IR 05000352/2008003

IR 05000352-08-003 & 05000353-08-003; on 04/01/2008 - 06/30/2008; Limerick Generating Station, Units 1 and 2; Problem Identification and Resolution

ML082261341
Person / Time
Site:	Limerick
Issue date:	08/13/2008
From:	Paul Krohn Reactor Projects Region 1 Branch 4
To:	Pardee C AmerGen Energy Co, Exelon Generation Co
KROHN P, RI/DRP/PB4/610-337-5120
References
IR-08-003
Download: ML082261341 (29)

Text

ust 13, 2008

SUBJECT:

LIMERICK GENERATING STATION - NRC INTEGRATED INSPECTION REPORT 05000352/2008003 AND 05000353/2008003

Dear Mr. Pardee:

On June 30, 2008, the U. S. Nuclear Regulatory Commission (NRC) completed an inspection at your Limerick Generating Station Units 1 and 2. The enclosed integrated inspection report documents the inspection results which were discussed on July 7, 2008, with Mr. C. Mudrick 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.

This report documents one NRC-identified finding of very low safety significance (Green).

The finding was determined to involve a violation of an NRC requirement. Additionally, two licensee-identified violations which were determined to be of very low safety significance are listed in this report. However, because of the very low safety significance and because they are entered into your corrective action program (CAP), the NRC is treating these findings as non-cited violations (NCVs), consistent with Section VI.A.1. of the NRC Enforcement Policy.

If you contest any NCV in this report, you should provide a response within 30 days of the date of this inspection report, with basis for your denial, to the Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administration, Region 1; the Director, Office of Enforcement, United States Nuclear Regulatory Commission, Washington, DC 20555-001; and the NRC Resident Inspector at the Limerick facility.

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 (PARS) component of the NRCs document system (ADAMS). ADAMS is accessible from the NRC Website at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/RA/

Paul G. Krohn, Chief Projects Branch 4 Division of Reactor Projects Docket Nos: 50-352, 50-353 License Nos: NPF-39, NPF-85 Enclosure: Inspection Report 05000352/2008003 and 05000353/2008003 w/Attachment: Supplemental Information cc w/encl:

C. Crane, Executive Vice President and Chief Operating Officer, Exelon Generation M. Pacilio, Chief Operating Officer, Exelon Generation Company, LLC C. Mudrick, Site Vice President - Limerick Generating Station E. Callan, Plant Manager, Limerick Generating Station R. Kreider, Regulatory Assurance Manager R. DeGregorio, Senior Vice President, Mid-Atlantic Operations K. Jury, Vice President, Licensing and Regulatory Affairs P. Cowan, Director, Licensing D. Helker, Licensing B. Fewell, Associate General Counsel Correspondence Control Desk D. Allard, Director, PA Department of Environmental Protection J. Johnsrud, National Energy Committee, Sierra Club Chairman, Board of Supervisors of Limerick Township J. Powers, Director, PA Office of Homeland Security R. French, Director, PA Emergency Management Agency

SUMMARY OF FINDINGS

IR 05000352/2008003, 05000353/2008003; 04/01/2008 - 06/30/2008; Limerick Generating

Station, Units 1 and 2; Problem Identification and Resolution.

The report covered a three-month period of inspection by resident inspectors and an announced inspection by a regional health physics inspector. One NRC-identified Green finding, determined to be a non-cited violation (NCV), was identified. The significance of most findings is indicated by their color (Green, White, Yellow, Red) using Inspection Manual Chapter (IMC)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 NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight," Revision 4, dated December 2006.

Cornerstone: Barrier Integrity

Green.

The inspectors identified an NCV of Title 10 of the Code of Federal Regulations, Part 50 (10CFR50), Appendix B, Criterion XVI, Corrective Action, for not correcting a condition adverse to quality associated with safety-related motor operated valve motor control center auxiliary contact switches in a timely manner following the failure of the Unit 1 Core Spray Loop A test bypass primary containment isolation valve (HV-052-1F015A) to close on August 3, 2006. As a result, the Unit 2 Reactor Core Isolation Cooling (RCIC) turbine exhaust line vacuum breaker outboard primary containment isolation valve (HV-049-2F080) experienced a similar failure to close on June 4, 2008.

The finding was more than minor because it was associated with the structures, systems, and components and barrier containment performance attribute of the Barrier Integrity cornerstone and affected the objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents and events. The inspector assessed the finding using Phase 1 of IMC 0609, Appendix A, Significance Determination Process for Reactor Inspection Findings for At-Power Situations and determined the finding to be of very low safety significance (Green) because the finding did not represent an actual open pathway in the physical integrity of reactor containment. This finding has a cross-cutting aspect of Problem Identification and Resolution because Exelon did not take appropriate corrective actions to address safety issues and adverse trends in a timely manner, commensurate with the safety significance and complexity (P.1(d)).

