IR 05000352/2012007

IR 05000352-12-007 & 05000353-12-007, 8/27/2012 - 12/17/2012, Limerick Generating Station, Units 1 and 2, Component Design Bases Inspection

ML13015A400
Person / Time
Site:	Limerick
Issue date:	01/15/2013
From:	Paul Krohn Engineering Region 1 Branch 2
To:	Pacilio M Exelon Generation Co, Exelon Nuclear
References
IR-12-007
Download: ML13015A400 (38)

Text

't"ffi UNITED STATES NUCLEAR REGULATORY COMMISSION

REGION I

21OO RENAISSANCE BOULEVARD, SUITE 1OO KING OF PRUSSIA, PENNSYLVANIA 194042713 January 15, 2013 Mr. Michael Senior Vice President, Exelon Generation Company, LLC President and Chief Nuclear Officer, Exelon Nuclear 4300 Winfield Rd.

Warrenville, lL 60555

Dear Mr. Pacilio:

SUBJECT: LIMERICK GENERATING STATION - NRC COMPONENT DESIGN BASES I N S pECTt ON RE PO RT 05000352/20 1 2007 AN D 0500 0353 I 20 1 2007 On December 17,2412, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at the Limerick Generating Station, Units 1 and 2. The enclosed inspection report documents the inspection results, which were preliminarily discussed on September 28,2012, with Mr. T. Dougherty and other members of your staff. On December 17,2012the final result of the inspection were discussed with Wayne Lewis, Senior Manager Design Engineering and other members of your staff.

The inspection examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license.

ln conducting the inspection, the team examined the adequacy of selected components and operator actions to mitigate postulated transients, initiating events, and design basis accidents.

The inspection involved field walkdowns, examination of selected procedures, calculations and records, and interviews with station personnel.

This report documents two NRC-identified findings which were of very low safety significance (Green). The findings were determined to involve violations of NRC requirements. However, because of the very low safety significance of the violations and because they were entered into your correction action program, the NRC is treating them as non-cited violations (NCV)

consistent with Section 2.3.2.a of the NRC Enforcement Policy. lf you contest any of the NCVs in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555-0001, with copies to the Regional Administrator, Region l; the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555-0001; and the NRC Resident Inspector at the Limerick Generating Station. In addition, if you disagree with the cross-cutting aspect assigned to any finding in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the Regional Administrator, Region l; and the NRC Resident lnspector at Limerick Generating Station. ln accordance with Title ',l0 of the Code of Federal Regulations (10 CFR) 2.390 of the NRC's

"Rules of Practice," a copy of this letter, its enclosure, and your response (if any) will be available electronically for the public inspection in the NRC Public Docket Room or from the Publicly Available Records component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.qov/readino-rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/')

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/)/

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r-L'/,u 1,,-4-Paul G. Krohn, Chief Engineering Branch 2 Division of Reactor Safety DocketNo. 50-352, 50-353 License No. NPF-39, NPF-85

Enclosure:

Inspection Report 05000352/2Q12Q07 and 05000353/2012007 w/Attachment: Supplemental Information

REGION I==

50-352,50-353 NPF-39, NPF-85 05000352/201 2007 and 050003531201 2007 Exelon Generation Company, LLC (Exelon)

Limerick Generating Station, Units 1 and 2 Sanatoga, PA August 27 - December 17, 2012 K. Mangan, Senior Reactor lnspector, Division of Reactor Safety (DRS), Team Leader K. Young, Senior Reactor Inspector, DRS M. Orr, Reactor Inspector, DRS E. Burket, Reactor Inspector, DRS H. Campbell, NRC Mechanical Contractor J. Nicely, NRC Electrical Contractor J. Richmond, Senior Reactor lnspector, DRS (part time)

Paul G. Krohn, Chief Engineering Branch 2 Division of Reactor Safety Enclosure

SUMMARY OF FINDINGS

lR 0500035212012007, 0500035312012007; 812712012 - 1211712012; Exelon Generation

Company, LLC; Limerick Generating Station, Units 1 and 2; Component Design Bases Inspection.

The report covers the Component Design Bases Inspection conducted by a team of four NRC inspectors and two NRC contractors. Two findings of very low risk significance (Green) were identified; the findings were considered to be non-cited violations. The significance of most findings is indicated by their color (Green, White, Yellow, Red) using Inspection Manual Chapter (lMC) 0609, "significance Determination Process" (SDP). Findings for which the SDP does not apply may be Green or be assigned a severity level after NRC management review. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process," Revision 4, dated December 2006.

A.

NRC-ldentifiedandSelf-RevealinqFindinqs Gornerstone: Mitigating Systems

Green.

The team identified a non-cited violation of Title 10 of the Code of Federat Regutations (10 CFR) Part 50, Appendix B, Criterion lll, "Design Control," which states, in part, "design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program." The team determined that Exelon did not verify that adequate voltages would be available to safety-related equipment powered from the 4kV, 480vac, and 120Yac distribution systems during a design basis loss-of-coolant accident with offsite power available. Specifically, the team found that Exelon assumed a non-conservative offsite power voltage at the start of the event, used a non-conservative assumption for motor starting times, and did not have calculations that determined the minimum voltage level for the 480 Vac and 120Yac distribution level during post event electrical transients. Following questions from the team Exelon entered the issue into their corrective action program, revised existing calculations, performed new calculations, and completed evaluations to ensure that the minimum voltage level that would be reached during an event would be adequate at all three voltage levels. The team reviewed these calculations and evaluations and concluded the results of the work performed during the inspection were reasonable.

The team determined that the failure to verify adequate voltages at all voltage levels to safety-related equipment during a design basis loss-of-coolant accident was a performance deficiency. This issue was more than minor because it was similar to IMC 0612, Appendix E, "Examples of Minor lssues," Example 3.j, in that the design analysis deficiency resutted in a condition where the team had reasonable doubt of operability of the safety-related busses. In addition, it was associated with the design control attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team determined the finding was of very low safety significance (Green) because it was a design or qualificalion deficiency confirmed not to result in loss of operability or functionality. This finding had a cross-cutting aspect in the area of Human Performance, Resources, because Exelon did not

B.

provide complete, accurate and up-to-date design documentation to plant personnel and because these calculations had been recently revised. (lMC 0310, H.2(c))

(Section 1R21.2.1.1 5.1 )

Green.

