IR 05000352/2007005
| ML080450352 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 02/14/2008 |
| From: | Paul Krohn Reactor Projects Region 1 Branch 4 |
| To: | Pardee C Exelon Generation Co |
| KROHN, PG | |
| References | |
| IR-07-005 | |
| Download: ML080450352 (34) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ary 14, 2008
SUBJECT:
LIMERICK GENERATING STATION - NRC INTEGRATED INSPECTION REPORT 05000352/2007005 AND 05000353/2007005
Dear Mr. Pardee:
On December 31, 2007, 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 January 18, 2007, 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.
Based on the results of this inspection, no findings of significance were identified.
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 05000352/2007005 and 05000353/2007005 w/Attachment: Supplemental Information
SUMMARY OF FINDINGS
IR 05000352/2007005, 05000353/2007005; 10/01/2007 - 12/31/2007; Limerick Generating
Station, Units 1 and 2; Routine Integrated Report.
The report covered a three-month period of inspection by resident inspectors and announced inspections by reactor inspectors. 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.
NRC-Identified and Self-Revealing Findings
No findings of significance were identified.
Licensee-Identified Violations
None.
REPORT DETAILS
Summary of Plant Status
Unit 1 began this inspection period operating at full rated thermal power (RTP) and operated at full power the entire report period with the exception of routine control rod adjustments.
Unit 2 began this inspection period operating at full RTP and operated at full power the entire report period with the exception of routine control rod adjustments.
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity
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 (ST), or potentially degraded. The inspectors used plant Technical Specifications (TS),
Exelon operating procedures, plant piping and instrumentation drawings (P&IDs), and the Updated Final Safety Analysis Report (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:
- Unit 1 Reactor Core Isolation Cooling (RCIC) system;
- Unit 1 A Core Spray (CS) System with 1B CS Out of Service for Maintenance; and
- Unit 2 High Pressure Coolant Injection (HPCI) system.
b. Findings
No findings of significance were identified.
1R05 Fire Protection
Fire Protection - Tours (71111.05Q - 10 samples)
a. Inspection Scope
The inspectors conducted a tour of the ten 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:
- Unit 2 Battery Room 427;
- Diesel-Driven Fire Pump Room;
- Unit 1 Residual Heat Removal (RHR) Heat Exchanger and Pump Rooms;
- Unit 1 RCIC Pump Room;
- D12 Diesel Generator Room during Monthly ST;
- Auxiliary Equipment Room;
- Unit 2 HPCI Pump Room;
- Unit 2 Safeguard System Access Area Room;
- Unit 1 Standby Liquid Control and General Equipment Areas; and
- Unit 1 CS Pump Rooms A and C.
b. Findings
No findings of significance were identified.
1R07 Heat Sink Performance
a. Inspection Scope
The inspectors reviewed the results of Exelons inspections of the 1C RHR Pump Motor Oil Cooler. The inspectors also reviewed the results of performance testing to assess the capability of the oil cooler to operate as designed. The inspectors reviewed Exelons response to Generic Letter (GL) 89-13 and their implementation of a testing and maintenance program for safety-related heat exchangers to meet the requirements of GL 89-13. The documents reviewed are listed in the Attachment.
b. Findings
No findings of significance were identified.
1R11 Licensed Operator Requalification Program -
.1 Resident Inspector Quarterly Review
a. Inspection Scope
On October 18, 2007, the inspectors observed two licensed operator requalification simulator scenarios. The first scenario included a simulated control rod insertion, reactor water cleanup system leak, and a failure of the reactor to scram automatically. The second scenario included a simulated loss of Division One direct current electrical power, a drywell unidentified water leak, and a loss of high pressure reactor water injection. The inspectors observed the performance of both operating crews responding to the simulator scenarios. The inspectors assessed 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 observed critiques from all the training evaluators at the conclusion of each scenario. The documents reviewed are listed in the Attachment.
b. Findings
No findings of significance were identified.
