IR 05000277/2023004

Integrated Inspection Report 05000277/2023004 and 05000278/2023004

ML24043A101
Person / Time
Site:	Peach Bottom
Issue date:	02/12/2024
From:	Jon Greives NRC/RGN-I/DORS
To:	Rhoades D Constellation Energy Generation, Constellation Nuclear
References
IR 2023004
Download: ML24043A101 (1)

Text

February 12, 2024

SUBJECT:

PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 -

INTEGRATED INSPECTION REPORT 05000277/2023004 AND 05000278/2023004

Dear David Rhoades:

On December 31, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Peach Bottom Atomic Power Station, Units 2 and 3. On January 18, 2024, the NRC inspectors discussed the results of this inspection with David Henry, 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. 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 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 (10 CFR) 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely, Jonathan E. Greives, Chief Projects Branch 4 Division of Operating 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: 05000277/2023004 and 05000278/2023004

Enterprise Identifier: I-2023-004- 0041

Licensee: Constellation Energy Generation, LLC

Facility: Peach Bottom Atomic Power Station, Units 2 and 3

Location: Delta, PA 17314

Inspection Dates: October 1, 2023 to December 31, 2023

Inspectors: S. Rutenkroger, Senior Resident Inspector C. Dukehart, Resident Inspector P. Cataldo, Senior Reactor Inspector B. Edwards, Health Physicist P. Finney, Branch Chief J. Kepley, Operations Engineer J. Kulp, Senior Reactor Inspector A. Nugent, Project Engineer

Approved By: Jonathan E. Greives, Chief Projects Branch 4 Division of Operating Reactor Safety

Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated 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

Failure to Follow Scaffolding and Material Staging Requirements Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H.14] - 71111.04 Systems NCV 05000277,05000278/2023004- 01 Conservative Open/Closed Bias The inspectors identified a Green finding and associated non-cited violation (NCV) of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion V, "Instructions,

Procedures, and Drawings," because Constellation personnel did not adequately accomplish scaffold construction, inspection, relocation, and approval in the Unit 3 high-pressure service water (HPSW) pump and B emergency service water (ESW) pump room. Specifically, the inspectors identified scaffolding in contact with safety -related equipment without adequate evaluation and approval.

Required Seismic Clearances Not Maintained Between Drywell Components Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71111.20 Systems NCV 05000278/2023004-02 Open/Closed The inspectors identified a Green finding and associated NCV of 10 CFR Part 50, Appendix B,

Criterion III, "Design Control," because Constellation did not maintain safety-related equipment in a seismically analyzed condition. Specifically, the uni-strut support structure supporting conduits associated with the torus to drywell vacuum breaker position indication was in contact with safety/relief valve (SRV) discharge piping without supporting pipe stress analysis.

Failure to Update Procedures Related to Reopening Main Steam Isolation Valves (MSIVs) for an Offgas System Control Valve Modification Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71152A Systems NCV 05000277/2023004-03 Open/Closed The inspectors identified a self-revealing Green finding and associated NCV of Technical Specification (TS) 5.4.1 (a), Procedures, because Constellation failed to revise system operating and emergency procedures following an offgas system modification. As a result, the station's ability to restore main feedwater as a primary short term heat removal system as well as long term heat removal to the condenser was challenged following a Unit 2 reactor scram and main steam isolation valve (MSIV) isolation in May 2022.

Additional Tracking Items

None.

PLANT STATUS

Unit 2 began the inspection period at rated thermal power (RTP). On November 10, 2023, the unit was down powered to 67 percent for a control rod sequence exchange and main turbine valve exercising and testing. The unit was returned to RTP the following day and remained at or near RTP for the remainder of the inspection period.

Unit 3 began the inspection period in end-of-cycle coastdown. On October 15 and 16, 2023, the unit was down powered and then shutdown for a planned refueling outage (RFO). After completing the refueling, the unit was restarted on October 28, 2023, synchronized to the grid on October 29, 2023, and returned to RTP on October 30, 2023. On October 31, 2023, the unit was down powered to 70 percent for a control rod pattern adjustment and returned to RTP the following day. The unit remained at or near RTP for the remainder of the inspection period.

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 performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed on -site portions of IPs. 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.