The team identified a finding of very low safety significance (Green) involving a non-cited violation of Limerick Generating Station License Condition 2.C.(3), "Fire Protection," which states Exelon Generation Company shall implement and maintain in effect all provisions of the approved Fire Protection Program as described in the UFSAR.

Specifically, the team found that Exelon's multiple high impedance fault (MHIF)analysis, developed to verify that post-fire safe shutdown equipment would remain available, used non-conservative overcurrent trip setpoints for 480 volt overcurrent protection devices.

Specifically, the team found that molded case circuit breaker overcurrent protection did not protect against all possible faults currents that could be present on downstream equipment. "As a result, fault current greater than that assumed in the MHIF analysis could propagate past the circuit breaker and trip upstream equipment. Exelon entered the issue into their corrective action program and performed an analysis that showed credited equipment would be available. The team concluded the results of the work performed were reasonable.

The team determined that Exelon's selection of breaker trip values for use in the MHIF analysis was non-conservative and was a performance deficiency. Specifically, the post-fire safe shutdown MHIF analysis did not use worst case or maximum fault current to verify that fire induced fault currents that propagated past branch feeder circuit breakers would not cause the motor control center source breaker to overload and trip. This issue was more than minor because it was similar to IMC 0612, Appendix E, "Examples of Minor lssues," Example 3.j, in that the design analysis deficiency resulted in a condition where the team had reasonable doubt of operability of the MCC during a fire. In addition, this issue was associated with the Fire Protection attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team determined the finding was of very low safety significance (Green) because the finding affected the post-fire safe shutdown category and it had a low degradation rating. This finding did not have a cross-cutting aspect because the design requirements of the breakers had not changed from initial startup and therefore it does not reflect current licensee performance. (Section 1R21.2.1.15.2)

Licensee-ldentified Violations None lil

REPORT DETAILS

REACTOR SAFETY

Initiating Events, Mitigating Systems, Barrier Integrity

==1R21 Component Desiqn Bases Inspection (lP 71111.21)

==

.1 Inspection Sample Selection Process

The team selected risk significant components for review using information contained in the Limerick Generating Station (LGS) Probabilistic Risk Assessment (PRA) and the U.S. Nuclear Regulatory Commission's (NRC) Standardized Plant Analysis Risk (SPAR)model. Additionally, the Limerick Generating Station Units 1 and 2 Significance Determination Process (SDP) Phase 2 Notebook was referenced in the selection of potential components for review. ln general, the selection process focused on components that had a Risk Achievement Worth (RAW) factor greater than 1.3 or a Risk Reduction Worth (RRW) factor greater than 1.005. The team also selected components based on previously identified industry operating experience issues and component contribution to large early release frequency (LERF) was considered. The components selected were located within both safety-related and non-safety related systems, and included a variety of components such as pumps, breakers, heat exchangers, electrical buses, transformers, and valves.

The team initially compiled a list of components based on the risk factors previously mentioned. Additionally, the team reviewed the previous component design bases inspection reports and excluded those components previously inspected. The team then performed a margin assessment to narrow the focus of the inspection to 17 components and 5 operating experience (OE) samples. One component (main steam isolation valve)was selected because it was a containment-related structure, system, and component (SSC) and would be considered for LERF implications. The team's evaluation of possible low design margin included consideration of original design issues, margin reductions due to modifications, or margin reductions identified as a result of material condition/equipment reliability issues. The assessment also included items such as failed performance test results, corrective action history, repeated maintenance, maintenance rule (a)1 status, operability reviews for degraded conditions, NRC resident inspector insights, system health reports, and industry operating experience. Finally, consideration was also given to the uniqueness and complexity of the design and the available defense-in-depth margins.

The inspection performed by the team was conducted as outlined in NRC Inspection Procedure (lP) 71111.21. This inspection effort included walkdowns of selected components, interviews with operators, system engineers and design engineers, and reviews of associated design documents and calculations to assess the adequacy of the components to meet design basis, licensing basis, and risk-informed beyond design basis requirements. A summary of the reviews performed for each component, operating experience sample, and the specific inspection findings identified are discussed in the subsequent sections of this report. Documents reviewed for this inspection are listed in the Attachment.

.2.1.1 Unit 2. Division 1. 125 Vdc Batterv Charqer (2A1D103)

a.

lnspection Scope The team inspected the design, testing, and operation of the Unit 2, Division 1, 125 Vdc battery charger (2A1D103) to determine if it could perform its design basis function of providing direct current

(dc) power to connected loads during normal, transient, and postulated accident conditions. The team reviewed design calculations, drawings, and vendor specifications, and load profile studies to evaluate the battery charger capability.

The team reviewed maintenance and test procedures to determine whether they were adequate to ensure reliable operation and that they were performed in accordance with licensing basis requirements, industry standards, and vendor recommendations. The team compared as-found and as-left inspection and test results to established acceptance criteria to verify the charger's capability conformed to design basis requirements. The team interviewed system and design engineers and walked down the battery charger to independently assess the material condition, and to determine if the system alignment and operating environment were consistent with design assumptions.

Finally, the team reviewed corrective action documents and system health reports to determine if there were any adverse trends associated with the charger, and to assess Exelon's capability to identify, evaluate, and correct problems.

b.

Findinos No findings were identified.

.2.1.2 Unit 1 and 2 Reactor Protection Svstem Trip Svstem Relavs (C71A-K14 A throuqh H)

a.

lnspection Scope The team inspected the design, testing, and operation of the Reactor Protection System (RPS) trip relays (C71A-K14A through C71-K14H) to determine if they could perform their design basis function of initiating the reactor scram trip logic upon a valid reactor trip signal. The team reviewed technical specifications, vendor specifications, and design bases documents (DBD) to determine the performance requirements. Load studies were reviewed by the team to evaluate the RPS trip relay capability. The team reviewed maintenance and test procedures to determine whether they were adequate to ensure reliable operation and they were performed in accordance with licensing basis requirements, industry standards, and vendor recommendations. The team compared as-found and as-left inspection and test results to established acceptance criteria to verify the RPS trip relays capability conformed to design basis requirements. The team interviewed system and design engineers and walked down accessible portions of the RPS system to independently assess the material condition of the system, and to determine if the system alignment and operating environment were consistent with design assumptions. Finally, the team reviewed corrective action documents and system health reports to determine if there were any adverse trends associated with the RPS trip system relays, and to assess Exelon's capability to identify, evaluate, and correct problems.

b.

