IR 05000346/2012008

IR 05000346-12-008, 08/13/2012 - 11/02/2012; Davis-Besse Nuclear Power Station; Component Design Bases Inspection (CDBI)

ML12339A169
Person / Time
Site:	Davis Besse
Issue date:	12/03/2012
From:	Ann Marie Stone NRC/RGN-III/DRS/EB2
To:	Lieb R FirstEnergy Nuclear Operating Co
Andrew Dunlop
References
IR-12-008
Download: ML12339A169 (30)

Text

ber 3, 2012

SUBJECT:

DAVIS-BESSE NUCLEAR POWER STATION COMPONENT DESIGN BASES INSPECTION 05000346/2012008(DRS)

Dear Mr. Lieb:

On November 2, 2012, the U.S. Nuclear Regulatory Commission (NRC) completed a Component Design Bases Inspection (CDBI) at your Davis-Besse Nuclear Power Station.

The enclosed report documents the results of this inspection, which were discussed on November 2, 2012, with Mr. R. Lieb, on September 14, 2012, with Mr. B. Allen, and other members of your staff.

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

The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel.

No findings were identified during this inspection.

In accordance with 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 public inspection in the NRC Public Document Room or from the Publicly Available Records System (PARS)

component of NRC's Agencywide Document Access and Management System (ADAMS).

ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/RA/

Ann Marie Stone, Chief Engineering Branch 2 Division of Reactor Safety Docket No. 50-346 License No. NPF-3

Enclosure:

Inspection Report 05000346/2012008(DRS)

w/Attachment: Supplemental Information

REGION III==

Docket No: 50-346 License No: NPF-3 Report No: 05000346/2012008(DRS)

Licensee: FirstEnergy Nuclear Operating Company (FENOC)

Facility: Davis-Besse Nuclear Power Station Location: Oak Harbor, OH Dates: August 13, 2012, through November 2, 2012 Exit Date: November 2, 2012 Inspectors: A. Dunlop, Senior Engineering Inspector, Lead M. Jones, Engineering Inspector, Mechanical C. Zoia, Operations Inspector G. Morris, Electrical Contractor N. Della Greca, Electrical Contractor M. Yeminy, Mechanical Contractor Approved by: Ann Marie Stone, Chief Engineering Branch 2 Division of Reactor Safety Enclosure

SUMMARY

IR 05000346/2012008, 08/13/2012 - 11/02/2012; Davis-Besse Nuclear Power Station;

Component Design Bases Inspection (CDBI).

The inspection was a 3-week onsite baseline inspection that focused on the design of components. The inspection was conducted by regional engineering inspectors and three consultants. No findings were identified by the inspectors. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 4, dated December 2006.

NRC-Identified

and Self-Revealed Findings No findings were identified.

Licensee-Identified Violations

No violations were identified.

REPORT DETAILS

1R21 Component Design Bases Inspection

.1 Introduction

The objective of the Component Design Bases Inspection is to verify the design bases have been correctly implemented for the selected risk significant components and the operating procedures and operator actions are consistent with design and licensing bases. As plants age, their design bases may be difficult to determine and an important design feature may be altered or disabled during a modification. The Probabilistic Risk-Assessment (PRA) model assumes the capability of safety systems and components to perform their intended safety function successfully. This inspectable area verifies aspects of the Initiating Events, Mitigating Systems, and Barrier Integrity cornerstones for which there are no indicators to measure performance.

Specific documents reviewed during the inspection are listed in the attachment to the report.

.2 Inspection Sample Selection Process

The inspectors used information contained in the licensees PRA and the Davis-Besse Nuclear Power Station Standardized Plant Analysis Risk Model to identify a scenario to use as the basis for component selection. The scenario selected was a station blackout event. Based on this scenario, a number of risk significant components were selected for the inspection.