.2 Biennial Review
a. Inspection Scope
The following inspection activities were performed using NUREG 1021, Revision 9, Operating Licensings Examination Standards for Power Reactors, Inspection Procedure Attachment 71111.11, Licensed Operator Requalification Program, Appendix A, Checklist for Evaluating Facility Testing Material, and Appendix B, Suggested Interview Topics.
The inspectors reviewed documentation of operating history since the last requalification program inspection. Documents reviewed included NRC inspection reports and Exelon condition reports that involved human performance issues. The purpose of the review was to ensure operational events that occurred during the last two years were not indicative of possible training deficiencies. The inspectors also discussed facility operating events with the resident staff.
The inspectors reviewed the comprehensive written examinations, scenarios, and job performance measures (JPMs) that the facility administered during the weeks of October 22 and 29, 2007, to ensure the quality of these examinations met or exceeded the criteria established in the Examination Standards and 10 CFR 55.59. The inspectors observed facility staff administer opening examinations (JPMs and scenarios) to four crews.
Conformance with Simulator Specified in 10 CFR 55.46 The inspectors observed simulator performance during the conduct of the examinations, and reviewed simulator discrepancy reports to verify facility staff were complying with the requirements of 10 CFR 55.46. The inspectors reviewed a sample of simulator tests including transient, normal, and steady state tests, as well as core performance tests.
Conformance with Operator Licensing Conditions The inspectors verified the operators were complying with the conditions of their license by reviewing the following:
- Six medical records. The records were complete; restrictions noted by the doctor were reflected on the individuals license; and physical exams were given within 24 months;
- Five proficiency watch-standing records and one reactivation record. Records indicated the licensed operators conformed with proficiency and reactivation watch-standing requirements of 10 CFR 55.53; and
- Remediation training records for eight licensed operators. These operators had failed either the scenario portion of an annual operating test, the JPM portion of an annual operating test, or a comprehensive written exam. The remediation records were acceptable.
Exelons Feedback system The inspectors interviewed operator requalification instructors, training and operations management, and two licensed operators for feedback regarding the implementation of the licensed operator requalification program. Interview results indicated that the requalification program was meeting the operators needs; was responsive to their recommended changes; and that the program administrator had modified course content to include issues documented in recent industry operating experience and licensee event reports.
On November 6, 2007, the inspectors conducted an in-office review of licensee requalification examination results. These results reflected the operators performance on the annual operating tests and the comprehensive written examinations. The inspection assessed whether pass rates were consistent with the guidance of NRC Manual Chapter 0609, Appendix I, Operator Requalification Human Performance Significance Determination Process (SDP). The inspectors verified that:
- Crew failure rate on the dynamic simulator was less than 20 percent (failure rate was 0 percent);
- Individual failure rate on the dynamic simulator test was less than or equal to 20 percent (failure rate was 0 percent);
- Individual failure rate on the walkthrough test (JPMs) was less than or equal to 20 percent (failure rate was 4.9 percent);
- Individual failure rate on the comprehensive written exam was less than or equal to 20 percent (failure rate was 4.9 percent); and
- More than 75 percent of the individuals passed all portions of the exam (90.2 percent of the individuals passed all portions of the exam).
The documents reviewed are listed in the Attachment.
b. Findings
No findings of significance were identified.
.3 Biennial Requalification Review - Limited Senior Reactor Operator (LSRO) -
(71111.11B - 1 sample)
a. Inspection Scope
On December 5, 2007, the inspectors conducted an in-office review of licensee annual operating tests for Limited Senior Reactor Operator (LSRO) licenses in 2007. The inspection assessed whether pass rates were consistent with the guidance of NRC Manual Chapter 0609, Appendix I, Operator Requalification Human Performance Significance Determination Process (SDP). The inspectors verified that:
- Crew failure rate was less than 20 percent (crew failure rate was 0 percent);
- Individual failure rate on the dynamic simulator test was less than or equal to
- 20 percent (individual failure rate was 0 percent);
- Individual failure rate on the walk-through test was less than or equal to 20 percent. (individual failure rate was 0 percent); and
- Overall pass rate among individuals for all portions of the exam was greater than or equal to 75 percent. (overall pass rate was 100 percent).
