ML23037A830

Independent Safety Committee; Thirty-Second Annual Report on the Safety July 1, 2021 - June 30, 2022, Volume I - Main Report

ML23037A830
Person / Time
Site:	Diablo Canyon
Issue date:	09/28/2022
From:	Budnitz R, Lam P, Peterson P Diablo Canyon Independent Safety Committee
To:	Office of Nuclear Reactor Regulation
References
Download: ML23037A830 (1)

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DIABLO CANYON INDEPENDENT SAFETY COMMITTEE THIRTY-SECOND ANNUAL REPORT ONTHE SAFETY OF DIABLO CANYON NUCLEAR POWER PLANT OPERATIONS July 1, 2021 - June 30, 2022 Volume I - MAIN REPORT Robert J. Budnitz, Chair Per F. Peterson, Vice-Chair Peter Lam, Member Approved: September 28, 2022 The DCISC invites questions and comments on this report Contact the DCISC at the following:

The Diablo Canyon Independent Safety Committee c/o Office of the DCISC Legal Counsel SW 4th & Mission, Suite 2, P.O. Box 4523, Carmel, CA 93921-4523 Telephone: 1-800-439-4688 (Califo rnia Only)

E-Mail : dcsafety@dcisc.org World Wide Web: www.dcisc.org

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DIABLO CANYON INDEPENDENT SAFETY COMMITTEE THIRTY-SECOND ANNUAL REPORT ONTHE SAFETY OF DIABLO CANYON NUCLEAR POWER PLANT OPERATIONS July 1, 2021 - June 30, 2022 Volume I-MAIN REPORT Robert J. Budnitz, Chair Per F. Peterson, Vice-Chair Peter Lam, Member Approved: September 28, 2022 The DCISC invites questions and comments on this report.

Contact the DCISC at the following:

The Diablo Canyon Independent Safety Committee c/o Office of the DCISC Legal Counsel SW 4th & Mission, Suite 2, P.O. Box 4523, Carmel, CA 93921-4523 Telephone: 1-800-439-4688 (California Only)

E-Mail: dcsafety@dcisc.org World Wide Web: www.dcisc.org

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I PREFACE This report covers,the activities of the Diab lo Canyon Independent Safety Committee (DCISC) for the period July 1, 2021 through June 30, 2022. This is the thirty-second annual report of the DCISC.

The report is presented in two volumes.

Volume I includes a report summary (Executive Summary), Conclusions and Concerns, the Committee made no Recommendations during this report period, a brief introduction and history regarding the DCISC, Committee activities, and documents received by the DCISC during the reporting period (Section 1.0), DCISC public meetings (Section 2.0), a review and evaluation of Nuclear Regulatory Commission (NRC) assessments and issues (Section 3.0), Committee Member and Consultant investigation topical summaries (Section 4.0), DCPP performance indicators monitored by the DCISC (Section 5.0), open items being followed by the Committee (Section 6.0),

follow-up of Pacific Gas and Electric (PG&E) actions on previous DCISC recommendations (Section 7.0), input to the Committee by members of the public (Section 8.0). PG&E's response to the Thirty-Second Annual Report (Section 9.0) will be incorporated into the Thirty-Third Annual Report. The conclusions also appear in boldface type throughout the main body of the report with a discussion of the subject involved.

Volume II contains a

list of documents received by the DCISC (Exhibit A), public meeting notices and agendas and minutes (Exhibit B), a DCPP operations summary for the reporting period and organization charts (Exhibit C), full investigation reports by Committee Members and Consultants (Exhibit D), a record of plant tours by the DCISC (Exhibit E), the DCISC Open Items List (Exhibit F), communications and correspondence with members of the public (Exhibit G), the Second Restatement of the Charter for the Diablo Canyon Independent Safety Committee (Exhibit H), Current and past DCISC recommendations and PG&E responses for the previous period (Exhibit I), the DCISC informational brochure (Exhibit J), and a glossary of terms (Exhibit K).

The DCISC invites questions, comments on and requests for copies of this report. Contact the DCISC at the following:

The Diablo Canyon Independent Safety Committee SW 4th & Mission, Suite 2 P.O. Box 4523, Carmel, CA 93921-4523 Telephone: 1-800-439-4688 E-mail: dcsafety@dcisc.org World Wide Web: www.dcisc.org P-1

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-I DIABLO CANYON INDEPENDENT SAFETY COMMITTEE Thirty-Second Annual Report on the Safety of Diablo Canyon Nuclear Power Plant Operations EXECUTIVE

SUMMARY

and CONCLUSIONS and RECOMMENDATIONS History and Introduction The Diablo Canyon Independent Safety Committee (DCISC) was established as part of the June 24, 1988, settlement agreement which arose from the rate proceedings for the Diablo Canyon Nuclear Power Plant (DCPP). The DCISC was formed in late 1989 with the appointments of Committee Members and began formal review activities and meetings on January 1, 1990. The original settlement agreement (D.88-12-083) was terminated by the California Public Utilities Commission (CPUC) in its decision to open the state electricity markets to competition on January 1, 1998; however, under the provisions of the Commission's Decisions 97-05-088, issued on May 21, 1997, and 04-05-055, issued on May 27, 2004, the DCISC has continued to function and fulfill its responsibilities as established under the terms of the 1988 settlement agreement.

The original settlement agreement provided for a three-member Independent Safety Committee for the purpose of "reviewing and assessing the safety of operations of DCPP;" The members serve three-year staggered terms and remain on the DCISC until a new appointment or their reappointment is made. To fill an expired term or a vacancy, the CPUC issues a public notice soliciting applications from interested persons or nominations by others of prospective candidates.

Under the revised process in accordance with the restated charter, candidates are selected by the CPUC from the applications plus the incumbent, if willing to serve.

The candidates must be '*persons with knowledge, background and experience in the field of nuclear power facilities and nuclear safety issues." From the list of candidates, the new or returning member is appointed by the Governor of California, the Attorney General of California, or the Chairperson of the California Energy Commission (CEC), whichever made the original appointment.

On May 27, 2004, the CPUC issued Decision 04-05-055. In its decision, the CPUC changed the nomination procedures by eliminating from the process the participation of PG&E and the Dean of Engineering at the University of California at Berkeley, modified the requirements for membership on the DCISC to add "knowledge and background in nuclear safety issues" to the

'*experience in the field of nuclear power facilities," and modified the DCISC's mandate to require it to undertake public outreach in the community. The Decision concluded that the DCISC should retain the discretion to determine how best to accomplish its mandate, that the DCISC shall otherwise continue to exist and to operate, and that funding through cost-of-service rates should continue. To implement this directive, the DCISC has continued to expand its public outreach as ES-1

described in Section 8.0, Public Input and Outreach, and continues to consider additional outreach activities.

On January 25, 2007, the CPUC issued Decision 07-01-028. The CPUC had previously adopted new practices and expectations for the DCISC without concurrently restating the Committee's charter to reflect the changes. In its decision, the CPUC granted the DCISC application for authority to restate its charter including the incorporation into the Restated Charter of several terms, conditions, changes and clarifications necessitated by, and previously authorized by, the CPUC which govern the composition, responsibilities and operations of the Committee. In its decision, the CPUC found the Restated Charter to be in the public's interest as it reflects the latest authority and obligations of the DCISC. The Committee's application was unopposed.

On June 21, 2016, PG&E announced a Joint Proposal with Friends of the Earth, the Natural Resources Defense Council, Environment California, the International Brotherhood of Electrical Works Local 1245, Coalition of California Utility Employees, and the Alliance for Nuclear Responsibility to retire DCPP at the expirations of the current NRC operating licenses in 2024 (Unit 1) and 2025 (Unit 2).

On August 11, 2016, PG&E filed an Application with the California Public Utilities Commission (CPUC) for approval of the retirement of DCPP, implementation of the Joint Proposal, and for recovery of associated costs through proposed ratemaking. On January 16, 2018, the CPU C issued Decision 18-01-022 (D.18-01-022), which approved PG&E's proposal to retire Diablo Canyon by 2025.

At its October 2019 and February 2020 public meetings, following comments received from members of the public and representatives of certain non-governmental organizations, the DCISC continued its discussion of the issue of a continued role for the Committee to review spent nuclear fuel-related activities and issues after the power plant ceases to generate electricity. At its public meetings on October 23, 2019 and February 12, 2020, the Committee received and considered the proposed amendment of its Restated Charter to provide to a continued role for the DCISC following Diablo Canyon's cessation of electricity generating _operations to review nuclear fuel-related issues and to terminate that review upon completion of the safe transfer of all spent fuel to the ISFSI. Minutes of those public meetings are contained in the Annual Report for 2019-2020 in Volume II, Exhibits 8.3, and B.6.

On September 9, 2021, the CPU C approved Decision 21-09-003 adopting a Settlement Agreement proposed in the 2018 Nuclear Decommissioning Cost Triennial Proceeding to provide for a role for the Committee following Diablo Canyon's cessation of electricity generating operations in accordance with a revised charter to continue in its safety oversight role until all the DCPP spent nuclear fuel has been moved from wet storage to dry storage.

On October 11, 2021, PG&E submitted Advice Letter 6361-E, a Tier-2 Advice Letter for approval by the Commission's Energy Division of the Second Restatement of the Charter for the DCISC.

Advice Letter 6361-E was approved and made effective as of November 10. 2021. A copy of the approved Second Restatement is included in Volume II as Exhibit H. l ES-2 I

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The Committee will continue to monitor and report on safety of operations at Diablo Canyon while the plant operates to generate electricity including reviewing any effect of decommissioning-related activities on those operations and, under a revised charter, after cessation of generation operations until all spent fuel has been transferred from the Spent Fuel Pools to the Independent Spent Fuel Storage Installation.

The Committee Members during this period were as follows:

On October l 0, 2007, Robert J. Budnitz, Ph.D. was appointed by California Attorney General Edmund G. Brown Jr. to a term on the Committee expiring June 30, 2010. On April 15, 2010, Attorney General Brown announced the reappointment of Dr. Budnitz to a second three-year term on the Committee commencing July 1, 2010 through June 30, 2013. On June 27, 2013, the CPUC ratified its President's selection of Dr. Budnitz as one of two candidates for appointment by Attorney General Kamala Harris to serve a three-year term on the DCISC for the period July 1, 2013 to June 30, 2016. During that period, Dr. Budnitz continued to serve as a member of the Committee pending his reappointment or replacement. On July 7, 2016, Attorney General Harris announced the reappointment of Dr. Budnitz to serve a three-year term on the Committee commencing July 1, 2016 through June 30, 2019. On August 14, 2019, California Attorney General Xavier Becerra announced his reappointment of Dr. Robert J. Budnitz to a three-year term on the DCISC beginning on July 1, 2019 and ending on June 30, 2022.

Dr. Budnitz served as DCISC Chair during this report period, July 1, 2021 through June 30, 2022.

On June 3, 2009, Peter Lam, Ph.D., was appointed by Chair Karen Douglas, J.D., of the California Energy Commission (CEC) to a three-year term on the Committee commencing July 1, 2009 through June 30, 2012. On July 12, 2012, CEC Chair Robert B. Weisenmiller, Ph.D., announced his reappointment of Dr. Lam to a second three-year term on the Committee commencing July 1, 2012 through June 30, 2015. Dr. Lam was reappointed by Dr. Weisenmiller to third three-year term on the Committee commencing July 1, 2015 and ending on June 30, 2018, and subsequently on June 6, 2018, Dr. Weisenmiller announced Dr. Lam's appointment to a fourth three-year term on the Committee beginning on July 1, 2018 and ending on June 30, 2021. On June 25, 2021, CEC Chair David Hochschild announced his reappointment of Dr. Lam to a fifth three-year term on the Committee beginning on July 1, 2021 and ending on June 30, 2024.

On July 9, 2008, California Governor Arnold Schwarzenegger announced the appointment of Per F. Peterson, Ph.D., PE, to a three-year term on the Committee through June 30, 2011. Professor Peterson previously served as a Committee member from September 2, 2004, through October 9, 2007. Governor Edmund G. Brown Jr. reappointed Professor Peterson to a term on the Committee commencing July 1, 2011 through June 30, 2014. Professor Peterson was subsequently again reappointed by Governor Brown to a three-year term on the DCISC commencing July 1, 2014 and expiring on June 30, 2017. On October 11, 2017, Governor Brown reappointed Professor Peterson to a three-year term on the Committee commencing July 1, 2017 and expiring June 30, 2020. In February 2021 Governor Newsom reappointed Dr. Peterson to a sixth three-year term commencing July 1, 2020 through June 30, 2023.

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Dr. Peterson served as DCISC Vice-Chair during this report period, July 1, 2021 through June 30, 2022.

Overview of Activities during the Current Period This thirty-first annual report covers the period July 1, 2021 - June 30, 2022. The DCISC held three public meetings on the following dates:

October 19-20, 2021, Avila Beach, CA and remotely by Zoom February 15-16, 2022, Avila Beach, CA and remotely by Zoom June 22-23, 2022, Avila Beach, CA and remotely by Zoom These are described in Section 2.0.

The Committee regularly performs the following activities:

Three two-day public meetings each year as reported above Public Meeting Public Meeting Public Meeting Tours of the Diablo Canyon Nuclear Power Plant with members of the public held whenever logistically feasible in conjunction with the public meetings; however there were no tours during this reporting period because of the COVID-19 restrictions.

Nine fact-finding visits annually by individual Committee Members and Consultants to assess issues, review plant programs and activities, and interview PG&E and other personnel Reviews of technical documents received from PG&E, the Nuclear Regulatory Commission, various state and local agencies, and other interested parties. The DCISC requests, and PG&E routinely provides copies of essentially all relevant documents generated by PG&E, the NRC, and other parties.

Visits from time-to-time by the DCISC Members and legal counsel to offices of the CPUC and appointing officials (the Governor of California, California Attorney General and California Energy Commission) to update them on DCISC activities Use of regular part-time technical consultants to assist the DCISC to perform assessments and reviews Use oflegal counsel to advise the Committee on its activities Use of expert consultants, as needed Technical Consultants & Legal Counsel The Restated Charter provides that the Committee may contract for services including the services of consultants and experts to assist the Committee in its safety review. The DCISC Members are ES-4 I

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assisted in their important work by technical consultants and legal counsel. For this report period those persons were:

Technical Consultant: Mr. R. Ferman Wardell, a Registered Professional Engineer, holds both Bachelor and Master of Science degrees in Nuclear Engineering from North Carolina State University. He is a 54-year veteran of the nuclear power industry, having been directly involved in design, quality assurance, operation and nuclear safety oversight activities for Duke Energy Corporation*s seven nuclear units. He was formerly Executive Assistant to the Chairman and CEO at Duke Energy. Mr. Wardell has been a Consultant to the DCISC since 1992.

Technical Consultant: Mr. Richard D. McWhorter, Jr., holds a Bachelor of Science in Mechanical Engineering from the United States Naval Academy. He is a 35-year veteran of the nuclear power industry. He served for ten years as a division officer and department head in the navy's nuclear submarine program in which he was responsible for the operation of his submarine's nuclear power plant. Mr. McWhorter then served the U.S. Nuclear Regulatory Commission for ten years first as an Operator Licensing Examiner and then as Senior Resident Inspector at North Anna Power Station. He then was employed for two years as a Systems Engineering Manager for Dominion Virginia Power at North Anna Power Station. For ten years, Mr. McWhorter was employed at Old Dominion Electric Cooperative where he served as Vice President of Operations and Asset Management. Mr. McWhorter has been a Consultant to the DCISC since 2016.

Legal Counsel: Robert R. Wellington, Esq. has been Legal Counsel for the DCISC since its organization in 1989. He is a graduate of Stanford University and the University of California (Hastings) Law School. For over 40 years his practice has been limited to representing several cities, regional wastewater and solid waste districts and other public agencies, including the DCISC. He advises the DCISC with regard to its legal and administrative matters.

Legal Counsel Robert Rathie, Esq. has been associated with the Committee through his work with the Wellington Law Offices since 1993. He obtained a bachelor*s degree in Social Science and History from Chico State University in 1972 and served for 15 years in the U.S. Merchant Marine as chief purser on board passenger and freight vessels in foreign trade. He received his Juris Doctor degree from Monterey College of Law in 1993. He is a member of the State Bar of California and the Monterey County Bar Association. He assists Mr. Wellington in advising the DCISC with regard to its legal and administrative matters.

The DCISC issues a report for each reporting year, which runs from July 1 to June 30. The report is approved by the Committee Members at the fall public meeting following the end of the reporting period.

The first six-month interim report and subsequent thirty annual reports covered the periods January 1, 1990 - June 30, 2021. This thirty-first annual report covers the period July 1, 2021 - June 30, 2022.

The technical items covered during its public meetings were selected by the DCISC based on the DCISC's own priorities concerning which technical issues are important to cover. PG&E then responded by providing presentations and experts to participate in the public meetings as requested. The DCISC also occasionally requested presentations on relevant issues from others in addition to presentations by PG&E. The following significant items were reviewed during the three public meetings and nine fact-finding meetings held during this reporting period:

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DCPP Responses to the COVID-19 Pandemic Performance During the Unit 1 23rd Refueling Outage DCPP Joint Proposal DCPP Decommissioning Plan Spent Fuel Storage Technical Issues Status of NRC Performance Indicators Probabilistic Risk Assessment Human Performance Reactivity Management Results of 2021 Operating Plan and Key Elements of the 2022 Operating Plan Nuclear Safety Culture Single Point Vulnerabilities Integrated Risk Management Flow Accelerated Corrosion Radiation Protection Cyber Security Program Unit 2 Main Generator Vibration Issue Feedwater Heater Tube Rupture Issue Reactor Coolant System Safety/Security Interface Emergency Diesel Generators FLEX Equipment Update Emergency Preparedness Capital Project Planning DCPP Employee Retention Plan COVID-19 Experience NRC Matters Committee Discussion of Post-Shutdown Role Matrix and Ad Hoc Decommissioning Consultant Individual Committee Members and consultants reviewed many other items in nine fact-finding visits, inspections, meetings, and tours at DCPP. The DCISC keeps track of past, current and future items for review in its Open Items List (Section 6.0 and Volume II, Exhibit F).

COVID-19 Pandemic During the period of the 32nd Annual Report, the DCISC's operational safety review activities continued and were note significantly by occasional compromises created by the COVID-19 pandemic. During the period of this Annual Report Members and Technical Consultants resumed fact-finding visits to visit the plant in person. During the period of this Annual Report the Committee continued with each of its previously scheduled activities, occasionally using teleconference and web-based applications as required to ensure adherence to social distancing and Diablo Canyon access restriction protocols and guidance provided by the San Luis Obispo ES-6 I

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I Health Officer which were strictly observed at all times. The October 2021 and the February and June 2022 public meetings were all conducted as a hybrid meeting, in person in Avila Beach, California but with a virtual component that allowed participating in real time through a Zoom webinar facilitated by AGP Video. The Committee has investigated the measures taken by Diablo Canyon to protect plant personnel from COVID-19 and to continue the safe operation of the power plant and reports of its investigations are contained in this Annual Report (Exhibits B.3, B.6, B.9, D.3, D.6 and, D.9).

Visits by DCISC Members to California State Agencies DCISC Member Dr. Lam had a remote Zoom meeting on October 19, 2020 with California Energy Commission Chair David Hochschild and others in his office to provide updates on DCISC activities, to discuss agency concerns and comments, and to provide copies of the Committee's Annual Report.

DCISC Member Dr. Budnitz had a remote Zoom meeting on November 13, 2020 with Deputy Attorney General Megan Hey and others in her office to review topics of mutual interest and to update the Attorney General's staff on the Committee's recent activities and topical review.

Public input and questions were received at the public meetings, and by e-mail. Members of the public spoke at each of the three DCISC public meetings held during this reporting period. The DCISC has responded to all of their questions and requests during this period.

Overall Conclusion The DCISC concludes that PG&E operated DCPP safely during the period July 1, 2021 -

June 30, 2022.

Specific Conclusions Based on its activities, the DCISC has the following specific conclusions from the major review topics examined during the current reporting period. (References to sections of this report are shown in parentheses). Conclusions here are based on, but may vary from, information contained in Committee Fact-finding Reports in Exhibit Din Volume 2 of this report.

1. The DCISC received regular reports on the Nuclear Regulatory Commission (NRC)

Performance Indicators, DCPP License Event Reports (LERs) sent to NRC, and NRC Inspection Reports and Enforcement Actions (violations) at each of its Public Meetings as well as copies of these documents throughout the reporting period. The DCISC investigated selected reports at its fact-finding meetings. The number of LE Rs has decreased down to two during this one-year period. This represents good regulatory performance.

The Committee notes that, although the NRC concluded that DCPP operated acceptably, it identified three Non-cited Violations and received two License Event Reports of "very low safety significance." This appears to be an improvement from most previous periods.

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The DCISC will continue to review DCPP's NRC regulatory performance during the next reporting period, paying particular attention to the number and significance of DCPP violations and LERs. (3.0)

2. Shift Manager turnover activities were observed to be formal and effective in transferring information between the off-going and oncoming operations staff. A 0700 Operations Focus Brief was found to be well structured with a large amount of relevant information shared in a concise and professional manner. DCPP's Operator rounds procedure and practices appeared satisfactory, and the Chemistry Program was rated Green (Good) with performance in the first industry quartile. DCPP's corrective actions for past problems in Plant Status Control continued to be effective, and plant status control performance was being sustained at a high level. The Operability Determination program appeared to be designed and implemented satisfactorily, and actions taken in response to an inadvertent addition of boric acid to the Reactor Coolant System appeared appropriate and consistent with its low safety significance. (4.1.3)

3. DCPP Maintenance performance has improved and functions with high performance indicators. ( 4.2.3)

4. The DCPP Engineering organization continues to provide excellent performance in supporting the plant. Staffing is being carefully reduced in planning for cessation of operations in 2025 to not adversely affect the safety of operations. (4.3.3)

5. The DCISC found that human performance events at DCPP were being effectively captured and trended with appropriate corrective actions being initiated. Since September 2020, DCPP had one Human Performance event classified at the highest significance level (Station Level Event) which was good performance. (4.4.3)

6. DCPP Nuclear Safety Culture and Safety Conscious Work Environment appear to be healthy and positive. Employees appear open to reporting concerns in any area of employment. None of the concerns involved nuclear safety. (4.5.3)

7. DCPP's Operating Experience Program was healthy and appeared to be implemented effectively except for a missed opportunity in 2011. A March 23, 2022, meeting of the DCPP Notification Review Team and an April 13, 2022, meeting of the Corrective Action Review Board (CARB) were both conducted efficiently and effectively. DCPP's Benchmarking Program continued to be effectively managed and contributed to the improvement of station performance. (4.6.3)

8. The DCPP Emergency Preparedness Program and Emergency Response Organization appeared to be effective and ready to respond to any plant emergencies, including given restrictions caused by the COVID-19 pandemic. The Emergency Preparedness Exercise was successfully designed and implemented by PG&E, and it ES-8 I

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I demonstrated that DCPP's staff could effectively implement the facility's Emergency Plan. (4.7.3)

9. The DCPP Probabilistic Risk Assessment program contains effective tools in understanding and improving nuclear reactor safety. PG&E has established an effective PRA Program staffed by experienced personnel and utilizes PRA to the full extent in analyzing DCPP and in operating DCPP safely. (4.8.3)

10. Regular nuclear oversight of DCPP by nuclear industry organizations has proved positive for DCPP in reporting positive performance results and by providing helpful input for improved performance in achieving excellence. (4.9.3)

11. The DCPP Radioactive Effluent Release Program and the Radiological Environmental Monitoring Program appeared satisfactory in calculating, monitoring, and measuring radioactivity in the environment surrounding DCPP.

During 2020, there were no abnormal releases of radioactivity or abnormal levels of radioactivity detected. DCPP site operations had no significant radiological impact on the health and safety of the public or the environment, and radioactive releases were far below regulatory limits. DCPP continued to properly maintain and use the MIDAS software system for predicting the magnitude and path of airborne radioactive plumes from the plant in the event of an emergency.

Radiation Protection Department performance during Refueling Outage 2R22 was exceptional, achieving an industry best Collective Radiation Exposure of 10. 7 person-rem for the outage. Radiation Protection Department performance during Refueling Outage 1R23 was very good, achieving a Unit 1 best Collective Radiation Exposure of 18.3 person-rem for the outage. The Radiation Protection Department Excellence Plan was focused on appropriate items, and overall performance of the department was good. (4.10.3)

12. DCPP's Software Quality Assurance Program appeared comprehensive and designed to assure computer software was developed, maintained, operated, and changed in an appropriately controlled fashion. The DCPP Quality Verification Audit Program was being effectively implemented, and the assessment activities of the Quality Verification Department were being effectively performed. (4.11.3)

13. The DCPP nuclear fuel has for many years performed flawlessly with no defects or leakage. Unit 1 has performed without defects since 2011, and Unit 2 since 1991. This is excellent performance. DCPP is designing their fuel for the remaining operating life with lower enrichments and shorter cycles. (4.12.3)

14. DCPP's Equipment Reliability performance indicators overall were Yellow (Needing Improvement) due primarily to vibration issues with the Unit 2 Main Generator.

DCPP continued to work to improve Equipment Reliability, and the trend of Equipment Reliability performance was improving. (4.13.3)

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15. DCPP's Management Observation program was being properly implemented with a focus toward first-line Supervisors observing employee activities in the field and reviewing their observations during bi-weekly departmental Observation Review Meetings. DCPP successfully accomplished most of the objectives contained in its 2021 Operating Plan, and the 2022 Operating Plan contained appropriate focus areas with initiatives and key metrics. (4.14.3)

16. DCPP has dealt effectively with equipment and system problems and is focused on improving system health. DCPP's Plant Health Committee effectively focused on system/component health, and overall system health has improved. (4.15.3)

17. Although the DCISC did not review DCPP Steam Generators during this reporting period, the DCPP Steam Generators (SGs) have been performing well since their replacements in 2008 and 2009, and no problems have been reported. (4.16.3)

18. The DCPP Refueling Outages 2R22 and 1R23 Outage Safety Plans and Safety Schedules appeared comprehensive and effective to prevent the plant safety level from dropping below acceptable safety standards. DCPP's Outage Control Center was observed to be effectively managing Refueling Outage 1R23 activities. DCPP's Refueling Outage 1R23 was successfully performed. All planned scope of work was completed, and performance goals were met except for post-outage power ascension and reliability. (4.17.3)

19. DCPP's Cyber Security Program appears to be effectively managed, and efforts are continuing to ensure that the program is successfully sustained. (4.18.3)

20. The inspections for stress corrosion cracking of DCPP Independent Spent Fuel Storage Installation stainless steel multi-purpose canisters and overpacks were completed with no significant adverse findings. DCPP was appropriately managing the license renewal process and the development of an Aging Management Plan for the Independent Spent Fuel Storage Installation and its existing spent fuel storage system.

DCPP's process for procurement of a new spent fuel storage system by Orano appeared appropriate.

The DCISC planned to continue to review technical information on the new system and its NRC licensing documents as more information becomes available. (4.19.3)

21. DCPP's evaluation of the effects of an earthquake on workplace personnel safety and their evaluation of the applic~bility low temperature Texas event were satisfactory.

(4.20.3)

22. DCPP's fire door repair program was strong and effective in repairing or replacing impaired fire (and other similar safety-related) doors in a reasonable timeframe.

(4.21.3)

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23. The DCISC observed that classroom training on the use of emergency procedures for dealing with a loss of heat sink was well conducted by an instructor who was knowledgeable about the subject and displayed good instruction techniques. Two Licensed Operator Continuing Training simulator session were observed, and the simulator performed as expected. Simulator training activities were well prepared, contained appropriate objectives, and were professionally conducted by the instructors. Operators performed well in responding to simulated off-normal events.

The DCISC observed several inactive Licensed Operators in training and considers DCPP's plan to maintain a high number of inactive Licensed Operators in off-shift positions an excellent approach to reduce the risk from unexpected operator losses.

Learning Services Department overall performance was good, and the Department was appropriately focused on ensuring that staff remaining on site through the cessation of power operations will be adequately qualified. (4.22.3)

24. The DCPP FLEX Program was healthy thanks to tight controls on equipment status, maintenance, testing, and needed corrective actions. All FLEX equipment was in the status of "Operational and In Position." (4.23.3)

25. DCPP's Employee Retention Program was being well managed and generally proceeding as expected.

The station incurred some unplanned losses, but the resultant impacts were being appropriately managed.

Staffing numbers and employee skills continued to be adequate to support safe operations.

DCPP's planning for Decommissioning was proceeding on schedule and with appropriate coordination of the regulatory filings and approvals needed to support a prompt and efficient start to decommissioning work activities shortly after the planned cessation of power operations in 2025. The DCISC continued to work with the Diablo Canyon Decommissioning Engagement Panel to identify areas where the DCISC's mission and activities could support the work of the panel.

DCPP's process for authorizing or cancelling proposed capital projects appeared effective. Selections made to delete projects using this process did not appear to compromise plant operational safety. (4.24.3)

26. DCPP's response to and actions for dealing with effects arising from the COVID-19 pandemic are based on maintaining safe, reliable operations with a healthy staff.

Their initiatives appeared appropriate for handling normal operations as well as potential responses to emergencies. DCPP's COVID-19 actions did not appear to adversely affect operational safety. The regular meetings between DCISC Members and DCPP Officers and Directors continue to be beneficial for both organizations.

(4.25.3)

Concerns ES-11

Concerns are items which, while not necessarily warranting recommendations, need enhanced continuing Committee review and scrutiny, or attention by PG&E. Concerns are monitored more actively and frequently by the Committee than they otherwise would be. DCISC's concerns follow:

PG&E entered into an agreement, the Joint Proposal, to close DCPP at the end of its original operating license (2024 for Unit 1 and 2025 for Unit 2). As a result, in a previous reporting period (2018-2019), the DCISC had specific concerns in the two following areas:

a. Retention of qualified, experienced personnel necessary to operate DCPP at an appropriate level of safety. This remains a concern, although to date the DCISC has concluded that the retention plan has been successful to date and plans are working for assuring that qualified operators are available.

b. Adequate spending on programs and equipment to preserve an appropriate level of operational safety. This remains a concern, although to date the DCISC has concluded that DCPP's decisions on cancelling or postponing projects have been sound, and have not significantly affected nuclear safety.

The Committee notes that in mid-2022, proposals began to be discussed that would allow DCPP to continue to operate past the end of its current NRC license in 2025. The Committee plans to aggressively follow these developments and respond-appropriately.

Recommendations:

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I On April 29, 2022, the CA Governor announced the need to continue DCPP's power operation to help avoid electricity shortages, to terminate the Joint Proposal, which would have ended power operations in 2025, and to permit extension of DCPP operations for five additional years beyond 2025.

Additionally, on September 1, 2022, the CA Legislature passed California Senate Bill 846 (SB 846) as an urgency statute to go into immediate effect reauthorizing continued operation of DCPP until 2030. The following steps would likely follow:

• PG&E expects to submit Civil Nuclear Credit program application to Department of Energy

• PG&E then requests federal (NRC) regulatory approvals needed for license extension and continued operations

• Potential federal legislation This license extension would require reactivation of the NRC license extension review, which normally adds 20 additional years to the plant operating license. NRC's review of DCPP's original license renewal application had proceeded to the point of almost issuing their Safety Evaluation Report, when PG&E requested a halt to NRC review.

The DCISC plans to closely monitor these activities.

SB 846 added Section 712.1 to the California Public Utilities Code.

Subsection (e)(2) of Public Utilities Code Section 712.1 relates to the transmittal of the DCISC's annual reports. Accordingly, the Thirty-Second Annual Report on the Safety of Diablo Canyon Nuclear Power Plant Operations for the period July 1, 2021-June 30, 2022 was transmitted in accordance with the direction provided by Public Utilities Code Section 712.1(e )(2).

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I Diablo Canyon Independent Safety Committee THIRTY-SECOND ANNUAL REPORT ON THE SAFETY OF DIABLO CANYON NUCLEAR POWER PLANT OPERATIONS Section Preface July 1, 2021 - June 30, 2022 Table of Contents - Volume I Executive Summary and Conclusions and Recommendations Table of Contents 1.0 Introduction 1.1 Formation of the Independent Safety Committee 1.2 1.3 1.4 1.5 Appointment of Committee Members DCISC Public Meetings and Plant Tours Committee Member Site Inspection Tours and Fact-finding Meetings 1.4.1 Inspections and Visits by Robert J. Budnitz 1.4.2 Inspections and Visits by Peter Lam 1.4.3 Inspections and Visits by Per F. Peterson 1.4.4 Tours ofDCPP by DCISC Members and Members of the Public during the Period July 1, 2021 -June 30, 2022 Visits by DCISC Members to California State Agencies, Outreach Activities to the Diablo Canyon Decommissioning Engagement Panel, and Outreach Activities to the Diablo Canyon Independent Peer Review Panel 1.5.1 Visits by DCISC Members to California State Agencies 1.5.2 Outreach Activities to the Diablo Canyon Decommissioning Engagement Panel i

P-1 ES-1 1-1 1-1 1-3 1-8 1-9 1-9 1-10 1-10 1-11 1-11.

1-11 1-12

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1.5.3 Outreach Activities to the Diablo Canyon Independent Peer I

Review Panel 1-13 1.6 Retirement of Diab lo Canyon Power Plant at Expiration of its Current I

Operating Licenses, Establishment of a Post-Shutdown Role for the DCISC, and PG&E's Civil Nuclear Credit Program Application 1-14 I

1.7 COVID-19 Pandemic 1-22 I

1.8 Documents Provided to the DCISC 1-22 1.9 Documentation ofDCISC Activities 1-22 I

2.0 Public Meetings 2-1 I

2.1 Public Meetings 2-1 3.0 NRC Assessments and Issues 3-1

.I 3.1 Summary of Licensee Event Reports 3-1 I

3.1.1 Discussion and Required LERs 3-1 I

3.1.2 Special Report LERs 3-2 3.1.3 Voluntary LERs 3-2 I

3.1.4 Reactor Trips Reported in LERs 3-2 I

3.1.5 Other Reports to NRC 3-2 I

3.1.6 LER Trends 3-2 3.1.7 DCISC Evaluation and Conclusions 3-3 I

3.2 NRC Inspection Reports and Enforcement Actions 3-3 I

3.2.1 Discussion 3-3 3.2.2 DCISC Review of Trends of Violations 3-5 I

And NRC-Identified Issues I

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3.2.3 DCISC Evaluation and Conclusions 3-7 I

3.3 NRC Performance Evaluations 3-7 I

3.4 DCISC Meetings with NRC Resident Inspector 3-10 3-12 3.5 DCISC Conclusions and Recommendations I

4.0 Summary of Major DCISC Review Topics I

4.1 Conduct of Operations 4.1-1 4.1.1 Overview and Previous Activities 4.1-1 I

4.1.2 Current Period Activities 4.1-1 I

4.1.3 Conclusions and Recommendations 4.1-5 4.2 Conduct of Maintenance 4.2-1 I

4.2.1 Overview and Previous Activities 4.2-1 I

4.2.2 Current Period Activities 4.2-1 4.2.3 Conclusions and Recommendations 4.2-7 I

4.3 Engineering Program 4.3-1 I

4.3.1 Overview and Previous Activities 4.3-1 4.3.2 Current Period Activities 4.3-1 I

4.3.3 Conclusions and Recommendations 4.3-3 I

4.4 Human Performance 4.4-1 4.4.1 Overview and Previous Activities 4.4-1 I

4.4.2 Current Period Activities 4.4-1 I

4.4.3 Conclusions and Recommendations 4.4-2 4.5 Nuclear Safety Culture and Safety Conscious Work Environment 4.5-1 I

4.5.1 Overview and Previous Activities 4.5-1 I

4.5.2 Current Period Activities 4.5-1 I

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4.5.3 Conclusions and Recommendations 4.5-2 I

4.6 Performance Improvement Processes 4.6-1 4.6.1 Overview and Previous Activities 4.6-2 I

4.6.2 Current Period Activities 4.6-2 I

4.6.3 Conclusions and Recommendations 4.6-4 4.7 Emergency Preparedness 4.7-1 I

4.7.1 Overview and Previous Activities 4.7-1 I

4.7.2 Current Period Activities 4.7-1 4.7.3 Conclusions and Recommendations 4.7-4 I

4.8 Risk Assessment and Management 4.8-1 I

4.8.1 Overview and Previous Activities 4.8-1 4.8.2 Current Period Activities 4.8-1 I

4.8.3 Conclusions and Recommendations 4.8-3 I

4.9 Nuclear Safety Oversight and Review 4.9-1 4.9.1 Overview and Previous Activities 4.9-1 I

4.9.2 Current Period Activities 4.9-2 I

4.9.3 Conclusions and Recommendations 4.9-5 4.10 Radiation Protection 4.10-1 I

4.10.1 Overview and Previous Activities 4.10-2 I

4.10.2 Current Period Activities 4.10-2 4.10.3 Conclusions and Recommendations 4.10-5 I

4.11 Quality Programs 4.11-1 I

4.11.1 Overview and Previous Activities 4.11-1 I

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4.11.2 Current Period Activities 4.11-1 I

4.11.3 Conclusions and Recommendations 4.11-5 I

4.12 Nuclear Fuel Performance/Fuel Cycles/Storage 4.12-1 4.12.1 Overview and Previous Activities 4.12-1 I

4.12.2 Current Period Activities 4.12-1 I

4.12.3 Conclusions and Recommendations 4.12-2 4.13 Equipment Reliability 4.13-1 I

4.13.1 Overview and Previous Activities 4.13-1 I

4.13.2 Current Period Activities 4.13-1 4.13.3 Conclusions and Recommendations 4.13-2 I

4.14 Organizational Effectiveness & Organizational Development 4.14-1 I

4.14.1 Overview and Previous Activities 4.14-1 4.14.2 Current Period Activities 4.14-1 I

4.14.3 Conclusions and Recommendations 4.14-3 I

4.15 System and Equipment Performance/Problems 4.15-1 4.15.1 Overview and Previous Activities 4.15-1 I

4.15.2 Current Period Activities 4.15-1 I

4.15.3 Conclusions and Recommendations 4.15-19 4.16 Steam Generator Performance 4.16-1 I

4.16.1 Overview and Previous Activities 4.16-1 I

4.16.2 Current Period Activities 4.16-1 4.16.3 Conclusions and Recommendations 4.16-1 I

4.17 Outage Management 4.17-1 I

4.17.1 Overview and Previous Activities 4.17-1 I

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4.17.2 Current Period Activities 4.17-2 I

4.17.3 Conclusions and Recommendations 4.17-9 4.18 Plant Safety/Security Interface 4.18-1 I

4.18.1 Overview and Previous Activities 4.18-1 I

4.18-1 4.18.2 Current Period Activities 4.18.3 Conclusions and Recommendations 4.18-2 I

4.19 Independent Spent Fuel Storage Installation 4.19-1 I

4.19.1 Overview and Previous Activities 4.19-1 4.19.2 Current Period Activities 4.19-2 I

4.19.3 Conclusions and Recommendations 4.19-9 I

4.20 Seismic, Tsunami and Other External Events 4.20-1 4.20.1 Overview and Previous Activities 4.20-1 I

4.20.2 Current Period Activities 4.20-1 I

4.20.3 Conclusions and Recommendations 4.20-2 4.21 Fire Protection 4.21-1 I

4.21.1 Overview and Previous Activities 4.21-1 I

4.21.2 Current Period Activities 4.21-1 4.21.3 Conclusions and Recommendations 4.21-3 I

4.22 Leaming and Development Programs 4.22-1 I

4.22.1 Overview and Previous Activities 4.22-1 4.22.2 Current Period Activities 4.22-1 I

4.22.3 Conclusions and Recommendations 4.22-4 I

4.23 Nuclear Regulatory Commission Items 4.23-1 I

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I 5.0 6.0 7.0 8.0 9.0 4.23.1 Overview and Previous Activities 4.23.2 Current Period Activities 4.23.3 Conclusions and Recommendations 4.24 Beyond Design Basis Accidents/Fukushima Lessons 4.24.1 Overview and Previous Activities 4.24.2 Current Period Activities 4.24.3 Conclusions and Recommendations 4.25 Other DCISC Reviews 4.26.1 Overviewand Previous Activities 4.26.2 Current Period Activities 4.26.3 Conclusions and Recommendations DCISC Performance Indicators DCISC Open. Items List PG&E Actions on Previous DCISC Report Recommendations Public Outreach 8.1 Telephone Calls and E-mails Received by the DCISC 8.2 DCISC Internet - Worldwide Web Activity 8.3 8.4 8.5 Comments Received at DCISC Public Meetings DCISC Public Tours ofDCPP DCISC Evaluation PG&E Response to DCISC Recommendations

[To be incorporated into the 33rd Annual Report]

vii 4.23-1 4.23-2 4.23-3 4.24-1 4.24-1 4.24-1 4.24-8 4.25-1 4.25-1 4.25-1 4.25-3 5-1 6-1 7-1 8-1 8-1 8-2 8-3 8-4 8-4 9-1

I Volume II - EXHIBITS I

Exhibits Responsibility I

A.

Documents Received By the DCISC A-1 I

B.

DCISC Public Meeting Notices, Agendas and Reports B-1 B.l Notice of October 19-20, 2021 Public Meeting B.1-1 I

B.2 Agenda for October 19-20, 2021 Public Meeting B.2-1 I

B.3 Minutes of October 19-20, 2021 Public Meeting B.3-1 B.4 Notice of February 15-16, 2022 Public Meetings B.4-1 I

B.5 B.5-lAgenda for February 15-16, 2022 Public Meetings B.5-1 I

B.6 Minutes of February 15-16, 2022 Public Meetings B.6-1 B.7 Notice of June 22-23, 2022 Public Meetings B.7-1 I

B.8

. Agenda for June 22-23, 2022 Public Meetings B.8-1 I

B.9 Minutes of June 22-23, 2022 Public Meetings B.9-1 B.10 DCISC Service Mailing List B.10-1 I

C.

Diablo Canyon Operations C-1 I

1.0 PG&E/DCPP Organization C-2 2.0 Summary of Diablo Canyon Operations C-2 I

2.0.1 Capacity Factor C-2 I

2.0.2 Refueling Outages C-3 2.0.3 Collective Radiation Dose Equivalent Exposure C-4 I

2.0.4 Unplanned Reactor Trips C-4 I

2.0.5 Unplanned Safety System Actuations C-4 I

2.0.6 Chemistry Effectiveness Indicator (CEI)

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2.0.7 Fuel Reliability C-5 I

D.

DCISC Reports on Fact-finding Meetings D-1 I

D.l Report on Fact Finding Meeting at DCPP on July 14-15, 2021 D.1-1 1.0 Summary D.1-1 2.0 Introduction D.1-1 I

3.0 Discussion D.1-2 3.1. Observation of Operations Turnover and Focus Meeting D.1-2 3.2. Emergency Preparedness Update D.1-4 I

3.3. Meet with NRC Resident Inspector D.1-6 3.4. Annual Radioactive Effluent Release Report & Annual D.1-7 Radioactive Environmental Operating Report I

3.5. Lessons Learned from Texas Extreme Weather Event D.1-10 3.6. Meet with DCPP Officer D.1-11 3.7. Program for Managing Changes Under 1 0CFR50.59 D.1-11 I

3.8. Management Observation Program D.1-13 3.9. Emergency Diesel Generators D.1-14 3.10. Plant Tour D.1-16 I

3.11. Refueling Outage 2R22 Safety Plan D.1-19 3.12. Observe NSOC Exit Meeting D.1-22 3.13. Radiation Protection Department Update D.1-23 I

4.0 Conclusions D.1-25 5.0 Recommendations D.1-26 6.0 References D.1-26 I

D.2 Report on Fact Finding Meeting at DCPP on August 18-19, 2021 D.2-1 1.0 Summary D.2-1 I

2.0 Introduction D.2-2 3.0 Discussion D.2-2 3.1. Observe Plant Health Committee (remote)

D.2-2 I

3.2. DCISC Member Meet with Jim Welsch, Chief Nuclear D.2-4 Officer (remote) 3.3. DCPP Safety Culture and DCPP Safety Conscious Work D.2-4 I

Environment (remote) 3.4. Meet with Two NRC Resident Inspectors D.2-6 3.5. Institute of Nuclear Power Operations (INPO) Update and D.2-7 I

INPO Mid-Cycle Evaluation 3.6. Intake Structure Concrete Inspection Update and Tour D.2-8 3.7. Software Quality Assurance D.2-9 I

3.8. Chemistry Update D.2-11 3.9. Reactor Coolant System Health D.2-14 4.0 Conclusions D.2-18 I

5.0 Recommendations D.2-19 6.0 References D.2-19 I

D.3 Report on Fact Finding Meeting at DCPP on September 13-15, 2021 D.3-1 I

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I 1.0 Summary D.3-1 I

2.0 Introduction D.3-1 I

3.0 Discussion D.3-2 3.1. Probabilistic Risk Assessment Program D.3-2 3.2. Staffing, Retention and Attrition Update D.3-4 I

3.3. Meet with DCPP Officer D.3-5 3.4. COVID-19 Pandemic Response Update D.3-6 3.5. Cause Evaluation for Failed Auxiliary Saltwater Pump D.3-6 I

3.6. Equipment Reliability Process D.3-7 3.7. Meet with NRC Resident Inspector D.3-8 3.8. Root Cause Evaluation for Unit 2 Main Generator Failures D.3-9 I

3.9. Cybersecurity Program D.3-12 3.10. Auxiliary Feedwater System D.3-13 3.11. Plant Tour D.3-15 I

3.12. Emergency Preparedness Exercise Observation D.3-15 4.0 Conclusions D.3-18 5.0 Recommendations D.3-19 I

6.0 References D.3-19 D.4 Report on Fact-finding Meeting at DCPP November 16-17, 2021 D.4-1 I

1.0 Summary D.4-1 2.0 Introduction D.4-1 3.0 Discussion D.4-2 I

3.1. Observe Licensed Operator Training - Loss of Heat Sink D.4-2 3.2. Independent Spent Fuel Storage Installation Cask Inspection D.4-3 Results I

3.3. Digital Systems Update D.4-5 3.4. Meeting with NRC Resident Inspectors D.4-6 3.5. Feedwater Heater Tube Failure and Forced Reactor D.4-7 I

Shutdowns 3.6. Operating Experience Program Update D.4-7 3.7. Observe Plant Health Committee (remote)

D.4-9 I

3.8. Observe Simulator Training on Anticipated Transient D.4-11 without Scram 3.9. NRC Ultimate Heat Sink Inspection Results D.4-12 I

3.10. Meeting with DCPP Officer D.4-13 4.0 Conclusions D.4-13 5.0 Recommendations D.4-14 I

6.0 References D.4-14 D.5 Report on Fact-Finding Meeting at DCPP on December 7-8, 2021 D.5-1 I

1.0 Summary D.5-1 2.0 Introduction D.5-1 3.0 Discussion D.5-2 I

3.1.

Root Cause Evaluation for Failed Auxiliary Saltwater D.5-2 Pump Motor I

3.2.

Transmission System D.5-3 X

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I D.6 D.7 4.0 5.0 6.0 3.3.

Meet with Nuclear Regulatory Commission (NRC)

Acting Senior Resident Inspector 3.4.

Trends in Plant Status Control Events 3.5.

Crane Program 3.6.

Plant Tour 3.7.

Observe Simulator Training Class 3.8.

Emergency Diesel Generator System Follow-up Items 3.9.

Plant Health Committee Meeting 3.10. Staffing, Retention and Attrition Update 3.11. Meteorological Information and Dose Assessment System 3.12. Meet with DCPP Officer Conclusions Recommendations References Report on Fact Finding Meeting at DCPP on January 11-12, 2022 1.0 Summary 2.0 Introduction 3.0 Discussion 3.1.

Meet with DCPP Officer Maureen Zawalick 3.2.

Review Operator Rounds Procedures and Experience 3.3.

Independent Spent Fuel Storage Installation Cask Inspections 3.4.

Meet with Acting NRC Senior Resident Inspector 3.5.

COVID-19 Update 3.6.

Refueling Equipment Health 3.7.

Fire Doors and Door Life Management 3.8.

Observe Plant Health Committee Meeting 3.9.

