IR 05000227/2016001
| ML16125A073 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 05/04/2016 |
| From: | Daniel Schroeder Reactor Projects Region 1 Branch 4 |
| To: | Bryan Hanson Exelon Generation Co, Exelon Nuclear |
| SCHROEDER, DL | |
| References | |
| IR 2016001 | |
| Download: ML16125A073 (31) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION May 4, 2016
SUBJECT:
PEACH BOTTOM ATOMIC POWER STATION - INTEGRATED INSPECTION REPORT 05000277/2016001 AND 05000278/2016001
Dear Mr. Hanson:
On March 31, 2016, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3. The enclosed inspection report documents the inspection results, which were discussed on April 18, 2016, with Mr. Michael Massaro, Peach Bottom Site Vice President, and other members of your staff.
NRC Inspectors 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 NRC-identified or self-revealing findings were identified during this inspection.
In accordance with Title 10 of the Code of Federal Regulations (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 NRCs Public Document Room or from the Publicly Available Records component of the NRC's Agencywide Documents Access and Management 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/
Daniel L. Schroeder, Chief Reactor Projects Branch 4 Division of Reactor Projects Docket Nos. 50-277 and 50-278 License Nos. DPR-44 and DPR-56
Enclosure:
Inspection Report 05000277/2016001 and 05000278/2016001 w/Attachment: Supplementary Information
REGION I==
Docket Nos. 50-277 and 50-278 License Nos. DPR-44 and DPR-56 Report No. 05000277/2016001 and 05000278/2016001 Licensee: Exelon Generation Company, LLC Facility: Peach Bottom Atomic Power Station, Units 2 and 3 Location: Delta, Pennsylvania Dates: January 1, 2016 through March 31, 2016 Inspectors: J. Heinly, Senior Resident Inspector B. Smith, Resident Inspector P. Boguszewski, Reactor Engineer C. Graves, Health Physicist P. Ott, Operations Engineer Approved By: Daniel L. Schroeder, Chief Reactor Projects Branch 4 Division of Reactor Projects Enclosure
SUMMARY
IR 05000277/2016001, 05000278/2016001, 01/01/2016 - 03/31/2016; Peach Bottom Atomic
Power Station (PBAPS), Units 2 and 3; Integrated Inspection Report.
This report covered a three-month period of inspection by resident inspectors, and announced baseline inspections performed by regional inspectors. The Nuclear Regulatory Commissions (NRC) program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, Revision 5.
Cornerstone: Initiating Events, Mitigating Systems, and Barrier Integrity
No NRC-identified or self-revealing findings were identified during this inspection.
Other Findings
A violation of very low safety significance that was identified by Exelon was reviewed by the inspectors. Corrective actions taken or planned by Exelon have been entered into Exelons corrective action program (CAP). This violation and corrective action tracking number are listed in Section 4OA7 of this report.
REPORT DETAILS
Summary of Plant Status
Unit 2 began the inspection period at 100 percent rated thermal power (RTP) and remained at 100 percent power until an emergent downpower to 80 percent RTP on March 28, 2016, for the loss of a 480V electrical bus. The bus was restored and full power was restored the same day.
Unit 2 remained at full power until the end of the inspection period.
Unit 3 began the inspection period at 100 percent RTP. Unit 3 downpowered to 75 percent power on February 11, 2016, to support planned testing and control rod sequence exchange and returned to full power on February 12, 2016. Unit 3 remained at or near full power until the end of the inspection period.
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity
1R01 Adverse Weather Protection
Readiness for Impending Adverse Weather Conditions
a. Inspection Scope
The inspectors reviewed PBAPS preparation and response to sheet ice on the Susquehanna River from January 20-22, 2016. The inspectors reviewed the implementation of PBAPS' adverse weather preparation procedures before the onset of the adverse weather condition. The inspectors walked down the river intake structure and verified ice removal systems and equipment were available. The inspectors verified that operator actions defined in PBAPS adverse weather procedure maintained the readiness of essential systems. In addition, the inspectors observed the operators manual actions in response to sheet ice build up on the trash racks. The inspectors discussed readiness and staff availability for adverse weather response with operations and work control personnel. Documents reviewed for each section of this inspection report are listed in the Attachment.
b. Findings
No findings were identified.