(Section 4OA2)

Licensee-Identified Violations

Violations of very low safety significance, which were identified by Exelon, have been reviewed by the inspectors. Corrective actions taken or planned by Exelon have been entered into their corrective action program. These violations and corrective actions are listed in Section 4OA7 of this report.

REPORT DETAILS

Summary of Plant Status

Unit 1 began the inspection period operating at full rated thermal power (RTP). On April 5, 2008, operators reduced power to approximately 85 percent to facilitate a control rod pattern adjustment and to return control rod hydraulic control units to service following maintenance.

Full RTP was achieved on April 6, 2008. A planned downpower to approximately 77 percent was performed on May 16, 2008, to facilitate control rod scram time testing, main turbine valve testing, and secondary plant maintenance. Full RTP was achieved on May 17, 2008. Unit 1 operated at full RTP for the remainder of the inspection period.

Unit 2 began the inspection period operating at full RTP. On April 26, 2008, operators reduced power to approximately 25 percent to facilitate main steam isolation and main turbine valve testing, control rod scram time testing, and to perform hot weather readiness preventive maintenance. Full RTP was achieved on April 27, 2008. On May 22, 2008, operators reduced power to approximately 60 percent to facilitate main turbine valve testing and to perform secondary plant maintenance. Power was restored to full RTP on May 23, 2008. Unit 2 operated at full RTP for the remainder of the inspection period.

REACTOR SAFETY

Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity

1R01 Adverse Weather Protection

.1 Summer Readiness of Offsite and Alternate Alternating Current (AC) Power Systems

a. Inspection Scope

The inspectors performed a review of plant features and procedures for the operation and continued availability of the offsite and alternate AC power system to evaluate the readiness of the systems prior to seasonal high grid loading. The inspectors reviewed Exelons procedures affecting these areas and the communications protocols between the transmission system operator and Exelon. This review focused on verifying that appropriate information is exchanged when grid conditions arise that could impact the offsite power system. The inspector assessed whether appropriate procedures and protocols were established and implemented to monitor and maintain availability and reliability of both the offsite AC power system and the onsite alternate AC power system.

Documents reviewed are listed in the Attachment.

b. Findings

No findings of significance were identified.

.2 External Flooding

a. Inspection Scope

The inspectors performed a review of external flood protection barriers associated with the Emergency Diesel Generator (EDG) fuel oil storage tanks and the safety-related service water underground manholes. The inspectors reviewed the Updated Final Safety Analysis Report (UFSAR) to identify design features for coping with external flooding. The inspectors performed a walkdown of accessible fuel oil storage tank vaults and underground manholes associated with the service water system to verify that design features for the protection of water intrusion were installed and functional. The inspector reviewed preventive maintenance and site procedures to verify that commitments associated with the protection of water intrusion for the areas were properly established. Documents reviewed are listed in the Attachment.

b. Findings

No findings of significance were identified.

1R04 Equipment Alignment

Partial Walkdown (71111.04Q - 3 samples)

a. Inspection Scope

The inspectors performed a partial walkdown of the plant systems listed below to verify the operability of redundant or diverse trains and components when safety-related equipment in the opposite train was either inoperable, undergoing surveillance testing, or potentially degraded. The inspectors used plant Technical Specifications (TS), Exelon operating procedures, plant piping and instrumentation drawings (P&IDs), and the USFAR as guidance for conducting partial system walkdowns. The inspectors reviewed the alignment of system valves and electrical breakers to ensure proper in-service or standby configurations as described in plant procedures and drawings. During the walkdown, the inspectors evaluated material condition and general housekeeping of the system and adjacent spaces. The documents reviewed are listed in the Attachment.

The inspectors performed walkdowns of the following areas:

• A Control Room Emergency Fresh Air System (CREFAS) with B CREFAS out-of-service for planned maintenance;

• D22 EDG following return-to-service due to fuel oil storage tank inspection; and

• 2 A and C Residual Heat Removal (RHR) pumps with 2 D RHR pump out of service for planned maintenance.

b. Findings

No findings of significance were identified.

1R05 Fire Protection

Fire Protection - Tours (71111.05Q - 5 samples)

a. Inspection Scope

The inspectors conducted a tour of the five areas listed below to assess the material condition and operational status of fire protection features. The inspectors verified that combustibles and ignition sources were controlled in accordance with Exelons administrative procedures, fire detection, and suppression equipment was available for use, and that passive fire barriers were maintained in good material condition. The inspectors also verified that station personnel implemented compensatory measures for out-of-service, degraded, or inoperable fire protection equipment in accordance with the stations fire plan. The documents reviewed are listed in the Attachment. The inspectors toured the following areas:

• Spray Pond Pumphouse;

• Auxiliary Equipment Room and Remote Shutdown Panel Room;

• Diesel-Driven Fire Pump Room;

• D22 EDG Fuel Oil Storage Tank (FOST) Vault; and

• D21 EDG and Fuel Oil/Lube Oil Tank Room.

b. Findings

No findings of significance were identified.