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:
- Toxic Gas Analyzers (a)(1) Determination, IR 616714; and
- Unit 2 RCIC System.
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 risk assessments for the following:
- Unit 1 Division 4 Trip Unit Inverter Power Failure, IR 686796;
- B Control Room Emergency Fresh Air System (CREFAS) Trouble Alarm, IR 698223;
- D1 Diesel Generator Starting Air Solenoid Valve Porting Air Continuously, IR 703874; and
- Unit 1 and Unit 2 Maintenance Risk Assessments for Work Week 0751.
b. Findings
No findings of significance were identified.
1R15 Operability Evaluations
a. Inspection Scope
For the seven 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 (IRs) 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:
- Standby Liquid Control Setpoint Margin Enhancement, IR 693501;
- Control Rods 02-19 and 06-47 High Temperatures >350° Fahrenheit, IR 684550;
- 1B Core Spray Surge Chamber Low Level Alarm, IR 674173;
- Unit 2 Main Stop Valve #2 Pilot Valve has Wrong Component Installed, IR 694712;
- Unit 2 Drywell Air Cooler Drain Flow Monitor, IR 683532;
- 1GTB-CG501 M1 Relay Damaged for D13 Diesel Generator, IR 690634; and
- Vendor Supplied HV-052-1
- (2) 08-OP Actuator, IR 509511.
b. Findings
No findings of significance were identified.
1R19 Post-Maintenance Testing
a. Inspection Scope
The inspectors reviewed the four 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 applicable 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:
- 1B RHR Pump, Valve, and Flow Test following a planned system maintenance period;
- D12 Diesel Generator Fast Start Operability Test Run following replacement of relays on D12 Emergency Diesel Generator;
- D11 Diesel Generator Test Run following air valve replacement; and
- 1B Core Spray Pump, Valve, and Flow Test following a planned system maintenance period.
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 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-6-051-233-2, 2C RHR Pump, Valve, and Flow Test;
- ST-6-051-234-2, 2D RHR Pump, Valve, and Flow Test;
- Units 1 and 2 Drywell Floor Drain Sump/Equipment Drain Tank Surveillance Log/OPCON 1, 2, 3;
- ST-6-092-311-2, D21 Diesel Generator Slow Start Operability Test Run; and
- ST-6-055-230-1, Unit 1 HPCI Pump, Valve, and Flow Test.
b. Findings
No findings of significance were identified.
1R23 Temporary Plant Modifications
a. Inspection Scope
The inspectors reviewed the temporary modification listed below to ensure that installation of the test equipment did not adversely affect systems important to safety.
The inspectors compared the temporary modification with the UFSAR and TSs to verify that the modification did not affect system operability or availability. The inspectors ensured that station personnel implemented the modification in accordance with the applicable temporary configuration change process. The inspectors also reviewed the impact on existing procedures to verify Exelon made appropriate revisions to reflect the temporary configuration change. The documents reviewed are listed in the Attachment.
The inspectors reviewed the following:
- Installation of Test Equipment on Unit 1 Main Generator Voltage Regulator.
b. Findings
No findings of significance were identified.
RADIATION SAFETY
Cornerstone: Public Radiation Safety
2PS1 Radioactive Gaseous and Liquid Effluent Treatment and Monitoring Systems (71122.01- 11 samples)
a. Inspection Scope
During the period December 17 thru 21, 2007, the inspector conducted the following activities to verify Exelon was properly maintaining the gaseous and liquid effluent processing systems to ensure that radiological releases were properly mitigated, monitored, and evaluated with respect to public exposure. The inspector reviewed implementation of these controls against the criteria contained in 10 CFR Part 20 and Part 50, Exelons Offsite Dose Calculation Manual (ODCM), and Exelons procedures.