1R04 Equipment Alignment
Partial System Walkdowns
a. Inspection Scope
The inspectors performed partial walkdowns of the following systems:
Unit 2 B residual heat removal (RHR) following system restoration on February 3, 2016 Unit 2 reactor core isolation cooling (RCIC) during a high-pressure coolant injection (HPCI) system outage window (SOW) on February 22, 2016 Unit 3 B and D core spray (CS) during an A RHR SOW on February 29, 2016 Unit 2 HPCI with the automatic depressurization system inoperable on March 24, 2016 The inspectors selected these systems based on their risk-significance relative to the Reactor Safety cornerstones at the time they were inspected. The inspectors reviewed applicable operating procedures, system diagrams, the Updated Final Safety Analysis Report (UFSAR), Technical Specifications (TSs), work orders (WOs), issue reports (IRs), and the impact of ongoing work activities on redundant trains of equipment in order to identify conditions that could have impacted the systems performance of its intended safety functions. The inspectors also performed field walkdowns of accessible portions of the systems to verify system components and support equipment were aligned correctly and were operable. The inspectors examined the material condition of the components and observed operating parameters of equipment to verify that there were no deficiencies. The inspectors also reviewed whether PBAPS staff had properly identified equipment issues and entered them into the CAP for resolution with the appropriate significance characterization.
b. Findings
No findings were identified.
1R05 Fire Protection
Resident Inspector Quarterly Walkdowns
a. Inspection Scope
The inspectors conducted tours of the areas listed below to assess the material condition and operational status of fire protection features. The inspectors verified that PBAPS controlled combustible materials and ignition sources were controlled in accordance with administrative procedures. The inspectors verified that fire protection and suppression equipment was available for use as specified in the area pre-fire plan, and passive fire barriers were maintained in good material condition. The inspectors also verified that station personnel implemented compensatory measures for out-of-service (OOS), degraded or inoperable fire protection equipment, as applicable, in accordance with procedures.
Unit 2/Unit 3 circulating water pump structure on February 25, 2016 Unit 2 HPCI/RCIC sump rooms on February 26, 2016 Unit 3 battery and switchgear rooms on February 26, 2016 Unit 2/Unit 3 emergency diesel generator (EDG) cardox room on March 3, 2016
b. Findings
No findings were identified.
1R06 Flood Protection Measures
Annual Review of Cables Located in Underground Bunkers/Manholes
a. Inspection Scope
During the week of March 14, 2016, the inspectors conducted an inspection of an underground manhole subject to flooding that contains cables whose failure could disable risk-significant equipment. The inspectors performed walkdowns of risk-significant areas, including manhole 89 to verify that the cables were not submerged in water, that cables and/or splices appeared intact, and to observe the condition of cable support structures. In addition, the inspectors observed ground water intrusion mitigation work activities in manhole 89. When applicable, the inspectors verified proper sump pump operation and verified level alarm circuits were set in accordance with station procedures and calculations to ensure that the cables will not be submerged.
The inspectors also ensured that drainage was provided and functioning properly in areas where dewatering devices were not installed.
b. Findings
No findings were identified.
1R07 Heat Sink Performance
a. Inspection Scope
The inspectors reviewed the 3 B' RHR cleaning on February 17, 2016 and its readiness and availability to perform its safety functions. The inspectors reviewed the design basis for the component and verified PBAPS commitments to NRC Generic Letter 89-13, Service Water System Requirements Affecting Safety-Related Equipment. The inspectors observed actual performance tests for the heat exchangers (HXs) and/or reviewed the results of previous inspections of the Unit 3 RHR HXs. The inspectors discussed the results of the most recent inspection with engineering staff and reviewed pictures of the as-found and as-left conditions. The inspectors verified that PBAPS initiated appropriate corrective actions for identified deficiencies. The inspectors also verified that the number of tubes plugged within the HX did not exceed the maximum amount allowed.
b. Findings
No findings were identified.
1R11 Licensed Operator Requalification Program and Licensed Operator Performance
.1 Quarterly Review of Licensed Operator Requalification Testing and Training
(71111.11Q - 1 sample)
a. Inspection Scope
The inspectors observed a licensed operator simulator training on February 8, 2016, that involved a Unit 2 anticipated transient without scram complicated by a RCIC steam leak.