71111.04 - Equipment Alignment

Partial Walkdown (IP Section 03.01) (4 Samples)

The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:

(1) Unit 3, 'A' and 'C' core spray on October 4, 2023

(2) Unit common, HPSW systems when cross-connected during Unit 3 bay cleaning on October 19, 2023

(3) Unit 3, 'B' residual heat removal (RHR) system on October 31, 2023

(4) Unit 3, 'A' and 'C' HPSW on November 8 through 16, 2023

71111.05 - Fire Protection

Fire Area Walkdown and Inspection (IP Section 03.01) (8 Samples)

The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:

(1) Unit 2, reactor building (RB), elevation 165, General Area, PF-5J, on October 3, 2023

(2) Unit 3, RB, elevation 165, General Area, PF-13J, on October 4, 2023

(3) Unit common, emergency diesel generator (EDG) building, PF-132, on October 12, 2023

(4) Unit 3, reactor core isolation cooling (RCIC) room, PF-63, on October 18, 2023

(5) Unit 3, RB, elevation 135', General Area, PF-13H(P), on October 19, 2023

(6) Unit 3 RB, elevation 135', General Area, PF-13H / PF-13P, on October 20, 2023

(7) Unit 3, RB drywell entrance, PF-13H, on October 23, 2023

(8) Unit 3, 'B' and 'D' RHR rooms, PF-9 and PF-11, on October 23, 2023

71111.06 - Flood Protection Measures

Flooding (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated internal flooding mitigation protections in the Unit 3 'A' loop of the RHR system while providing the shutdown cooling function on October 21, 2023

71111.08G - Inservice Inspection Activities (BWR)

BWR Inservice Inspection Activities - Non-destructive Examination and Welding Activities (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated boiling water reactor non-destructive testing by reviewing the following examinations from October 17, 2023 through December 22, 2023:

• General Visual Examination of Drywell Interior Moisture Barrier (3R24-IWE-VT-026)

• Manual Ultrasonic Examination of N4D Nozzle To Shell Weld (Hitachi Examination Summary Sheet 003500)

• Manual Ultrasonic Examination of N4C Nozzle Inner Radius (Hitachi Examination Summary Sheet 006150)

• Manual Ultrasonic Examination of Main Steam Pipe to Tee Weld 1-B-6 (P3R24-UT-004)

• General Visual Examination of Drywell Elevation 119 (3R24-IWE-VT-001)

• General Visual Examination of Suppression Chamber Interior Above Waterline (3R24-IWE-VT-003)

• Manual Phased Array Ultrasonic Examination of Pipe Bend to Pipe Weld 10-O-23 DM (Hitachi Examination Summary Report 158350)

• Review of Degraded Class 1 Piping Support Accepted by Evaluation in 1R23 (CR 04457690)

• Enhanced Visual Test (EVT-1) of Jet Pump 6 Riser Elbow to Thermal Sleeve Weld (JP 05-06 RS-1)

71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance

Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (1 Sample)

(1) The inspectors observed and evaluated licensed operator performance in the control room during the planned Unit 3 reactor shutdown on October 15 and 16, 2023, and start-up operations on October 28 and 29, 2023

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) Unit common, the inspectors observed and evaluated licensed operator requalification training in the simulator on November 21, 2023

71111.12 - Maintenance Effectiveness

Maintenance Effectiveness (IP Section 03.01) (1 Sample)

The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:

(1) Unit common, hardened containment vent systems through November 7, 2023

Aging Management (IP Section 03.03) (1 Sample)

The inspectors evaluated the effectiveness of the aging management program for the following SSCs that did not meet their inspection or test acceptance criteria:

(1) Unit common, #3 start-up and emergency auxiliary regulating transformer degraded feeder cable on December 15, 2023

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management (IP Section 03.01) (5 Samples)

The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:

(1) Unit 3, yellow outage risk with B RHR out of service for maintenance, the reactor pressure vessel (RPV) head removed, and prior to flooding up the reactor cavity, on October 16 and 17, 2023

(2) Unit 3, 'E-23' emergency 4kV bus planned outage on October 24, 2023

(3) Unit 3, yellow outage risk during lowered inventory transition period of letdown through tensioning of the RPV head on October 26, 2023

(4) Unit 3, 'B' and 'D' HPSW pump replacements and field modifications on November 6 through 14, 2023

(5) Unit 3, risk-informed completion time package for 'B' and 'D' HPSW pump replacements on November 7, 2023

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 03.01) (1 Sample)

The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:

(1) Unit 2, 'E-1' EDG unable to synchronize to the 'E-12' emergency 4 kV bus during EDG testing due to failed contact on the 'E-12' synchronizing switch on November 28, 2023

71111.18 - Plant Modifications

Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02) (2 Samples)

The inspectors evaluated the following temporary or permanent modifications:

(1) Engineering Change (EC) 0000639599, "Scram Air Header Pressure Control Valve Storage Process Vent Elimination," on October 26, 2023

