IR 05000277/2020011
| ML20252A081 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 09/08/2020 |
| From: | Mel Gray Engineering Region 1 Branch 1 |
| To: | Bryan Hanson Exelon Generation Co, Exelon Nuclear |
| Gray M | |
| References | |
| IR 2020011 | |
| Download: ML20252A081 (20) | |
Text
September 8, 2020
SUBJECT:
PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 - DESIGN BASES ASSURANCE INSPECTION (TEAMS) INSPECTION REPORT 05000277/2020011 AND 05000278/2020011
Dear Mr. Hanson:
On July 26, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Peach Bottom Atomic Power Station, Units 2 and 3. On July 31, 2020, the NRC inspectors discussed the results of this inspection with Mr. Matthew Herr, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.
Three findings of very low safety significance (Green) are documented in this report. All of these findings involved violations of NRC requirements. We are treating these violations as non-cited violations (NCVs) consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violations or the significance or severity of the violations documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN:
Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region I; the Director, Office of Enforcement; and the NRC Senior Resident Inspector at Peach Bottom Atomic Power Station, Units 2 and 3.
If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region I; and the NRC Resident Inspector at Peach Bottom Atomic Power Station, Units 2 and 3. This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, X /RA/
Signed by: Melvin K. Gray Mel Gray, Chief Engineering Branch 1 Division of Reactor Safety Docket Nos. 05000277 and 05000278 License Nos. DPR-44 and DPR-56
Enclosure:
As stated
Inspection Report
Docket Numbers: 05000277 and 05000278 License Numbers: DPR-44 and DPR-56 Report Numbers: 05000277/2020011 and 05000278/2020011 Enterprise Identifier: I-2020-011-0005 Licensee: Exelon Generation Company, LLC Facility: Peach Bottom Atomic Power Station, Units 2 and 3 Location: Delta, PA 17314 Inspection Dates: July 13, 2020 to July 31, 2020 Inspectors: F. Arner, Senior Reactor Analyst J. Lilliendahl, Senior Emergency Response Coordinator A. Patel, Senior Reactor Inspector B. Pinson, Reactor Inspector J. Schoppy, Senior Reactor Inspector M. Yeminy, Contractor Approved By: Mel Gray, Chief Engineering Branch 1 Division of Reactor Safety Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a design basis assurance inspection (teams) inspection at Peach Bottom Atomic Power Station, Units 2 and 3, in accordance with the Reactor Oversight Process.
The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
Unit 3 RCIC Turbine Bearing High Oil Level Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [P.1] - 71111.21M Systems NCV 05000278/2020011-01 Identification Open/Closed The team identified a Green finding and associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, because Exelon did not identify and correct a condition adverse to quality. Specifically, Exelon did not identify that the reactor core isolation cooling (RCIC) turbine oil level was above the maximum level mark.
Failure to Increase Safety-Related Battery Testing Frequency Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71111.21M Systems NCV 05000277,05000278/2020011-02 Open/Closed The team identified a finding of very low safety significance (Green) and an associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, because Exelon did not ensure that the test program incorporated the requirements and acceptance limits contained in applicable design documents. Specifically, Exelon failed to incorporate the requirement to increase the safety-related battery testing frequency when the batteries reached 85% of expected life. The impact of temperature derating was not considered when the dates were established for increased battery testing, which resulted in four safety-related batteries exceeding the technical specification (TS) required testing frequency.
480V Breaker Hoists Not Maintained in a Seismically Analyzed Condition Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71111.21M Systems NCV 05000277,05000278/2020011-03 Open/Closed The team identified a Green finding and associated non-cited violation (NCV) of 10 CFR Part 50 Appendix B, Criterion III, Design Control, because Exelon did not maintain equipment in a seismically analyzed condition in accordance with site specific analyses and approved engineering change documents. Specifically, breaker hoists located near 480V switchgear cabinets were not maintained in the seismically analyzed condition that would prevent tipping and potential damage to the safety-related switchgear.
Additional Tracking Items
None.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
Starting on March 20, 2020, in response to the National Emergency declared by the President of the United States on the public health risks of the coronavirus (COVID-19), regional inspectors were directed to begin telework. Regional based inspections were evaluated to determine if all or a portion of the objectives and requirements stated in the IP could be performed remotely. For the inspection documented below portions of the IP were completed remotely as well as on site and all the objectives and requirements for completion of the IP were met.
