshooting plan with clearsr documentation requirements. Troubleshooting activities continued after the unit shutdown. The licensee inspected and cleaned several components and performed a partial control rod surveillance with no problems or alarms identifie The licensee again commenced a reactor startup and reactor was critical at about 6:00 a.m. on April 16. At 8:23 a.m., a rod control system urgent failure alarm on power ,

cabinet 1 AC occurred. Trouoleshooting continued until about 8:30 a.m. April 17. The I rod control urgent failure alarm was cleared and problems did not recur after this tlm The licensee was unable to identify a single root cause. The material condition of test equipment such as extender cards and strip chart recorders complicated the troubleshooting efforts. At one point in the trouble shooting the pulse shaper circuit card

'was replaced twice before it was determined that the extender card had a damaged solder joint and that a high resistance between the card and the neutral bus caused by dirt was resulting in bad output indications. In addition, at one point a bare multi-channel recorder lead had an unexpected circuit interaction and actually caused an urgent failure alar Conclusions The inspectors concluded that the licensee performed acceptable troubleshooting activities in attempting to determine the cause of multiple rod control system urgent failuros. However, the licensee was unable to determine the root cause due in part to the intermittent nature of the problem and material condition problems with test equipment that complicated the troubleshooting effort M Quality Assurance in Maintenance Activities M7.1 Unit 2 Containment Closeout lnspection Scope (61726)

The inspectors performed a closeout inspection of the Unit 2 containment and reviewed 2BwOS TRM 2.5.b.1, " Unit 2 Containment Loose Debris Inspection," Revision 0. The inspectors performed these activities after the licensee informed the inspectors that they had completed their close out inspectio Observation and Findin.qs On May 16, the inspectors performed a closeout inspection of the Unit 2 containmen The inspectors observed very little loose debris and noted that the containment floor drains were free from debris and standing water. The inspectors identified a one square foot piece of plastic covering a floor drain near the reactor cavity that had been installed as a beta shield. The plastic was removed by the licensee immediately. The inspectors determined that this example had minor safety consequence based on the location of the plastic and its small surface area relative to the surface area of the containment recirculation sump screen The inspectors noted that the degraded protective coating (paint) on the containment walls, reactor containment fan cooler ducts, and safety injection accumulators identified earlier on an initial entry into the Unit 2 containment had been removed and the paint

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flakes were cleaned up. The inspectors determined that the remaining paint appeared to be in good conditio The inspectors observed that the containment recirculation sump primary and secondary screens were free of debris and the rnodification to close gaps in the containment sump screen plates had been completed. However, the inspectors identified four small areas l

where gaps greater tNn 3/8 inch existed due to improper installation of metal plates

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associated with the modification. The inspectors informed the licensee of the existence of these gaps. The licensee entered the problem into their corrective actions program, initiated an investigation into the cause, and properly installed the metal plates eliminating the excessive gaps in the containment recirculation sump screen l As part of their investigation, the licensee reviewed WR 970117403 (train A) and l 970117404 (train B) for the removal and re-installation of the sump screens, and l BwVSR Procedure 3.5.2.8 for the inspection of the recirculation sump and determined that the documents contained no instructions regarding the proper installation of the metal p'ates associated with the modification to eliminate the excessive gaps in the sump screens. The Code of Federal Regulations, Title 10, Part 50, Appendix B, Criteria V, " Instructions, Procedures, and Drawings," states, in part, that instructions, procedures, or drawings shall include appropriate quantitative or qualitative acceptance criteria for determining that important activities have been satisfactorily accomplishe !

Contrary to the above, WR 970117403 failed to include instructions and appropriate i quantitative or qualitative acceptance criteria for the proper ir'stallation of metal plates associated with a containment recirculation cump screen modification to eliminate excessive gaps. The inspectors considered the gaps to be of low safety consequence '

because of the small area and that there were two more internal screens inside the sump. However, tnis was the second time that inspectors identified a similar problem with the installation of the sump screen modification'during a containment closecut inspection. This failure constitutes a violation of minor significance and is not subject to formal enforcement actio Conclusion Ori May 16, the inspectors performed a closeout inspection of the Unit 2 containmen The inspectors concluded containment cleanliness was excellent and had improved when compared to previous containment closecuts inspections. The problems identified during the inspection were few in number, were promptly corrected, and had little if any safety consequenc M8 Miscellaneous Maintenance issues (92902)