The inspectors evaluated operator performance during the simulated event and verified completion of risk significant operator actions, including the use of abnormal and emergency operating procedures. The inspectors assessed the clarity and effectiveness of communications, implementation of actions in response to alarms and degrading plant conditions, and the oversight and direction provided by the control room supervisor. The inspectors verified the accuracy and timeliness of the emergency classifications made by the shift manager and the TS action statements entered by the operators. Additionally, the inspectors assessed the ability of the crew and training staff to identify and document crew performance problems.
b. Findings
No findings were identified.
.2 Quarterly Review of Licensed Operator Performance in the Main Control Room
(71111.11Q - 1 sample)
a. Inspection Scope
The inspectors observed and reviewed the licensed operator performance from the main control room (MCR) in response to the sheet ice event on January 20, 2016, and post-modification testing on the Unit 2 71K safety relief valve (SRV) on March 24, 2016. The inspectors observed use of and compliance with procedures, crew communications, interpretation, diagnosis, and understanding of plant alarms, use of human error prevention techniques, documentation of activities, and management oversight of the evolutions to verify that the crew was following procedures and plant expectations for conduct of operations.
b. Findings
No findings were identified.
.3 Licensed Operator Requalification Program
a. Inspection Scope
On March 29, 2016, one NRC region-based inspector conducted an in-office review of results of licensee-administered annual operating tests for 2016 for PBAPS, Units 2 and 3 operators. The inspection assessed whether pass/fail rates were consistent with the guidance of NRC Manual Chapter 0609, Appendix I, and Operator Requalification Human Performance Significance Determination Process (SDP). The review verified that the failure rate (individual or crew) did not exceed 20 percent.
None of the 68 operators failed any section of the annual exam. The overall individual failure rate was 0.0 percent.
None of the 10 crews failed the simulator test. The crew failure rate was 0.0 percent.
b. Findings
No findings were identified.
1R12 Maintenance Effectiveness
a. Inspection Scope
The inspectors reviewed the samples listed below to assess the effectiveness of maintenance activities on structures, systems, and components (SSCs) performance and reliability. The inspectors reviewed system health reports, CAP documents, maintenance WOs, and maintenance rule (MR) basis documents to ensure that PBAPS was identifying and properly evaluating performance problems within the scope of the MR. For each sample selected, the inspectors verified that the SSC was properly scoped into the MR in accordance with 10 CFR 50.65 and verified that the (a)(2)performance criteria established by the PBAPS staff was reasonable. As applicable, for SSCs classified as (a)(1), the inspectors assessed the adequacy of goals and corrective actions to return these SSCs to (a)(2) status. Additionally, the inspectors ensured that PBAPS staff was identifying and addressing common cause failures that occurred within and across MR system boundaries.
Unit 2 and Unit 3 RHR and CS room cooler system review on February 18, 2016 Unit 2 reactor protection system (RPS) review on February 22, 2016
b. Findings
No findings were identified.
1R13 Maintenance Risk Assessments and Emergent Work Control
a. Inspection Scope
The inspectors reviewed station evaluation and management of plant risk for the maintenance and emergent work activities listed below to verify that PBAPS performed the appropriate risk assessments prior to removing equipment for work. The inspectors selected these activities based on potential risk significance relative to the Reactor Safety cornerstones. As applicable for each activity, the inspectors verified that PBAPS personnel performed risk assessments as required by 10 Code of Federal Regulations (CFR) 50.65(a)(4) and that the assessments were accurate and complete. When PBAPS performed emergent work, the inspectors verified that operations personnel promptly assessed and managed plant risk. The inspectors reviewed the scope of maintenance work and discussed the results of the assessment with the stations probabilistic risk analyst to verify plant conditions were consistent with the risk assessment. The inspectors also reviewed the TS requirements and inspected portions of redundant safety systems, when applicable, to verify risk analysis assumptions were valid and applicable requirements were met.