REACTOR SAFETY
===71111.21M - Design Bases Assurance Inspection (Teams) The team evaluated the following components, permanent modifications, and operating experience during the weeks of July 13 and July 27, 2020.
For the components, the team reviewed the attributes listed in IP 71111.21M, Appendix A, Component Review Attributes, such as those listed below. Specifically, the team evaluated these attributes as per 71111.21M, Appendix B, Component Design Review Considerations and 71111.21M, Appendix C, Component Walkdown Considerations. Specific documents reviewed are listed in the Documents Reviewed section.
Design Review - Risk-Significant/Low Design Margin Components (IP Section 02.02)
=
- (1) Unit 3 Reactor Core Isolation Cooling Pump and Turbine (30P036/30S038)
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Equipment/environmental controls and qualification
- Operator actions
- Design calculations
- Surveillance testing and recent test results
- System and component level performance monitoring
- Equipment protection from fire, flood, and water intrusion or spray
- Heat removal cooling water and ventilation The team used Appendix B guidance for Valves, Pumps, Instrumentation, and As-Built System.
- (2) Unit 3 480 V Bus E434 (LC 30B13)
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Control logic
- Design calculations
- Surveillance testing and recent test results
- Environmental conditions
- Contactor and fuse ratings; Component adequacy for minimum voltage
- Equipment protection from fire, flood, and water intrusion or spray
- Heat removal cooling water and ventilation The team used Appendix B guidance for Instrumentation, Circuit Breakers and Fuses, Cables, Electric Loads, and Motor Control Centers (MCCs).
- (3) Unit 2 125 Vdc Battery 2B (2BD001)
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Control logic
- Design calculations
- Surveillance testing and recent test results
- Equipment protection (sealing of cable and conduits)
- Environmental conditions
- Contactor and fuse ratings; Component adequacy for minimum voltage
- Protection coordination; Load in-rush and full load current
- Range, accuracy, and setpoint of installed instrumentation
- Equipment protection from fire, flood, and water intrusion or spray
- Ventilation for temperature control and hydrogen removal The team used Appendix B guidance for Instrumentation, Circuit Breakers and Fuses, Cables, Electric Loads, and As-Built System.
- (4) E4 Emergency Diesel Generator Fuel Oil Transfer Pump (0DP060)
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Equipment/environmental controls and qualification
- Design calculations
- Surveillance testing and recent test results
- System and component level performance monitoring
- Equipment protection from fire, flood, and water intrusion or spray
- Heat removal cooling water and ventilation The team used Appendix B guidance for Valves, Pumps, Instrumentation, and As-Built System.
- (5) Unit 3 Residual Heat Removal Low Pressure Coolant Injection Valve MO-3-10-025B
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Equipment/environmental controls and qualification
- Operator actions
- Design calculations
- Surveillance testing and recent test results
- Equipment protection (sealing of cable and conduits)
- Equipment protection from fire, flood, and water intrusion or spray The team used Appendix B guidance for Valves, Instrumentation, and As-Built System.
Design Review - Large Early Release Frequency (LERFs) (IP Section 02.02) (1 Sample)
- (1) Unit 3 Residual Heat Removal Drywell Spray Valve MO-3-10-031A
- Material condition and installed configuration (e.g., visual inspection/walkdown)
- Normal, abnormal, and emergency operating procedures
- Consistency among design and licensing bases and other documents/procedures
- System health report, maintenance effectiveness and records, and corrective action history
- Equipment/environmental controls and qualification
- Operator actions
- Design calculations
- Surveillance testing and recent test results
- Equipment protection (sealing of cable and conduits)
- Equipment protection from fire, flood, and water intrusion or spray The team used Appendix B guidance for Valves, Instrumentation, Cables, Electric Loads, and As-Built System.