Findinss No findings were identified.

.2.1.3 Unit 1. Back-up Feedwater Uninterruptible Power Supplv (E/S-XX-121)

a.

lnspection Scope The team inspected the design, testing, and operation of the Unit 1 back-up feedwater Uninterruptible Power Supply (UPS) (E/S-XX-121) to determine if it could supply redundant power to the reactor feedwater pump turbine system control panels ( 1A-C1 49, 1B-C149, and 1C-C149) during normal, transient, and postulated accident conditions credited in the LGS PRA model. The team reviewed design calculations, drawings, vendor specifications, and load profile studies to evaluate the back-up feedwater UPS capability. The team reviewed maintenance and test procedures to determine whether they were adequate to ensure reliable operation and they were performed in accordance with licensing basis requirements, industry standards, and vendor recommendations.

The team compared as-found and as-left inspection and test results to established acceptance criteria to verify the back-up feedwater UPS capability conformed to design basis requirements. The team interviewed system and design engineers and walked down the accessible portions of the back-up feedwater UPS to independently assess the material condition, and to determine if the system alignment and operating environment were consistent with design assumptions. Finally, the team reviewed corrective action documents and system health reports to determine if there were any adverse trends associated with the back-up feedwater UPS, and to assess Exelon's capability to identify, evaluate, and correct problems.

b.

Findinqs No findings were identified.

.2.1.4 Unit 1 Hiqh Pressure Coolant lniection Pump (10P204)

a. Inspection Scope

The team inspected the Unit t high pressure coolant injection (HPCI) system pump to determine if it was capable of meeting its design basis function of providing high pressure cooling water to the reactor vessel under transient and accident conditions.

The team evaluated the ability of the HPCI pump to deliver the design and licensing bases flow rate at required pressure. The net positive suction head (NPSH) calculation for the HPCI pump was reviewed for maximum flow rates from both the condensate storage tank (CST) and suppression pool to determine if adequate NPSH was available at minimum water levels and atmospheric pressures. Additionally, the team reviewed a calculation to determine if minimum water level in the CST would prevent the formation of a vortex. The team reviewed full flow testing and in-service test results to determine if the pump performance bounded the flow requirements in the safety analysis and to determine if Exelon had adequately evaluated the potentialfor pump degradation. The team performed a walkdown of the pump and associated support features and interviewed system and design engineers to assess the material condition of the pump.

Finally, the team reviewed issue reports and system health reports to determine the overall health of the system, and to assess Exelon's capability to identify, evaluate, and correct problems.

b. Findinos No findings were identified.

.2.1.5 Unit 1 Hiqh Pressure Coolant Iniection Turbine (10521 1)

a. Inspection Scope

The team inspected the Unit 1 HPCI system turbine to evaluate if it was capable of meeting its design basis requirement of providing sufficient motive force to enable the HPCI pump to inject high pressure cooling water into the reactor vessel under transient and accident conditions. The team reviewed the HPCI room heat-up analysis to determine the temperature response of the HPCI room to ensure proper environmental qualification of the HPCI system components. The team reviewed operational and alarm response procedures to determine whether the turbine was being operated in accordance with vendor recommendations. The team reviewed surveillance and in-service test results to verify acceptance criteria were met and acceptance limits were adequate to ensure that any potential degradation of the turbine would not result in the system becoming inoperable. The team performed a walkdown of the turbine and associated support features and interviewed system and design engineers to assess the material condition of the turbine. Finally, the team reviewed issue reports and system health reports to determine the overall health of the system and to determine if issues entered into the corrective action program were appropriately addressed.

b.

Findinqs No findings were identified.

.2.1.6 2H Automatic Depressurization Svstem Valve (PSV-2F013H)

a. lnsoection Scope The team inspected the automatic depressurization system/safety relief valve (ADS/SRV) 2H to determine if it was capable of meeting its design basis function. The team reviewed applicable portions of the Updated Final Safety Analysis Report (UFSAR), Technical Specifications (TS), and the TS bases to identify the design basis requirements for this combination ADS/SRV pilot-operated relief valve. The team reviewed the vendor manual to identify design specifications for the relief valve, associated solenoid valve, and pneumatic actuator. The team also reviewed surveillance procedures, vendor testing results, and the most recently completed ADS logic system functional surveillance test results to determine whether the valve was capable of depressurizing the reactor vessel during design basis accident conditions as assumed in the accident analysis and whether test result acceptance criteria enveloped design basis limits. The team also reviewed the vendor manual to determine the recommended inspection and maintenance activities and compared those recommendations to Exelon's rebuild and repair procedures, and scheduling database.

Finally, the team reviewed issue reports and system health reports to determine the overall health of the system and to determine if issues entered into the corrective action program were adequately addressed.

b. Findinqs No findings were identified.

.2.1.7 Diesel-Driven Fire Pump (00P51 1)

a. Inspection Scope

The team inspected the diesel-driven fire pump to evaluate whether it was capable of meeting its operational requirements assumed in the LGS PRA model. The team reviewed applicable portions of the UFSAR, Technical Requirements Manual, PRA model, and the DBD to identify the requirements for the fire pumps. The fire water system can be cross-tied to the residual heat removal (RHR) system of each unit to piovide an alternate source of water that can be injected to the reactor vessel via the low pressure coolant injection (LPCI) line. The team also reviewed the human error probability analysis to determine how quickly the operators were credited with aligning the fire water system as an alternate injection to the reactor vessel. The team interviewed licensed operators, reviewed associated abnormal procedures, and observed an operator simulate the required actions of the procedure in the field to evaluate the ability of the operators to perform the required actions. Finally, the team reviewed system health reports, preventive and corrective maintenance work orders, test results, and corrective action condition reports to determine if Exelon appropriately identified, evaluated, and corrected deficiencies.

b. Findinqs No findings were identified.

.2.1.8 Emerqencv Service Water Pump 'A'

a. Inspection Scope

The team inspected the'A'emergency service water (ESW) pump to evaluate if it was capable of performing its design basis function. Specifically, the team evaluated whether the pump capacity was sufficient to provide adequate flow to the safety-related components supplied by the ESW system during design basis events. Design calculations were reviewed to assess available pump NPSH and to evaluate the capability of the pump to provide flow to served components. Additionally, the team evaluated the ability of the ESW system to supply non-essential components that could be served by the ESW system as prescribed by the emergency operating procedures.