Meet with DCPP Officer Adam Peck 3.10. Single Point Vulnerabilities 3.11. Operability Determination Program 3.12. Feedwater Heater Tube Failure Root Cause Evaluation 4.0 Conclusions 5.0 Recommendations 6.0 References Report on Fact Finding Meeting at DCPP on March 23-24, 2022 1.0 Summary 2.0 Introduction 3.0 Discussion 3.1. Refueling Outage 1 R23 Safety Plan 3.2. Post-Shutdown License Amendment Requests 3.3. Independent Spent Fuel Storage Installation License Renewal Application 3.4. Attend Notification Review Team Meeting 3.5. Emergency Preparedness Program 3.6. Strategic Engineering Department Update xi D.5-6 D.5-7 D.5-9 D.5-13 D.5-14 D.5-15 D.5-18 D.5-19 D.5-20 D.5-22 D.5-22 D.5-24 D.5-24 D.6-1 D.6-1 D.6-2 D.6-2 D.6-2 D.6-2 D.6-4 D.6-4 D.6-5 D.6-6 D.6-7 D.6-9 D.6-11 D.6-11 D.6-13 D.6-15 D.6-16 D.6-17 D.6-17 D.7-1 D.7-1 D.7-1 D.7-2 D.7-2 D.7-5 D.7-7 D.7-10 D.7-11 D.7-12

I 3.7. Inadvertent Boric Acid Addition Event D.7-14 I

3.8. Integrated Risk Management D.7-16 I

3.9. Benchmarking Program D.7-17 3.10. Meet with DCPP Officer D.7-18 3.11. Plant Tour D.7-18 I

3.12. Meet with Nuclear Regulatory Commission (NRC)

D.7-21 Acting Senior Resident Inspector 3.13. Quality Verification D.7-21 I

3.14. Direct Current Power Systems D.7-24 4.0 Conclusions D.7-25 5.0 Recommendations D.7-27 I

6.0 References D.7-27 D.8 Report on Fact Finding Meeting at DCPP on April 12-13, 2022 D.8-1 I

1.0 Summary D.8-1 2.0 Introduction D.8-1 3.0 Discussion D.8-2 I

3.1. Meet with Acting NRC Senior Resident Inspector D.8-2 3.2. FLEX Program Update D.8-2 3.3. Maintenance Rule Program Status D.8-4 I

3.4. NRC Office of Inspector General Report on Counterfeit, D.8-6 Fraudulent and Suspect Parts 3.5. Quality Verification Elevated Audit Findings D.8-8 I

3.6. Radiation Protection During Refueling Outage 1 R23 D.8-8 and Tour of Containment 3.7. Observe Outage 1 R23 Outage Control Center D.8-11 I

3.8. Workplace Seismic Safety D.8-14 3.9. Configuration Management Program D.8-14 3.10. New Independent Spent Fuel Storage Installation Cask D.8-16 I

System 3.11. Human Performance Update D.8-17 3.12. Meet with DCPP Officer Adam Peck, Site Vice President D.8-18 I

3.13. Observe Corrective Action Review Board Meeting D.8-19 4.0 Conclusions D.8-20 5.0 Recommendations D.8-21 I

6.0 References D.8-21 D.9 Report on Fact Finding Meeting at DCPP on May 18-19, 2022 D.9-1 I

1.0 Summary D.9-1 2.0 Introduction D.9-1 I

3.0 Discussion D.9-2 3.1. Learning Services Department D.9-2 3.2. New Spent Fuel Storage System D.9-3 I

3.3. Containment Structure Inspections D.9-5 3.4. Nuclear Fuel Performance D.9-7 3.5. Flow Accelerated Corrosion Program D.9-8 I

3.6. Containment Spray System D.9-10 xii I

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3. 7. Radiation Protection Department Performance During Refueling Outage 1 R23 3.8. Meet with Nuclear Regulatory Commission (NRC) Acting Senior Resident Inspector 3.9. Meet with DCPP Director 3.10. Capital Project Planning 3.11. Refueling Outage 1 R23 Results 3.12. Online Maintenance Scheduling 3.13. Maintenance Department 3.14. Foreign Material Exclusion Program Conclusions Recommendations References Record of DCISC Tours of DCPP DCISC Open Items List DCISC Public Contacts G. l DCISC Email Correspondence Log G.2 DCISC Correspondence G.3 Public Comments Received at Public Meetings Second Restatement of the Charter for the Diablo Canyon Independent Safety Committee H.1 Second Restated Charter, Effective as of November 10, 2021 H.2 Post-Shutdown Phases and Timeline, DCISC Post-Shutdown Matrix, Sample Post-Shutdown Future Open Items List Following Cessation of Electrical Generation Activities Current & Past DCISC Recommendations and PG&E Responses DCISC Informational Brochure Glossary of Terms xiii D.9-11 D.9-12 D.9-12 D.9-13 D.9-15 D.9-17 D.9-18 D.9-20 D.9-21 D.9-22 D.9-22 E-1 F-1 G.1-1 G.1-1 G.2-1 G.3-1 H-1-1 H.1-1 H.2-2 I-1 J-1 k-1

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1.0 INTRODUCTION

1.1 Formation of the Independent Safety Committee The concept of an independent safety committee for Diablo Canyon Nuclear Power Plant CDiablo Canyon") arose in context of the opposition by the California Public Utilities Commission *s (CPUC) Division of Ratepayer Advocates (now known as the Office of Ratepayer Advocates) and the then California Attorney General (John Van de Kamp) to Pacific Gas &

Electric's (PG&E) request for recovery from its ratepayers for the cost of building Diablo Canyon and its two 4-loop Westinghouse pressurized water reactors fueled by uranium dioxide, each of which produces 1,100 megawatts. Those parties argued that billions of dollars of these costs were unreasonable. A settlement agreement arose out of rate proceedings that had been pending before the CPUC for four years and which included numerous hearings and pre-trial depositions. To resolve the matter, on June 24, 1988, just prior to the commencement of trial, the Division of Ratepayer Advocates, the Attorney General and PG&E prepared and entered into the Settlement Agreement in the proceeding which provided for **performance based pricing'" and submitted it to the CPUC for approval. Opponents of the Settlement Agreement, including The Utility Reform Network (TURN), argued that performance based pricing gave PG&E an incentive to maximize energy production and profits which could threaten plant safety.

The Settlement Agreement was intended to cover the operation and revenue requirements associated with Diablo Canyon's two units for a 30-year period following the commercial operation date of each unit. The operating license for Unit 1 was issued on November 2, 1984, and Unit 1 commenced commercial operation on May 7, 1985 and is licensed to operate until November 2, 2024. The operating license for Unit 2 was issued on August 26, 1985, and Unit 2 commenced commercial operation on March 3, 1986, and is licensed to operate until August 26, 2025.

The CPUC recognized the safety implications of establishing performance based pricing for power produced by Diablo Canyon. The Settlement Agreement and its supplemental Implementing Agreement were referred to the CPUC for review and approval. Following hearings before a CPUC Administrative Law Judge and the Commission itself, the CPUC, in December 1988 in Decision D. 88-12-083, approved the Settlement Agreement and established the Diab lo Canyon Independent Safety Committee (DCISC), finding that it was reasonable and "in the public interest" and that the "Safety Committee will be a useful monitor of safe operation at Diablo Canyon." The initial Charter for the DCISC was included in D. 88-12-083 as Attachment A to Appendix C.

The Settlement Agreement provided that:

"An Independent Safety Committee shall be established consisting of three members, one each appointed by the Governor of the State of California, the Attorney General and the Chairperson of the California Energy Commission

("CEC"), respectively, serving staggered three-year terms. The Committee shall review Diablo Canyon operations for the purpose of assessing the safety of 1-1

operations and suggesting any recommendations for safe operations. Neither the Committee nor its members shall have any responsibility or authority for plant operations, and they shall have no authority to direct PG&E personnel. The Committee shall conform in all respects to applicable federal laws, regulations and Nuclear Regulatory Commission ("NRC") policies."

The Settlement Agreement further provided that the DCISC shall have the right to receive certain operating reports and records of Diablo Canyon, and that the Committee shall have the right to conduct an annual examination of the Diab lo Canyon site and such other supplementary visits to the plant site as it may deem appropriate. The DCISC is to prepare an annual report and such interim reports as may be appropriate, which shall include any recommendations of the Committee.

As required by the provisions of certain CPUC decisions and of Assembly Bill 1890 enacted by the California Legislature in 1996, which mandated electric utility rate restructuring and deregulation, PG&E filed an application which proposed replacing the performance based pricing approved in D. 88-12-083 with a rate-making treatment for Diablo Canyon which would have priced the plant's output at market rates by the end of 200 l. On May 21, 1997, the CPUC issued Decision 97-05-088 which, while making the Diablo Canyon settlement adopted in Decision 88-12-083 of no further force and effect, found that the DCISC remained a key element of monitoring the safe operation of Diablo Canyon and continued the DCISC. Decision 97-05-088 ordered that the DCISC remain in existence under the terms and conditions of the Settlement Agreement until further order of the CPUC.

On May 27, 2004, the CPUC issued Decision 04-05-055, the Test Year 2003 General Rate Case, setting the PG&E's revenue requirements for its electric generation operations. In Decision 04 055 the CPUC also: l) adopted a Stipulation between the DCISC, PG&E, the Office of Ratepayer Advocates, The Utility Reform Network, the California Energy Commission (CEC) and the San Luis Obispo Mothers for Peace which provided for the DCISC's continued existence and funding through PG&E's cost-of-service rates, at the funding levels established by Decision 97-05-088 and based the Committee's funding on calendar year 1996 with a 1.5% annual escalation each year thereafter; 2) changed the nomination procedures for DCISC membership to eliminate from the process the participation of PG&E and the Dean of Engineering at the University of California at Berkeley; 3) modified somewhat the qualification requirements for DCISC membership; and 4) added a new requirement for public outreach in the San Luis Obispo area communities to the Committee*s mandate.

On January 25, 2007, the CPUC issued Decision 07-01-028. The CPUC had previously adopted new practices and expectations for the DCISC without concurrently restating the Committee's Charter to reflect those changes. In Decision 07-01-028, the CPUC granted the DCISC application for authority to restate its charter including the incorporation into the Restated Charter of several terms, conditions, changes, and clarifications necessitated by, and previously authorized by, the CPUC which governed the composition, responsibilities and operations of the Committee. In its Decision, the CPUC found a Restated Charter to be in the public"s interest as it reflects the latest authority and obligations of the DCISC. The Committee*s application was unopposed.

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I On June 21, 2016, PG&E announced a Joint Proposal with Friends of the Earth, the Natural Resources Defense Council, Environment California, the International Brotherhood of Electrical Works Local 1245, Coalition of California Utility Employees, and the Alliance for Nuclear Responsibility to retire Diablo Canyon at the' expiration of the current operating licenses and to abandon the then ongoing license renewal activities for both units.

On January 11, 2018, the CPUC voted unanimously to adopt Decision D. 18-01-022 approving PG&E's Application to Retire Diablo Canyon by 2025 (see Section 1.6. below).

At the DCISC public meeting on October 23, 2019, the DCISC Members considered and recommended a proposed Second Restatement of the Committee* s Charter ('*Second Restatement'") which would provide for a post-shutdown role for the DCISC to review nuclear fuel-related issues after expiration of Diablo Canyon's operating licenses from the NRC until all fuel was transferred from the spent fuel pool to, and stored within, the Independent Spent Fuel Storage Installation (ISFSI).

On September 9, 2021 the CPUC approved Decision 21-09-003 adopting the Settlement Agreement proposed in the 2018 Nuclear Decommissioning Cost Triennial Proceeding to provide for a post-shutdown role for the DCISC. The Decision stated '"If the Settlement Agreement is approved, the DCISC charter would be revised to allow it to continue in its safety oversight role until all the Diablo Canyon spent nuclear fuel has been moved from wet storage to dry storage..

. " Decision Finding of Fact 66 provides **Based on the Settlement Agreement, the Settling Parties agree to amend the Charter of the DCISC to extend its oversight role on nuclear safety matters until all spent fuel has been transferred from the spent fuel pools to the ISFSI." Decision Ordering Paragraph 3 states **Pacific Gas and Electric Company shall submit any Advice Letters(s) within 30 days of the effective date of this decision to implement the specific terms of the Settlement Agreement approved in this decision."

On October 11, 2021, PG&E submitted Advice Letter 6361-E, a Tier-2 Advice Letter for approval by the Commission's Energy Division of the Second Restatement of the Charter for the DCISC.

Advice Letter 6361-E was approved and made effective as of November 10. 2021. A copy of the approved Second Restatement is included in Volume II as Exhibit H. l The public meeting of the Diab lo Canyon Independent Safety Committee held in Avila Beach, California, on October 19-20, 2021, included the Committee Members adoption of a resolution recognizing that meeting as the l 00th public meeting of the Committee.

The first "Interim Report on Safety of Diablo Canyon Operations," covering the period of January 1 through June 30, 1990, was adopted by the DCISC on June 6, 1991, and there have been thirty-one annual reports since then. This thirty-second annual report covers the period July 1, 2021 - June 30, 2022, and this report was adopted by the DCISC on September 28, 2022, at a public meeting conducted in Avila Beach, California.

1.2 Appointment of Committee Members 1-3

A request for applications is publicly noticed by the CPUC. After receipt of the applications, and an opportunity for public comment on qualified applicants, a list of candidates is selected by the CPUC and provided to the appointing agencies. In accordance with the Second Restated Charter:

• • The President of the CPUC shall review each application to assess the applicanfs qualifications, experience and background, including any conflict of interest and comment received from the public, and shall propose as candidates only persons with knowledge, background and experience in the field of nuclear power facilities and nuclear safety issues who demonstrate they have no conflict of interest... "

In July 1989, when then CPUC President G. Mitchell Wilk announced the initial list of nine candidates nominated for appointment to the DCISC, he noted that:

"... an independent safety committee clearly requires members who could demonstrate objectivity and independence. For this reason, none of the nominees has testified for PG&E or any other party before the CPUC or the Nuclear Regulatory Commission in any proceeding regarding Diablo Canyon:*

The Second Restated Charter provides:

• • No person shall serve as a member of the Committee if he or she has a prior history of supporting or opposing PG&E as a witness or intervenor in nuclear licensing or CPUC proceedings associated with Diablo Canyon."

l.2. l Robert J. Budnitz On October 10, 2007, Robert J. Budnitz, Ph.D. was appointed by California Attorney General Edmund G. Brown Jr. to a term on the Committee expiring June 30, 20 l 0. On April 15, 20 l 0, Attorney General Brown announced the reappointment of Dr. Budnitz to a second three-year term on the Committee commencing July 1, 2010 through June 30, 2013. On June 27, 2013, the CPUC ratified its Presidenf s selection of Dr. Budnitz as one of two candidates for appointment by Attorney General Kamala Harris to serve a three-year term on the DCISC for the period July 1, 2013 to June 30, 2016. During that period, in accordance with California Government Code§ 1302, Dr. Budnitz continued to serve as a member of the Committee pending his reappointment or replacement. On July 7, 2016, Attorney General Harris announced the reappointment of Dr.

Budnitz to serve a three-year term on the Committee commencing July 1, 2016 through June 30, 2019.

On August 14, 2019, California Attorney General Xavier Becerra announced his reappointment of Dr. Robert J. Budnitz to a three-year term on the DCISC beginning on July 1, 2019 and ending on June 30, 2022. On June 2, 2022, by Resolution E-5213, the CPUC ratified President Reynolds' selection of Dr. Budnitz as one of three candidates for consideration by California Attorney General Rob Bonta for appointment to the Committee for a three-year term commencing on July 1, 2022 through June 30, 2025.

Dr. Robert J. Budnitz has been involved with nuclear-reactor safety and radioactive-waste safety for many years. In February 2017 he was elected to the National Academy of Engineering. In 1-4 I

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I March 2017 he retired from the scientific staff at the University of California's Lawrence Berkeley National Laboratory, where he worked on nuclear power safety and security and radioactive-waste management. Since his formal retirement, he has continued to work on these same subjects through a one-person private consulting service. From 2002 to 2007 he was at the University of California's Lawrence Livermore National Laboratory (LLNL), during which period he worked on a two-year special assignment (late 2002 to late 2004) in Washington to assist the Director of the Department of Energy's (DOE's) Office of Civilian Radioactive Waste Management to develop a new Science

& Technology Program. Prior to joining LLNL in 2002, he ran a one-person consulting practice in Berkeley CA for over two decades. In 1978-1980, he was a senior officer on the staff of the U.S.

Nuclear Regulatory Commission, serving as Deputy Director and then Director of the NRC Office of Nuclear Regulatory Research. In this two-year period, Dr. Budnitz was responsible for formulating and guiding the large NRC research program that constituted over $200 million/year at that time. His responsibilities included assuring that all major areas of reactor-safety research, waste-management research, and fuel-cycle-safety research necessary to serve the mission of NRC were adequately supported. From 1967-1978, he was on the staff of the Lawrence Berkeley National Laboratory (LBNL), serving in 1975-1978 as Associate Director of LBNL and Head of LBNL's Energy & Environment Division. During this period, the programs under his direction were in a large mix of diverse areas relevant to DOE, including energy-efficiency, deep-geologic radioactive waste disposal, solar energy, geothermal energy, fusion energy, transportation technology, chemical-engineering for alternate fuels, environmental instrumentation, air-pollution phenomena, and energy policy analysis. He earned a Ph.D. in experimental physics from Harvard in 1968.

Dr. Budnitz served as DCISC Chair during this report period, July I, 2021 through June 30, 2022 l.2.2 Peter Lam On June 3, 2009, Peter Lam, Ph.D., was appointed by Chair Karen Douglas, Esq. of the California Energy Commission (CEC) to a three-year term on the Committee commencing July 1, 2009 through June 30, 2012. On July 12, 2012, CEC Chair Dr. Robert B. Weisenmiller announced his reappointment of Dr. Lam to a second three-year term on the Committee commencing July I, 2012 through June 30, 2015. Dr. Lam was reappointed by Dr. Weisenmiller to third three-year term on the Committee commencing July I, 2015 and ending on June 30, 2018, and subsequently on June 6, 2018, Dr. Weisenmiller announced Dr. Lam's appointment to a fourth three-year term on the Committee beginning on July 1, 2018 and ending on June 30, 2021. On June 25, 2021, CEC Chair David Hochschild announced his reappointment of Dr. Lam to a fifth three-year term on the Committee beginning on July 1, 2021 and ending on June 30, 2024.

Dr. Peter Lam, Administrative Judge Emeritus of the U.S. Nuclear Regulatory Commission, is an international authority of nuclear reactor operating experience, and a leading expert on nuclear reactor safety and risk assessment. Dr. Lam is now the principal of EMM International, a consulting company with a group of experts in the nuclear industry. In his 18 years of public service as an Administrative Judge, Dr. Lam has presided over numerous public proceedings to decide technical issues of national and international significance involving the use of nuclear energy and materials. Judge Lam* s jurisdiction covered all 104 nuclear power plants, some 21,000 medical and material licensees, and nuclear waste storage in the United States. The ultimate 1-5

resolution of these significant technical issues has contributed to the enhancement of nuclear reactor safety.

Prior to his judicial appointment in 1990, Dr. Lam had extensive technical and managerial experience in the nuclear energy business over a period of 20 years. He was a nuclear engineer at General Electric Company, participating in the design and analysis of boiling water reactor advanced fuels. Dr. Lam served as a program manager at Argonne National Laboratory, managing the research and development of advanced fast reactor metal fuels. He was a manager at Science Applications, Inc., and a consultant at NUS Corporation, both major consulting firms in the nuclear industry. Dr. Lam's responsibilities there involved the management of probabilistic risk assessments of operating nuclear reactors. He managed a group of technical specialists in the U.S.

Nuclear Regulatory Commission in the analysis and evaluation of nuclear reactor operating experience. Dr. Lam was also a visiting faculty member at California State University at San Jose, and at George Washington University.

Dr. Lam has published 71 technical papers and reports in national and international journals and in proprietary company publications which focus on major issues in nuclear transport theory, nuclear reactor fuel design, nuclear reactor operating experience, and nuclear reactor safety. Judge

• Lam has also issued over 110 published judicial decisions related to some 50 cases of litigation.

These judicial decisions resolve a wide range of technical and legal issues regarding nuclear reactor safety, nuclear waste disposal, and other civilian use of nuclear technology.

Dr. Lam has presented lectures at International Atomic Energy Agency (IAEA) international conferences in Austria, Korea, and Spain on significant results in comprehensive analyses of nuclear reactor operating experience. He has chaired an IAEA working group to develop a technical treatise for the analysis and evaluation of operating experience of the world's nuclear reactors. These activities contribute to the international exchange of important information to improve nuclear r_eactor safety.

Dr. Lam earned a Ph.D. and a M.S., both in nuclear engineering, from Stanford University in 1971 and 1968, respectively. He earned a B.S., in mechanical engineering, from Oregon State University in 1967. His four-year undergraduate study at Oregon State University and his four-year graduate study at Stanford University were fully funded by eight consecutive scholarships and fellowships.

1.2.3 Per F. Peterson On July 9, 2008, California Governor Arnold Schwarzenegger announced the appointment of Per F. Peterson, Ph.D., PE, to a three-year term on the Committee through June 30, 2011. Prof.

Peterson previously served as a Committee member from September 2, 2004, through October 9, 2007. Governor Edmund G. Brown Jr. reappointed Professor Peterson to a term on the Committee commencing July 1, 2011 through June 30, 2014. Professor Peterson was subsequently reappointed by Governor Brown to a three-year term on the DCISC commencing July 1, 2014 and expiring on June 30, 2017. On October 11, 2017, Governor Brown reappointed Professor Peterson to a three-year term on the Committee commencing July 1, 2017 and expiring June 30, 2020. In February 2021 Governor Newsom reappointed Dr. Peterson to a sixth three-year term commencing July 1, 2020 through June 30, 2023.

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Per F. Peterson is the Floyd Professor of Nuclear Engineering at the University of California, Berkeley. In February 2020 he was elected to the National Academy of Engineering. Dr.

Peterson was recently awarded the 2022 American Nuclear Society's Walter H. Zinn Medal. The Zinn medal is one of the most prestigious awards in the nuclear-engineering field to recognize an individual for outstanding contributions to the advancement or implementation of nuclear technology.

Since July 2017 Dr. Peterson has also served as the Chief Nuclear Officer for Kairos Power, a start-up company developing advanced reactor technology. He previously chaired the Nuclear Engineering department from 2000 to 2005 and from 2009 to 2012 and chaired the Energy and Resources Group at U.C. Berkeley from 1998 to 2000. He received his Bachelor of Science Degree in Mechanical Engineering at the University of Nevada, Reno, in 1982. After working at Bechtel on high-level radioactive waste processing from 1982 to 1985, he received a Master of Science degree in Mechanical Engineering at the University of California, Berkeley in 1986 and a Ph.D.

in 1988. He was a Japan Society for the Promotion of Science (JSPS) Fellow at the Tokyo Institute of Technology from 1989 to 1990 and a National Science Foundation Presidential Young Investigator from 1990 to 1995. He is past chairman of the Thermal Hydraulics Division ( 1996-1997) and a Fellow (2002) of the American Nuclear Society, a recipient of the Fusion Power Associates Excellence in Fusion Engineering Award (1999) and has served as editor for three technical journals.

Prof. Peterson's research in the 1990's contributed to the development of the passive safety systems used in the General Electric Company's Economic Simplified Boiling Water Reactor (GE ESBWR) and Westinghouse AP-1000 reactor designs. Currently his research group focuses primarily on heat transfer, fluid mechanics, and regulation and licensing for high temperature reactors, principally designs that use liquid fluoride salts as coolants. He is author of over 110 archival journal articles and over 120 conference publications on these topics.

On January 29, 2010, U.S. Department of Energy Secretary Dr. Steven Chu appointed Prof.

Peterson as a member of the Blue Ribbon Commission on America's Nuclear Future ('*BRC""),

established by President Obama to provide recommendations for solutions to manage the Nation's spent fuel and high-level waste. He co-chaired the BRC's Reactor and Fuel Cycle Technology Subcommittee with Senator Pete Domenici. He has served as a member or chair of numerous advisory committees for the national laboratories and National Research Council. He participated in the development of the Generation IV Roadmap in 2002 as a member of the Evaluation Methodology Group, and has co-chaired its Proliferation Resistance and Physical Protection Working Group since 2002.

Dr. Peterson served as DCISC Vice-Chair during this report period, July 1, 2021 through June 30, 2022 1.2.4 Technical Consultants & Legal Counsel The Restated Charter provides the Committee may contract for services including the services of consultants and experts to assist the Committee in its safety review. The DCISC 1-7

Members are assisted in their important work by technical consultants and legal counsel. For this report period those persons were:

Technical Consultant: Mr. R. Ferman Wardell, a Registered Professional Engineer, holds both Bachelor and Master of Science degrees in Nuclear Engineering from North Carolina State University. He is a 53-year veteran of the nuclear power industry, having been directly involved in design, quality assurance, operation and nuclear safety oversight activities for Duke Energy Corporation *s seven nuclear units. He was formerly Executive Assistant to the Chairman and CEO at Duke Energy. Mr. Wardell has been a Consultant to the DCISC since 1992. In this capacity he participates in technical and programmatic reviews of the safety of Diablo Canyon nuclear operations, DCISC public meetings, and development of the DCISC fact-finding reports and its annual reports. Mr. Wardell also serves as nuclear consultant to the minority owner of the North Anna Power Station, a nuclear plant in Virginia.

Technical Consultant: Mr. Richard D. McWhorter, Jr., holds a Bachelor of Science Degree in Mechanical Engineering from the United States Naval Academy. He is a 35-year veteran of the nuclear power industry. He served for ten years as a division officer and department head in the navy*s nuclear submarine program in which he was responsible for the operation of his submarine*s nuclear power plant. Mr. McWhorter then served the U. S. Nuclear Regulatory Commission for ten years, first as an Operator Licensing Examiner and then as Senior Resident Inspector at North Anna Power Station. He then was employed for two years as a Systems Engineering Manager for Dominion Virginia Power at North Anna Power Station. For ten years, Mr. McWhorter was employed at Old Dominion Electric Cooperative where he served as Vice President of Operations and Asset Management. Mr. McWhorter has been a Consultant to the DCISC since 2016. In this capacity he participates in technical and programmatic reviews of the safety of Diablo Canyon nuclear operations, DCISC public meetings, and development of the DCISC fact-finding reports and annual reports.

Legal Counsel: Robert R. Wellington, Esq. has been Legal Counsel for the DCISC since its organization in 1989. He is a graduate of Stanford University and the University of California (Hastings) Law School. For over 30 years his practice has been limited to representing several cities, community service, regional wastewater and solid waste districts and other public agencies, including the DCISC. He advises the DCISC with regard to its legal, regulatory and administrative matters.

Assistant Legal Counsel Robert Rathie, Esq. has been associated with the Committee through his work with the Wellington Law Offices since 1993. He obtained a Bachelor of Arts Degree in Social,Science and History from Chico State University in 1972 and served for 15 years in the U.S. Merchant Marine as chief purser on board passenger and freight vessels in foreign trade. He received his Juris Doctor Degree from Monterey College of Law in 1993. He is a member of the State Bar of California and the Monterey County Bar Association. He advises the DCISC with regard to its legal, regulatory and administrative matters.

1.3 DCISC Public Meetings The DCISC held three public meetings on the following dates:

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I October 19-20, 2021 February 15-16, 2022 June 22-23, 2022 Public Meeting Public Meeting Public Meeting All public meetings during this report period were held in person in Avila Beach, California, in a hybrid format, that is, both in-person and with a virtual component to allow remote participation and were livestreamed on the internet.

These are described in Section 2.0.

1.4 Committee Member Site Inspection Tours and Fact-finding Meetings DCISC Members and Consultant met regularly with Diablo Canyon staff members and the NRC resident inspectors to conduct fact-finding and review operational activities which the Committee has under review or has interest. A record of these fact-finding meetings is contained in Volume II, Exhibits D. l - D.9, and plant tours and inspections are listed in Exhibit E.

1.4.1 Fact-finding Meetings by Robert J. Budnitz To Diablo Canyon on September 13-15, 2021, with Consultant McWhorter to review the Probabilistic Risk Assessment Program; receive an update on staffing, retention and attrition of plant personnel; meet with a Diablo Canyon Officer; receive an update on the response to the COVID-19 pandemic; review the Cause Evaluation for a failed auxiliary saltwater pump; review the Equipment Reliability Process; meet with the NRC Resident Inspector; review the Root Cause Evaluation for the Unit 2 Main Generator failures; receive an update on the Cyber Security Program; receive an update on the Auxiliary Feedwater System; tour the power plant; and observe an Emergency Preparedness Exercise.

A remote meeting January 11-12, 2022, with Consultant Wardell to meet with a Diablo Canyon Officer; review procedures and experience for operator rounds; review Independent Spent Fuel Storage Installation (ISFSI) cask inspections; meet with the NRC Acting Senior Resident Inspector; receive an update on the response to the COVID-19 pandemic; review the health of refueling equipment; receive an update on fire doors and door life management; observe a meeting of the Plant Health Committee; meet with a Diablo Canyon Officer; review single point vulnerabilities; receive information on the Operability Determination Program; and review the root cause evaluation for the feedwater heater tube failure.

To Diablo Canyon on March 23-24, 2022, with Consultant McWhorter to review the refueling outage 1 R23 Safety Plan; review post-shutdown license amendment requests; receive a report on the license renewal application for the ISFSI; attend a meeting of the Notification Review Team; review the Emergency Preparedness Program; receive an update on the Strategic Engineering Department; review the inadvertent boric acid addition event; receive a report on integrated risk management; meet with a Diablo Canyon Officer; tour the power plant; meet with the NRC Acting Senior Resident Inspector; receive an update on the activities of the Quality Verification organization; and review the direct current power systems.

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1.4.2 Inspections and Fact-finding Meetings by Peter Lam To Diablo Canyon on August 18-19, 2021, with Consultant Wardell to remotely observe a meeting of the Plant Health Committee; meet remotely with PG&E"s Chief Nuclear Officer; review remotely Diablo Canyon*s Safety Culture and Safety Conscious Work Environment" meet with the both NRC Resident Inspectors; receive an update on the Institute of Nuclear Power Operations* (INPO) Mid-Cycle Evaluation; tour the Intake Structure and receive an update on the inspection of the concrete at the Intake Structure; review software quality assurance; receive an update on plant chemistry matters; and review the health of the Reactor Coolant System.

To Diablo Canyon on November 16-17, 2021, with Consultant Wardell to observe licensed operator training for loss of heat sink; receive results of the ISFSI cask inspection; receive an update on digital systems; meet with the NRC Senior and Resident Inspectors; review the feedwater heater tube failure and forced reactor shutdown; receive an update on the Operating Experience Program; observe remotely a meeting of the Plant Health Committee; observe training conducted in the Simulator Facility on Anticipated Transient Without Scram events; review the results of the NRC Ultimate

. Heatsink Inspection; and meeting with a Diab lo Canyon Officer.

To Diablo Canyon on May 18-19, 2022, with Consultant McWhorter to review the Learning Services Department; receive information on the new spent fuel storage system; review the results of the Containment Structure Inspections; receive an update on nuclear fuel performance; review the Flow Accelerated Corrosion Program; review the Containment Spray System; review the' performance of the Radiation Protection Department during refueling outage 1 R23; meet with the NRC Acting Senior Resident Inspector; meet with a Diablo Canyon Director; review capital project planning; review the results of refueling outage 1 R23; receive information on scheduling online maintenance; and review the Foreign Material Exclusion Program.

1.4.3 Inspections and Fact-finding Meetings by Per F. Peterson On July 14-15, 2021, with Consultant McWhorter to observe an Operations turnover and focus meeting; to receive an update on emergency preparedness; to meet with the NRC Resident Inspector; review the Annual Radioactive Effluent Release Report and the Annual Radioactive Environmental Operating Report; receive an update on lessons learned from the Texas extreme weather event; meet with a Diablo Canyon Officer; review the program for managing changes under l O CFR 50.59; review the Management Observation Program; receive an update on the

• health of the emergency diesel generators; tour the power plant; review the refueling outage 2R22 Safety Plan; observe an exit meeting of the Nuclear Safety Oversight Committee; and receive an update on the Radiation Protection Department.

To Diablo Canyon on December 7-8, 2021, with Consultant McWhorter to review the root cause evaluation for a failed auxiliary saltwater pump motor; review the Transmission System; meet with the NRC Senior Acting Resident Inspector; review trends in plant status control events; receive an update on the Crane Program; tour the power plant; observe a training class in* the Simulator Facility; review follow-up items for the Emergency Diesel Generator System; observe a meeting of the Plant Health Committee; receive an update on personnel staffing, retention and attrition; 1-10 I

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I review the Meteorological Information and Dose Assessment System; and meet with a Diablo Canyon Officer.

To Diablo Canyon on April 12-13, 2022, with Consultant Wardell to meet with the NRC Acting Senior Resident Inspector; to receive an update on the FLEX Program; review the status of the Maintenance Rule Program; review the NRC Office of Inspector General's Report on counterfeit, fraudulent and suspect parts; review the findings of the elevated audit of the Quality Verification organization; review radiation protection during refueling outage 1 R23 and tour Containment; observe activities at the Outage Control Center during refueling outage 1 R23; review workplace seismic safety; review the Configuration Management Program; review the new ISFSI cask system; receive an update on human performance; meet with Diablo Canyon Officer; and observe a meeting of the Corrective Action Review Board.

1.4.4 Tours of Diablo Canyon by DCISC Members and Members of the Public The DCISC has conducted tours of Diab lo Canyon Power Plant in past years with members of the public in conjunction with certain of its public meetings. Due to the COVID-19 pandemic access to Diablo Canyon was limited only to personnel essential to its operation and social distancing protocols and precautions related to COVID-19 remained in place during this annual report period to protect Diablo Canyon personnel. Accordingly, no public tours were conducted during this annual report period.

The DCISC will assess its ability to continue to conduct tours of the power plant with members of the public when conditions might permit the activity to resume.

1.5 Visits by DCISC Members to California State Agencies, Outreach Activities to the Diablo Canyon Decommissioning Engagement Panel, and Outreach Activities to the Diablo Canyon Independent Peer Review Panel.

1.5.1 Visits by DCISC Members to California State Agencies, The DCISC's preference is to schedule annual meetings between its Members and their respective appointing entities and with the Commissioners or staff members of the California Public Utilities Commission to provide background on and information regarding current activities of the Committee.

The Second Restated Charter provides for the Committee to undertake outreach concerning matters within its purview with other review committees established by the CPUC including the Independent Peer Review Panel for Seismic Studies at Diablo Canyon and the Diablo Canyon Decommissioning Engagement Panel.

On April 28, 2022, DCISC Member Dr. Peter Lam and Assistant Legal Counsel Robert Rathie met remotely via a Zoom video conference with California Energy Commission ('*CEC")

Chair Mr. David Hochschild, CEC Senior Nuclear Policy Advisor and Emergency Coordinator Dr. Justin Cochran and CEC Chief Policy Advisor Kenneth Rider. The discussion during the meeting included retention, recruiting, and personnel attrition issues at Diablo Canyon including 1-11

recent changes in senior plant leadership; budget and investment matters with reference to equipment replacement and the Nuclear Decommissioning Cost Triennial Proceedings; the recent issuance by the NRC Office of the Inspector General of a report critical of the inspection protocol in connection with a failure of the Auxiliary Feedwater System piping; developments concerning the licensing of the NUHOMS new dry cask storage system for spent nuclear fuel, the lack of inventory of any Holtec manufactured casks on the site, and the initial licensing and schedule and inspections in conjunction with the current relicensing process for the Diablo Canyon Independent Spent Fuel Storage Installation; and cyber security issues.

On May 10, 2022, DCISCChair Dr. Robert J. Budnitz and As'sistant Legal Counsel Robert Rathie met remotely via BlueJeans video conferencing with members of the California Attorney General's staff including Chief Assistant Attorney General for Public Rights Mr. Matt Rodriguez, Senior Assistant Attorney General Mr. Ed Ochoa, Special Assistant Attorney General-Environmental Ms. Yana Garcia, Supervising Attorney General Ms. Laura Zuckerman, and Deputy Attorney General Ms. Megan Hey. The discussion during the meeting included review of the origin of the DCISC, the backgrounds and qualifications of its current members, and the relation between rationale and circumstances that resulted in creation of the DCISC and the present situation during which the Committee is tasked to continue to perform its safety review role as Diablo Canyon plans to cease operations; a review of the decommissioning process, inspection and maintenance issues including quality assurance and the availability of parts, capital projects, and management changes, retention of key employees and experience; the roles of the NRC and the Institute of Nuclear Power Operations and the function and efficacy of the Operating Experience Program; concerns regarding aging, radiological release, and the management of spent nuclear fuel; the design and capacities in terms of assemblies, heat load and seismic anchoring of the new spent fuel storage casks; the NRC Office of the Inspector General's report on the inspection of piping for the Auxiliary Feedwater System which subsequently failed; the role of the Diablo Canyon Decommissioning Engagement Panel with reference to plans for reuse of Diab lo Canyon lands, and other issues of interest to the Attorney General's representatives.

1.5.2 Outreach Activities to the Diablo Canyon Decommissioning Engagement Panel.

The Diablo Canyon Decommissioning Engagement Panel (DCDEP) was convened by PG&E as a volunteer, non-regulatory body created to foster and encourage open communication, public involvement and education on Diablo Canyon decommissioning plans and activities. It is intended to serve as a forum for the local community to provide direct input to PG&E and regulatory agencies on matters related to Diablo Canyon decommissioning. The DCDEP functions solely in an informational and advisory capacity. The meetings and workshops held by the DCDEP allow local community members to provide direct input to PG&E, and subject matter experts to provide information to the panel and the public about Diablo Canyon decommissioning.

The DCDEP was formed in 2018 to help inform PG&E's site-specific decommissioning plans including future land use and repurposing recommendations. Final decisions regarding Diablo Canyon decommissioning will be made by PG&E in conjunction with the appropriate regulatory agencies. PG&E has expressed its intention to continue to engage with the DCDEP and solicit input from the public during the multi-year decommissioning process.

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I The DCDEP is comprised of representatives from the local community. Each member of the DCDEP serves a three-year term (following the initial staggering of terms). The inaugural panel was formed in May 2018 and served staggered terms as assigned by the membership at its first meeting through a facilitated process. Membership is renewed or vacancies filled through approval by a majority of the community members of the DCDEP and PG&E consistent with the DCDEP Charter. In June 2020, PG&E reponed an application period for membership on the DCDEP. New members were selected to fill expiring terms and a vacancy due to resignation.

The DCDEP presently consists of 11 public members,, a PG&E Vice President as PG&E"s representative, and the Director of Planning for the County of San Luis Obispo and a representatives of yak titYu yak tilhini, Northern Chumash Tribe who serve as ex-officio members of the DCDEP.

During the period of the 32nd Annual Report the DCDEP held public meetings on August 25, 2021 to discuss proposals for the reuse of Diablo Canyon facilities and the proposed Decision in the 2018 NDCTP; November 3, 2021, to review and discuss the land use and the California Environmental Quality Act process; April 20, 2022, to receive information on an award for a new spent fuel storage system during which DCISC Chair Dr. Budnitz gave a presentation; and May 25, 2022, to continue the discussion concerning the new spent fuel storage system, which was attended remotely by Dr. Budnitz and the Committee's Technical Consultants. Ms. Linda Seeley, a Member of the DCDEP who serves as the DCDEP's unofficial liaison to the DCISC, gave a presentation to the DCISC concerning the recent activities of the DCDEP at the DCISC public meeting on February 16, 2022, which is described in the Minutes of that meeting, Exhibit B.6.

1.5.3 Outreach Activities to the Diablo Canyon Independent Peer Review Panel (IPRP).

In 2006, the California legislature enacted Assembly Bill (AB) 1632 which directed the California Energy Commission (CEC) to assess the potential vulnerability of the state's nuclear plants to major disruptions, including seismic events. The CEC's resulting AB 1632 report recommended that the utilities perform enhanced seismic studies with two-and three-dimensional seismic surveys in the areas onshore and offshore from Diablo Canyon and the San Onofre Nuclear Generating Station in Southern California. In Decision 10-08-003, the CPUC approved funding for Diablo Canyon seismic studies and established the Independent Peer Review Panel (IPRP) to review them The IPRP is tasked with providing expertise to the CPUC while also assuring the public that the studies are being performed in an appropriate manner. Passage of AB 361 in October 2015 extended funding for the IPRP through 2025, the last year of the powerplant's current operating licenses.

The IPRP is comprised of technical experts from the CEC, California Geological Survey, California Coastal Commission, California Seismic Safety Commission, and the County of San Luis Obispo. PG&E submits its seismic studies to the IPRP for review, the most recent of which was its Central Coastal California Seismic Imaging Project (CCCSIP) report, submitted in September 2014. Following the submission of these studies, the IPRP convenes for public meetings to review and discuss the results, and ultimately submits an IPRP Report. Since the IPRP's inception it has issued ten reports.

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During the period of the 32nd Annual Report the IPRP held a virtual public meeting on November 3, 2021. DCISC Chair Dr. Budnitz attended and participated in this meeting.

1.6 Retirement of Diablo Canyon Power Plant at Expiration of its Current Operating Licenses, Establishment of a Post-Shutdown Role for the DCISC, and PG&E's Civil Nuclear Credit Program Application.

1.6.1 Background of CPUC Decision 18-01-022 Approving the Retirement of Diab lo Canyon QY 2025 and CPUC Decision 21-09-003 in the 2018 Nuclear Decommissioning Cost Triennial Proceeding providing for a post-shutdown role for the DCISC..

On June 21, 2016, PG&E announced a Joint Proposal with Friends of the Earth, the Natural.

Resources Defense Council, Environment California, the International Brotherhood of Electrical Works Local 1245, Coalition of California Utility Employees and the Alliance for Nuclear Responsibility to retire Diablo Canyon at the expiration of the current operating licenses from the NRC and to abandon license renewal activities for both units.

The Joint Proposal provided for PG&E's continued operation of Diablo Canyon at present generation levels through the current NRC license periods with retirement of Unit-I in 2024 and retirement of Unit-2 in 2025. The Joint Proposal provided for replacement of Diablo Canyon's power by the procurement of 2,000 gigawatt hours of energy efficient power by the end of 2024 and for recovery by PG&E of its investment in Diablo Canyon including for prior activities in furtherance of relicensing the plant.

To replace Diablo Canyon power the Joint Proposal provided for specific greenhouse gas-free procurement requirements which would commence in 2018 and continue through 2031. The Joint Proposal also provided for PG&E to implement employee retention and severance programs to retain existing employees through a retention incentive payment program of a 25% bonus based an employee's annual salary in accordance with two tranches followed by the severance program, and to provide resources and assistance to transitioning workers. The Joint Proposal also proposed that PG&E would continue to provide funding to the San Luis Obispo local community after 2025 to replace lost tax revenue.

On August 11, 20 I 6, PG&E filed Application 16-08-006 ("'Application"') with the California Public Utilities Commission (CPUC) for approval of the retirement of Diablo Canyon, implementation of the Joint Proposal, and for recovery of associated costs through proposed ratemaking.

In summary, in its Application PG&E sought authorization from the CPUC to:

• Retire Diablo Canyon by the end of its current operating licenses from the NRC, that is, by November 2, 2024 for Unit-I and by August 26, 2025 for Unit-2.

• Recover the full book value of both units by the time they cease operations.

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• Conduct procurement activities in three separate tranches related to the replacement of power generated.by Diablo Canyon with greenhouse gas (GHG)-free energy resources beginning in 2018 and continuing through 2031 (tranches two and three were subsequently withdrawn from the Application and a request made that the matter ofreplacement power be addressed in the CPU C's Integrated Resource Planning Proceedings).

• Recover $352.1 million in costs for an Employee Retention Program, to implement an employee severance program, and $11.3 million to retrain eligible Diablo Canyon employees.

• Continue to provide support to state and local authorities for emergency preparedness activities during decommissioning.

• Provide $85 million for a Community Impacts Mitigation Program to help offset property tax loss for San Luis Obispo County local entities.

• Recover $52. 7 million in costs associated with license renewal activities; and an unspecified amount for cancelled capital projects.

On November 8, 2017, CPUC Administrative Law Judge Peter Allen issued Proposed Decision D. 18-01-022 approving the Retirement of Diab lo Canyon. The Proposed Decision denied PG&E' s request to recover in its rates the Community Impact Mitigation funding proposed for the San Luis Obispo area and recommended consideration of electricity procurement to replace Diablo Canyon power should be addressed in the CPUC's Integrated Resources Planning procurement proceedings. The Proposed Decision did not include full funding for the Employee Retention Program instead reducing the ratepayer-supported employee retention incentive payments from 25% to 15% per year.

On January 11, 2018, the CPUC voted unanimously to adopt Decision D. 18-01-022 approving PG&E's Application to retire Diablo Canyon by 2025, approving PG&E's recovery in its rates the costs associated with the retirement of the power plant; costs incurred for license renewal expenses; to retain Diablo Canyon employees until scheduled closing, and to retrain workers. The Decision, which was issued on January 16, 2018, in approving $211.3 million and not the $352.1 million sought by PG&E did not approve full funding by the ratepayers for the Employee Retention Program as proposed in PG&E's its Application and instead directed, consistent with the Proposed Decision, that the ratepayer-supported employee retention incentive payments be reduced from 25% to 15% per year. The CPUC denied in its entirety PG&E's request to recover in its rates the Community Impact Mitigation funding provided to the San Luis Obispo area and determined that consideration of electricity procurement to replace Diablo Canyon power should be addressed in the CPUC's Integrated Resources Planning procurement proceedings. In October 2018, the Commission denied an Application for Rehearing of Decision 18-01-022 filed by the group Californians for Green Nuclear Power.

On February 12, 2018, State Senator William Monning introduced California Senate Bill ('"SB")

1090 to require and direct the CPUC to approve the full funding requested by PG&E in its Application for the Community Impact Mitigation and the Employee Retention Programs and 1-15

require the CPUC to ensure that the Integrated Resources Planning procurement proceedings avoid any increase in emissions of greenhouse gases as the result of the retirement of Diablo Canyon.

On March 7, 2018, PG&E formally requested the NRC to withdraw its license renewal application for both Diablo Canyon units.

On May 1, 2018 PG&E announced its formation of the Diab lo Canyon Decommissioning Engagement Panel (DCDEP) consisting of eleven members of the local community to provide community input to PG&E on topics including, but not necessarily limited to, the site-specific decommissioning plan, potential future uses of the site, facilities and lands, the economic impacts resulting from the closure of the power plant, emergency planning, used fuel storage, and the 2018 Nuclear Decommissioning Cost Triennial Proceeding. Since the creation of the DCDEP the DCISC has had regular informal interactions with the DCDEP and its members and continues to work with the DCDEP's assigned liaison to the DCISC, previously Dr. Lauren Brown and now Ms. Linda Seeley, to maintain an effective working relationship. In accordance with the Second Restatement of the Charter for the DCISC the Committee shall undertake outreach concerning matters within its purview with the DCDEP.

On May 22, 2018, the DCISC sent a letter in support of those aspects of SB 1090 with regard to appropriate funding for the Employee Retention Program to Senator Monning and expressed its opinion that a well-designed and appropriately funded employee retention incentive program was essential to Diablo Canyon's safe operation until retirement and, while the DCISC did not opine on what precise funding level was appropriate, the 15% proposal seemed to the Committee to be inadequate based on the Committee Members' interactions with the plant staff.

On July 16, 2018, PG&E filed with the CPUC Application A-18-07-013 for Authorization to Establish the Diablo Canyon Decommissioning Planning Memorandum Account to track the cost of decommissioning planning activities.

In September 2018, Governor Brown signed SB 1090 into law.

On December 7, 2018, the CPUC issued Decision 18-11-024, modifying in part Decision 18 022 in compliance with California Public Utilities Code Section 712. 7 (added by SB l 090) authorizing PG&E: ( 1) to collect an additional $225.8 million in rates over the amounts authorized in Decision 18-01-022, that is: (i) an additional amount of $140.8 million for the Employee Retention Program through the existing ratemaking treatment for Diablo Canyon; and (ii) an additional amount of $85 million for the Community Impacts Mitigation programs through the nuclear decommissioning non-bypassable charge; (2) ensuring the Integrated Resource Planning energy procurement process is designed to avoid any increase in emissions of greenhouse gases as a result of the retirement of Diablo Canyon; (3) establishing an expedited Tier 1 advice letter process for implementing the rate increases for the Employee Retention and Community Impacts Mitigation programs; and (4) closing the proceeding.

On December 13, 2018, PG&E filed with the CPUC Application A-18-12-008 in the 2018 Nuclear Decommissioning Cost Triennial Proceeding (2018 NDCTP) and submitted prepared testimony.

The purpose of the 2018 NDCTP is to review PG&E' s updated nuclear decommissioning cost 1-16 I

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I estimates and determine the necessary customer contributions to fully fund the nuclear decommissioning trusts to the level needed to decommission PG&E's two nuclear power plants located at Diablo Canyon and at Humboldt Bay California. In the 2018 NDCTP PG&E presented its first detailed, site-specific decommissioning cost estimate and schedule for post shutdown treatment of spent fuel for Diablo Canyon for CPUC review and approval.