The inspectors also used additional component information such as a margin assessment in the selection process. This design margin assessment considered original design reductions caused by design modification, power uprates, or reductions due to degraded material condition. Equipment reliability issues were also considered in the selection of components for detailed review. These included items such as performance test results, significant corrective actions, repeated maintenance activities, Maintenance Rule (a)(1) status, components requiring an operability evaluation, NRC resident inspector input of problem areas/equipment, and system health reports.

Consideration was also given to the uniqueness and complexity of the design, operating experience, and the available defense in depth margins. A summary of the reviews performed and the specific inspection findings identified are included in the following sections of the report.

The inspectors also reviewed procedures and modifications associated with the selected components. In addition, the inspectors selected operating experience issues associated with the selected components.

This inspection constituted 22 samples as defined in Inspection Procedure 71111.21-05.

.3 Component Design

a. Inspection Scope

The inspectors reviewed the Updated Safety Analysis Report (USAR), Technical Specifications (TS), design basis documents, drawings, calculations and other available design basis information, to determine the performance requirements of the selected components. The inspectors used applicable industry standards, such as the American Society of Mechanical Engineers (ASME) Code, Institute of Electrical and Electronics Engineers (IEEE) Standards and the National Electric Code, to evaluate acceptability of the systems design. The NRC also evaluated licensee actions, if any, taken in response to NRC issued operating experience, such as Bulletins, Generic Letters (GLs),

Regulatory Issue Summaries (RISs), and Information Notices (INs). The review was to verify the selected components would function as designed when required and support proper operation of the associated systems. The attributes needed for a component to perform its required function include process medium, energy sources, control systems, operator actions, and heat removal. The attributes to verify the component condition and tested capability was consistent with the design bases and was appropriate may include installed configuration, system operation, detailed design, system testing, equipment and environmental qualification, equipment protection, component inputs and outputs, operating experience, and component degradation.

For each of the components selected, the inspectors reviewed the maintenance history, preventive maintenance activities, system health reports, operating experience-related information, vendor manuals, electrical and mechanical drawings, and licensee corrective action program documents. Field walkdowns were conducted for all accessible components to assess material condition and to verify the as-built condition was consistent with the design. Other attributes reviewed are included as part of the scope for each individual component.

The following 16 components were reviewed:

• Turbine Driven Auxiliary Feedwater (AFW) Pump (P14-2): The inspectors reviewed design calculations and site procedures to verify the design bases and design assumptions were appropriately translated into these documents. Design and operational requirements were reviewed with respect to steam supply, pump flow rate, developed head, achieved system flow rate, net positive suction head (NPSH), and minimum flow requirements. The inspectors reviewed the adequacy of assumptions, limiting parameters, the pumps protection from the formation of air vortexes, and the adequacy of its suction sources (condensate storage tank and service water discharge piping). Test procedures and recent test results were reviewed against design basis documents to verify the acceptance criteria for tested parameters were supported by calculations or other engineering documents and validated component operation under accident and transients. This included reviewing the adequacy of the new pump baseline for inservice testing (IST). The inspectors reviewed operating as well as emergency operating procedures to verify selected operator actions could be accomplished.

Additionally, the inspectors reviewed control schematics to verify system operation complied with the system design requirements.

• AFW Flow Control Valve (FV6451): Design drawings and vendor documents were reviewed to verify the installed configurations would support the design basis function under accident conditions and had been maintained to be consistent with design assumptions. The inspectors compared valve test data with the design requirements to verify valve performance was adequate. The inspectors reviewed design documents to ascertain that the valve was capable of modulating AFW flow rate as required and that its motive power was capable of this modulation during all design basis conditions. Control logic diagrams were reviewed to verify the controls and interlocks were consistent with the design-basis performance requirements and operating procedures. Additionally, the inspectors reviewed instrument loop diagrams and instrument calibration tests to confirm the instruments were operating in accordance with design requirements and were capable of providing the correct control signals under design basis conditions. In particular, the inspectors reviewed environmental qualification requirements and environmental qualification test results to confirm the valve and associated instrumentation could perform their intended function under design basis conditions.