This inspection activity represents completion of eleven samples relative to this inspection area. The documents reviewed are listed in the Attachment. The inspector performed the following samples:
- The inspector reviewed the 2005 and the 2006 Annual Radiological Effluent Release Reports to verify that Exelon implemented the effluents program as required by Revision 23 of the ODCM. As part of this review, the inspector evaluated changes made to the ODCM in 2005 and 2006 to determine if the changes affected Exelons ability to maintain doses as low as is reasonably achievable;
- The inspector walked down the major components of the Unit 1 and Unit 2 gaseous and liquid release monitoring systems, to verify that the system configurations complied with the UFSAR descriptions, and to evaluate equipment material condition. The inspector also reviewed the completed ST procedure associated with each monitor to demonstrate instrument operability.
- The inspector reviewed the relevant ST procedures and observed technicians collecting weekly air particulate filter and iodine cartridge samples. Airborne particulate and iodine samples were taken from the North Stack monitors (ST-5-076-815-0) and South Stack monitors (ST-5-076-815-1&2);
- The inspector reviewed the air cleaning system ST results for the High Efficiency Particulate-Absolute (HEPA) and charcoal filtration systems installed in Unit 1 and Unit 2 to ensure the components met their acceptance criteria, and discussed the results with the cognizant system manager. The inspector confirmed that the air flow rates were consistent with the UFSAR values. Systems reviewed included the A and B Standby Gas Treatment Systems, and the A and B Reactor Enclosure Recirculation Systems;
- The inspector reviewed the most current liquid and gaseous effluent monitor functional test results and calibration records to verify that the associated isolation functions and alarms were operable. The inspector evaluated the effluent radiation monitor setpoints for agreement with the ODCM requirements. Monitors reviewed included the North and South Stack monitors and the Liquid Radwaste Effluent monitor;
- The inspector reviewed liquid effluent discharge permits for the period of October 2005 through November 2007, and the associated ST procedure, Radwaste Discharge Permit (ST-5-061-570-0), for accuracy and completeness;
- The inspector reviewed liquid and gaseous effluent monthly, quarterly, and annual dose calculations for the period October 2005 through November 2007 to ensure that Exelon properly calculated the offsite dose from effluent releases, in accordance with the ODCM, and to determine if Exelon exceeded any performance indicator (PI)criteria contained in Appendix I of 10 CFR 50;
- The inspector reviewed the calibration records and quality control records for laboratory counting instrumentation (gamma detectors 1, 2, 3, and 4, and a liquid scintillation detector) used to characterize and quantify effluent samples. The inspector reviewed the results of Exelons quarterly inter-laboratory (cross checks from the first quarter 2006 through the first quarter 2007) comparison program to verify the accuracy of effluent sample analyses performed by Exelon and to ensure that discrepancies were appropriately resolved;
- The inspector reviewed and discussed with station personnel the validation and verification results for the effluent software to ensure the software in use provides accurate dose calculations;
- The inspector reviewed relevant IRs, an Effluents Control Program self-assessment, an effluents program audit, and Nuclear Oversight Objective Evidence reports to evaluate Exelons effectiveness for identifying, evaluating, and resolving effluent control issues. The inspector conducted this review against the criteria contained in 10 CFR 20, TSs, and Exelons procedures; and
- The inspector reviewed Exelons actions to evaluate and monitor potential ground water pathways that may contain radioactive materials from past spills and leaks.
Included in this review were the Radiological Groundwater Protection Program procedure (CY-AA-171-400) and implementing procedures, the hydrogeologic investigative report, the monitoring well site map, recent sampling results, and the site 10 CFR 50.75(g) decommissioning records.
b. Findings
No findings of significance were identified.