Yellow risk during a planned Unit 3 HPCI SOW on January 20, 2016 Green risk during a planned Unit 2/Unit 3 A standby gas treatment system exhaust fan SOW on February 1, 2016 Yellow risk during a planned Unit 2 A RHR SOW on February 8, 2016 Yellow risk during a planned Unit 3 B high pressure service water (HPSW)/RHR SOW on February 16, 2016
b. Findings
No findings were identified.
1R15 Operability Determinations and Functionality Assessments
a. Inspection Scope
The inspectors reviewed operability determinations (ODs) for the following degraded or non-conforming conditions based on the risk significance of the associated components and systems:
Unit 3 RCIC governor slow response time on February 2, 2016 Unit 2 A RHR check valve swing arm detached on February 11, 2016 Unit 2 D RHR motor operated valve over thrust condition on March 9, 2016 Unit 2 K SRV intermittent ground condition on March 24, 2016 Unit 3 HPCI hi torus level switch failure on March 31, 2016 The inspectors evaluated the technical adequacy of the ODs to assess whether TS operability was properly justified and the subject component or system remained available such that no unrecognized increase in risk occurred. The inspectors compared the operability and design criteria in the appropriate sections of the TSs and UFSAR to PBAPS evaluations to determine whether the components or systems were operable.
The inspectors confirmed, where appropriate, compliance with bounding limitations associated with the evaluations, including compliance with in-service testing requirements. Where compensatory measures were required to maintain operability, such as in the case of operator workarounds (OWAs), the inspectors determined whether the measures in place would function as intended and were properly controlled by PBAPS. Based on the review of selected OWAs listed above, the inspectors verified that PBAPS identified OWAs at an appropriate threshold and addressed them in a manner that effectively managed OWA-related adverse effects on operators and SSCs.
b. Findings
No findings were identified.
1R18 Plant Modifications
Temporary Plant Modification
a. Inspection Scope
The inspectors reviewed the temporary plant modification listed below to determine whether the modification affected the safety functions of systems that are important to safety. The inspectors also reviewed 10 CFR 50.59 documentation and post-modification testing results, and conducted field walkdowns of the modifications to verify that the temporary modification to the automatic depressurization system (ADS) logic wiring did not degrade the design bases, licensing bases, and performance capability of the affected system.
Unit 2 K SRV ADS logic wiring on March 24, 2016
b. Findings
No findings were identified
1R19 Post-Maintenance Testing
a. Inspection Scope
The inspectors reviewed the post-maintenance tests (PMTs) for the maintenance activities listed below to verify that procedures and test activities tested the safety functions that may have been affected by the maintenance activity, that the acceptance criteria in the procedure were consistent with the information in the applicable licensing basis and/or design basis documents, and that the test results were properly reviewed and accepted and problems were appropriately documented. The inspectors also walked down the affected job site, observed the pre-job brief and post-job critique where possible, confirmed work site cleanliness was maintained, and witnessed the test or reviewed test data to verify quality control hold point were performed and checked, and that results adequately demonstrated restoration of the affected safety functions.
Unit 3 HPCI unplanned maintenance outage to repair the flow controller on January 1, 2016 Unit 2 A RHR planned maintenance outage on February 2, 2016 Unit 3 B HPSW/emergency service water (ESW) fan replacement on February 17, 2016 Unit 2 HPCI planned maintenance outage window on February 23, 2016 Unit 2 K SRV unplanned outage on March 24, 2016 Unit 3 RCIC remote shutdown panel flow controller replacement on March 29, 2016
b. Findings
No findings were identified.
1R22 Surveillance Testing
a. Inspection Scope
The inspectors observed performance of surveillance tests (STs) and/or reviewed test data of selected risk-significant SSCs to assess whether test results satisfied TSs, the UFSAR, and PBAPS procedure requirements. The inspectors verified that test acceptance criteria were clear, tests demonstrated operational readiness and were consistent with design documentation, test instrumentation had current calibrations and the range and accuracy for the application, tests were performed as written, and applicable test prerequisites were satisfied. Upon test completion, the inspectors considered whether the test results supported that equipment was capable of performing the required safety functions. The inspectors reviewed the following STs:
Unit 2/Unit 3 E-2 EDG 24-hour endurance run on January 28 - 30, 2016 Unit 2/Unit 3 E-3 EDG fuel oil sampling surveillance on February 10, 2016 Unit 2 HPCI logic system functional testing on March 1, 2016 Unit 2 standby liquid control (SBLC) on March 2, 2016 (in-service test)
Unit 3 HPCI biennial comprehensive test on March 22, 2016 (in-service test)
b. Findings
No findings were identified.
