IR 05000277/2023040

95001 Inspection Supplemental Report 05000277/2023040 and Follow-Up Assessment Letter

ML23198A050
Person / Time
Site:	Peach Bottom
Issue date:	07/17/2023
From:	Sarah Elkhiamy NRC/RGN-I/DORS
To:	Rhoades D Constellation Energy Generation, Constellation Nuclear
References
IR 2023040
Download: ML23198A050 (1)

Text

July 17, 2023

SUBJECT:

PEACH BOTTOM ATOMIC POWER STATION, UNIT 2 - 95001 INSPECTION SUPPLEMENTAL REPORT 05000277/2023040 AND FOLLOW-UP ASSESSMENT LETTER

Dear David Rhoades:

On June 8, 2023, the U.S. Nuclear Regulatory Commission (NRC) completed a supplemental inspection using inspection procedure (IP) 95001, "Supplemental Inspection Response to Action Matrix Column 2 (Regulatory Response) Inputs. The NRC inspection team discussed the results of this inspection and the implementation of your corrective actions with Ronald DiSabatino, Jr., Plant Manager, and other members of the licensee staff. The results of this inspection are documented in the enclosed report.

The NRC performed this inspection to sufficiently challenge your stations actions in response to a White finding in the Initiating Events cornerstone. The preliminary White finding and Apparent Violation was documented NRC Inspection Report 05000277/2022003 (ML22299A208). The final significance determination of the White finding and notice of violation (NOV) was documented in NRC Inspection Report 05000277/2022090 (ML22314A098). On February 28, 2023, you informed the NRC that your station was ready for the supplemental inspection.

The NRC determined that your staffs evaluation identified the root cause of the White finding.

Specifically, the NRC inspectors determined your staff's root cause analysis identified one root cause and four contributing causes. The root cause was technical human performance breakdowns at all levels of the operating crew allowed the fourth reactor operator and control room supervisor to operate in knowledge-based mode and direct a procedure not appropriate to the circumstances during a high-stress situation. The first contributing cause was shift management failed to ensure a deliberate and focused pace once plant conditions stabilized due to perceived time pressure. The second contributing cause was the shift manager failed to effectively manage members of the crew before and during the event because performance improvement and error reduction tools were not fully implemented to address crew member at-risk behaviors. The third contributing cause was that leadership oversight of performance has not adjusted for changing workforce proficiency, particularly in response to emergent equipment issues and infrequently performed activities. The fourth contributing cause was the decision to use a partial procedure change as a contingency action was justified based on the precedent of past success.

After sufficiently challenging aspects of Constellation's actions in addressing the White performance issue subject of this IP 95001, Supplemental Inspection Response to Action Matrix Column 2 (Regulatory Response) Inputs, the NRC determined that completed or planned corrective actions were adequate, and concluded Constellations actions met the inspection objectives. Therefore, in accordance with the guidance in Inspection Manual Chapter (IMC) 0305, Operating Reactor Assessment Program, the White finding at Peach Bottom Atomic Power Station Unit 2 will not be considered as an Action Matrix input as of the date of the Exit and Regulatory Performance Meeting, June 8, 2023. Additionally, based on the results of this inspection and the NRCs Action Matrix assessment, Peach Bottom Atomic Power Station Unit 2 will be transitioned to the Licensee Response Column (Column 1) of the Action Matrix effective June 8, 2023, considering the absence of additional Action Matrix inputs.

The NRC inspectors documented three general weaknesses in this report. The inspectors identified one general weakness in the area of problem identification and two general weaknesses in the area of causal analysis. The NRC is treating these consistent with NRC Inspection Manual Chapter 0611 guidance.

No findings or violations of more than minor significance were identified during this inspection.

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, Digitally signed by Sarah Sarah H. H. Elkhiamy Date: 2023.07.17 Elkhiamy 10:47:39 -04'00'

Sarah H. Elkhiamy, Acting Chief Projects Branch 4 Division of Operating Reactor Safety Docket No. 05000277 License No. DPR-44

Enclosure:

As stated

Inspection Report

Docket Number: 05000277 License Number: DPR-44 Report Number: 05000277/2023040 Enterprise Identifier: I-2023-040-0005 Licensee: Constellation Energy Generation, LLC Facility: Peach Bottom Atomic Power Station, Unit 2 Location: Delta, PA Inspection Dates: May 15, 2023 to June 8, 2023 Inspectors: J. Dolecki, Senior Resident Inspector (Team Leader)

S. Haney, Senior Project Engineer Approved By: Sarah H. Elkhiamy, Chief Projects Branch 4 Division of Operating Reactor Safety Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) sufficiently challenged aspects of the licensees corrective actions to address a White performance issue at Peach Bottom Atomic Power Station, Unit 2 by performing a supplemental inspection in accordance with inspection procedure (IP) 95001, Supplemental Inspection Response to Action Matrix Column 2 Inputs, and 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.