Modification Review - Permanent Mods (IP Section 02.03) (5 Samples)
- (1) MO-3-23-014 Actuator Upgrade SMB1 to SB1 (EC 0000556030)
- (2) 3 Emergency Aux Transformer 0BX04 Load Side Cable Replacement (EC
===0000627897)
- (3) Install Permanent Stayfull Line for HPCI (EC 0000553768)
- (4) Flange and Support Addition to 20" ESW Pipe in Cardox Room (EC 0000556242)
- (5) Revise Unit 3 Low Condenser Vacuum Scram Setpoint (EC 0000617721)
Review of Operating Experience Issues (IP Section 02.06) ===
- (1) NRC Information Notice 2018-07: Pump/Turbine Bearing Oil Sight Glass Problems
- (2) Curtiss-Wright Part 21- Hex Cap Screws Produced with Pre-Existing Cracks (EN 52852)
- (3) MPR Associates Part 21 - Basler Electric SBSR AVR Card Solder Joints
INSPECTION RESULTS
Unit 3 RCIC Turbine Bearing High Oil Level Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [P.1] - 71111.21M Systems NCV 05000278/2020011-01 Identification Open/Closed The team identified a Green finding and associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, because Exelon did not identify and correct a condition adverse to quality. Specifically, Exelon did not identify that the reactor core isolation cooling (RCIC) turbine oil level was above the maximum level mark.
Description:
In 2011, Exelon personnel established proper RCIC oil levels and scribed the low and high mark on a sight glass (WO 03407356). The work order stated that the procedure to set the levels was followed and determined that the oil level was just touching the trip assembly. As a result, Exelon staff lowered the oil level to obtain the minimum clearance of 1/8 margin from the high level mark to the trip assembly. The team noted that Exelon operators maintain oil levels per procedure MA-AA-734-400, Constant Level Oiler and Sight-Glass Maintenance, which stated in part, Manufacturers instruction manuals should be consulted for information on required levels. The manufacturers instruction manual for the Peach Bottom Unit 3 RCIC turbine is contained in M-1-JJ-122, Nuclear Maintenance Applications Center: Terry Turbine Maintenance Guide, RCIC Application. Section 20 of M-1-JJ-122 describes adequate turbine oil level and stated in part, after establishing the correct oil level, it is critical that the standby, static oil level be maintained near the low-level definition, and in an effort to minimize the potential for oil aeration problems, it is recommended that oil be maintained at or slightly above the minimum level.
On July 15, 2020, during a plant walkdown, the team observed that the Peach Bottom Unit 3 RCIC turbine oil level in the sight glass was above the maximum level mark. In response to this observation, Exelon operations personnel initiated issue report (IR) 04356873 and drained oil from the turbine oil reservoir to establish the proper oil level. The team noted that Exelon staff had not previously identified the high oil level in the corrective action process. Without leaks, RCIC turbine oil levels should remain relatively constant other than when draining oil for samples taken immediately following the quarterly RCIC surveillance test. The team noted that the last surveillance test was completed on June 11, 2020, in which operators did take an oil sample and subsequently added oil. Exelons associated technical evaluation determined that the oil level was likely above the maximum level mark since operators added oil on June 11, 2020. Based on this, the team noted that equipment operators had daily opportunities to identify the degraded condition (high oil level) on their daily rounds between June 11, 2020, and July 15, 2020, when the condition was identified by the team. Operations staff completed a work group evaluation to determine why equipment operators did not identify the high oil level until the problem was identified by NRC inspectors. Operations established actions to re-enforce equipment operator standards in identifying oil level issues.
Exelon engineering staff completed technical evaluation EC 0632213, Unit 3 RCIC Lube Oil Level High Out of Tolerance, Revision 0, to assess past operability for the degraded condition. Per engineerings technical evaluation, industry operating experience indicates out of tolerance high levels may impact the functionality of the RCIC system. With an oil level above the maximum mark, oil can come in contact with the overspeed trip disc and when operating may induce oil aeration (foaming). This condition may result in interruption to bearing drain flow or air entrainment to the lubricating and control oil process piping via the shaft driven oil pump. This could cause erratic turbine control and potentially an unexpected turbine trip. In this case, engineering determined that the as-found level was approximately 1/8 higher than the maximum level mark and that the overspeed trip disc was also located 1/8 higher than the maximum level mark. As a result, the condition provided the potential for oil to contact the overspeed trip disc which could have induced oil aeration during RCIC operation. Engineering staff also stated that there should be at least 1/8 clearance between the oil max level mark and bottom of the overspeed trip disc. Engineerings technical evaluation also stated that the 1/8 clearance is a critical parameter and if that clearance cannot be maintained the overspeed trip disc will be in contact with the oil and can jeopardize the reliability of the system. Engineering staff concluded that RCIC maintained operability due to oil levels decreasing once oil demand increases and oil starts flowing through piping and other components during operation. The team found these conclusions to be reasonable based on the as-found level and system configuration.