(2) Unit 3, modifications to the ESW sluice gate motor operator seismic restraint on November 14, 2023

71111.20 - Refueling and Other Outage Activities

Refueling/Other Outage (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated the P3R24 RFO from October 16 to October 29, 2023

71111.24 - Testing and Maintenance of Equipment Important to Risk

The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:

Post-Maintenance Testing (PMT) (IP Section 03.01) (5 Samples)

(1) Unit 3, 'E-23' emergency 4kV bus breaker trip testing following lockout replacement on October 24, 2023

(2) Unit 3, 'B' and 'D' loop RHR test following maintenance on October 26, 2023

(3) Unit 3, high-pressure coolant injection overspeed trip test following maintenance on October 27, 2023

(4) Unit 3, 'A' recirculation pump seal test following replacement on October 27, 2023

(5) Unit 3, control rod scram time testing prior to reactor start-up following refueling and hydraulic control unit maintenance on October 27, 2023

Surveillance Testing (IP Section 03.01) (3 Samples)

(1) Unit common, primary containment isolation system Group III logic system functional testing on November 15, 2023

(2) Unit 2, 'E-1' EDG simulated emergency core cooling system (ECCS) signal auto start with offsite power available and full load test on November 28, 2023

(3) Unit 2, reactor protection system turbine low condenser vacuum instrument functional test on December 14, 2023

Containment Isolation Valve Testing (IP Section 03.01) (1 Sample)

(1) Unit 3, MSIV local leak rate testing on October 18, 2023N

71114.06 - Drill Evaluation

Drill/Training Evolution Observation (IP Section 03.02) (1 Sample)

The inspectors evaluated:

(1) Limited scope emergency preparedness drills conducted on November 30 and December 18,

71124.01 - Radiological Hazard Assessment and Exposure Controls

Radiological Hazard Assessment (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated how the licensee identifies the magnitude and extent of radiation levels and the concentrations and quantities of radioactive materials and how the licensee assesses radiological hazards

Instructions to Workers (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated how the licensee instructs workers on plant-related radiological hazards and the radiation protection requirements intended to protect workers from those hazards

Contamination and Radioactive Material Control (IP Section 03.03) (2 Samples)

The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:

(1) Workers exiting the radiologically controlled area

(2) Workers exiting the Unit 3 drywell

Radiological Hazards Control and Work Coverage (IP Section 03.04) (4 Samples)

The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:

(1) Welding area inside the Unit 3 'C' condenser

(2) Demobilization of work completed inside the Unit 3 'A', 'B', and 'C' condensers

(3) Equipment decontamination on the Unit 3 refuel floor

(4) In-Vessel Visual Inspection and equipment removal from the pool

High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (3 Samples)

The inspectors evaluated licensee controls of the following high radiation areas and very high radiation areas:

(1) Unit 3 drywell entry point

(2) Unit 3 torus filter removal area and transport path of filters

(3) Unit 3 reactor water clean-up receiving pump room entry point

Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section 03.06) (1 Sample)

(1) The inspectors evaluated radiation worker and radiation protection technician performance as it pertains to radiation protection requirements

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification

The inspectors verified licensee performance indicators submittals listed below:

MS05: Safety System Functional Failures (SSFFs) (IP Section 02.04)===

The inspectors verified Constellations performance indicator submittals listed below for the period October 1, 2022 through September 30, 2023:

(1) Unit 2 SSFFS

(2) Unit 3 SSFFS

MS06: Emergency AC Power Systems (IP Section 02.05) (2 Samples)

The inspectors verified Constellations performance indicator submittals listed below for the period October 1, 2022 through September 30, 2023:

(1) Unit 2 Emergency AC Power Systems

(2) Unit 3 Emergency AC Power Systems

OR01: Occupational Exposure Control Effectiveness (IP Section 02.15) (1 Sample)

(1) October 1, 2022 through September 30, 2023

PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences (IP Section 02.16) (1 Sample)

(1) October 1, 2022 through September 30, 2023

===71152A - Annual Follow - up Problem Identification and Resolution

Annual Follow - up of Selected Issues (Section 03.03) (3 Samples)

The inspectors reviewed the licensees implementation of its corrective action program (CAP) related to the following issues:

(1) Unit 2, review of Passport document 4686151-02, Post-Scram Action Reviews, that was completed by the operations department to review and capture lessons learned from the May 2022 scram recovery

(2) Unit 3, review of corrective actions as a result of a through wall pipe leak on the HPSW system associated with issue report (IR) 04699907