The inspectors determined that the licensees problem identification, causal analysis, and corrective actions adequately addressed the performance issue that led to the White finding.

List of Findings and Violations

No findings or violations of more than minor significance were identified.

Additional Tracking Items

Type Issue Number Title Report Section Status NOV 05000277/2022003-03 Loss of Reactor Protection 95001 Closed System Power and Unit Scram Due to Operator Error

INSPECTION SCOPES

Inspections were conducted using the appropriate portions of the 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.

OTHER ACTIVITIES

- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL

===95001 - Supplemental Inspection Response to Action Matrix Column 2 (Regulatory Response) Inputs The inspectors reviewed and sufficiently challenged aspects of Constellations problem identification, causal analysis, and corrective actions to ensure the causes of the White performance issue were correctly identified and corrective actions were adequate to promptly and effectively address and preclude repetition. The White finding and related Notice of Violation (NOV) of Title 10 of the Code of Federal Regulations Part 50, Appendix B, Criterion V, Instructions, Procedures and Drawings, was associated with the use of an inappropriate procedure to restart the Unit 2 'A' reactor protection system (RPS) power source which resulted in inadvertently de-energizing both '2A' and '2B' RPS buses, a reactor scram, and Group I primary containment isolation (main steam isolation valve (MSIV) closure). The preliminary White finding and Apparent Violation is documented in NRC Inspection Report 05000277/2022003 dated October 27, 2022 (ADAMS Accession Number ML22299A208). The final significance determination of a White finding and NOV is documented in NRC Inspection Report 05000277/2022090 dated November 28, 2022 (ADAMS Accession Number ML22314A098).

Constellation performed and documented a root cause evaluation in issue report 04500178. The NRC inspectors review of the Peach Bottom White performance issue and the associated assessment are documented below.

Supplemental Inspection Response to Action Matrix Column 2 (Regulatory Response) Inputs

=

(1) From May 15 to June 8, 2023, the inspectors conducted inspection to sufficiently challenge and verify all objectives of the inspection procedure were met.

INSPECTION RESULTS

Problem Identification Assessment 95001 1. Problem Identification a. Identification. On May 16, 2022, Peach Bottom Unit 2 experienced a transient due to grid perturbations which caused a loss of power to the 2A RPS bus and an associated half-scram condition. The White performance issue was self-revealed when the operators used a procedure not appropriate to the circumstances to restart the 2A RPS motor-generator (MG) set though performance of SO 60F.1.A-2, "Reactor Protection System MG Set and Power Distribution System Startup from Dead Bus Condition." Specifically, when the clean, controlled copy of this procedure was performed, instead of the planned, marked-up partial version of this procedure, operators inadvertently de-energized the 2B RPS bus, which resulted in both Unit 2 RPS buses being de-energized, a reactor scram, and associated closure of the MSIVs.

b. Prior Opportunities for Identification.

The inspectors determined the initial root cause evaluation did not fully identify when and how long the White performance issue existed, and whether there were prior opportunities for correction. Specifically, Constellation did not fully evaluate the timeline where the partial procedure was developed and maintained as a contingency action over an extended period of time. In response, Constellation revised the root cause evaluation to include the stations actions to prepare for the offsite source work window in the duration the condition existed. The root cause evaluation revision also captured past offsite source system outage work windows as prior missed opportunities for identification. The inspectors determined the final revision of the root cause evaluation appropriately considered how long the performance issue existed and identified missed opportunities.

c. Consequences and Compliance.

The root cause evaluation documented that the use of a procedure inappropriate for the plants conditions caused the loss of power to RPS, reactor scram and automatic closure of the MSIVs. Based on their review, the inspectors concluded the root cause evaluation, in general, demonstrated an understanding of the significant plant consequences and compliance concerns associated with the White performance issue.