The team also evaluated changes that impacted flow requirements to individual ESW system loads due to changes in fouling factors and revised heat load requirements for components. The team reviewed ESW pump in-service testing (lST) results and ESW system flow verification tests to determine if adequate system flow rate was available.

Specifically, the team reviewed pump data trends for vibration, and pump differential pressure and flow rate test results to verify acceptance criteria were met and acceptance limits were adequate to ensure that potential degradation of the pump would not result in the system becoming inoperable. Further, the flow measurement uncertainties, including flow element, flow transmitter and other loop components, were evaluated to ensure that flow measurement accuracies conformed to required standards. The team also interviewed the system engineer and performed a walkdown of the pump to evaluate its material condition and assess the pump's operating environment. Finally, the team reviewed condition reports to determine if the corrective actions adequately addressed the identified deficiencies.

b. Findinqs No findings were identified.

.2.1.9 Residual Heat Removal Service Water Pump 'B'

a. Inspection Scope

The team inspected the'B' residual heat removal service water (RHRSW) pump (0P8506) to determine if it was capable of performing its design basis function. The team reviewed applicable portions of the UFSAR, and DBD to identify the design basis requirements for the pump. Design calculations were reviewed to assess available pump NPSH and determine required system flows. The team evaluated whether the pump capacity was sufficient to provide adequate flow to the RHR heat exchanger (HX)during design basis events and for direct injection via the RHR cross-tie during accident mitigation. The team also reviewed RHRSW pump IST results and system flow verification tests to verify adequate system flow rate. Specifically, the team reviewed pump data trends for vibration, and pump differential pressure and flow rate test results to verify acceptance criteria were met and the acceptance limits were adequate to ensure pump degradation would not result in the system becoming inoperable. Further, the flow measurement uncertainties, including flow element, flow transmitter and other loop components, were evaluated to ensure that flow measurement accuracies conformed to required standards. The team evaluated completed design modification documents to determine if the changes impacted the design or licensing basis requirements. The team also discussed the pump performance with the system engineer and performed a walkdown of the pump to evaluate its material condition and assess the pump's operating environment. Finally, the team reviewed condition reports to determine if the corrective actions adequately addressed the identified deficiencies.

b. Findinos No findings were identified.

.2.1.1 0 Sprav Pond Pump House Ventilation

a. Inspection Scope

The team inspected the spray pond pump house ventilation system to determine if it could meet its required support function of controlling air temperature for the RHRSW and ESW pumps, motors, and motor control center (MCC) located in the pump house.

The team reviewed heat load calculations to determine the flow requirements for the system. The team then reviewed flow balance test procedures and results, and associated calibration procedures of the pump house instrumentation to ensure that system response to varying weather conditions demonstrated that the required air flow requirements could be achieved. The team also conducted a walkdown of the system, interviewed the system engineer, and reviewed condition reports and system health reports in order to assess the material condition of the system, and to assess Exelon's capability to identify, evaluate, and correct problems' b. Findinqs No findings were identified.

2.1.11 Coolinq Tower

a. Inspection Scope

The team inspected the station design features credited to mitigate flooding following the assumed failure of the station cooling towers. The team reviewed the station's analysis that evaluated the potential impact of flooding due to the failure of the cooling tower to determine the assumed flooding paths, flow rates, and total volume of water assumed in the analysis. The team also reviewed the UFSAR and flooding calculations to determine the expected flood levels and potential resultant impact on safety-related components.

Additionally, the team conducted a station walkdown of the cooling towers, turbine building, and the external station grounds to determine if the assumptions in the analysis were consistent with the as-found configuration. Finally, the team interviewed station engineers and conducted a table{op discussion with area schematics and building layouts to evaluate if the expected flood flow paths were reasonable.

b. Findinqs No findings were identified.

.2.1.1 2 Unit 2 Residual Heat Removal Pump 'B'

a. Inspection Scope

The team inspected the Unit 2 RHR pump 'B' to determine if the pump was capable of performing its design basis function of providing adequate cooling to restore and maintain level in the vessel following a postulated loss-of-coolant accident (LOCA)condition and cool suppression pool water during design basis events. The team reviewed applicable portions of the UFSAR, TSs, design calculations, and procedures to identify the pump design basis requirements. The team also reviewed recent pump surveillance test results to ensure the pump performance remained consistent with design basis requirements and to determine whether the results were consistent with specified test acceptance criteria. The team reviewed calculations to ensure design flow and pressure requirements were appropriately translated into acceptance criteria in pump IST procedures. The team verified that adequate NPSH for the RHR pump was available for the worst case maximum flow conditions expected during system operation.

The team reviewed system operating procedures to evaluate consistency with pump design requirements and pump limitations. Additionally, the team reviewed lubrication program guidance and oil sample results, and interviewed systems and design engineers to determine if required pump/motor lubrication was being performed. The team also conducted walkdowns of the pump to assess the material condition and to verify the installed configuration was consistent with plant drawings and the design and licensing bases. Finally, the team reviewed condition reports to identify failures or adverse conditions, and to determine whether issues were being identified and properly addressed.

b. Findinqs No findings were identified.

.2.1.1 3 Unit 1 Main Steam lsolation Valve HV-041-'1F0288

a. Inspection Scope

The team inspected the Unit 1 main steam isolation valve (MSIV) (HV-041-1F0288) to determine if the valve was capable of performing its design basis function to close and isolate the reactor vessel during a design basis event. The team reviewed the UFSAR and DBD to identify the design basis requirements for the air-operated valve (AOV). The team reviewed calculations for valve stem thrust and actuator inputs to ensure that the AOV was capable of operation under the worst-case line pressure and differential pressure conditions. The team reviewed surveillance test procedures to verify that design basis stroke times were enveloped by test acceptance criteria, and that the leak rate through the valve when isolated was consistent with 10 CFR Part 50, Appendix J requirements. The team interviewed system and design engineers to ensure I

recommended maintenance had been established through the preventive maintenance program and design changes had been satisfactorily implemented. Finally, the team reviewed condition reports to identify failures or adverse conditions, and to assess Exelon's capability to identify, evaluate, and correct problems.

b. Findinqs No findings were identified.