In its testimony filed on December 13, 2018, PG&E stated the current dry cask storage design in use at the Diablo Canyon Independent Spent Fuel Storage Installation (ISFSI) is limited by the

'ISFSI Technical Specifications to a minimum cooling of 10 years for the amount of bumup of the Diablo Canyon spent nuclear fuel. The Technical Specifications limits are based on the design basis accident evaluations using the physical properties of the storage system. To accelerate the transition from wet storage to dry storage of spent nuclear fuel before a l 0-year cooling time a dry cask storage design system with a heat load capacity higher than the one currently licensed by the NRC for the Diablo Canyon ISFSI would need to be licensed by the NRC and implemented by Diablo Canyon.

On January 29, 2019 due to extensive litigation and significant liabilities resulting in a deteriorating financial situation as a result of wildfires in California during 2017 and 2018 impacting upon the corporation and the utility, and in accordance with a previously announced plan, PG&E Corporation and Pacific Gas and Electric Company entered Chapter 11 reorganization in bankruptcy. The DCISC continued to monitor and review operations at Diablo Canyon to assess any impact from the bankruptcy on the safety of operations including any impact on decommissioning planning which might or could have an impact on continuing electricity generation operations as a result.

On March 7, 2019, the Assigned Commissioner, CPUC President Michael Picker, issued an Amended Scoping Memo in the 2018 NDCTP consolidating Applications A-18-07-013 and A 12-008. In the Amended Scoping Memo PG&E was directed to respond to additional concerns raised through public comment to the CPUC by San Luis Obispo Mothers for Peace expressing safety concerns as to Unit l and to concerns raised by Mr. Alex S. Karlin concerning the functions, cost, and useful life of the DCISC. PG&E provided Supplemental Testimony responding to both concerns.

On March 15, 2019, after consulting with CPUC Energy Division staff, the DCISC filed a Motion for Party Status in the 2018 NDCTP in order to present testimony as an intervenor to address the issues presented by Mr. Karlin as to the role of the DCISC and to address the possible need for a modification of its Commission-approved Restated Charter should a future post-generation role for the DCISC be determined to be appropriate and should the 2018 NDCTP provide the appropriate forum to pursue such modification. In its Motion, the DCISC stated that it has not to date exceeded its authority under the present Restated Charter nor has it expended significant effort or funds reviewing post-shutdown decommissioning-related matters.

On June 6, 2019, Administrative Law Judge Darcie Houck issued her ruling denying the DCISC's Motion for party status in the 2018 NDCTP. The ruling allows the DCISC to prepare and respond to questions presented to PG&E in the March 7, 2019, Amended Scoping Memo by submitting its responses to the Commission's Energy Division staff and serving those responses on the service list in the proceeding. The ruling provides that the Committee's responses may become part of the 1-17

official record of the 2018 NDCTP proceedings through their attachment to a future ruling issued by the Administrative Law Judge.

On August 7-8, 2019, the CPUC conducted public informational and participation hearings for the 2018 NDCTP in San Luis Obispo, California. At the invitation of the Administrative Law Judge Houck, Assistant Legal Counsel Robert Rathie attended and made a short presentation during the informational hearing describing the Committee"s history, role and the current membership.

On October 11, 2019, the 2018 NDCTP was assigned from Administrative Law Judge Darcie Houck to Administrative Law Judge Robert Haga and on October 17, 2019, the proceedings were assigned to CPUC President Marybel Batjer At its October 2019 and February 2020 public meetings during the prior annual report period, following comments received from members of the public and representatives of certain non-governmental organizations, the DCISC continued its discussion of the issue of a continued role for the Committee to review spent nuclear fuel-related activities and issues after the power plant ceases to generate electricity. At its public meetings on October 23, 2019 and February 12, 2020, the Committee received and considered the proposed amendment of its Restated Charter to provide to a continued role for the DCISC following Diablo Canyon's cessation of electricity generating operations to review nuclear fuel-related issues and to terminate that review upon completion of the safe transfer of all spent fuel to the Diab lo Canyon Independent Spent Fuel Storage Installation (ISFSI).

At the DCISC public meeting on October 23, 2019, the DCISC Members considered a proposed Second Restatement of the Committee's Charter ('*Second Restatement") which would provide for a post-shutdown role for the DCISC to review nuclear fuel-related issues after expiration of Diablo Canyon's operating licenses from the NRC until all fuel was transferred to and stored within the ISFSI. The Committee provided direction to Legal Counsel to prepare a draft Application for CPUC approval of a Second Restatement of its Charter from the CPUC and to circulate a draft for Members' review prior to the February 2020 public meeting but to wait until the 2018 NDCTP has concluded before filing the Application.

On January 10, 2020, a Joint Motion was filed with the CPUC in the 2018 NDCTP for Adoption of a Settlement Agreement between PG&E, The Utility Reform Network, the CPUC Public Advocates Office, the Alliance for Nuclear Responsibility, the County of San Luis Obispo, the yak tityu yak tilhini Northern Chumash Cultural Preservation Kinship, and Women's Energy Matters for approval of the Settlement Agreement which, if approved, would provide for the Committee's Charter to be amended to extend the Committee's oversight role on nuclear safety matters until all spent nuclear fuel has been transferred from the spent fuel pools to the ISFSI.

At the DCISC public meeting on February 12, 2020, following consideration of approval of an Application which was presented to the Committee Members for review at the meeting regarding a Second Restatement of the DCISC's Charter to provide for a continued role following Diablo Canyon's cessation of electricity generating operations for the DCISC to review nuclear fuel-related issues and to terminate that review upon completion of the safe transfer of all nuclear fuel to the ISFSI, the Members approved the proposed Second Restatement presented at that meeting 1-18 I

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as the DCISC"s proposal for a Second Restated Charter for the Committee and directed the Committee*s Legal Counsel to provide the proposed Second Restatement to the CPUC Energy Division staff with a recommendation to pursue the most expeditious avenue to bring the proposed Second Restatement to the attention of the Administrative Law Judge in the 2018 NDCTP for a procedure to be found for consideration of its approval by the CPUC.

On July 1, 2020, PG&E Corporation and Pacific Gas & Electric Company exited Chapter 11 bankruptcy. During and following the bankruptcy period, the DCISC continued to monitor and review operations at Diablo Canyon to assess any impact from the bankruptcy on the safety of operations, including any impact on decommissioning planning which might or could have an impact on continuing electricity generation operations. The bankruptcy filing had no effect on the funding the DCISC receives for its operations and the Committee continued to receive full funding provided by PG&E's ratepayers as required by CPUC Decisions D. 97-05-088 and D. 04-05-055.

The statutory deadline in the 2018 NDCTP (the now combined Applications A-18-07-013 and A-18-12-008) was extended on three separate occasions: first on August 6, 2020 extending the deadline from August 15, 2020 to December 13, 2020; second on December 3, 2020 extending the deadline from December 13, 2020 to March 13, 2021, and finally on March 4, 2020 extending the deadline to September 13, 2021.

1.6.2 32nd Annual Report Period On August 6, 2021, Administrative Law Judge Robert Haga issued a Proposed Decision Adopting Settlement in the 2018 NDCTP.

On September 9, 2021 the CPUC approved Decision 21-09-003 approving the adopting the Settlement Agreement proposed in the 2018 NDCTP to provide for a post-shutdown role for the DCISC. The Decision states **If the Settlement Agreement is approved [by the CPU C's adoption of the Proposed Decision], the DCISC charter would be revised to allow it to continue in its safety oversight role until all the DCPP spent nuclear fuel has been moved from wet storage to dry storage... ** Decision Finding of Fact 66 provides "Based on the Settlement Agreement, the Settling Parties agree to amend the Charter of the DCISC to extend its oversight role on nuclear safety matters until all spent fuel has been transferred from the spent fuel pools to the ISFSI.'"

Decision Ordering Paragraph 3 states *"Pacific Gas and Electric Company shall submit any Advice Letters(s) within 30 days of the effective date of this decision to implement the specific terms of the Settlement Agreement approved in this decision" Hence, the DCISC will continue its nuclear safety oversight role until all spent fuel has been moved from wet to dry storage.

With reference to other matters addressed in the Proposed Decision, the Proposed Decision concluded as follows:

• • This decision approves PG&E* s request to review PG&E* s updated nuclear DC Es

[decommissioning cost estimates] and determine the necessary customer contributions to fully fund the nuclear decommissioning trusts to the level needed to decommission PG&E' s nuclear plants. [Humboldt Bay and Diablo Canyon]. This decision determines an adjusted 2018 Diablo Canyon DCE of $3,899,145,000 ($2017) and a resulting annual revenue requirement of $112.5 1-19

million recovered over eight years (2021-2028) are reasonable. This decision also approves the agreement that reductions attributable to repurposing and other issues related to the post-2022 revenue requirement will be revisited in the 2021 NDCTP and that the reductions agreed to for this cycle will not harm PG&E's ability to fully restore the Diablo Canyon site at the end of decommissioning as required by federal, state or local regulators and found reasonable and prudent in future NDCTPs.

Additionally, in connection with the approval of the reasonableness of Diablo Canyon DCE, trust contribution and related annual revenue requirement for this proceeding, the decision determines it reasonable for PG&E to withdraw $187.8 million from the Nuclear Decommissioning Trust to support pre-shutdown decommissioning planning activities, subject to reasonableness review in the appropriate NDCTP. Further, the costs to renew the license for the Diab lo Canyon Independent Spent Fuel Storage Installation and to perform studies to determine which California Native American Tribe(s) is traditionally and culturally affiliated with Diablo Canyon lands are deemed included in the $187.8 million of decommissioning planning costs."

On September 10, 2021 the CPUC issued Decision 21-09-003, approved by the Commission on September 9, 2021, adopting a Settlement Agreement proposed in the 2018 Nuclear Decommissioning Cost Triennial Proceeding to provide for a post-shutdown role for the DCISC.

The Decision states **If the Settlement Agreement is approved [by the CPU Cs adoption of the Proposed Decision], the DCISC charter would be revised to allow it to continue in its safety oversight role until all the DCPP spent nuclear fuel has been moved from wet storage to dry storage

... " Decision Finding of Fact 66 provides ""Based on the Settlement Agreement, the Settling Parties agree to amend the Charter of the DCISC to extend its oversight role on nuclear safety matters until all spent fuel has been transferred from the spent fuel pools to the ISFSI.'" Decision Ordering Paragraph 3 states ""Pacific Gas and Electric Company shall submit any Advice Letters(s) within 30 days of the effective date of this decision to implement the specific terms of the Settlement Agreement approved in this decision" On October 11, 2021, PG&E submitted Advice Letter 6361-E submitting for Commission approval the Second Restatement of the Charter for the DCISC. Advice Letter 6361-E was approved and made effective as of November 10. 2021.

At the October 19-20, 2021 public meeting the Committee Members discussed the development of a process to develop a scope of post-shutdown activities. held a discussion concerning revising the scope of the Committee"s post-shutdown activities.

On December 14, 2021, PG&E submitted to the CPUC its Application in the 2021 Nuclear Decommissioning Cost Triennial Proceeding (2021 NDCTP) to provide a forum for review of PG&E"s updated nuclear decommissioning cost studies and ratepayer contribution analyses in support ofrequests to fully fund nuclear decommissioning master trusts (NDTs) to the level needed to decommission PG&E"s two nuclear plants, Diablo Canyon and Humboldt Bay Power Plant Unit 3, and to review decommissioning projects completed since the 2018 NDCTP. In its Application PG&E requests no new revenue requirements for customer contributions to the qualified or non-qualified NDTs for funding Diablo Canyon or Humboldt Bay NDTs. The Application presents PG&E* s revisions to the 2018 NDCTP cost estimates and updates the assumptions, cost estimates 1-20 I

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I and schedule associated with Diablo Canyon decommissioning consistent with the terms of the Settlement Agreement in the 2018 NDCTP. The updated 2021 decommissioning cost estimate for Diablo Canyon is $4,059,207,000 (2020$). Cost savings from the 2018 NDCTP settlement include transferring all spent nuclear fuel to dry cask storage at the ISFSI after 3.25-years of cooling in the spent fuel pools (contingent on receipt ofregulatory approval). The 2021 NDCTP reflects PG&E's current plans to execute Diab lo Canyon decommission using a hybrid approach, with PG&E acting as general contractor until all fuel is in dry storage and large-scale demolition begins, at which time PG&E would step into an oversight role. The assigned administrative law judge has 18 months to issue a Proposed Decision in the 2021 NDCTP after which the CPUC will vote on a final decision.

At its February 15-16, 2022, public meeting the Committee Members held a discussion of plans for the post-shutdown role of the DCISC including revising the scope of post-shutdown committee activities and the engagement of a technical consultant to assist in the review of decommissioning and spent fuel management issues. The Members discussed and received public comments from the public and representatives of non-governmental organizations concerning the Committee's post-shutdown role. The Committee Members also reviewed the draft Post-Shutdown Phases and Timeline which is intended to supplant the previously developed DCISC Post-Shutdown Matrix, and reviewed a sample Post-Shutdown Future Open Items List to be developed to identify activities which will necessarily continue after the plant ceases to generate electricity. Copies of these documents are included in Volume II as Exhibit H.2.

On May 23, 2022, the Cabinet Secretary in the Office of California Governor Newsom, Ms: Ana Matosantos, wrote to the Honorable Jennifer, Granholm, U.S. Secretary of Energy, with reference to Diablo Canyon's planned retirement to suggest adjustments to the April 2022 Guidance issued by the Department of Energy (DOE) to the Civil Nuclear Credit Program, a program to preserve existing U.S. nuclear reactor operation, to delete provisions from that Program related to the exclusion from the Program ofreactors that recover more than 50 percent of their costs from cost-of-service regulations, clarifying that operating losses include costs not recovered through cost-of-serve ratemaking, and including grid reliability and support for state clean energy goals as well as emissions reductions as rationale for extending operation of nuclear power plants. The DOE responded and solicited public comment on whether the Guidance should be revised.

On June 28, 2022, PG&E requested a 75-day extension from the July 5 deadline to submit an application under the Civil Nuclear Credit Program to collect and analyze information in preparation to apply for funding under the Program.

On June 30, 2022, the DOE issued updated Guidance which removed the exclusion from the Program of reactors that recover more than 50 percent of their costs from cost-of-service ratemaking and extended the previous deadline of July 5, 2022, for utilities to submit certifications for application for the Civil Nuclear Credit Program to September 6, 2022.

At the June 22-23, 2022, public meeting the Committee continued the discussion and receipt of public comments regarding its post-shutdown role and the revisions of post-shutdown activities.

At that meeting the Committee Members approved a Scope of Services for the engagement of a 1-21

technical consultant on an ad hoc basis to assist in the review of spent fuel, decommissioning and regulatory issues.

Although outside of this Annual Report period, on July 5, 2022, PG&E representatives announced that PG&E would submit an application for funding under the Civil Nuclear Credit Program.

The DCISC recognizes its commitment now and in the future under the Second Restatement of its Charter to continue to monitor and report on safety of operations at Diablo Canyon, including reviewing any effect of decommissioning-related activities on those operations while the plant continues to generate electricity and after cessation of generation operations until all spent fuel has been transferred from the spent fuel pols to the ISFS at the plant site. The DCISC will continue to provide information to the public and to the Governor, the California Energy Commission, the California Attorney General and to the CPUC on developments which may have an impact on safety of operations at Diab lo Canyon.

l. 7 COVID-19 Pandemic During the period of the 32nd Annual Report, the DCISCs operational safety review activities continued and were note significantly by occasional compromises created by the COVID-19 pandemic.

During the period of this Annual Report Members and Technical Consultants resumed fact-finding visits to visit the plant in person. During the period of this Annual Report the Committee continued with each of its previously scheduled activities,

. occasionally using teleconference and web-based applications as required to ensure adherence to social distancing and Diablo Canyon access restriction protocols and guidance provided by the San Luis Obispo Health Officer which were strictly observed at all times. The October 2021 and the February and June 2022 public meetings were all conducted as a hybrid meeting, in person in Avila Beach, California but with a virtual component that allowed participating in real time through a Zoom webinar facilitated by AGP Video. The Committee has investigated the measures taken by Diablo Canyon to protect plant personnel from COVID-19 and to continue the safe operation of the power plant and reports of its investigations are contained in this Annual Report (Exhibits 8.3, 8.6, 8.9, D.3, D.6 and, D.9).

1.8 Documents Provided to the DCISC The Second Restated Charter provides that the DCISC shall have the right to receive on a regular basis specified operating reports and records of Diablo Canyon, as well as such other reports pertinent to safety as may be produced in the course of operations and may be requested by the Committee. Over the past 31 years, thousands of PG&E and Nuclear Regulatory Commission documents (relating to both historical and current operations) have been provided to the DCISC. Document lists for this annual report period are shown in Volume II, Exhibit A.

1.9 Documentation of DCISC Activities DCISC activities and meetings are documented for public information in several ways as described below. The Committee*s documents are available to the public through the Reference Department at the California Polytechnic University (Cal Poly) R.E. Kennedy Library in San Luis Obispo, California.

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I The DCISC's Annual Report, covering the period July 1 through June 30, is a comprehensive description of Committee activities throughout the period. The report is published in two volumes and in compact disk format and is made available on the Committee website (www.dcisc.org) and is provided to local San Luis Obispo city and county public libraries and to any interested persons.

Minutes of each public meeting are contained in the Annual Report in Exhibits 8.3, 8.6, and 8.9.

Reports of DCISC visits to the Diablo Canyon Power Plant are contained in the Annual Report in Exhibits D. l through D.9.

An informational video concerning its history, role and responsibility, appointment of members and operation of the Committee is available on the DCISC website at www.dcisc.org.

All public meetings during this annual report period, were webcast in real time and later cablecast over the San Luis Obispo local government access television channel, Channel 21, and are available online at all times through indexed, archived streaming video at the link provided on the Committee's website to www.slo-span.org. DCISC issues press releases before and on occasion after its public meetings concerning topics it believes to be of particular interest.

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2.0 PUBLIC MEETINGS During its July 1, 2021 - June 30, 2022, reporting period, the Diablo Canyon Independent Safety Committee (DCISC) held three two-day Public Meetings in the vicinity of the plant and remotely by Zoom. There were no public tours ofDiablo Canyon Power Plant (DCPP) as part ofits public outreach program this period due to the COVID-19 pandemic.

2.1 Public Meetings During this reporting period, the DCISC heard presentations from PG&E on DCPP activities and from Committee Members and Consultants on Committee activities and provided the opportunity for public input at the following DCISC public meetings:

October 19-20, 2021, Avila Beach, CA and remotely by Zoom Public Meeting February 15-16, 2022, Avila Beach, CA and remotely by Zoom Public Meeting June 22-23, 2022, Avila Beach, CA and remotely by Zoom Public Meeting Minutes of the meetings are located in this report as described below. Copies of the Committee"s Annual Reports are located in the Library Reference Department at the California Polytechnic State University at San Luis Obispo, California. Each meeting is streamed live on the internet on www.slospan.org and shown at various later times on one of the local public access television channels.

2.1. l October 19-20, 2021 Public Meetings A Notice of Meeting (see Volume II, Exhibit B. l) was published in the local newspaper and was mailed to the media and those persons on the Committee's service list (see Volume II, Exhibit B. I 0). The meeting agenda is shown in Volume II, Exhibit B.2, and minutes of the meeting are included in Volume II, Exhibit B.3.

2.1.2 February 15-16, 2022 Public Meetings A Notice of Meeting (see Volume II, Exhibit B.4) was published in the local newspapers, along with several display advertisements, and was mailed to the media and those persons on the Committee's service list (see Volume II, Exhibit 8.10). The meeting agenda is shown in Volume II, Exhibit 8.5, and minutes of the meeting are included in Volume II, Exhibit 8.6.

2.1.3 June 22-23, 2022 Public Meetings A Notice of Meeting (see Volume II, Exhibit B. 7) was published in the local newspapers, along with several display advertisements, and was mailed to the media and tho~e persons on the Committee's service list (see Volume II, Exhibit B. 10). The meeting agenda is shown in Volume II, Exhibit 8.8, and minutes of the meeting are included in Volume II, Exhibit B.9.

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I 3.0 NUCLEAR REGULATORY COMMISSION (NRC)

ASSESSMENTS AND ISSUES This section of the DCISC Annual Report describes the DCISC review of PG&E's interface with the US Nuclear Regulatory Commission (NRC). The NRC is the Federal regulatory agency charged with assuring the safety and security of domestic nuclear power plants; by agreement with the State, NRC also performs these functions for the State of California. As regulator, the NRC employs two full-time Resident Inspectors at the plant (and other specialist inspectors at its US headquarters and regional locations), performs and reports on its inspections at DCPP on matters of nuclear safety and security, investigates significant plant events, maintains a set of plant performance indicators, and performs an annual assessment of DCPP regulatory performance which it reports at a public meeting in the plant vicinity. The NRC also must approve significant changes, additions and deletions to plant designs, procedures and Technical Specifications.

PG&E is required to submit routine, periodic reports to the NRC on selected activities and submit special reports when triggered by off-normal plant incidents, events or occurrences.

The DCISC monitors the aforementioned activities and resulting documents in the following ways:

( l) receipt and review of correspondence and reports between PG&E and the NRC, (2) on-site review (at fact-finding meetings at the plant) of selected NRC inspections, investigations and reports, (3) meetings with the NRC Resident Inspectors, and (4) presentations by PG&E and the NRC Resident Inspectors at DCISC public meetings on NRC matters.

3.1 Summary of License Event Reports 3.1.1 Discussion and Required LERs License Event Reports (LERs) are reports required of the nuclear power plant licensee by Nuclear Regulatory Commission (NRC) regulations when an off-normal event occurs. These events include operations or conditions outside of or in violation of station Technical Specifications (TS), procedures or NRC regulations. Events are to be promptly reported by telephone and by written report within 60 days of the event or initial knowledge of the event.

Voluntary LERs are submitted for events, which NRC should know about, or are significant but are not specifically required by NRC. Each of these reports is reviewed in DCISC public meetings and is made available to each DCISC Member and Consultant.

The LER is the responsibility of the Licensee, in this case PG&E. Therefore, it is the Licensee who makes the determination of the level of risk or significance to safety of the event. The NRC has a Significance Determination Process, which sets forth its rules for making these determinations; however, events may be complex or may not easily fit the rules. The NRC may concur or it can question or challenge the Licensee* s determination. Discussions or meetings may be required to reach understandings between the parties.

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There were two LERs reported during this reporting period. This is good performance.

1. Unit 2 LER 2021-001-00 was submitted on 9/20/2021, which documented that Emergency Diesel Generator (EOG) 2-3 operated at less than the required Technical Specification minimum frequency when started in automatic. Manual operation was not affected.

Subsequent Engineering evaluation determined that the EDG had remained capable of performing its safety function.

2. Unit 2 LER 2021-002-00 was submitted on 12/14/2021, which documented that the Unit 2 reactor was manually tripped on October 15, 2021, in response to increasing water level in a secondary-side feed water heater. Following shutdown of Unit 2, the feed water heater was subsequently repaired, and Unit 2 was returned to service.

The DCISC received the LERs in the monthly document packages for review, and DCPP reported on the two LERs at the DCISC public meetings, and DCPP's corrective action, as submitted in the LER submittal to NRC, was determined to be satisfactory by the DCISC.

3.1.2 Special Report LERs There were no special LERs submitted by DCPP during the reporting period.

3.1.3 Voluntary LERs There were no voluntary LERs during this period.

3.1.4 Reactor Trips Reported in LERs During the reporting period, there were no automatic reactor trips and one manual reactor trip reported in the above LERs. In the past five DCISC reporting periods the following numbers of trips have occurred:

Reporting Period 2017/2018 2018/2019 2019/2020 2020/2021 2021/2022 Number of Trips Automatic Manual 0

0 1

0 0

0 0

1 0

1 The number of reactor trips continues to be commendably low.

3.1.5 Other Reports to NRC There were no other significant reports made to NRC.

3.1.6 LER Trends 3-2 I

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I The following table depicts the LER history for DCPP for the last five DCISC reporting periods:

Time Period 711117 - 6/30/18 7/1/18 -6/30/19 7/1/19 - 6/30/20 711120 - 6/30/21 7 /1/21 - 6/30/22 This is good regulatory performance.

Number of LERs Submitted I.

I 2

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3.1.7 DCISC Evaluation and Conclusions The DCISC recognizes that off-normal events will occur in any large complex system. The goal is to identify them and understand them and take action to minimize the consequences and likelihood of any significant increase in risk. The design basis for nuclear power plants involves defense-in-depth.

This recognizes that in real systems, unanticipated events will occur, so protective systems are designed to provide protection even if systems do not always perform as anticipated. For this reason, it is important to investigate events and to share information about them with other plants. DCPP's performance in regard to LERs was good - two LERs.

DCPP's operations resulted in two LERs reported during the current (July 1, 2021 - June 30, 2022) reporting period. This is good performance.

3.2 NRC Inspection Reports and Enforcement Actions I

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The NRC performs inspections at each nuclear power plant. The purpose is to determine how well the plant personnel are implementing and following NRC regulations, plant Technical Specifications, and other requirements, procedures, or commitments. Generally, better regulatory performance results in fewer inspections. NRC meets with the nuclear plant operator twice per year to review plant safety performance under the NRC Reactor Oversight Process (see Section 3.4 below). These meetings are usually open to the public.

Inspections are performed by the plant Resident NRC Inspectors, inspectors from the NRC Region Office, experts from other NRC organizations, and NRC consultants. The bulk of inspections are routine, announced visits focusing on one or more specific areas of operation such as As Low As Reasonably Achievable (ALARA) radiation dose minimization program, maintenance, chemistry, security, operator examinations, or corrective actions. Special inspections are often made for investigation into previous events affecting plant safety and into special programs, such as NRC Generic Letter 89-10, Testing of Motor-Operated Valves.

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Each inspection usually concludes with an exit meeting with PG&E personnel, followed by a written inspection report. Inspections can result in the following categories of findings:

Unresolved Items are items for which information is not yet available or awaiting licensee response or action.

Deviations are variances from NRC regulations and/or licensee procedures or other requirements or commitments, which are not as severe as outright violations.

Findings are NRC-identified or self-revealing issues of concern associated with a performance deficiency by the licensee.

Concerns, typically including more than one individual weakness in a single area, are to alert the licensee to situations which could become violations if not corrected.

Non-cited Violations are violations for which NRC credits the licensee for identifying the violation and/or for prompt, effective corrective action completed before or taken during the inspection. These are usually non-recurring, non-safety-significant items.

Violations of NRC regulations, plant Technical Specifications, and other commitments, procedures, etc. require a formal response and corrective action. Violations carry four severity levels as described in Section 3.3, NRC Enforcement Actions and below.

Fewer violations generally mean better performance. Some in the industry believe having a significant number of non-cited violations indicates an effective, aggressive regulatory program, meaning the licensee quickly finds and corrects its own problems/violations rather than the NRC identifying them.

NRC considers items not in compliance with its regulations or with the licensee's commitments or procedures to be violations. Corrective action is required for all violations. NRC identifies four severity levels for violations.

Level I is the most severe, representing the most significant regulatory concern which usually involves actual or high potential impact on the safety of the public. Level IV violations are more than minor concern and should be corrected so as to prevent a more serious concern. Civil penalties (monetary fines) are usually imposed for Level I and II violations, are considered for Level III, and usually not imposed for Level IV violations. Most low-level violations are reported as Non-cited Violations provided the licensee places the violation into its corrective action program and provided the violation is not willful or repetitive. NRC has increased its scrutiny of corrective action programs. The categorization of violations in this report follows NRC's actual classification in each notice of a violation.

NRC issued the following inspection reports during this reporting period:

Security Baseline Inspection Report (2021-401, 7/21/2021)

Temporary Instruction 2515/ 194 Report (2021-012, 7/28/2021) 3-4 I

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I Second Quarter 2021 Integrated Inspection Report (2021-002, 8/2/2021)

Security Baseline Inspection Report (2021-405, 8/4/2021)

Design Basis Assurance Inspection (Programs) Report (2021-405, 8/5/2021)

Third Quarter 2021 Integrated Inspection Report (2021-003, 11/3/2021)

Security Baseline Inspection Report (2021-404, 1/23/2022)

Fourth Quarter 2021 Integrated Inspection Report (2021-004, 2/3/2022)

Security Inspection Report (2021-420, 3/31/2022)

First Quarter 2022 Integrated Inspection Report (2022-001, 5/5/2022)

These inspection reports (plus assessment letter) are typical of recent previous periods for DCPP.

Cross-cutting performance appears good with no cross-cutting themes identified by NRC. The DCISC receives and reviews all NRC inspection reports. Additionally, DCISC members regularly discuss NRC inspection findings with Resident Inspectors during Fact-Finding Meetings.

3.2.2 DCISC Review of Trends of Violations and NRC-Identified Issues Non-Cited Violations (NCVs) are usually items of very low safety significance (called

• • Green).

All NCVs are entered into the DCPP Correction Action Program (CAP), and a Notification is issued. Notifications are reports used to identify and document plant problems in the CAP. The NCVs are reviewed for their safety significance, and cross-cutting issues. DCPP will perform an Apparent Cause Evaluation (ACE) for the NCVs as determined by plant director-level management.

NRC Non-Cited Violations (NCVs)

NCVs are violations of NRC regulations, which have very low safety significance, and, as such, are not **cited" as violations by NRC.

NRC violations are included in the DCPP CAP Trending Program and are not trended separately.

An Event Trend Record (ETR) is issued for each NCV associated with an AT-NCV AR (A-type Non-Cited Violation Action Request). Periodic evaluation of the ETRs is undertaken to identify adverse trends.

NRC issued the following nine Non-Cited Violations and one Finding during the reporting period:

(Note: the following terms are used:

NCV = NRC Non-Cited Violation SLIV = NRC Safety Level IV Violation FIN= NRC Finding Green = NRC considers very low safety significance PG&E-Ident(fied = violation was first found by PG&E and reported to NRC C-C Aspect= NRC cross-cutting category for the violation) 3-5

Green Non-Cited Violation associated with the documented level of detail for a scaffolding evaluation performed in support of maintenance on a diesel generator. (A Cross-cutting aspect of H. l, '*Inadequate Procedure,'" was assigned to this violation)

Green Finding associated with the inadequate use of industry operating experience associated with environmental corrosion of outdoor piping (No Cross-Cutting aspects were assigned to this violation.)

Green Non-Cited Violation associated with a Containment Spray Drain Valve misposition that occurred during refueling outage I R22. (A Cross-cutting aspect of H.12,

--Avoid Complacency, was assigned to this violation.)

Green Non-Cited Violation associated with sequence of testing associated with the carbon dioxide fire suppression system. (No Cross-cutting aspects were assigned to this violation.)

There have been three violations (excluding security-related violations) of more than minor significance since the last DCISC reporting period:

I. Green (Very Low safety significance) Non-Cited Violation (NCV) - Moisture and buildup on the ASW pump 1-1 motor internal windings was not promptly corrected, which resulted in a challenge to the operability of the ASW motor.

(Cross-Cutting Aspect H.6, "Design Margins")

2. Green (Very Low safety significance) Non-Cited Violation (NCV) - The station did not adequately scope maintenance verification testing for tuning of the diesel generator 2-3 fuel system, which resulted in a low steady state frequency during a diesel start.

(Cross-Cutting Aspect H.5, "Work Management")

3. Green (Very Low safety significance) Non-Cited Violation (NCV) - Procedure for responding to a high water level in a feedwater heater contained guidance that could have led to delays in actions taken by control room personnel in response to an identified feedwater tube leak.

(No Cross-cutting aspect was assigned to this violation)

The history of violations for this and the previous four DCISC reporting periods is as follows:

DCISC Number of Violation Severity Level Violations Re:Qorting Period Ins12ections ill IV Non-Cited Total 7 /l /1 7 - 6/3 0/ l 8 10 9

9 7 /l /18 - 6/3 Oil 9 5

9 9

7/1/19 - 6/30/20 6

6 6

7/1/20 - 6/30/21 8

4 4

7/1/21 -6/30/22 6

3 3

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I There were no NCVs in the last four quarters that had four or more common Cross-cutting Aspects.

This means that the NRC does not need to closely monitor any particular Cross-cutting aspects, and that DCPP is not close to receiving an NRC Substantive Cross-cutting Issue.

3.2.3 DCISC Evaluation and Conclusions The numbers of NRC inspections in prior periods had been consistent at about ten, until the last three periods for which there were six, eight, and six respectively ( excluding security).

This relatively low number is a direct result of good regulatory performance as measured primarily by NRC Performance Indicators (see Section 3.5 below). The DCISC will continue to follow NRC violations and trends.

The DCISC received reports and heard presentations by DCPP on each non-cited violation and finding at its public meetings and has reviewed each cited violation and DCPP's corrective actions, where applicable. DCPP corrective actions appeared adequate. There were no individual items of significance to warrant DCISC recommendations or actions.

All of DCPP's three NCVs and two License Event Reports were classified by the NRC as having "very low safety significance (Green)." The DCISC reviewed these violations and DCPP's respective corrective actions and concluded they were satisfactory.

3.3 NRC Performance Evaluations The Nuclear Regulatory Commission (NRC) inspection, assessment, and enforcement programs for commercial nuclear power plants take into account improvements in the performance of the nuclear industry over the past 25 years and improved approaches of inspecting and assessing safety performance at NRC-licensed plants.

The NRC Revised Reactor Oversight Process (RROP) monitors licensee performance in three broad areas (called strategic performance areas):

1. Reactor Safety (avoiding accidents and reducing the consequences of accidents if they occur)

2. Radiation Safety (protecting plant employees and the public during routine operations)

3. Safeguards (protecting the plant against sabotage or other security threats).

The process focuses on licensee performance within each of*'Seven Cornerstones" of safety in the three areas:

Reactor Safety

• Initiating Events

• Mitigating Systems Radiation Safety

• Occupational

• Public 3-7 Safeguards

• Physical Protection

• Barrier Integrity

• Emergency Preparedness To monitor these Seven Cornerstones of safety, the NRC uses two processes that generate information about the safety significance of plant operations:

1. Inspections

2. Performance Indicators Inspection findings are evaluated according to their potential significance for safety, using the significance determination process, and assigned colors of GREEN, WHITE, YELLOW, or RED.

GREEN findings are indicative of issues that, while they may not be desirable, represent very low safety significance.

WHITE findings indicate issues that are of low to moderate safety significance.

YELLOW findings are issues that are of substantial safety significance.

RED findings represent issues that are of high safety significance with a significant reduction in safety margin.

Performance Indicator data are compared to established criteria for measuring licensee performance in terms of potential safety. Based on prescribed thresholds, the indicators will be classified by color representing varying levels of performance and incremental degradation in safety: GREEN, WHITE, YELLOW, or RED.

GREEN indicators represent performance at a level requiring no additional NRC oversight beyond the baseline inspections.

WHITE corresponds to performance that may result in increased NRC oversight at the Resident Inspector or Regional level.

YELLOW represents performance that minimally reduces safety margin and requires even more NRC oversight at the NRC Region level.

RED indicates performance that represents a significant reduction in safety margin but still provides adequate protection to public health and safety. NRC response at the Agency level could include public meeting, utility-developed performance improvement plan, and/or special inspection teams.

The oversight process integrates performance indicators and inspections so the NRC can reach objective conclusions regarding overall plant performance. The NRC uses an Action Matrix to determine in a systematic, predictable manner which regulatory actions should be taken based on a licensee's performance. The NRC's actions in response to the significance (as represented by the color) of issues will be the same for performance indicators as for inspection findings. As a 3-8 I

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I licensee*s safety performance degrades, the NRC will take more and increasingly significant action, which can include shutting down a plant, as described in the Action Matrix.

The NRC Performance Indicators (Pis) and Most Significant Inspection Findings Categorization for DCPP through the second quarter 2020 are depicted in Table 3.1 through 3.4 at the back of Section 3.0.

The NRC inspection program uses a risk-informed approach to select areas of the plant to inspect within each cornerstone. The selection is based on potential risk, past operational experience, and regulatory requirements.

Each calendar quarter, NRC inspectors and the regional office review plant performance indicators and inspection findings. Each year, NRC regional and headquarters offices make a final review, to include a more detailed assessment of plant performance over the 12-month period, preparation of a performance report, and preparation of a six-month inspection plan. The report is sent to each plant and discussed in a public meeting.

NRC Annual Assessment Letter 2022 The following paragraphs are excerpts from the NRC's most-recent annual assessment letter for DCPP issued on March 2, 2022:

The Nuclear Regulatory Commission (NRC) has completed its end-of-cycle performance assessment of Diab lo Canyon Power Plant, Units I and 2, reviewing performance indicators (Pls),

inspection results, and enforcement actions from January 1, 2021 through December 31, 2021.

This letter informs you of the NRC' s assessment of your facility during this period and its plans for future inspections at your facility. The NRC concluded that overall performance at your facility preserved public health and safety. The baseline inspection program was completed at your facility as defined in Inspection Manual Chapter 2515, --Light-Water Reactor Inspection Program -

Operations Phase.**

The NRC determined the performance at Diablo Canyon Power Plant, Units 1 and 2 during the most recent quarter was within the Licensee Response Column, the highest performance category of the NRC's Reactor Oversight Process (ROP) Action Matrix, because all inspection findings had very low safety significance (i.e., Green), and all Pls were within the expected range (i.e., Green).

Therefore, the NRC plans to conduct ROP baseline inspections at your facility.

The enclosed inspection plan lists the inspections scheduled through December 31, 2023. The NRC provides the inspection plan to allow for the resolution of any scheduling conflicts and personnel availability issues. Routine inspections performed by resident inspectors are not included in the inspection plan. The inspections listed during the last twelve months of the inspection plan are tentative and may be revised. The NRC will contact you as soon as possible to discuss changes to the inspection plan should circumstances warrant any changes.

In response to the COVID-19 public health emergency (PHE), the NRC adjusted inspection plans and schedules in order to safeguard the health and safety of both NRC and licensee staff while still 3-9

effectively implementing the ROP. While the PHE continues, overall conditions throughout the country support performance of our inspection and oversight activities to return to normal onsite presence by our resident and region-based inspectors and completion of nominal baseline inspection samples. We continue to monitor site-specific conditions and as discussed in our November 2, 2021 memo, --Implementation of Inspection Programs Following Re-Entry from the Public Health Emergency for the Reactor Safety Program** (ML21295A302), it may be necessary to alter how and when we perform our inspection and oversight activities as we balance the importance of protecting the health and safety of our staff with the need to conduct effective oversight that supports the NRC's critical safety mission. For inspections requiring extensive coordination with offsite organizations, such as evaluated emergency preparedness exercises, NRC guidance and frequently asked questions for security and emergency preparedness can be found here: https://www.nrc.gov/about-nrc/covid-19/securityep/. Similarly, the NRC has developed guidance if force-on-force inspections cannot be completed as scheduled due to an emergency, such as the COVID-19 PHE. These changes help ensure the health and safety of both NRC and licensee staff while maintaining the NRC's important safety and security mission during the COVID-19 PHE. The attached inspection plan is accurate on the date of issuance but remains subject to change based on approval of potential exemption requests or other changes needed due to changing conditions in the COVID-19 PHE. NRC staff will contact your appropriate regulatory affairs staff in order to coordinate inspection planning and scheduling.

In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 2.390 of the NRC's

• • Rules of Practice," a copy of this letter will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

The DCISC understands this to mean acceptable regulatory performance and no increased inspections above baseline. The DCISC will continue to follow this area closely.

The DCISC concurs with the NRC assessment of DCPP's having acceptable regulatory performance and will continue monitoring DCPP regulatory performance.

3.4 DCISC Meetings with NRC Resident Inspectors The DCISC held nine meetings with the NRC Resident Inspectors (NRC Rls) as follows:

1. July 14-15, 20il Fact-finding Meeting The participants discussed the following topics:

Recent failure of Auxiliary Saltwater (ASW) Pump 1-1 and an associated emergency License Amendment Request to change the plant Technical Specifications. The pump motor failed during a routine start on July 5, placing the plant into a 72-hour Limited Condition for Operation to return the pump to service or otherwise begin shutdown of the unit. Replacement of the motor was a complex evolution due primarily to its location deep inside the Intake Structure, and work planners estimated that the time 3-10 I

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I required to replace the motor could exceed the 72-hour window if any problems arose that added to the scope of the work. Given the inherent redundancy of the ASW system and the alternate heat sinks available to the plant, DCPP proposed to the NRC that a one-time extension of the 72-hour window to 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br /> would be preferable to the risk of initiating a plant shutdown. The NRC evaluated the request, determined that there was a reasonable assurance that the health and safety of the public would not be endangered by the proposed extension, and approved the request on July 8 (NRC ADAMS accession number ML2 l l 88A245). DCPP personnel successfully completed the motor replacement shortly thereafter, using approximately 76 hours8.796296e-4 days <br />0.0211 hours <br />1.256614e-4 weeks <br />2.8918e-5 months <br /> to complete the work. The NRC and the FFT both considered that DCPP appropriately managed the pump replacement; however, the Cause Evaluation for the ASW Pump motor failure warranted further review following its completion.

The FFT inquired with the NRC inspectors regarding a question received by the DCISC from the office of a local Congressman. The question regarded if and how the NRC viewed aging equipment and whether alternative standards existed for what might qualify for a waiver from the NRC as the plant nears closure. The NRC inspectors confirmed the FFT's previous understanding that the NRC did not allow any waivers or exemptions from its regulatory requirements solely because the plant was nearing closure. Regardless of the amount of time remaining until closure, any waivers or exemptions to the regulations desired by DCPP were required to be submitted to the NRC for their review and approval along with an analysis demonstrating that there was no reduction in safety due to the proposed change. (This explanation will be provided by the DCISC to the Congressman* s office.)

2. August 18-19, 2021 Fact-finding Meeting DCISC history and role Auxiliary Saltwater System Pump emergency license amendment Emergency Diesel Generator fuel oil leak Tin whiskers Upcoming Emergency Exercise on September 15, 2021

3. September 13-14, 2021 Fact-finding Meeting Recent NRC inspection results and concerns NRC closure of concerns related to open phase electrical vulnerabilities Plant staffing

4. November 16-1 7, 2021 Fact-finding Meeting DCISC history and role DCISC FFT agenda for this meeting Seismic workplace safety Adequacy of DCPP personnel to operate DCPP safely Feedwater heater forced outage Emergency Diesel Generator recent License Event Report

5. December 7-8, 2021 Fact-finding Meeting 3-11

NRC Inspector staffing Unit 2's recent forced outage to repair a Feedwater Heater leak Emergency Diesel Generator 2-3's fuel oil leak that occurred in June 2021 Recent NRC inspection results and concerns

6. January 11-12, 2022 Fact-finding Meeting DCISC history and role DCISC FFT agenda for this meeting Seismic workplace safety Adequacy of DCPP personnel to operate DCPP safely Feedwater heater forced outage

7. March 23-24, 2022 Fact-finding Meeting NRC Inspector staffing Recent NRC inspection results and concerns.

8. April 12-13, 2022 Fact-finding Meeting DCISC Agenda for this Fact Finding meeting Outage l R23 Inspections Infrequent Operations and Evolutions High Winds occurring at the time of the meeting Fuel Handling Equipment problems Residual Heat Removal System relief valve replacement error

9. May 18-19, 2022 Fact-finding Meeting NRC Office of Inspector General's report on the NRC's oversight of the Auxiliary Feedwater System at DCPP NRC response to the Office of Inspector General's report Resident Inspector staffing at DCPP Recent inspection findings 3.6 DCISC Conclusions and Recommendations

==

Conclusions:==

The DCISC received regular reports on the Nuclear Regulatory Commission (NRC) Performance Indicators, DCPP License Event Reports (LERs) sent to NRC, and NRC Inspection Reports and Enforcement Actions (violations) at each of its Public Meetings as well as copies of these documents throughout the reporting period. The DCISC investigated selected reports at its fact-finding meetings. The number of LERs has decreased down to two during this one-year period. This represents good regulatory performance.

The Committee notes that, although the NRC concluded that DCPP operated acceptably, it identified three Non-cited Violations and received two License Event Reports of "very low safety significance." This appears to be an improvement from most previous periods.

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I The DCISC will continue to review DCPP's NRC regulatory performance during the next reporting period, paying particular attention to the number and significance of DCPP violations and LERs.

Recommendations: None 3-13

Table 3.1 Second Quarter 2022 NRC Performance Indicators for Diablo Canyon Power Plant Unit Unit 1

2 Unplanned Scrams per 7000 Critical Hrs Unplanned Power Changes per 7000 Critical Hrs Unplanned Scrams with Complications Safety System Functional Failures Mitigating Systems Performance Index, Emergency AC Power System Mitigating Systems Performance Index, High Pressure Injection System Mitigating Systems Performance Index, Heat Removal System Mitigating Systems Performance Index, Residual Heat Removal System Mitigating Systems Performance Index, Cooling Water Systems Reactor Coolant System Activity Reactor Coolant System Leakage Drill/Exercise Performance ERO Drill Participation Alert & Notification System Occupational Exposure Control Effectiveness RETS/ODCM Radiological Effluent 3-14 I

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I The DCISC will continue to review DCPP's NRC regulatory performance during the next reporting period, paying particular attention to the number and significance of DCPP violations and LERs.

Recommendations: None 3-13

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I 4.1 Conduct of Operations 4.1.1 Overview and Previous Activities During the previous reporting period, the DCISC reviewed the following topics related to the Conduct of Operations at seven Fact-finding Meetings:

Operations Misposition Issues (Equipment Status Control)

Slight Rise in Unit l Power Operation Prior to a Curtailment Operational Decision-Making Program Low Temperature Overpressurization Protection System Event Winter Storm Response Reactivity Management Update Operator Concerns and Issues The DCISC concluded the following during the previous reporting period:

DCPP Operations developed and effectively implemented a Status Control Action Plan for improvement on component mispositioning errors. DCPP's Operational Decision-Making (ODM) Program procedure and five OD Ms reviewed appeared appropriate. DCPP's actions taken in response to an unexpected actuation of the Low Temperature Overpressure Protection System as well as the Apparent Cause Evaluation and corrective actions appeared appropriate. Although there were no big winter Pacific Ocean storms during the winter of 2020-2021, DCPP had available procedures and equipment, which had proved effective in the past when dealing with storm surge and kelp debris. DCPP has an effective Reactivity Management Program, which ensures conservative reactivity management by promoting a reactivity-conscious culture. With its Retention Plan, DCPP anticipated having enough operators to safely operate until power operations cease in 2025.

4.1.2 Current Period Activities During the current period, the DCISC received presentations on the conduct of operations at five Fact-finding Meetings. The following topics were reviewed:

Observation of Operations Turnover and Focus Meeting Chemistry Update Trends in Plant Status Control Events Operator Rounds Procedures and Experience Operability Determination Program Inadvertent Boric Acid Addition Event Observation of Operations Turnover and Focus Meeting (Volume II, Exhibit 0.1, Section 3.1)

The DCISC observed two Shift Managers conducting their turnover briefing using a standard checklist provided in accordance with DCPP Administrative Procedure OPl.DC37, **Plant Logs,"

4.1-1

a copy of which was provided to and reviewed by the DCISC. Additionally, the Shift Managers maintained a notebook divided into sections corresponding to items on the checklist ( crew member qualifications/assignments, work activity schedules, test schedules, clearances in place and planned, logs, etc.). The turnover briefing was well structured and facilitated the efficient transfer of a significant amount of information between the Shift Managers.

One non-routine item concerning the acceptability of data taken during a surveillance test on the previous day was discussed extensively. The two Shift Managers worked together to ensure that a path forward was established to resolve the issue in a timely manner.

Additionally, the DCISC remotely observed the 0700 Operations Focus Brief. Approximately 20 personnel from various departments (Operations, Maintenance, Engineering, Chemistry, Radiation Protection, Security, Fire, etc.) participated in the meeting which was held via voice-only remote meeting. The Shift Manager, led the group through the meeting agenda which included:

Safety moment, desired outcomes, plus/deltas from last meeting Shift Manager briefing (work plans, plant issues, ownership of issue resolution)

Security Watch Commander briefing Radiological Protection briefing Integrated risk and mitigations for the day's major activities Work Manager briefing (priority work and scheduled completions, clearances, work challenges, probabilistic risk profile)

Other operational focus items The meeting was observed to be orderly with relevant information shared in a concise and professional manner.

Shift Manager turnover activities were observed to be formal and effective in transferring information between the off-going and oncoming operations staff. The 0700 Operations Focus Brief was found to be well structured with a large amount of relevant information shared in a concise and professional manner.

Chemistry Update (Volume II, Exhibit D.2, Section 3.8)

DCPP measured its performance in Chemistry using the DCPP Chemistry Effectiveness Index (CEI). The CEI is an industry standard performance measure based on an 18-month rolling composite that is reflective of a representative set of primary and secondary chemistry parameters.