Cornerstone: Emergency Preparedness
1EP6 Drill Evaluation
Emergency Preparedness Drill Observation
a. Inspection Scope
The inspectors evaluated the conduct of a routine PBAPS Unit 2 emergency drill on February 8, 2016, to identify any weaknesses and deficiencies in the classification, notification, and protective action recommendation development activities. The drill required the operators to declare an Alert due to an emergency blowdown. The inspectors observed emergency response operations in the simulator, technical support center, and emergency operations facility to determine whether the event classification, notifications, and protective action recommendations were performed in accordance with procedures. The inspectors also attended the station drill critique to compare inspector observations with those identified by PBAPS staff in order to evaluate PBAPS critique and to verify whether the PBAPS staff was properly identifying weaknesses and entering them into the CAP.
b. Findings
No findings were identified.
RADIATION SAFETY
Cornerstone: Occupational Radiation Safety (OS)
2RS1 Radiological Hazard Assessment and Exposure Controls
a. Inspection Scope
During March 7 - 10, 2016, the inspectors reviewed Exelons performance in assessing and controlling radiological hazards in the workplace. The inspectors used the requirements contained in 10 CFR 20, TSs, applicable Regulatory Guides (RGs), and the procedures required by TSs as criteria for determining compliance.
Inspection Planning
The inspectors reviewed the performance indicators (PIs) for the occupational exposure cornerstone, radiation protection (RP) program audits, and reports of operational occurrences in occupational radiation safety since the last inspection.
Radiological Hazard Assessment (1 sample)
The inspectors conducted independent radiation measurements during walk-downs of the facility and reviewed the radiological survey program; air sampling and analysis; continuous air monitor use, recent plant radiation surveys for radiological work activities, and any changes to plant operations since the last inspection to verify survey adequacy any new radiological hazards for onsite workers or members of the public.
Contamination and Radioactive Material Control (1 sample)
The inspectors observed the monitoring of potentially contaminated material leaving the radiological controlled area and inspected the methods and radiation monitoring instrumentation used for control, survey, and release of that material. The inspectors selected several sealed sources from inventory records and assessed whether the sources were accounted for and were tested for loose surface contamination. The inspectors evaluated whether any recent transactions involving nationally tracked sources were reported in accordance with requirements.
Risk-Significant High Radiation Area (HRA) and Very High Radiation Area (VHRA)
Controls (1 sample)
The inspectors reviewed the procedures and controls for HRAs, VHRAs, and radiological transient areas in the plant.
Problem Identification and Resolution (1 sample)
The inspectors evaluated whether problems associated with radiation monitoring and exposure control (including operating experience) were identified at an appropriate threshold and properly addressed in the CAP.
b. Findings
No findings were identified.
2RS2 Occupational As Low As Is Reasonably Achievable (ALARA) Planning and Controls
a. Inspection Scope
During March 7-10, 2016, the inspectors assessed Exelons performance with respect to maintaining occupational individual and collective radiation exposures ALARA. The inspectors used the requirements contained in 10 CFR 20, applicable RGs, TSs, and procedures required by TSs as criteria for determining compliance.
Inspection Planning
The inspectors conducted a review of PBAPS collective dose history and trends; ongoing and planned radiological work activities; radiological source term history and trends; and ALARA dose estimating and tracking procedures.
Radiological Work Planning (1 sample)
The inspectors selected the following radiological work activities based on exposure significance for review:
Radiation Work Permit (RWP) PB-C-15-00511, Drywell Valve Maintenance and Support Activities RWP PB-C-15-00546, Drywell & Outboard Main Steam Isolation Valve Room Small Bore Pipe and Associated Work RWP PB-C-15-00609, B RHR Floating Head RWP PB-C-1500624, Unit 3 B & D RHR Rooms-Work Associated with EPU Crosstie Mod RWP PB-C-1500901, P3R20 Refuel Floor Reactor Disassembly and Re-assembly For each of these activities, the inspectors reviewed: ALARA work activity evaluations, exposure estimates, and exposure reduction requirements.