.2.1.1 4 Emerqencv Diesel Generator D23 Mechanical SvsteJrns

a. Inspection Scope

The team inspected the D23 emergency diesel generator (EDG) mechanical systems to determine if they were capable of operating during design basis events. Specifically the team evaluated the capabilities of the fuel oil and fuel oil transfer, lube oil, starting air, intake, exhaust, and jacket water cooling systems to ensure the proper operation of the EDG during a design basis event. The team reviewed the UFSAR, the TSs, operating procedures, and DBDs to identify the design basis requirements for these systems. The team reviewed EDG surveillance test results and operating procedures to ensure the mechanical support systems were operating as designed and within their vendor design limits. The team reviewed fuel oil consumption calculations to verify TS requirements were adequate to meet design basis loading conditions. The team reviewed lube oil sample results to verify proper lubrication of system components, and interviewed engineering staff to ensure timely analysis for wear was being performed. In addition, the team interviewed system engineers to determine past performance and operation of the EDGs. The team performed several field walkdowns of the D23 to assess the

'

material condition and system alignments including localand remote EDG controlswitch positions. Finally, the team reviewed the EDG maintenance history and system health reports as well as selected issue reports to determine the overall health of the D23 EDG systems and to determine if problems were properly identified and corrected.

b. Findinqs No findings were identified.

.2.1.1 5 4160V Safequards Bus D2?

a. fnspection Scope The team inspected the Unit 2-4160Yac safeguards bus (D22) to determine if it was capable of operating during design basis events. The team reviewed selected calculations for electrical distribution system load flow/voltage drop, degraded voltage protection, short-circuit protection, and electrical protection and coordination to determine the adequacy and appropriateness of design assumptions and calculations.

The team evaluated if bus capacity was exceeded and determined if bus voltages remained above minimum acceptable values under design basis conditions. The team specifically reviewed degraded voltage protection schemes to verified that degraded and b.

.1 loss of voltage relays were set in accordance with calculation assumptions, and that the

associated calibration procedures were consistent with those assumptions and setpoint accuracy requirements. Finally, the team evaluated selected portions of the licensee response to NRC Generic Letter (GL) 2006-02 to determine if LGS's interface and coordination with the transmission system operator for offsite voltage requirements and notification setpoints were being maintained in accordance with their GL response and that those limits were consistent with design assumptions.

The team also reviewed switchgear protective device settings and breaker ratings to ensure that selective coordination was adequate for protection of connected equipment during short-circuit conditions. To ensure that breakers were maintained in accordance with industry and vendor recommendations the team reviewed the preventive maintenance inspection and testing procedures and testing results. The 125 Vdc control power voltage calculations were reviewed to ensure adequate voltage would be available for the breaker closure and opening control circuit components and the breaker spring charging motors. Additionally, the team performed a visual inspection of observable portions of the safety-related 4kV switchgear to assess the installed configuration, material condition, environmental condition, and potential vulnerability to hazaids. Finally, system health reports, component maintenance history, and licensee condition reports were reviewed to determine whether issues were being identified and properly addressed.

Findinqs lntroduction. The team identified a finding of very low safety significance (Green)involving A non-cited violation of 10 CFR Part 50, Appendix B, Criterion lll, "Design Control.; Specifically, Exelon did not verify that adequate voltages would be supplied to safety-related equipment powered from the 4kV, 480 Vac, and 120 Vac distribution systems during a design basis loss-of-coolant accident when connected to offsite power.

Description.

The team reviewed Exelon's calculation 6300E.20, "Voltage Regulation Study," Revision 12, which modeled the voltage transient that would occur during design basis events. The team determined Exelon used this calculation to evaluate the offsite power sources' capability to supply adequate voltage to loads on the 4kV and 480 Vac bus levels. The team's review identified several examples of non-conservative inputs and methodologies in the calculation. Specifically, the team identified;

. Exelon's evaluation of the starting transient caused when the emergency core cooling system (ECCS) loads were placed on the 4kV and 480 Vac busses during a design basis event assumed a non-conservative initial voltage on the bus.

SpeCifically, the team found that Exelon assumed that the 4kV supply transformer's tap changer would be in a higher boost position at the beginning of the event because the calculation assumed post-reactoriturbine trip offsite power voltage was present on the bus prior to the beginning of the event. The team determined that this assumption placed the tap changer in a non-conservative pre-accident position resulting in a higher post-accident voltage on the bus.

Exelon assumed 1 second for th4 starting and acceleration time of 480 Vac motors.

The team found that normal acceleration times for NEMA B motors are approximately 5 seconds. The team determined that the longer motor starting time would result in a lower voltage to the terminals of Safety-related motors during a design basis event.

Exelon did not include the impedFnce of the thermal overload relays in the starting circuit of safety-related motors. The team determined that the impedance of the relays increase the voltage drop to the terminals of safety-related motors during a design basis event.

The team also reviewed calculations and analyses performed to evaluate voltages at the 4kV bus and 480 Vac motor control 0enters during design basis load sequencing with the 4kV safety-buses operating at the degraded voltage dropout setpoint. Following this review the team questioned what the voltage was at the motor terminals of the supplied loads. The team found that; Exelon had not evaluated what the voltage would be to the 480 Vac continuous duty motors and 480 Vac static loads ito ensure that they would be operated within the manufacturer ratings for both starting and running conditions.

Exelon had not performed an evhluation that determined voltages to components supplied by 120 Vac MCC contrdl power during the transients. Exelon provided the team electrical calculation 6470S.25, "Control Circuit Maximum Cable Length - 480V MCC" as their evaluation of 120 Vac loads. The team found that the calculations determined the maximum cable lengths for the design of the 120 Yac systems and assumed a minimum steady-state voltage of 432 Vac at the motor control centers.

The team found that this analysis did not determine if allthe installed cable lengths were less than the length assumed in the analysis nor did it evaluate if all MCC bus voltages were above 432 Vac. Additionally, the team identified that all circuit impedances had not been accounted for in the analysis.

Prior to the end of the on-site inspeqtion Exelon provided the inspection team preliminary analysis and evaluations of the expdcted voltage conditions at the 4kV, 480 Vac, and 12OYac levels which determined thdt emergency core cooling system (ECCS) equipment remained operable. Several conditibns reports were created in order to fully evaluate the impact of these non-conservative assumptions on all busses and to perform adequate analysis of the voltage conditions to loads at all voltage levels in order to justify compliance with design and licensing basis requirements. The team reviewed the results of the initial assessments and deterfnined the assessment was reasonable.