The CEI ranges from 0, representing ideal performance, to 100, representing worst performance.

Units 1 and 2 CEis were both near zero and rated Green (industry first quartile). Also, both the Quality Performance Assessment Report ( QP AR) and the Quality Digest rated Chemistry as Green and stable. This was good performance.

DCPP's Chemistry Program was rated Green (Good) with performance in the first industry quartile. This was good performance.

Trends in Plant Status Control Events (Volume II, Exhibit 0.5, Section 3.4) 4.1-2 I

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I The term Plant Status Control Events generally refers to events in which an operator or technician manipulates the wrong component (such as a valve or switch) or places a component in the wrong position. Challenges in the area of plant status control performance became an issue in late 2017 and continued through 2019. As a result, plant status control performance was escalated by Quality Verification to the Station Director in July 2019. Operations developed a Plant Status Control Action Plan to address this performance decline which included a common cause evaluation, increased observations and communications, and a video that was distributed site-wide to demonstrate strong component positioning behaviors. In March 2020, the DCISC found that Operations was working through its Action Plan and would be performing an effectiveness review when it completed the Plan.

In December 2020, the DCISC reviewed the results of the effectiveness review and found it to be satisfactory.

During 2021, the DCISC found that the Operations Department had accomplished a significant culture shift, particularly among operators in the field. Regular observations in the field had reinforced the need for improving procedural usage, second checks, and tagging and clearance implementation. The observation program was performed using procedure OPl.ID9, '*Crew Performance Review," Revision 5, a copy of which was provided to and reviewed by the DCISC along with examples of reports for the performance and results of field observations including the Crew Notebook, Management Review Meeting agenda, and Performance Indicator Dashboard for the B Crew.

Additionally, the DCISC received and reviewed the Operations Performance Improvement Dashboard for October 2021 and found that it indicated good performance for the last 12 months.

The Operations Department also began convening a quarterly Plant Status Control Leadership Team for the purpose ofreviewing plant overall performance in status control at a high level. The DCISC reviewed copies of the agenda and minutes for a Plant Status Control Leadership Team meeting held on November 10, 2021. The meeting included reviews of recent plant status control events, corrective actions, performance indicators, and clearance and tagging events. Overall, the performance indicators showed good performance although there were a few recent issues, primarily in the Chemistry Group and Maintenance Department.

The DCISC also inquired about the status of morale within the Operations Department, and DCPP reported that it was generally good. The department unexpectedly lost eight Non-Licensed Operators (NLOs) within the last year, and as a result, the station had recently hired and started a training class for ten new NLOs in November 2021.

DCPP's corrective actions for past problems in Plant Status Control continue to be effective.

Plant status control performance has improved and was being sustained at a high level.

Operator Rounds Procedures and Experience (Volume II, Exhibit D.6, Section 3.2)

DCPP operator rounds were controlled by Procedure OPl.DC3, **operator Routine Plant Equipment Inspections," Revision 16, July 6, 2021, which was provided to and reviewed by the DCISC. Because of COVID-19 Pandemic restrictions, actual observation of an operator on rounds was not possible, and DCPP's participants remotely described the typical rounds made by operations personnel. A regular round of the Turbine Building 85-foot level was scheduled for the 4.1-3

day of the fact-finding meeting. This round takes about 1-1/2 hours and comprises most equipment on the 85-foot level, which is the lowest level. Using a personal digital assistant as a guide and data recording device, the operator observes and records data such as instrument readings, water or steam leakage, rotating equipment vibration and noise, and general plant conditions. Data outside of specifications is noted, and action initiated based on its importance and particular piece of equipment.

DCPP's Operator rounds procedure and practices appeared satisfactory.

Operability Determination Program (Volume II, Exhibit D.6, Section 3.11)

Evaluations for degraded or non-conforming conditions were governed by DCPP's Operability Determination Program. The process began when a problem was identified, and a notification was made under the Corrective Action Program. The identifier of a problem was responsible for immediately reporting the problem to an Operations Shift Manager (SM). The SM was then responsible for assessing the problem*s impact on operability without delay using guidance contained in the above procedure.

Procedure OM7.ID12, '*Operability Determination," was provided to and reviewed by the DCISC.

It was found to have detailed guidance for the SM to use to determine if reported problems were indicative of degraded or non-conforming conditions affecting the operability of Systems, Structures or Components (SSCs) that were required to be operable by Technical Specifications (TSs), that performed support functions for SSCs required to be operable by TSs, or that were required to support the DCPP Emergency Plan. If a reported problem was found to be a potentially degraded or non-conforming condition, then the procedure required the SM to use conservative decision making in working through a set of detailed questions and criteria to determine if the affected equipment remained operable or should be declared inoperable. If at any time during the evaluation of operability there was not a reasonable expectation that the equipment was operable, then the procedure required the SM to declare the equipment inoperable and take the appropriate actions required for the inoperable equipment.

Additionally, the procedure required the performance of an extent of condition analysis for any equipment declared inoperable to ensure that other similar equipment was not similarly affected.

In cases where the basis for determining operability was not clear, was overly complex, or required compensatory measures to maintain operability, the procedure directed the SM to request a more detailed evaluation by the applicable engineering organization in the form of a Prompt Operability Assessment (POA). The procedure contained detailed guidance for the preparation of POAs, timeframes in which POAs should be completed, and guidance for tracking POAs and reporting the same to senior management. At the time of the DCISCs review, DCPP had no open PO As and no degraded or non-conforming conditions. This was good performance.

DCPP's Operability Determination program appeared to be designed and implemented satisfactorily. There were no open Prompt Operability Assessments, degraded conditions, or non-conforming conditions. This was good performance.

Inadvertent Boric Acid Addition Event (Volume II, Exhibit D.7, Section 3.7) 4.1-4 I

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I The DCISC reviewed an event that occurred on December 21, 2021. Operators on Unit 2 were performing a surveillance test to exercise eves valve FCV-11 0A, the Boric Acid to Blender Isolation Valve, and completed all but a few remaining steps of the procedure.

The first (incomplete) test procedure was set aside, and operators started performing another surveillance test to exercise CVCS valve FCV-11 OB, the Blender to Charging Header Isolation Valve. During the performance of the second test, operators unexpectedly heard beeps from the reactor makeup controller indicating that boric *acid was being added to the RCS. Operators immediately stopped the boric acid addition by closing all open eves valves.

Subsequent analysis of the data concluded that approximately five gallons of boric acid were inadvertently added to the RCS which resulted in a 0.12% decrease in Unit 2 Reactor power level.

All other Reactor parameters remained within normal control bands, and a dilution was later performed to return Reactor power to the desired level. The direct cause of the event was the fact that the two valves being tested were in series, and the failure to properly complete the first test procedure while executing the second test procedure inadvertently placed the plant in a configuration in which both* valves were simultaneously open. The event was reviewed under DCPP's Reactivity Management Program and classified as a --Level 4'" event based on an inadvertent power change of less than 1 % with the Reactor at greater than 5% power. (Reactivity Management events were rated on a scale of 1 to 6, with 1 being the most safety significant.) A Level 4 event was considered a precursor type of event and not in itself oflarge safety significance.

Reviews concluded that the primary cause of the event was the fact that operators failed to recognize that valve manipulations within the first procedure invalidated the initial conditions for the second procedure. Secondary causes were: 1) an inaccurate perception of risk leading to inadequate task preview and pre-job briefing, 2) improper use of human performance tools to evaluate the expected system response given the current system configuration, and 3) inadequate supervisory oversight and pre-job briefing. Corrective actions included removing qualifications from the operators involved in the event and requiring each operator to complete an individual remediation plan before returning to duties. Also, the event and its lessons learned were widely communicated through the station, and the procedures used during the event were enhanced to minimize the potential for recurrence. The event was also recorded as a discretionary Department Level Event in the Performance Improvement System for the Operations Department.

DCPP's actions taken in response to an inadvertent addition of boric acid to the Reactor Coolant System appeared appropriate and consistent with its low safety significance.

4.1.3 Conclusions and Recommendations

==

Conclusions:==

Shift Manager turnover activities were observed to be formal and effective in transferring information between the off-going and oncoming operations staff. A 0700 Operations Focus Brief was found to be well structured with a large amount of relevant information shared in a concise and professional manner.

DCPP's Operator rounds procedure and practices appeared satisfactory, and the Chemistry Program was rated Green (Good) with performance in the first industry quartile. DCPP's corrective actions for past 4.1-5

problems in Plant Status Control continued to be effective, and plant status control performance was being sustained at a high level. The Operability Determination program appeared to be designed and implemented satisfactorily, and actions taken in response to an inadvertent addition of boric acid to the Reactor Coolant System appeared appropriate and consistent with its low safety significance.

Recommendations: None 4.1-6 I

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I 4.2 Conduct of Maintenance 4.2. l Overview and Previous Activities The following are maintenance-related items the DCISC reviewed in the previous reporting period:

Electronic Work Packages Maintenance Department Update Maintenance Rule Program The DCISC concluded the following during the previous reporting period:

DCPP Maintenance performance is generally satisfactory with high performance indicators.

4.2.2 Current Period Activities During the current period, the DCISC reviewed the following topics:

Crane Program Maintenance Rule Program Update Online Maintenance Scheduling Maintenance Department Foreign Material Exclusion Program Crane Program (Volume II, Exhibit D.5, Section 3.5)

The operation and maintenance of cranes is managed by the Maintenance Department. There were six major cranes at the station: two Turbine Building Cranes, two Containment Polar Cranes, one Fuel Handling Area Crane, and one Intake Structure Crane. The Maintenance Department was also responsible for operating and maintaining mobile cranes, of which four were permanently located on site, as well as 22 smaller hoists that were located in various areas around the station.

The two Manipulator Cranes and two Spent Fuel Bridge Cranes that were used for reactor refueling were primarily managed by Operations and Engineering. Most DCPP cranes were in excellent condition having been overhauled and provided with upgrades to drives and controls within the last few years. The only current significant issue was corrosion-related degradation of the Intake Structure crane, and additional maintenance work and controls upgrades were planned for that crane.

4.2-1

Unit 2 Turbine Building Crane The DCPP Crane Group consisted of seven individuals classified as Mechanic Riggers. Mechanic Riggers were qualified through a site training program lasting 30 to 36 months which trained the riggers in both the general requirements of the California Occupational Safety and Health Administration as well as DCPP site-specific requirements for the use of cranes and associated rigging acttv1ttes.

The Mechanic Riggers were the primary individuals responsible for the operation of cranes at DCPP (other than fuel handling), and they also performed most of the required inspection and maintenance activities for cranes and rigging equipment.

There were very few crane features that were directly related to nuclear safety. Rather, the primary nuclear safety concern related to crane operations was the management of loads suspended from cranes such that they could not come in contact with safety-related equipment if a seismic event or other type of failure were to occur during load movement. This concern was addressed by the requirements of procedure MA l.ID 14, '*Plant Crane Operating Restrictions," Revision 30, which provided very detailed requirements for restrictions on load movements over areas were equipment important to safety could be damaged if a load were to be dropped during a seismic event or due to other failures. For example, there were defined areas for the Turbine Building Crane where suspended loads were restricted because the Component Cooling Water Heat Exchangers were located underneath the operating deck. These areas were described in the procedure, detailed on associated drawings, and designated by floor markings as shown below:

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I 4.2 Conduct of Maintenance 4.2.1 Overview and Previous Activities The following are maintenance-related items the DCISC reviewed in the previous reporting period:

Electronic Work Packages Maintenance Department Update Maintenance Rule Program The DCISC concluded the following during the previous reporting period:

DCPP Maintenance performance is generally satisfactory with high performance indicators.

4.2.2 Current Period Activities During the current period, the DCISC reviewed the following topics:

Crane Program Maintenance Rule Program Update Online Maintenance Scheduling Maintenance Department Foreign Material Exclusion Program Crane Program (Volume II, Exhibit D.5, Section 3.5)

The operation and maintenance of cranes is managed by the Maintenance Department. There were six major cranes at the station: two Turbine Building Cranes, two Containment Polar Cranes, one Fuel Handling Area Crane, and one Intake Structure Crane. The Maintenance Department was also responsible for operating and maintaining mobile cranes, of which four were permanently located on site, as well as 22 smaller hoists that were located in various areas around the station.

The two Manipulator Cranes and two Spent Fuel Bridge Cranes that were used for reactor refueling were primarily managed by Operations and Engineering. Most DCPP cranes were in excellent condition having been overhauled and provided with upgrades to drives and controls within the last few years. The only current significant issue was corrosion-related degradation of the Intake Structure crane, and additional maintenance work and controls upgrades were planned for that crane.

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I DCPP's Crane Program appeared to be implemented effectively and lifting and rigging equipment was in good condition. Appropriate procedures were in place to prevent the movement of loads from having an impact upon equipment important to nuclear safety.

Maintenance Rule Program Status (Volume II, Exhibit D.8, Section 3.3)

DCPP's Maintenance Rule (MR) Program is governed by procedure MAl.1D17, --Maintenance Rule Monitoring Program," Revision 34.

This procedure describes how the plant program complies with 10 CFR 50.65, "Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," (referred to as the NRCs "*Maintenance Rule") using the guidance provided in industry document NUMARC 93-01, "Industry Guidelines for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants." The major areas of implementing the program are aligned with NRC Regulatory Guide 1.160, "Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," which endorses NUMARC 93-01 and provides additional provisions and clarifications for complying with 10 CFR 50.65. The DCPP procedure appeared satisfactory.

DCPP's MR Program follows the industry guidance closely and defines major parts of the rule as follows:

(a)( 1) - Defines when a Structure, System or Component (SSC) requires the establishment of additional goals and monitoring to assess that preventative maintenance performance is adequate.

(a)(2) - Defines when an SSC is performance or condition is being effectively controlled through the performance of appropriate preventative maintenance.

(a)(3) - Requires that performance and condition monitoring activities and associated goals, and preventive maintenance activities shall be evaluated at least every refueling cycle.

(a)(4) - Establishes the requirements for plants to assess and manage the potential increase in risk resulting from online maintenance activities. (Not covered in this meeting; risk-based scheduling of online maintenance is regularly reviewed by the DCISC as a separate topic.)

The chief elements of the MR Program are as follows:

l. SSCs are evaluated according to risk significance determination for incorporation into the program using the guidance ofNUMARC 93-01.

2. Risk-informed performance criteria are established to discern whether or not preventative maintenance activities are being effectively implemented for the SSC.

Performance criteria typically consider both SSC reliability and availability. There are additional performance criteria that are also established at the plant level.

3. According to part (a)(3), SSCs are routinely monitored against the established performance criteria, primarily by System/Strategic Engineers working within the Corrective Action 4.2-3

Program (CAP). If the SSC meets all performance criteria, it maintains a normal or **(a)(2) status** under the rule/program. If a problem occurs that results in the performance criteria for an SSC not being met, the problem is reviewed to determine if a Maintenance Preventable Functional Failure (MPFF) has occurred. An MPFF is defined as, **a failure that could have been prevented by the performance of appropriate maintenance.**

4. If an SSC exceeds its performance criteria for unavailability, for the numbers or types of MPFFs, or for a repeat MPFF, then the system is elevated for additional action under section ( a)( 1) of the rule/program, also referred to as being in.. ( a)(l) status:*

5. SSCs placed in (a)(l) status are further reviewed for additional corrective actions to improve maintenance, and goals are established to monitor the effectiveness of the additional maintenance actions. Once the additional actions are complete and monitoring goals are met, the system may be returned to (a)(2) status.

In addition to the role that System/Strategic Engineers play in implementing the MR Program, DCPP has a Maintenance Rule Expert Panel made up of representatives from Operations, Engineering, Maintenance, and the Probabilistic Risk Assessment Group. The Expert Panel reviews any changes to the program, changes to performance criteria, and transfers of SSCs between (a)(2) and (a)(l) status, and the Panel also ensures that a periodic assessment of the program is performed at least every two years.

DCPP appeared to have implemented its Maintenance Rule Program effectively. Twelve of thirteen systems in (a)(l) status have completed maintenance corrective actions and were in the monitoring phase with estimated return to (a)(2) (effective preventive maintenance) status in 2022. One system was undergoing maintenance corrective actions.

Online Maintenance Scheduling (Volume II, Exhibit D.9, Section 3.12)

Corrective Maintenance activities are initiated through the reporting of equipment deficiencies into the Corrective Action System as Notifications. Notifications are reviewed for significance by the Shift Supervisor every shift and further reviewed daily by the Daily Review Team (DRT; also called Notification Review Team). (Daily Review Team meetings are regularly observed by the DCISC.) The ORT classifies and prioritizes Corrective Maintenance activities based upon the importance of the system or component and the significance of the deficiency. The DRT process is governed by procedure AD7.1D2, :-Daily Review Team," Revision 39, a copy of which was provided to the FFT. Urgent deficiencies are assigned to the Fix-it-Now (FIN) Team for repairs, and all other deficiencies are entered into the routine work management process. Also, the highest priority deficiencies are entered into a priority work list on the station Plan of the Day to ensure close monitoring and tracking through resolution.

Corrective Maintenance activities that are not assigned to the FIN Team are entered into DCPP"s 12-week rolling matrix for maintenance activities. The 12-week rolling matrix, developed in advance to cover DCPP"s pre-planned online maintenance for all the major Systems, Structures, and Components, was based primarily upon the Surveillance Tests that were required to be 4.2-4 I

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I performed during Technical Specifications MODE 1, Power Operation.

By knowing which equipment is planned to be taken out of service 12 weeks ahead of time, DCPP can manage the scheduling of online maintenance to minimize any increases in risk due to maintenance activities.

This process is governed by procedure AC7.DC6, *'Online Maintenance Risk Management,"

Revision 28, a copy of which was also provided to the FFT. This process for managing online maintenance also ensures compliance with the NRC Maintenance Rule, 10 CFR 50.65, Section (a)(3), which requires facilities to ensure that the amount oftime that equipment is unavailable due to maintenance is balanced against the reliability improvements achieved by performing maintenance. The 12-week matrix process ensures this is the case by bundling all maintenance activities for a particular component into the same window of unavailability, and thereby minimizing the amount of equipment unavailability required to perform online maintenance activities.

Proposed maintenance activities are reviewed by the Integrated Risk Review Team (IRRT). The IRRT is composed of representatives from Operations (a Senior Reactor Operator),

Instrumentation and Controls Maintenance, Mechanical Maintenance, Electrical Maintenance, Radiation Protection, Chemistry and Environmental Services, Safety, Security, Engineering Services, Emergency Planning, and Work Planning. Normally, DCPP"s Work Week Manager or Outage Manager serves as chairperson for the IRRT meeting. Procedure AD7.1D14, **Assessment of Integrated Risk," Revision 30, governs the work of the IRRT and specifies the various ways in which the IRRT should assess the overall risk of the proposed work activities to ensure the safety of the plant and personnel.

DCPP uses the Phoenix Risk Model provides a quantitative analysis of risk (i.e., changes in reactor Core Damage Frequency) presented by taking specific equipment out of service as well as that resulting from removing a number of different pieces of equipment from service at the same time.

The computer program displays the aggregate risk presented by the postulated work plan in a color context of Green, Yell ow, Orange, or Red, with Red being the greatest risk. The FFT was satisfied that DCPP had satisfactory procedures and programs in place for managing online maintenance activities.

DCPP had satisfactory procedures and programs in place for managing the risks of performing maintenance activities online.

Maintenance Department (Volume II, Exhibit D. 9, Section 3.13)

The DCPP Maintenance Department had undergone a significant reorganization prior to the DCISC visit. The reorganization was initiated in response to several supervisory losses but also was used to position the department for future reductions in planned maintenance activities that would occur as the plant approached the cessation of power operations. In the past, each shop in the Maintenance Department contained a manager, for a total.of six managers. Recently, the number of managers was reduced to three as several maintenance shops were reorganized to be led by two General Foremen positions in each shop. The Maintenance General Manager now oversaw three shops (Instrumentation and Controls, Mechanical and Electrical) each of which was led by two General Foreman. The Maintenance Support Manager oversaw the Fix-it-Now Team 4.2-5

as well as the Maintenance Construction group. The Work Control group continued to be led by an individual Manager. Current department staffing was at about 260 PG&E employees with about 50 contractors.

It was anticipated that staffing would be reduced in the coming months as individuals retired, chose to take jobs elsewhere, or participated in PG&E"s Voluntary Separation Program.

DCPP noted that staffing in Electrical Maintenance was becoming particularly susceptible to future losses as there were numerous other positions available within PG&E in the local area for electricians.

Maintenance Department* performance had improved and was now very good.

This was demonstrated mostly by successful execution of maintenance activities during the recently completed Refueling Outage 1 R23. There were no major issues or human performance problems for the department during the outage. The improved performance had been recognized by the Quality Verification Department and the Institute for Nuclear Power Operations, both of which recently moved their performance indicators for the department from Yellow to Green.

DCPP believed that the Observation Review Meetings (ORMs) had become more effective in raising and discussing performance problems. The ORMs were now conducted weekly within each shop, and the methodology was changed to align with similar efforts that had been successfully implemented within the Operations Department. The meetings focused on obtaining frequent observations of work in the field which were rolled up and discussed in the ORMs. The discussions focused on identifying individual worker activities that did not meet station standards and providing effective feedback regarding needed improvements. The ORMs strove to ensure that observations and corrective actions were being driven down to the level of providing effective feedback to individual workers.

Maintenance Department performance at DCPP continued to be good. The DCISC should review Maintenance Department performance again in about one year given recent organizational changes and staffing reductions.

Also, the DCISC should review the Voluntary Separation Program that was recently initiated by PG&E and which could have a significant effect upon staffing at DCPP.

Foreign Material Exclusion Program (Volume II, Exhibit D.9, Section 3.14)

DCPP's FME Program is governed by procedure AD4.ID6, '*Foreign Material Exclusion Program," Revision 27, a copy of which was provided to and reviewed by the Fact-finding Team.

The purpose of the FME Program is to prevent the undesired and potentially harmful intrusion of foreign materials into plant systems or components. Situations in which this intrusion can most likely occur are during maintenance when normally closed systems and environments are open or during inspections or tests under similar conditions. In such situations, it is important to maintain control of tools, fasteners, repair parts, replaced parts, safety items, residue resulting from the work, items attached to clothing, and anything else that could become loose and enter a system or environment. The vast majority of FME problems typically occur during plant outages when many system repairs, modifications, inspections, and tests are performed.

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I FME program results for Refueling Outage 1 R23 was generally considered as very good performance. The following is a summary and classification of FME issues that were recorded during the outage:

Zero Significant FME Events (highest level issues)

One FME Threat (moderate issues)

Six FME Conditions (low-level issues) 12 FME-related Notifications generated Notably there were no FME issues involving the Reactor Cavity in Containment or involving work on the replacement of a High Pressure Turbine Stop Valve. The one FME Threat that occurred involved a tool that broke inside of an electrical cabinet during maintenance on the Eagle 21 Plant Protection System. Parts from the broken tool fell into portions of the cabinet that were difficult to access and retrieve. An extensive three-day effort was made to inspect all areas of the cabinet and retrieve all of the parts. The effort was successful in retrieving all parts except one small piece of metal that was reviewed by engineers who concluded that the missing piece would not impact operations. DCPP provided the FFT with an Emerging Issue tracking document providing further details on the problem and subsequent corrective actions. Additionally, DCPP reported that a Notification (SAPN 51149742) was written on the identification of a trend regarding FME and tooling issues during the outage, and he provided a copy of the Notification to the FFT. The FFT concluded that the one FME Threat that occurred was appropriately handled, and overall FME performance was very good during the outage.

DCPP's performance in Foreign Material Exclusion during Refueling Outage 1R23 was very good.

4.2.3 Conclusions and Recommendations

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Conclusions:==

DCPP Maintenance performance has improved and functions with high performance indicators.

Recommendations: None 4.2-7

4.3 Engineering Programs 4.3.1 Overview and Previous Activities The following are engineering-related items the DCISC reviewed in the previous reporting period:

1. Buried Piping and Tanks Program

2. Postponed/Canceled Projects

3. Seismically Induced Seismic Interaction Program

4. Engineering Reorganization and Excellence Plan

5. Vibration Monitoring Program

6. Boric Acid Corrosion Control Program The DCISC concluded the following during the previous reporting period:

The DCPP Engineering organization has undergone an extensive revision in that engineers are focused more specifically on systems, components, programs and support. This appears to be a positive move to more efficiently and specifically concentrate efforts on these aspects of the plant. The DCPP Engineering Excellence Plan has been shown to be effective in bringing "technical conscience" to DCPP, not only in Engineering, but also Operations and other technical groups in the plant.

4.3.2 Current Period Activities During the current period, the DCISC had presentations on engineering programs at six Fact-finding meetings. The following topics were reviewed:

1. Single Point Vulnerabilities

2. Strategic Engineering Department Update

3. Configuration Management Program

4. Flow Accelerated Corrosion Single Point Vulnerabilities (Volume II, Exhibit D.6, Section 3.10)

DCPP first studied this issue in 2002. At that time, a single component would be classified as an SPV component ifits failure (alone) could result in a reactor trip or turbine trip, or a plant decrease in power of greater than 2% power. In 2006, DCPP began a more extensive SPV study on all systems (about 20) that had an impact on either generation or reliability and completed it in 2008.

In the 20 reviewed plant systems, over 1,500 SPVs were identified and evaluated for the two units (over 750 for each individual unit). This was a collaborative effort with support from industry organizations such as the Electric Power Research Institute (EPRI) and the Nuclear Energy Institute (NEI). As a result of these studies, actions were initiated on some SPVs to eliminate them by modifications and/or to minimize or eliminate their failure rate by changes in Preventive Maintenance (PM) practices. By 20 I 5, all these actions had been completed and all SPV s were considered mitigated either through modifications or improved maintenance practices.

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I In response to industry guidance DCPP undertook an effort to reclassify components in its Preventative Maintenance program. Then, it undertook a review of all components previously classified as critical in the plant's database system to determine the needed changes to classification codes. The database served to contain and manage all component classification codes as well as the applicable Preventative Maintenance tasks and schedules.

The resulting recommended classification code changes were further reviewed and approved by the applicable System Engineers and the Plant Health Committee prior to implementation. The review resulted in a reduction in the number of components classified as SPV s from over 1500 to 931.

Many of the items that were removed from the SPV classification were components that were a part of redundant trains which became SPVs only when one of the redundant trains was out of service for mainten;mce. The station believed that this situation was adequately addressed by current programs that were in place to protect a redundant train of equipment when the opposite train was out of service.

The scope of SPV has now been revised to the following:

Reactor trip Turbine trip There are no open SPVs currently at DCPP. DCPP has added a screening question for SPV in their design change procedure, so that the possibility of introducing a new SPV will be considered in any design changes. This is a good practice.

DCPP has no current open Single Point Vulnerabilities (SPVs), which is positive.

Additionally, they have added an SPV screening question to their design change process, which will prevent or account for new SPVs.

Strategic Engineering Department Update (Volume II, Exhibit 0.7, Section 3.6)

There were currently 31 engineers in the department, a staffing level that had remained stable over the last few years. A few Strategic Engineers were close to retirement and could be lost within the next two years; however, DCPP expected that most staff would stay through the cessation of power operations.

Engineering was focused upon implementing five applicable initiatives of the Engineering Department Excellence Plan within the Strategic Engineering Department as follows:

l. Improve Engineering Human Performance and Safety Proficiency - This initiative was being addressed via a focus on knowledge transfer and a focus on performing observations of engineers working in the field during the upcoming outage.

2. Improve Response to Equipment Reliability Concerns - This initiative was being addressed through increased management oversight of maintenance backlogs and through quarterly reviews by the Equipment Reliability Performance Management 4.3-2

Monitoring team. Also, '*What Excellence Looks Like'" (WELL) sheets on Equipment Reliability were being used to guide management observations of engineering work activities.

3. Rigorous/Efficient Engineering Evaluations - An increased focus was being placed on standards for Engineering Evaluation formats and ensuring Engineering Evaluations addressed all applicable issues.

An Engineering Product Review Team met periodically to review Engineering Evaluations against standards, and the results were distributed to all engineers.

4. Utilize Knowledge Transfer and Training to ensure Engineering Knowledge and Proficiency is Maintained -

Each employee was being assigned an Individual Education Plan, and training activities were being focused on the needs identified in the plans.

5. Improve Resource Management'- Management was focusing upon a gradual (~10%)

reduction in engineering staffing as the amount of work decreases with the approach of the cessation of power operations. Managers were also looking for efficiencies to be gained through possible reorganizations and/or possibly moving to staffing based more on discipline areas rather than individual systems.

DCPP plant systems were organized along a three-tier approach to system health monitoring as follows:

Tier 1 - Systems most important to nuclear safety and plant reliability which include Mitigation System Performance Index systems and top industry scram vulnerable systems.

Tier 1 systems have a System Engineer assigned and are monitored using System Health Reports and periodic reviews by the Plant Health Committee (PHC).

Tier 2 - Systems important from a nuclear safety, plant reliability, and risk standpoint but not meeting the Tier 1 criteria. Tier 2 systems have a System Engineer assigned to oversee the long-term plan for the system, but there are not any regular System Health Reports or PHC reviews. Significant issues on Tier 2 systems are tracked for resolution via System Health Action Plans in the Corrective Action Program.

Tier 3 - Systems not meeting either of the criteria of Tier 1 or Tier 2. Tier 3 systems have a Point of Contact in the System Engineering group to assist with issues as needed.

There were three systems with **Red'. (Unhealthy) ratings - both units' Emergency Diesel Generators and the Unit 2 Condensate System. There was one Tier 1 system rated as --Yellow" (Needing Improvement) - the Unit 2 Stator Closed Cooling Water System. He also reported that there were five Tier 2 systems with open System Health Action Plans - Unit 1 Containment Ventilation, Units 1 and 2 non-safety related Radiation Monitoring, and Units 1 and 2 offsite power supplies. All of the Tier 2 Action Plans were scheduled to be completed before the end of 2022.

Also, the DCISC was aware of and had previously reviewed all of the issues driving the Tier 1 Red and Yellow ratings and the Tier 2 Action Plans.

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DCPP's Strategic Engineering group continued to effectively manage the health of systems important to safety, and the overall health of station systems was good. The Depar~ment was working to address performance concerns identified by external organizations.

Configuration Management Program (Volume II, Exhibit D.8, Section 3.9)

Configuration Management (CM) is defined as: --a systematic approach for identifying, documenting, and changing the characteristics of a facility's Structure, System, or Components (SSC) and ensuring that conformance is maintained between the design requirements, physical plant configuration, and facility configuration information. DCPP programs, processes, and procedures assure that CM elements conform at all times, all changes are authorized, and conformance can be verified:'

The effectiveness of a Configuration Management Program (CMP) can be impacted by the number of activities in which a station is engaged that can alter the physical configuration of plant systems or their supporting document. Accordingly, station-wide performance in CM is reported monthly in the station's Plant Performance Improvement Report (PPIR). The one-page listing for CM displays a rating for each of nine specific Performance Indicators (Pis) that are reflective of performance in CM.

The DCPP CMP backlog was zero, which is excellent performance. It is important that design documents and procedures keep up with plant changes to reflect as-built conditions. The CMP workload has been decreasing steadily as changes to the plant have decreased in anticipation of the plant's ceasing power production in 2024 and 2025. Because of this slowdown, DCPP CMP was updating and digitizing PG&E's hydroelectric station documents, especially design drawings.

DCPP performed a Design Basis Assurance Inspection (DBAI) Quick Hit Self-Assessment (QHSA), the objective of which was to review readiness for an NRC inspection to verify that the design bases associated with the structures, systems, and components are adequately maintained and implemented at DCPP. The QHSA team performed a deep dive on the past DCPP NRC DBAI and previous DBAI QHSA to determine if there were any open issues, issues that have yet to be resolved. Lastly the QHSA team analyzed all DA SAPNs (Quality-related Corrective Action Program notifications), open and closed, written against the Engineering Department. From this analysis, the QHSA team attempted to determine if there were any areas where possible DBAI findings could arise. The QHSA concluded the following:

Effective utilization of the Corrective Action Program has ensured that issues impacting Diablo Canyon Power Plant design basis have and will continue to be addressed.

The study of industry violations, and DBAI inspection violations has provided a clear list of violation attributes. Understanding these attributes is the first step in prevent NRC DBAI violations.

Ambiguities still exist between licensing and design basis documents, for which Corrective Action Program Notification 51144920 was written.

4.3-4

The DCPP Configuration Management Program (CMP) appeared healthy and currently had a zero back.log, which meant that DCPP's drawings and procedures were up to date, reflecting as-built plant conditions. DCPP's Self-Assessment of its CMP for determining readiness for a June 2022 NRC inspection appeared satisfactory.

Flow Accelerated Corrosion (FAC) Program (Volume II, Exhibit D.9, Section 3.5)

F AC refers to a phenomenon wherein the combination of the removal of a magnetite (iron corrosion) layer by fluid flow and the subsequent increased corrosion of the exposed piping metal can lead to rapid wall thinning and leaks or ruptures. Susceptible components include carbon steel and low alloy steel piping, tubing, and vessels exposed to flowing water or wet steam particularly at bends, elbows, tees, and any other location where turbulent flow exists. The objective of the DCPP FAC Program was to provide a high degree of confidence against the rupture of FAC-susceptible piping systems, and most F AC-susceptible piping was contained in non-safety related systems. DCPP's program covered the identification of F AC susceptible systems, predictive modeling, plant and industry operating experience, ultrasonic inspection techniques, component acceptance standards, program performance criteria, piping repair and replacement, and F AC Engineer Qualifications. The F AC Program established inspections of piping wall thicknesses to be performed during each outage. After the inspections were completed, data were entered into a software program that tracks degradation and predicts areas requiring future inspections or possible replacements. In general, DCPP has, over the history of the plant, been proactive at replacing sections of piping susceptible to F AC with alloy materials that are not as susceptible.

These efforts include replacing high pressure #1 and #2 extraction steam piping, final feedwater piping, and portions of the Condensate Polisher system.

As a result of DCPP's proactive replacements, the number of piping replacements required to address inspection deficiencies has typically been low compared to the rest of the nuclear industry.

Additionally, the number of inspections required during each outage has been significantly reduced as the planned cessation of operations approaches.

DCPP continues to manage its Flow Accelerated Corrosion Program effectively.

The numbers of inspections and replacements performed as a part of the Program were now relatively low historically and will continue be low as DCPP approaches the cessation of power operations.

4.3.3 Conclusions and Recommendations

==

Conclusions:==

The DCPP Engineering organization* continues to provide excellent performance in supporting the plant. Staffing is being carefully reduced in planning for cessation of operations in 2025 to not adversely affect the safety of operations.

Recommendations: None 4.3-5 I

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I 4.4 Human Performance: Human Errors and Improving Safety and Efficiency of Plant Performance 4.4.1 Overview and Previous Activities Human Performance is usually used to refer to --human errors'" and the term is used herein in that manner. The issues around plant safety and plant efficiency having to do with human error reduction are also included in this section. The goal of the human performance program is to reduce the number of human errors to improve plant safety and plant efficiency by improving human performance.

During the previous reporting period, the DCISC reviewed the following topics related to Human Performance at one Fact-finding Meeting:

Human Performance Update The DCISC concluded the following during the previous reporting period:

The DCISC found that human performance events at DCPP were being effectively captured and trended with appropriate corrective actions being initiated when needed. The station improved its performance in reducing Station Level Events but recorded an undesirably high number of Department Level Events during Refueling Outage 1R22. The number of Department Level Events was reduced during Refueling Outage 2R22.

4.4.2 Current Period Activities During the current period, the DCISC had presentations on human performance at one Fact-finding Meeting. The following topic was reviewed:

Human Performance Update Human Performance Update (Volume II, Exhibit 0.8, Section 3.11)

DCPP classified all Human Performance (HU) events and records in the Corrective Action Program CAP for action and resolution. The classifications were as follows:

Station Level Events (highest significance)

Department Level Events Organizational Learning Opportunities (lowest significance)

The DCISC reviewed monthly data on HU events since September 2020 and noticed two trends:

First, the highest numbers of HU events occurred during outages, which was to be expected given the high level of work activities during outages. Second, practically all the events were classified as Organizational Learning Opportunities, which meant that very few of the HU events were significant enough to be classified higher as Station Level Events or Department Level Events 4.4-1

(OLE). Having only one SLE since September 2020 indicated that DCPP's HU performance was good.

The DCISC found that human performance events at DCPP were being effectively captured and trended with appropriate corrective actions being initiated. Since September 2020, DCPP had one Human Performance event classified at the highest significance level (Station Level Event) which was good performance.

4.4.3 Conclusions and Recommendations

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Conclusion:==

The DCISC found that human performance events at DCPP were being effectively captured and trended with appropriate corrective actions being initiated. Since September 2020, DCPP had one Human Performance event classified at the highest significance level (Station Level Event) which was good performance.

Recommendations: None 4.4-2 I

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4.5 Nuclear Safety Culture, and Safety Conscious Work Environment 4.5.1 Overview and Previous Activities The purpose of Nuclear Safety Culture, and Safety Conscious Work Environment (SCWE) is twofold: 1) the health of the individual employee, and 2) nuclear and personnel safety as the context and requirement for all DCPP employees. Included in the area are all health-related issues.

This section also focuses on Safety as a contextual, cultural requirement.

In the previous reviewing period the DCISC reviewed the following:

Employee Concerns Program The DCISC concluded the following:

The DCPP Employee Concerns Program, part of it Nuclear Safety Culture, appeared to be functioning effectively in addressing employees' concerns.

4.5.2 Current Period Activities During the current period, the DCISC reviewed *the following topics that focused specifically on Health, Nuclear Safety Culture, or Safety Conscious Work Environment:

Safety Culture and Safety Conscious Work Environment (SCWE)

DCPP Safety Culture and Safety Conscious Work Environment (Volume II, Exhibit 0.2, Section 3.3)

A key element of safe nuclear power plant operations is safety culture, and the traits of a healthy nuclear safety culture include establishing and maintaining an environment where employees will raise concerns at a low level and the plant management team will respond and correct issues. A healthy nuclear safety culture requires a collective commitment from leaders and individuals to emphasize safety over competing goals to ensure the protection of people and the environment.

Key elements of a healthy nuclear safety culture include an individual commitment to safety, personal accountability, a questioning attitude, and effective safety communication, as well as management's commitment to safety leadership, safety values and actions, decision-making, and a respectful work environment.

The Employee Concerns Program (ECP) provides an alternate venue outside the management chain for employees to raise concerns, to seek intervention and consultation, or to request an independent investigation for resolution of nuclear safety and quality concerns. The ECP is comprised of three independent, qualified team members who report directly to the Chief Nuclear Officer.

4.5-1

The DCPP Nuclear Safety Culture Monitoring Panel (NSCMP) assesses nuclear safety culture using the recommendations of NEI publication 09-07, "*Fostering a Healthy Nuclear Safety Culture," which places primary responsibility on management to provide an ongoing holistic, objective, transparent and safety-focused process. The process evaluates inputs from the Corrective Action Program, performance trends, NRC inspections, industry evaluations, audits, and operating experience, independent and self-assessments, and the Employee Concerns Program. The NSCMP monitors these inputs to identify early indications of potential concern in the work environment that merit additional attention by the organization. Members of the labor unions serve on the NSCMP, and they see benefit in having a healthy nuclear safety culture and management and union efforts in support have proven to be a mutually beneficial partnership. The NSCMP second quarter 2021 report to management concluded "*The Panel believes that safety culture is acceptable.** There were three areas of concern as follows:

1. Attrition in Engineering resulting in a possible lack of proficiency was a concern by some.

This was being addressed by Engineering management.

2. There has been a rise in the number of personnel conservatively self-reporting conditions that could impact fitness for duty. This was considered positive, and there were no actual impacts to fitness for duty.

3. Some employees reported non-adherence to parking standards and unsafe driving practices. This was sent to the Parking Committee for consideration.

Regarding the need to maintain a healthy nuclear safety culture during the period when the plant is proceeding to closure, DCPP recognizes its programs, including programs fostering nuclear safety culture, exist in an environment of both climate and culture and that has changed given the decision to retire DCPP in 2025. The formation of the People Committee was a response to this change in order to monitor and assess plans for continuing employee engagement, staffing, succession planning and other issues: DCPP recognizes the need to assess how its employees continue to feel about raising issues or engaging with management and conducts anonymous surveys, called Pulse Surveys, reaching out to approximately 400 plant staff on a quarterly basis.

The results of the Pulse Surveys are reviewed by the People Committee.

The NRC periodically conducts its Problem Identification and Resolution Inspection which is a team inspection devoting a significant number of resources to investigation of the plant's safety culture and Corrective Action Program use and effectiveness. DCPP management has the benefit of the feedback from and results of the NRC assessment. INPO also places primary importance on and assesses safety culture during its reviews and conducts interviews and holds discussions with plant personnel at various levels.

4.5.3 Conclusions and Recommendations

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Conclusions:==

DCPP Nuclear Safety Culture and Safety Conscious Work Environment appear to be healthy and positive. Employees appear open to reporting concerns in any area of employment. None of the concerns involved nuclear safety.

Recommendations: None 4.5-2 I

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I 4.6 Performance Improvement Programs 4.6.1 Overview and Previous Activities Performance Improvement Programs included multiple programs that were a part of DCPP's Performance Improvement Initiatives, such as Corrective Action, Industry Operating Experience, Benchmarking, Self-Assessments, etc. Many consider these to be **learning** programs whereby the organization learns to improve from its and others* experiences. As have all nuclear plants, DCPP has implemented a Corrective Action Program (CAP). The CAP is a formal, controlled process used to identify and correct problems which occur. A key part of the CAP is root cause analyses, which are utilized to ascertain the real causes of problems or events such that corrective actions can be taken to prevent their recurrence.

During the previous reporting period, the DCISC reviewed the following topic related to Performance Improvement Programs at three Fact-finding Meetings and one Public Meeting:

Corrective Action Review Board Meetings Self-Assessment Program Performance Improvement Programs The DCISC concluded the following during the previous reporting period:

The DCPP Corrective Action Review Board meetings on August 19, 2020, November 10, 2020, and April 28, 2021, were conducted satisfactorily and discussions of significant items were comprehensive. DCPP's Self-Assessment Program continues to be an active and effective program for evaluating and improving station performance.

Following the identification that several recurring Self-Assessments had not been completed within the periodicity required by station procedures, appropriate corrective actions were initiated.

4.6.2 Current Period Activities During the current period, the DCISC reviewed Performance Improvement Programs at three Fact-finding Meetings. The following topics were reviewed:

Operating Experience Program Update Notification Review Team Meeting Benchmarking Program Corrective Action Review Board Meeting Operating Experience Program Update (Volume II, Exhibit D.4, Section 3.6)

DCPP"s Operating Experience (OE) Program was governed by procedure OM4.ID3, '*Operating Experience Program;* a copy of which was provided to and reviewed by the DCISC. Industry OE information came to DCPP from two primary paths: 1) IRIS (formerly ICES, Industry Consolidated Event System), and 2) other sources, including NRC, industry vendors, international 4.6-1

data bases, peer committees, engineering news, etc. From these sources the plant received 15 to 20 OE Reports per week. These OE Reports were entered into an OE Database for tracking, and the information considered to be relevant to DCPP was transmitted to DCPP department Subject Matter Experts who reviewed the material for specific applicability to their areas and determine if action is required. Reviews were formally documented and retained in the OE Database.

If the OE event was determined to be applicable to DCPP, the SME created a Corrective Action Program Notification (SAPN) in DCPP's SAP information management system to initiate and track further actions. Once entered in the SAP system as a Notification, the OE event must be fully reviewed for applicability and any corrective actions for DCPP must be developed and assigned within 60 days. The 60-day standard was closely tracked, and no exceptions were allowed.

The DCISC inquired if there had been any problems or issues identified recently with the OE Program either by internal or external organizations. There was one recent case in 2018 involving a missed opportunity in a 2011 OE Program item, Auxiliary Feedwater System piping leaks, which DCPP experienced in June 2020. The event consisted of corrosion and leakage underneath pipe insulation, which had not been regularly inspected. The occurrence of this event at DCPP could probably have been prevented if the 2011 OE Program event had been adequately reviewed and an inspection program initiated.

DCPP's Operating Experience Program was healthy and appeared to be implemented effectively except for a missed opportunity in 2011.

Notification Review Team Meeting (Volume II, Exhibit D.7, Section 3.4)

Notifications were electronic documents used by plant personnel to identify and record plant problems, large or small, for tracking to resolution in the Corrective Action Program. The DCISC was provided a copy of and reviewed the procedure governing the functions of the Notification Review Team (NRT), OM4.ID14, '*Notification Review Team... The NRT was responsible for evaluating and classifying each work-only '*DN" and quality-related.. DA" Notification for appropriate disposition.

DNs were assigned for all equipment/system problems for which corrective actions were necessary and for all other requested work not associated with problem resolution. Additionally, a DA notification denoted an issue as a condition adverse to quality, also called a '"Condition Report."

DA Notifications were reviewed by the NRT, classified by significance level, and assigned to the organization responsible for resolution by the NRT within five working days following supervisor approval and operations review.

The DCISC observed the March 23, 2022, NRT meeting which was facilitated by a Senior Performance Improvement Coordinator. the NRT reviewed 54 Notifications from the previous day during the meeting. Each team member had reviewed all Notifications prior to the meeting and electronically shared any comments or questions with the other NRT members. The DCISC observed that the NRT members were well prepared for the meeting and knowledgeable about the notifications reviewed. Eight of the fifty-four Notifications were reviewed in more detail during the meeting to address comments or questions raised by NRT members prior to the meeting.

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I The March 23, 2022, meeting of the DCPP Notification Review Team was conducted efficiently and effectively.

The team appropriately reviewed and dispositioned approximately 60 Notifications from the previous day.

Benchmarking Program (Volume II, Exhibit 0.7, Section 3.9)

The DCISC was provided and reviewed a copy of Station Procedure OM 15.104, **Self-Assessment and Benchmarking," Revision 16. The procedure defined Benchmarking as, --A study to identify industry best practices in an external organization.... Benchmarking activities at DCPP were mostly informal. They could be initiated via many paths, but most were initiated as a result of questions raised during procedure revisions, action items from the Corrective Action Program, questions or tasks arising from management meetings, and visits/interactions with other organizations ( conferences, other nuclear plant visits, etc.). There were no specific goals or requirements for the number of Benchmarking activities expected to be completed during any specific timeframe. For reference, DCPP completed 21 Benchmarking activities in 2021, and had completed 16 in 2022 as of the date of the DCISC's reviews. The number of Benchmarking activities completed in the past two years was lower because of a reduced amount of interaction with other organizations due to the limitations of the COVID-19 pandemic.

The DCISC reviewed ten Benchmarking Reports and found that they generally were very good in documenting observations and information gained through the Benchmarking activities. A few included specific action items that were entered into the Corrective Action System for further action and resolution. One (SAPN 51141370, Operations Safety Summit) appeared to be an exception in that it only recorded attendance at a meeting and contained no details about the resulting observations or information gathered.

DCPP's Benchmarking Program continued to be effectively managed and contributed to the improvement of station performance.

• Corrective Action Review Board Meeting (Volume II, Exhibit 0.7, Section 3.9)

The DCISC observed the April 13, 2022, CARB meeting which was conducted remotely and chaired by the Station Director. The Corrective Action Review Board's (CARB's) purpose was to provide a venue for station personnel to demonstrate commitment to Corrective Action Program (CAP) excellence. The CARB fulfilled a need for senior management oversight of the CAP, and this oversight function included:

Reviewing Root Cause Evaluations (RCEs) for accuracy, completeness and alignment of the problem, causes and corrective actions Approving extensions to the due dates for Corrective Actions to prevent recurrence.

Approving Effectiveness Evaluations for CAP documents Periodically reviewing CAP metrics to ensure the CAP is meeting management expectations Reviewing and dispositioning requests for Cause Evaluation downgrades Reviewing notifications screened by the Notification Review Team 4.6-3

The April 13, 2022, DCPP Corrective Action Review Board (CARB) meeting moved along expeditiously, although thoroughly, effectively resolving the issues and actions on its agenda.

There was good participation by all CARB attendees.*

4.6.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's Operating Experience Program was healthy and appeared to be implemented effectively except for a missed opportunity in 2011. A March 23, 2022, meeting of the DCPP Notification Review Team and an April 13, 2022, meeting of the Corrective Action Review Board (CARB) were both conducted efficiently and effectively. DCPP's Benchmarking Program continued to be effectively managed and contributed to the improvement of station performance.

Recommendations: None 4.6-4 I

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4. 7 Emergency Preparedness

4. 7.1 Overview and Previous Activities An Emergency Preparedness (EP) Program has been in-place since the beginning of the nuclear power industry; however, the accident at Three Mile Island brought substantial changes.