Corrective Actions: Exelon staff entered the condition into the corrective action program. Additionally, Exelon staff initiated corrective actions to lower oil level within the band and to enhance operator fundamentals to address not identifying oil levels above the maximum level mark.
Corrective Action References: IR 04356873
Performance Assessment:
Performance Deficiency: Exelons failure to identify and correct turbine oil level above the maximum level mark in accordance with 10 CFR Part 50, Appendix B, Criterion XVI was a performance deficiency. Specifically, Exelon did not identify that the RCIC turbine oil level was above the maximum level mark from June 11, 2020, until the NRC team identified the condition on July 15, 2020.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human Performance attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, with an oil level above the required standby band, the RCIC turbine could exhibit a condition for oil to come in contact with the rotating overspeed trip assembly disc which may induce oil aeration (foaming). This condition may result in interruption to bearing drain flow or air entrainment to the lubricating and control oil process piping via the shaft driven oil pump. This ultimately could cause erratic turbine control with a potential for an unexpected turbine trip and as a result impacting RCIC system reliability during its design basis mission time. Also, this is similar to example 3.g in IMC 0612, Appendix E, in which there was a reasonable doubt of availability, reliability or capability of RCIC when first identified by the NRC team and required an evaluation by Exelon to assure past operability. Specifically, example 3.g(d) states that the issue may be considered more than minor if the remaining margin falls outside the licensees design process acceptance criteria. Unfavorable margin means that had values associated with the as-found condition been used, the licensees design process would not have accepted the modification. The team determined that this example was applicable as when establishing the RCIC oil min/max allowed band in 2011, Exelon staff intentionally reduced the allowed band to provide a 1/8 margin to the bottom of the trip disc assembly as they did not want to accept no margin to the bottom of the trip disc.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The team assessed the significance of the finding using IMC 0609 Appendix A, Significance Determination of Reactor Inspection Findings for At - Power, Exhibit 2, Mitigating Systems Screening Questions. The team determined that this finding was a deficiency affecting the design or qualification of mitigating structures, systems, or components, where the structures, systems, or components maintained their operability or functionality. Therefore, the team determined the finding to be of very low safety significance (Green).
Cross-Cutting Aspect: P.1 - Identification: The organization implements a corrective action program with a low threshold for identifying issues. Individuals identify issues completely, accurately, and in a timely manner in accordance with the program. The finding has a cross-cutting aspect in the area of Problem Identification and Resolution, Identification, because Exelon did not identify the RCIC turbine high oil level condition, accurately, and in a timely manner commensurate with its safety significance. (P.1)
Enforcement:
Violation: 10 CFR Part 50, Appendix B, Criterion XVl, "Corrective Action," requires, in part, that measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and non-conformances are promptly identified and corrected.
Contrary to the above, from June 11, 2020, until July 15, 2020, Exelon did not identify and correct a high out-of-specification oil level on the Unit 3 RCIC turbine.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to Increase Safety-Related Battery Testing Frequency Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71111.21M Systems NCV 05000277,05000278/2020011-02 Open/Closed The team identified a finding of very low safety significance (Green) and an associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, because Exelon did not ensure that the test program incorporated the requirements and acceptance limits contained in applicable design documents. Specifically, Exelon failed to incorporate the requirement to increase the safety-related battery testing frequency when the batteries reached 85% of expected life. The impact of temperature derating was not considered when the dates were established for increased battery testing, which resulted in four safety-related batteries exceeding the technical specification (TS) required testing frequency.
Description:
Peach Bottom Unit 2 and 3 TS Surveillance Requirement (SR) 3.8.6.6 states, Verify battery capacity is greater than or equal to 80% of the manufacturers rating when subjected to a performance discharge test or a modified performance discharge test. This surveillance test is required every 48 months in accordance with the Surveillance Frequency Control Program, and every 24 months when battery has reached 85% of the expected life with capacity greater than or equal to 100% of manufacturers rating.