Analvsjs. The team determined that the failure to verify and ensure adequate voltages to safety-related equipment and components powered from the 4kV, 480vac, and 12OVac distribution systems during a design basis accident with offsite power available was a performance deficiency. This issue was more than minor because it was similar to IMC 0612, Appendix E, "Examples of Minror lssues," Example 3.j, in that the design analysis deficiency resulted in a condition where the team had reasonable doubt of operability of the safety-related busses. ln addition, it was associated with the design control attribute

,2 of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. In accordance with Inspection Manual Chapter 0609, Appendix A, "The Significance Determination Process (SDP) for Findings At-Power," Exhibit 2 - Mitigating Systems Screening Questions, the team determined that it was of very low safety significance (Green) because it was a design or qualification deficiency confirmed not to result in loss of operability or functionality. Specifically, the licensee's interim analysis, evaluations and operability determination demonstrated the operability of offsite power during a loss-of-coolant accident, in that the components would be able to perform their safety function. This finding had a cross-cutting aspect in the area of Human Performance, Resources, because Exelon did not provide complete, accurate and up{o-date design documentation to plant personnel and because these calculations had been recently revised. (lMC 0310, H.2(c))

Enforcement.

The team identified a non-cited violation of 10 CFR Part 50, Appendix B, Criteiion lll, "Design Control," which states, in part, design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program. Contrary to the above, prior to September 2012, Exelon did not verify or check the adequacy of design voltages to safety-related emergency core cooling system equipment powered from the 4kV, 480vac, and 120Vac distribution systems with offsite power available during design basis events. Because this finding was determined to be of very low safety significance (Green) and was entered into the ficensee's corrective action program (CR 01418917,01419420, and 01419423), this violation is being treated as a non-cited violation consistent with Section 2.3.2.a of the NRC Enforcement Policy. (NCV 05000352/35312012007-01, Inadequate Evaluation of Voltage to Safety-Related Equipment with Offsite Power Available)lntroduction. The team identified a finding of very low safety significance (Green)irvoWing a non-cited violation of Limerick Generating Station License Condition 2.C.(3),

"Fire Protection," which states Exelon Generation Company shall implement and maintain in effect all provisions of the approved Fire Protection Program as described in the UFSAR. Specifically, the team found that Exelon's multiple high impedance fault (MHIF)analysis, developed to verify that post-fire safe shutdown equipment would remain available, used non-conservative overcurrent trip setpoints for 480 Vac overcurrent protection devices.

Description.

The team evaluated the overcurrent protection design for 480 Vac loads on motor control centers (MCC). The team determined that the overcurrent protection was provided by a combination of a motor controller consisting of an instantaneous magnetic trip device (IMTD) in the molded case circuit breaker (MCCB) and a separate thermal overload (TOL) relay. The team determined that these two devices were designed such that the TOL relay protected the MCC from overload current of a magnitude greater than motor starting currents up to motor locked rotor current and the IMTD protected the MCC from overcurrent conditions due to short circuit conditions.

The team also reviewed the UFSAR and determined that Section 8.3.1.1.2.1 1 stated that the electric distribution system was selectively coordinated to isolate a fault to minimize effects on the system, and all Class 1E (safety-related) and Non-Class 1E (non-safety related) circuits were individually protected and coordinated by individualfault-actuated protection devices. Additionally, Section 9A.6.1.1 stated that individual circuit breakers would clear a fault prior to the operation of the source breaker and Section 9A.6.4 described a post-fire safe shutdown analysis for MHIFs stating the setpoint of the TOL relay was used to ensure that fire induced MHIF currents below the trip settings associated with each circuit breaker would not collectively propagate to upstream supply breakers during a fire.

The team evaluated the 480 volt motor circuits to determine if the overcurrent protection for the circuit provided by the fMTD and TOL relay met the USFAR described functions.

The team determined that the TOL relays protected motors against overload currents (i.e., prolonged overcurrent up to motor locked rotor current) and instantaneous magnetic trip devices protected the circuit cables against overcurrent from short circuit faults. The team identified that the TOL manufacturer and breaker manufacturer also specified that the TOL should be designed to protect against short circuits per the National Electric Code (NEC) guidance. The team reviewed NEC Section 430-52, "Rating or Setting for Individual Motor Circuit," which described how to coordinate the TOL and IMTD to provide protection for both the motor overload and the fault currents above the rating of the TOL. The team found that NEC required that in order to provide protection the two devices must be coordinated. The NEC states the setting of the instantaneous trip should be greater than 700 percent but shall not exceed 1300 percent of the motor full load amperage (FLA) and that the TOL relays should be sized to be rated to trip fault currents up to 10 times motor FLA.

The team reviewed the MCC load tabulation drawings to determine the overcurrent trip setpoints of the TOL relays and IMTD to assess whether the upstream source breakers were adequately protected, as described in the UFSAR. The team determined the TOL relay setpoints were selected based on motor FLA and were designed to interrupt current up to 10 times the value of the FLA. The team also reviewed maintenance procedure M-C-700-232, "Testing and Control of 600V Class 1E MCC Circuit Breakers and Setpoints," used to establish the initial setpoint of new MCCB IMTD and for routine verification of MCCB IMTD setpoints. The team identified that the acceptance criteria for the IMTD trip test had a tolerance of +40 percent, -0 percent of the value specified in the MCC load tabulation drawing. The team also noted that the trip setting value required by the MCC load tabulation could not be specifically established because the breaker trip setpoint for the IMTD was established by a discrete switch located on each MCCB, and the MCCB switch setpoint values were different than the values specified by the MCC load tabulation.

The team's review of the M-C-700-232 procedure determined that the as-left trip settings for MCCBs could be nominally 20 percent to 40 percent greater than the design trip values, as specified in the MCC load tabulation. The team found that for some breakers this value would result in the instantaneous trip setpoint exceeding 1300 percent of FLAs as specified in the NEC guidance. As a result the team concluded that there was a gap in the overcurrent protection between the TOL's maximum current interrupting capacity and the MCCB instantaneous magnetic trip setpoint for some 480 volt motor circuits and fault currents could propagate past individual MCCBs and potentially allow a combination of fault currents to overload and trip an MCC source breaker.