2PS3 Radiological Environmental Monitoring Program (REMP) and Radioactive Material Control Program (71122.03 - 11 samples)
a. Inspection Scope
The inspector conducted the following activities to verify that Exelon implemented the radiological environmental monitoring program (REMP) consistent with the site TSs and the Off-Site Dose Calculation Manual (ODCM) to validate that radioactive effluent releases met the design objectives of Appendix I to 10 CFR 50.
Additionally, the inspector verified that radiological surveys and controls were adequate to prevent the inadvertent release of radioactive material into the public domain. The inspector reviewed implementation of these controls against the criteria contained in 10 CFR 20 and 50, relevant TSs, and Exelon procedures.
The documents reviewed are listed in the Attachment. The inspector reviewed the following samples:
REMP Inspections (November 13 - 16, 2007)
- The inspector reviewed the 2005 and 2006 Annual Radiological Environmental Operating Reports and the 2006 Land Use Census Report to verify that the environmental monitoring programs were implemented as required by the ODCM (Revision 23);
- The inspector walked down four of six air sampling stations (Nos. 10S3, 11S1, 13C1, 14S1), five of five cows milk sampling stations (Nos.10F4, 18E1, 19B1, 23F1, 25C1), one of three vegetation sampling stations (No.13S3), four of four drinking water stations (Nos. 15F4, 15F7, 16C2, 28F3 ), one of three river sediment sampling locations (No. 16B2), two of two surface water sampling stations, and 16 of 40 thermoluminescent (TLD) monitoring stations. The inspector determined if sampling locations were as described in the ODCM, and evaluated the sampling equipment material condition;
- As part of the walk down, the inspector observed the technician collect and prepare cows milk samples for analysis, demonstrate water sample collection techniques, and verified that sampling techniques were performed in accordance with procedures;
- Based on direct observation and review of records, the inspector verified that the meteorological instrumentation was operable, calibrated, and maintained in accordance with the guidance contained in the UFSAR, NRC Safety Guide 23, and Exelon procedures. The inspector verified that the meteorological data readout and recording instruments in the control room and primary and backup towers were operable for wind direction, wind speed, temperature, and temperature difference.
The inspector confirmed that redundant instrumentation was operable and that the annualized recovery rate for meteorological data was greater that 90 percent.
- During walkdowns, the inspector had technicians demonstrate the air and water sampling equipment was properly operating;
- The inspector reviewed IRs, Nuclear Oversight Audit and Objective Evidence Reports, management evaluations of sample collection, REMP contractor audits, and departmental self-assessment reports relevant to the ODCM requirements, to evaluate the threshold for which issues are entered into the corrective action program, the adequacy of subsequent evaluations, and the effectiveness of the resolution. The inspector also reviewed monthly RETS/ODCM effluent occurrence reports to evaluate the adequacy and timeliness of PI information;
- The inspector reviewed the results of Exelons quarterly laboratory cross-check program to verify the accuracy of Exelons environmental air filter, charcoal cartridge, water, biota, and milk sample analyses; and
- The inspector reviewed any significant changes made by Exelon to the ODCM as a result of changes to the land use census or sampler station modifications since the last inspection. The inspector also reviewed technical justifications for any change in sampling location or frequency and verified Exelon performed the reviews required to ensure that the changes did not affect its ability to monitor the radiological condition of the environment.
REMP Inspections (December 17 - 21, 2007)
- The inspector reviewed the REMP contractors procedure and observed the technician collecting environmental air particulate and air iodine samples at four locations (Nos. 10S3, 11S1, 13C1, 14S1) as specified in the ODCM. The inspector evaluated the material condition and the operability of the air sampling equipment, and confirmed that the technician complied with the sampling procedure.