Problem Identification and Resolution (1 sample)
The inspectors evaluated whether problems associated with ALARA planning and controls were identified at an appropriate threshold and properly addressed in the CAP.
b. Findings
No findings were identified.
OTHER ACTIVITIES
4OA1 Performance Indicator (PI) Verification
.1 Unplanned Scrams, Unplanned Power Changes, and Unplanned Scrams with
Complications (6 samples)
a. Inspection Scope
The inspectors reviewed PBAPSs information submitted for the initiating events PIs listed below to assess the accuracy and completeness of the data reported to the NRC for these PIs. The PI definitions and the guidance contained in Nuclear Energy Institute (NEI) 99-02, "Regulatory Assessment Performance Indicator Guideline," Revision 7, and Exelon procedure LS-AA-2001, Collecting and Reporting of NRC PI Data, Revision 14, were used to verify that procedure and reporting requirements were met. The inspectors reviewed raw PI data collected from January 1, 2015 to December 31, 2015, and compared graphical representations from the applicable PI reports to the raw data to verify the data was included in the report. The inspectors also examined a selected sample of operations logs and plant computer thermal power data trends to verify the PI data was appropriately captured for inclusion into the PI report and that the individual PIs were correctly calculated.
Units 2 and 3 Unplanned Scrams per 7,000 Critical Hours (IE01)
Units 2 and 3 Unplanned Power Changes per 7,000 Critical Hours (IE03)
Units 2 and 3 Unplanned Scrams with Complications (IE04)
b. Findings
No findings were identified.
.2 Occupational Exposure Control Effectiveness (1 sample)
a. Inspection Scope
During March 7 - 10, 2016, the inspectors sampled licensee submittals for the occupational exposure control effectiveness PI for the period from the second quarter 2015 through fourth quarter 2015. The inspectors used PI definitions and guidance contained in the NEI Document 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 7, dated August 31, 2013, to determine the accuracy of the PI data reported.
To assess the adequacy of Exelons PI data collection and analyses, the inspectors discussed with radiation protection staff the results of their PI review, and independently reviewed electronic personal dosimetry accumulated dose alarms, dose reports, and dose assignments for any intakes that occurred during the time period. The inspectors conducted walk-downs of numerous locked high and VHRA entrances to determine the adequacy of the controls in place for these areas.
b. Findings
No findings were identified.
4OA2 Problem Identification and Resolution
.1 Routine Review of Problem Identification and Resolution Activities
a. Inspection Scope
As required by Inspection Procedure (IP) 71152, Problem Identification and Resolution, the inspectors routinely reviewed issues during baseline inspection activities and plant status reviews to verify that PBAPS entered issues into the CAP at an appropriate threshold, gave adequate attention to timely corrective actions, and identified and addressed adverse trends. In order to assist with the identification of repetitive equipment failures and specific human performance issues for follow-up, the inspectors performed a daily screening of items entered into the CAP and periodically attended condition report screening meetings. The inspectors also confirmed, on a sampling basis, that, as applicable, for identified defects and non-conformances, PBAPS performed an evaluation in accordance with 10 CFR Part 21.
b. Findings
No findings were identified.
.2 Annual Sample: Degraded Limitorque Model SMB-000 Leaf-Style Torque Switches
a. Inspection Scope
The inspectors performed an in-depth review of Exelons analysis and corrective actions associated with condition report IR 02555841, MO-2-13C-4487 Did Not Stroke Full Closed from the Main Control Room (MCR), written on September 16, 2015.
Specifically, Exelons Unit 2 RCIC Trip Throttle Valve (TTV) operator did not stroke full closed when the control switch was placed in the close direction because the operators torque switch prematurely actuated.
The inspectors assessed Exelons problem identification threshold, engineering change request (ECR), extent of condition reviews, and the prioritization and timeliness of Exelons corrective actions to determine whether Exelon was appropriately identifying, characterizing, and correcting problems associated with this issue and whether the planned or completed corrective actions were appropriate. The inspectors compared the actions taken to the requirements of Exelons CAP and 10 CFR 50, Appendix B.