The NRC's risk evaluation of Peach Bottom's White performance issue was documented in NRC Inspection Report 05000277/2022003 dated October 27, 2022 (ADAMS Accession Number ML22299A208).

NRC Assessment:

Based on a review of Constellation's initial root cause evaluation, the inspectors determined that the IP 95001 inspection objectives could not be met. A revision to the root cause evaluation was required to ensure it fully identified when and how long the White performance issue existed and prior opportunities for identification. The inspectors identified the following general weakness and observation:

General Weakness - Prior Opportunities for Identification, Section 1.b:

The inspectors determined Constellation's initial root cause evaluation was primarily and narrowly focused on the actions and performance of the operating crew the day of the event. The inspectors informed Constellation of potential challenges regarding whether the inspectors could meet the IP 95001 inspection objectives during the inspection preparation week. However, inspectors concluded more fact-finding through direct inspection would be needed to make this determination. During the week of the onsite inspection, the inspectors informed Constellation that this inspection requirement could not be met because Constellation did not fully identify when and how long the White performance issue existed and whether there were prior opportunities for identification.

The inspectors determined Constellation did not fully evaluate the actions taken by the remainder of the organization before that crew took the shift or consider the development and implementation of the partial procedure as a contingency action and its use over an extended period of time. The inspectors identified Constellations initial root cause evaluation included instances of prior opportunities for identification that were not appropriately considered in the causal analysis. For example, the root cause evaluation identified ineffective communication of an integrated risk management clock reset that occurred with a different crew approximately two weeks prior to the event because contingency actions for the offsite source system outage window had not been effectively implemented; however, no actions were put in place to ensure effective communication of integrated risk management clock resets going forward. Additionally, the inspectors identified a break down with the offsite source work activity preparation where the contingency actions that included the use of a white paper and the partial procedure were not completed in advance of the work window. The inspectors determined these break downs indicated that the duration of the performance issue existed for longer than what was presented in the initial root cause analysis and could have impacted other operating crews.

Constellation subsequently revised the root cause evaluation to include station preparation for the offsite source work window in the duration the condition existed. The root cause evaluation revision also captured past offsite source system outage work windows as prior missed opportunities for identification.

Observation - Consequences and Compliance, Section 1.c:

The root cause evaluation documented that the use of a procedure inappropriate for the plants conditions caused the loss of power to RPS, reactor scram and automatic closure of the MSIVs. The root cause evaluation documented that the plant operated as designed in response to the loss of RPS power. Per the NRC's risk evaluation of Peach Bottom's White performance issue documented in NRC Inspection Report 05000277/2022003 dated October 27, 2022 (ADAMS Accession Number ML22299A208), the MSIVs closing caused a reactor high-pressure condition that lifted safety relief valves, caused both recirculation pumps to trip, and resulted in the isolation of the main condenser (normal heat sink). The high-pressure coolant injection and reactor core isolation cooling systems were manually started to stabilize and control reactor pressure and level. Based on inspectors' discussions with senior reactor analysts, the risk-significant plant-specific consequences of the White performance issue were associated primarily with the initiating events loss of the normal condenser heat sink via the closure of the MSIVs, inability to use normal high-pressure reactor feedwater pumps, and the inability to use main turbine bypass valves for heat removal. Operators needed to utilize safety relief valves, the high-pressure coolant injection system, and the reactor core isolation cooling system to discharge the bulk of the decay heat to the primary containments torus.

The inspectors noted that Constellation's initial and revised root cause evaluation did not document a review of the timeline following the Unit 2 reactor scram and associated Group I isolation. Per Constellation procedures, the root cause evaluation should review the White performance issue, including the performance deficiency and significant risk-significant contributors that resulted in it being a White finding. The inspectors, with confirmation through discussion with senior reactor analysts, determined that the timeline and potential performance issues following the scram and Group I isolation were not significant risk contributors to the White performance issue and, consequently were not subject to the supplemental inspection objectives. However, based on the on-site inspection, the inspectors concluded that additional NRC review should be performed to investigate the timeline after the White performance issue, especially related to the transient response to address challenges with elevated main steam line differential pressure. As such, the NRC plans to review licensed operator performance in future inspection activities.

This weakness and observation were independently evaluated in accordance with the guidance in IMC 0612, Appendix B, Issue Screening, and Appendix E, Examples of Minor Issues. The inspectors determined the issues were not of more than minor significance and therefore are not subject to enforcement action in accordance with the NRCs Enforcement Policy.