1R06 Flood Protection Measures

a. Inspection Scope

The inspectors reviewed the UFSAR and related flood analysis document to identify areas that can be affected by internal flooding, to identify features designed to alert operators of a flooding event, and to identify features designed for coping with internal flooding. The inspectors performed a walkdown of Units 1 and 2 Emergency Core Cooling Pump Rooms (Reactor Buildings, Elevation 177). The inspectors observed flood protection features to assess their ability to minimize the impact of a flooding event.

The inspector verified that periodic preventive maintenance was established for flood detection equipment in these areas. The inspector performed a review of operator actions contained in off-normal procedures for flooding to verify that they can reasonably be used to achieve desired actions. Documents reviewed are listed in the Attachment.

b. Findings

No findings of significance were identified.

1R11 Licensed Operator Requalification Program

a. Inspection Scope

On April 29, 2008, the inspectors evaluated licensed operator requalification simulator scenarios on two operating crews. The scenario tested the operators ability to respond to various failures, including the loss of power to plant equipment, control rod malfunctions, a fuel failure, and a steam leak outside containment. The inspectors observed licensed operator performance including operator critical tasks that measure operator actions required to ensure the safe operation of the reactor and protection of the nuclear fuel and primary containment barriers. The inspectors also assessed group dynamics and supervisory oversight to verify the ability of operators to properly identify and implement appropriate TS actions, regulatory reports, and notifications. The inspectors observed and reviewed the training evaluators grading and critiques and assessed whether appropriate feedback was provided to the licensed operators. The documents reviewed are listed in the Attachment.

b. Findings

No findings of significance were identified.

1R12 Maintenance Effectiveness

a. Inspection Scope

The inspectors evaluated Exelons work practices and follow-up corrective actions for structures, systems, and components (SSCs) and identified issues to assess the effectiveness of Exelons maintenance activities. The inspectors reviewed the performance history of risk significant SSCs and assessed Exelons extent-of-condition determinations for those issues with potential common cause or generic implications to evaluate the adequacy of the stations corrective actions. The inspectors assessed Exelons problem identification and resolution actions for these issues to evaluate whether Exelon had appropriately monitored, evaluated, and dispositioned the issues in accordance with Exelon procedures and the requirements of 10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance. In addition, the inspectors reviewed selected SSC classifications, performance criteria and goals, and Exelons corrective actions that were taken or planned, to evaluate whether the actions were reasonable and appropriate. The documents reviewed are listed in the

. The inspectors performed the following samples:

• Issue Report (IR) 707564, Maintenance Rule a(1) Determination for Instrument Air System; and

• IR 671975, HV-055-2F093 Failed to Operate from Handswitch.

b. Findings

No findings of significance were identified.

1R13 Maintenance Risk Assessments and Emergent Work Control

a. Inspection Scope

The inspectors evaluated the effectiveness of Exelons maintenance risk assessments required by 10 CFR 50.65(a)(4). This inspection included discussion with control room operators and risk analysis personnel regarding the use of Exelons on-line risk monitoring software. The inspectors reviewed equipment tracking documentation, daily work schedules, and performed plant tours to gain assurance that the actual plant configuration matched the assessed configuration. Additionally, the inspectors verified that Exelons risk management actions, for both planned and emergent work, were consistent with those described in Exelon procedure, ER-AA-600-1042, On-Line Risk Management. The documents reviewed are listed in the Attachment. Inspectors reviewed the following samples:

• Unit 2 RHR Heat Exchanger Repairs with a Control Rod Drive Pump Out-of-Service during Work Week 0815;

• IR 762240, Unit 2 A RHR Heat Exchanger Bypass Valve Failure (HV-C-051-2F048A);

• IR 737066, Unit 2 Main Turbine Valve Testing following Abnormal Bypass Valve Response;

• Emergent Work on Reactor Enclosure Recirculation System (RERS) during B CREFAS Out of Service for Planned Maintenance;

• Emergent Work on A CREFAS during Unit 1 A Core Spray (CS) System Outage Window (SOW), D22 EDG FOST Cleaning, and D11 EDG SOW; and

• IR 790935, Emergent Work on D14 EDG due to Load and Voltage Transient during Post-Maintenance Testing.

b. Findings

No findings of significance were identified.

1R15 Operability Evaluations

a. Inspection Scope

For the five operability evaluations described below, the inspectors assessed the technical adequacy of the evaluations to ensure that Exelon properly justified TS operability and verified that the subject component or system remained available such that no unrecognized increase in risk occurred. The inspectors reviewed the UFSAR to verify that the system or component remained available to perform its intended safety function. In addition, the inspectors reviewed compensatory measures implemented to ensure that the measures worked and were adequately controlled. The inspectors also reviewed a sample of issue reports to verify that Exelon identified and corrected deficiencies associated with operability evaluations. The documents reviewed are listed in the Attachment. The inspectors performed the following assessments:

• IR 756914, Unit 1C Safety/Relief Valve Second Stage Temperature is Reading Two Degrees Low;

• IR 765052, D12 FOST Mechanical Indictor Stuck;

• IR 766331, Unit 2A Suppression Pool Cooling Return Valve (HV-051-2F024A) Stem-to-Disc Separation;

• IR 758875, D23 EDG Jacket Water and Lubricating Oil Temperature Switches Found Out-of-Calibration; and

• IR 780592, A Flow Balance 89-13 Margin Review of CS Unit Coolers.

b. Findings

No findings of significance were identified.