Unrestricted Release of Material from the Radiologically Controlled Area (RCA)
- The inspector reviewed the contamination control procedures and guidance provided to personnel for monitoring potentially contaminated material leaving the RCA for unrestricted use; and
- The inspector inspected the radiation monitoring instrumentation (SAM-9, SAM-11, Frisker) to ensure it was appropriate for the radiation types potentially present, and to ensure that it was calibrated with appropriate radiation sources. The inspector reviewed Exelons criteria for the survey and release of potentially contaminated material, verified that there was guidance on how to respond to an alarm which indicates the presence of contamination, and reviewed instrument alarm set points to ensure that radiation detection sensitivities are consistent with the NRC guidance contained in IE Circular 81-07 and IE Information Notice 85-92 for surface contamination, and HPPOS-221 for volumetrically contaminated material. The inspector also reviewed Exelons procedures and records to verify that the radiation detection instrumentation was used at its typical sensitivity level based on appropriate counting parameters. The inspectors verified that Exelon has not established a release limit by altering the instruments sensitivity through such methods as raising the energy discrimination level or locating the instrument in a high radiation background area.
b. Findings
No findings of significance were identified.
OTHER ACTIVITIES
4OA1 Performance Indicator (PI) Verification
a. Inspection Scope
The inspector sampled Exelons submittal of the initiating events, mitigating systems, and barrier integrity performance indicators listed below to verify the accuracy of the data recorded from the third quarter of 2006 through the third quarter of 2007. 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 main control room logs, issue reports, power history curves, work orders, and Mitigating System Performance Index (MSPI)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
. The inspectors performed the following samples:
Cornerstone: Initiating Events
- Unit 1 Unplanned Scrams per 7000 Critical Hours;
- Unit 2 Unplanned Scrams per 7000 Critical Hours;
- Unit 1 Unplanned Scrams with Complications; and
- Unit 2 Unplanned Scrams with Complications.
Cornerstone: Mitigating Systems
- Unit 1 Residual Heat Removal MSPI;
- Unit 2 Residual Heat Removal MSPI;
- Unit 1 Cooling Water Systems MSPI;
- Unit 2 Cooling Water Systems MSPI;
- Unit 1 Safety System Functional Failures; and
- Unit 2 Safety System Functional Failures.
Cornerstone: Barrier Integrity
- Unit 1 Reactor Coolant System Leak Rate;
- Unit 2 Reactor Coolant System Leak Rate;
- Unit 1 Reactor Coolant System Activity; and
- Unit 2 Reactor Coolant System Activity.
Cornerstone: Occupational Radiation Safety
- Occupational Exposure Control Effectiveness The inspector reviewed implementation of Exelons Occupational Exposure Control Effectiveness Performance Indicator Program. Specifically, the inspector reviewed IRs and associated documents for occurrences involving locked high radiation areas, very high radiation areas, and unplanned exposures against the criteria specified in NEI 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 5, to verify that Exelon identified and reported all occurrences that met the NEI criteria as performance indicators.
Cornerstone: Public Radiation Safety
- RETS/ODCM Radiological Effluent Occurrences The inspector reviewed relevant effluent release condition reports for the period October 1, 2006 through September 30, 2007, for issues related to the public radiation safety performance indicator, which measures radiological effluent release occurrences that exceed 1.5 mrem/qtr whole body or 5.0 mrem/qtr organ dose for liquid effluents; 5mrads/qtr gamma air dose, 10 mrad/qtr beta air dose, and 7.5 mrads/qtr for organ dose for gaseous effluents. This review included monthly and quarterly projected dose assessment results due to radioactive liquid and gaseous effluent releases, and dose assessment procedures to ensure Exelon met all the requirements of the performance indicator from the fourth quarter 2006 through the third quarter 2007.
Cornerstone: Physical Protection
- Personnel Screening; and
- Protected Area Security Equipment.
The inspector reviewed Exelons programs for gathering, processing, evaluating, and submitting data for the fitness-for duty, personnel screening, and protected area security equipment PIs. The inspector verified that the PIs had been properly reported as specified in NEI 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 5. The review included Exelons tracking and trending reports, personnel interviews, and security event reports for the PI data collected since the last security baseline inspection. The inspector noted from Exelons submittal that there were no reported failures to properly implement the requirements of 10 CFR 73 and 10 CFR 26 during the reporting period.
b. Findings
No findings of significance were identified.