• AFW Pump 2 to Steam Generator (SG) Isolation Valve (AF3872): The inspectors reviewed design drawings and vendor documents to verify the installed configurations would support the design basis function under accident conditions and had been maintained consistent with design assumptions. The inspectors compared valve test data with the design requirements to verify the valve performance was adequate. The inspectors reviewed calculations which determined required valve actuator torque and thrust limits and traced these requirements to the vendor supplied data. Control logic diagrams were reviewed to verify the controls and interlocks were consistent with the design-basis performance requirements and operating procedures. The inspectors reviewed system modifications to verify the modifications did not degrade the performance capability of the valves and were appropriately incorporated into relevant drawings and procedures. Control panel indicators were observed and operating procedures were reviewed to verify component operation and alignments were consistent with design and licensing bases assumptions. Test procedures and recent test results were reviewed to verify the acceptance criteria for tested parameters were supported by calculations or other engineering documents and the individual tests and analyses served to validate proper component operation.

Additionally, inspectors reviewed the control and power circuit for the valve actuator motor.

• SG 2 AFW Inlet Check Valve (AF43): Drawings and vendor documents were reviewed to verify the installed configurations would support the design basis function under accident conditions. These included check valve orientation and its distance from elbows and valves. Test procedures and recent test results were reviewed to verify the acceptance criteria for tested parameters were supported by calculations or other engineering documents and the individual tests and analyses served to validate component operation under accident conditions.

• Component Cooling Water (CCW) Pump (P43-2): Inspectors reviewed design calculations and site procedures to verify the design bases and design assumptions were appropriately translated into these documents. Design and operational requirements were reviewed with respect to pump flow rate, developed head, NPSH, minimum flow requirements, and the pumps capability to provide the flow rate required to remove the assigned heat loads. Additionally, the inspectors reviewed the testing of the pumps discharge check valves and the acceptance criteria associated with the tests. The inspectors reviewed the pumps protection from the formation of air vortices. Test procedures and recent test results were reviewed to verify the acceptance criteria for tested parameters were supported by calculations or other engineering documents and the tests and analyses served to validate component operation under accident and transients. The inspectors reviewed normal and emergency operating procedures to verify selected operator actions could be accomplished.

Additionally, the inspectors reviewed motor/pump performance curves to confirm the electrical load was correctly included in the emergency diesel generator (EDG) and bus loading calculations. The review also included motor feeder ampacity, short circuit capability, and protective relays setting to assess the adequacy of the circuit protection under normal and faulted conditions and ensure that trip setpoints would not permit the feeder breaker to trip during pump motor highest loading conditions. Available motor voltage was also reviewed to confirm the availability and capability of the pump to perform its safety function under most limiting conditions. Additionally, the inspectors reviewed motor control logic and wiring diagrams to ascertain compliance with system operation requirements.

• CCW Surge Tank (CC1643): Design calculations were reviewed to verify the design bases and design assumptions were appropriately translated into these documents. The inspectors reviewed the tanks volume and capacity with respect to water level and setpoints to ascertain whether it can support the CCW system. The inspectors reviewed the tanks overpressure protection to establish its capability to support the system under different operating conditions. The inspectors reviewed operating, as well as emergency operating procedures, to verify selected operator actions could be accomplished.

• Decay Heat Removal Heat Exchanger 1-2 CCW Discharge Isolation Valve (CC1469): The inspectors reviewed calculations and diagnostic test results to ensure the licensee has correctly translated the design basis into test procedures used to verify valve performance. The inspectors reviewed the licensees air-operated valve (AOV) program to ensure the valve was being maintained in accordance with program requirements. Additionally the inspectors reviewed electrical control schematics to verify the operation of the valve was consistent with design requirements.

• Make-up Pump 2 (P37-2): The inspectors reviewed pump calculations including the required flow rate and discharge pressure to ensure the pump was capable of performing its function under design conditions. Test procedures and results for IST were also reviewed to verify acceptance criteria were met and performance degradation would be identified. The inspector reviewed operating procedures and ensured alarms and actions were in place to prevent air entrainment from the make-up tank. The inspectors reviewed the power and control circuits, the protective device settings, and coordination with the bus feeder breaker associated with the make-up pump. The inspectors confirmed the adequacy of the voltage provided by the offsite power and the EDG.