1R19 Post-Maintenance Testing

a. Inspection Scope

The inspectors reviewed the seven post-maintenance tests (PMTs) listed below to verify that procedures and test activities ensured system operability and functional capability.

The inspectors reviewed Exelons test procedures to verify that the procedures adequately tested the safety functions that may have been affected by the maintenance activity, and that the acceptance criteria in the procedures were consistent with information in the licensing and design basis documents. The inspectors also witnessed the test or reviewed test data to verify that the results adequately demonstrated restoration of the affected safety functions. The documents reviewed are listed in the

. The inspectors performed the following samples:

• C0224662, Unit 2A RHR Heat Exchanger Bypass Valve (HV-C-051-2F048A)

Repairs;

• C0223007, Unit 2A RHR Suppression Pool Cooling Return Valve (HV-051-F024A)

Repairs;

• ST-6-076-250-1 following Unit 1A RERS SOW;

• R1096864, Overhaul Unit 1 Control Rod Drive Hydraulic Control Unit 26-03 Waterside Components;

• ST-6-076-250-2, Standby Gas Treatment System (SGTS) and RERS Flow Test following 2B RERS SOW;

• High Pressure Coolant Injection (HPCI) Valve Test and Pump, Valve and Flow Test following Unit 1 HPCI SOW; and

• C0225543, D14 EDG Troubleshooting and Repairs following Load Transient during Testing.

b. Findings

No findings of significance were identified.

1R22 Surveillance Testing

a. Inspection Scope

The inspectors witnessed the performance and reviewed test data for five surveillance tests (STs) that are associated with risk-significant SSCs. The review verified that Exelon personnel followed TS requirements and that acceptance criteria were appropriate. The inspectors also verified that the station established proper test conditions, as specified in the procedures, that no equipment preconditioning activities occurred, and that acceptance criteria had been met. The documents reviewed are listed in the Attachment. The inspectors reviewed STs for the following systems and components:

• ST-6-092-315-2, D21 Diesel Generator Fast Start Operability Test Run;

• ST-6-092-316-1, D12 Diesel Generator Fast Start Operability Test Run;

• ST-6-092-115-1, D11 Diesel Generator Loss of Coolant Accident /Loss of Coolant Projection Test;

• ST-6-049-230-1, RCIC Pump, Valve, and Flow Test; and

• ST-6-076-250-1, SBGT and RERS Flow Test.

b. Findings

No findings of significance were identified.

EP6 Drill Evaluation

a. Inspection Scope

The inspectors observed the training evolution and emergency preparedness drills listed below to assess Exelons emergency response organizations (ERO) implementation of the Limerick emergency plan and implementing procedures. The inspectors reviewed EROs response to simulated degraded plant conditions to identify weaknesses and deficiencies in classification, notification, and PAR development activities. In addition, the inspectors assessed licensed operator performance required to ensure the safe operation of the reactor and the protection of the nuclear fuel and primary containment barriers. The inspectors observed Exelons controller and evaluators critiques of the drill to evaluate Exelons identification of weaknesses and deficiencies. The inspectors compared inspector observed weaknesses with those identified in Exelons drill critique to verify whether Exelon adequately identified weaknesses and deficiencies at an appropriate threshold. The inspector verified that the licensee appropriately assessed ERO performance with regard to activities contributing to the Drill and Exercise Performance (DEP) performance indicator training evolution and drills. The documents reviewed are listed in the Attachment. The inspectors assessed the following samples:

• Simulator Training Exercise conducted on April 29, 2008;

• Emergency Preparedness Drill conducted on June 3, 2009; and

• Emergency Preparedness Drill conducted on June 18, 2008.

b. Findings

No findings of significance were identified.

RADIATION SAFETY

Cornerstone: Public Radiation Safety

2PS2 Radioactive Material Processing and Transportation (71122.02 - 6 samples)

a. Inspection Scope

During the period June 2 - 6, 2008, the inspector conducted the following activities to verify that Exelons radioactive material processing and transportation programs complied with the requirements of 10 CFR 20, 61, 71, and Department of Transportation (DOT) regulations 49 CFR 170-189. The documents reviewed are listed in the

.