Prior to Three Mile Island, Emergency Operating Procedures (EOPs) were primarily event-based, requiring the operator to know which event was taking place. Afterward, the EOPs became symptom-based, making it easier for the operator to decide what actions to take. The five major EP facilities include ( 1) the Control Room (simulator in practice) where operators respond to the accident, (2) the station Technical Support Center (TSC) where engineering, computer, radiological assessment, NRC, and operations, as well as documents and procedures, are located, (3) the offsite Emergency Operations Facility (EOF) where the Recovery Manager and administrative and technical staff are located, (4) a station Operations Support Center (OSC) that provides a location to stage and dispatch operations, maintenance, firefighting, and radiation protection personnel, and (5) the Joint Information Center (JIC) where DCPP and San Luis Obispo County interface with the media.

The DCISC reviews Emergency Preparedness at DCPP on a regular basis. Past Committee activities have included observations and reviews of drills and full, graded emergency exercises each year and related issues from the observations. The DCISC reviewed the following aspects of DCPP Emergency Preparedness during the previous reporting period:

Use of Social Media in Emergency Preparedness NRC Inspection of Siren Maintenance Emergency Preparedness Virtual Capabilities Emergency Preparedness Update and COVID Emergency Preparedness During Decommissioning The DCPP Emergency Preparedness Program and Emergency Response Organization appeared to be effective and ready to respond to any plant emergencies, including given restrictions caused by the COVID-19 pandemic.

4.7.2 Current Period Activities The DCISC reviewed the following aspects of DCPP Emergency Preparedness during the current reporting period:

Emergency Preparedness Update Emergency Preparedness Exercise Observation Emergency Preparedness Update Volume II, Exhibit 0.1, Section 3.2 and Exhibit D. 7, Section 3.5)

The Emergency Response Organization (ERO) is the group of employees which provides staff for emergency response facilities in the case of an emergency event.

Although Emergency 4.7-1

Preparedness overall is managed by a small group of full-time specialist staff members, the bulk of the ERO is comprised of DCPP employees who are trained and serve in assigned roles as a collateral duty to their regular duties. The ERO is dived into four assigned teams, Alpha, Bravo, Charlie and Delta, with approximately 70 individuals per team who serve "on call" for two weeks out of every eight weeks. Maintaining the proficiency of the ERO teams is an ongoing activity and is given high visibility at the station, including having qualification and training metrics included in the monthly Plant Performance Indicator Report.

The ERO teams had experienced higher than normal turnover in 2020 and 2021 due to retirements, career opportunities from outside of the nuclear industry, and routine internal job changes.

Overall, personnel transitions impacted about 100 team positions ( out of approximately 280 total) during the 18-month period. To maintain a "well-staffed and qualified ERO throughout the transitions, the department had prepared and was implementing an ERO Proficiency Improvement Plan. The goal of the plan was to achieve and sustain ERO performance at industry top quartile level and em,ure a successful completion of the September 2021 emergency exercise. The plan included activities using group leaders to track individual position staffing and requirements and to identify additional future team members to be fully trained and qualified. The goal was to have one or two fully qualified reserve team members for each position in the ERO. Additionally, proficiency of the ERO team members would be enhanced through the use of structured mentoring and the performance of facility walk-throughs using detailed guides on the performance of ERO tasks. Lastly, dynamic learning activities were continuing to be conducted during ERO Muster Meetings, which were held at the start of each team's two-week on-call period. The FFT concluded that the plan appeared appropriate, and the DCISC should verify its effectiveness by observing the upcoming emergency exercise.

During 2021 when COVID-19 precautions were in place, DCPP continued to train and evaluate its four teams of the Emergency Response Organization (ERO). Most of the 2021 training and exercises were done remotely, and Team A of the ERO was provided several opportunities for in-person training in preparation for the evaluated EP exercise. Generally, COVID-19 precautions and turnover among team members led to a few gaps in overall ERO performance that were successfully resolved through implementation of an ERO Trajectory Action Plan, a copy of which was provided and reviewed by the DCISC. In the first part of 2022, transitions back to in-person and in-facility training had also been delayed by new COVID-19 precautions ( due to the omicron variant). Despite the limitations, continuing focus was placed on getting key team members individually into the emergency response facilitates for training on critical ERO functions and tasks. Plans were in place to return to full team training in the emergency response facilities following completion of the upcoming Refueling Outage 1R23.

The DCISC received and reviewed a copy of the current EP Excellence Plan which showed initiatives in the areas of programmatic improvements, ERO leadership, and EP Staff development.

One initiative involved the planned implementation of the Integrated Public Alert and Warning System (IPA WS), which is a nationwide system that uses mobile phone alerts for notifying members of the public about an emergency. Currently, DCPP was in the process of reviewing with off-site partner organizations the possibility of using IPA WS to supplement or replace the use of sirens and/or route alerting. No decision had been made on the future use of IPA WS, but many 4.7-2 I

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I other nuclear power plants nationwide had obtained approvals and were moving toward using IP A WS for emergency notifications.

The EP staff currently consisted of eight employees (seven EP Coordinators and a Manager) which was a reduction down from eleven staff members in past years. Three employees were lost due to retirements, and decisions were made to not fill those positions given the upcoming cessation of power operations. He noted that the Decommissioning Group was also in the process of adding an EP Coordinator to their staff to help coordinate the implementation of post-shutdown Emergency Plan changes.

An audit of the EP Program by the Quality Verification organization resulted in no findings, one deficiency, and two recommendations. The DCISC had been previously provided with a copy of the audit and found that it was generally positive about the performance of the EP Program. The Emergency Services Manager for San Luis Obispo County had recently changed, with Mr. Scotty Jalbert moving up from heading the Fire Department to take the position. The DCISC concluded that DCPP"s EP Department continued to effectively manage EP activities for the station including coordinating effective staffing and training for the Emergency Response Organization.

DCPP appears to be effectively managing staffing and training for its Emergency Response Organization which has been challenged by a high turnover rate among assigned personnel.

Emergency Preparedness Exercise Observation (Volume II, Exhibit 3.3, Section 3.12)

On September 15, 2021, PG&E along with state and local authorities conducted an Emergency Preparedness Exercise which was evaluated by the NRC. The DCISC observed portions of the exercise, beginning with observations at 7:00 a.m. in the Control Room Simulator which served as the Unit 1 Control Room for the exercise for approximately two hours. The consultant then traveled to the Emergency Operations Facility (EOF) and observed activities in the EOF until the conclusion of the exercise about 1 :45 p.m. About one hour of that time was spent in the nearby Joint Information Center (JIC), specifically observing public affairs activities. The basic timeline for the exercise was as follows:

7:00 a.m. - Controller briefings 8:00 a.m. - Exercise begins 8:04 a.m. - Condensate Booster Pump 1-3 failure 8: 18 a.m. - Toxic Gas in Unit 2 Auxiliary Building (Alert declared) 8:40 a.m. - Nuclear Instrument channel 41 failure 9:40 a.m. - Steam Line Break Accident, with reactor trip system failure and Residual Heat Removal Pump 1-2 failure I 0: IO a.m. - Small Break Loss of Coolant Accident (Site Area Emergency declared) 10:30 a.m. - Safety Injection Pump 1-1 failure 11 :00 a.m. - Potential loss of Containment (General Emergency declared) 11 :40 a.m. - Offsite release from Containment 12:00 p.m. - Containment Spray Pump 1-1 failure 1 :45 p.m. - Exercise termination, followed by facility breakout critiques 4.7-3

The DCISC observed that the exercise overall was conducted in an orderly fashion. Controller teams appeared to be well prepared to facilitate the exercise, and controller briefings were thorough and effective. Control Room personnel responded appropriately to simulated conditions, and emergency response personnel staffed emergency response facilities quickly and efficiently. In the EOF, the Emergency Manager was effective at leading PG&E"s response to the event and other supporting teams appeared to work together well. Emergency classifications overall appeared to be proper and timely, although there was some confusion over follow up notifications during turnover from the Control Room to the EOF. Communications were generally clear and effective, except for a few instances of confusing communications from the engineering support team in the EOF. Also, there was confusion over the units and trends for Containment pressure at one point in the scenario. Recommendations for protective actions (notifications and evacuations) appeared to be properly made from PG&E to county and state officials. In the JIC, numerous media releases were made, and they generally communicated details of the situation to the public in a clear and concise manner. Mock press conferences were also held, and PG&E provided audience personnel who effectively simulated media representatives.

Following the exercise, the evaluation by PG&E concluded, **PG&E Emergency Response personnel effectively implemented the DCPP Emergency Plan by demonstrating key knowledge and skills specific to their assigned functions.'*

PG&E's evaluation reported that all emergency classifications, notifications, and protective area recommendations were made accurately and within the prescribed time limits. There was one weakness noted regarding methods used to correlate dose assessment models to dose data collected by field monitoring teams. PG&E"s evaluation was consistent with the DCISC's direct observations during the exercise.

Overall, the DCISC concluded that the Emergency Preparedness Exercise was successfully designed and implemented by PG&E, and it demonstrated that DCPP's staff could effectively implement the facility's Emergency Plan.

4.7.3 Conclusions and Recommendations

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Conclusions:==

The DCPP Emergency Preparedness Program and Emergency Response Organization appeared to be effective and ready to respond to any plant emergencies, including given restrictions caused by the COVID-19 pandemic. The Emergency Preparedness Exercise was successfully designed and implemented by PG&E, and it demonstrated that DCPP's staff could effectively implement the facility's Emergency Plan.

Recommendations: None 4.7-4 I

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I 4.8 Risk Assessment and Management 4.8.1 Overview and Previous Activities PG&E has developed in-house capability to perform risk assessments and periodically updates its Probabilistic Risk Assessment (PRA) to incorporate changes in plant configuration and, if appropriate, operations. PG&E controls its risk from on-line maintenance procedurally. For On-Line Maintenance the PRA Group prepares a Risk Profile on a weekly, monthly and fuel cycle basis. The PRA Group works very closely with personnel performing the On-Line Maintenance risk assessment, and the program has been working well. The On-Line Maintenance (OLM) model has been used by Operations and Maintenance as an on-line planning tool for various operations and maintenance activities.

The DCISC reviewed the following item in DCPP's Probabilistic Risk Assessment Program during the prior reporting period:

Overall DCPP PRA Programs Probabilistic Risk Assessment is an effective tool in understanding and improving nuclear reactor safety. PG&E has established an effective PRA Program staffed by experienced personnel and utilizes PRA to the full extent in analyzing DCPP and in operating DCPP safely.

4.8.2 Current Period Activities The DCISC reviewed the following topics during the current reporting period:

o Probabilistic Risk Assessment Program o

Integrated Risk Management Probabilistic Risk Assessment (PRA) Program (Volume II, Exhibit D.3, Section 3.1)

• Status of the PRA: Although the PRA group keeps the PRA up-to-date continually as the plant configuration changes over time, and keeps the failure database current, it has performed a major upgrade of the PRA

• s models only every few years, typically every three years or so. At the time of this Fact-Finding Meeting, the group would normally be planning to start the next model-upgrade effort soon, an activity which usually takes about a year. However, because the plant will cease power generation in 2025, the group is not currently anticipating any future major PRA model upgrades. [The distinction between keeping a PRA model up-to-date and performing a PRA model upgrade is well defined in the industry; it essentially differentiates using newer data or modeling a slightly different plant configuration ( an update) from using a new or different model (an upgrade).]

4.8-1

Support for post-shutdown activities: Whether the PRA will require major modifications to remain useful and valid for assessing risks and supporting decision-making after the plant ceases electricity generation in 2025, is an issue that needs to be assessed, and will be assessed by the PRA group soon.

Support for plant safety decision-making: The PRA model is used regularly to support a wide variety of different safety decisions. One application mentioned was when an event or off-normal condition occurs, and the plant needs to analyze it and report about it to the NRC through the NRC"s Significance Determination Process (SOP). The SOP requires using the PRA, among other tools, to understand the risk significance of the event or off-normal condition. The PRA group reported that they had supported SOP analyses recently and successfully. A copy of one of the group's SOP analyses, calculation number SDP21-04, "Unit 1 ASW Pump Motor 1-1 Ground Alarm," Revision 0, was recently provided to and reviewed by the DCISC in its monthly documents package.

Another type of application is when a technical specification change or maintenance interval change is being considered. The PRA can be used to analyze how much change in various risk metrics would result, in order to aid decision-makers. One recent example was PRA support for the situation in which an Emergency Diesel Generator (EOG) fuel-oil-transfer pump motor needed replacement, a situation-that would take the associated EOG out of service for a few days. The PRA was used to demonstrate that the overall increase in risk associated with a seven-day replacement window would be acceptably low, taking into account the availability of a portable engine-driven pump if needed during that interval.. A copy of the assessment, calculation number PRA 21-01, '*OFOTP Motor Replacement," Revision 0, was provided to and reviewed by the FFT.

This PRA analysis satisfactorily supported the plant's position in seeking NRC approval for the

• activity. (In the end, the replacement activity only required about 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.)

Another PRA application, which began over a year ago and continued until recently, was supporting the submittal by PG&E of an exigent License Amendment Request related to potential safety issues with an Auxiliary Feedwater System piping inspection and repair activity. The PRA group performed a PRA-based analysis of the change in risk associated with the proposed inspection and repair activities, which involved taking certain safety equipment out-of-service for a defined few-days interval. The PRA analysis showed that the change in risk was small and well below thresholds of concern.

Reorganization of the PRA group: About a year ago, the PRA group was reorganized by splitting its scope in two. One group, under Rasool Baradaran, has continued with the responsibility to support the plant PRA and applications of it. This is the group whose activities were reviewed during this Fact-Finding meeting. The other group, under Nathan Barber, was formed with the responsibility for what is termed '*generation risk management" that has a company-wide scope, including (for example) supporting risk decision-making related to PG&E's hydroelectric dam electric generation facilities or the company's transmission system. This reorganization change has left the plant-PRA group with a smaller staff. Although on its face this could be a problem for DCPP in a '*pinch," the DCISC was assured that PRA experts in the generation-risk-management area would be available to continue to support the plant-PRA activities to alleviates the concern.

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The DCPP Probabilistic Risk Assessment (PRA) group's work today is emphasizing the support of various PRA applications, mostly driven by internal plant needs but also supporting NRC interface activities as needed. All of these needs are being supported effectively by the PRA group. The DCISC Fact-finding Team concludes that the PRA group is doing excellent work.

Integrated Risk Management (Volume II, Exhibit D.7, Section 3.8)

The DCISC reviewed the Quick Hit Self-Assessment (QHSA; SAPN 51073 735) on the topic of evaluating the station*s alignment with Institute for Nuclear Power Operations (INPO) guidance document 15-011, ""Principles for Excellence in Integrated Risk Management.'" The scope of the QHSA was to evaluate the Operational, Project and Enterprise organizations which interact with DCPP to determine if their management of risk was consistent with the INPO guidance document.

Mr. Barber reported that in general, Operational and Project organizations managed risk well using established practices consistent with the INPO guidance; however, the larger PG&E Enterprise organization functioned separately from the Operational organization and its process for managing integrated risk was not as well established. The QHSA identified a number of enhancements and approximately 11 specific recommendations. The recommendations included:

Establish a process for the station to assess operational evolutions for their potential impact on enterprise risk.

Review the process for identifying and managing risk-significant components in the enterprise data management system (SAP).

Evaluate the need to include a representative from the Probabilistic Risk Assessment group into reviews for Emerging Issues at the station.

Evaluate the need for a Risk Management Team member to attend Risk Challenge Boards during maintenance planning.

Improve attention on non-safety related but risk-significant component issues being processed in the Corrective Action System.

The FFT concluded that the QHSA was well performed and identified a number of significant improvements in the way that PG&E manages Integrated Risk Assessment.

==

Conclusions:==

A Quick Hit Self-Assessment in the area of Integrated Risk Management was well performed and identified a number of improvements in the way that PG&E manages Integrated Risk Assessment.

4.8.3 Conclusions and Recommendations

==

Conclusion:==

The DCPP Probabilistic Risk Assessment program contains effective tools in understanding and improving nuclear reactor safety. PG&E has established an effective PRA Program staffed by experienced personnel and utilizes PRA to the full extent in analyzing DCPP and in operating DCPP safely.

Recommendations: None 4.8-3

4.9 Nuclear Safety Oversight and Review 4,9, 1/

!)verview and Previous Activities Note: because of the confidentiality agreement between the Institute of Nuclear Power Operations (INPO) and its member nuclear plants, and a similar policy governing DCPP's internal Nuclear Safety Oversight Committee (NSOC), only limited information can be presented in this public document.

Nuclear Safety Oversight and Review is an important function in the safe operation of nuclear power plants. This oversight represents an independent, higher and/or broader level of review of operations, events, occurrences, etc. than can be obtained from the organizations performing the day-to-day plant, technical and quality functions. The Nuclear Regulatory Commission (NRC) is charged by law to regulate the nuclear industry. In carrying out this responsibility the NRC issues regulations and guides for nuclear safety and performs inspections at facilities to assure regulations are met. NRC's role at DCPP is discussed in Chapter 3.0 NRC Assessments and Issues. NRC regulations require, and DCPP Technical Specifications (TS) provide for, a high level of oversight in the form of the Nuclear Safety Oversight Committee (NSOC).

Additionally, the nuclear industry monitors and enhances operational safety and excellence with the Institute of Nuclear Power Operations (INPO) which performs periodic performance evaluations of each operating nuclear plant; coordinates the collection, review and dissemination of operating event information; issues good practice guidelines; provides specific event, technical and functional reviews; and issues and monitors performance goals for the industry. PG&E is a member of INPO and participates in their programs.

The Diablo Canyon Independent Safety Committee (DCISC) provides an additional level of nuclear safety review and oversight. As stated in Chapter 1.0, DCISC is charged to "... review Diab lo Canyon operations for the purpose of assessing the safety of operations and suggesting any recommendations for safe operations". In carrying out its responsibilities DCISC receives and reviews DCPP operating and technical and NRC documents; performs fact-findings at DCPP and holds several public meetings and public plant tours each year to hear PG&E reports on plant operational safety and receive public input.

The DCISC observed the following oversight meetings/items during the previous reporting period (2017-2018):

INPO Update NSOC Exit Meeting INPO Corporate Evaluation The DCISC made the following conclusion in the previous reporting period:

Regular nuclear oversight of DCPP by nuclear industry organizations has proved positive for DCPP in reporting positive performance results and by providing helpful input for improved performance in achieving excellence.

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I 4.9.2 Current Period Activities The DC/SC has an agreement with DCPP to maintain Institute of Nuclear Power Operations (INPO) and Nuclear Safety Oversight Committee (NSOC) information confidential, thus on(v limited information is presented here.

The DCISC reviewed the following oversight item during the period 2017 - 2018:

NSOC Exit Meeting INPO Update and Mid-Cycle Review Nuclear Safety Oversight Committee Exit Meeting The DC/SC has an agreement with DCPP to maintain NSOC information confidential, and thus on(v limited information is presented here.

The DCISC FFT observed the July 15, 2021, Nuclear Safety Oversight Committee (NSOC) exit meeting.

The NSOC is a committee of six executive-level, external industry peers. The Committee typically visits DCPP three times per year for four days each. The first three days are usually spent in the plant interviewing personnel, observing activities, and reviewing records in the following NSOC Subcommittee areas:

• Operations, Chemistry, Learning Services

• Maintenance, Work Management, Industrial Safety

• Engineering, Risk Assessment, Equipment Reliability, Regulatory Services

• Performance Improvement, Radiation Protection, Emergency Planning, Security

• Outages, Projects, Decommissioning

• Organizational Effectiveness, Safety Culture, Quality Verification For this meeting, most NSOC members visited the plant to perform several days of direct observations, with additional observations conducted by members via remote meetings. The exit meeting was held on NSOC's fourth day of meetings for the purpose of reporting its conclusions to DCPP's Chief Nuclear Officer and leadership team. The NSOC evaluators appeared thorough in their investigations and candid in their reports. They reported on the status of several previously identified issues and concerns, closing some, and also identified a few new issues and concerns.

Overall, the NSOC evaluated DCPP as continuing to be a top performer in the industry. Many of NSOC's conclusions were similar to those of DCPP's Quality Verification Department and the DCISC.

The DCPP Nuclear Safety Oversight Committee appeared to be thorough and comprehensive in their investigations and candid in their reports.

4.9-2

Institute of Nuclear Power Operations (INPO) Update (Because o_f its privacy agreement with DCPP, the DC/SC cannot share the details of the INPO evaluation or subsequent corrective actions.)

Each nuclear power plant in the nuclear industry is evaluated approximately every two years by the World Association of Nuclear Operators (WANO) or the Institute of Nuclear Power Operations (INPO). WANO is generally responsible for international plant reviews, including those in the U.S., whereas INPO concentrates on U.S. plants only. The two organizations are similar in their charters to help nuclear plants achieve and maintain excellence in nuclear operations. The most recent DCPP evaluation was by the World Association of Nuclear Operators (WANO) in June 2019. DCPP received a high rating with five Strengths and three Areas for Improvement (AFls) in Operations, Maintenance, and Personnel Safety. DCPP had entered these AFis in their Corrective Action Program.

Normally, DCPP would have received its next INPO evaluation in mid-2021, but due to COVID-19 and DCPP's previous high rating, the evaluation was postponed until mid-2022. DCPP performed a limited mid-cycle self-evaluation in June 2020, reviewing corrective actions on the three AFis. They had completed their corrective actions in all except Maintenance, in which the plant was addressing cyclical performance in lnstruinentation and Controls.

DCPP has taken a strong, proactive approach in addressing the results of its June 2019 evaluation by the World Association of Nuclear Operators. All but one of the three Areas for Improvement had been resolved, and the third was being addressed. The next evaluation by the Institute of Nuclear Power Operations will be in mid-2022.

Leadership Engagement and Oversight that Benefits Operational Safety (Volume II, Exhibit B.6)

Both the nuclear industry and the DCPP oversight functions include an overarching belief in continuous improvement as the basis for achieving and sustaining exemplary performance and the values that support continuous improvement include learning, leadership, and talent development.

The process by which plant leadership engages with behaviors that align with those values as include oversight and coaching, monitoring of performance and intervening as necessary to drive performance improvement, the use of self-assessments and benchmarking, 1 together with the involvement of the Corrective Action Review Board, the Plant Health Committee and other higher-level performance review and observation, operating, and management review activities which carry out differing functions.

DCPP operating review meetings focus upon development of a Lean Operating System which was 1 Benchmarking is the practice of comparing business processes and performance metrics to industry bests and best practices from other companies.

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I described as a new concept to both DCPP and PG&E which is focused on safety, delivery, quality, cost, and morale. Operating review meetings are held daily to engage personnel as necessary and the results of those reviews can escalate to the level of the Chief Nuclear Officer.

The performance improvement model used at DCPP employs benchmarking, self-assessment and leadership observations to document problems and departures from exemplary performance in the Corrective Action Program and thereby identify drivers and actions to be implemented to solve problems. The performance improvement model is cyclical and ongoing.

During 2021, DCPP conducted 39 formal self-assessments and 21 formal benchmarking activities.

The Institute of Nuclear Power Operations, (INPO) drives the performance of nuclear power plants across the United States, and DCPP is assessed and assesses itself against INPO's standards. In addition to formal self-assessments and benchmarking activities, informal assessments and benchmarking occurs with regularity and include interaction with the Strategic Teaming and Resource Sharing (STARS) joint utility cooperative organization of which DCPP is a member.

Performance monitoring review meetings and oversight/observation review meetings serve differing functions and occur at different frequencies and include participation from leadership across the station from vice presidents and senior directors to supervisors. Observations are documented and compared against standards to provide cognitive trending in order take appropriate action to drive performance. Cross-functional observation review meetings occur every two weeks and include personnel through the director level. Management review meetings focus not only on observations but also on metrics and key performance indicators. Performance Review meetings are chaired by the Station Director and held quarterly to review departmental excellence plans or performance improvement plans and key performance indicators and often include participation by managers, supervisors and individual contributors. The Plant Health Committee meets weekly to review plant health indicators and the top ten equipment issues and challenges as well as to identify challenges to operators in the field and operator work-arounds.

The Station Oversight Committee established in 2021 in response to a 2020 corporate evaluation includes the Chief Nuclear Officer and the Site Vice President and meets every month when there a Performance Review meeting is not scheduled to conduct a --deep dive review of overall performance and equipment reliability issues and to review safety performance, internal and external audit findings, and corporate station initiatives as well as departmental excellence plans.

The changes in senior leadership were all addressed by DCPP's succession planning process which the DCISC has reviewed. Succession planning includes formal tracking and appraisal of the development of individual contributor's performance and includes establishing goals and assigning job shadowing activities and the delegation to individuals of increasingly responsible assignments to allow prospective successors to build knowledge and proficiency and to gain experience. Job familiarization guides have been prepared for senior leadership for the Chief Nuclear Officer and Site Vice President and other senior leadership positions as well as for managers and supervisors. The Senior Vice President and Chief Nuclear Officer is meeting regularly with corporate mentors and continues to build proficiency in her role.

PG&E"s Board of Directors has a Safety and Nuclear Oversight Subcommittee which meets six or eight times each year and is chaired by PG&E Director Ms. Cheryl Campbell and on which 4.9-4

Director Admiral Mark E. Ferguson III, who retired from the U.S. Navy with nuclear-related operations experience as a four-star admiral, serves as a member. The Board is also engaged in a nuclear performance review session during which the DCPP Chief Nuclear Officer and the Site Vice President will present information concerning nuclear performance to PG&E's Chief Executive Officer and Executive Vice President and Chief Operating Officer prior to a meeting of the Safety and Nuclear Oversight Subcommittee. The PG&E Board of Directors has visited DCPP several times and a full Board visit is scheduled for later in 2022.

4.9.3 Conclusions and Recommendations

==

Conclusions:==

Regular nuclear oversight of DCPP by nuclear industry organizations has proved positive for DCPP in reporting positive performance results and by providing helpful input for improved performance in achieving excellence.

Recommendations: None 4.9-5 I

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I 4.10 Radiation Protection 4.10.1 Overview and Previous Activities DCPP Technical Specifications contain requirements on Radiation Protection, and DCPP has corresponding programs and procedures to specify the details of their radiation protection programs. Although numerical limits are specified, plant personnel are also required to use the

• philosophy of As Low As Reasonably Achievable (ALARA) to minimize radiation exposures and releases. DCPP has a formal ALARA program; the program applies to personnel exposure in the plant as well as releases to the environment.

PG&E files reports semi-annually regarding personnel exposures; releases outside DCPP; and regular soil, vegetation, water and air samples taken around the plant.

During the previous period, the DCISC reviewed Radiation Protection Programs at one Fact-Finding Meeting and one Public Meeting. The following topic was reviewed:

Annual Radiological Release Report and Annual Radiological Environmental Monitoring Report The DCISC concluded the following during the previous reporting period:

The DCPP Radioactive Effluent Release Program and the Radiological Environmental Monitoring Program appeared satisfactory in calculating, monitoring and measuring radioactivity in the environment surrounding DCPP. There were no abnormal releases of radioactivity or abnormal levels of radioactivity detected.

4.10.2 Current Period Activities During the current period, the DCISC reviewed the following Radiation Protection items during four Fact-finding Meetings:

Annual Radioactive Effluent Release Report and Radiological Environmental Operating Report Radi;ition Protection Department Performance Meteorological Information and Dose Assessment System Annual Radioactive Effluent Release Report and Radiological Environmental Operating Report (Volume II, Exhibit D.l, Section 3.4)

DCPP submitted its 2020 Annual Radioactive Effluent Release Report (ARERR) to the NRC on April 20, 2021. This report described the measured/calculated quantities of radioactive gaseous effluents, liquid effluents, and direct radiation released from the plant in 2020. The report included the dose due to release of radioactive liquid and gaseous effluents and summarized solid radwaste shipments. In all cases, the doses associated with plant effluent releases during the report period were much less than the respective Technical Specification, Offsite Dose Calculation Manual 4.10-1

(ODCM), and NRC limits. Overall, the gaseous radioactivity releases from DCPP were well-controlled and maintained as low as reasonably achievable.

There were no abnormal or uncontrolled releases during 2020.

Based on records of 2020 radioactive liquid and gaseous releases, the following off-site radiation doses to the total body of a hypothetical individual at the closest point on the northwest site boundary full-time and the corresponding percent of ODCM limits for the year 2020 were reported in the ARERR:

Effluent Type Liquid Gaseous Calculated Radiation Dose 0.000336 millirem 0.00219 millirem Percent ofODCM Limit 0.011%

0.021%

The 2020 Annual Radiological Environmental Operating Report (AREOR) was submitted to NRC on April 1, 2021. This report described the results of the Radiological Environmental Monitoring Program (REMP), which measures and assesses the levels of radiation or radioactivity in the environment related to operation of DCPP and verifies that DCPP operated within its design parameters. Approximately 278 environmental samples, 884 air samples, and 1440 Thermo-Luminescent Dosimeter (TLD) radiation detectors were collected over the course of the 2020 REMP monitoring period. Approximately 1827 radionuclide analyses were performed on environmental samples.

The annual offsite radiological dose received by the general public from plant operations was less than one millirem which is insignificant when compared to the 620 millirem average annual radiation exposure to people in the United States from natural and man-made background radiation sources (cosmic, terrestrial, radon, medical, etc.).

The ambient direct radiation levels in the DCPP offsite environs did not change and were within the pre-operational background range. An evaluation of direct radiation measurements indicated all U.S. Environmental Protection Agency criteria were met by a large margin. The ambient onsite direct radiation levels within the DCPP plant site boundary near the Independent Spent Fuel Storage Installation (ISFSI) were elevated due to dry cask spent fuel storage. The remaining onsite REMP environmental TLD locations were not affected by the ISFSI due to ISFSI topographical elevation and placement within an onsite hillside which provided shielding to the rest of the site.

An evaluation of direct radiation measurements and member-of-public occupancy times within the site boundary indicated that all Federal criteria for member-of-public dose limits were met by a large margin.

Groundwater isotopic monitoring was conducted in accordance with the Nuclear Energy Institute guidance document NEI 07-07, Revision 1, '*Groundwater Protection Initiative." Concentrations of tritium were detected in two shallow monitoring wells (stations DY I and OWl) near the power block. The levels of tritium detected in groundwater were approximately 2% of federal standards for the allowable maximum concentrations of tritium in drinking water. This tritium was evaluated and attributed to rain-washout of gaseous tritium exiting the plant vent system via an approved and monitored isotopic-effluents discharge path. No groundwater tritium was attributed to DCPP system leaks or spills. It was also noted that studies of the DCPP site groundwater gradient 4.10-2 I

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I indicated that any subsurface groundwater flow beneath the DCPP power block was not used as a source of drinking water. Due to topography and site characteristics, this groundwater gradient flows naturally into the Pacific Ocean which is approximately 100 yards from the power blo_ck.

An Old Steam Generator Storage Facility (OSGSF) long term storage vault was constructed within the DCPP site boundary in 2007 for storage of eight retired DCPP steam generators and two retired DCPP reactor heads. This OSGSF did not cause any changes to the ambient direct radiation levels within the DCPP environs during 2020. The OSGSF in-building sumps were inspected quarterly by REMP personnel and only small amounts of water were found and collected for processing.

via the site's liquid radwaste system.

Overall, the results of the 2020 REMP showed no unusual environmental isotopic findings from DCPP site operations. These results were compared to DCPP preoperational isotopic data and showed no unusual trends. The REMP reported that operation of DCPP continued to have no detectable offsite radiological impact.

Samples analyzed from the offsite sampling stations continued to show no radiological contribution from plant operations.

Diablo Canyon site operations had no significant impact on the health and safety of the public or the environment.

The DCPP Radioactive Effluent Release Program and the Radiological Environmental Monitoring Program appeared satisfactory in calculating, monitoring and measuring radioactivity in the environment surrounding DCPP. During 2020, there were no abnormal releases of radioactivity or abnormal levels of radioactivity detected. DCPP site operations had no significant radiological impact on the health and safety of the public or the environment, and radioactive releases were far below regulatory limits.

Radiation Protection Department Performance (Volume II, Exhibit 0.1, Section 3.13; Exhibit 0.8, Section 3.6; and Exhibit 0.9, Section 3.7)

The DCISC reviewed Radiation Protection (RP) Department performance during Refueling Outage 2R22. Performance was primarily measured by outage Collective Radiation Exposure (CRE) which represents the sum of doses received by all individuals working on site during the outage period. For Refueling Outage 2R22, CRE performance was exceptional, posting the lowest CRE for a refueling outage in the industry to date. The station originally set a CRE goal of 19 person-rem, reduced that goal to 15.3 person-rem early in the outage, and achieved an actual CRE of 10. 7 person-rem. The low CRE was attributed to ongoing activities to reduce the Reactor Coolant System source term, real-time monitoring and tracking of worker exposures, and shielding enhancements. Additionally, a delay in the start of the outage due to a generator failure also helped reduce CRE (because of additional source term decay time). Twelve individuals received greater than 100 mrem exposure, two of whom received greater than 200 mrem exposure, and no individuals received greater than 300 mrem. There were three Personnel Contamination Events, none of which was significant.

For Refueling Outage 1 R23, CRE performance was very good, posting the lowest CRE ever achieved for a Unit 1 refueling outage. The station originally set a CRE goal of 21.250 person-4.10-3

rem, reduced that goal to 18.350 person-rem early in the outage, and achieved an actual CRE of 18.332 person-rem total for the outage. The low CRE was attributed to ongoing activities to reduce the Reactor Coolant System source term, radiation worker engagement, work efficiencies, and proper staffing numbers.. Additionally, it was more difficult to achieve very low CRE numbers on Unit 1 versus Unit 2 because of design differences on Unit 1 as well as the fact that the Unit 1 source term was higher due to a significant release of Cobalt-60 into the Reactor Coolant System that occurred on Unit 1 a few years ago.

The DCISC reviewed the status of the station's As Low As Reasonably Achievable (ALARA)

Program. For the most recent Refueling Outage 1 R23, the ALARA Program had reviewed and approved two High Radiation Risk Plans, one for routine work being performed on the Lower Transfer Canal and one for routine work performed on the In-core Instrument Seal Table. Those two high radiation risk activities were typically required to be completed during all Refueling Outages. Regarding the distribution of exposures to individual radiation workers during the outage, the data showed that 39 radiation workers incurred exposures greater than 100 millirem, 7 radiation workers incurred exposures greater than 200 millirem, and the highest exposure incurred by a single radiation worker was 379 millirem. The DCISC judged this to be good performance in keeping individual radiation worker exposures as low as feasible.

DCISC personnel also toured the Unit 1 Containment during Refueling Outage 1R23. Personnel were appropriately briefed on radiation conditions inside Containment using Radiation and Contamination Survey Forms and were instructed on the proper use of radiation dosimetry and how to dress in the anti-contamination protective clothing. DCISC personnel toured the following levels and areas of Containment:

Elevation 91: Basement level - Containment Sump and Debris Screens Elevation 115: Steam Generator, Reactor Coolant Pump bases/supports, and Incore Instrumentation Seal Table Elevation 140: Main level with Reactor Cavity, Reactor Head Stand Ongoing outage activities in Containment included reinstalling the Reactor Internals and Head, draining and cleaning the Reactor Cavity, several valve replacements, and component testing. The work appeared orderly and safe. Radiation Protection personnel were monitoring radiation levels and personnel both inside Containment an:d remotely.

The DCISC reviewed the status of non-outage matters within the RP Department and was provided a copy of the RP Department 2021 Excellence Plan. The Excellence Plan included the following focus items for the department:

Maintaining RP Fundamentals and Proficiency Using Human Performance tools Aligning to industry best practices and clear standards Seeking opportunities to gain efficiency through technology Regarding staffing in the RP Department, staffing in the department was not forecasted to be a problem as the date for cessation of power operations approaches. The DCISC concluded that the 4.10-4 I

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I Department Excellence Plan was focused on appropriate items, and staffing was being appropriately managed. Recent reviews by Quality Verification, the Institute for Nuclear Power Operations, and the NRC did not identify any issues or concerns in the RP Department.

Radiation Protection Department performance during Refueling Outage 2R22 was exceptional, achieving an industry best Collective Radiation Exposure of 10.7 person-rem for the outage. Radiation Protection Department performance during Refueling Outage 1R23 was very good, achieving a Unit 1 best Collective Radiation Exposure of 18.3 person-rem for the outage. The Department Excellence Plan was focused on appropriate items, and staffing was being appropriately managed. Overall performance of the department was good, and the As Low As Reasonably Achievable (ALARA) Program continued to be managed well.

Meteorological Information and Dose Assessment System (Volume II, Exhibit 0.5, Section 3.11)

MIDAS is a computer software program that is used to predict the path and magnitude of radiation releases to the surrounding environment caused by an accidental radiation release into the air from the plant.

The output of the MIDAS software is used by DCPP to make protective action (sheltering, evacuation, etc.) recommendations for protection of the public to governmental authorities (i.e., the San Luis Obispo County Office of Emergency Services). The DCISC found that no significant changes had been recently made to the MIDAS software, but nearly all of the hardware on which the software operated had been replaced. The data storage and software operating servers were replaced in 2019, and this change resulted in slightly faster and much more reliable operation.

The only significant issue that continued to occur on the system was a phenomenon referred to as **port exhaustion" which infrequently occurs on Windows-based servers.

This issue could render a server unable to communicate for a short time period and requires a restart of the server to correct the problem. The station then reviewed the consequences of the issue and concluded that they were manageable in that the resulting short outages (less than 30 minutes) did not have significant impacts upon the required uses of the system.

The DCISC also reviewed the circumstances around a weakness identified in Unified Dose Assessment Center performance during the evaluated Emergency Preparedness exercise conducted in September 2021 (SAPN 51124005). The key problem was that dose assessment personnel using MIDAS failed to recognize that plant conditions required a manual input of Steam Generator level into the software and users were not familiar with using the advanced features available in the software to do so. As a result, an inaccurate dose assessment was generated and provided to the Emergency Director. To correct the problem, additional training was conducted with users of the software, and procedural enhancements were made to clarify usage of the software.

DCPP continued to properly maintain and use the MIDAS software system for predicting the magnitude and path of airborne radioactive plumes from the plant in the event of an emergency. Problems in software usage that occurred during the September 2021 Emergency Response exercise had been appropriately addressed.

4.10.3 Conclusions and Recommendations 4.10-5

==

Conclusions:==

The DCPP Radioactive Effluent Release Program and the Radiological Environmental Monitoring Program appeared satisfactory in calculating, monitoring, and measuring radioactivity in the environment surrounding DCPP. During 2020, there were no abnormal releases of radioactivity or abnormal levels of radioactivity detected. DCPP site operations had no significant radiological impact on the health and safety of the public or the environment, and radioactive releases were far below regulatory limits. DCPP continued to properly maintain and use the MIDAS software system for predicting the magnitude and path of airborne radioactive plumes from the plant in the event of an emergency.

Radiation Protection Department performance during Refueling Outage 2R22 was exceptional, achieving an industry best Collective Radiation Exposure of 10. 7 person-rem for the outage. Radiation Protection Department performance during Refueling Outage 1R23 was very good, achieving a Unit 1 best Collective Radiation Exposure of 18.3 person-rem for the outage. The Radiation Protection Department Excellence Plan was focused on appropriate items, and overall performance of the department was good.

Recommendations: None 4.10-6 I

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I 4.11 Quality Programs 4.11.1 Overview and Previous Activities The DCISC has followed DCPP's quality programs continuously since 1990. During the previous reporting period, the DCISC reviewed the follo~ing topics related to quality programs at two Fact-finding Meetings and one Public Meeting:

Meeting with Quality Verification Director Quality Verification Audits Quality Verification's Perspective on Plant Performance The DCISC concluded the following during the previous reporting period:

The DCPP Quality Performance Assessment Report and Quality Digest appeared to be effective tools for reporting performance in the Quality Verification area. DCPP's Quality Verification Audit Program appeared satisfactory in that audits were appropriately scheduled and performed to determine the effectiveness of various departmental and functional activities in meeting quality requirements.

4.11.2 Current Period Activities During the current period, the DCISC reviewed quality programs at three Fact-finding Meetings and one Public Meeting. The following topics were reviewed:

Software Quality Assurance Program Quality Verification Audits and Assessments Quality Verification's Perspective on Plant Performance Software Quality Assurance Program (Volume II, Exhibit D.2, Section 3.7)

Procedure CF2.ID2, "Software Configuration Management for Plant Operations and Operations Support," was provided to and reviewed by the DCISC. This was the overall SQA procedure for plant and security equipment. The procedure was extensive and contained requirements both for the design and implementation of new digital systems as well as for the maintenance of existing digital systems.

Newly developed software applications and revisions to existing plant applications are controlled by their individually prepared and approved SQA Plans. In the form of a procedure, an SQA Plan's purpose is to provide requirements and guidelines for the design, development, modification, and documentation of the application software. It provides for the overall responsibilities, definition of terms, and general instructions for developing and maintaining the application software. Additionally, the DCISC reviewed two SQA Plans, two Design Control Packages (DCPs), and a diagram providing an overview of digital systems at DCPP. The SQA Plans and DCPs appeared satisfactory and well developed.

4.11-1

The DCPP Software Quality Assurance (SQA) Program was split into two significant parts. The first part of the SQA program was administered by the Digital Systems group and manages digital assets that are a part of plant equipment. This plant equipment portion of the SQA program provided a comprehensive process to develop and manage individual system SQA plans which ensured quality and maintained configuration during the development and maintenance of power plant related software applications. Applications covered in this program included those such as Plant Process Monitoring (scan, log, and alarm), Plant Process Control, and any other application with a safety, security, or Emergency Planning function.

If a change was required to an existing digital system, the change would be governed by a Design Change Procedure (DCP) that would be implemented by the Engineering Department. A part of the DCP would contain an implementation plan that would cover how verification and validation of software changes would be performed under the SQA Plan. Before implementing any software changes, any proposed change would be examined for possible adverse effects of the change, and testing would be performed on a development system. (A development system contains hardware that duplicates that installed in the plant, but the development system is not connected to any actual plant equipment.) Usually, the amount of testing required for any change would be based on a review of the verification and validation testing preformed during the original installation of the system.

The second part of the SQA program was managed by the Information Technology Department which was responsible for business-related software that was used in plant activities but does not directly support power plant operations. Examples of applications included in the program were commercial off-the shelf software, databases and spreadsheets, project management and work scheduling software, and other vendor-provided products. The program was controlled by a plant procedure CF2.ID3, "Software Management for Business Information Computer Systems." The procedure required that applications not considered related to plant systems should be screened to determine if a SQA Plan was required. The key criterion for determining if an SQA Plan was required was whether the application or system fulfilled a critical function. A critical function was further defined as one whose failure could: a) affect safety-related systems or functions, b) affect the quality of operational, engineering, or maintenance decisions, or c) result in significant financial loss. SQA Plans prepared for business-related software were required to include many of the same elements as the SQA Plans prepared for plant systems, as discussed above.

DCPP's Software Quality Assurance Program appeared comprehensive and designed to assure computer software that could affect the safety of plant operations was developed, maintained, operated, and changed in an appropriately controlled fashion.

Quality Verification Audits and Assessments (Volume II, Exhibit D.7, Section 3.13, and Exhibit D.8, Section 3.5)

The DCISC reviewed the results of recent QV audits and upcoming audit activities. Audits completed in 2021 and early 2022 with their results were as follows:

Audit Topic Findings Deficiencies Recommendations Chemistry and Environmental Ops

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• • • -------------------------------------~

Fitness for Duty 0

1 0

Emergency Preparedness (2021) 3 4

4 Fire Protection 2

6 4

Applied Technology Services 0

1 0

Special Processes 2

5 3

Cyber and Physical Security 2

6 5

ISFSI and Fuel Management 2

3 3

Corrective Action Program 1

3 2

Engineering and Maintenance Rule 5

5 3

Emergency Preparedness (2022) 0 1

2 Radiation Protection 1

5 3

All of the above findings, deficiencies, and recommendations were entered into the Corrective Action Program (CAP). At the time of the DCISC's reviews, no corrective actions were in an "escalated" status due to deficient or late corrective actions. The QV Department had observed significant improvements in performance for the Emergency Preparedness and Operations Departments over the last year. The schedule for upcoming audits for the remainder of 2022 was as follows:

Audit Topic Procurement Operations Activities Security/Cyber Security Accredited Training Maintenance Quality Assurance Programs Planned Date (2022)

February (due to start within 90 days)

April June June July August DCPP received the report of its biennial evaluation by the Nuclear Industry Evaluation Program (NIEP). The NIEP evaluation satisfied the regulatory requirement for an independent audit of selected functions of DCPP's Quality Assurance Program under 10 CFR 50 Appendix B. Its purpose was to determine if the selected independent oversight functions were adequately developed, documented, and effectively implemented. The DCISC reviewed a copy of the evaluation (dated February 14 - 17, 2022) and found that it concluded that DCPP's independent oversight functions were effective. Four deficiencies and four recommendations were entered into the CAP, with most being identified in the area of performance of and documentation for Quality Control Inspections. Based on the number and quality of audit reports along with the results of the NIEP evaluation, the DCISC concluded that DCPP's Quality Audit program was being effectively implemented.

In addition to the audit program, the QV Department performed both ongoing assessments of overall station performance and detailed assessments on individual issues as selected by QV or requested by station management. The results of the QV Department's ongoing assessments were published in a monthly Quality Digest and a more detailed Quality Performance Assessment Report (QPAR) published approximately every four months. At the time of the DCISC's review, two of the thirteen areas covered in the QPAR were rated yellow (not meeting expectations in some areas) and the rest were rated as green (consistently meeting expectations).

4.11-3

Assessments of specific issues at the station prepared by QV during 2021 included:

Safety Issue Resolution Engineering Evaluations Equipment Reliability Refueling Outage 2R22 Early Start Refueling Outage 2R22 Human Performance Trend Engineering Work Product Review Team Instrumentation and Controls Maintenance Performance Trend Security Lighting Regarding staffing, groups handling Quality Inspections and Vendor Audits were both fully staffed. The Nuclear Audit and Assessment group was staffed at five of seven auditor positions filled with two positions recently vacated due to a transfer and a retirement. The Department was monitoring the effects of turnover at the station but had not seen any impacts to date. The DCISC concluded that the assessment activities of the QV Department were being effectively performed and provided a valuable independent perspective on station performance.

The DCPP Quality Verification Audit Program was being effectively implemented in that audits were being appropriately scheduled and performed to determine the effectiveness of various departmental and functional activities in meeting quality requirements.

The assessment activities of the Quality Verification Department were also being effectively performed and provided a valuable independent perspective on station performance.

Quality Verification's Perspective on Plant Performance (Volume II, Exhibit 8.9)

The following is a summary ofDCPP's presentation on this topic at the DCISC's June 2022 Public Meeting: During the first period of 2022, the Quality Verification group found that DCPP exhibited traits reflecting a strong nuclear safety culture, effectively implemented the Quality Assurance Program, and met regulatory requirement and commitments.

Improvement was observed in three key departments, Engineering, Maintenance and Operations. This period also included successful completion of Refueling Outage 1 R23 and the station remained focused on workforce management and industrial safety. Highlights of performance in each functional area were as follows:

Operational Focus - increasing communication on equipment issues and leveraging new processes to implement prioritization, including an improvement in the ability to timely identify and correct trends.

Maintenance - increasing the use of error reduction tools and implementation of the crew notebook and management review meetings, similar to those used by Operations. Crew notebooks function to document and track, in an electronic database format, observations by their leadership of an individual's performance in the field to identify and provide feedback on areas for improvement.

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I Engineering - good engineering support during IR23 and effective and timely resolution of issues identified in the 2021 Engineering audit.

Industrial Safety - progress included reestablishing a station level safety oversight committee and improving peer-to-peer coaching.

Workforce Management -

implementation of processes to ensure appropriate qualifications and proficiencies were maintained and knowledge transfer included oversight and participation by Quality Verification observers in the knowledge transfer working groups.

4.11.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's Software Quality Assurance Program appeared comprehensive and designed to assure computer software was developed, maintained, operated, and changed in an appropriately controlled fashion. The DCPP Quality Verification Audit Program was being effectively implemented, and the assessment activities of the Quality Verification Department were being effectively performed.

Recommendations: None 4.11-5

4.12 Nuclear Fuel Performance 4.12.1 Overview and Previous Activities The DCISC has been following performance of nuclear fuel and fuel-related matters at DCPP since its beginning in 1990. The Committee receives regular reports on nuclear fuel performance and any problems from PG&E both in fact-finding and public meetings and as input to the annual report.

DCISC follows-up on problems and activities in its fact-finding meetings at DCPP and PG&E Headquarters.