(3) Unit common, review of corrective actions as a result of degraded #3 start-up and emergency auxiliary transformer 13.2 kV cable associated with IR 04236320

71152S - Semiannual Trend Problem Identification and Resolution

Semiannual Trend Review (Section 03.02)===

(1) The inspectors conducted a semiannual trend review by evaluating sample issues that occurred in the third and fourth quarters of

INSPECTION RESULTS

Failure to Follow Scaffolding and Material Staging Requirements Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H.14] - 71111.04 Systems NCV 05000277,05000278/2023004- 01 Conservative Open/Closed Bias The inspectors identified a Green finding and associated NCV of 10 CFR Part 50, Appendix B, Criterion V, "Instructions, Procedures and Drawings," because Constellation personnel did not adequately accomplish scaffold construction, inspection, relocation, and approval in the Unit 3 HPSW pump and B ESW pump room. Specifically, the inspectors identified scaffolding in contact with safety - related equipment without adequate evaluation and approval.

Description:

On November 9, 2023, the inspectors identified scaffolding that was not constructed in accordance with Constellation procedures in the safety - related section of the circulating water pump structure. Specifically, scaffolding was in contact with the hand wheel of the B ESW discharge block valve to the 'A/B' cross - tie of the ESW piping. The ESW system is a safety - related system common to both Units 2 and 3, and consists of two 100 percent capacity pumps that supply cooling water to the heat exchangers of the four EDGs and other safety - related systems, such as the oil coolers and room coolers for RHR and core spray.

In addition, portable stairs were in contact with vent piping connected to standpipes associated with the Unit 3 HPSW bay level transmitter. The stairs and scaffold were placed in contact with each other which created a continuous, rigid structure between the HPSW bay water level transmitter standpipes and piping and the ESW system piping. The emergency cooling water system is common to Units 2 and 3 and provides a reliable back - up source of cooling water to the ESW and HPSW systems when the pump structure is isolated from the normal heat sink, Conowingo Pond, such as following a seismic event. The pump structure bay water level instrumentation provides indication which is used by control room operators to make decisions regarding the operation of the emergency cooling water system in such a scenario.

Constellation planned maintenance in the Unit 3 pump room from November 5 to November 17, 2023, on the B and D HPSW system to replace the pumps with a new lower pressure design. However, the A and C HPSW pumps, B ESW pump, and the motor driven fire water pump which are in the same room, were not included in the planned maintenance window, and were intended to remain operable/functional. Prior to the work window, the scaffold was constructed on September 14, 2023, as a free-standing structure.

Constellation determined that workers later moved the scaffold without review and authorization. The portable stairs were staged in the room to facilitate access to valves by operations personnel and allowed to be moved when required, similar to a ladder. However, workers inappropriately moved and stored the stairs in contact with the stand-pipe vent piping and the scaffold.

The inspectors identified that Constellation moved the scaffolding in the room contrary to the scaffold control and installation procedures. MA-MA-796- 024-1001, states that, scaffolds shall not be in contact with nuclear safety-related pipes, valves, equipment, pipe hangers, snubbers, conduit, cable trays, instrumentation, tubing, or duct work, and further requires a minimum of 1 inch of clearance to always be maintained for all scaffolds, whether free-standing or braced, including when relocated. MA-AA-796- 024, Scaffold Installation, Inspection, and Removal, does not allow scaffold users to modify scaffolds. MA-AA-716-026, Station Housekeeping / Material Condition Program, requires unsecured equipment that is taller than it is wide to be located at least two feet greater than its height away from safety-related equipment. Any case in which these criteria are not maintained requires engineering review and approval which was neither requested nor performed.

Corrective Actions: Constellation moved and braced the scaffold in a suitable location and relocated the portable stairs to restore clearance requirements.

Corrective Action References: IR 04716566

Performance Assessment:

Performance Deficiency: Scaffold and portable stairs were not maintained, stored, restrained, and evaluated in accordance with procedures.

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. The inspectors also noted that the performance deficiency was similar to Example 4.a of IMC 0612, Appendix E. Specifically, the issue did not have a pre -approved engineering evaluation to assess seismic impact of the scaffold and stairs in contact with safety-related equipment, and the rigid structure spanning the equipment rendered them subject to seismic induced loads that had not been considered in the original analysis. The equipment included ESW valves and piping and HPSW pump bay water level indication relied upon to respond to initiating events, including seismic events and flooding. An analysis of the rigidity of the scaffold structure in conjunction with a re-analysis of the piping and equipment could potentially resolve the concern. However, such an approach would be a new and different calculation method to resolve the concern, and Constellation resolved the concern by reworking the setup, similar to IMC 0612, Appendix E, Example 3.a.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined this finding to be of very low safety significance (Green) in accordance with Exhibit 2, because the finding is a deficiency affecting the design or qualification of a mitigating SSC, and the SSC maintained its operability or probabilistic risk analysis (PRA)functionality.