Radioactive Waste Systems Walkdown The inspector walked down accessible portions of the radioactive liquid processing systems and site radwaste storage areas with the Radwaste Systems Engineer and a Radiation Protection Specialist, respectively. During the tour, the inspector evaluated if the systems and facilities were consistent with the descriptions contained in the UFSAR and the Process Control Program (PCP), evaluated the general material conditions of the systems and facilities, and identified any changes to the systems. The inspector reviewed the current processes for transferring radioactive resin/sludge to shipping containers, and the subsequent de-watering process.

Also during this tour, the inspector walked down portions of radwaste systems that are no longer in service or abandoned in place, and discussed the status of administrative and physical controls for these systems including components of the radwaste evaporators and centrifuges.

The inspector visually inspected various radioactive material storage locations with the Radiation Protection Specialist, including areas of the Radwaste Building, outside yard locations within the Protected Area, and the on-site disposal site (10 CFR 20.2002 area)to evaluate material conditions.

Waste Characterization and Classification The inspection included a selective review of the waste characterization and classification program for regulatory compliance, including:

The radio-chemical sample analytical results for various radioactive waste streams; The development of scaling factors for hard-to-detect radio-nuclides from radio-chemical data; The methods and practices to detect changes in waste streams; and The characterization and classification of waste relative to 10 CFR 61.55 and the determination of DOT shipment subtype per 49 CFR 173.

Shipment Preparation The inspection included a review of radioactive waste program records, shipment preparation procedures, training records, and observations of jobs-in-progress, including:

• Reviewing radwaste and radioactive material shipping logs for calendar years 2006, 2007, and 2008;

• Verifying that training was provided to appropriate personnel responsible for classifying, handling, and shipping radioactive materials, in accordance with Bulletin 79-19 and 49 CFR 172 Subpart H;

• Verifying that appropriate NRC (or agreement state) license authorization was current for shipment recipients for recent shipments;

• Observing a radwaste Shipping Supervisor provide briefing instructions to a driver for shipment MW-08-024; and

• Verifying compliance with the relevant Certificates-of-Compliance and related procedures for shipping casks.

Shipment Records The inspector selected and reviewed records associated with five Type B shipments of radioactive material made since the last inspection of this area. The shipment numbers were MW-07-014, MW-07-015, MW-07-016, MW-07-017, and MW-07-018. The inspector reviewed the following aspects of the radioactive waste packaging and shipping activities:

• Implementation of applicable shipping requirements including proper completion of manifests;

• Implementation of specifications in applicable certificates-of-compliance, for the approved shipping casks, including limits on package contents;

• Verification that dewatering criteria was met;

• Classification of radioactive materials relative to 10 CFR 61.55 and 49 CFR 173;

• Labeling of containers relative to package dose rates;

• Radiation and contamination surveys of the packages;

• Placarding of transport vehicles;

• Conduct of vehicle checks;

• Providing of emergency instructions to the driver;

• Completion of shipping papers; and

• Notification by the recipient that the radioactive materials have been received and disposed of.

Identification and Resolution of Problems The inspector reviewed the 2007 Annual Radioactive Effluent Release Report, relevant Issue Reports, a Nuclear Oversight Audit, a self-assessment report and recent Yard Area Rad Material Inspection reports. Through this review, the inspector assessed Exelons threshold for identifying problems, and the promptness and effectiveness of the resulting corrective actions. This review was conducted against the criteria contained in 10 CFR 20.1101(c) and Exelons procedures.

b. Findings

No findings of significance were identified.

4OA1 Performance Indicator (PI) Verification

a. Inspection Scope

The inspectors sampled Exelons submittal of the initiating events and mitigating systems performance indicators listed below to verify the accuracy of the data recorded from the fourth quarter of 2007 through the first quarter of 2008. The inspectors utilized performance indicator definitions and guidance contained in Nuclear Energy Institute (NEI) 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 5, to verify the basis in reporting for each data element. The inspectors reviewed various documents, including portions of the main control room logs, issue reports, power history curves, work orders, and system derivation reports. The inspectors also discussed the method for compiling and reporting performance indicators with cognizant engineering personnel and compared graphical representations from the most recent PI report to the raw data to verify that the report correctly reflected the data. The documents reviewed are listed in the Attachment.

Cornerstone: Mitigating Systems (6 samples)

• Units 1 and 2 Mitigating Systems Performance Index, Emergency AC Power System

• Units 1 and 2 Mitigating Systems Performance Index, Heat Removal System

• Units 1 and 2 Safety System Functional Failures

b. Findings

No findings of significance were identified.

4OA2 Identification and Resolution of Problems (71152 - 2 Annual Samples; 1 Semi-Annual

Trend Review)

.1 Review of Items Entered into the Corrective Action Program (CAP)

As required by Inspection Procedure 71152, Identification and Resolution of Problems, and in order to help identify repetitive equipment failures or specific human performance issues for follow-up, the inspectors screened all items entered into Limericks corrective action program. The inspectors accomplished this by reviewing each new condition report, attending management review committee meetings, and accessing Exelons computerized database.