Finally, the team reviewed 6900E.21, "Multiple High lmpedance Fault Study,"

Revision 14 and identified that some assumed fault currents used in the analysis were inconsistent with the actual MCCB trip values, and in some cases non-conservative.

Specifically, the team found that in some cases the TOL maximum setpoint was used in the analysis. For other breakers the team identified the MCCB design instantaneous trip value as specified in the load tabulation was used. In both cases, the team identified examples where the assumed fault values were non-conservative because higher fault currents could exist based on the actual breaker trip setpoints before the feeder protection device would interrupt the fault. Additionally, the team noted that the use of IMTD setpoint values was inconsistent with the description of the analysis in the UFSAR, which stated that the TOL setpoint had been used for the analysis. Exelon entered this issue into their corrective action program and assessed the effects of using worst case or actual as-left trip settings on the MHIF analysis. Based on the re-analysis, Exelon concluded that MHIFs would not result in an overcurrent condition to upstream supply breakers. The team found Exelon's analysis reasonable.

Analvsis. The team determined that Exelon's selection of MCCB trip values for use in the MHIF analysis was non-conservative and was a performance deficiency.

Specifically, the post-fire safe shutdown MHIF analysis did not use worst case or maximum fault current to verify fire induced fault currents propagating past branch feeder MCCBs would not cause the MCC source breaker to overload and trip. This issue was more than minor because it was similar to IMC 0612, Appendix E, "Examples of Minor lssues," Example 3.j, in that the design analysis deficiency resulted in a condition where the team had reasonable doubt of operability of the MCC during a fire.

In addition, this issue was associated with the Fire Protection attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The team performed a Phase 1 SDP screening, in accordance with IMC 0609, Appendix F, "Fire Protection Significance Determination Process." This finding affected the post-fire safe shutdown category, and was screened to very low safety significance (Green) because it had a low degradation rating. A low degradation rating was assigned because Exelon's re-evaluation, using as-found or worst case trip setpoints, determined that the equipment remained operable.

Specifically, MCC source breakers would be capable of meeting their design basis function when exposed to MHIF currents at the worst case IMTD value. fn addition, this issue did not affect the likelihood that a fire might occur. The team concluded that the performance deficiency was reasonably within Exelon's ability to foresee and prevent.

This finding did not have a cross-cutting aspect because it was not considered indicative of current licensee performance because it was an original design issue.

Enforcement.

Limerick Generating Station License Condition 2.C.(3), "Fire Protection,"

states Exelon Generation Company shall implement and maintain in effect all provisions of the approved Fire Protection Program as described in the Updated Final Safety

Analysis.

Contrary to the above, prior to October 2012, Exelon did not ensure allowable as-left field setpoints for MCCBs were used in the design analysis described in the FSAR in order to ensure selective coordination of the distribution system was established and maintained on the Class 1E electrical distribution system during fire safe shutdown conditions. Because this issue was of very low safety significance (Green)and Exelon entered this issue into their corrective action program (CR 1422536), this finding is being treated as a non-cited violation consistent with Section 2.3.2.a of the NRC Enforcement Policy. (NCV 05000352/35312012007 -02, 480V Motor Control Gircuit Breaker Overcurrent Protection)

.2.1.1 6 Station Auxiliarv Bus 20

a. Inspection Scope

The team inspected the 13kv station auxiliary bus (Bus 20) to verify it was capable of operating during design basis events. The team reviewed selected calculations for electrical distribution system load flow/voltage drop, and electrical protection and coordination to determine the adequacy and appropriateness of design assumptions.

The team also reviewed the calculations to determine if bus capacity would be exceeded and if bus voltages would remain above minimum acceptable values under design basis conditions. The switchgear's protective device settings and breaker ratings were reviewed to ensure that selective coordination was adequate for protection of connected equipment during short-circuit conditions. To ensure that breakers were maintained in accordance with industry and vendor recommendations, the team reviewed the preventive maintenance inspection and testing procedures to determine if they met industry and vendor recommendations. The team performed a visual non-intrusive inspection of observable portions of the 13.2kV switchgear to assess the installation configuration, material condition, and potential vulnerability to hazards. Finally, system health reports, component maintenance history, and licensee condition reports were reviewed to identify adverse conditions, and to assess Exelon's capability to identify, evaluate, and correct problems.

b. Findinqs No findings were identified.

.2.1.1 7 Emeroencv Diesel Generator D12. Electrical

a. Inspection Scope

The team inspected the D12 EDG electrical systems to verify they were capable of operating during design basis events. The team reviewed loading and voltage regulation calculations, including the bases for brake horsepower values used, to verify that design bases and design assumptions have been appropriately translated into the design calculations. The team reviewed analyses and surveillance testing to assess EDG capability under required operating conditions. The team also reviewed calculations, operating procedures, and technical evaluations to verify that steady-state and transient loading were within design capabilities, adequate voltage would be present to start and operate connected loads, and operation at maximum allowed frequency would be within the design capabilities. The team reviewed the EDG load sequence time delay I

setpoints, calibration intervals, and results of the last calibration for accuracy to determine if the results were consistent with the design requirements. The team also performed a visual inspection of the EDG to assess the installation configuration, material condition, and potential vulnerability to hazards.

The team reviewed protection, coordination, and short-circuit calculations to verify that the EDG was adequately protected with properly set protective devices during test mode and emergency operation under worst case fault conditions. The team's review included the interfaces and interlocks associated with 4.16kV D12 safeguards bus, including voltage protection schemes that initiate connection to the EDG, to verify adequacy. The team reviewed the setpoint calculations, calibration procedures, and the latest surveillance test results for the voltage detection relays, including applicable time delays, to ensure test acceptance criteria and results were consistent with design assumptions.

Additionally, the team reviewed the 125Vdc voltage calculations to determine if adequate voltage would be available to the breaker control circuit components and the breaker spring charging motor so that the EDG supply breaker would open and close as required. Finally, system health reports, component maintenance history, and licensee condition reports were reviewed to identify adverse conditions, and to assess Exelon's capability to identify, evaluate, and correct problems.

b. Findinqs No findings were identified.

.2.2 Review of lndustrv Operatino Experience and Generic lssues (5 samples)

The team reviewed selected OE issues for applicability at the Limerick Generating Station. The team performed a detailed review of the OE issues listed below to verify that Exelon had appropriately assessed potential applicability to site equipment and initiated corrective actions when necessary.