• Main Steam Isolation Valve (MSIV) (MS100): The inspectors reviewed the MSIV to ensure the valve was capable of performing its intended safety function to close upon receiving an isolation signal. The inspectors reviewed IST stroke time data and AOV program requirements to ensure valve performance was being appropriately monitored and was capable of performing its required functions under worst cast accident conditions. The inspectors reviewed required thrust, accumulator sizing, weak link, maximum expected differential pressure, and margin calculations. Additionally, the inspectors reviewed air drop test results to verify acceptance criteria were met and performance degradation would be identified. The inspectors reviewed design voltage requirements and voltage drop calculations to confirm adequate voltage was available to the solenoid valves for the correct operation of the MSIV. The inspectors also reviewed electrical control schematics and instrument loop diagrams to verify the operation of the valve was in accordance with the system description and design requirements. Testing requirements and test results of instruments and solenoid valves were reviewed to assure the components performance was in accordance with the design requirements and expectations. In addition, the inspectors reviewed the environmental design requirements and environmental qualification test results of the MSIV solenoid valves and associated instrumentation to confirm the MSIV can perform its intended safety functions under postulated design conditions

• Reactor Coolant Pump Seal Isolation Valve (MU38): The inspectors reviewed AOV calculations and analysis to ensure the valve was capable of functioning under design conditions. These included calculations for required thrust, maximum differential pressure, and accumulator sizing. Diagnostic testing and IST surveillance results, including stroke time, seat leakage, and available thrust, were reviewed to verify acceptance criteria were met and performance degradation could be identified. The inspectors also reviewed the procedure to manually open the valve on loss of seal cooling. Additionally the inspectors reviewed electrical control schematics to verify the operation of the valve was consistent with design requirements.

• Station Blackout Diesel Generator (SBODG) (K5-3): The inspectors reviewed design basis documents, calculations, operating procedures, and a selection of completed surveillances to verify the capability of the SBODG to supply onsite electrical power during accident conditions. The inspectors reviewed the SBODG capacity: rating versus load/overload ratings, and the SBODG capability:

voltage and frequency response. The inspectors reviewed allowable high ambient temperatures for the auxiliary support equipment and SBODG derating for high combustion air temperatures. In addition, the inspectors reviewed the manual loading procedure to verify the licensee controlled loading on the SBODG. The inspectors reviewed possible loading scenarios, and SBODG electrical protection. The inspectors reviewed the ampacity and routing of the cables and cable bus connecting the SBODG to the non-safety-related buses and then onto the loads connected to the safety-related buses.

• SBODG Support Systems:

Jacket Water Cooling System: The inspectors reviewed the jacket water radiator cooling system calculations and completed test data to ensure the licensee has demonstrated the systems capability to perform its design function at maximum ambient conditions. The inspectors also reviewed control wiring diagrams to confirm the system operation conformed to the design description. Additionally, the inspectors reviewed operating procedures to ensure operator actions were in place to ensure adequate SBODG cooling.

Air Start System: The inspectors reviewed calculations supporting the installed air system capability to verify the design and assumptions were appropriately translated and supported overall system capability. The inspectors also reviewed control wiring diagrams to confirm the system operation conformed to the design description. Additionally, the inspectors verified test procedures and acceptance criteria were supported by calculations or other engineering documents to ensure the design function was maintained and that tests and/or analyses validate component operation under accident/event conditions.

Fuel Oil System: The inspectors reviewed design calculations, including NPSH and fuel oil consumption, and system operating parameters to verify the design bases and design assumptions had been appropriately translated between vendor specifications, calculations, and system procedures. Day tank level instrumentation was reviewed to verify the installed configuration would support the design function under event conditions. Test procedures were reviewed to verify the acceptance criteria were supported by calculations or other engineering documents to ensure the design and licensing bases were met, and to verify the individual test and/or analyses validated component operation under accident/event conditions.