4OA2 Identification and Resolution of Problems
.1 Review of Items Entered into the Corrective Action Program (CAP)
a. Inspection Scope
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 performed screening of all items entered into Limericks CAP. The inspectors accomplished this by reviewing each new condition report, attending management review committee meetings, and accessing Exelons computerized database.
b. Assessment and Observations No findings of significance were identified. The inspectors observed that issues selected for review were appropriately categorized and prioritized in accordance with Exelons corrective action process.
.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 trends that could indicate the existence of a more significant safety issue. The inspectors review was focused on corrective maintenance issues identified within the CAP. The review also included a sample of system health reports and System Health Indicator Program (SHIP) Chronic Problem reports from June and September 2007.
b. Assessment and Observations No findings of significance were identified. The inspectors observed that issues selected for review were appropriately categorized and prioritized in accordance with Exelons corrective action process.
.3 Annual Sample: Emergency Service Water (ESW) Alarms
a. Inspection Scope
The inspector reviewed IRs associated with alarms on the ESW system to verify that prioritization of the resolution of the issue was commensurate with the issues safety significance. The inspector reviewed the Issue Identification and Screening Procedure to verify that the significance classification of the issues was in accordance with Exelons procedures. The inspector interviewed the system manager and reviewed work orders and procedures to verify corrective actions taken were appropriate.
b. Assessments and Observations No findings of significance were identified.
The inspectors noted observations regarding timeliness of maintenance and nuisance alarms. With respect to the timeliness of maintenance, there have been nine IRs written on flow instrument FI-011-012B, B ESW Differential Flow, since 1998 for high differential flow alarms. In August 2004, it was recommended that the instrument be replaced at the next scheduled opportunity. The work has been rescheduled eight times since then, and has most recently been rescheduled to week 23 of 2008.
With respect to nuisance alarms, annunciator Service Water ESW Auto Initiated Valve Not Fully Open/Closed will alarm when an ESW pump starts and one of the six automatically repositioning MOVs does not complete its stroke in 10 seconds. The alarm occurs each time an ESW pump is started because the slowest valve can take up to 48 seconds to reposition. According to the system manager, the system has been this way since plant startup, and the alarm is expected. Additionally, a review of two procedures, ST-6-011-231-0, A Loop ESW Pump, Valve, and Flow Test, and RT-2-011-251-0, ESW Loop A Flow Balance, does not indicate that the alarm is expected when starting an ESW pump. Though these items impact the quantity of nuisance alarms received in the Main Control Room, the inspectors verified that neither of these issues affect the operability of the ESW system.
.4 Annual Sample: Unit 1 and Unit 2 Recirculation Pump Seal Failures
a. Inspection Scope
The inspectors reviewed Exelons corrective actions associated with IRs 489517 and 613865, regarding the failures of the 1A and 2A reactor recirculation pump (RRP) seals, respectively. The inspectors reviewed the apparent cause evaluation of the May 2006 1A RRP seal failure and the root cause investigation report of the April 2007 2A RRP seal failure. Both seal failures followed outages in which a piping modification had been installed to apply a differential pressure to the RHR shutdown cooling injection check valve by routing fluid from the back of the valve disc to the suction valve of the associated recirculation pump. The inspectors also reviewed the modification packages, piping and instrument drawings (P&IDs) for the RHR and reactor recirculation systems, venting procedures, vendor manuals for the pump seals, and interviewed the system manager for these systems.
b. Assessments and Observations No findings of significance were identified.
In the apparent cause evaluation of the 1A RRP seal, examination of the degraded seal faces established that severe pitting, blistering, and erosion existed and had likely been the result of air intrusion following the piping modification and subsequent venting which had been inadequate. Exelon improved the venting procedure as a corrective action.