DCPP fuel reliability is the most important fuel attribute monitored during operation. It is important to assure that the fuel integrity is preserved to avoid fission product leakage into the reactor coolant system (RCS) and ultimately into RCS cleanup and support systems resulting in increased personnel dose, radioactive waste and potential off-site releases.

Since the DCISC was formed in 1990, fuel reliability had been excellent until November 1994 when Unit 2 fuel began to show signs of leakage and experienced localized fuel damage. Unit 2 has had several additional fuel leaks since then. Leakage is measured by the amount of radioactivity in RCS samples, with a current goal of less than 5.0 x 10-4 microuries (µCi) of Iodine-131 per gram of coolant. The following depicts the RCS radioactivity trend for a five-year period:

Reactor Coolant System Radioactivity (microuries/gram of coolant Iodine-131)

Period 17-18*

18-19 19-20 20-21 21-22*

Goal (µCi/gm) 5.0 X 10-4 5.0 X 10-4 5.0 X 10-4 5.0 X 10-4 5.0 X 10-4

• Through June 2022 Unit 1 Actual (µCi/gm) 1.0 X 10-6 1.0 X 10-6 1.0 X 10-6 1.0 X 10-6 l.0xl0-6 Unit2 Actual(µCi/ gm) 4.2 X 104 4.2 X 104 4.2 X 104 4.2 X 104 4.2 X 10-4 The DCISC reviewed the following specific nuclear fuel performance during the previous reporting period:

Nuclear Fuel Performance The DCISC concluded the following in the previous reporting period:

The DCPP nuclear fuel has for many years performed flawlessly with no defects or leakage.

Unit 1 has performed without defects since 2011, and Unit 2 since 1991. This is excellent performance. DCPP is designing their fuel for the remaining operating life with lower enrichments and shorter cycles.

4.12.2 Current Period Activities 4.12-1 I

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I The DCISC reviewed the following nuclear fuel performance during the 2019-2020 period.

Nuclear Fuel Performance Nuclear Fuel Performance (Volume II, Exhibit 0.9, Section 3.4)

Unit I fuel was in Cycle 24 and had completed 19 cycles since 1991 with no fuel defects. Unit 2 fuel was in Cycle 23 and had experienced no defects since 2011. This was excellent performance.

During the recently completed Refueling Outage 1 R23, no new debris was found either in the Reactor Vessel or in the fuel assembly nozzles and grids.

Fuel inspections performed via underwater cameras on the four sides and bottom nozzles of all fuel assemblies also found no abnormalities.

Looking ahead, core design will be optimized to make the most use of existing fuel assemblies across shorter cycles. Core design continued to be a joint effort by DCPP and Westinghouse personnel, and DCPP was planning to stay with the same fuel design from the same supplier (Westinghouse) for the remaining years of operation. During refueling outages, contract personnel from Westinghouse continued to be used for most fuel handling activities under the supervision of DCPP Licensed Operators.

All fuel handling equipment performed well during the recent Refueling Outage I R23.

The FFT inquired about staffing in the Reactor Engineering group, and DCPP reported that the group consisted of four engineers and one supervisor. This was down from six engineers a few years ago, and recent benchmarking found that DCPP's current staffing level was consistent with staffing numbers at other nuclear power plants.

4.12.3 Conclusions and Recommendations

==

Conclusion:==

The DCPP nuclear fuel has for many years performed flawlessly with no defects or leakage. Unit 1 has performed without defects since 2011, and Unit 2 since 1991.

This is excellent performance. DCPP is designing their fuel for the remaining operating life with lower enrichments and shorter cycles.

Recommendations: None 4.12-2

4.13 Equipment Reliability 4.13.1 Overview and Previous Activities Aging-related degradation is the gradual degradation in the physical characteristics of a system, structure, or component (SSC) which occurs over time and use, and which could impair the ability to perform its design functions. The purpose of the Equipment Reliability Program is to ensure that the plant continues to operate safely and within its design and licensing bases throughout its life through the process of involving engineering, operation, and maintenance in activities to control age-related degradations or failures of SSCs to within acceptable limits. The scope of the SSCs to be covered by the program continues to evolve and expand, and DCPP has established an Equipment Reliability Program with a dedicated Program Director.

During the previous reporting period, the DCISC reviewed the following topic related to Equipment Reliability at one Fact-finding Meeting:

Equipment Reliability Process The DCISC concluded the following during the previous reporting period:

DCPP's Equipment Reliability overall was Green (Healthy) with Unit 1 showing strong performance, and Unit 2 needing some corrective actions to meet plant expectations. DCPP had implemented a plan to improve Unit 2 ER by the end of 2020.

4.13.2 Current Period Activities During the current period, the DCISC reviewed Equipment Reliability programs at one Fact-finding Meeting. The following topic was reviewed:

Equipment Reliability Process Equipment Reliability Process (Volume II, Exhibit D.3, Section 3.6)

The DCISC reviewed DCPP's Equipment Reliability (ER) program. Overall, DCPP"s indicators for ER performance were Yellow (Needing Improvement) due primarily to unanticipated equipment failures, mainly vibration issues in the Unit 2 Main Generator. ER was considered to be on an improving trend, and DCPP was continuing to focus on ER through its 2021 ER Excellence Plan. The DCISC reviewed the Station ER Policy, the ER Excellence Plan, and a

• • What Excellence Looks Like" (WELL) sheet for ER. The ER Excellence Plan and WELL sheet were intended to create alignment of maintenance and engineering activities with the Station ER Policy.

The WELL sheets were recently used in a station-wide review that resulted in over 40 observations comparing performance in ER-related activities to the policy over a four-week period. The rate of using the WELL sheets for observations had declined since the initial period, but they continued 4.13-1 I

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I to be used regularly. The results of the WELL sheet observations were being reviewed by an ER Executive Oversight Board who served to function much like a Plant Health Committee but with a focus more on organizational behaviors that support maintaining ER. The DCISC reviewed the ER Excellence Plan and noted that the majority of the action steps had been completed. Although only a few items remained to be performed under the plan, the plan was intended to remain open as a living document to further drive improved performance in ER.

DCPP's Equipment Reliability performance indicators overall were Yellow (Needing Improvement) due primarily to vibration issues with the Unit 2 Main Generator. DCPP continued to work to improve its processes that affect Equipment Reliability, and the trend of Equipment Reliability performance was improving.

4. 13.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's Equipment Reliability performance indicators overall were Yellow (Needing Improvement) due primarily to vibration issues with the Unit 2 Main Generator.

DCPP continued to. work to improve Equipment Reliability, and the trend of Equipment Reliability performance was improving.

Recommendations: None 4.13-2

4.14 Organizational Effectiveness and Development 4.14.1 Overview and Previous Activities The focus of Organizational Effectiveness and Development is centered upon process transformation, process structure, and organizational effectiveness initiatives. DCPP"s cultural change efforts, leadership initiatives and activities, strategic change efforts, etc., are intended to function as interrelated efforts. This focus also supports an industry initiative to review cultural change, leadership issues, and even human performance, under the area of *'organizational effectiveness.'" PG&E uses an annual DCPP Operating Plan to be sure all departments* goals and plant goals have total alignment.

In previous reporting period, the DCISC reviewed the following Organizational Effectiveness topics at two Fact-finding Meetings and two Public Meetings:

Plan of the Weekend Review Meeting Results of 2020 Operating Plan and Key Elements of the 2021 Operating Plan Station Excellence Plan The DCISC concluded the following during the previous reporting period:

A Plan of the Weekend Review meeting was effectively facilitated with crisp and clear informational exchanges across a large number of planned work activities.

DCPP successfully accomplished most of the objectives contained in its 2020 Operating Plan, and the 2021 Operating Plan contained appropriate focus areas with initiatives and key metrics.

DCPP's Station Excellence Plan was a comprehensive, high-level plan aligning departmental and other DCPP plans. The Station Excellence Plan was appropriate for the station and had the potential to provide improved focus for the leaders' efforts in achieving and maintaining excellence.

4.14.2 Current Period Activities During the current period, the DCISC reviewed Organizational Effectiveness at one Fact-finding Meeting and one Public Meeting. The following topics were reviewed:

Management Observation Program Results of 2021 Operating Plan and Key Elements of the 2022 Operating Plan Management Observation Program (Volume II, Exhibit D.1, Section 3.8)

DCPP"s Management Observation Program was a part of the continuous performance monitoring program governed by procedure OM15.ID10, **Performance Monitoring Program," a copy of which was provided and reviewed by the DCISC. DCPP's Management Observation Program continued to be focused on establishing requirements for supervisors to observe employees in the field on a daily basis and discuss their observations with employees in a collaborative fashion.

4.14-1 I

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I Supervisory observations were documented and rolled up into reports that were discussed at departmental Observation Review Meetings (ORMs). The ORMs were typically held bi-weekly to review the results of all observations, and departmental Performance Improvement Coordinators (PICOs) participated in the ORMs. The agenda and results of each ORM were being recorded electronically using a software program designed for group collaboration.

Performance Improvement Coordinators were provided an opportunity via the ORMs to identify significant gaps or trends and initiate further actions in the department or across broader areas of the station. These significant gaps or trends were entered into the corrective action system for tracking and also included in monthly departmental Performance Improvement (Pl) Dashboard reports. Both the identified trends and the monthly PI Dashboards were highly visible to plant management. The DCISC also regularly received and reviewed copies of the departmental PI Dashboards.

DCPP's Management Observation program was being properly implemented with a focus toward first-line Supervisors observing employee activities in the field and reviewing their observations during bi-weekly departmental Observation Review Meetings.

Results of the 2021 Operating Plan and Key Elements of the 2022 Operating Plan (Volume II, Exhibit B.6)

The following is a summary of DCPP's presentation on this topic at DCISC's February 2022 Public Meeting: The Nuclear Generation organization, having previously been combined within the Generation organization, was now its own separate business unit with its own Nuclear Generation Business Plan. DCPP continued to place a priority upon ensuring the continuance of a qualified, skilled and proficient workforce able to carry out day to day operations and maintenance and refueling outages. The Institute for Nuclear Power Operations (INPO) continued to rate DCPP performance as exemplary and improving which is INPO's highest rating and the NRC continues to rank DCPP in Column I of the NRC Licensee Response Matrix, again the highest performance category possible within the nuclear industry. The 2R22 refueling outage in 2021 was completed safely and on schedule and Unit 2 had run reliably since that time. 2022 would have two refueling outages scheduled. There were no disruption of major work activities including refueling outages due to the COVID-19 Pandemic. Completion of the NRC emergency planning evaluated exercise which tested all DPP's emergency response facilities was a major accomplishment and success during 2021 with no risk-significant findings identified. Measurable results from the 2021 Operating Plan were as follows:

Metric DCPP Reliability &

Safety Indicator 2R22 Outage Radiation Exposure Preventable Motor 87.5

<13.3 REM I st Quartile 4.14-2 Actual 92.5 10.8 REM I st Quartile

Vehicle Incidents Days Away, Restricted, or Transferred Cases Lost Work Day Cases Regulatory Findings NRC Reactor Oversight Process 1st Quartile 1st Quartile 1st Quartile 1st Quartile No Significant No Significant Column 1 and no Column 1 and no Cross-cutting issues Cross-cutting issues The Nuclear Generation organization's 2022 Operating Plan was focused upon organizational purpose; meaning, why the organization exists and how that translates to principles including serving the community. This was also reflected in all of PG&E's lines of business through the PG&E True North Strategy Stands which focused on plans and responsibility for safety principles.

Other aspects of the True North Strategy Stands principles included ensuring PG&E provided an enjoyable place to work, which translated at DCPP to planning and producing carbon neutral energy safely and reliability without human performance errors and making that energy available for customers when it is needed. Foremost in maintaining exemplary performance and finishing on top was the requirement to keeping a focus upon maintaining good performance. Integral to that effort were maintaining excellence in equipment reliability, in the use of the Corrective Action Program, and in not accepting any compromises to safety and reliability. The Nuclear Generation leadership model was in accordance with PG&E's Lean Operating System philosophy as it consisted of engaging, enabling and sustaining the workforce and engaging with the workforce in the field to remove roadblocks to allow workers to do their jobs successfully the first time.

The key work projects and initiatives for 2022 for Nuclear Generation included:

Executing two refueling outages ( 1 R23 in March and 2R23 in October).

Preparing for an NRC Evaluated Emergency Planning Exercise (September).

Maintaining industry l st Quartile industrial safety performance.

Focusing on the Pathways Program for retaining, retraining, supporting and redeploying DCPP's employees.

4.14.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's Management Observation program was being properly implemented with a focus toward first-line Supervisors observing employee activities in the field and reviewing their observations during bi-weekly departmental Observation Review Meetings.

DCPP successfully accomplished most of the objectives contained in its 2021 Operating Plan, and the 2022 Operating Plan contained appropriate focus areas with initiatives and key metrics.

Recommendations: None 4.14-3 I

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4.15 System and Equipment Performance/Problems 4.15.1 Overview and Previous Activities During past periods, the DCISC had reviewed the performance and problems of DCPP equipment and systems as well as the actions taken by PG&E to resolve them.

During the previous period (July 1, 2020 - June 30, 2021), the DCISC reviewed the following system and equipment issues:

Containment Concrete Inspection License Amendment Request (LAR) for Auxiliary Feedwater (AFW) System Inspection AFW LAR Status Control Rod Issues Safety System Functional Failures Main Generator Issue & Root Cause Evaluation Reactor Vessel Specimen The DCISC performed the following system/component reviews and/or walk downs with DCPP System/Component Engineers in the previous period:

Compressed Air System Containment Ventilation & Hydrogen Mitigation Systems Nuclear Instrumentation System Radwaste Processing Systems Motor Operated Valve & Air Operated Valve Testing Programs Turbine Generator Health Large Transformer Health Chemical and Volume Control and Emergency Core Cooling Systems Control Room Ventilation System Reactor Protection System Radiation Monitoring System Auxiliary Building Ventilation System In the previous period, the DCISC concluded that DCPP has dealt effectively with most equipment and system problems and is focused on improving system health. DCPP's Plant Health Committee has been improved to focus more on system/component health and meets more frequently, and overall system health has improved.

4.15.2 Current Period Activities 4.15.2.1 DCISC Reviews of System and Equipment Performance and Problems The DCISC reviewed the following system and equipment issues during the current reporting period:

4.15-1

Intake Structure Concrete Inspections Failed Auxiliary Saltwater Pump Motor Root Cause Evaluation Unit 2 Generator Failures Root Cause Evaluation Feedwater Heater Tube Failures Emergency Diesel Generator Follow-up Items Containment Structure Inspections Intake Structure Concrete Inspection Update and Tour (Volume II, Exhibit D.2, Section 3.6)

The DCPP Intake Structure Inspection Program is governed by procedure PEP C-17.14, "Concrete Surveillance Programs for Saltwater Systems." This was provided to the Fact-Finding Team. The program specified that inspections of non-submerged (accessible) areas be performed every two years and that inspections. of submerged areas be performed when accessible during every Refueling Outage. The inspections were performed by a contracted engineering firm which specialized in performing and documenting inspections of concrete structures. The inspectors were required to have a minimum certification as a Level 3 Civil Inspector plus experience specific to the testing methods required by the governing procedures.

The most recent (August 2020) inspection report for non-submerged areas included visual inspections of all accessible areas, hammer soundings for delaminations in selected areas (which included non-degraded areas, degraded areas, and repaired areas), and half-cell potential measurements in limited areas. This included the Auxiliary Saltwater System Pump Vaults. The half-cell potential measurements provided a basis for determining if there was corrosion of reinforcing steel inside the concrete. The report documented the results of the testing using written summaries, tabular results, and drawings.

For Unit l the report showed that 100% of the total 40,450 square foot accessible non-submerged area received visual inspections, and soundings were made on about 31,425 square feet (78%) of the area. The soundings determined that approximately 1,597 square feet (3.9%) of the surface area contained delaminations that required repair and/or further monitoring.

For Unit 2 100% of the 40,450 square foot accessible non-submerged area received visual inspections. About 31,425 (78%) square feet were sounded for delaminations with 2,262 square feet (5.6%) found to be delaminated.

Deficiencies found during the inspection were documented in the Corrective Action Program Notifications and reviewed by Engineering to determine what corrective action would be required.

The corrective actions included recommended repairs of four specific areas, which were prioritized and entered into the work control system in accordance with standards contained in the procedure.

DCPP's intake structure cathodic protection systems performed well in reducing the corrosion of submerged structures. In general, the submerged structures were less susceptible to corrosion and degradation due to the reduction in oxygen levels underwater. The most recent inspection reports for submerged areas on Unit 1, dated December 2020, and Unit 2, dated May 2021, corresponded to Refueling Outages 1 R22 and 2R22, respectively. The sacrificial zinc anodes, connected to the 4.15-2 I

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I internal reinforcing steel were buried in the concrete structure. Those anodes were periodically removed and replaced. Overall, the DCISC FFT concluded that the Intake Structure concrete inspection program was sound, and corrective actions were being properly taken for identified deficiencies.

The DCISC Consultant and the three DCPP personnel performed a walkdown of accessible areas of the Intake Structure. The team toured the areas of the structure identified for repairs, comparing the inspection records with the observed conditions, and found that the inspection records accurately documented the conditions. The group peered through the windows of the Auxiliary Saltwater System Pump Vault Doors. In general, Intake Structure areas were in good condition and appeared to be properly maintained. Recent repairs were satisfactory.

DCPP's concrete inspections and repairs to their Intake Structure appeared comprehensive and effective. The structure was judged to be sound by an expert engineering contractor.

Root Cause Evaluation for Failed Auxiliary Saltwater Pump Motor (Volume II, Exhibit D.3, Section 3.5 and Exhibit D.5, Section 3.1)

On July 5, 2021, operators attempted to perform a routine swap of running ASW pumps. When they started ASW Pump 1-1, a low ground alarm occurred, indicating a possible problem with the pump motor. Operators then aborted the attempted pump start and left ASW 1-2 pump in service.

Investigations revealed that the pump motor heater had been known to have been degraded for about a year and failed during the previous week (based on the stator temperature trend history).

The failed motor heater likely allowed moisture to build up on surfaces inside of the pump motor which caused the partial ground condition and alarm. Although it was possible that the pump could have continued to run and the ground might have cleared after the motor heated up, operators conservatively declared the pump inoperable and initiated maintenance activities to replace the pump motor. The motor was successfully replaced and returned to service about three days later.

The purpose of this meeting was to review the final Root Cause Evaluation (RCE).

The DCISC reviewed a copy of the final RCE Report, "Multiple Grounds on ASW Pp 1-1 Start,"

Revision 0. In the past, safety-related motors had been typically overhauled every three refueling outages, but this periodicity was extended to every four refueling outages in 2016. This extension was based on guidance from the Electric Power Research Institute that motor overhauls should occur on a ten-year (approximately four refueling outages) frequency. The ASW Pump motors were located indoors; however, their cubicles were provided unfiltered air directly from the outside near-ocean environment at the intake structure. The extended overhaul frequency provided an opportunity for increased buildup of mineral deposits inside the motor from the ocean air, and this potential environmental impact was not recognized or evaluated at the time of the periodic maintenance extension. In part, engineers reviewing the extension did not recognize that although the motor was physically located indoors, it was essentially subjected to an outdoor environment due to the forced flow of outside air directly into the motor's location. The RCE concluded that the primary root cause for the motor failure was this "unrecognized risk to ASW motor reliability with a motor heater failure given the operating environment and the potential for undetectable quantities of contamination."

4.15-3

To address the programmatic deficiency identified in the primary root cause, procedure ERl.lDl, "Equipment Reliability Process," was revised to add a requirement for a periodic review by select managers (conducted quarterly at a minimum) of new or updated preventative and corrective maintenance activities associated with critical equipment. This review was initiated to ensure equipment reliability challenges were mitigated by identifying possible unrecognized risks, ensuring correct work prioritizations, and ensuring robust monitoring was being implemented and tracked where appropriate. These periodic reviews were now being performed quarterly by managers from Maintenance, Operations, Engineering and Work Control.

The Root Cause Evaluation for a June 2021 Auxiliary Saltwater Pump 1-1 motor ground was comprehensive, and appropriate corrective actions were initiated to prevent recurrence.

Feedwater Heater Tube Failure Root Cause Evaluation (Volume II, Exhibit D.4, Section 3.5 and Exhibit D.6, Section 3.12)

The DCPP feedwater heaters are shell and tube heat exchangers which take low-grade ( extraction) steam from the steam turbines to pre-heat feedwater prior to its entering the steam generators. This increases the thermal efficiency of the plant. Feedwater runs through the heat exchanger tubes to be heated from steam on the shell side. DCPP uses six cascading stages of preheat with spent steam sent to the condenser.

During startup from Outage 2R22 on October 15, 2021, FWH 2-5B was exhibiting indications of tube leakage. Power in Unit 2 was lowered to 90% to isolate the FWH to perform inspection and repair. The reactor was then manually tripped because of high FWH level. Significant tube failure of this nature significantly overwhelms the FWH drain system, requiring reactor shutdown to mitigate further damage.

A borescope examination showed a tube failure and other tube damage. Eddy Current Testing (ECT) showed the extent of condition, which was repaired. The unit was returned to power but shut down again due to additional tube leak indications. Further 100% ECT indicated additional repairs were needed, which were performed, and the unit was brought back up to power with extended FWH monitoring. The unit has operated satisfactorily since then.

A Root Cause Evaluation (RCE) team was established and completed its report in mid-December.

The purpose of this January 2022 Fact-finding visit was to review the RCE, which was provided to the FFT prior to the meeting. The RCE determined the probable cause to be "Excessive unsupported tube lengths caused by a breach in the Drain Cooler shroud [which] led to fatigue fracture of the FWH tubes." (The RCE noted that a probable cause, rather than a root cause, was developed due to the limited accessibility of the FWH internals and availability of tube material evidence. Tube samples were not available for metallurgical analysis to confirm the failure mechanism.) Corrective actions included the following:

1. Determine which FWHs require additional inspections or preventive tube plugging and implement same 4.15-4 I

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2. Implement additional FWH system monitoring to identify a potential Drain Cooler shroud breach on all 24 FWHs with an integral Drain Cooler

3. Identify additional leak detection monitoring in the most vulnerable FWHs and revise Operator Rounds to include additional FWH data points

4. Revise the Heat Exchanger Program to include assessment of unsupported tube lengths and to implement preventive tube plugging

5. Document reassessment oflong-range plan for FWHs based on this RCE

6. Revise FWH Removal From and Return to Service to close the tube side inlet and outlet simultaneously when isolating for a leak The RCE and corrective actions appeared satisfactory to the DCISC FFT. DCPP made a presentation on this event at the DCISC February 2022 Public Meeting.

DCPP experienced significant Feedwater Heater (FWH) tube failures in FWH 2-5B in mid-October 2021, which caused Unit 2 to be shut down twice to perform inspections and repairs.

The unit has been operating normally with extended FWH monitoring since the final repairs were made. The DCPP Root Cause Evaluation and planned corrective actions appeared satisfactory.

Emergency Diesel Generator System Follow-up Items (Volume II, Exhibit D.5, Section 3.8)

The first issue that the DCISC inquired about was the status of the Cause Evaluation (CE) for a significant fuel oil leak that occurred on EDG 2-3 during a maintenance run in June 2021. The EOG was shut down and the leak was successfully repaired. Following the failure, the size of the leak was evaluated and found to have rendered the EDG unable to run for the duration of time needed in the accident analyses, and the failure was therefore classified as a Maintenance Rule Functional Failure and a Critical Equipment Clock Reset. The Cause Evaluation concluded that the probable cause of the leak was engine vibration along with thermal and pressure cycling during normal operation which resulted in the 1 R "banjo bolt" torque working loose over time. The DCISC noted that an alternative cause could have been insufficient initial torquing of the bolt. The "banjo bolts" were fasteners that held fuel oil fittings called "banjo fittings" in place against the 18 fuel injection pumps on each EDG as shown below:

As corrective action for the issue, maintenance procedures were revised to add steps to regularly check the torque of the banjo bolts. Additionally, banjo bolts on the other EDGs were checked to ensure proper torquing. Across all of the remaining engines, approximately six bolts were found with slightly less than the required torque.

Following completion of the CE, additional investigations had been initiated primarily in response to a very high level of interest from NRC Resident and Regional Inspectors. Further investigations found some inconsistencies in the history of the types of material used in the banjo bolt gaskets.

The second issue was the failure ofEDG 2-3 to achieve the required frequency of electrical output during a surveillance test on July 22, 2021. This failure was determined to be one that would prevent the EDG from performing its safety function during an accident, and Licensee Event 4.15-5

Report 2021-01 for Unit 2 was submitted to the NRC to report the occurrence of this event to the NRC. It was noted in the report that the required overall safety functions were maintained by the other two Unit 2 EDGs which were not affected by the failure, and the EDG's frequency could have been adjusted manually to correct the issue if needed during an accident.

During a previous maintenance period for EDG 2-3 in June 2021, technicians performed tuning on the EDG governor to address minor load and frequency oscillations that had been noted during previous EDG tests. The governor tuning was successfully completed; however, post-maintenance testing did not include checking EDG output frequency during all modes of operation.

Specifically, the frequency for isochronous mode operation was not checked following the governor tuning during the June maintenance. When the EDG was next tested in July, it was discovered that the frequency for isochronous mode operation was less than the minimum required value (58.9 Hz vs. 59.5 Hz). The isochronous mode setpoint was successfully adjusted, and the EDG returned to service the following day. Later analysis of the event concluded that the EDG would not have been able to perform its designed functions in automatic during the time period between the June and July maintenance activities. The cause of the event was concluded to be a human error in failing to specify adequate post-maintenance testing activities following the June governor tuning.

Maintenance procedures were revised, and the involved individuals were coached and provided additional training on EDG governor systems.

Initial corrective actions taken to date in response to a June 2021 fuel oil leak on Emergency Diesel Generator 2-3 appeared appropriate, but the DCISC should receive a briefing on the final causes and corrective actions for the leak at an upcoming public meeting. A July 2021 failure of the same Emergency Diesel Generator to achieve the required electrical output frequency during a surveillance test was caused by a human error in specifying adequate post-maintenance test activities following an earlier maintenance activity. The issue was properly investigated, and appropriate corrective actions were initiated.

Containment Structure Inspections (Volume II, Exhibit D.9, Section 3.3)

Each Containment Structure consisted of a concrete exterior including:

A 14 ft-6 in thick, 153 ft diameter reinforced base mat A 3 ft-8 in thick, 140 ft inside diameter and 142 ft high reinforced concrete cylindrical wall A 2 ft-6 in thick, 140 ft inside diameter reinforced concrete hemispherical dome roof Each Containment Structure also included a steel liner consisting of:

A 1/4 in thick mild carbon steel plate placed on top of the Containment base mat A 3/8 in thick mild carbon steel plate covering the inside surface of the Containment shell Penetration sleeves and local reinforcement of the liner around penetration openings Anchorage system of the liner to concrete The Containment Structure overall had a design pressure of 47 psig. at 271 °F, and was designed to sustain a 7.5 magnitude Hosgri Earthquake acceleration spectrum peak of 0.75 g. Additional loads were incorporated into the design to account for wind, pipe rupture, jet impingement, and 4.15-6 I

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I missile impacts. The DCPP Containment Structure contained a net free volume of 2.55 million cubic feet and had a Technical Specification maximum design basis leak rate of 0.1 weight % per day used for accident calculations.

The Containment Structure was subject to the following tests/inspections:

Visual inspections of Containment concrete surfaces per 10 CFR 50, Appendix J, and American Society of Mechanical Engineers (ASME)Section XI Code. This 100%

inspection was required to be performed every five years. The most recent inspections were performed in 2021 for both units, and the results were reviewed by the FFT as discussed below.

Visual inspection of the steel liner plate inside the Containment as per 10 CFR 50, Appendix J and ASME Section XI Code. These inspections were required to be performed every 40 months.

Containment Integrated Leak Rate Tests (ILRTs) as per 10 CFR 50, Appendix J. These tests were performed every 10 years. In an ILRT, large portable air compressors are brought to the site and used to pressurize the containment building a test pressure of 42 psig. The most recent ILRTs were conducted in June 2019 on Unit 1 (Refueling Outage 1R21) and April 2018 on Unit 2 (Refueling Outage 2R20). There were no indications or problems found during the most recent ILRTs, the results of which were previously reviewed by the DCISC as a part of its routine activities following refueling outages.

During the 2021 inspections, the majority of the concrete surface inspections were performed using a high-resolution camera mounted on a remotely controlled drone, which was the first time this advanced inspection system had been used. The drone's camera was first tested and validated that it could record cracks and defects as well or better than a human eye performing the same inspection. Then the drone was flown around all surfaces of the containment recording pictures of the concrete surfaces that were later reviewed by technicians qualified to perform visual inspections in accordance with the ASME Section XI Code. Use of the drone had industrial safety benefits as there was no need for an individual to rappel down the sides of the Containment as was done in the past.

The ASME Section XI Code and DCPP's procedures called for classifying any observed indications of defects according to an approach using two tiers of acceptance criteria. (Governing procedure NDE VT 3C-l, "VT-3C Visual Examination of the Containment Concrete Shell,"

Revision 6, was provided to the FFT via its inclusion as an Appendix in the inspection reports provided.) Indications within the first tier (lowest) criteria could be judged as inconsequential by the inspector.

Indications exceeding the first-tier criteria were evaluated by a responsible Professional Engineer to ascertain if second-tier criteria were exceeded. Any indication exceeding the second-tier criteria required that further evaluations be performed to confirm that structural integrity was being properly maintained. Most indications fell into the categories of passive cracks, leaching, or deteriorated form tie repairs.

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For Unit 1, 28 indications were judged to exceed the second-tier criteria, of which 26 had been identified and reviewed during previous inspections. The two newly identified indications were entered into the Corrective Action System for further evaluation, and DCPP provided copies of the Notifications to the FFT (SAPNs 51153639 and 51153681). Additional reviews found that both new indications were acceptable as is, and no additional actions were required other than to monitor the indications during future inspections. For Unit 2, 20 indications were judged to exceed the second-tier criteria, of which all 20 had been identified and reviewed during previous inspections. For both units, no indications required additional corrective actions and all indications were judged to be acceptable for continued operation until the next regularly scheduled inspection.

The DCPP Containment Structures were sound and appeared to have no safety issues or concerns. The structures satisfactorily passed all recent visual concrete inspections and integrated leak rate tests.

4.15.2.2 DCISC Reviews of DCPP Systems/Components The DCISC performed the following system/component reviews and walk downs with DCPP System Engineers:

Emergency Diesel Generators Plant Health Committee Reactor Coolant System Health Auxiliary Feedwater System Refueling Equipment Health Digital Systems Update Transmission System Direct Current Power System Containment Spray System Emergency Diesel Generators (Volume II, Exhibit D. l, Section 3. 9)

The EDGs are safety-related pieces of equipment whose functions are as follows:

To furnish sufficient electric power to mitigate a design basis accident in one unit and safely bring the other unit to cold shutdown when both the 230k V and 500k V off site power sources are unavailable.

To act as a backup source of power to enable the reactor to continue to produce power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> whenever there is no accident condition, but one of the two offsite power sources is inoperable.

To furnish power sufficient for an emergency shutdown of the plant whenever the offsite power source~ are not available.

The EDG Fuel Oil Supply system has enough fuel capacity to provide seven days of onsite power generation: (a) in order to operate the minimum required Engineering Safety Features equipment 4.15-8 I

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I following a design basis Loss-of-Coolant Accident for one unit, and the equipment in the second unit is in either the hot or cold shutdown condition, or (b) when the equipment for both units is in either the hot or cold shutdown condition.

Each nuclear operating unit is supported by three EDGs dedicated to the respective unit, and the EDGs can be cross connected to the other unit using temporary cables. Each EDG set is provided with two 100% capacity starting air trains, with each train having two starting air motors. The EDGs are rated to deliver approximately 2,600 kW on a continuous basis and are designed to start automatically on any of the following signals:

A Safety Injection signal from either Train A or Train B of the plant protection system.

Undervoltage on the preferred offsite power sources to each of the 4160V vital buses, any one of which starts its respective diesel.

Undervoltage on any of the vital 4160V buses, any one of which starts its respective diesel.

Unit 1 Unit 1 's EDGs were classified as Green (Healthy) with the following issues challenging system health:

The EDG Local Control Panel alarm relay modules are obsolete with limited replacement modules available. A design change has been initiated to facilitate future replacements with a newer module design on an as-needed basis.

EDG Fuel Oil Day Tank level switches fail often during testing. Alternative designs are being evaluated for the level switches.

Fuel Oil Transfer Pump motors are aging prematurely due to an increase in their required duty cycle. Replacements are scheduled for May 2022.

A small oil leak on the EDG 1-1 Lube Oil Heat Exchanger was recently repaired. The leak did not affect operability.

Unit2 Unit 2's EDGs were classified as Red (Unhealthy) due primarily to a Critical Equipment Clock Reset that occurred in June 2021 ( described below). The following issues were challenging system health:

A significant fuel oil leak occurred on EDG 2-3 during a maintenance run in June 2021, and the EDG was shut down to repair the leak. The size of the leak was judged to have rendered the EDG unable to run for the duration of time needed in the accident analyses, and the failure was therefore classified as a Maintenance Rule Functional Failure and a Critical Equipment Clock Reset. The Cause Evaluation had not been completed as of the date of the FFT's meetings. This failure was the primary driver for the Red (Unhealthy) 4.15-9

system health classification, and it was forecasted that the system health would return to Green (Healthy) at the end of the third quarter of 2021.

The EDG control system components (Woodward motor-operated potentiometer governors) were no longer available and considered obsolete. Modifications to upgrade the governors were completed on EDG 2-2 in October 2019. An alternative plan was approved that canceled replacement of the governors on EDGs 2-1 and 2-3. Instead, portions of the old governor systems were retained, evaluated by Engineering, and approved for use as replacements on EDGs 2-1 and 2-3, should future problems occur.

This action to make spares available would address the obsolescence issue for the two remaining EDGs, which was the primary purpose of the replacement modifications.

The EDG Local Control Panel alarm relay modules are obsolete with limited replacement modules available. A design change has been initiated to facilitate future replacements with a newer module design on an as-needed basis.

EDG Fuel Oil Day Tank level switches fail often during testing. Alternative designs are being evaluated for the level switches.

Fuel Oil Transfer Pump motors are aging prematurely due to an increase in their required duty cycle. Replacements are scheduled for May 2022.

A previously reviewed issue regarding small load frequency oscillations on EDG 2-3 was recently corrected via a retuning of the governors.

EDG reliability and unavailability numbers remained good and well within established goals.

There were no recent start failures, with the last start failure having occurred on EDG 1-1 m September 2015.

The health of DCPP's Emergency Diesel Generators (EDGs) was rated as Green (Healthy) on Unit 1 and Red (Unhealthy) on Unit 2. The Red (Unhealthy) rating was driven by a fuel oil leak that occurred during maintenance testing. The leak was repaired, and health of the Unit 2 EDGs was expected to soon return to Green. The DCISC should review the final Cause Evaluation for the leak during a future Fact-Finding Meeting. EDG reliability and availability have been good over the past two years.

Observe DCPP Plant Health Committee Meeting (Volume II, Exhibit D.2, Section 3.1; Exhibit D.4, Section 3.7; Exhibit D.5, Section 3.9; and Exhibit D.6, Section 3.8)

The DCISC has observed four Plant Health Committee (PHC) meetings during this reporting period. The PHC is governed by DCPP Procedure TS5.1D9, "Plant Health Committee," Revision 3, a copy of which was provided to and reviewed by the FFT. The PHC is a management team responsible for:

Continual review of system and program health issues 4.15-10 I

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I Routinely monitoring the status of plant health issues on the plant health issues list for action status and completion Routinely monitoring the status of the Station Top Ten equipment issues list Review and approval of action plans to address plant health issues that originated from system and component health reports, maintenance rule, operator workarounds, program health reports, and emergent issues Reviewing and approving action plans to resolve degraded, unanalyzed and non-conforming conditions Review and monitoring of plant health issue plans that are presented to the PHC Performing Preventive Maintenance Oversight Committee functions Quarterly review and monitoring of the Top Margin Issues list Approving and authorizing the PHC budget for solutions to plant health issues Approving system, component, and program long range plans The membership of the PHC Core Team, which is the Decision Making (i.e., voting) group of the PHC, is as follows:

Station Director (Chair), Engineering Director, Operations Manager, Maintenance Manager, and Nuclear Work Management Manager. The PHC is also supplemented by a group of Supporting (non-voting) Members from various other station departments.

The meetings were chaired by the Station Director and facilitated by the Program Engineering Manager. Meetings are opened by reminding the attendees that the stated purpose of the meeting was "Providing oversight and support of station reliability issues as described in System, Component and Program Health Reports and other topical initiative presentations. PHC reviews and approves critical Preventive Maintenance (PM) deferral requests."

The meetings were conducted efficiently, and the agendas were covered as scheduled. In general, the conference call format seemed to work almost as well as an in-person meeting due at least in part to the provision of detailed presentation materials in advance as well as clear and strong facilitation of the meeting. The fact that all participants knew each other personally also contributed to the meeting's effectiveness. A strong emphasis was placed on plant safety and reliability throughout the discussion.

The agenda for the meetings included the following:

Safety Review Facilitative Leadership Minute Verify Quorum Introduce Visitors and Operations Personnel Review Purpose and Desired Outcomes Action Item Review Review Pluses/Deltas and Approve Minutes from Previous Meeting What Excellence Looks Like (WELL) Assignments by week (Operations, Engineering, Security, and Maintenance)

Specific system or component issue Specific department performance review 4.15-11

Specific current system/equipment problem/solution PHC agenda requests verbal Meeting action item review Meeting Evaluation Future Agenda Requests The presentation topics were effectively performed with crisp, clear presentations and good participation and discussion by attendees.

DCPP's Plant Health Committee (PHC) meetings appeared effective in bringing together the appropriate people to address plant system and component problems and to help maintain systems and components in good health.

Reactor Coolant System Health (Volume II, Exhibit D.2, Section 3.9)

The purpose of the RCS is to transfer heat generated by the fission process in the reactor core to the secondary plant steam system as well as provide a coolant pressure boundary, serve as the second barrier against release of fission products, and promote natural circulation. The system consists of:

Reactor Vessel containing the nuclear core Pressurizer connected to the system to maintain pressure Four parallel heat transfer loops connected to the Reactor Vessel with each loop consisting of the following:

One Steam Generator which serves as a heat sink and heat exchanger to transfer heat to the secondary steam plant One Reactor Coolant Pump (RCP) which circulates the loop water Interconnecting loop piping Taps for parameter (temperature, pressure, flow) measuring instruments A basic RCS piping flow diagram is shown below:

CoalantPump Holl..

Hol'-"v Hot lag Loop4 Cold~~~

loopl Coolant Pump 4.15-12 I

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I The physical arrangement of the RCS is as follows:

Pressurizer The current health of both units' RCSs is Green (Good) with the following issues challenging system health:

Current Unit 1 Issues

1. As a result of aging concerns and to recapture operating margin, Core Exit Thermocouple (CET) replacements for one port occurred during Refueling Outage IR 17. However, due to budget constraints and higher priority work in the same field location, CET replacement activities for other CETshave not been assigned a recommended date. A bridging strategy is being implemented to perform cable health testing on all CETs and results will be utilized to prioritize CET replacements in future refueling outages.

2. Unit 1 has been experiencing elevated in-leakage into the Pressurizer Relief Tank (PRT) for multiple cycles. This has an impact on the RCS leak rate. This places a burden on Operations to drain the PRT and drain the Reactor Coolant Drain Tank (RCDT) on a more frequent basis. This has been entered into he Corrective Action Program.

3. The RCP Vibration Monitoring System has become obsolete and cannot fully retain or trend vibration data from the RCPs. Modifications were in progress to replace the systems on both units. Specifically, this modification has been implemented on Unit

1. However, Digital and Predictive Engineering have reported that there are periodic issues with the indication. As a result, implementation on Unit 2 has been deferred.

Current Unit 2 Issues I. To address the recommendations of Westinghouse Technical Bulletin TB-11-8, DCPP has decided to perform inspections of the Pressurizer Heater on (at least) a once per 4.15-13

refueling outage frequency when In-Service Inspections are performed. This includes visual inspection of the Pressurizer heater coupling weld area and sleeve. Additionally, failed heaters with identified leakage may be replaced with a welded plug instead of a new heater. A contingency design for this replacement has been issued. DCPP considers this concern to have been addressed.

2. As a result of aging concerns and to recapture operating margin, CET replacements have been approved, and 13 of 65 CETs were replaced during Refueling Outage 2R18.

A bridging strategy is being implemented to perform cable health testing on all CETs and results will be utilized to prioritize CET replacements in future refueling outages.

3. Elevated hydrogen concentration in the Unit 2 PRT has resulted in Operations performing more frequent PRT purges to keep PRT within specifications. PRT purge equipment is being cycled more than was done in previous cycles making it susceptible to failure. This issue is being tracked with the Corrective Action Program.

The DCPP Reactor Coolant System is in Green (Good) health with several minor issues which are being tracked and resolved. The system has operated reliably.

Auxiliary Feedwater Systems (Volume II, Exhibit D.3, Section 3.10)

The AFW System is a safety-related system that provides feedwater to the Steam Generators (SGs) under shutdown, startup, low power, and accident conditions. The AFW System is designed to provide a water source to the SGs in order to cool and prevent damage to the nuclear reactor fuel and to prevent overpressurization of the Reactor Coolant System in the event of transients such as a loss of normal Main Feedwater (MFW), a stuck open relief valve, or a pipe rupture on the secondary side. During normal plant shutdown, the AFW System replaces the MFW System and serves as a system to remove heat in hot standby or to cool down to a point where the Residual Heat Removal System can be placed in operation (when Reactor Coolant System temperature becomes less than 350 °F). The AFW System is also used during normal plant startup prior to placing the MFW System in service. The AFW System consists of three feed water supply trains on each unit with diverse means of powering the pumps. One train on each unit consists of a full-capacity steam turbine-driven pump, which can be aligned to use steam from any of the four SGs.

The other two supply trains consist of half-capacity electric-motor-driven pumps, each normally supplying flow to two of the four SGs, with the capability to be aligned to any of the four SGs.

The pumps normally draw water from the Condensate Storage Tank with backup supplies available from the Fire Water Storage Tank or the Raw Water Storage Reservoirs. Diesel-driven pumps from the FLEX Program are also available for use to supply AFW should the normal pumps or water supplies become unavailable during an emergency.

Both units' AFW systems were rated as Green (Healthy), with no major issues. Each unit was also rated on the following additional individual performance categories: Reliability, Maintenance Rule Compliance, Material/Equipment Condition and Corrective Actions, Operations Concerns, Performance Monitoring, and Design. All of those individual performance categories were rated as Green (Healthy) for both units.

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I Performance for the two steam-driven pumps and the four motor-driven pumps had overall been good with no recent problems. Past problems with steam-driven pump governor valve linkages had been resolved, and the station was using an electric motor to drive the steam-driven pumps during overspeed trip testing which resulted in more consistent test results. Regarding the status of corrective actions initiated following the identification of corrosion under insulation on system outdoor piping, DCPP reported that all follow-up inspections had been completed and no new corrosion concerns were identified.

The DCISC found that DCPP's Auxiliary Feedwater Systems continue to be given close attention, and the systems on both Units continue to be rated as Green (Healthy) with no major issues.

Digital Systems Update (Volume II, Exhibit D.4, Section 3.3)

The term 'digital' means that control functions have been changed from electro-mechanical analog control to digital computer control, in many cases due to obsolesce and scarcity of spare parts of older analog components. This change from electro-mechanical to computers matters because the latter have become more precise, reliable and flexible, ultimately providing a safer operating plant.

There are eight primary digital control systems at DCPP as listed below with installation dates:

1. Turbine Control System (in-service 2004)

2. Feedwater Control System (in-service 2005)

3. Process Control System (in-service 2012)

4. Two Meteorological Towers (in-service 2016)

5. Intake Travelling Screens (in-service 2017)

6. Units One and Two Spent Fuel Pool Bridge Cranes (2017-2018)

7. Unit 1 Control Room Main Annunciators (Outage 1R22) [spares to Unit 2]

8. Transient Recording System (design completed 2018)

DCPP initiated a comprehensive digital control system review in 2018 to develop a long-term strategy to assure that its digital control assets would function reliably and maintain good digital infrastructure through 2025 without facing emergent issues needing corrective action. This strategy concluded that the then-existing digital control systems would continue to perform their functions satisfactorily until the end of power operations in 2025 with no new digital systems needing to be added with one exception: the Condensate Polisher computers (programmable logic controllers) are being replaced. Additionally, the Unit 1 Control Room Main Annunciator System addition was cancelled as no longer needed. These digital system control have been successfully included in the DCPP Cyber Security Program.

• The DCPP Digital Control Systems were all reported to be in good health and have been successfully included in the DCPP Cyber Security Program.

Transmission System (Volume II, Exhibit D.5, Section 3.2) 4.15-15

Three 500kV and two 230kV transmission system connections form both a path for electricity generated by DCPP to reach system loads and a path for electricity to be supplied to one or both units when shutdown. The 230kV system is DCPP's primary source of offsite electrical power, in the event normal power is not available from one of the station's main generators. DCPP's 230kV system is served by PG&E's offsite 230kV system through two incoming lines to the DCPP switchyard. The 230kV system then connects to DCPP's vital buses through the station's Startup Transformers. Any of the station's three 500kV offsite power lines can also serve as a backup offsite power source if needed due to a 230kV outage. The station's Emergency Diesel Generators (EDGs) serve as backup if the 230kV and 500kV systems are both unable to perform their functions.

In general, DCPP considered their transmission systems to be in very good health. The system health report status was as follows:

Unit 1 Unit 1 's 500kV Transmission System was classified as Green (Healthy) with the following issues challenging system health:

Open Phase Protection - The installation of systems to automatically detect and respond to a potential open-phase condition that could affect safety-related equipment had been completed.

However, concerns with reliability of the automatic trip functions led to a planned modification to permanently disable the automatic trip functions and rely instead upon operator action. This modification was approved by the NRC and planned to be implemented during Refueling Outage 1R23 in the spring of 2022.

Line High Voltage Issues ( discussed below).

Broken Turbine Building Dead-end Insulator - A dead-end insulator on Unit 1, B Phase, was found to have its outer shell broken. Mr. Vo reviewed the basis for continued operability with the FFT and reported that both the ability to support the line and adequate insulating capability were being maintained until repairs could be made during an upcoming outage.

Unit 2 Unit 2's 500kV Transmission System was classified as Green (Healthy) with the following issues challenging system health:

Open Phase Protection - Similar to Unit 1 above, the installation of systems to automatically detect and respond to a potential open-phase condition that could affect safety-related equipment had been completed. The planned modification to permanently disable the automatic trip functions and rely instead upon operator action was approved by the NRC and was completed during Refueling Outage 2R22 in the spring of 2021.

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I Line High Voltage Issues (discussed below).

Tower 5/6 Insulator Hairline Crnck - Aerial inspection of the tie line identified a crack on an insulator at Tower 5/6. Mr. Vo reviewed the basis for continued operability with the FFT and reported that both the ability to support the line and adequate insulating capability were being maintained until repairs could be completed. Additionally, a second insulator was present at this location for support should the first insulator fail.

Unit 2 Main Bank Transformer C Undersized Fan Motor Contactors - Reviews identified that the contactors for the fan motors on this transformer were sized for 2.0 Horsepower (HP) rather than 2.5 HP as designed. Initially, replacements were considered, but a review of operating data indicated that there were no thermal anomalies and engineering recommended accepting the current configuration as adequate for continued operation.

Transformer Aging - The health of all major transformers was routinely being monitored via online Dissolved Gas Analyzers and semi-annual oil sampling. The Unit 2 Main Bank Transformer B contained the highest values of dissolved gas, but the trend was stable with no deviations of concern from historic data.

Regarding the health of the 230kV systems at DCPP, overall health was good. The 230kV system had also been recently affected by voltage issues (low in the morning and high in the afternoon),

and the Grid Control Center had been successful in taking actions to restore voltage to within acceptable limits. DCPP was also working on revising calculations to extend the times allowed for responding to such situations on the 230kV system. Additionally, there was one 230kV switch with a degraded linkage, and the linkage was planned for repair during Refueling Outage 1 R23 in the spring of 2022.

Regarding any impacts to the plant from the PG&E Public Safety Power Shutoff (PSPS) Program, it is a program being implemented by PG&E to deenergize certain transmission and distribution system power lines during weather situations where they pose a significant fire hazard risk to the general public. PSPS Program procedure B-40, "Operations Response to Wildfires," Revision 4, governed how the station responded to both PSPS events and any nearby wildfires that might threaten power lines in the vicinity of DCPP. The procedure appeared to have been appropriately focused on ensuring that the station remained aware of all offsite events and activities affecting the nearby transmission system and could respond if needed in a timely manner. Additionally, DCPP had not recently been called upon to reduce its output as a part of any load-following activities.