Cross-Cutting Aspect: H.14 - Conservative Bias: Individuals use decision making-practices that emphasize prudent choices over those that are simply allowable. A proposed action is determined to be safe in order to proceed, rather than unsafe in order to stop. The inspectors determined that Constellation personnel decided to proceed with moving scaffolding with a non-conservative bias and perceived low risk and did not seek further input or review prior to proceeding.

Enforcement:

Violation: Title 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, states that, Activities affecting quality shall be prescribed by documented instructions, procedures, or drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings. Instructions, procedures, or drawings shall include appropriate quantitative or qualitative acceptance criteria for determining that important activities have been satisfactorily accomplished.

Procedure MA-MA-796- 024-1001 requires that all scaffolds maintain a minimum of 1 inch clearance from safety-related equipment when constructed or relocated and that scaffolds are not in contact with nuclear safety-related equipment.

Contrary to this, from a time after September 14 through November 9, 2023, Constellation personnel did not adequately accomplish scaffold construction, inspection, and approval in the safety-related portion of the circulating water pump structure in accordance with approved scaffold control procedures. Specifically, scaffolding in this room was in direct contact with safety-related equipment.

Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.

Required Seismic Clearances Not Maintained Between Drywell Components Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71111.20 Systems NCV 05000278/2023004 - 02 Open/Closed The inspectors identified a Green finding and associated NCV of 10 CFR Part 50, Appendix B, Criterion III, "Design Control," because Constellation did not maintain safety - related equipment in a seismically analyzed condition. Specifically, the uni - strut su pport structure supporting conduits associated with the torus to drywell vacuum breaker position indication was in contact with SRV discharge piping without supporting pipe stress analysis.

Description:

Peach Bottom Atomic Power Station (PBAPS) has eleven 3 -stage Target Rock SRVs per unit. An SRV provides a pressure relief function or system depressurization at full rated flow with a set pressure range of 900 - 1100 psig. Additionally, five of the eleven SRVs are automatic depressurization system (ADS) valves. The purpose of ADS valves is to rapidly depressurize the RPV to allow low pressure ECCSs to provide core cooling. The primary containment pressure suppression system (PCPSS) provides the suppressio n pool as a heat sink to condense the total amount of steam discharged from the SRVs during transients and design basis events. The SRV discharge piping is designed to limit the SRV discharge pressure to less than 40 percent of the SRV inlet pressure (which can be permitted to be as high as 1375 psig) with a corresponding discharge pressure of 550 psig. The PCPSS also provides vacuum relief valves on the SRV discharge piping. These vacuum relief valves reduce the line reflood level, thereby reducing the internal suppression pool pressure and the loads on the steam piping during subsequent SRV actuations.

During the PBAPS RFO, P3R24, the inspectors identified that the uni-strut support structure supporting conduits associated with torus to drywell vacuum breaker position indication was in contact with SRV discharge piping. The inspectors questioned Constellation personnel whether the condition was previously evaluated and approved. The inspectors reviewed design documents and noted that clearances between SSCs were required to be greater than analyzed displacements to prevent contact under all conditions, including movement from seismic events. Constellation provided information that the piping would move due to thermal expansion since the piping was connected to the main steam piping and expressed that the uni-strut would likely absorb any remaining impact without damaging the piping.

However, the inspectors reviewed the documents and noted that the direction of movement indicated on the drawings from thermal expansion was in the direction of the uni-strut. The inspectors noted that marks on the piping indicated a moving point of contact between the uni-strut and the piping and that the structures and systems were required to be qualified for all modes of plant operation. In addition, the amount of movement calculated by seismic analysis exceeded the movement from thermal expansion. The inspectors observed that the uni-strut was in contact with two different SRV discharge pipes on each side of the uni-strut, creating a rigid connection between the piping. Finally, the anchors of the uni-strut were not analyzed and that potential consequences from failure of the anchors causing the structure and its connected components to be unsupported were not considered or analyzed.

Corrective Actions: Constellation modified the uni-strut structure so that sufficient clearance existed between the uni-strut structure and SRV discharge piping.