In addition, the inspectors performed field walkdowns and interviewed engineering, operations and work management personnel to assess the effectiveness of the implemented corrective actions.
b. Findings and Observations
No findings were identified.
On November 18, 2014, the motor-operated valve (MOV) operator, MO-2-13C-4487, for the Unit 2 RCIC TTV failed to close during the performance of RCIC overspeed trip surveillance testing. The MOV operator is used to reset the RCIC TTV following a RCIC turbine overspeed event, but its inability to close does not impact the RCIC safety function. Following troubleshooting efforts, Exelon determined that the closed contacts on the MOV torque switch had unexpectedly tripped open, thus preventing the valve from closing. Exelon initiated IR 02413679 and determined debris buildup existed on the torque switch closed contacts. Exelon cleaned the contacts with denatured alcohol and the valve was returned to functional status following successful valve strokes. The MOV was stroked successfully during subsequent quarterly surveillance tests. However, on September 16, 2015, the MOV again failed to close because the MOVs torque switch closed contacts were tripped open, thus preventing valve motion. Exelon initiated IR 02555841, cleaned the open and closed contacts, and adjusted the torque switch setpoints. Exelon determined that the MO-2-13C-4487 torque switch leaf spring was found to be making inconsistent contact, resulting in a high resistance control circuit.
The MOV operator for the RCIC TTV has a Limitorque SMB-000 actuator with a Leaf Style torque switch. IR 02555841 specified a recommendation to replace the leaf-style SMB-000 torque switch with a more reliable C style SMB-000 torque switch.
Although the failure of MO-2-13C-4487 did not impact the safety function of the RCIC system, the inspectors identified that Exelon had over twenty leaf-style SMB-000 torque switch subcomponents per unit used in other safety related MOVs.
The inspectors noted that eleven failures of SMB-000 Leaf Style torque switches had occurred since 2013, three of those failures were identified among the Exelon fleet. On August 25, 2014, Limitorque issued a technical update along with an environmental qualification report demonstrating the acceptability of a new C Style torque switch that is not subject to a high failure rate as are the Leaf Style torque switches. The C Style torque switch was evaluated by Limitorque to be a direct replacement for the Leaf Style torque switches in SMB-000 actuators and therefore the vendor discontinued obsolete Leaf Style torque switches. Exelon initiated IR 02556564, in which Exelons engineering department recommended replacing the Leaf Style torque switch with a C Style torque switch in MOV operators via ECR 15-00469.
Exelon ECR 15-00469, Replace C Style Torque Switch for SMB-000 Operators, was not issued, however, until February 19, 2016. The inspectors observed that Exelons ECR to replace the torque switches was not timely in its implementation. However, the inspectors determined that Exelons interim actions, which were to replace any degraded leaf-style SMB-000 torque switches in safety related applications found during periodic inspections were appropriate. Exelon utilized procedure MA-AA-723-301, Periodic Inspection of Limitorque Model SMB/SB/SBD-000 through 5 MOVs, which directs the maintenance department to periodically inspect the SMB-000 torque switches for pitted, burned, corroded, or oxidized contacts among other specific criteria to determine if the leaf-style SMB-000 switch is degraded. Given the nature of the previous failures on the RCIC TTV operator, the inspectors determined the interim procedural requirements were appropriate to preclude any failures on safety-related MOVs. In addition, the inspectors determined the observation of the ECR timeliness to be minor since no failures on safety-related MOV torque switch subcomponents occurred before the ECR issue date.
The inspectors reviewed each individual leaf-style torque switch subcomponent maintenance and inspection history used in safety-related MOVs and did not identify any maintenance inspection that identified degraded contacts which necessitated an immediate replacement. Exelon documented further torque switch observations in IRs 02629710 and 02629960.