The health of transmission systems at DCPP was good with minor problems being tracked for resolution. Transmission systems connected to DCPP recently experienced excessive voltage issues caused by large amounts of renewable generation being added to the system in the last few years. It appeared that PG&E was appropriately managing these issues.

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Direct Current Power Systems (DCPS) (Volume II, Exhibit D.7, Section 3.14)

The DCPS is a 125 Volt Direct Current (VDC) and 250 VDC system designed to provide power for operation and control of equipment during all modes of plant operation. The system is powered by batteries that are kept charged with dedicated battery chargers. The DCPS consists of two subsystems, which are isolated from each other:

Vital 125 VDC (safety-related)

Non-vital 125/250 VDC (non-safety related)

The Vital DCPS is redundant with three separate trains per unit. Though physically separate, the trains can be manually cross connected. The system is capable of providing emergency DC power from the vital batteries for a minimum of two hours during a design basis accident coincident with a loss of on-site power, off-site power, or battery chargers. The emergency DC power is also converted to provide a small amount of emergency AC power through inverters.

The DCPS on both units were rated as "Green" or "Healthy," with no major issues. The only minor issue, which affected only the Non-vital Batteries on both units, was the presence of some hairline cracks on the lids caused by expansion of the internal plates. The cracks did not affect the structural integrity of the case and were being monitored to ensure they did not move into the sides of the battery cases. (DCPP's Vital Batteries had more room for plate expansion and are not as susceptible to the phenomenon.) A previous issue on a Vital Battery cell trending low in voltage had been resolved through cell replacement (Battery 2-2, Cell 37). The DCISC toured the DCPS equipment on Unit 1 and found all observed equipment to be in good condition.

Most DCPP vital batteries had been replaced within the last 11 years and were designed for a life of 20 years. Non-vital batteries ranged from 7 to 14 years old. It was currently believed that no batteries would require replacement prior to the cessation of power operations, but it was unclear at this time if the Vital Batteries would need to remain operational following final shutdown. Each Vital Battery receives a full discharge test during each Refueling Outage ( every 18-24 months).

The Vital Battery Chargers (five per unit) were replaced in 2004 and were considered to have a 40-year life. The Vital Inverters (four per unit) were replaced in 1994 and were also considered to have a 40-year life. Both chargers and inverters did not historically have many operating issues, and vendor/parts availability remained good.

The health of DCPP's Direct Current Power Systems on both units was rated as Green (Healthy). The System Engineer appeared knowledgeable and proactive about his system.

Containment Spray System (Volume II, Exhibit D.9, Section 3.6)

The CS System sprays water into Containment from near the top of the dome for the following purposes:

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I To remove heat from the Containment atmosphere following a Loss of Coolant Accident (LOCA) or Main Steam Line Break accident To remove fission product aerosols from the Containment atmosphere following a LOCA To deliver sufficient sodium hydroxide solution to reduce Containment sump pH and ensure that radioactive iodine remains in water-soluble form following a LOCA The CS system is a safety-related system consisting of the following components for each unit:

Two full capacity CS Pumps One Spray Sodium Hydroxide Additive Tank Spray Ring Headers and Nozzles inside upper Containment Piping and valves interconnecting the above equipment The CS Pumps take initial suction from the Refueling Water Storage Tank (RWST). The pumps start and associated valves actuate on a Containment high-pressure signal, and the system sprays water mixed with additive into the Containment atmosphere following an accident to remove heat and prevent Containment overpressure. When the R WST is empty, the CS System shuts down and the plant uses the Residual Heat Removal pumps to recirculate water from the Containment Sump into the spray headers.

Both units' CS Systems were rated as Green (Healthy) across all functions, and there were no issues affecting system health or being tracked in the reports for resolution or future improvements.

Maintenance Rule Program unavailability and reliability goals were being met with significant margins. There were no Maintenance Rule Functional Failures within the last two years. CS Pump performance remained good and only minor leaks were identified on valves within the CS System.

The DCPP Containment Spray Systems' health was Green (Healthy), and there were no significant system issues. The system's Strategic Engineer appeared knowledgeable and proactive about the system.

4.15.3 Conclusions and Recommendations

==

Conclusions:==

DCPP has dealt effectively with equipment and system problems and is focused on improving system health. DCPP's Plant Health Committee effectively focused on system/component health, and overall system health bas improved.

Recommendations: None 4.15-19

4.16 Steam Generator Performance 4.16.1 Overview and Previous Activities Steam Generator (SG) tube reliability is important to operational safety because the SG tubes are part of the Reactor Coolant System (RCS) boundary. The nuclear industry has experienced substantial problems with a variety of mechanisms that can cause the SG tubes to deteriorate. The most notable of these is stress corrosion cracking. To address these issues DCPP engaged in a major capital project of replacing all 8 DCPP steam generators: four in Unit 2 were replaced during refueling outage 2R14 (February - April 2008), and four in Unit l were replaced during refueling outage 1 R 15, (January -April 2009).

The DCISC reviewed the following DCPP Steam Generator items during the previous reporting period:

Steam Generator Inspection Frequency Steam Generator Inspection Results The DCISC concluded the following during the previous reporting period:

The DCPP Steam Generators (SGs) have been performing well since their replacements in 2008 and 2009. The most important SG parameter, tube integrity, has been shown to meet all criteria as a result of regular Eddy Current Test inspections, and very few tubes needed to be plugged. SG secondary side inspections have generally found very little foreign debris and only small amounts of sludge have been removed during cleanings. An evaluation has been initiated to extend the Unit 1 secondary side inspection and cleaning intervals from three to six cycles, which the DCISC has found acceptable.

4.16.2 Current Period Activities The DCISC did not review Steam Generators during the current reporting period; however, performance to date has been good, and no problems have been reported.

4.16.3 Conclusions and Recommendations

==

Conclusions:==

Although the DCISC did not review DCPP Steam Generators during this reporting period, the DCPP Steam Generators (SGs) have been performing well since their replacements in 2008 and 2009, and no problems have been reported.

Recommendations: None 4.16-1 I

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I 4.17 Outage Management 4.17.1 Overview and Previous Activities The DCISC monitors DCPP's outage plans, actions, and results in the following ways:

Reviews of outage safety evaluations and plans Regular fact-finding meetings to discuss planned major modifications, inspections, maintenance and activities Regular reports from PG&E at DCISC Public Meetings on outage plans and outage performance, noting any special situations or problems affecting safety Visits to DCPP during outages to monitor the Outage Coordination Center, Control Room, and activities of interest Reviews of documentation and reports of outage activities such as steam generator tube inspections, major equipment problems, and events affecting safety Since the DCISC began its review of this subject in 1990, outage management performance has steadily improved. DCPP continues to actively manage and track Outage Duration, Collective Radiation Exposure, and Personnel Safety incurred during the conduct of Unit Refueling Outages, as shown below:

Collective Outage Radiation Duration Exposure (days)

(rem)

Outage Unit 1 Unit 2 Unit 1 Unit 2 Rl3 41 39 116 74 R14 30 69 1 103 226 Rl5 5gt 38 247 87 R16 42 36 123 30 R17 552 482 41 25 R18 32 32 30 30 R19 35 32 56 29 R20 683 39 48 24 R21 37 874 30 22 R22 30 525 27 11 R23 29 18 1 Steam Generator Replacement

') - Process Control System Replacement Personnel Safety (recordable injuries)

Unit 1 Unit 2 5

3 6

3 3

0 1

0 1

0 0

0 0

0 0

0 2

1 0

1 1

3 Reactor Vessel Baffle Bolt Inspection and Replacement 4 Main Generator Stator Rebuild 5 Main Generator Stator Repairs 4.17-1

During the previous reporting period, the DCISC reviewed the following topics related to Outage Management at four Fact-finding Meetings and two Public Meetings:

Refueling Outage 1 R22 Unit 2 Forced Outages Refueling Outage 2R22 The DCISC concluded the following during the'previous reporting period:

The remotely held Outage Training to prepare Licensed and Non-Licensed Operators for Refueling Outage 1R22 and subsequent start-up and operation appeared satisfactory. The DCPP Refueling Outage 1R22 Outage Safety Plan and Safety Schedule appeared comprehensive and effective to prevent the plant safety level from dropping below acceptable safety standards. DCPP's performance in accomplishing planned work and achieving its goals was good during Refueling Outage 1R22.

A Unit 2 Forced Outage in July 2020 (2Y22) was properly managed, and corrective actions to identify and repair a hydrogen leak in the Main Generator were appropriate.

Two Outage Coordination Center meetings were conducted by conference call and effectively facilitated with crisp and clear informational exchanges across a large number of planned work activities.

DCPP appropriately managed a second and third Unit 2 Forced Outage (2Z22 and 2G22) which were driven by similar hydrogen leaks and vibration issues on the Main Generator.

Ultimately, the unit was removed from service for additional modifications during a fourth Forced Outage (2H22) and Refueling Outage 2R22. The DCISC planned to review the final Root Cause Evaluation for the problem when finalized.

4.17.2 Current Period Activities

(

During the current period, the DCISC reviewed Outage Management at four Fact-finding Meetings and one Public Meeting. The following topics were reviewed:

Refueling Outage 2R22 and 1 R23 Safety Plans Observe Refueling Outage 1 R23 Outage Control Center Activities Refueling Outage 1 R23 Results and Plans for Refueling Outage 2R23 Refueling Outage 2R22 and 1 R23 Safety Plans (Volume II, Exhibit D. l, Section 3.11, and Exhibit D.7, Section 3.1)

The purpose of an Outage Safety Plan was to provide information on outage safety requirements and highlight risk areas to plant staff. In order to assess outage safety impact, referral to the Outage Safety Plan and Outage Safety Schedule would be made prior to making major schedule changes. The intent of the Outage Safety Plan was to provide a concise document for use in evaluating plant conditions during Modes 5 (Cold Shutdown) and 6 (Refueling) to ensure the key safety functions are satisfied.

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I The Outage Safety Plan provided background information for the logic contained in the Outage Safety Checklists. The Outage Safety Checklists were governed by Administrative Procedure AD8.DC55, **outage Safety Schedule,'* a copy of which was provided to and reviewed by the DCISC. The Plan, Schedule and Checklists together ensured that the equipment and plant conditions assumed in the abnormal procedures for use during shutdown were met. The abnormal procedures contained guidance for providing passive core cooling as well as guidance on key safety system restoration. Outage safety planning was based upon being able to cope with a very severe event, which was assumed to be a loss of all AC power. Backup decay heat removal capability can be maintained during such events by assuring that the system remains capable of taking advantage of natural physical laws (natural circulation by gravity or boiling) to maintain passive cooling if Residual Heat Removal or Spent Fuel Pool cooling is lost. The Outage Safety Checklists were the primary means of verifying that normal and backup decay heat removal capabilities were maintained.

The Refueling Outages 2R22 and l R23 Safety Plans contained the following topics:

Infrequently Performed Tests or Evolutions Contingency Strategies Approved Outage Safety Checklist Exceptions Transition Periods and Testing Background Information for Outage Safety Checklists for the Following Modes:

o Mode 5 (Cold Shutdown) Loops Filled o

Mode 5 Loops Not Filled o

Mode 6 (Refueling) Reactor Coolant System (RCS) Level at Greater than l l l feet o

Core Offloaded The Outage Safety Checklists w.ere provided for each of the four basic plant outage configurations listed and described above. The Checklists were completed by Control Room Operators at least once during each shift, any time a piece of equipment was removed from service, and any time the plant entered or exited a transition period.

DCPP also used "*Phoenix,'* a computer-based tool that can be used online to analyze changes in risk using the PRA model when equipment was removed from service for maintenance. As the PRA model does not extend to shutdown conditions, Phoenix was used during outages via the loading of deterministic fault trees for shutdown conditions based on the Outage Safety Checklists. An "N+ l" Defense in Depth (DID) approach, where N generally represents the minimum equipment needed to maintain a key safety function, was then utilized by Phoenix to evaluate the maintenance of the key safety functions. This DID Status is represented by the following four color definitions:

4.17-3

Green - represents DID greater than N+ 1, where N is the minimum equipment needed to maintain a key safety function with more than one backup means of support.

Yellow - represents DID equals N+l, which is considered the normal DID.

Key safety functions are fully supported with at least one backup means of support.

Orange - represents a.DID equals N condition, where key safety functions are supported, but the normal desired DID is not met, and compensatory measures must be put in place.

Red - represents a DID less than N condition in which key safety functions are not supported.

DCPP considered a status of Green or Yellow as acceptable for planned outage activities because key safety functions are fully supported with at least N+ 1 DID. DCPP avoided planned activities which resulted in Orange conditions; however, in the rare case where an Orange condition was necessary, a contingency plan with compensatory actions must be developed, approved, and implemented. The contingency plan then provided an additional approach to DID, because it provided a backup safety function if the minimum safety function becomes unavailable. Planned Red conditions were prohibited.

Refueling Outage 2R22 was originally scheduled to be conducted from March 14 to April 16, 2021. Following shutdown of Unit 2 to facilitate Main Generator repairs in early February 2021, the start of the outage was advanced to February 23 and the outage then ended on April 17, 2021. The DCISC was provided with and reviewed copies of the Refueling Outage 2R22 Safety Plan and Safety Schedule. The Refueling Outage 2R22 Safety Plan at the start of the outage contained no Orange or Red conditions and three individual Yellow ones. The three planned individual Yellow conditions, which were fully detailed and explained in the safety plan, were as follows:

Shutdown Cooling - Remained Green.

Reactor Coolant System Inventory Control - Remained Green.

Reactivity Control - Remained Green Support Systems (Heat Sink) - One Yellow condition was planned to occur when the Auxiliary Saltwater System/Component Cooling Water System (CCW) 2-2 train was out of service at lowered inventory.

Containment Closure - Remained Green.

Vital AC Power - Two Yellow conditions were planned to occur due to a single offsite power source available when the plant was at lowered inventory while the Main Bank power supply was being removed from service at the start of the outage and later when the Start-up Bank power supply was removed from service late in the outage.

Spent Fuel Cooling - Remained Green.

The DCISC was also provided with and reviewed copies of the Refueling Outage 1 R23 Safety Plan and Safety Schedule and reviewed their purposes. The Refueling Outage 1 R23 4.17-4 I

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I Safety Plan at the start of the outage contained no Orange or Red conditions and six individual Yellow ones. The six planned individual Yellow conditions, which were detailed and explained in the safety plan, were as follows:

Shutdown Cooling - Remained Green.

RCS Inventory Control - One Yellow condition was planned to occur when only one Safety Injection (SI) Pump would be operable with fuel in the core.

(All three Centrifugal Charging Pumps out of service for testing and one SI pump out of service due to a planned maintenance outage of the 'F' Vital Electrical Bus.)

Reactivity Control - One Yellow condition was planned to occur for the same reason and coincident with the above Yellow condition for RCS Inventory Control.

Support Systems (Heat Sink) - Two Yellow conditions were planned to occur when one of two Auxiliary Saltwater System/Component Cooling Water System (CCW) trains would be out of service during lowered RCS inventory.

Containment Closure - Remained Green.

Vital AC Power - Two Yellow conditions were planned to occur due to a single offsite power source available. The first would occur when the plant was at lowered inventory while the Main Bank power supply was being removed from service at the start of the outage, and the second would occur when the Start-up Bank power supply was removed from service during lowered inventory late in the outage.

Spent Fuel Cooling - Remained Green.

The outage managers also noted that there would be no mid-loop operations required as there were no planned activities that would drain the RCS hot legs. (Mid-loop operations refer to periods during an outage when the RCS is partially drained to facilitate maintenance activities, typically on Steam Generators or Reactor Coolant Pumps. During these periods there can be reduced reactor cooling safety margins that typically require special advance planning.) The DCISC also discussed with the outage managers how unplanned schedule changes that might occur during the outage would be reviewed. The managers referred to the process and form contained in the controlling procedure which required a review to ensure that any unexpected schedule changes did not reduce the DID or affect any configurations covered by the checklists.

The Refueling Outages 2R22 and 1R23 Safety Plans and Safety Schedules appeared comprehensive and effective to maintain an appropriate safety margin during planned outage activities.

Observe Refueling Outage I R23 Outage Control Center Activities (Volume II, Exhibit D.8, Section 3.7)

The DCISC observed the 1600 Outage Control Center (OCC) Schedule Review which was a meeting convened at 4:00 pm each afternoon during outages for the purpose ofreviewing 4.17-5

changes to the detailed schedule for Unit 1 Refueling Outage 1 R23 that was in progress at the time. Items covered included the following:

Safety Update Plant Update/Defense-in-Depth Functional Area Report-Outs Emerging Issues Update Non-Outage Unit Update Outage Status Around-the-Room Discussion Wrap-up The meeting was facilitated by the Shift Outage Director, and joined by the approximately 15 persons located in the OCC.

Personnel represented Operations, Engineering, Maintenance, Radiation Protection, Chemistry, and Schedule Control. The meeting used the comprehensive and detailed outage schedule which contained all planned outage activities displayed in a linked bar-chart format.

Craft Operations and Maintenance personnel attending the meeting updated OCC personnel as to which work activities on the schedule were completed and which items on the schedule required changes due to delays to or advancement of the work activities. The DCISC observed that the discussions were very effectively facilitated with crisp and clear informational exchanges across many planned work activities by many individuals. The DCISC also observed the afternoon OCC shift turnover as well as the 12-hour shift turnover, both of which were effectively completed.

DCPP's Outage Control Center was effectively controlling Refueling Outage 1R23.

Refueling Outage 1R23 Results and Plans for Refueling Outage 2R23 (Volume II, Exhibit D.9, Section 3.11, and Volume II, Exhibit 8.9)

Refueling Outage 1R23 began on March 27, 2022 and ended on April 25, 2022. All planned work was completed with no scope deletions. Notable work activities completed during the outage included the following:

Reactor Refueling Reactor Coolant Pump 1-3 Oil Leak Repair Maintenance on Approximately 30 Primary Systems Valves Special Lifting Device In-Service Inspections Refueling Upender Spring Replacement Auxiliary Saltwater Pump 1-1 Replacement Traveling Screen Overhauls Turbine High Pressure Stop Valve Inspection F eedwater Heater Extent of Condition Inspections Vital 480-Volt Bus F Maintenance Startup Transformer Power Factor Testing 4.17-6 I

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I Significant emergent work included the following:

Reactor Coolant System Valve 1-8702 Repair Reactor Coolant System Valve LCV-495 Repair Activities that DCPP believed went well included the following:

Vital 480-Volt Bus F Maintenance Primary Systems Valve Maintenance Management of Test Schedules and Execution Performance of Mode 3 Leak Checks The biggest challenge during the outage occurred in the area of industrial safety with the occurrence of one recordable injury in the Radiation Protection Department. There were no major issues with the identification or transmission of the COVID-19 among outage workers.

There were challenges iri obtaining the desired number of supplemental employees to work during the outage, but these were addressed by rescheduling or reallocating resources.

Refueling Outage l R23 performance versus goals was as follows:

Performance Measure Serious Injury or Fatality Events Nuclear Safety Issues Site Human Perfonnance Clock Resets Outage Duration (Days)

ALARA (Person-Rem)

Power Ascension (Days)

Reliability (Days following outage)

Goal a_

0 0

< 30

< 21.3

<5

> 90 Actual 0

0 0

29.2 18.3

~7

~ l The last two goals were not achieved due to the occurrence of a secondary side problem shortly after plant startup and synchronization of the Main Generator (which defines the end of the Refueling Outage). The secondary side problem involved the failure of a pressure control valve and the subsequent lifting of a relief valve on the Steam Generator Blowdown Flash Tank. The problem required taking the Main Generator back offline in order to isolate steam and cool down secondary side systems to facilitate repairs. During the repairs, the Reactor remained online at low power with heat being removed by Auxiliary Feedwater and steam venting to the atmosphere.

This offline period was designated as Forced Outage 1X24 and lasted approximately one week.

The following is a summary of DCPP's presentation on this topic at DCISC's June 2022 Public Meeting: The twenty third Refueling Outage (l R23) for Unit 1 began on March 26, 2022 at 9:00 p.m. and ended on April 22, 2022 at 10:14 a.m. with the closure of the Unit l output breaker. Successes achieved during the outage were:

4.17-7

No nuclear safety challenges.

No industrial safety significant injury or fatality.

No foreign material challenges.

No clearance tagging challenges.

No station level events.

Lowest dose ever achieved.

The major scope activities for Refueling Outage I R23 on the primary, secondary sides of the plant and electrical work included:

Primary Drain-down primary for work on 30-40 valves.

Reactor coolant system spray isolation valve enhanced repack to address a leak.

Refueling cavity up-ender kick-off spring replaced.

Special Lifting Device I 0-year in-service inspection.

Reactor coolant pump 1-3 repair of a small oil leak.

Weld repair in Reactor Coolant System valve stem leak-off line to pressurizer relief tank.

Auxiliary saltwater pump 1-1 pump replacement.

Travelling screen 1-3, 1-4, and 1-5 overhauls.

Turbine stop valve refurbishment.

Root cause evaluation extent of condition feed water heater eddy current testing and tube plugging.

Main and auxiliary bank maintenance outage window.

Startup bank maintenance outage window.

Main Generator inspection.

Vital bus F maintenance outage window.

DCPP reported that goals and the activities established and planned for the upcoming Refueling Outage 2R23, scheduled to begin on October 16, 2022, were as follows:

Performance Measure Significant Injuries or Fatalities Nuclear Safety Events Site Clock Resets Outage Duration ALARA (person rem)

Significant FME Events Power Ascension Reliability Goal 0

0 0

S35 days TBD 0

S5 days 290 days Refueling Outage I R23 major scope activities on the primary, secondary sides of the plant and electrical work included:

Primary valve maintenance outage window.

Special Lifting Device I 0-Year in-service inspection.

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Residual heat removal pump motor overhaul.

Air test of Containment spray nozzles.

Accumulator nozzle inspections.

Main condenser expansion joint replacement and inspection.

Main feedwater pump 2-1 ruptured disc replacement.

Feedwater heater extent of condition inspection, repair and preventive tube plugging.

Turbine stop valve and turbine governor valve inspections.

Main steam isolation valve inspection.

Auxiliary saltwater pump 2-2 motor and pump replacement.

Condensate polisher computer replacement project.

Travelling screen 2-1 and 2-6 overhaul.

Main Generator inspection.

Main feedwater pump 2-2 pump inspection.

Circulating water pump 2-2 motor overhaul.

Main and auxiliary bank and startup bank.

Auxiliary transformers 2-1 and 2-2 isophase bushing inspections.

Startup transformer 2-2 power factor testing.

Vital bus F maintenance outage window.

4kV bus E aux feeder breaker racking overhaul.

12kV and 4kV bus E preventive maintenance.

Non-Vital bus maintenance.

DCPP's Refueling Outage 1R23 was successfully performed. All planned scope of work was completed, and performance goals were met except for post-outage power ascension and reliability.

4.17.3 Conclusions and Recommendations

==

Conclusions:==

The DCPP Refueling Outages 2R22 and 1R23 Outage Safety Plans and Safety Schedules appeared comprehensive and effective to prevent the plant safety level from dropping below acceptable safety standards. DCPP's Outage Control Center was observed to, be effectively managing Refueling Outage 1R23 activities.

DCPP's Refueling Outage 1R23 was successfully performed. All planned scope of work was completed, and performance goals were met except for post-outage power ascension and reliability.

Recommendations: None 4.17-9

4.18 Plant Sc

. y-Security Interface (Note: because,.

.*he sensitive nature of nuclear plant security, only limited information can be presented in thi,

,,blic report.)

4.18.1 Overvie., and Previous Activities The DCl:<C has previously reviewed plant security in fact-finding meetings by reviewing security perform,*:ice measures and by reviewing plant audits and NRC inspections of the Security Program. Additi,mally, there have been overviews of the Security Program in DCISC public meetings.

The DCISC reviews and NRC inspects these measures. The DCISC monitors and assesses current security measures and expected modifications to determine whether there may be negative effects on plant safety during normal operation and maintenance and emergency response during off-normal conditions.

The DCISC"s interest and scope of review was limited to the effects of Security.:.related barriers and procedures on nuclear and operational safety rather than Security itself. The DCISC reviewed the following DCPP safety-security interface during the previous period:

Cybersecurity Program Safety Security Interface and Intake Structure Devitalization The DCISC concluded in the previous reporting period that the DCPP Safety/Security Interface Program appeared to be implemented effectively, and the devitalization of security in the DCPP Intake Structure was based on appropriate measures.

4.18.2 Current Period Activities The DCISC reviewed the following the DCPP safety/security-related items during the current period:

Cyber Security Program Cybersecurity Program (Volume II, Exhibit D.3, Section 3.9)

The core elements of the Cybersecurity Program include identifying and implementing protection for all of the Critical Digital Assets (CDAs) at DCPP.

CDAs are digital computer and communications systems and components associated with safety-related and important-to-safety functions, security functions, emergency preparedness functions, and support systems which if compromised could adversely impact any of those functions.

During the program's initial implementation, DCPP identified approximately 4,000 CDAs across 66 critical systems. Slightly less than half of the 4,000 were in security-related systems, and the remainder were plant-related systems. Some examples of CDAs were the Programmable Logic Controllers in the Digital 4.18-1 I

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I Electrohydraulic Turbine Control System, Operator Human-Machine Interface Computers, the Plant Process Control System, Security Cameras, and the Security Event and Monitoring System.

Almost all of the CD As were located inside protected or vital areas of the plant. The CD As were evaluated, and approximately 900 were modified to assure compliance with the regulations.

Modifications included such work as locking USB ports, removing unnecessary programs, upgrading firmware, and reassigning or locking Internet Protocol (IP) addresses. DCPP completed its original implementation of the full Cybersecurity Program prior to the NRC-required due date of December 31, 2017.

An NRC inspection, conducted in late February and early March 2021, was an inspection of DCPP's program with regards to full implementation of the program to meet all updated regulatory requirements. DCPP was one of the last nuclear facilities to receive this inspection that was being performed as a new baseline inspection activity at all nuclear power plants. As such, the inspection was very thorough and included many lessons learned from other nuclear power plants. Although the details of the inspection report were considered security-related information and not available to the DCISC, it was reported that DCPP completed the NRC inspection with no findings by the inspectors, which was considered exceptional performance.

The Cybersecurity program in general was now considered mature and the station was focusing on maintaining effective implementation. One recent gap and focus area being addressed involved improvements to speed up the process for testing and implementing software patches for equipment under the program. Additional resources were being allocated to ensure that patches were tested and implemented in a timely manner.

DCPP expected that significant portions of the program would remain active at least through the first 15 months of decommissioning (the period during which the risk of a spent fuel zirconium fire remained). DCPP had reviewed recent cybersecurity incidents that received high levels of public attention (e.g., Colonial Pipeline, Solar Winds, Blackberry, etc.). and concluded that it was not vulnerable to similar attacks. The primary basis for this conclusion was the strong isolation between the corporate-wide information technology network and operating equipment at DCPP.

For example, the Colonial Pipeline attack involved emails received on plant operating computers (CDAs), and DCPP did not allow any email software or external internet connections on plant operating computers.

4.18.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's Cyber Security Program appears_ to be effectively managed, and efforts are continuing to ensure that the program is successfully sustained.

Recommendations: None 4.18-2

4.19 Independent Spent Fuel Storage Installation (ISFSI) 4.19.1 Overview and Previous Activities This section of the report describes DCISC reviews of the DCPP Independent Spent Fuel Storage Installation (ISFSI). The history of spent fuel storage at DCPP has dictated a number of changes to its approach to this matter over the years. During plant construction, the expectation for the management of used nuclear fuel was that it would be stored for a short period on site, then sent off-site to be reprocessed and reused. Accordingly, the DCPP's expectation was that there would only be the need for storing a modest amount of used fuel on site at any time, and the Spent Fuel Pools were each arranged to accommodate 270 fuel assemblies.

As time passed, the reprocessing option did not materialize because of a change in -national policy, and the impact of the accompanying uncertainty regarding the increasing used fuel inventory on site, in tum, led to the need to expand the used fuel storage capacities to 1,324 assemblies in each pool. However, national policy on this topic later became directed at the development of a national used fuel storage facility at Yucca Mountain, Nevada, which was mandated to begin receiving spent fuel in 1998. Recognizing that DCPP would indeed be able to have its used fuel shipped offsite, PG&E returned the Spent Fuel Pools again to their original capacities of 270 assemblies in each pool.

In the ensuing years, the recognition that the future of Yucca Mountain as a repository for used nuclear fuel was in jeopardy and that the future of off-site storage of used nuclear fuel was uncertain, DCPP again expanded its used nuclear fuel storage capacity to 1,324 assemblies for each pool, which are their current capacities. Also, a separate Independent Spent Fuel Storage Installation (ISFSI) was constructed on site for the dry storage of used fuel, and the ISFSI began receiving used fuel in 2009.

The DCISC reviewed the following ISFSI-related topics at two Fact-finding Meetings and one Public Meeting during the previous period:

Spent Fuel Cask Procurement Update Independent Spent Fuel Storage Installation Update The DCISC concluded the following during the previous reporting period:

DCPP's procurement of new Spent Fuel storage casks was making steady progress towards execution of a contract in early 2022. Cask procurement proposals were being evaluated and appeared to be capable of supporting movement of all Spent Fuel from the Spent Fuel Pools to the Independent Spent Fuel Storage Installation within four years of the termination of power operations for each unit. There were no active or planned campaigns to move spent fuel from the Spent Fuel Pool to the ISFSI until the new casks arrived.

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I 4.19.2 Current Period Activities During the current period, the DCISC reviewed the ISFSI at five Fact-finding Meetings and three Public Meetings. The following topics were reviewed:

Independent Spent Fuel Storage Installation Cask Inspections and License Renewal Application New Independent Spent Fuel Storage Installation Cask System Independent Spent Fuel Storage Installation Cask Inspections and License Renewal Application (Volume II, Exhibit 0.4, Section 3.2; Exhibit 0.6, Section 3.3; Exhibit 0.7, Section 3.3; Exhibit B.6; and Exhibit B.9)

DCPP submitted its NRC ISFSI License Renewal Application (LRA) on March 9, 2022. As part of that renewal process, DCPP performed a pre-application visual inspection of the external surfaces of eight stainless steel Multi-Purpose Canisters in June 2021. Additionally, the internal and external surfaces of the concrete and steel overpacks for the same eight canisters were inspected along with soil sampling and concrete pad inspections in the area.

The DCISC reviewed draft results for the inspections which concluded that the "*inspection results demonstrated that the ISFSI is in overall good condition and continues to perform its safety intended functions." Later, the DCISC reviewed the final results of the pre-application inspection which were contained in Appendix E of the LRA. The inspection concluded that the ISFSI was in good overall condition and continued to perform its intended safety functions.

All defects found during the pre-application inspection were entered into the Corrective Action Program, reviewed, and determined to be within the expected parameters under existing ISFSI aging guidance documents. The inspection results were consistent with the aging effects discussed in the LRA and the aging management actions and frequencies contained in the Aging Management Plan (AMP).

The DCISC reviewed the LRA following its submission to the NRC. The LRA requested renewal of the existing ISFSI site-specific license granted under IO CFR 72 which would otherwise expire in March 2024. The LRA requested renewal of the license for an additional 40 years beyond the current expiration date. The format and content of the LRA was aligned with NRC guidelines and included the inclusion of an AMP for the facility and associated equipment. The,LRA was organized as follows:

Section Number 1

2 3

Topic Facility General Information Scoping -

Reviews of all ISFSI Systems, Structures and Components (SSCs) for Aging Management applicability.

Aging Management Reviews - Reviews of all applicable ISFSI SSCs to determine the aging effects that could affect the ability of the SSC to perform its intended function.

4.19-2

4 Appendices Time-Limited Aging Analyses - Reviews to ensure that all applicable ISFSI SSCs will remain capable of performing their intended function through the end of the 40-year license extension period.

A. Aging Management Programs B. Previously Granted Exemptions C. Proposed License Changes D. Updated Final Safety Analysis Report Changes E. Pre-Application Inspection Report F. Environmental Report Supplement G. Decommissioning Funding In general, the Aging Management Reviews in Section 3 of the LRA identified seven SSCs that were determined to be within the scope of performing aging analyses and developing AMPs. The seven SSCs identified within the scope of the AMP were:

l. Spent Fuel Assemblies

2. Multi-Purpose Canisters

3. Transfer Cask (Holtec HI-TRAC 125)

4. Cask Overpack (Holtec HI-STORM 100)

5. Cask Transportation System

6. ISFSI Storage Pads

7. Cask Transfer Facility For each of the above SSCs, the subcomponents of the SSC subject to aging were identified and analyzed to determine possible aging effects and mechanisms. Then, the actions necessary to

• ensure the aging effects and mechanisms would not affect the ability of the SSCs/subcomponents to perform their intended function were identified and organized to form the AMP. An AMP was prepared and included in Appendix A for each of the SSCs listed above.

For example, listed subcomponents of the MPC included the shell bottom (LRA, Table 2-3, page 2-6). For the shell bottom, cracking was identified as an aging effect, and Stress Cracking Corrosion along with pitting and crevice corrosion were identified as possible aging mechanisms (LRA, Table 3-3, page 3-27). Accordingly, actions were included in the AMP for the MPC to address these mechanisms via visual screening inspections of 100% of accessible MPC surfaces for a sample number of MPCs selected according to guidance from the Electric Power Research Institute.

Defects found during visual examinations would be further analyzed by supplemental volumetric and/or surface examinations as needed in accordance with the applicable American Society of Mechanical Engineers codes. Inspections would be performed at least every five years, and inspection results that did not meet applicable acceptance criteria would be addressed as conditions adverse to quality under the CAP and ISFSI Quality Assurance Program (LRA, Table A-2, pages A-7 to A-10).

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I The following is a summary of DCPP"s presentation on this topic at the DCISC's February 2022 Public Meeting: PG&E confirmed the licensing renewal activities for the ISFSI and the new dry cask storage system required separate and distinct applications. PG&E expected each application to take approximately two years and the net result should be that the ISFSI and its spent fuel storage systems will each be licensed for a 40-year period and the two licenses will coincide in a termination date sometime in the 2060s. The ISFSI was initially licensed for 20 years but the licensing period has since been modified to allow for a 40-year extension.

PG&E was pursuing a robust, concurrent, regulatory strategy to obtain government approvals.

An overview of the strategy was outlined in a chart for the Diablo Canyon Decommissioning Planning Path which was available to the public online showing the concurrent paths with the various licensing and permitting agencies, the activities being conducted, the milestones achieved, activities completed, and the current status of decommissioriing activities. All regulatory and licensing activities were on time or early and approximately 50% have been completed with the submissions of applications. A key milestone was achieved with budgetary approval by the California Public Utilities Commission.

PG&E's ultimate goal was to eventually transport the spent fuel to a federal repository while continuing to recover costs for customers through the litigation against the U.S. Department of Energy based on the commitment by the federal government to accept spent fuel.

The following is a summary of DCPP's presentation on this topic at the DCISC's June 2022 Public Meeting: PG&E reported DCPP has since 2004 held a site-specific license for its ISFSI which has an initial term of 20 years. The ISFSI is licensed for the storage of high bum-up fuel and was sized and licensed to accommodate all fuel for 40 years of operation. The spent fuel storage system presently in use at the ISFSI is the Holtec HI-STORM 100 System with a site-specific seismic anchorage feature. To date, DCPP had completed seven spent fuel loading campaigns with 58 casks loaded with 32 fuel assemblies within each cask.

DCPP submitted its License Renewal Application (LRA) for the ISFSI to the NRC in March 2022 in accordance with the requirements of l O CFR Part 72. The NRC will review the LRA using NUREG -1927, which is the standard review plan to ensure adequacy of the application in accordance with NUREG-2214, which addresses the requirements for Managing the Aging Process in Storage. There was also industry from the Nuclear Energy Institute (NEI), NEI 14-03, --Guidance for Aging Management of Dry Cask Storage." PG&E previously received a similar ISFSI license renewal approval for its Humboldt Bay Power Plant.

DCPP first determined what parts of the system were within the scope and required review regarding aging management using two criteria. Criterion I was based upon a system or component that is important to maintaining a safety function during normal and abnormal conditions. Criterion II was based upon a system or component if it were to fail could prevent the safety function of a Criterion I system or component. Once a component or system was identified to be within the scope, its subcomponents were also reviewed. For the LRA, PG&E proposed six different Aging Management Programs (AMP) as follows:

High Bumup Fuel AMP Multipurpose Canister AMP 4.19-4

Transfer Cask AMP Overpack AMP Reinforced Concrete Structures AMP Cask Transportation AMP Each of the AMPs contained ten elements including:

Scope of the Program Preventive Actions Parameters Monitored or Inspected Detection of Aging Effects Monitoring and Trending Acceptance Criteria Corrective Actions Confirmation Process Administrative Controls Operating Experience Using this process, the NRC would be able to use its standard review plan to confirm the different elements of the AMP have been addressed and the intended function of all systems and components in the AMP will be maintained based on the periodicity of the inspections that will be performed for each of the six AMPs.

OCPP reported that the LRA submitted in March 2022 was expected to have a determination for sufficiency or acceptance review by July 2022, and the NRC's goal, subject to staffing and resource levels, was to have the review completed within three years The inspections for stress corrosion cracking of DCPP Independent Spent Fuel Storage Installation stainless steel multi-purpose canisters and overpacks were completed with no significant adverse findings. DCPP was appropriately managing the license renewal process including the development of an Aging Management Plan for the Independent Spent Fuel Storage Installation (ISFSI).

New Independent Spent Fuel Storage Installation Cask System (Volume II, Exhibit 0.8, Section 3._10; Exhibit 0.9, Section 3.2; Exhibit B.3; and Exhibit 8.9)

DCPP's existing Independent Spent Fuel Storage Installation (ISFSI) dry storage system utilizes Holtec as the vendor and uses a system of vertical stainless steel Multi-Purpose Canisters (MPCs) and concrete and steel Overpacks for the storage of spent fuel assemblies.

Each MPC holds 32 spent fuel assemblies, and there are 58 MPCs stored in Overpacks at the ISFSI. In early 2021, PG&E began the process of soliciting proposals for the supply of a new spent fuel storage system and associated services.

The following is a summary of OCPP"s presentation on this topic at OCISC's October 2021 Public Meeting: PG&E presented a slide showing the timeline for the dry cask storage Requests for Proposals for a modified or new dry cask storage system. PG&E was still in 4.19-5 I

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I active negotiations with multiple proposers and therefore detailed information could not be released until a decision was made and which was expected during the first quarter of 2022.

Concerning the request for proposals, public input was received, a study was commissioned and conducted by UCLA, input was received from the Diablo Canyon Decommissioning Engagement Panel, and from the NRC and the California Energy Commission conducted a separate technical review. The procurement time for the current casks was expected to be approximately 18 months. There were no plans at present to conduct a spent fuel loading campaign prior to the cessation of operations, and there was adequate space within the spent fuel pools for the remainder of operations. Overall, PG&E's goal was to complete the off-loading all spent fuel by 2029, four years after cessation of operation.

Based upon an assumption of 32 assemblies per cask, offloading would require loading approximately 80 casks in two years. In prior loading campaigns, DCPP averaged loading one cask every six days. The establishment of a non-qualified trust for additional revenues was an important aspect of the schedule because under existing NRC regulations, DCPP could not access funds for. physical work until 45-60 days after cessation of operations. With the non-qualified trust, governed by the state, funds were available earlier and contracts could be entered into for work outside the narrow window provided by NRC regulation. This contributed to greatly reducing the project schedule and the risk. Funds to be collected in 2022-2023 would be adequate to cover the entire cost of the dry cask storage system and manufacturing of that system could begin prior to cessation of operations.

The following is a summary of DCPP's presentation on this topic at the DCISC's February 2022 Public Meeting: Concerning the proposals for a new dry cask storage system for spent fuel, PG&E reported the time for issuing the purchase order was drawing very near and was expected by the end of March 2022. PG&E stated that the dry cask storage system represented the ultimate critical path for decommissioning DCPP and as such will be subject to the most public scrutiny. No civilian nuclear facility had previously loaded as many casks as DCPP would endeavor to do after cessation of electrical generation operations, and the spent fuel pools would be close to capacity at the time of commencement of that effort. The contract for the new spent fuel storage system represented a very significant financial commitment for PG&E and the process had been meticulously managed. With PG&E's commitment to offload the spent fuel pools within four years of cessation of operations, cask loading activities were not anticipated to commence until 2027-2028. Once a contract was awarded, the license application would be prepared and the NRC public process on licensing would commence concurrently with the California Public Utilities Commission review in the 2021 NDCTP for cost and budget approval. All prospective vendors were required to submit designs that could be accommodated within the dimensions of the existing ISFSI due to the ISFSI's location on the same geologic formation as the power block and the similar seismic analyses for the two facilities. The only exception would be for storage of greater than Class C radiological waste which was not contemplated when the ISFSI was designed. A pad for storing greater than Class C waste was planned to be constructed in the vicinity of the facility presently storing the old steam generators.

In March 2022, PG&E selected a new vendor for future the movement and storage of additional spent fuel assemblies at the ISFSI. Orano was selected as the new vendor, and they would provide PG&E both equipment and contractor services for the future movement and storage of 4.19-6

spent fuel assemblies. PG&E considered that the primary advantage of the proposed Orano Spent Fuel Storage System was in the simplification of the interface between the plant and the ISFSI. Specifically, spent fuel canisters would move directly from the transporter to storage and would not need to be handled or repackaged into overpacks using the ISFSI Cask Transfer Facility. Additionally, the Orano system could support the movement of all spent fuel from the plant to the ISFSI on a much shorter timeframe than could be accomplished using the previous system. It was estimated that the Orano system could support the transfer of all spent fuel from the spent fuel pools to the ISFSI within two years following the cessation of operations (assuming timely NRC approval of the system, including proposed enhanced thermal capabilities). PG&E also believed that the Orano system would achieve many of the desired attributes received via the public input from the Diablo Canyon Decommissioning Engagement Panel (reducing the time required to transfer all spent fuel to the ISFSI, access to perform inspections, retrievability, etc.). Use of the Orano system and timeframe would also prevent spent fuel activities from interfering with decommissioning activities, and the use of a

'spent fuel island' approach to separate the Spent Fuel Pool area from the rest of the station would not be required.

The Orano system was already licensed by NRC and in use at 17 nuclear power plants in the U.S. and others overseas. The Orano system would employ their NUHOMS Extended Optimized Storage (EOS) system, a modular horizontal storage system. In the NUHOMS system, spent fuel would be loaded under water vertically into a Dry Shielded Canister (DSC),

each of which would hold 37 spent fuel assemblies. After loading, the DSCs would be dried via vacuum drying, filled with helium, and moved to the horizontal position for transfer to the ISFSI via specialized transporter. Once at the ISFSI, the DSC would be inserted directly from the transporter into a Horizontal Storage Module (HSM). Each HSM would be a reinforced-concrete and structural steel enclosure approximately 25 feet long and 20 feet tall. The HSMs would be bolted together into groups (arrays) at the ISFSI pad to enhance their ability to withstand seismic loads without tipping over.

The Orano staff explained the licensing process for the new system to the DCISC. Currently, DCPP" s use of the Holtec system was covered by a site-specific NRC license under 10 CFR Part 72. The proposed new Orano system is currently licensed by the NRC for general use (at multiple facilities) under 10 CFR Part 72 (the NRC regulations governing spent fuel storage).

PG&E planned to use the Orano general license for the new system, which would be allowed via a change to PG&E"s facility license under IO CFR Part 50 (the NRC regulations governing power reactors). It was envisioned that in the end, DCPP would have a mix of casks licensed under a site-specific license (Holtec) and casks licensed under a general license (Orano) at the ISFSI, which is currently also the case at four other nuclear power plants in the U.S.

There was one major licensing change that would be required to support the proposed use of the Orano DSCs at DCPP. It was planned to request that the NRC approve a modification to the general license that would allow the use of maximum heat loads up to 50 kW total and 4.2 kW per cell (assembly). The DCISC asked what the impact would be should such an approval not be received, and the Orano staff explained that the currently approved (lower) maximum heat load for the DSC could be used, but a longer time (approximately 30 months after shutdown, 7 months longer than the allowed by the current plan) would be required to complete 4.19-7 I

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I the movements of all fuel assemblies to the ISFSI. The DCISC inquired regarding what would be done with the currently installed seismic anchors for the MPCs at the ISFSI, and the Orano staff responded that the anchor rings would be removed. The pad would then be restored to a flat surface prior to the installation of the HS Ms, as the HS Ms would not need to be anchored to the ISFSI pad.

The following is a summary of DCPP"s presentation on this topic at the DCISC's June 2022 Public Meeting: PG&E reported that the CPUC in the 2015 Nuclear Decommissioning Cost Triennial Proceeding (NDCTP) mandated that PG&E review the transfer of spent fuel within seven years, akin to the schedule achieved by the San Onofre Nuclear Generating Station in Southern California. Later in the 2018 NDCTP, a settlement was reached which required the transfer of spent nuclear fuel was to be achieved within four years. With responses to the Request for Proposals (RFP), the successful proposer and all other proposers provided for a transfer period of 23 months. PG&E's RFP was informed by the Strategic Vision document and the independent technical expertise as well as an expert advisory panel of consultants to challenge the licensing approach and the selection of a vendor.

In early 2022, PG&E announced its selection of the Orano system as new supplier, which would result in switching the configuration of spent fuel storage from vertical [Holtec] to horizontal [Orano]. Licensing documents to update the current license Orano will use for DCPP were planned for submission by the end of 2022. Fabrication of the system was scheduled for 2023 to 2025, and the schedule forecasted completing the unloading the Unit l Spent Fuel Pool first before moving to Unit 2.

Key reasons for PG&E's choice of the Orano system included the performance and design of the system, its simplicity, and its horizontal configuration. All fuel will be stored at the ISFSI and the 58 Holtec casks now on the site will remain along with the new Orano concrete horizontal storage modules. With the Orano system, it will no longer be necessary to use the Cask Transfer Facility. A number of other nuclear power plants have both site-specific

[Holtec] and general [Orano] licenses. Moving forward, Orano would continue to provide information and the California Energy Commission was going to continue to review the technical specifications. Along with the DCISC, PG&E will continue to maintain its internal safety and technical advisory committee, all of which will provide different perspectives.

A representative from Orano described the components of the NUHOMS EOS spent fuel storage system including its horizontal storage modules (HSMs) and the dry storage canisters (DSCs), which were transported within a transfer cask loaded from within the spent fuel pool, to be stored horizontally within the HS Ms. The use of horizontal storage lowers the center of gravity of the DSC which provided for more seismic stability. Having the multiple HSMs in proximity to each other also aided in self-shielding and lowered the dose rate. The DSCs to be used at DCPP will have 3 7 compartments to hold 3 7 spent fuel assemblies. It was planned that 69 HS Ms would be required to complete the offload at DCPP.

DCPP's process for selection of a new Independent Spent Fuel Storage Installation system by Orano appeared appropriate. The new Orano system had been licensed by NRC and was in use at 17 U.S. nuclear power plants. The DCISC should continue to review technical information on the new system and its NRC licensing documents as more information becomes available.

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4.19.3 Conclusions and Recommendation I

==

Conclusions:==

The inspections for stress corrosion cracking of DCPP Independent Spent 1

Fuel Storage Installation stainless steel multi-purpose canisters and overpacks were completed with no significant adverse findings. DCPP was appropriately managing the license renewal process and the development of an Aging Management Plan for the Independent Spent Fuel Storage Installation and its existing spent fuel storage system.

I DCPP's process for procurement of a new spent fuel storage system by Orano appeared 1

appropriate. The DCISC planned to continue to review technical information on the new system and its NRC licensing documents as more information becomes available.

Recommendation: None.

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I 4.20 Earthquakes and Tsunamis 4.20.1 Overview and Previous Activities This section of the report provides updates on recent seismic events, tsunamis or related matters that could affect DCPP.

In previous reports the DCISC has reviewed with PG&E earthquakes occurring in California in the vicinity ofDCPP as well as seismic designs, analyses, and activities related to DCPP. This has included updates to PG&E's Long Term Seismic Program which is an NRC license condition requiring PG&E to monitor and evaluate seismic events world-wide which could potentially affect DCPP design.

The DCISC reviewed the following during the previous reporting period:

Workplace Seismic Safety In the previous reporting period, the DCISC concluded that DCPP's evaluation of the effects of an earthquake on the Control Room Procedures Cart, concluding that it would noy cause damage to Control Room, appeared satisfactory.