The piping modification had also been installed in piping associated with the 1B RRP seal during the same outage, and the 1B RRP seal performed acceptably.
In the root cause investigation report of the 2A RRP seal, Exelon noted that the prior evaluation of the 1A RRP seal did not identify how the air initially entered the [RHR]
system or how the air migrated through the system. The root cause investigation reached similar conclusions that air had entered the RHR system during the modification and had not been completely vented prior to operation of the pump, and was unable to be specific about air intrusion and migration. The corrective actions included additional improvements to the venting procedure, ultrasonic examinations to confirm the effectiveness of the revised venting process, and operational procedure changes to isolate the check valve differential pressure line prior to implementing shutdown cooling.
The inspectors determined that the root cause investigation was thorough, detailed, and reasonable, and that the corrective actions were appropriate and likely to address the root cause and causal factors. However, the inspectors noted that Exelon remained unable to explain how the 1A and 2A RRP seals had been degraded by the same circumstances and factors under which the 1B RRP had been unaffected and continued to perform acceptably. Combined with the inability to specifically determine the air intrusion and migration, this provides the possibility that planned corrective actions have overlooked a factor which could again cause seal degradation.
.5 Annual Sample: HPCI and RCIC Gross Fail Alarms
a. Inspection Scope
The inspectors reviewed Exelons corrective actions associated with IR 227455 regarding gross fail alarms associated with RCIC trip units FIS-049-*N651 and FS-049-
These trip units supply an input signal to the control logic for the RCIC minimum flow valves. The inspectors reviewed corrective actions for similar issue reports, the IR history of the numerous alarms, applicable test and venting procedures, preventative maintenance documentation, system flow diagrams, and interviewed the system manager for the HPCI and RCIC systems regarding the expected system response to the instrument gross fail alarms. The inspectors also evaluated Exelons actions against the requirements of the corrective action program.
b. Assessments and Observations No findings of significance were identified.
In IR 227455, which was written on June 10, 2004, Exelon identified that numerous RCIC trip unit gross fail status lights and RCIC Out-of-Service alarms were received during performance of various HPCI and RCIC STs on both Unit 1 and Unit 2. At that time, Exelon suspected that air in the instrument lines of the flow transmitters that supply the trip units with a signal to be the cause of the gross fail alarms. Exelon created preventative maintenance (PM) tasks 385032 and 385033 to vent the instrument lines on a yearly basis. The station performed these PMs in September 2005, 2006, and 2007 for Unit 1 and September 2005 and August 2006 for Unit 2.
Since the PMs were initially performed, Exelon identified two instances of the gross fail alarms on September 6, 2006, and December 21, 2006 on Unit 1, and one instance on June 20, 2006 on Unit 2. Exelon attributed one of the two instances on Unit 1 to unacceptable venting during system performance. Following these additional occurrences, the station generated additional IRs (579970, 579917, and 579921) to decrease the gross fail setpoints of the instruments to lower their sensitivity to hydraulic perturbations in the systems. No additional instances of gross fail alarms were noted following this corrective action. Exelon determined and the inspectors confirmed that the gross fail alarms would not prevent the HPCI and RCIC systems from performing their safety functions.
4OA6 Meetings, Including Exit
Exit Meeting Summary
On January 18, 2007, 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.
ATTACHMENT:
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Exelon Generation Company
- C. Mudrick, Site Vice President
- E. Callan, Plant Manager
- D. DiCello, Radiation Protection Manager
- R. Dickinson, Director Engineering
- R. Kreider, Manager, Regulatory Assurance
- M. Gift, System Manager, Radiation Monitoring Systems
- R. Gosby, Radiation Protection Technician, Instrumentation
- R. Harding, Engineer, Regulatory Assurance
- D. Malinowski, Simulator Instructor
- P. Supplee, Security Manager
- B. Whitman, Security Operations Coordinator
LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
None
Closed
None
Discussed
None