.2.2.1 NRC lnformation Notice 2010-17: Common Cause Failure of Boilinq-Water Reactor

Recirculation Pumps with Variable Speed Drives

a. Inspection Scope

The NRC issued Information Notice (lN) 2010-17 which described common cause failure of all recirculation pumps during an electrical transient on the offsite power grid. The failures were due to the design of the recirculation pump control circuits. The lN identified considerations licensees should evaluate in their design when upgrading their current systems to digitalvariable speed drives (VSD). The team reviewed Exelon's actions relative to the considerations identified in the lN to ensure Exelon had performed appropriate evaluations of common cause failures for the adjustable speed drive (ASD)system installed in LGS Unit 1. The team also reviewed the ASD modification package, the LGS ASD specifications, vendor evaluation documents, industry documents, drawings, and ASD system testing to ensure common cause failures were appropriately evaluated. The team reviewed system health reports, corrective action documents and held discussions with site engineers to determine if any common mode failures had occurred. Additionally, the team independently walked down accessible portions of the ASD system installed in LGS Unit 1 to assess the material condition of the installed system, controls, and components.

Findinqs No findings were identified.

NRC lnformation Notice 2012-14: Motor-Operated Valve Inoperable Due to Stem-Disc Seoaration lnspection Scope The team selected lN 2012-14tor a detailed review. The team evaluated Exelon's applicability review and disposition of NRC lN 2012-14. The NRC issued this lN to inform licensees about an event where a motor-operated valve (MOV) failed at the connection between the valve stem and disc. The team reviewed Exelon's actions relative to the conditions described within the lN to ensure Exelon had performed appropriate evaluations for Limerick.

Findinos No findings were identified.

.2.2.3 NRC lnformation Notige 2007-27: Recurrinq Events Involvinq Emerqencv Diesel

Generator Operabilitv

a. Inspection Scope

The team selected lN 2007-27, "Recurring Events Involving Emergency Diesel Generator Operability," for a detailed review. The team reviewed Exelon's evaluation of the lN and the associated corrective actions to determine if Exelon adequately addressed the concern which was discussed in the lN. The team also reviewed Exelon's EDG system health reports, EDG condition reports and work orders, leakage database, and surveillance test results to verify that Exelon appropriately addressed identified EDG deficiencies. Additionally, the team walked down six of the eight Unit 1 and Unit 2 EDGs on several occasions during the inspection period to look for indications of vibration-induced degradation on EDG piping and tubing, and for any type of leakage (air, fuel oil, lube oil, and/or jacket water). The team performed these walkdowns both pre and post-operation of monthly EDG surveillance runs to determine if Exelon maintained appropriate configuration control and appropriately identified deficiencies.

b. Findinqs No findings were identified.

b.

a.

b.

.2.2.4 NRC lnformation Notice 2010-27: Ventilation Svstem Preventive Maintenance and

Desiqn lssueq

a. Inspection Scope

The team reviewed Limerick's evaluation of lN 2010-27,"Yentilation System Preventive Maintenance and Design lssues," and the associated corrective action report that addressed the site response to the operating experience. The NRC issued the lN to alert licensees of recently identified ventilation system preventive maintenance and design issues. The team reviewed Exelon's evaluation of the potential impact of the identified issues and determined that none of the identified issues in the lN were directly applicable to Limerick (design and station layout precluded such issues). The team reviewed Exelon's actions to revise their maintenance procedures to perform more frequent lubrication of heating, ventilation, and air conditioning system dampers located in the spray pond pump house to address a weakness identified during the review of the tN.

b. Findinqs No findings were identified.

.2.2.5 NRC lnformation Notice 2011-12: Reactor Trips Resultinq from Water lntrusion into

Electrical Equipment

a. Inspection Scope

The team reviewed lN 201 1-12 which described several events where water leaks had resulted in electrical faults and grounds resulting in reactor trips. The lN additionally described the trip of an EDG due to an Agastat relay timing out prematurely during one event. The lN stated that the relays were significantly beyond the vendor recommended replacement interval of 10 years contributing to their failure during the event. The team reviewed Exelon's evaluation of lN 2011-12to ensure that the conditions and associated deficiencies described in the lN were adequately reviewed and similar deficiencies identified at LGS were adequately addressed.

b. Findinqs No findings were identified.

OTHER ACTIVITIES

4OA2 ldentification and Resolution of Problems (lP 71152)

a. Inspection Scope

The team reviewed a sample of problems that Exelon had identified and entered into their corrective action program. The team reviewed these issues to verify an appropriate b.

threshold for identifying issues and to evaluate the effectiveness of corrective actions. In addition, corrective action documents written on issues identified during the inspection were reviewed to verify adequate problem identification and incorporation of the problem into the corrective action program. The specific corrective action documents that were sampled and reviewed by the team are listed in the attachment.

Findinqs No findings were identified.

Meetinqs. includinq Exit On September 28, 2012, the team presented the preliminary inspection results to Mr. T.

Dougherty, Site Vice President, and other members of the LGS staff. Following additional review, including an onsite inspection on October 25, 2Q12, and discussion with the Office of Nuclear Reactor Regulation Electrical Branch staff, the final inspection results were discussed with Mr. Wayne Lewis, Senior Manager Design Engineering and other members of the LGS staff on December 17,2012. The team verified that none of the information in this report is proprietary.

4046 ATTACHMENT

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee Personnel

T. Dougherty Vice President

D. Doran

Director of Engineering

W. Lewis

Senior Manager, Engineering Design

R. Dickinson

Manager, Regulator Assurance

R. George

Manager, Electrical Design

E. Hosterman Design Engineer

E. Weber

Design Engineer

J. Bendyk

System Manager

J. Berg

System Manager

P. Soni

Design Engineer

R. Harding

Licensing Engineer

R. Schwab

Design Engineer

T. Johnston

Design Engineer

LIST OF ITEMS

Opened and Closed

05000352/35312012007-01 NCV

05000352/35312012007-02 NCV Inadequate Evaluation of Voltage to Safety-Related Equipment with Offsite Power Available (Section 1R21.2.1. 1 5. 1 )

480V Motor Control Circuit Breaker Overcurrent Protection (Section 1R21.2.1.15.2)