4OA3 Follow-Up of Events and Notices of Enforcement Discretion
(Closed) Licensee Event Report (LER) 05000278/2015-001: Loss of HPCI System Function as a Result of Failed Flow Controller Signal Converter On December 31, 2015, a PBAPS control room operator identified that the Unit 3 HPCI flow controller demand indicated zero percent. The flow controller was in automatic with a nominal set point of 5000 gpm. However, for the HPCI flow controller to function properly to maintain HPCI available to perform its design function in the event of an accident, controller demand is required to indicate 100 percent. The HPCI system was declared inoperable and TS 3.5.1(C) was entered. This TS allows the HPCI to be inoperable for 14 days otherwise Unit 3 must be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Subsequent troubleshooting of the HPCI flow controller found that a signal converter in the HPCI control circuitry had failed. The failure of the signal converter was determined to be a latent manufacturing issue resulting in an infant mortality of the converter. The corrective actions included replacing the signal converter and testing the HPCI system.
There were no actual safety consequences associated with this event. The inspectors reviewed LER 05000278/2015-001 and its apparent cause evaluation, and determined no findings or violations of NRC requirements existed. This LER is closed.
4OA6 Meetings, Including Exit
Quarterly Resident
Exit Meeting Summary
On April 18, 2016, the inspectors presented the inspection results to Mr. Michael Massaro, Peach Bottom Site Vice President and other members of the PBAPS staff.
The inspectors verified that no proprietary information was retained by the inspectors or documented in this report.
4OA7 Licensee-Identified Violations
The following violation of very low safety significance was identified by the licensee and is a violation of NRC requirements which meets the criteria of Section 2.3.2 of the NRC Enforcement Policy to be dispositioned as a non-cited violation (NCV).
On September 29, 2015, Exelon identified the door to the Unit 3 condensate backwash tank room was not secure. The room is controlled as a locked HRA, and a survey of the room indicated that actual radiation levels were greater than 1.0 rem/hour. TS 5.7.2.a requires, in part, that entryways to areas exceeding 1.0 rem/hour will be locked or continuously guarded to prevent unauthorized entry. Contrary to the above, on September 29, 2015, Exelon identified an area with radiation levels greater than 1.0 rem/hour with an entryway that was not locked or continuously guarded.
Traditional enforcement applies in accordance with Inspection Manual Chapter (IMC)0612, sections 0612-09 and 0612-13; and Enforcement Policy Section 2.2.4.d; because the inspectors did not identify an associated performance deficiency. Specifically, the inspectors determined that because Exelon had an acceptable door maintenance program, conducted weekly checks of LHRA doors, and has not had previous issues with unsecured doors, that the failure of the door lock mechanism was not apparent and, therefore, was not foreseeable and preventable.
The issue was considered to be a SL IV violation of TS 5.7.2.a in accordance with Enforcement Policy Section 6.1.d. In addition, IMC 0612, Appendix B, Figures 1 and 2, Issue Screening, were utilized in documenting this as a SL IV licensee-identified NCV.
The licensee took immediate corrective actions to ensure the door remained locked and documented the issue in condition report 2562192, and the investigation determined that no unauthorized access to the room had occurred.
ATTACHMENT:
SUPPLEMENTARY INFORMATION
KEY POINTS OF CONTACT
Exelon Generation Company Personnel
- M. Massaro, Site Vice President
- P. Navin, Plant Manager
- J. Armstrong, Regulatory Assurance Manager
- D. Baracco, Radiological Engineering Manager
- J. Chizever, Design Engineering Manager
- T. Dombach, Engineer
- D. Dullum, Regulatory Assurance Engineer
- B. Holmes, Radiation Protection Manager
- J. Layton, Mechanical Maintenance Manager
- J. Lucas, Business Support
- J. McClintock, LOR Training Supervisor
- H. McCroy, Radiation Protection Technical Support Manager
- B. Miller, Fire Protection Engineer
- N. Patel, Plant Engineering
- M. Retzer, Outage Manager
- C. Reynolds, MOV Engineer
- W. Reynolds, Engineering Programs Manager
- D. Wheeler, Maintenance Rule Program Engineer
NRC PERSONNEL
- J. Heinly, Senior Resident Inspector
- B. Smith, Resident Inspector
- P. Boguszewski, Reactor Inspector
- C. Graves, Health Physicist
- P. Ott, Reactor Inspector
LIST OF ITEMS OPENED, CLOSED, DISCUSSED, AND UPDATED
Opened/Closed
None
Closed
- 05000278/2015-001 LER Loss of HPCI System Function as a Result of Failed Flow Controller Signal Converter (Section 4OA3)