M8.1 (Closed) Violation 50-458/457/97016-03fDR_PJ Failure to follow procedural requirements for the construction, inspection, and tracking of scaffolding. During the months of August and September 1997, the inspectors and the licensee identified numerous examples of the failure to follow procedural requirements regarding construction, inspection, and tracking of scaffolding in areas affecting the operation of both units and a violation was issued. In response, the licensee has shifted the responsibility for the coordination of scaffolding from the construction department to the mechanical maintenance department, assigned a scaffold coordinator, and developed a new process for the documentation, tracking, construction, inspection, and removal of scaffolds. The inspectors reviewed the licensee's corrective actions and observed

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numerous scaffolds in the plant and determined that the corrective actions taken by the licensee have been effective at preventing recurrence. This violation is close . Ennineerina E2 Engineering Support of Facilities and Equipment E Industry Operatina Exoerience Proaram Inapection Scope (37551. 40500)

- The inspectors reviewed the licensee's actions regarding the industry information concerning the difficulty in latching onto the top of Westinghouse twice burnt fuel assemblies.' j Observations and Findinas

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Several utilities had experienced difficulties in latching onto the top nozzle of Westinghouse twice bumt fuel assemblies Video examinations of the fuel assemblies l revealed 1/16 - 1/8-inch gaps between the holddown spring block assembly clamp and the top nozzle, which indicated a failure of the Inconel top nozzle holddown spring ,

screws. The inspectors observed that the station management properly screened and i

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addressed a' corporate problem identification form (PlF) issued to all applicable Commonwealth Edison plants on April 23,1999, that identified this issue with failed '

holddown spring screws. As a result of the problem identification form, a visual i inspection of all twice burnt fuel removed from the Braidwood Unit 2 core during A2R07 i and scheduled for re-use was performed. The inspectors found that while difficulties !

were experienced latching onto two of the Braidwood fuel assemblies removed from the core due to the gap phenomenon, Braidwood staff were well prepared and the core i unload was only slightly delaye Inspectors also observed that when discrepancies were identified within the Braidwood twice bumt fuel assemblies, the licensee made a conservative decicion not to reuse any :

twice burnt fuel removed during this cycle and reloaded fuel from the fuel pool that was known not to have this problem. The inspectors noted that the licensee stayed in close

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contact with the fuel vendor at all times and was sending a staff member to participate in the Westinghouse root cause evaluation. Subsequent meetings between the vendor, L NRC, and licensee to discuss the Westinghouse safety assessment for this issue ;

determined that there was no potential for loose parts, no impact on control rod i insertion, no impact on fuel assembly vibration, and seismic-loss of coolant accident response of the affected fuel assemblies remained within the boundaries of the current analyses. The issue appeared to only impact outage schedules for fuel handling and a guideline for future fuel handling was prepared by the vendor and issue Conclusions <

The inspectors concluded that the licensee's review of the Industry Operating

, Experience Program for the Westinghouse twice bumed fuel assembly gap phenomena

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was effective, based on the demonstrated implementation of corrective actions. The 16-

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issues reviewed by the inspectors appeared to be appropriately dispositioned in a conservative manne E8- Miscellaneous Engineering issues (92903)

. E LQlosed) Violation 50-456/457/97022-01: " Failure to Take Corrective Actions to

' Preclude Failures of Main Feedwater Check Valves." In 1989, the licensee identified that all four Unit 2 main feedwater check valves (2FWO79A, B, C, and D) had seized