Motor Control Center (MCC) BF81: The inspectors reviewed the auxiliary loads on MCC BF 81 supporting the station blackout system, reviewed the electrical protection for a sample of those loads, cable sizing, thermal overload relays, and protective device preventive maintenance.

SBODG 125Vdc Battery: The inspectors reviewed battery sizing and voltage drop calculation to verify the capability of the battery to supply adequate voltage to the connected DC components for the duration of the SBO. The inspectors also reviewed battery and battery charger testing procedure and test results to confirm the health and readiness of the DC system to supply power to the SBODG and its components. Additionally, the inspectors evaluated the battery change from nickel-cadmium to valve regulated lead acid to confirm the allowable battery room temperature had not been exceeded.

• 480V Substation Bus F1: The inspectors reviewed the loads capable of being powered from the SBODG, including the 480V loads on Substation Bus F1. The inspectors reviewed the power cable size selection for the motor control centers fed from Bus F1 and confirmed the adequacy of the bus voltage, the adequacy of the major protective device coordination.

• 4160V Bus D1 (D2 and D3): The inspectors reviewed a sample of the medium voltage buses related to the SBO for capacity: rating versus load/overload ratings, capability: voltage response and the circuit breaker AD213 and AD301 overload setpoints. The inspectors reviewed various contributors to a loss of offsite power and SBO initiating events. For a loss of offsite power, the inspectors reviewed the licensees input to the interface agreement with the grid operator required by NERC Reliability Standard NUC-01-02, Reliability Standard for Nuclear Plant Interface. The inspectors reviewed the condition monitoring of medium voltage cable and cable bus between the SBODG and 4160V switchgear D3.

• 125/250Vdc Batteries (2P/2N): The inspectors reviewed the battery sizing and loading calculation to verify all loads were accounted for, the loads did not exceed the battery bank capacity, and the calculated load profile bounded all accident scenarios. The inspectors also reviewed the short circuit calculation to confirm the maximum calculated short circuit current available under faulted conditions did not exceed the equipment rating and the protective fuses were adequately sized to isolate the fault and protect the affected equipment. In addition, the inspectors reviewed voltage drop calculations to verify the minimum voltage available at the equipment for the duration of the duty cycle was sufficient to ensure the proper operation of equipment under limiting operating and environmental conditions. The review included verification that the battery tests conformed to the design and TS requirements, enveloped the calculated load profile for the duration of the duty cycle, confirmed the battery capacity exceeded the minimum capacity required under limiting conditions, and that they were capable of detecting battery degradation. The inspectors reviewed battery charger sizing calculations to verify the chargers were capable of carrying the continuous load after a design basis accident and would be able to recharge the batteries to full capacity within the specified period. Additionally, the inspectors reviewed battery chargers tests to verify their capability of performing their intended function under design condition before their scheduled replacement.

Lastly, the inspectors reviewed the calculation and actions to conserve battery energy in the event of an SBO extended beyond the calculated coping period.

• Essential 125/250Vdc Distribution Panel (D2P): The inspectors reviewed the design and operation of the battery bus and associated DC distribution panel to verify the bus loading was within the design rating of the equipment and the individual components could perform their intended design function under worst case conditions. The inspectors also verified the equipment rating exceeded the maximum calculated short circuit faults. Additionally, the inspectors reviewed protective coordination studies to confirm selective coordination existed between supply and load fuses, such that equipment was adequately protected and faulted conditions were isolated without unnecessary loss of equipment.

b. Findings

No findings or violations of significance were identified; however, the inspectors identified one unresolved item as described below.

(1) Impact of a High Energy Line Break in the Turbine Building on Safety-Related Electrical Equipment Located in the Switchgear Rooms

Introduction:

The inspectors identified an unresolved item related to the design features to protect the low and high voltage switchgear rooms, including the battery rooms, from the temperature and humidity effects of a high energy line break (HELB) in the turbine building. Specifically, the licensee relied on non-safety-related equipment that may not function under a HELB scenario.