.2 Semi-Annual Review to Identify Trends

a. Inspection Scope

As required by inspection procedure 71152, Identification and Resolution of Problems, the inspectors performed a review of Exelons CAP and associated documents to identify whether trends existed that would indicate a more significant safety issue. The review considered the period of January through June 2008 and was focused on repetitive equipment issues. The results of routine inspector CAP item screening, Exelons trending efforts, and human performance results were also considered. The inspectors reviewed issues documented outside the normal CAP such as Plant Health Committee reports including the Top Ten Equipment Issues List, the Plant Health Committee Issues List, and the Open Action Items List. The inspectors compared and contrasted their results with the results contained in the Limerick Generating Station Performance Trending reports for the first quarter 2008.

b. Assessment and Observations No findings of significance were identified. The review did not reveal any trends that could indicate a more significant safety issue. The inspectors assessed that Exelon was identifying issues at a low threshold and entering the issues into the CAP for resolution.

.3 Annual Sample: 2A RHR High Discharge Pressure Alarm

a. Inspection Scope

The inspectors reviewed Limericks corrective actions associated with IR 709219 regarding a 2A RHR pump discharge high pressure alarm. The inspectors reviewed system operating procedures, applicable motor-operated valve calculations, system drawings, operator logs, and design basis documents as well as other past issue reports to ensure Exelon took appropriate actions in accordance with the requirements of their corrective action program.

b. Findings and Observations

No findings of significance were identified. The inspectors confirmed that the high RHR pump discharge pressure would not adversely affect the operation of the RHR motor operated valves and therefore not affect the safety function of the system. Additionally, the inspectors confirmed that Exelon appropriately categorized and prioritized this issue in their corrective action program.

.4 Annual Sample: Unit 1 Core Spray Test Bypass Valve Failed to Close

a. Inspection Scope

The inspectors reviewed Limericks apparent cause evaluation, extent-of-condition, and corrective actions associated with IR 516425 regarding the failure of the Unit 1 CS test bypass primary containment isolation valve (PCIV) to close on August 2, 2006. The inspectors evaluated Exelons actions against the requirements of the corrective action program and applicable regulatory requirements.

b. Findings and Observations

Introduction.

The inspectors identified a Green, non-cited violation of 10CFR50, Appendix B, Criterion XVI, Corrective Action, for not correcting a condition adverse to quality associated with safety-related 480 volt motor operated valves (MOVs) in a timely manner.

Description.

On June 4, 2008, Unit 2 RCIC turbine exhaust line vacuum breaker outboard PCIV (HV-049-2F080) failed to close during testing. Exelon determined that the cause of the MOVs failure was mechanical binding due to misalignment between the auxiliary contact switches located in the associated motor control center starter. The contact switch arrangement was double stacked, meaning two sets of double auxiliary contacts switches (one base switch and one add-on switch) were connected on top of each other. Auxiliary contact switch binding due to misalignment between the base switch and add-on switch caused a normally closed set of contacts to stay in the open position. The contact serves as an interlock in the closing circuit for the valve to prevent simultaneous energization of the open and close coil in the control circuit. With the contact stuck in the open position, energization of the close coil was prevented.

The inspectors reviewed the history of MOV failures due to auxiliary contact switch binding. This review included IR 516425 associated with the failure of the Unit 1 CS Loop A test bypass PCIV (HV-052-1F015A) to close on August 3, 2006. Exelon also determined this failure to be caused due to binding of the double stacked auxiliary contact switches similar to the HV-049-2F080 failure. Exelons investigation found that the same failure mechanism had also been previously experienced at Peach Bottom Atomic Power Station. The problem associated with binding caused by misalignment of double stacked auxiliary contact switches was significantly reduced at Peach Bottom Atomic Power Station by eliminating the add-on double auxiliary contact switch and replacing them with less susceptible single auxiliary contact switches. Unused spare contacts were also eliminated which minimized the need to use more than one single auxiliary contact switch.

Exelon determined that the extent-of-condition of the cause of potential binding included all 480VAC motor starters installed with double stacked auxiliary contact switches on Units 1 and 2. For pumps and fans, the normally closed auxiliary contacts were typically used in non-critical indication circuits. However, for MOVs, the normally closed contact is used in the close and open interlock and failure will prevent valve operation. The stations corrective actions included inspecting all high and medium risk valve controllers, as defined by Exelons Specification NE-145, Selection of Generic Letter 96-05 Program Valves, to identify susceptible controllers and to develop a plan to eliminate the add-on double auxiliary contact arrangement during the next respective system outage window. No specific actions were identified for valves in low risk applications.

The corrective action for low risk valves was to develop a method to fully eliminate the use of this component in low risk applications. This action for low risk valves had a status note following it stating pending management decision on necessity. The due date for completing the corrective actions was June 30, 2009.

The inspectors compared the corrective actions associated with low risk valves with the guidance in LS-AA-125, Corrective Action Program Procedure, Revision 11. The inspectors concluded that these actions did not meet the guidance that corrective actions clearly state the desired end result or that the corrective actions address the identified cause.