Causal Analysis Assessment 95001

2. Causal Analysis

a. Methodology. Constellation's root cause evaluation utilized a diverse set of techniques in conducting their investigation, including an Event and Causal Factors Chart, Barrier Analysis, Identifying Programmatic or Organizational Contributors, Safety Culture Assessment, Performance Analysis, Organizational Analysis Tool, and Error Precursors and Flawed Defenses.

The inspectors determined the initial root cause evaluation did not perform an effective review of the White performance issue using the Identifying Programmatic or Organizational Contributors methodology. Following the inspectors engagement, Constellation revised the root cause evaluation during the direct inspection period. The final revision captured one root cause and four contributing causes.

• Root cause: Breakdowns in technical human performance (THU) occurred at all levels of the operating crew that allowed the fourth Reactor Operator and Control Room Supervisor to operate in knowledge-based mode and direct a procedure not appropriate to the circumstance during a high-stress situation, resulting in a reactor scram.

• Contributing cause 1 (CC1): Shift management failed to ensure a deliberate and focused pace once plant conditions stabilized due to perceived time pressure.

• Contributing cause 2 (CC2): The Shift Manager failed to effectively manage members of the crew before and during the event. Specifically, performance improvement and error reduction tools were not fully implemented to address crew member at-risk behaviors.

• Contributing cause 3 (CC3): Leadership oversight of performance has not adjusted for changing workforce proficiency, particularly in response to emergent equipment issues and infrequently performed activities, resulting in events.

• Contributing cause 4 (CC4): The decision to use a partial procedure change as a contingency action was justified based on the precedent of past success. Use of a partial procedure in lieu of processing a permanent procedure revision during this event exposed a programmatic weakness in Operations work week preparation expectations.

Contributing cause 4 was newly identified in the root cause revision.

The inspectors determined the final root cause evaluation employed a systematic evidence-based causal analysis to reliably and methodically determine the root and contributing causes of the White performance issue.

b. Level of Detail. The inspectors determined the initial root cause evaluation was not conducted and documented to a level of detail commensurate with the significance and complexity of the White performance issue. Specifically, the inspectors determined potential root and contributing causes were inappropriately ruled out due to assumptions made as a part of the analysis. Inspectors determined Constellations root cause evaluation did not consider the adequacy of programs or process controls since the event appeared to be primarily human performance focused. In response, Constellation revised the root cause evaluation to explicitly capture what programs were reviewed and how Constellation determined they were or were not causal to the event. The inspectors determined that the final revision of the root cause analysis was conducted and documented to a sufficient level of detail commensurate with the safety significance and complexity of the White performance issue.

c. Operating Experience. The inspectors determined that Constellation appropriately considered prior operating experience to identify and prevent similar occurrences.

Constellation searched industry databases and their corrective action program using key words, including partial procedure, temporary change, scram, stop work criteria, and reactor protection system MG sets. Constellation used internal operating experience and reviewed the corrective action program for similar instances. The inspectors noted that as a result of this review, Constellation identified many instances which had similar attributes to those involved in this event. The inspectors determined Constellation adequately captured the operating experience within their root cause evaluation and has created actions to improve the subject procedure, evaluate training material, establish and reinforce technical human performance expectations, and reinforce the need for supervisory oversight.

d. Extent of Condition and

Cause.

The inspectors determined Constellations evaluation appropriately identified the extent of condition and extent of cause of the White performance issue. For extent of condition, Constellations review did not identify other events caused by using procedures inappropriate to the circumstance. Besides the subject partial procedure, at the time of the root cause evaluation, there were no other open partial procedures in place for contingency response by Operations for an extended period of time. Constellation initiated corrective actions to develop procedural requirements for contingency actions requiring department head approval if a temporary change or partial procedure revision is to be used as a contingency action in lieu of creating a standalone procedure that can be performed as written. Constellation also formalized a process to post contingency actions in the control room.