Description:

The non-safety-related non-radwaste area ventilation system provides ventilation for the low and high voltage switchgear rooms, as well as the battery rooms.

The ventilation supply fan takes suction from a mixing box supplied from turbine building, recirculation flow from the switchgear rooms, and outside air sources. A temperature controller modulates dampers on the three air supplies to ensure an appropriate mix of air in the mixing box.

The licensee credited the non-safety-related ventilation system in mitigating the consequences of the event since commercial operation. In 2010 as documented in CR-2010-080802, the licensee identified that a turbine building HELB would close the fire damper associated with the safety-related ventilation system fan such that the ventilation system would not be able to exhaust into the turbine building to cool the switchgear room. In evaluating this issue, the licensee credited the proper operation of the non-safety ventilation system controls, as well as the non-safety fan and its modulating dampers even though the equipment was not designed or qualified to operate under a HELB scenario. The licensee reasoned that since the controls of the non-safety-related system were not exposed to a harsh environment, the system could be credited for mitigating the consequences of a turbine building HELB.

The inspectors disagreed with the licensees assessment and were concerned a HELB in the turbine building may result in a hot, moist environment entering into the switchgear room through the two non-radwaste area ventilation system dampers (exhaust and supply) and the safety-related switchgear ventilation system damper located in the turbine building. The non-safety-related modulating damper located in the turbine building supply air duct, which the licensee relied upon for mitigation of a turbine building HELB were qualified for pressure rating of 6 inches of water while the plants HELB analysis showed a peak pressure of 1.06 psig (~30 inches of water). As such, the peak pressure may damage the modulating dampers and the isolation damper preventing their closure based on their lower design operating pressure. Furthermore, depending on the size and location of the break, the temperature of the HELB air entering the switchgear rooms may be lower than 135ºF setpoint to close the non-safety-related isolation damper on high temperatures and shut off the operating fan. As a result, these scenarios could prevent the isolation of the switchgear rooms from the turbine building HELB environment.

The non-safety-related temperature controller TC-5325, controlling the movements of the modulating dampers for temperature control, was calibrated on February 1, 2012, and found to be out of calibration. The desired output was 8.0 psig with a 0.2 psi tolerance, but the controller was found with a 1.07 psi error. The error would allow more air from the turbine building and less air from the outside entering the switchgear rooms.

The result of such error could aggravate the consequences of a turbine building HELB on components located in the switchgear rooms because at range of certain flow rate of steam into the switchgear rooms, the modulating damper could allow greater flow of steam from the turbine building into the switchgear rooms.

A review of design specification M-324AQ, Technical Specification for Operational Phase Miscellaneous Electronic Controls, showed the maximum relative humidity for some of the safety-related switchgear equipment located in the low voltage switchgear Room 2 was 90 percent (without condensation). A review of specification E-7Q, Technical Specification for Operational Phase for 480V Unit Substations, and E-8Q, Technical Specification for Operational Phase for AC and DC Motor Control Centers, showed the equipment purchased would be located at a high humidity site and relevant other electrical specifications have a value of 60-85 percent relative humidity associated with the term high humidity site. All remaining electrical equipment in the switchgear rooms was qualified to 100 percent relative humidity, but without condensation. This was a concern because if the temperature of the humid HELB air was greater than the initial temperature of the switchgear room (could be as low as 60ºF), the high humidity from the HELB would condense on the sensitive switchgear electrical equipment. This could result in the failure of the sensitive switchgear equipment and consequently in the failure of the electrical distribution system to numerous safety-related components.