The performance deficiency associated with this issue is the failure to take appropriate corrective actions in a timely manner to address the adverse condition of mechanical binding in double stacked auxiliary contact switches for low risk motor-operated valves.

The performance deficiency applies to both Units 1 and 2 because Exelons established corrective action in IR 516425 applied to both units. As a result, HV-049-2F080, a low risk safety-related valve, failed to close due to mechanical binding of the double stacked auxiliary contact switches on June 4, 2008. This performance deficiency applies to both Units 1 and 2 because Exelons established corrective actions in IR 516425 applied to both units.

Analysis.

The finding was more than minor because it was associated with the structures, systems, and components and barrier containment performance attribute of the Barrier Integrity cornerstone and affected the objective to provide reasonable assurance that physical design barriers protect the public from radionuclide releases caused by accidents and events. The inspector assessed the finding using Phase 1 of IMC 0609, Appendix A, Significance Determination Process for Reactor Inspection Findings for At-Power Situations and determined the finding to be of very low safety significance (Green) because the finding did not represent an actual open pathway in the physical integrity of reactor containment because the RCIC turbine exhaust line vacuum breaker inboard PCIV was available to be closed.

This finding has a cross-cutting aspect of Problem Identification and Resolution because Exelon did not take appropriate corrective actions to address safety issues and adverse trends in a timely manner, commensurate with the safety significance and complexity, in that, a previously identified deficiency, which disabled a primary containment isolation valve, was not corrected. This resulted in disabling an additional primary containment isolation valve. (P.1(d))

Enforcement.

10CFR50, Appendix B, Criterion XVI, Corrective Action, requires, in part, that measures shall be established to assure that conditions adverse to quality are promptly identified and corrected. Contrary to the above, between August 3, 2006 and June 4, 2008, Exelon did not correct a condition adverse to quality associated with safety-related motor operated valve motor control center auxiliary contact switches that was identified by the failure of Unit 1 CS Loop A test bypass PCIV (HV-052-1F015A) to close on August 3, 2006. Because the condition adverse to quality was not corrected, the Unit 2 RCIC turbine exhaust line vacuum breaker outboard PCIV (HV-049-2F080)did not close on June 4, 2008, due to binding of the auxiliary contact switch in its motor starter circuitry. Because the finding is of very low safety significance and has been entered into Exelons CAP as IR 781939, this violation is being treated as a Green NCV, consistent with Section VI.A.1 of the NRC Enforcement policy. This inspector-identified non-cited violation was entered into Exelons CAP as IR 781939. (NCV 05000352, 353/2008003-01, Failure to Correct Adverse Condition Associated with Motor Operated Valves.)

4OA3 Event Follow-Up

.1 Plant Event Review

a. Inspection Scope

For the two plant events listed below, the inspectors observed plant parameters and, as applicable, reviewed personnel performance and evaluated performance of mitigating systems. The inspectors communicated the plant events to appropriate regional personnel and compared the event details with criteria contained in IMC 0309, Reactive Inspection Decision Basis for Reactors, for consideration of additional reactive inspection activities. The inspectors reviewed Exelons follow-up actions related to the events to assure that appropriate corrective actions were implemented commensurate with their safety significance.

• IR 766331, Unit 2 A Suppression Pool Cooling Return Valve (HV-051-2F024A)

Discovered to Have a Stem-Disc Separation; and

• Unit 2 Turbine Building Condenser Bay Flooding due to Failure of a Circulating Water Anode on May 22, 2008.

b. Findings

No findings of significance were identified.

.2 (Closed) LER 05000352/02008-001: Source Range Monitor Inoperable While Control

Rod Moved.

On March 16, 2008, during the Unit 1 refueling outage, a control rod was withdrawn with the source range monitor in the affected core quadrant inoperable which is contrary to TS 3.9.2, Refueling Operations - Instrumentation. This issue was identified by an Instrumentation and Controls technician performing maintenance activities in the auxiliary instrument room. The root cause of the event was the control room supervisor and reactor operator failing to ensure the C source range monitor was not bypassed prior to declaring it operable. The source range monitor was restored to operable and the control rod was inserted. The event is documented in Exelons corrective action program as IR 750227. The enforcement aspects of this issue are discussed in Section 4OA7. This LER is closed.

.3 (Closed) LER 05000352/02008-002: Unit 1 Trip Due to Actuation of Power Load

Unbalance.

On March 22, 2008, Unit 1 automatically scrammed due to a main turbine trip during power escalation following refueling outage with the unit at 87 percent power. The root cause of the scram was the generator protection relay logic failure caused by an inadequately seated tap screw on the B phase of the Accidental Energization (350-G101) relay. The failure caused a false input into the power load unbalance circuit of the electro-hydraulic control system that resulted in a turbine trip and reactor scram.

Exelons investigation could not determine when the tap screw was inadequately seated.