For extent of cause, Constellation reviewed management direction to use a procedure not appropriate for conditions, less than adequate application of human performance and technical human performance tools, less than adequate management administration of excellence plans, and failure to recognize and correct performance improvement processes for proficiency decline. As a result, Constellation, in part, initiated corrective actions to issue an Operations Standing Order which added multiple human performance barriers, directs face to face reinforcement of technical human performance, and increases the number of observations to confirm that these barriers are being appropriately implemented. Upcoming system outage windows on the other startup source have been verified to have adequate mitigating actions in place. Also, shift management reviewed all operations personnel identified as potential Operator Excellence Program candidates.

e. Safety Culture. The inspectors determined the safety culture components referenced in NUREG-2165, Safety Culture Common Language, were appropriately considered during the Constellations evaluation of the root cause, extent of condition, and extent of cause.

NRC Assessment:

Based on a review of Constellation's initial root cause evaluation, the inspectors determined that IP 95001 inspection objectives could not be met. A revision to the root cause evaluation was required to ensure the evaluation correctly performed the Identifying Programmatic or Organizational Contributors analysis and contained the appropriate level of detail. The revised root cause evaluation provided sufficient information for the inspectors to complete the IP 95001 inspection objectives. The inspectors identified the following general weaknesses and observation:

General Weakness - Methodology, Section 2.a:

The inspectors determined the initial revision of the root cause evaluation was not conducted using an adequate application of cause analysis methodology. Specifically, the inspectors determined that because Constellation had left out causation chains, the causal analysis did not yield root- and contributing causes that would preclude repetition of similar conditions. Although the inspectors determined Constellation's techniques were selected appropriately, the inspectors concluded that in some cases the tools were not adequately performed. Because Constellation's initial root cause evaluation was primarily and narrowly focused on the actions and performance of the operating crew the day of the event, potential programmatic or organizational weaknesses were not identified.

PI-AA-125-1001, Root Cause Analysis Manual, states, in part that, All root cause investigations need to use PI-AA-125-1003, Attachment 6, to evaluate Organizational Effectiveness for determining actions to address gaps. This was performed, as required using PI-AA-125-1006, Attachment 16, Identifying Programmatic or Organizational Contributors. The Attachments introduction notes that organizational processes and values (culture) provide the greatest leverage in terms of potential for improvement in human performance and the reduction of plant events. However, although this review should have shifted the root cause teams focus to station processes and programs, the only program mentioned is the Operator Excellence Program, and Constellations root cause evaluation again centered its review on individual errors made by the operating crew. Additionally, the inspectors identified multiple examples within the initial root cause evaluation of deficiencies within programs as a result of using, for example, the Events and Causal Factors Chart and Barrier Analysis that did not lead to further review or associated corrective actions.

Constellation acknowledged that the organizational and programmatic analysis and barrier analysis reviews performed in the root cause evaluation did not adequately document what programs were reviewed to satisfy the inspection procedure objective surrounding identification of causal factors that may be root or contributing causes.

Specifically, Constellation acknowledged that it was not evident in the root cause evaluation what programs were reviewed and how it was determined they were or were not causal to the event. Constellation subsequently revised the root cause evaluation to evaluate additional programmatic or organizational contributors to the White performance issue and identified a new, fourth contributing cause as a result. The inspectors determined that the final revision of the root cause evaluation was generally systematic and suited to identify the root and contributing causes.

General Weakness - Level of Detail, Section 2.b:

The inspectors determined that there was an inadequate level of detail in the initial root cause evaluation, as potential root and contributing causes were inappropriately ruled out due to assumptions made as a part of the analysis. The inspectors determined Constellations initial root cause evaluation did not effectively evaluate fundamental or higher-level problems in the processes for how the partial procedure was developed and controlled. Additionally, Constellations initial root cause evaluation lacked depth because it identified several issues, but those issues were not appropriately understood and evaluated. As examples, inspectors determined Constellation did not effectively challenge the reason why a partial procedure was used instead of a temporary or permanent change, why the communication regarding the reset of the integrated risk management clock approximately two weeks prior was not internalized, why the work week preparation document actions were not fully carried out, or why the RPS alternate feed breaker was not protected. The inspectors also noted the equipment operators did not receive adequate training on RPS transfer, whether in classroom training on the system or during the crews scenario-based training, but this was not explored in the initial root cause evaluation. The initial root cause evaluation showed these examples as barriers that broke down, but inspectors determined Constellation did not appropriately question why these barriers broke down.

The inspectors determined Constellation was biased that there were not fundamental or programmatic weaknesses because there had not been significant issues with partial procedure use in the past. However, it was evident that transient response amplified the vulnerability to error when relying on partial procedures since alarm response and procedural direction would direct non-partial procedure use. Constellation revised the root cause evaluation using additional technical rigor to include further basis on what barriers broke down and why, and to capture an additional contributing cause. Upon review of the final root cause evaluation revision, the inspectors determined the lack of detail was resolved to be a general weakness.