Corrective Action References: IR 04712778 and IR 04713069

Performance Assessment:

Performance Deficiency: The uni-strut support structure supporting conduits associated with the torus to drywell vacuum breaker position indication was in contact with SRV discharge piping without supporting pipe stress analysis.

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. The inspectors also noted that the performance deficiency was similar to Example 4.a of IMC 0612, Appendix E. Specifically, the issue did not have an engineering evaluation to assess seismic impact of the rigid connection between the two SRV discharge pipes created by the intervening uni-strut structure. The rigid structure spanning the pipes rendered them subject to seismic induced loads that had not been considered in the original analysis.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The SDP for Findings At-Power. The inspectors determined this finding to be of very low safety significance (Green) in accordance with Exhibit 2, because the finding is a deficiency affecting the design or qualification of a mitigating SSC, and the SSC maintained its operability or PRA functionality.

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.

Enforcement:

Violation: Title 10 CFR Part 50, Appendix B, Criterion III, Design Control, requires, in part, that measures shall be established to assure that applicable regulatory requirements and the design basis for those SSCs to which this appendix applies are correctly translated into specifications, drawings, procedures, and instructions and that deviations from such standards are controlled.

Contrary to the above, a deviation from the design standards was not controlled. Specifically, the design basis requires that SSCs have sufficient clearances to prevent contact under all operation and design basis conditions, including a design basis seismic event. Prior to October 28, 2023, the uni-strut support structure supporting conduits associated with the torus to drywell vacuum breaker position indication was in contact with SRV discharge piping without supporting analysis, including pipe stress analysis, to accept the condition.

Enforcement Action: This violation is being treated as a NCV, consistent with Section 2.3.2 of the Enforcement Policy.

Failure to Update Procedures Related to Reopening MSIVs for an Offgas System Control Valve Modification Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None (NPP) 71152A Systems NCV 05000277/2023004 - 03 Open/Closed The inspectors identified a self-revealing Green finding and associated NCV of TS 5.4.1 (a),

Procedures, because Constellation failed to revise system operating and emergency procedures following an offgas system modification. As a result, the station's ability to restore main feedwater as a primary short term heat removal system as well as long term heat removal to the condenser was challenged following a Unit 2 reactor scram and MSIV isolation in May 2022.

Description:

P BAPS uses steam from the main steam system as a motive force for the Steam Jet Air Ejector Jet Compressor and to preheat the Offgas System Recombiner to remove non-condensable gases from the main condenser. The main steam system includes main steam line drain lines inside and outside of containment designed to equalize pressure across the MSIVs prior to reopening the MSIVs following a steam line isolation to prevent equipment damage. To re-open the MSIVs, the differential pressure across the valves is required to be less than 50 psi d. Procedurally, the inboard MSIVs and the main steam drain valves are opened to equalize the upstream pressure (reactor pressure) with the downstream pressure.

To accomplish this evolution, all steam loads are secured to minimize the pressure differential. Procedure SO 1A.7.A -2, "Main Steam System Recovery Following a Group I Isolation," directs use of SO 1A.7.A-2 COL, "Main Steam System Lineup after a Group I Isolation," which aligns the appropriate valves to equalize pressure around the MSIVs to allow them to be reopened.

In 2011, Constellation changed the way the offgas system was operated to preclude an unwanted system isolation by isolating control valve CV-4018 to the jet compressors and offgas preheaters and manually maintaining pressure with the 2-inch bypass valve (HV-2-8-43039), vice automatically as referenced in Updated Final Safety Analysis Report Section 9.4.4.2.1.

This change to system operation was not reflected in the check off list SO 1A.7.A-2 COL, Main Steam System Lineup after a Group 1 Isolation." As a result, following a Unit 2 reactor scram and MSIV isolation in May 2022, the controller to the recombiner had a steam demand once the MSIV drains were opened to attempt to establish the required differential pressure. With this steam demand present, the required differential pressure could not be established. Since the procedure was inadequate, it required the operators to review all system alignments, recognize the unwanted steam demand and close the manual isolation valve to the offgas system. After resolution of this valve/equipment line-up and securing the steam demand to the offgas train, the required differential pressure was established and the MSIVs were opened.

Corrective Actions: Constellation subsequently added the main steam bypass valves to procedures SO 1A.7.A-2/3 COL, Main Steam System Lineup after a Group I Isolation," and T-221-2/3, "MSIV Bypass."

Corrective Action References: IR 04727290

Performance Assessment:

Performance Deficiency: The inspectors determined that the failure to perform the required procedure changes following modification of the offgas system operation was a failure to meet TS 5.4.1(a) and was reasonably within Constellations ability to foresee and correct and should have been prevented.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Procedure Quality 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 challenge with opening the MSIVs impacted the stations ability to restore main feedwater as a primary short term heat removal system as well as impacting long term heat removal to the condenser.