The team reviewed ST-M-57B-732-2, Unit 2B 125/250 VDC Modified Battery Discharge Performance Test, to assess Exelons process for adjusting the performance test frequency as the 2B battery approached the end of its expected life. The team noted that step 7.2.5 of the procedure listed the date for reaching 85% of the expected life as 17 years (December 2020), which is 85% of the manufacturers service life of 20 years for a battery that is operated at 77 degrees Fahrenheit. Operating lead calcium storage batteries above this temperature results in a reduced expected life below the maximum service life. The team requested documentation to justify using the maximum service life as the expected life since the battery rooms are not always maintained at the optimal temperature.
Exelon staff reviewed historical battery temperatures and calculated an expected life of 16.5 years for the 2B battery which corresponds to approximately 14 years being the 85% of expected life which should have triggered battery testing every 24 months in December 2017. Exelon staff performed an extent-of-condition review and determined that all eight safety-related 125 Vdc batteries were in the increased testing frequency interval; however, Exelon staff was unaware as they had not adequately temperature-derated the batteries expected lives. Based on the installation of the eight safety-related batteries between 2003 and 2005, and battery testing occurring in various outages, Exelon staff's review determined that four of the safety-related batteries (2B, 2D, 3A, and 3C) had missed surveillance tests. The other four batteries (2A, 2C, 3B, and 3D) were beyond 85% of expected life but had a test within the last 24 months.
Exelon personnel entered the battery temperature derating and testing issues into their corrective action program as IRs 4359322, 4359931, 4360265, 4360267, and 4360268.
Operators entered TS SR 3.0.3 for the missed TS surveillance tests. Engineering staff promptly completed PB-SURV-013, Risk Evaluation of Station Battery Discharge Testing, Revision 0, to provide an evaluation of the risk associated with a missed surveillance for the discharge test (SR 3.8.6.6) of station batteries 2B, 2D, 3A, and 3C. Engineering staff determined that based on risk it was acceptable to delay the missed surveillance tests to the next outage or first practical opportunity in accordance with TS SR 3.0.3. Based on engineerings risk evaluation, operators exited TS SR 3.0.3.
The team independently reviewed Exelons associated calculations, risk evaluation, and operability determinations. The team found that the batteries remained operable based upon all batteries having capacities above 100% on the most recent capacity tests and the fact that the batteries are the same design and operate in similar environments. In addition, the team concluded that Exelon Engineerings risk evaluation adequately bounded the risk of deferring the battery testing and did not identify any additional concerns.
Corrective Actions: Exelons short-term corrective actions included entering TS SR 3.0.3, performing a risk assessment to defer testing to the next outage of sufficient duration, and entering the condition into their corrective action program.
Corrective Action References: IRs 4359322, 4359931, 4360265, 4360267, and 4360268
Performance Assessment:
Performance Deficiency: The team determined that failing to increase the safety-related battery testing frequency was a performance deficiency that was reasonably within Exelons ability to foresee and prevent.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Design Control attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the impact of temperature derating was not adequately incorporated into the battery test program to assure that all testing required to demonstrate that the batteries would perform satisfactorily in service was identified and performed. The finding was similar to NRC IMC 0612, Appendix E, Examples of Minor Issues (example 1.b),in that the battery expected life required an increased testing frequency and the test interval was exceeded for four safety-related batteries.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The team assessed the significance of the finding using IMC 0609 Appendix A, Significance Determination of Reactor Inspection Findings for At - Power, Exhibit 2, Mitigating Systems Screening Questions. The team determined that this finding was a deficiency affecting the design or qualification of mitigating structures, systems, or components, where the structures, systems, or components maintained their operability or functionality. Therefore, the team determined the finding to be of very low safety significance (Green).
Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the team determined that the finding did not reflect present licensee performance. Specifically, estimated temperature derating calculations were most recently performed by the system engineer in 2016 and Exelon had last revised the test procedure prior to 2014.
Enforcement:
Violation: 10 CFR Part 50, Appendix B, Criterion XI, Test Control, which states, in part, a test program shall be established to assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents.