Observation - Safety Culture, Section 2.e:

The inspectors determined the safety culture components referenced in NUREG-2165, Safety Culture Common Language, were initially not clearly documented in Constellations evaluation of the root cause, extent of condition, and extent of cause. The inspectors informed Constellation of potential challenges regarding whether the inspectors could meet this inspection requirement. Specifically, the Safety Culture Assessment documented in the root cause report did not follow the guidance in 17 of PI-AA-125-1006, Safety Culture Assessment. Five cross-cutting aspects were selected, but the associated causes and recommended actions taken to address each selected cross-cutting aspect were not documented in the table as required. Constellation subsequently revised the Safety Culture Assessment to clearly correlate to the five aspects to the root and contributing causes in the root cause evaluation and list what actions address the aspects.

These weaknesses and observation were independently evaluated in accordance with the guidance in IMC 0612, Appendix B, Issue Screening, and Appendix E, Examples of Minor Issues. The inspectors determined that none of these deficiencies constitute issues of more than minor significance and therefore are not subject to enforcement action in accordance with the NRCs Enforcement Policy.

Assessment 95001

3. Corrective Actions

a. Corrective Action to Preclude Repetition (CAPR)1) Completed

(a) Constellation identified the following CAPR for the Root Cause (RC1) associated with Peach Bottom operators using a procedure not appropriate to the circumstances:

i.

Constellation created a new permanent RPS procedure, SO 60F.1B-2(3),

REACTOR PROTECTION SYSTEM MG SET STARTUP FOLLOWING AN RPS MG SET TRIP, to provide more condition specific direction when responding to RPS MG Set trips to facilitate rule-based performance (CAPR 04500178-27).

Constellation reviewed the use of partial procedures for RPS configuration and determined that the historic use of partial procedures warrants the development of a comprehensive, standalone procedure with a fully developed decision structure to support all potential electrical configurations for the RPS. This action will reduce the potential for technical human performance errors in directing field actions for RPS system manipulations. This action will prevent recurrence of this specific event.

(b) Effectiveness Review. The inspectors determined the CAPR developed and implemented by Constellation was appropriate. The inspectors determined that this new permanent procedure would preclude repetition of this specific event related to an RPS MG set trip. In general, the corrective action to preclude repetition identified a corresponding effectiveness review which contained quantitative and qualitative measures of effectiveness. Additionally, the inspectors concluded the actions, owners, and due dates were appropriate and commensurate with the corresponding corrective action to preclude repetition.

b. Other Corrective Actions (CAs)1) Completed

(a) Constellation identified the following corrective actions to address the root cause (RC1):

i.

Interim corrective action to remove the Control Room Supervisor from watch-standing duties and Operations Director to determine remediation requirements (CA 04500178-28).

ii.

Interim corrective action to remove the fourth Reactor Operator from watch-standing duties and Operations Director to determine remediation requirements (CA 04500178-29).

iii.

Interim corrective action for Operations training to include learnings from this event in training including 1) a formal simulator exercise and 2) RPS system review (CA 04500178-40).

(b) Constellation identified the following corrective actions to address contributing cause 1 (CC1):

i.

Shift Operations Superintendent review and reinforce expectations of OP-PB-101-111-1001 Strategies for Successful Transient Mitigation with operators regarding Pace Control during Operations Management Review (CA 04500178-43).

ii.

Develop Shift Manager performance improvement action plan to address the issue of inadequate oversight and leadership behaviors from Shift Managers that has resulted in technical human performance and teamwork breakdowns (CA 04508513-42).

iii.

Remove the Shift Manager from watch-standing duties and Operations Director to determine remediation requirements (CA 04508513-43)

(c) Constellation identified the following corrective action to address contributing cause 2 (CC2):

i.

Each Shift Manager to review with their Senior Reactor Operators the Operator Excellence Program requirements and certify the review to the Shift Operations Superintendent (CA 04500178-49/50/51/52/53).

(d) Constellation identified the following corrective actions to address contributing cause 3 (CC3):

i.