open due to insufficient clearances between critical components in the valve dampening mechanisms. The inspectors determined that similar valves on Unit 1 had previously failed for similar reasons but that the licensee had not initiated a deviation report or taken corrective actions to preclude repetition of the check valve failures. This was contrary to the requirements of BwAP 1250-2, " Deviation Reporting." The inspectors reviewed the corrective actions taken by the licensee in regard to this. violation. The licensee updated the maintenance procedure for the main feedwater check valves to include improved work instructions and dimensional checks. The licensee reviewed a sample of work procedures (a total of ten) and determined that required acceptance criteria was properly documented. The inspectors reviewed the work packages for the refurbishment of Unit 2 main feedwater check valves performed during refueling outage A2RO7 and determined that the work instructions had been revised to require the measuremerit and documentation of critical clearances necessary to preclude recurrence of past seizing problems. This item is close E8.2 (Closed) Violation 50-456/457/98005-03: " Unauthorized Temporary Alteration of the Spent Fuel Pit Skimmer System." in March of 1998, the inspectors identified that the spent fuel pool had two skimmer suction strainers and that the strainers were attached to the side of the spent fuel pool using rope. The original design of the spent fuel pool skimmer strainers utilized tee-handled adjustment assemblies attached to the side of the spent fuel pool which allowed strainers to be positioned as necessary based on spent 1 fuel pool level. The inspectors determined that set screws used to hold the strainers in the desired position had become stripped with use and would no longer hold the strainer in position. The licensee disconnected the strainers from the tee-handle and tied the suction strainers to the side of the spent fuel pool using a rope to maintain the desired position. The inspectors determined that the use of the rope to position the strainer suctions constituted a temporary alteration in accordance with BwAP 2321-18,

" Temporary Alterations" and determined that the licensee had not applied the administrative controls, required by BwAP 2321-18, to this alteration. The licensee removed the spent fuel pool skimmer system from service and provided refresher training to engineering personnel on the requirements for temporary alterations. The

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licensee has subsequently replaced the original spent fuel pool skimmer suction strainer design with a floating skimmer vessel and new hoses. The inspectors reviewed these corrective actions and concluded that actions taken should preclude recurrence of the problem. This item is close E8.3 (Closed) Violation 50-456/457/98005-04 " Failure to Maintain Fuel Pool Design." In March of 1998, the inspectors identified that the spent fuel pool design would not have prevented an inadvertent draining below 423 feet, O inches as is required by Technical Specifications design features requirement 5.6.2. The inspectors determined that the

~ spent fuel pit skimmer system discharge piping extended into the spent fuel pool to an ,

elevation of 419 feet 6 inches and had no syphon break. While investigating the above issue, the licensee identified that a flexible hose that attached the spent fuel pool I-17 j

l skimmer suction strainer to the skimmer system h'ad deteriorated and was broken at an elevation of 420 feet. This too created a pathway for inadvertent drainage of the spent fuel pool below 423 feet,0 inches. The inspectors determined that although the design of the spent fuel pool was not in accordance with the Technical Specification, the design did meet the requirements discussed in Regulatory Guide 1.13, " Spent Fuel Storage Facility Design Basis" and 10 CFR 50, Appendix A, Criterion 61, " Fuel Storage and Handling and Radioactivity Control." The licensee submitted a license amendment request to revise the Technical Specifications design features requirement for spent fuel pool drainage to be consistent with the minimum spent fuel pool water level requirements of Regulatory Guide 1.13 and 10 CFR 50, Appendix A, Criterion 61. The amendment request received final NRC approval. This item is close IV. Plant Support

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i R1 Radiological Protection and Chemistry (RP&C) Controls l

R1.1 As-Low-As-Reasonably-Achievable (ALARA) Briefina For Containment Entry Inspection Scope (71750)

The inspectors attended an ALARA briefing for entry into the Unit 2 containment. The inspectors reviewed radiation Work Permit 996001, Observations and Findinos The inspectors attended a ALARA briefing conducted by radiation protection personne The inspectors noted that radiation protection personnel discussed the radiological conditions of each floor of the containment building. Included in this discussion were the location of very high radiation areas, high radiation areas, contaminated areas, and low dose areas. Radiation protection personnel also performed a detailed review of the radiation work permit. The inspectors reviewed the radiation work permit and determined that radiation protection personnel provided comprehensive presentation of the information contained in the radiation work permit. The inspectors noted that the radiation work permit contained the required informatio Conclusions The inspectors concluded that the ALARA briefing for entry into the Unit 2 containment provided the necessary information to allow personnel to avoid unnecessary radiation exposure. The ALARA briefing was comprehensive, concise, and effectively used survey maps to convey information on area dose rates. Inspectors concluded that the radiation work permit was complete and contained the necessary information for personnel to safely access the Unit 2 containment buildin [:

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F1 Control of Fire Protection Activities F1,1 Observation of Hot Work Activities Inspection Scoop (71750)

The inspectors observed several hot work activities that were in progress and several unattended welding machines. The !nspectors reviewed BwAP 1100-15, " Fire l Prevention When Welding, Cutting, Grinding, or Performing Open Flame Work (Hot l Work)," Revision 10E Observations and Findinas l

} On May 6 and 7, the inspectors observed several hot work activities that were in l

progress and observed the as-left condition of several welding machines at work sites with no work in progress. The inspectors noted that the requirements of BwAP 1100-15 were met at each of the work sites observed. This was considered an improvement over performance during previous refueling outages where inspectors found multiple examples of unattended energized welding equipmen Conclusions The inspectors concluded that the hot work observed was performed in accordance with Braidwood administrative procedure for control of hot work. This was an improvement over performance during previous refueling outages where inspectors found multiple examples of unattended energized welding equipmen V. Manaaement Meetinas X1 Exit Meeting Summary -

The inspectors presented the inspection results to members of licensee management at the l conclusion of the inspection on May 24,1999. The licensee acknowledged the findings presented. The inspectors asked the licensee whether any materials examined during the inspection should be considered proprietary. No proprietary information was identifie l

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PARTIAL LIST OF PERSONS CONTACTED Licenpaq l l T. Tulon, Site Vice President I

• K. Schwartz, Station Manager l

• R, Wegner, Operations Manager j i L. Guthrie, Maintenance Manager

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l l A. Haeger, Radiation Protection Manager  !

l R. Graham, Work Control Manager

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'T Simpkin, Regulatory Assurance Manager

• T. Luke, Engineering Manager

• C.'Herzog, Services Manager ,

• M. Riegle, Nuclear Oversight Manager I

• G. Baker, Security Administrator

• F. Lentine, Design Engineering Supervisor -  ;

l *M. Cassidy, Regulatory Assurance - NRC Coordinator

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,. *M. Jordan, Chief, Reactor Projects Branch 3 l

• C. Phillips, Senior Resident inspector J. Adams, Resident inspector

• D. Pelton, Resident inspector T. Tongue, Project Engineer l R. Mendez, Engineering Specialist l K. Green-Bates, Engineering Specialist

[pNS J, Roman

• Denotes those who attended the exit interview conducted on May 24,1999.

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INSPECTION PROCEDURES USED IP 37551: Engineering

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IP 40500: Effectiveness of Licensee Process to identify, Resolve, and Prevent Problems

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IP 61726: Surveillance Observations IP 62707: Ma'ntenance Observation IP 71707: Plant Operations IP 71750: Plant _ Support Activities

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IP 92700: Onsite Followup of Written Reports of Nonroutine Events at Power Reactor Facilities

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IP 92901: Followup - Plant Operations IP 92902: Followup - Plant Maintenance IP 92903: Followup - Engineering IP 93702: Event Response ITEMS OPENED, CLOSED, AND DISCUSSED Opened 50-456/457/99007-01 URI failure to meet Technical Specification Requirements Closed 457/99001-00 LER ESF actuation due to high water level in steam generator 456/457/97015-01 VIO failure to take actions to ensure configuration control 456/457/97016-03 VIO failure to follow procedures 456/457/97022-01 VIO failure to take corrective action 456/457/98005-03 VIO unauthorized temporary alteration of spent fuel pool 456/457/98005-04 VIO failure to maintain fuel pool design l

Discussed None

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LIST OF ACRONYMS USED ALARA As-Low-As-Reasonably-Achievable BwAP' Braidwood Administrative Procedure:

BwGP Braidwood General Procedure .

BwlSR ' Braidwood Instrument Surveillance Requirement Procedure BwOSR Braidwood Operations Surveillance Procedure

.BwVSR Braidwood Engineering Surveillance Requirement Procedure CFR Code of Federal Regulations ECCS Emergency Core Cooling System l&C - Instrument and Control -

NOED Notice of Enforcement Discretion NR Nuclear Regulatory Commission

.NRR Nuclear Reactor Regulations RP&C Radiological Protection & Chemistry SX - Essential Service Water VIO Violation j WR - Work Request I l I i

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