The inspectors determined that there was no performance deficiency associated with this event since the post-maintenance testing performed following the relays replacement during the Spring 2008 refueling outage was consistent with industry practices. As a result of this event, the main generator relay testing procedures will be revised to include a circuit loop signal verification test to ensure reliability of newly installed equipment.

The event is documented in Exelons corrective action program as IR 750227. This LER is closed.

.4 (Closed) Licensee Event Report (LER) 05000353/02008-003: Condition Prohibited By

Technical Specifications Due To Inoperable Radiation Monitor.

On April 15, 2008, during a review of ST-2-013-600-2, Reactor Enclosure Cooling Water (RECW) Radiation Monitor Functional Test, the Surveillance Test Coordinator identified the as-left value of the HI-HI setpoint was above the required limit of 1050 counts per minute (CPM). The as-found value for the HI-HI setpoint was recorded as 1100 CPM as indicated on the radiation monitor analog scale. During the data review, the technician performing the test on March 24, 2008, did not identify that this value was above the required limit. Contrary to TS 3.3.7.1, Monitoring Instrumentation -

Radiation Monitoring Instrumentation, the station did not collect the required grab samples for the inoperable monitor during the effected period. The condition was caused by a less-than-adequate self-check by the technician recording the data during the functional surveillance test as well as a less-than-adequate supervisory review.

Corrective actions included a workgroup stand-down to reinforce the consequences of not applying the barriers that are designed for error prevention and the addition of independent reviews of surveillance test data. The event was documented in Exelons corrective action program as IR 763510. The enforcement aspects of this issue are discussed in section 4OA7. This LER is closed.

4OA6 Meetings, Including Exit

Exit Meeting Summary

On July 7, 2008, the resident inspectors presented the inspection results to Mr. C. Mudrick and other members of his staff. The inspectors confirmed that proprietary information was not included in the inspection report.

4OA7 Licensee-Identified Violations

The following violations of very low safety significance (Green) were identified by Exelon and are violations of NRC requirements which met the criteria of Section VI of the NRC Enforcement Policy, NUREG-1600, for disposition as NCVs.

• Technical Specification 3.3.7.1, Monitoring Instrumentation - Radiation Monitoring Instrumentation, requires one operable reactor enclosure cooling water (RECW) system radiation monitor channel at all times. Action 72 of Table 3.3.7.1-1 requires obtaining a grab sample every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with the required monitor inoperable. Contrary to TS 3.3.7.1, the required RECW Radiation Monitor was inoperable in Unit 2 from March 24, 2008 until April 15, 2008 without obtaining a grab sample every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The event is documented in Exelons CAP as IR 763510. The finding was of very low safety significance because it does not represent an open pathway in the physical integrity of reactor containment.

• Technical Specification 3.9.2, Refueling Operations - Instrumentation, requires an operable source range monitor (SRM) in the quadrant where core alterations are being performed when in Operational Condition 5 (OPCON 5). If this requirement is not satisfied, the operators are required to immediately suspend all operations involving core alterations and insert all insertable control rods.

Contrary to TS 3.9.2, on March 16, 2008, with Unit 1 in OPCON 5, a control rod was withdrawn with the required source range monitor in the affected core quadrant inoperable. The event is documented in Exelons CAP as IR 750227.

The finding is of very low safety significance because the finding did not require quantitative assessment per Checklist 7 of Attachment 1 to IMC 0609, Appendix G, Shutdown Operations Significance Determination Process.

ATTACHMENT:

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Exelon Generation Company

C. Mudrick, Site Vice President

E. Callan, Plant Manager

D. DiCello, Manager, Radiation Protection

R. Dickinson, Director, Engineering

P. Gardner, Director, Operations

R. Kreider, Manager, Regulatory Assurance

M. Jesse, Manager, Nuclear Oversight

S. Bobyock, Manager, Plant Engineering

M. Crim, Manager, Operations Services

C. Gray, Manager, Radiological Engineering

R. Harding, Engineer, Regulatory Assurance

J. Berg, System Manager, HPCI

J. George, System Manager, RHR

M. Gift, System Manager, Radiation Monitoring Systems

L. Lail, System Manager, EDG

R. Gosby, Radiation Protection Technician, Instrumentation

D. Malinowski, Simulator Instructor

J. Sprucinski, Senior Radiation Protection Technician

LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED

Opened

None

Closed

05000353/02008-003 LER Condition Prohibited By Technical Specifications Due To Inoperable Radiation Monitor (Section 4OA3.4)

05000352/02008-001 LER Source Range Monitor Inoperable While Control Rod Moved (Section 4OA3.2)

05000352/02008-002 LER Unit 1 Trip Due to Actuation of Power Load Unbalance (Section 4OA3.3)

Opened and Closed

05000352-05000353/2008003-01 NCV Failure to Correct Adverse Condition Associated with Motor Operated Valves (Section 4OA2.4)

Discussed

None