Implement and determine frequency and number of on-shift learning methods, activities, and critiquing, such as (CA 04500178-64):

• Pulse proficiency drills

• Tabletop scenarios / situations/ events / conditions

• Oral diagnostic boards

• You make the call emergency preparedness discussions

• Plant walkdowns, task walkdowns, dynamic learning activities

• Static simulators including glass top simulators

• System/component drawing/print reviews

• Video review of similar evolutions (Shift emergency response organization training videos)

• Use of digital plant resource software

• Equipment operator Just-In-Time Training ii.

Ensure individual Operator Proficiency and Teamwork concerns have appropriate mitigation strategies during Crew / Department Management Review Meetings (CA 04500178-65).

2) Planned

(a) Constellation identified the following corrective action to address contributing cause 2 (CC2):

i.

Revise OP-PB-112-101-1001 SHIFT TURNOVER MEETING PROTOCOL to clarify Contingency Briefing requirements to include participants, ownership, oversight, and details of contingency actions (CA 04508513-51).

(b) Constellation identified the following corrective actions to address contributing cause 4 (CC4):

i.

Revise OP-PB-101-111 PEACH BOTTOM OPERATIONS DEPARTMENT to include a requirement for either creating a new procedure or having Operations Senior Management approve the use of the Partial or Temporary Change process when a contingency action lacks a suitable procedure that can be followed as written (CA 04508513-52).

ii.

Revise AD-PB-101-1003 to require department head approval if a Temporary Change or Partial procedure revision is to be used as a contingency action in lieu of creating a standalone procedure that can be performed as written (CA 04508513-55).

NRC Assessment:

The inspectors determined that Constellation implemented or planned appropriate and timely corrective actions to preclude repetition for a significant condition adverse to quality associated with the White performance issue. Constellation also identified appropriate effectiveness reviews for these corrective actions.

Assessment 95001

4. Conclusion

During supplemental inspection, the inspectors will generally verify licensee performance of issue identification, evaluation, and corrective plans and activities, sufficiently challenging aspects and assessing the adequacy of licensee performance in each of these areas to ensure that the greater-than-green performance issue and their causes have been properly identified and that corrective plans and actions are in place to promptly and effectively address and preclude repetition. Based on a review of the initial root cause evaluation, the inspectors were required to perform an independent evaluation since inspection objective 01.01 to ensure that the root- and contributing causes of individual white performance issues are understood and, by extension, inspection objective 01.02 to ensure that the extent of condition and extent of cause of individual White performance issues are identified could not be met. Specifically, the inspectors determined that the initial root cause evaluation was narrowly focused on the human performance errors made by the operating crew the day of the event, which prevented the NRC inspectors from being able to meet the inspection requirements for

(1) when and how long the performance issue existed and prior opportunities for identification,

(2) using a systematic methodology to identify the root- and contributing causes, and (3)conducting an evaluating to a level of detail commensurate with the significance and complexity of the White performance issue. As a result, Constellation revised the root cause evaluation to, in part, include an additional contributing cause and associated planned corrective actions.

The inspectors determined that the corrective actions have been prioritized commensurate with the significance and regulatory compliance, and corrective actions taken were prompt and effective, and that the NOV related to the supplemental inspection is sufficiently addressed. The inspectors also determined that the final root cause evaluation produced corrective action plans which appear to effectively address and preclude repetition of significant performance issues. Because Constellation was able to resolve the challenges raised by the inspectors prior to the conclusion of the inspection, each of the issues was documented within this report as a general weakness. The inspectors determined that the final root cause evaluation revision contained sufficient information such that Constellation met the objectives of the inspection procedure, and this inspection is, therefore, closed.

EXIT MEETINGS AND DEBRIEFS

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

• On June 8, 2023, the inspectors presented the 95001 supplemental inspection results to Ronald DiSabatino, Jr., Plant Manager, and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

95001 Corrective Action 04500178 Root Cause Investigation Report, U2 Reactor Scram 1

Documents

95001 Corrective Action 04500178-27 Corrective Action to Prevent Recurrence (CAPR): new

Documents procedure to restart the RPS M/G set following a trip

95001 Corrective Action 04502493 4.0 Critique - Grid disturbance and U2 Reactor Scram 05/17/2022

Documents

95001 Corrective Action 04541566 Readiness Assessment- Supplemental Inspection for NRC 01/09/2023

Documents White finding- Unit 2 Reactor Protection System (RPS)