Significance: The inspectors assessed the significance of the finding using IMC 0609 Appendix A, The SDP for Findings At-Power.

The inspectors determined this finding to be of very low safety significance (i.e., Green) in accordance with Exhibit 2, "Mitigating Systems Screening Questions," by answering "No" to all of the Mitigating SSCs and PRA Functionality questions. Specifically, the crew was able to re-open the MSIVs using operator knowledge of plant conditions. The floor supervisor directed the offgas train steam supply to be isolated based on control room indications of a downstream steam demand.

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.

Enforcement:

Violation: TS 5.4.1(a), Procedures, requires in part, that written procedures shall be established, implemented, and maintained covering the activities referenced in Regulatory Guide (RG) 1.33, Appendix A, November 1972. RG 1.33, Appendix A, Section B.3 requires General Plant Operating Procedures, which include scram recovery.

Procedure SO 1A.7.A-2 COL, Main Steam Recovery Following Group 1 Isolation, includes instructions for opening the MSIVs as part of the scram recovery to allow re-establishing the main condenser as a heat sink and using the steam-driven feed pumps for reactor water level control.

Contrary to the above, from 2011 until August 2022, Constellation personnel did not maintain the procedures for opening MSIVs following an isolation to ensure personnel had sufficient guidance to re-establish the feedwater pumps or the condenser. Specifically, procedure SO 1A.7.A-2 COL, Main Steam Recovery Following Group 1 Isolation, did not contain the guidance to close off the steam demand to valve HV-2-8-43039, which resulted in differential pressure being too high to allow MSIV opening following a Unit 2 reactor scram and MSIV isolation in May 2022.

Enforcement Action: This violation is being treated as an NCV, consistent with Section 2.3.2 of the Enforcement Policy.

Observation: 71152 Problem Identification and Resolution - Operations 71152A Department Self-Assessment The inspectors evaluated an operations department review of the post-scram actions following a May 2022 Scram and MSIV isolation that was documented under Passport item 4686151- 02, "Post-Scram Action Reviews."

The review did not identify any weaknesses or lessons learned. The documents provided an overview of the event and a timeline of actions and stated, There were no gaps identified in operator response to the event.

Even though no gaps or lessons learned were identified, a training request was submitted under TR-220608-006 to request training on MSIV following a Group 1 MSIV isolation and the training request stated, During scram response recovery there were weaknesses identified in crew knowledge and proficiency associated with a group 1 isolation reset and subsequent opening on the main steam lines. No mention was made regarding valve alignments that complicated the MSIV opening nor the specific knowledge and proficiency challenges that would require training for all license personnel. Additionally, no procedure requests were documented in the assessment to correct the error with a valve alignment check off list that did not isolate steam to the jet compressor and offgas recombiner preheater.

Overall, the inspectors determined that the review documented evolutions that the crews performed well, but did not document any procedural inadequacies or knowledge deficiencies that may have challenged the crews performance or provided insight to the need for the requested training.

Observation: Unit Common, Review of Corrective Actions as a Result of 71152A Degraded '3 Start-up' 13.2 kV Cable Associated with Issue Report (IR) 04236320 The inspectors reviewed and assessed Constellation's corrective actions following the identification of degraded 13.2 kV cables associated with the '3 start-up' transformer and switchgear. Constellation identified that multiple cables were degraded following Tan Delta cable testing per the Cable Management Program in April 2019. Tan Delta testing is a method of testing a cables insulation quality. A cable with faulty insulation could cause the circuit to trip, potentially leading to a loss of offsite power. Constellation identified that over 3000 feet of underground cable required replacement due to degrading insulation. The issue was entered into Constellation's CAP as AR 04236320.

Due to the length and current underground route of the installed cables, Constellation determined that the best method for repairing the degrading cables was to install a new run of cables from the north substation to the '3 start-up' switch gear. The new cable path utilized both an underground and overhead route. Constellation determined that the combined underground and overhead route provided a means to simplify future maintenance.

Constellation completed the project in September 2023.

The inspectors reviewed EC documents, work orders, and conducted interviews with maintenance personnel and engineers. The inspectors also completed walkdowns of the cable path prior to, during, and following completion of the project. Additionally, field work and cable testing were observed and evaluated for accuracy. The inspectors did not identify any findings during the inspection.