The licensee initiated CR-2012-12292 and performed a prompt operability determination and also issued Standing Order 2012-011 to caution the operators and instruct them to immediately isolate a steam line break, regardless of the size. The inspectors had several concerns with this evaluation. Specifically, the licensee relied on the operation of installed ventilation duct fire dampers, however, these dampers did not provide a reasonable assurance of operability because

(a) the dampers have not been actuated since their installation 37 years ago;

(b) the temperature of the air entering the room may not be high enough (165ºF to 176ºF) to actuate them; and

(c) the dampers design pressure was much lower than the pressure expected during a HELB (as low as 0.25 inches of water). In addition, the licensees prompt operability determination credited operator action to isolate the steam break within 3 minutes of the break versus the 10 minutes assumed by the procedure. Moreover, the prompt operability determination did not take into account the possibility of a single failure (e.g., MSIV fails to close), which was described in USAR Section 3.6.2.7.1.16, Environmental Effects Due to HELB in the Turbine Building, as the worst case resulting in the highest mass and energy release into the turbine building and the largest pressure and temperature excursion into the adjoining switchgear rooms.

Based on the inspectors concerns with the reliance on equipment that may not function under a turbine building HELB scenario, the licensee implemented ECP 2012-0632 to modify the plant design by permanently closing exhaust damper CV5325B, supply damper CV5325C, and fire doors 519A and 520A. This design change would allow the non-safety-related non-radwaste area ventilation system to function by taking suction from outside air combined with recirculated air from the switchgear rooms. The change would also protect the switchgear rooms from the consequences of a HELB in the turbine building.

The inspectors were concerned with two different turbine building HELB scenarios that could affect the safety-related switchgear rooms. The first concern was a large HELB, such as a main steam line break, where the turbine peak pressure would exceed the pressure ratings on the ventilation dampers such that the dampers may not function to isolate the HELB from the switchgear room. The second concern was a smaller HELB that would allow the non-radwaste ventilation system to function as designed, which during winter operation may continue to allow the hot/humid environment to enter the switchgear rooms in order to maintain the ventilation system set point temperature of 70ºF. The inspectors received additional information on the operation of the ventilation control equipment, specifically the smoke detectors, that need to be evaluated.

Based on the inspectors concerns, the licensee was performing some additional analysis. Since this analysis was not completed prior to the end of the inspection, this issue is considered an unresolved item (URI 05000346/2012008-01) pending the following actions: 1) NRC review of whether the non-safety ventilation system would have functioned as necessary during a smaller HELB in the turbine building; 2) licensee determining which turbine building pipe breaks could produce a peak pressure that would exceed the ratings of the non-safety ventilation system dampers; and 3) an analysis that would determine the effects of a large turbine building HELB on the non-safety ventilation system and the resultant effects on the safety-related equipment in the switchgear rooms.

.4 Operating Experience

a. Inspection Scope

The inspectors reviewed six operating experience issues to ensure that NRC generic concerns had been adequately evaluated and addressed by the licensee. The operating experience issues listed below were reviewed as part of this inspection:

• Bulletin 85-01, Steam Binding of Auxiliary Feedwater Pumps;

• IN 1988-43, Solenoid Valve Problems;

• IN 2006-22, New Ultra-Low-Sulfur Diesel Fuel Oil Could Adversely Impact Diesel Engine Performance;

• IN 2009-10, Transformer Failures-Recent Operating Experience; and

• IN 2010-26, Submerged Safety-Related Electrical Cables; and

• NERC Reliability Standard NUC-01-02, Nuclear Plant Interface Coordination.

b. Findings

No findings of significance were identified.

.5 Modifications

a. Inspection Scope

The inspectors reviewed three permanent plant modifications related to selected risk significant components to verify the design bases, licensing bases, and performance capability of the components had not been degraded through modifications. The modifications listed below were reviewed as part of this inspection effort:

• ECP 07-0049-00, Replacement of SBODG Radiator Fan;

• ECR 05-0255-00, Separate Power Supplies for the Main Transformer Cooling Fans; and

• ECP 11-0512-000, YAU and YBU Circuits Moved to YAR and YBR.

b. Findings

No findings of significance were identified.

.6 Operating Procedure Accident Scenarios

a. Inspection Scope

The inspectors performed a detailed review of the procedures listed below associated with the Station Blackout scenario. The time significant, beyond design basis operator actions described were reviewed for effectiveness, in-plant actions were validated with operators, and interfaces with other departments were reviewed. The procedures and associated actions were also compared to the USAR, design assumptions, and training materials for consistency. In addition, significant, beyond design basis operator actions were observed during the performance of the Station Blackout scenario on the station simulator.