Automatic Scram

95001 Corrective Action 04500178 Root Cause Investigation Report, U2 Reactor Scram 2

Documents

Resulting from

Inspection

95001 Corrective Action 04508513-51 Revise OP-PB-112-101-1001 SHIFT TURNOVER MEETING

Documents PROTOCOL to clarify Contingency Briefing requirements to

Resulting from include participants, ownership, oversight, and details of

Inspection contingency actions

95001 Corrective Action 04508513-52 Revise OP-PB-101-111 "PEACH BOTTOM OPERATIONS

Documents DEPARTMENT" to include a requirement for either creating a

Resulting from new procedure or having Operations Senior Management

Inspection approve the use of the Partial or Temporary Change process

when a contingency action lacks a suitable procedure that

can be followed as written

95001 Corrective Action 04508513-55 Revise AD-PB-101-1003 to require department head

Documents approval if a Temporary Change or Partial procedure revision

Resulting from is to be used as a contingency action in lieu of creating a

Inspection standalone procedure that can be performed as written

95001 Corrective Action 04678294 "Safety Culture Assessment" Documentation Gaps 06/14/2023

Documents

Resulting from

Inspection

95001 Corrective Action 04678892 RPS Scram Root Cause Revisions Required 05/17/2023

Inspection Type Designation Description or Title Revision or

Procedure Date

Documents

Resulting from

Inspection

95001 Procedures AD-AA-101 PROCESSING OF PROCEDURES, T&RMs, AND FORMS 31

95001 Procedures AD-AA-101-F-10 Temporary Procedure Change -Site Approval Form 2

95001 Procedures AD-PB-101-1003 TEMPORARY CHANGES TOAPPROVED DOCUMENTS 15

AND PARTIAL PROCEDURE USE

95001 Procedures HU-AA-101 HUMAN PERFORMANCE TOOLS AND 14

VERIFICATIONPRACTICES

95001 Procedures HU-AA-102 TECHNICAL HUMAN PERFORMANCE PRACTICES 9

95001 Procedures HU-AA-104-101 PROCEDURE USE AND ADHERENCE 7

95001 Procedures HU-AA-1211 PRE-JOB BRIEFINGS 14

95001 Procedures OP-AA-101-111 ROLESAND RESPONSIBILITIES OF ON-SHIFT 13

PERSONNEL

95001 Procedures OP-AA-101-113 OPERATOR FUNDAMENTALS 16

95001 Procedures OP-AA-105-102 NRC ACTIVE LICENSE MAINTENANCE 17

95001 Procedures OP-AA-107 INTEGRATED RISK MANAGEMENT 6

95001 Procedures OP-AA-108-117 PROTECTED EQUIPMENT PROGRAM

95001 Procedures OP-PB-101-111- STRATEGIES FOR SUCCESSFUL TRANSIENT 29

1001 MITIGATION

95001 Procedures OP-PB-112-101- REACTOR OPERATOR SHIFT TURNOVER CHECKLIST 4

1005

95001 Procedures PI-AA-120 ISSUE IDENTIFICATION AND SCREENING PROCESS 13

95001 Procedures PI-AA-125 CORRECTIVE ACTION PROGRAM (CAP) 8

95001 Procedures PI-AA-125-1001 ROOT CAUSE ANALYSIS MANUAL 6

95001 Procedures PI-AA-125-1006 INVESTIGATION TECHNIQUES MANUAL 5

95001 Procedures PI-AA-125-1006 INVESTIGATION TECHNIQUES MANUAL 7

95001 Procedures PI-AA-125-1006, EVENT AND CAUSAL FACTORS CHART 5

95001 Procedures PI-AA-125-1006, BARRIER ANALYSIS 5

95001 Procedures SO 1A.7.A-2 COL MAIN STEAM SYSTEM LINEUP AFTER A GROUP I 2

ISOLATION

Inspection Type Designation Description or Title Revision or

Procedure Date

95001 Procedures SO 1A.7.A-2 COL MAIN STEAM SYSTEM LINEUP AFTER A GROUP I 3

ISOLATION

95001 Procedures SO 60F.1.A-2 REACTOR PROTECTION SYSTEM MGSET AND POWER 11

DISTRIBUTION SYSTEM STARTUP FROM DEAD BUS

CONDITION

95001 Procedures SO 60F.1.B-2 REACTOR PROTECTION SYSTEM MG SET STARTUP 0

FOLLOWING AN RPS MG SET TRIP

16