Contrary to the above, since December 2017, Exelon did not ensure that the test program incorporated the requirements and acceptance limits contained in applicable design documents. Specifically, Exelon failed to incorporate the requirement to increase the safety-related battery testing frequency when the batteries reached 85% of expected life. The impact of temperature derating was not considered when the dates were established for increased battery testing, which resulted in four safety-related batteries exceeding the TS required testing frequency.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
480V Breaker Hoists Not Maintained in a Seismically Analyzed Condition Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71111.21M Systems NCV 05000277,05000278/2020011-03 Open/Closed The team identified a Green finding and associated non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion III, Design Control, because Exelon did not maintain equipment in a seismically analyzed condition in accordance with site specific analyses and approved engineering change documents. Specifically, breaker hoists located near 480V switchgear cabinets were not maintained in the seismically analyzed condition that would prevent tipping and potential damage to the safety-related switchgear.
Description:
As part of Exelons response to NRC Generic Letter 87-02, the Seismic Qualification Utility Group (SQUG) program was performed for Peach Bottom Atomic Power Station in order to verify the seismic adequacy of equipment. In 1995, an evaluation of load center 30B13 was performed by Exelon staff, and determined that breaker hoists on rollers that were located in the corner of various Unit 3 load center rooms were not restrained in a way that would prevent tipping and potential damage to safety-related equipment. As a result, Exelon staff developed and implemented modification ECR 96-04177 in 1998. The modification implemented breaker hoist restraints in Unit 3 that were designed to prevent the hoists from interacting with the nearby switchgear during a seismic event and possibly causing improper operation or malfunction of the equipment.
During an equipment walkdown on July 17, 2020, the team observed that the breaker hoists were located within their designated storage locations near various Unit 3 480V switchgear cabinets, but could not identify the hoist restraints that were installed as part of ECR 96-04177. The team raised questions regarding the currently installed hoist configuration, and whether the previously installed restraints were still required. Exelon staff documented the question in corrective action IR 4358626. Following an initial evaluation, engineering personnel determined that new hoists of a different design had been purchased and installed in June of 2016, and that the previously installed restraints were not compatible. Additionally, engineering personnel determined that when subjected to design basis seismic forces, the hoists would experience forces large enough to cause them to overturn if not properly restrained. On August 14, 2020, engineering personnel completed EC 632287, Past Operability Evaluation of 480VAC Load Centers from Overturned Breaker Hoists in RX Bldg 165 during a Seismic Event, and concluded that all potentially impacted Unit 2 and Unit 3 480V load centers remained operable and capable of performing their design functions. The team reviewed engineerings past operability evaluation (EC 632287), concluded that it was reasonable, and did not identify any additional concerns.
Corrective Actions: Exelon immediately relocated the breaker hoists to locations away from safety-related equipment and documented the issue in their corrective action program.
Exelon also performed an engineering evaluation and past operability review of the condition.
Inspectors performed walkdowns of the 480V breaker hoists in Unit 2 and Unit 3, and verified that they had been relocated away from safety-related equipment.
Corrective Action References: IR 4358626
Performance Assessment:
Performance Deficiency: The inspectors determined that failing to maintain the 480V breaker hoists in a seismically analyzed condition was a performance deficiency that was within Exelons ability to foresee and correct. Specifically, the breaker hoists located near 480V safety-related switchgear cabinets were not seismically analyzed or maintained in accordance with established engineering seismic analyses.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Design Control attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the initial engineering evaluation determined that the breaker hoists were susceptible to tipping during expected seismic forces, a past operability review was necessary to determine equipment impact, and that a new restraint design would need to be developed and implemented. This issue is also similar to example 3.a in IMC 0612, Appendix E, Examples of Minor Issues, in that there was a reasonable doubt with respect to the seismic qualifications of the breaker hoists, which affected the assurance of availability and reliability of safety-related equipment, and Exelon determined that the original modification would have to be reworked to correctly resolve seismic concerns.
Significance: The team assessed the significance of the finding using IMC 0609 Appendix A, Significance Determination of Reactor Inspection Findings for At - Power, Exhibit 2, Mitigating Systems Screening Questions and Exhibit 4, External Events Screening Questions. The team determined that this finding was a deficiency affecting the design or qualification of mitigating structures, systems, or components, where the structures, systems, or components (480V load centers) maintained their operability or functionality. In addition, the unavailable breaker hoist restraints during a seismic event would not cause a plant trip or an initiating event, would not degrade two or more trains of a multi-train system or function, would not degrade one or more trains of a system that supports a risk significant system or function, and did not involve the total loss of any credited probabilistic risk assessment (PRA)function. Therefore, the team determined the finding to be of very low safety significance (Green).
Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance. Specifically, Exelon removed the original breaker hoists (including seismic restraints) and installed new hoists in June 2016.
Enforcement:
Violation: 10 CFR Part 50, Appendix B, Criterion III, Design Control, requires, in part, that design changes, including field changes, shall be subject to design control measures commensurate with the original design and be approved by the responsible organization.
Contrary to the above, from June 2016 until July 23, 2020, the seismic analyses specific to 480V breaker hoists were not consistent with the installed plant equipment. Specifically, breaker hoists stored near various 480V safety-related switchgear cabinets were not restrained to prevent tipping and potential damage to the safety-related switchgear.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On July 31, 2020, the inspectors presented the design basis assurance inspection (teams) inspection results to Mr. Matthew Herr, Site Vice President and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.21M Calculations 11-00496 Fibrite Limit Switch and Torque Switch for Limitorque 5
Operators
ME-0299 Required TDH of RCIC Pump - 600 gpm Supply at Max 1
RPV Pressure
MO-3-10-025B MIDICALC AC Motor Operated GL 96-05 Gate Valve 8
MO-3-10-031A MIDICALC AC Motor Operated GL 96-05 Gate Valve 6
PE-0017 125/250V DC Class 1E Battery Capacity Analysis and 14A
Distribution System Voltage Analysis
PE-0048 AC MCC Control Circuit Evaluation 8A
PE-0121 Voltage Regulation Study 12
PE-0128 Transformer 3EA Cable Ampacity Evaluation 1
PE-0182 125V DC Voltage Analysis 15A
Corrective Action 00428226
Documents 01089348
01445365
2198972
04001946
04004135
04067820
04146368
04161511
230355
238214
287975
04331990
04352116
Corrective Action 04356871
Documents 04356873
Resulting from 04356898
Inspection 04357089
04357112
04357118
Inspection Type Designation Description or Title Revision or
Procedure Date
04357154
04357159
04357163
04357165
04357197
04358626
04359135
04359146
04359322
04359916
04359931
04360002
04360265
04360267
04360268
Drawings 6280-M-361 Shs. Residual Heat Removal System P & I Diagram 73 & 74
3&4
E-26 Sh. 1 125/250 VDC System, Unit 2 88
E-8 Sh. 1 Single Line Meter and Relay Diagram, Standby Diesel 20
Generators and 4160V Emergency Power System, Unit 2
Engineering 15-00100 MO-3-23-014 Actuator Upgrade SMB1 To SB1 0
Evaluations EC 0627897 3EA Cable Replacement 1
EC 0632213 U3 RCIC Lube Oil Level High Out of Tolerance 0
ECR 0000556242 Flange and Support Addition to 20 ESW Pipe in Cardox dated 5/1/17
Room
ECR PB-96- SQUG - Install Breaker Hoist Restraints dated
04177 12/14/98
Miscellaneous M-1-JJ-122 Terry Turbine Maintenance Guide, RCIC Application 0
ST-M-57B-732-2 Unit 2B 125/250 VDC Modified Battery Discharge performed
Performance Test 11/15/14 &
10/27/16
ST-O-013-300-3 RCIC Pump, Valve, Flow and Unit Cooler Functional and In- performed
Service Test without Vibration Data Collection 3/11/20 &
6/11/20
Inspection Type Designation Description or Title Revision or
Procedure Date
ST-O-013-302-3 RCIC Pump, Valve, Flow and Unit Cooler Functional and In- performed
Service Comprehensive Test 3/18/19
Procedures CC-MA-208-1002 Protective Device Sizing 1
ER-AA-300-150 Cable Condition Monitoring Program 6
MA-AA-734-400 Constant Level Oiler and Sight-Glass Maintenance 2
SO 13.1.B-3 RCIC System Manual Operation 13
SO 13.1.C-3 RCIC System Automatic Initiation Response 8
ST-I-010-100-3 RHR Loop A Logic System Functional Test 25
Work Orders 03407356
04178690
04943976
17