The following operating procedures and associated significant operator actions were reviewed in detail:

• DB-OP-02546, Degraded Grid;

• DB-OP-02000, RPS, SFAS, SFRCS Trip, or SG Tube Rupture;

• DB-OP-02521, Loss of AC Bus Power Sources;

• DB-OP-06334, Station Blackout Diesel Generator Operating Procedure; and

• DB-OP-02600, Operational Contingency Response Action Plan.

b. Findings

No findings of significance were identified.

4OA2 Identification and Resolution of Problems

.1 Review of Items Entered Into the Corrective Action Program

a. Inspection Scope

The inspectors reviewed a sample of the selected component problems that were identified by the licensee and entered into the corrective action program. The inspectors reviewed these issues to verify an appropriate threshold for identifying issues and to evaluate the effectiveness of corrective actions related to design issues. 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 inspectors are listed in the Attachment to this report.

The inspectors also selected four issues that were identified during previous CDBIs to verify the concern was adequately evaluated and corrective actions were identified and implemented to resolve the concern, as necessary. The following issues were reviewed:

• NCV 05000346/2007007-02, Periodic Testing of 480V Starter Coils not Implemented;

• NCV 05000346/2009007-05, Inadequate Procedure for a Loss of Coolant Accident Outside Containment;

• NCV 05000346/2007007-01, Inadequate Battery Voltage Drop and Sizing Design Calculation; and

• CR 09-68063, DC Aux Lube Oil Pump For Make-Up Pump.

b. Findings

No findings of significance were identified.

4OA6 Meetings

.1 Exit Meeting Summary

On November 2, 2012, the inspectors presented the inspection results to Mr. R. Lies, and other members of the licensee staff. The licensee acknowledged the issues presented.

.2 Interim Exit Meeting Summary

On September 14, 2012, the inspectors presented the preliminary inspection results to Mr. B. Allen, and other members of the licensee staff. The licensee acknowledged the issues presented. The inspectors asked the licensee whether any materials examined during the inspection should be considered proprietary. Several documents reviewed by the inspectors were considered proprietary information and were either returned to the licensee or handled in accordance with NRC policy on proprietary information.

ATTACHMENT:

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee

R. Lieb, Site Vice President (current)

B. Allen, Site Vice President (previous)

D. Andrews, PRA Analyst

E. Bennett, Plant Engineering

K. Betker, Plant Engineering

D. Blakely, Supervisor, Design Engineering

C. Bleau, Design Engineering

A. Bless, Electrical Design Engineering

K. Byrd, Director, Site Engineering

J. Dominy, Director, Site Maintenance

T. Henline, Supervisor, Technical Services

J. Hook, Manager, Design Engineering

D. Imlay, Director, Site Performance Improvement

T. Laurer, Plant Electrical Engineer

B. Kremer, Manager, Plant Engineering

P. McCloskey, Manager, Site Regulatory Compliance

A. Quaderer, PRA Analyst

K. Slauterbeck, Nuclear Engineer

T. Stallard, Superintendent, Nuclear Operations

T. Summers, Manager, Site Operations

V. Wadsworth, Sr. Nuclear Specialist, Regulatory Compliance

A. Wise, Manager, Technical Services

G. Wolf, Supervisor, Regulatory Compliance

B. Young, Supervisor, Plant Engineering

K. Zellers, Supervisor, Reactor Engineering

F. Zurvalec, Technical Services

Nuclear Regulatory Commission

D. Kimble, Senior Resident Inspector

A. Wilson, Resident Inspector

LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED

Opened

05000346/2012008-01 URI Impact of a High Energy Line Break in the Turbine Building on Safety-Related Electrical Equipment Located in the Switchgear Rooms (Section 1R21.3.b.(1))

Closed and

Discussed

None Attachment