Observation: Unit 3, Review of Corrective Actions as a Result of a Through Wall 71152A Pipe Leak on the HPSW System Associated with IR 04699907 The inspectors reviewed Constellation's corrective actions following the identification of a through wall pipe leak on the HPSW system that occurred on September 1, 2023. The leak was identified with HPSW in service providing cooling to the RHR heat exchangers with the system in torus cooling mode during a RCIC surveillance test. The HPSW system was declared inoperable, and the section of piping was isolated to facilitate repairs. The issue was entered into Constellations CAP (AR 04699907).

The size of the affected area was determined by ultrasonic testing of the leak location.

Constellation determined that the size of the degraded area was localized enough to restore system integrity by conducting a branch connection weld repair. Constellation later determined that the failure mechanism was due to microbiologically-influenced corrosion (MIC). MIC is pervasive in standby raw water systems, such as HPSW. There is operating experience at PBAPS with MIC that has previously been identified in these systems.

The branch connection weld repair was performed using a 3 weldolet and cap over the leak location. The repair, weld, and inspection requirements all met American Society of Mechanical Engineers code requirements for Class 3 piping. Eight similar piping locations susceptible to MIC were selected for ultrasonic testing across both units and trains of HPSW to determine the extent of condition. These extent of condition actions were scheduled to be complete within one year of the leak. Following repair and inspection of the system, Constellation filled, vented, and pressurized the system to normal system pressure in a PMT and verified no further leaks existed and the system operated as designed.

The inspectors accompanied technicians in the field to observe the performance of non-destructive testing prior to and following repair of the system. The inspectors observed portions of the repair process and PMT from the control room and the leak location.

Additionally, the inspectors reviewed EC documentation, work group evaluations, and previous system trends. The inspectors did not identify any findings during the inspection.

Observation: Semiannual Trend Review by Evaluating Potential Adverse Trends 71152S in the Third and Fourth Quarters of 2023 The inspectors conducted a semiannual trend review by evaluating a sample of issues that occurred in the third and fourth quarters of 2023. During the evaluation, the inspectors verified the issues identified were addressed within the scope of the CAP. The inspectors reviewed health reports and related databases for trends and considered prior issues while performing routine walkdowns and attending the plan of the day meetings. No substantive adverse performance trends or repetitive equipment failures were identified during this time.

However, inspectors noted multiple issues documenting degraded conditions of vibrating traveling screens. Degraded screens can pose a threat to normal plant operations and challenge plant stability by not managing the consequences of river debris and frazil ice. The outer traveling screens were the most affected group of screens. There were multiple outer traveling screens nonfunctional and unavailable during overlapping periods on both units.

Constellation has been prioritizing corrective actions for nonfunctional traveling screens by tracking resolution on the priority work list. The inspectors also observed Plant Health Committee presentations and discussion regarding short and long term planning to address the conditions.

Based on the overall results of the semiannual trend review, the inspectors determined that Constellation identified adverse trends at PBAPS before they could become more significant safety problems. The inspectors continue to monitor the CAP and maintenance effectiveness during routine inspection activities.

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

• On October 26, 2023, the inspectors presented the IP 71124.01 and 71151 exit debrief inspection results to David Henry, Site Vice President, and other members of the licensee staff.

• On January 18, 2024, the inspectors presented the integrated inspection results to David Henry, Site Vice President, and other members of the licensee staff.

THIRD PARTY REVIEWS

Inspectors reviewed Institute on Nuclear Power Operations reports that were issued during the inspection period.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.04 Miscellaneous M-362 P & I Diagram Core Spray Cooling System, Sheet 2 Revision 62

71111.04 Procedures ST-O-014-350-3 Core Spray Loop 'A' Valve Alignment and Filled and Vented Revision 6

Verification

71111.05 Procedures

71111.05 Procedures PF-13H Unit 3 RB Building; North Crd Equipment & West Corridor Revision 10

Elevation 135'-0"

71111.05 Procedures PF-13J Unit 3 RB Bldg., General Area - Elevation 165-0 Revision 3

71111.05 Procedures PF-13P Unit 3 RB Bldg.; South Crd Equipment & East Corridor Revision 10

Elevation 135'-0"

71111.05 Procedures PF-5J Unit 2 RB Bldg., General Area - Elevation 165-0 Revision 6

71111.08G Corrective Action

Documents

71111.08G Corrective Action 04457690

Documents

71111.08G Corrective Action 04714471

Documents

71111.18 Engineering EC 639599 Scram Air Header Pressure Control Value Storage Process 10/23/2023

Changes Elimination

71111.20 Corrective Action AR 04710366

Documents

Resulting from

Inspection

19