4.20.2 Current Period Activities The DCISC reviewed the following items during the current period:

Lessons Learned from Texas Extreme Weather Event Workplace Seismic Safety Lessons Learned from Texas Extreme Weather Event (Volume II, Exhibit D.l, Section 3.5)

DCPP reported on an industry Operating Experience (OE) notice entitled, '*Rapid OE, Severe Weather program - Extreme Cold;* and DCPP's plant specific analysis of the information contained in the OE notice. The OE notice summarized the problems that occurred at a nuclear plant in Texas and elsewhere due to freezing of inadequately protected instrumentation lines primarily on the main feedwater pumps which ultimately caused a reactor trip. The weaknesses identified by the OE included the fact that the severe weather programs at those stations did not include an adequate assessment of equipment vulnerable to extreme conditions. DCPP's review of the OE concluded that the plant was not vulnerable to similar problems due to 1) similar instrumentation at DCPP being located inside an enclosed turbine building and 2) DCPP being located in a very mild environment.

Design information contained in DCPP"s Updated Final Safety Analysis Report (UFSAR) included a review of ten years of actual weather data at DCPP which concluded that the most extreme cold weather that was forecasted to occur at DCPP was 39°F. DCPP performed extensive studies of ambient temperature effects on unconditioned switchgear rooms during 2014 and 4.20-1

-l

containment cooling in 2020 and did not find any ambient conditions approaching that low-temperature design basis.

DCPP collected many ambient weather data points through its plant data systems, and its meteorological tower in particular. The historical DCPP meteorological tower data for ambient temperature from February 2017 to July 2021. The data showed a high temperature of 96.5°F and a low temperature of 42.5°F at the DCPP site over the last four years with no discernable long-term trends for extreme temperatures.

DCPP adequately reviewed the February 2021 Texas nuclear power plant extreme cold weather event for applicability to DCPP, and no additional actions were necessary.

Workplace Seismic Safety (Volume II, Exhibit D.8, Section 3.8)

The FFT received and reviewed DCPP's **standards for Bracing Office Furniture, Cabinets, and Storage Racks Revision 2 (1/30/2020). This document defines when and how to brace office furniture, file cabinets, bookcases, and storage racks. The policy is intended to protect personnel from injury and ensure egress routes are not blocked by office furniture impact. These standards appeared satisfactory.

The DCISC toured the Instrumentation and Electrical Facility to review workplace seismic safety conditions. The facility appeared to meet all applicable DCPP standards.

DCPP's Workplace Seismic Safety program appeared satisfactory and appeared to be properly implemented judging from a DCISC Fact-finding Team tour of the Instrumentation and Electrical Facility.

4.20.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's evaluation of the effects of an earthquake on workplace personnel safety and their evaluation of the applicability low temperature Texas event were satisfactory.

Recommendations: None 4.20-2 I

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I 4.21 Fire Protection 4.21.1 Overview and Previous Activities Fire protection requirements are contained in NRC s regulations in 10 CFR 50.48 and 10 CFR 50 Appendix R.

These regulations specify the minimum requirements for safe shutdown systems and equipment, fire hazards analysis, prevention, detection and mitigation, fire brigades and training, emergency lighting, fire barrier and penetration qualifications, and fire doors. PG&E has committed to implementing these requirements, utilizing interpretations and deviations approved by NRC. NRC regulations were later modified to allow licensees to substitute a probabilistic-risk based program under National Fire Protection Association standard NFP A-805 for the requirements of Appendix R, and DCPP modified its program to align with NFPA-805. The NRC periodically performs inspections of the DCPP fire protection program implementation.

The DCISC reviewed the following ISFSI-related topics at three Fact-finding Meetings during the previous period:

Fire Protection and Detection Systems Fire Protection Program - NFPA-805 Update Wildfire Risk The DCISC concluded the following during the previous reporting period:

Over the last few years, an increased level of attention to the health of DCPP's Fire Protection and Detection Systems has improved system performance, and the number of impairments has been significantly reduced. This is excellent performance and a notable contribution to improving overall safety at DCPP. The DCPP National Fire Protection Association-805 Fire Protection Program and the Fire Department itself both appeared satisfactory based on periodic exercises and audits and inspections by regulatory organizations. Wildfire risk at DCPP has been reviewed extensively, and DCPP has fire prevention and mitigation plans to maintain fire lines and manage vegetation such that the risk of wildfire damage to the plant was low.

4.21.2 Current Period Activities During the current period, the DCISC reviewed Fire Protection at one Fact-finding Meeting. The following topic was reviewed:

Fire Doors and Door Life Management Fire Doors and Door Life Management (Volume II, Exhibit D.6, Section 3.7)

DCPP has approximately the following numbers of doors in the Power Block:

4.21-1

967 total ECG Equipment Control Guideline* (ECG) and Non-ECG doors 414 ECG doors, including 280 fire, 83 HVAC (ventilation system), 26 HELB (high energy line break), and four combination flood and fire doors 148 doors with security functions

• Equipment Control Guidelines are similar to Technical Specifications in that they specify requirements for items, although ECGs do not require NRC approval for changes.

When the DCISC began looking at fire doors in 2013, it concluded the following that funding deferrals were inappropriately limiting door repairs and replacements. The DCISC"s concern was that, regardless of funding deferrals, the delayed fire door correction schedule was unacceptable, and DCPP moved quickly to improve their timeliness. The impact of corporate overhead on the cost of fire door replacement was listed as one of several components of the high cost of door replacement in that there had been a change in corporate cost allocation at DCPP which increased the replacement cost.

After a slow start on repairing or replacing impaired doors, a new "Power Block Door Project" was presented on. July 15, 2014, to the Project Review Committee for funding. This Project included replacement of 94 doors in the Power Block because they had outlived their useful life, i.e., they had degraded to the point where they could no longer be repaired without difficulty to meet the design safety function. Later, in 2016, DCPP decided to repair as many doors as possible. The Project Review Committee approved this request, including approval of the 2015 Power Block Project scope in the DCPP Five Year Plan and funding for an additional four years in the future. At that time, the DCISC concluded that DCPP was making good progress with its impaired fire doors.

In 2019, there were 27 impaired doors being worked. (Door impairments include problematic hinges, handles, skin failures, locks, closers, etc. Such impairments typically result from normal use as plant doors typically experience tens of thousands of openings and closings per year.) Six of the impairments were on fire doors, which were getting highest priority. The last of the impaired fire doors was scheduled to be replaced or repaired by early May 2019. Since then, the following numbers of impaired doors were replaced or repaired:

In 2020 out of 15 impaired doors, 12 were replaced and 3 repaired.

In 2021 out of 16 impaired doors, 12 were replaced, three were repaired, and one was carried over to 2022.

In 2022 there are five impaired doors, which will be repaired or replaced soon The DCISC found that DCPP's Door Life Management Program was intact and healthy.

Personnel appeared to be on top of any door impairments, especially fire doors and others, which were needed for safety-related purposes, such as High Energy Line Break protection of vital equipment. The Fix-It-Now Team was assigned the job of identifying and repairing/replacing any impaired doors and seemed to have an adequate level of resources to assure repairs/replacements were performed quickly and efficiently.

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I DCPP's fire door repair program continued to be strong and effective in repairing or replacing impaired fire and other safety-related doors in a reasonable timeframe.

4.21.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's fire door repair program was strong and effective in repairing or replacing impaired fire (and other similar safety-related) doors in a reasonable timeframe.

Recommendations: None 4.21-3

4.22 Learning and Development Programs 4.22.1 Overview and Previous Activities The focus of this section is training performed in formal environments created to transfer specific knowledge and skills to individuals within the organization for their individual development.

The DCISC reviewed the following Leaming and Development Programs topics at two Fact-finding Meetings during the previous reporting period:

Control Room Simulator Leaming Services Department Update The DCISC concluded the following during the previous reporting period:

DCPP's Control Room Simulator was performing well in supporting operator training and examinations. The simulator was being properly certified and updated, and simulator reliability was high.

Learning Services Department overall performance was good, and the Department was appropriately focused on ensuring that staff remaining on site through the cessation of power operations were adequately qualified.

4.22.2 Current Period Activities During the current period, the DCISC reviewed Leaming and Development Programs at three Fact-finding Meetings. The following topics were reviewed:

Observe Licensed Operator Classroom Training Observe Licensed Operator Simulator Training Leaming Services Department Performance Observe Licensed Operator Classroom Training (Volume II, Exhibit D.4, Section 3.1)

Operations consists of five shifts of Licensed Control Room Operators and Non-licensed Plant Operators. Each shift of Licensed Operators undergoes training every fifth week when the plant is not in an outage. This training consists of classroom and simulator training. The DCISC observed a classroom training session centered on the following Emergency Operating Procedures for loss of **normal" heat sink, i.e., reactor core cooling during normal operation versus loss of**ultimate" heat sink, which is emergency Auxiliary Saltwater System cooling from the Pacific Ocean:

EOP FR-H. l, Response to Loss of Secondary Heat Sink EOP FR-H.2, Response to Steam Generator Overpressurization EOP FR-H.3, Response to Steam Generator High Level 4.22-1 I

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I EOP FR-H.4, Response to Loss of Normal Steam Release Capabilities EOP FR-H.5, Response to Steam Generator Low Level The lesson was based on these procedures and the bases behind the procedure steps, which were provided in the student reference binder and were discussed throughout the lesson.

The instructor challenged the students with questions about this sequence of events. The students were knowledgeable and participative.

Based on observation of a class on the use of emergency procedures for dealing with a loss of heat sink, the DCISC Fact-finding Team observed that the instructor was knowledgeable about the subject and displayed good techniques in both providing information and in eliciting student participation, and that the quality of materials was high.

Observe Licensed Operator Simulator Training (Volume II, Exhibit D.4, Section 3.8, and Exhibit D.5, Section 3.7)

The DCISC observed a November 17, 2021, operator simulator training session on Anticipated Transients without Scram (A TWS ). An A TWS event was one of the "worst case** accidents which could only happen if the scram system (i.e., the rapid shutdown by dropping all control rods into the nuclear reactor core, which provides a highly reliable means of shutting down the reactor's chain reaction) were to fail to function when called upon during a transient event requiring shutdown. The instructor used the first part of the lesson time on the simulator floor to review the A TWS scenario and walk through the DCPP procedures on identifying and responding to ATWS. There was good participation by the students, who appeared familiar with A TWS and the procedures. The instructor was knowledgeable of the subject and effectively completed the lesson.

The DCISC observed a December 7, 2021, licensed operator simulator scenario for a crew comprised of Licensed Operators the majority of whom were currently working in off-shift positions. Most of the crew's licenses were currently inactive; meaning, they did not regularly work the minimum number of on-shift hours necessary to maintain their licenses in active status.

DCPP maintains a higher number of inactive Licensed Operators (approximately 20) than is typical in order to maintain a reserve pool of off-shift operators as the plant approaches the cessation of power operations. The DCISC considered this an excellent approach to reduce the risk of dropping below the required number of Licensed Operators due to unexpected operator losses. Inactive license holders were still required to participate fully in all training weeks. The simulator scenario was designed to evaluate crew performance in any or all areas and was not tied to any particular course of instruction.

This scenario was similar to one which would be performed during the operating portion of a formal initial license or requalification examination.

The scenario ran for approximately 90 minutes and consisted of the following events:

Nuclear Instrument N-43 fails high High vibration on Main Feed Pump 1-2; rapid power reduction to 50% required 4.22-2

Tube rupture on Steam Generator 1-2; Reactor Trip and Safety Injection initiated Safety valve fails open on Steam Generator 1-2 Safety Injection Phase A fails to automatically actuate Turbine-Driven Auxiliary Feedwater Pump 1-1 trips on overspeed, Motor-Driven Auxiliary Feedwater Pump 1-2 fails to automatically start, and Motor-Driven Auxiliary Feedwater Pump 1-3 discharge pressure transmitter fails Critical tasks were identified for each of the above events, and the crew was evaluated in their ability to complete the critical tasks including the correct usage of abnormal and emergency operating procedures as well as emergency event classification and reporting.

The DCISC observed that the crew performed well and successfully completed all critical tasks. Some inconsistences were observed in verbal communications, but this was not unexpected considering the fact that most of the crew were not regularly serving together as on-shift Operators. Followingthe simulator scenario, the DCISC observed the instructor debriefing during which minor crew deficiencies were appropriately identified and documented by the instructors. Overall, the simulator training appeared to be effectively conducted, and operators performed well during the scenario.

DCPP includes both classroom and control room simulator training on Anticipated Transients Without Scram (A TWS) as part of its Continuing Training Program for NRC-Licensed Control Room Operators, and the training appeared to be appropriate. The simulator performed as expected. A Licensed Operator Continuing Training simulator session was well prepared, contained appropriate objectives, and was professionally conducted by the Training staff. Operators performed well in responding to the simulated off-normal events. The DCISC observed a number of inactive Licensed Operators in training and considers DCPP's plan to maintain a high number of inactive Licensed Operators in off-shift positions an excellent approach to reduce the risk of dropping below the required number of Licensed Operators due to unexpected operator losses as the plant approaches the cessation of power operations.

Leaming Services Department Performance (Volume II, Exhibit D.9, Section 3.1)

The DCISC received an overview of Leaming Services Department activities for Operations training programs. In early 2021, DCPP successfully completed its last class of Initial License Training for new licensed operators with a 100% pass rate (21 of 21) on the final NRC examinations. Additionally, the department was in the process of finishing the training for a class of 11 new Non-Licensed Operators who would join the operating shifts at the end of May 2022. The DCISC team inquired about department staffing for the Operations training programs, and PG&E reported that there were 16 staff remaining in the group, down from approximately 32 a few years ago. The remaining staff were primarily responsible for Licensed and Non-Licensed Operator Continuing Training as well as the maintenance and use of the Control Room Simulator. Additionally, they would coordinate DCPP's participation in its last NRC Licensed Operator Requalification Program inspection and examination in the summer of 2023.

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I Regarding Maintenance and Technical trammg programs, PG&E reported that the programs were focused upon providing the necessary refresher training for qualified individuals in the Maintenance and Engineering Departments. There were 12 accredited maintenance craft qualification programs provided by the department. Occasionally, there were new employees reporting who needed technical training for qualification, but most new employees had experience from elsewhere in the industry. If a new employee needed a qualification requiring accredited training, a gap analysis was done for the individual to identify specific areas of training required for the individual to complete all of the requirements for their new position. Regarding training for engineers, most training was being provided as needed in response to each individual engineer's specific training plan.

Staffing in Maintenance and Technical training was currently at 14 positions, down from about 22 positions two years ago. Most of the staffing reductions were made through normal attrition and reorganizing the group to reduce the number of supervisors.

The DCISC was provided and reviewed copies of the Performance Improvement Dashboard for the department and the Leaming Services Department Excellence Plan.

Several of the gaps identified and tracked in the Dashboard were explained, which included minor issues with exam security and with tracking the attendance of Operators at Continuing Training.

The Excellence Plan appeared to be appropriately focused on supporting station focus areas as well as coordinating the transition of the department into the decommissioning timeframe.

Lastly, the DCISC inquired regarding how the department would be working to design and implement a training and certification program for Certified Fuel Handlers (CFHs), which would be needed to support decommissioning activities following the cessation of power operations. PG&E reported that the Decommissioning group would be managing the CFH training program. That group had hired a training supervisor who would be working with the Leaming Services Department to develop a CFH training and qualification program using the INPO "Systematic Approach to Training" process.

Learning Services Department overall performance was good, and the Department was appropriately focused on ensuring that staff remaining on site through the cessation of power operations will be adequately qualified.

4.22.3 Conclusions and Recommendations

==

Conclusions:==

The DCISC observed that classroom training on the use of emergency procedures for dealing with a loss of heat sink was well conducted by an instructor who was knowledgeable about the subject and displayed good instruction techniques.

Two Licensed Operator Continuing Training simulator session were observed, and the simulator performed as expected.

Simulator training activities were well prepared, contained appropriate objectives, and were professionally conducted by the instructors. Operators performed well in responding to simulated off-normal events.

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I 4.23 Beyond Design Basis Events 4.23.1 Overview and Previous Activities.

The purpose of the section is to describe the DCISC's review of "Beyond design basis events," such as occurred at the Japanese Fukushima Daiichi nuclear plant in March 2011. During the previous period, the DCISC did not review any Beyond Design Basis items because there were no new or unreviewed DCPP items.

In the previous reporting period the DCISC concluded that, although the it did not review any DCPP Beyond Design Basis items during the current reporting period, it has found DCPP;s program acceptable in the past.

4.23.2 Current Period Activities During the current period, the DCISC reviewed the following Beyond Design Basis items:

FLEX Program Update FLEX Program Update (Volume II, Exhibit D.8, Section 3.2)

FLEX is not an acronym but describes a strategy developed by the nuclear industry to provide diverse and flexible coping strategies to address the loss of safety-related systems due to beyond design basis events. Prior to the Fukushima accident in 2011, DCPP had portable generators and other equipment to respond to beyond design basis events, under the post-9/11 terrorist event "B.5.b" orders from the NRC. Following the Fukushima accident, the FLEX Program was initiated to procure additional (mostly portable) components to mitigate various beyond design basis events such as occurred at Fukushima. These events include loss of all station power; loss of the ultimate heat sink; natural events such as earthquakes, tsunamis, and local intense precipitation; and fires or explosions, which could render installed equipment ineffective. FLEX equipment includes, among other equipment, portable diesel-driven pumps and electric generators along with any necessary associated plant connections, piping, controls and instrumentation.

DCPP reported that its FLEX equipment is not considered safety-related because it is designed not to the plant design basis, but to commercial grade quality requirements, which means the FLEX equipment is not subject to Federal Regulations contained in 1 0CFR50, the Nuclear Regulatory Commission's safety-related regulations. DCPP does not currently take credit for FLEX equipment in its safety analyses.

DCPP built a special enclosed facility to store its FLEX equipment as well as storing some of it outside ( e.g., trailers, trucks, tractors, and piping) with proper coverings. FLEX equipment is tested, maintained, and replaced by DCPP personnel on a schedule tailored specifically to the type of equipment (e.g., batteries, pumps, generators, etc.).

DCPP maintains a FLEX Equipment Status Board, which is a spreadsheet or table listing each of the 65 pieces of equipment along with the following:

4.23-1

Equipment Name/Type Status (all pieces of equipment were "Operational and In Position or "Green")

Corrective Action Program (CAP) Notification Number (none at the time of this meeting)

Physical Location Unique Equipment Designation (ID)

In addition to the above spreadsheet, the DCPP Program Owner developed another spreadsheet with the following:

Equipment Name Equipment ID DCPP Department Responsible for Maintenance and Testing Past and Future Maintenance Schedule Past and Future Test Schedule CAP Notifications for Corrective Actions such as procedure revisions, software updates, missing labels, peeling paint, etc. There was nothing major in this category.

4.23.3 Conclusions and Recommendations

==

Conclusions:==

The DCPP FLEX Program was healthy thanks to tight controls on equipment status, maintenance, testing, and needed corrective actions. All FLEX equipment was in the status of "Operational and In Position."

Recommendations: None 4.23-2 I

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I 4.24 Joint Proposal and Decommissioning 4.24.1 Overview and Previous Activities On June 21, 2016, PG&E announced a Joint Proposal with Friends of the Earth, the Natural Resources Defense Council, Environment California, the International Brotherhood of Electrical Works Local 1245, Coalition of California Utility Employees, and the Alliance for Nuclear Responsibility to retire DCPP at the expiration of the current operating licenses. On August 11, 2016, PG&E filed an Application with the California Public Utilities Commission (CPUC) for approval of the retirement of DCPP, implementation of the Joint Proposal, and for recovery of associated costs through proposed ratemaking. Under the Joint Proposal, PG&E would continue to operateDCPP at current levels through the current license periods. The application was approved by the CPUC on January 11, 2018, affirming the plan that PG&E would retire Unit 1 in 2024 and Unit 2 in 2025.

In the previous period, the DCISC reviewed the following topics related to the Joint Proposal and Decommissioning Program at one Fact-finding Meeting and two Public Meetings:

Employee Retention Programs Decommissioning Planning Update Decommissioning Engagement Panel The DCISC concluded the following during the previous reporting period:

The DCPP Employee Retention Program was proceeding generally as planned. Most operators and instrumentation and controls technicians, who are especially needed through the end of generation, were remaining. Planning for the decommissioning of DCPP was proceeding well, and the Decommissioning Engagement Panel was serving well to represent the interests of the community and other stakeholders.

4.24.2 Current Period Activities During the current period, the DCISC reviewed the Joint Proposal and Decommissioning Program at three Fact-finding Meeting and two Public Meetings. The following topics were reviewed:

Employee Retention Programs Decommissioning Planning Update Decommissioning Engagement Panel Capital Project Planning Employee Retention Programs (Volume II, Exhibit D.3, Section 3.2; Exhibit D.5, Section 3.10; and Exhibit B.6) 4.24-1

The DCISC reviewed the overall staffing statistics for DCPP. Prior to the 2015 decision not to seek license renewal, DCPP employed about 1400 people and historic£1lly incurred a turnover of about 150 people per year. In September 2021, staffing at the site was about 1100 employees, which was approximately what was forecast to be the case at the end of the Tier 1 retention program (completed in late 2020). Originally, the station expected a sudden reduction of about 200 employees at the end of the Tier 1 retention period. The actual losses that occurred were about the same number (200), but the losses occurred more gradually over a longer time period and not mostly around the end of the retention period.

Looking forward, there were some additional losses expected to occur as the station approached the end of the first year of the Tier 2 retention period ( first retention payment paid in November 2021 ); however, based on recent trends the station no longer expected to see any sudden large loses of employees. To date in 2021, 55 employees left DCPP and 39 new employees were hired.

Regarding the impacts of recent losses, there were a few areas where personnel losses were heavier or more concentrated than desired. Areas heavily impacted by recent losses included In-Service Inspection (ISi) Engineering, Reactor Engineering, and Electrical Maintenance. The losses in the Engineering Department were very concerning to many individual employees, and the department was focusing on ensuring that any resulting gaps were being identified and appropriate actions taken. For example, the loss oflSI Engineers was being managed through the hiring of replacement contract personnel or the retraining of other engineers, and the losses in Electrical Maintenance had already been filled by newly hired employees. The DCISC was provided with and reviewed documents which illustrated how the station was closely tracking personnel counts by department. Much of the overall effort to monitor staffing numbers was being managed through the People Committee, which was a group of senior managers who meet on a weekly basis to review staffing numbers and concerns. The station was also considering the fact that the workload of many groups was decreasing as the station approached the cessation of power operations. For example, the Outage and Planning Department recently lost one of two key managers; however, that department's workload has been steadily decreasing as future outages would not require as large a scope of scheduled work ( e.g., fewer maintenance and modification activities) as the plant approaches the cessation of power operations.

Regarding the impact of turnover in leadership positions, DCPP was focusing on properly managing leadership staffing by identifying Subject Matter Experts (SMEs) who could provide backup knowledge for each new and existing leader's positions. Each leader's position had at least one and as many as three SMEs listed who could be called upon to assist a new leader if needed or provide backup leadership should a position unexpectedly become vacant. Additionally, each new leader was being provided a Job Familiarization Guide prepared by the outgoing leader or another SME.

DCPP was also regularly monitoring its Corrective Action Program for any trends that might be attributed to employee or leadership turnover, and no specific problems or issues had been identified as being caused by employee turnover., The Nuclear Safety Oversight Committee expressed concerns with leadership turnover but also acknowledged that they also could not identify any specific negative trends or issues that had occurred due to leadership turnover.

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I The DCISC was informed that the station believed it was being successful at helping employees whose positions would be eliminated after the cessation of operations become ready to move to new employment opportunities inside or outside of PG&E. PG&E"s program for retraining workers was entitled, "*Pathways to Your Future,'* and included enhanced educational support, technical training programs, and transition support programs. Many employees were already taking advantage of new educational and training opportunities that would enable them to qualify for employment elsewhere inside or outside of PG&E. New educational opportunities in which employees were showing particularly high interest included cybersecurity and project management certifications.

DCPP's Employee Retention Program included a Tier 1 four-year incentive payment period which began in 2016 and ended in 2020 and a Tier 2 three-year incentive payment period which began in 2021 and was planned to end in 2023. The DCISC reviewed staffing numbers to ascertain if any significant losses occurred around the time of the first Tier 2 retention payment which was made at the end of November 2021. It had been postulated that there could be significant losses just prior to that payment date as employees chose to resign rather than receive the payment and incur the obligation for repayment should they leave prior to the end of 2023. The DCISC found that there was not a significant increase in employee losses around the Tier 2 first payment date in November 2021.

The following is a summary of the DCISC's discussions on this topic at its February 2022 Public Meeting: Through PG&E's agreement to the Joint Proposal in 2016, the DCPP workforce was offered a 25% retention payment over their base salaries each year in order to retain critical members of the workforce needed to operate and maintain the power plant.

The Employee Retention Program provided for two tiers, with Tier 1 in place from 2016 through 2020 and Tier 2, in its second year, to remain in place from 2021 to 2023. The retention programs saw a participation rate of 95% for both tiers which was considered very successful. The numbers of DCPP plant staff had gradually been reduced through attrition to a level described as appropriate to the present time. DCPP leadership reviewed staffing adequacy for each department at weekly meetings and performed intensive reviews of workforce planning by specific departments including Operations, Engineering, and Security. During 2019, DCPP hired its largest class of non-licensed operators to prepare the participants over the required two-year training period to assume roles in the Operations Department. DCPP presently has the highest number of senior reactor operators in its employ in the industry which should serve DCPP well until 2025. DCPP Senior Vice President and Chief Nuclear Officer announced PG&E's commitment, following the end of Tier 2, that anyone who wished to continue working for PG&E following the cessation of generation operation by DCPP would have the opportunity to do so.

DCPP's Employee Retention Program was being well managed and generally proceeding as expected. The station has incurred some unplanned losses, but the resultant impacts were being appropriately managed.

Staffing numbers and employee skills contiqued to be adequate to support safe operations. The station did not incur any significant increase in staffing losses in conjunction with the disbursement of the first Tier 2 incentive payment in November 2021.

4.24-3

Decommissioning Planning Update (Volume II. Exhibit 8.3)

The following is a summary of the DCISCs discussions on this topic at its October 2021 Public Meeting:

DCPP was processing all regulatory approvals required for the decommissioning process in parallel; that is, seeking an extension for the present dry cask storage system at the same time as it is seeking a new dry cask storage system.

Simultaneously, DCPP was pursuing license amendments from the NRC to step-down licensing requirements and discretionary permits from the State of California and the County of San Luis Obispo for land use matters. The CPUC concluded its 2018 Nuclear Decommissioning Cost Triennial Proceeding (NDCTP) and in that proceeding provided full funding for the decommissioning budget. That budget informed the scope of the decommissioning effort, and the scope informed the process for obtaining the required permits and licenses. Doing all these activities in parallel was more complex, but DCPP was obtaining good results and was on or ahead of scheduled for each discretionary action.

DCPP's goal was to have all discretionary approvals in hand prior to Unit 2 ceasing operation so that it could proceed directly into decommissioning. This had been the concept since the Joint Proposal was entered into in 2016, and in this way a certain portion of the plant's workforce could be retained at a significant cost savings.

DCPP presented and discussed a slide showing the Diablo Canyon Decommissioning Path tracking and showing a timeline for the various activities in connection with decommissioning the power plant. The status of those activities was reviewed, and the finish line for all activities was forecasted to be the end of 2024. This goal was based upon extensive benchmarking and fits not only with other power plants' experience but also with the permitting and licensing windows for the original ISFSI dry cask storage system and the steam generator replacement project. The goal was to complete the project safely and efficiently, to have all fuel stored at the ISFSI, and to ultimately obtain release the 10 CFR Part 50 license from the NRC. This approach to early planning resulted in cost savings through preservation of the decommissioning trust funds, and the CPU C's approval of the amount of$3.9 billion in the 2018 NDCTP greatly reduced both project and schedule risk.

DCPP reported that the establishment of a non-qualified trust for additional revenues was an important aspect of the schedule because under existing NRC regulations DCPP could not access funds for physical work until 45-60 days after cessation of operations. With the non-qualified trust. governed by the state, funds were immediately available and contracts could be entered into for work outside the narrow window provided by NRC regulation.

This contributed to greatly reducing the project schedule and the risk. With funds to be collected in 2022-2023, there would be adequate funding to cover the entire cost of the dry cask storage system and manufacturing of that system can begin prior to cessation of operations. DCPP has what was characterized as an immense, 10 CFR Part 50 license area and work could begin during 2023 or 2024 to narrow that Part 50 license area to a more manageable area as the non-qualified trust enables PG&E and its contractors to advance the project schedule in a fashion that has not been seen before in the decommissioning of a nuclear power plant.

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I DCPP was recruiting across multi-disciplines in support of decommissioning. Starting in 2016 and running through 2024, the DCPP Decommissioning organization was ostensibly a licensing, permitting, engineering and finance organization and during that time a strong team had been developed. In the history of U.S. nuclear power plants to date, only ten facility licenses have been successfully retired and DCPP's licenses would be the eleventh.

PG&E planned to announce its decommissioning contracting strategy by the end of 2021 when it submitted its 2021 Nuclear Decommissioning Cost Triennial Proceeding to the CPUC. That filing would inform the scope of what the utility takes on and what may be transferred to another party. He reported there were five basic decommissioning models:

( 1) self-perform where the utility does everything; (2) hybrid where the utility functions as its own general contractor; (3) use of decommissioning general contractor where the utility retains a smaller workforce and oversees the decommissioning general contractor's activities; ( 4) license transfer where the utility transfers the license to a third party on a temporary basis for that party to act as custodian of all aspects under the 10 CFR Part 50 License and return the license to the utility for termination; and (5) license transfer and asset sale where the utility sells the trust fund and the plant site and facilities to a separate demolition contractor. The decision to be made as to which model PG&E will use would also inform the question of recruitment to support decommissioning.

Decommissioning Engagement Panel (Volume II, Exhibit B.6)

The following is a summary of DCPP's presentation on this topic at DCISC's February 2022 Public Meeting:

Ms. Linda Seeley reported about the Diablo Canyon Decommissioning Engagement Panel (DCDEP) on which she served as a member. The DCDEP had been in operation since 2018 and consisted of eleven members. Several members had recently changed, and the process for selecting panel members was very competitive.

DCDEP strove to be a process-oriented rather than a goal-driven organization, and its mission was to represent the community.

Ms. Seeley called the Committee's attention to the Strategic Vision Report which was updated each year to document the DCDEP's activities and decisions and the process employed in those efforts; that is, she stated not only the outcomes are documented but also how the DCDEP came to its conclusions. The DCDEP maintains a regularly updated website and all DCDEP public meetings include the opportunity for public comment and a kiosk is in place to receive comments from the public. She stated in addition to its public meetings the DCDEP holds public workshops to solicit community input but unfortunately the COVID-19 pandemic had forced the interruption of some its activities.

The DCDEP by consensus identified four requirements for inclusion in PG&E's request for proposals for a new spent fuel storage system with those requirements being 24-hour real-time radiation monitoring for each individual cask, the ability to inspect the top, bottom and sides of the casks, the ability to repair a cask, and the ability to move the casks without having to repackage its contents. The DCDEP was also concerned regarding the integrity of the storage casks presently on the site as they cannot be fully inspected, repaired or moved and also with a perceived lack of prospects for the availability in the near future 4.24-5

of a consolidated interim storage facility for nuclear waste which perception is based upon the NRCs policy of consent-based siting for such a facility.

Capital Project Planning (Volume II, Exhibit 0.9, Section 3.10)

In response to the plan for DCPP to cease power operations at the end of its current license, a Project Review Working Group (PRWG) was formed in 2017 using experienced staff from Operations, Engineering, and Work Control. The PRWG completed a review of the entire portfolio for future capital projects and made recommendations for cancellations or modifications given the reduced life of the facility. The work of the PR WG was considered complete with the acceptance of the capital project recommendations and the associated financial impacts as a part of PG&E"s 2020 General Rate Case before the California Public Utilities Commission.

For the ongoing management of capital project approvals and implementations, DCPP was using its normal process which centered around the work of the Plant Health Prioritization Committee (PHPC). The work of the PHPC was covered by procedure AD7.ID18, --Plant Health Prioritization Committee,'" Revision 3, a copy of which was requested and provided to the FFT. A simplified overview of the capital project management process was as follows:

Requesting engineer or other **issue owner" brings a Plant Health Issue Plan to the PHPC for its review. The PHPC reviews the issue and decides upon the funding of a study to investigate details on the issue and provide options for resolution.

Proposed project study returns to PHPC for review and approval to move forward with authorization of funds to proceed with development of a scope of work for the proposed project (referred to as '*Gate 1" in the procedure).

Proposed project detailed scope of work and cost returns to PHPC for review and approval to move forward with preliminary design and cost estimate ('*Gate 2"").

Proposed project preliminary design and cost estimate returns to PHPC for review and approval to move forward with detailed design and implementation

('*Gate 3").

Other PHPC reviews and gates would follow the implementation and closing of the project as needed.

Meetings of the PHPC were held on an as-needed basis depending on the level of project activities being considered and managed. DCPP provided the DCISC with a list of capital projects brought to the PHPC since 2020 which were cancelled during the PHPC review process as follows:

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I Upgrades to both units' Main Annunciator Systems - A spare parts bridging strategy was developed and approved as an adequate means to address system agmg concerns.

Upgrade to Unit 2 Reactor Coolant Pump Vibration Monitoring System - Based on the poor results of a similar project on Unit 1, the project was deemed not feasible and maintenance of the existing equipment was evaluated as adequate until the cessation of power operations.

Unit 1 Reactor Vessel Level Indication System bellows replacement - A review determined that regular preventive maintenance of the system would be adequate to ensure proper operations through the cessation of power operations.

Upgrades to plant recorders-Replacements of numerous analog recorders with digital recorders were already completed, and it was found that further analog recorder replacements were unnecessary as an adequate inventory of spares was available.

Relocations of chemistry sampling stations - It was determined that concrete modifications would be necessary for the proposed changes which would significantly increase the complexity and cost.

Instead, procedures were changed to allow the use of other existing sampling locations.

Unit 2 Spare Startup Transformer piping replacement - It was determined that preventive maintenance on the spare transformer was adequate and that piping replacement was not needed.

The DCISC also inquired about which capital projects were authorized for implementation over the previous two years, and DCPP later provided a list of authorized projects. The list showed that there was a total of 18 Capital Projects authorized since 2020, of which were seven were directly related to security. The remaining 11 non-security related Capital Projects authorized and funded for completion were:

Polar Crane Post-Modification Upgrades Emergent Outage Replacement of Nuclear Instruments Suez (Water Treatment) Facility Upgrade Condensate Polisher Computer Workstation Upgrades Capital Tools Equipment Unit 2 Condenser Expansion Joint Replacement GQD (Emergency Diesel Generator Local Alarm Panel) Plug-In Alarm Relays Replace Main Generator Stator Closed Cooling Water Manifolds Intake Gantry Crane Radio Control System Unit 2 Replace TCV-23 (Generator Hydrogen Cold Gas Temperature Control Valve) Actuator Unit 2 Replace Main Turbine High Pressure Governor Valve 4.24-7

DCPP's process for authorizing or cancelling proposed capital projects appeared effective. Selections made to delete projects using this process did not appear to compromise plant operational safety.

4.24.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's Employee Retention Program was being well managed and generally proceeding as expected. The station incurred some unplanned losses, but the resultant impacts were being appropriately managed. Staffing numbers and employee skills continued to be adequate to support safe operations.

DCPP's planning for Decommissioning was proceeding on schedule and with appropriate coordination of the regulatory filings and approvals needed to support a prompt and efficient start to decommissioning work activities shortly after the planned cessation of power operations in 2025. The DCISC continued to work with the Diablo Canyon Decommissioning Engagement Panel to identify areas where the DCISC's mission and activities could support the work of the panel.

DCPP's process for authorizing or cancelling proposed capital projects appeared effective. Selections made to delete projects using this process did not appear to compromise plant operational safety.

Recommendations: None 4.24-8 I

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I 4.25 Other DCISC Reviews 4.25.1 Overview and Previous Activities This report section includes other DCISC reviews, which do not fall into the other categories of the report. This includes meetings with plant officers and directors and reviews of the status of COVID-19 at DCPP. The DCISC reviewed the following specific topics during the previous reporting period:

COVID-19 Pandemic Planning & Response Meet with DCPP Officer or Director Drone Sightings The DCISC concluded in the previous reporting period that DCPP's response to and actions for dealing with effects arising from the COVID-19 pandemic are based on maintaining safe, reliable operations with a healthy staff. Their initiatives appeared appropriate for handling normal operations as well as potential responses to emergencies. DCPP's COVID-19 actions did not appear to adversely affect operational safety.

4.25.2 Current Period Activities During the current period, the DCISC performed the following reviews:

Meetings with DCPP Officers DCPP COVID Response and Update Meetings with DCPP Officers (Volume II, Exhibit D.l, Section 3.6; Exhibit D.2, Section 3.2; Exhibit D.3, Section 3.3; Exhibit D.4, Section 3.1 O; Exhibit D.5, Section 3.12; Exhibit D.6, Section 3.1; Exhibit D.7, Section 3.10; Exhibit D.8, Section 3.12; and Exhibit D.9, Section 3.9)

The DCISC Fact-finding Team met with a DCPP officer at each of its nine fact-finding meetings.

The items discussed were the fact-finding agenda and results to date and other items of mutual interest.

The regular meetings between DCISC Members and DCPP Officers and Directors continue to be beneficial for both organizations.

COVID Update (Volume II, Exhibit D.3, Section 3.4 and Exhibit D.6, Section 3.5)

DCPP has taken 'an active role in providing vaccinations to over 900 DCPP plant employees who requested them and to over 400. other PG&E employees in San Luis Obispo County. Following vaccinations, the number of COVID-19 cases for employees dropped; however, the number of cases recently started to trend back upward, similar to trends seen within the local community.

DCPP was continuing to be very successful in avoiding worker-to-worker transmissions of the 4.25-1

disease on site. Employees continued to be screened daily via software that required employees to answer several questions to confirm they were healthy prior to reporting to work. Recently, the software had been slightly modified to align with current state and federal guidance for vaccination status, travel restrictions, and quarantine procedures. When the screening resulted in a concern over an employee's health, the employee was referred to their supervisor and a representative from the Human Relations (HR) Department for further guidance according to a pre-determined process.

Typically, about ten employees were referred to HR for further guidance each workday by the.

screening software.

PG&E had recently reverted to requiring face masks for all employees on site, consistent with state and local guidelines. Most employees who could work from home were continuing to do so, and only limited face-to-face meetings were being conducted on site. PG&E was still reviewing the latest federal guidance regarding mandatory vaccinations.

Approximately 65% of DCPP employees were currently vaccinated with higher percentages for management and lower percentages for hourly employees. To date, the number of employee absences from the site at any one time had not reached any levels requiring significant compensatory actions.

Although DCPP had seen a recent increase in COVID (Omicron) positives, it'believes it had a lower incident rate than most domestic nuclear power plants, and that its past practices were paying off. Not having any refueling outages in 2021 has helped keep relative incident rates down. PG&E corporate had recently issued a new COVID directive on January 4, 2022 with the following points:

All coworkers who can perform hybrid work-that is, work which can be performed remotely or in the office-* shall work from home. In-person work shall only be performed if it is both deemed essential for business continuity AND not possible to do from home.

Coworkers shall only meet in person for critical business needs. Our previous in-person meeting guidance is suspended at this time.

o Critical business is work that cannot be deferred or delayed, and that is essential to maintain continuity of service to our customers, assure the safety of our co-workers and the public, or meet compliance obligations with our regulators.

In-person gatherings planned at PG&E facilities in January, such as end-of-year/holiday social gatherings, team brainstorming meetings and similar meetings at PG&E facilities are postponed. We continue to value the ability for coworkers to come together in person, and with many of our customer-facing roles it is unavoidable; however, due to the current health environment, in instances where holding in-person meetings can be avoided, it should be.

Those attending meetings in person for critical business needs must continue to follow the COVID-19 Prevention Standard established in December.

This directive appeared appropriate to the DCISC FFT for personnel protection.

DCPP continues to take a strong, proactive approach against the COVID-19 Pandemic.

There have been only a few occurrences of COVID-19 transmission on site at DCPP, and there have been no situations when a significant number of employee absences affected operations.

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4.25.3 Conclusions and Recommendations

==

Conclusions:==

DCPP's response to and actions for dealing with effects arising from the COVID-19 pandemic are based on maintaining safe, reliable operations with a healthy staff.

Their initiatives appeared appropriate for handling normal operations as well as potential responses to emergencies. DCPP's COVID-19 actions did not appear to adversely affect operational safety. The regular meetings between DCISC Members and DCPP Officers and Directors continue to be beneficial for both organizations.

Recommendations: None 4.25-3

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I 5.0 DCPP Performance DCPP operational performance is reported in Volume II; Exhibit C, "Diablo Canyon Power Plant (DCPP) Operations.'"

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6.0 DCISC Open Items List The DCISC Open Items List is a database used to track items for follow-up and monitoring.

The List is updated and reviewed at each public meeting. The Open Items List included in Exhibit Fin Volume II was used at the DCISC June 22-23, 2022 Public Meetings.

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7.0 PG&E Actions on Previous DCISC Report Recommendations The DCISC has made 224 recommendations in its previous 31 Annual Reports. The recommendations, PG&E responses and DCISC dispositions from the previous five DCISC reporting period are included in Exhibit I, Volume II, along with references to the location for the basis for each recommendation.

The DCISC had no recommendations in its 2017-2018 report.

The DCISC had no recommendations in its 2018-2019 report.

The DCISC has one recommendation in its 2019-2020 report.

The DCISC had no recommendations in its 2020-2021 report.

The DCISC has no recommendations in this (2021-2022) report.

The DCISC concludes that the actions taken by PG&E relative to past DCISC recommendations have been satisfactory and have helped to maintain or improve safety and reliability.

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I 8.0 Public Input and Outreach The DCISC has welcomed and encouraged input from the public since its inception in 1990. As part of its Public Outreach Program the Committee has established a number of channels of communication opportunities in an effort to foster public outreach. Until the onset of the COVID-19 pandemic in early 2020 these have been in the form of three public meetings each year in the local community together with plant tours at certain meetings that are open to the public. During this annual report period all public meetings were conducted in person in Avila Beach, California, in a hybrid format affording the public the opportunity to participate virtually using Zoom webinar remote meeting technology. No public tours were conducted during this annual report period and with PG&E's promised cooperation, and in consideration of any COVID-19 pandemic-related restrictions and the needs of the power plant as it proceeds into decommissioning, the Committee plans to commence offering tours to members of the public during the next (33rd) annual report period. Notice of all three public meetings was published in local newspapers and on the DCISC website and was sent by USPS or email to those persons and entities on the DCISC' s Service Mailing List ( see Volume II, Exhibit 8-10) maintained in accordance with California Government Code § 1491. A notice was sent to all such persons and entities during this Annual Report period of the opportunity to receive notice of DCISC public meetings by email. The Committee's public meetings were each webcast in real time and are available for subsequent viewing on the web through archived streaming video linked to each meeting agenda. The public meetings are subsequently broadcast on Channel 21 the local government access channel.

Each meeting during this annual report period provided access to members of the public to participate remotely by Zoom using a computer or by telephone. The Committee maintains a toll-free telephone line and a convenient link for emailing the Committee is provided on its website. The DCISC also issues public notices, press releases and advertisements for every public meeting. Input from the public has been received as described in this section.

8.1 Email Received by the DCISC Email correspondence was received by the DCISC Legal Counsel's office with questions, concerns, information and requests for information. During this reporting period one telephone call and 35 email-initiated contracts were received from members of the public and responded to by the DCISC. The breakdown of these telephone calls and emails is as follows:

Number of Telephone Calls 0

Number of Emails 18 17 Reason for Contact DCPP issues or nuclear Information or related requests Other (administrative, document requests, tour requests and miscellaneous)

When requested, answers, responses or documents from the Committee's records were provided by email or in some cases during a public meeting. The DCISC Correspondence Log which provides a memorandum of contacts initiated by members of the public, citizen or public interest groups, the 8-1

media or similar organizations is included as Exhibit G.1 and correspondence is included with Exhibit G.2.

The Committee maintains a California toll-free telephone number (800-439-4688), an email address (dcsafety@dcisc.org) and a site on the worldwide web at www.dcisc.org for receiving questions, concerns or information to and from the public. The DCISC has developed an information pamphlet and an informational video describing the Committee and its activities (see Volume II, Exhibit I).

The pamphlet is provided to attendees at DCISC public meetings and plant tours and the informational video is shown in connection with the public tours and on the Committee's website.

8.2 DCISC Internet - Worldwide Web Page Activity The DCISC maintains a frequently updated web page on the worldwide web at https://www.dcisc.org/. Since the DCISC established its web page and presence on the internet in 1999 the Committee's goal has been to provide a convenient and accessible forum for interested members of the public to learn about the Committee, its history, background and role in safety oversight at Diablo Canyon as well as its current and past members, technical consultants and legal staff. Volumes I and II of the Committee's latest and its past Annual Reports are available on the website as is the current schedule of future DCISC public meetings and plant tours and the agendas, legal notices, PG&E informational presentations and the entire agenda packet are posted to the website before each of the Committee's public meetings.

The web page also provides visitors with an opportunity to download or print pages from the DCISC website and its Annual Reports and offers a convenient email link to permit interested persons to communicate directly with the Committee and to receive an expedited response to questions and concerns. When the Annual Report is finalized it is also published and distributed as a CD to local public libraries and interested persons.

The Committee previously engaged Sun Star Media of Monterey to redesign and update the DCISC website. As part of the update a new visual interface for the website was created. The website has been redesigned to be easy to navigate and to be friendly to users of mobile phones and computer tablets as well as to be compliant with the requirements of the Americans with Disabilities Act. The website now includes a photo gallery showing the Committee during its public meetings and the members and technical consultants at work during fact finding. The website also features a video gallery with videos with information about the Committee and its activities, the Diablo Canyon used fuel storage project and used fuel management, the replacement of the steam generators, and seismic safety at Diablo Canyon. A topical library has also been created to feature information concerning the post-shutdown role for the Committee, the committee's review of decommissioning-related issues, review of seismic safety issues, the tsunami hazard and risk at Diab lo Canyon and its environs, as well as the Committee's evaluation of safety issues for alternate cooling technologies or modifications to Diablo Canyon's once-through cooling system.

The Committee continues to post the agendas and the agenda packets for all its public meetings on the website prior to its public meetings as well as general information about the Committee, its members and consultants. A section on Resources provides links to websites for the NRC, PG&E-Diablo Canyon, the California Public Utilities Commission, the International Atomic Energy Agency, the Diablo Canon Decommissioning Engagement Panel and to San Luis Obispo County's Nuclear Incidents webpage. Links are provided to indexed streaming video of its past public 8-2 I

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I meetings through electronic archives at https://slo-span.org/static/meetings-DCISC.php and to the public meetings in real time when in session.

The website also provides access to a convenient glossary of nuclear power terms and a list of acronyms in common use in the nuclear industry and an animated depiction of the operation of a pressurized water nuclear reactor such as those in operation at Diablo Canyon.

During the DCISC' s public meetings on October 19-20, 2021, the livestreaming feed of the meeting, produced by AGP Video, was accessed 15 times on October 19 and 24 times on October 20, 2021. During the February 15-16, 2022, the livestreaming feed of the meeting was accessed 22 times on February 15 and 11 times on February 16, 2022. During the DCISC public meeting on June 22-23, 2022, the livestreaming feed of the meeting was accessed 19 times on June 22 and 53 times on June 23, 2023. This data represent the total number of times **live visitors entered the site during the meeting including those visitors who may have come and gone from the site more than once.

During this annual report period www.dcisc.org was hosted by Sun Star Media. The statistics provided for July 1, 2021 through June 30, 2022 by Sun Star Media using Google Analytics which provides information on users, new users and sessions, as follows:

Month Users New Users Sessions Pageviews July 2021 116 111 137 246 August 2021 118 114 131 233 September 2021 104 99 110 224 October 2021 202 194 245 626 November 2021 135 128 143 230 December 2021 111 108 126 331 January 2022 109 106 119 211 February 2022 118 108 159 379 March 2022 196 192 207 315 April2022 114 109 139 299 May 2022 111 103 134 252 June 2022 226 214 311 735 "Users'* represent identified unique visitors to the site, "New Users'* are previously unidentified visitors, **sessions" represent unique instances of browsing the website, and "Pageviews" are the unique pages viewed.

Top ten countries from which visitors accessed the site as of June 2022 were: United States, South Korea, Germany, India, China, United Kingdom, Japan, Russia, France, Pakistan.

8.3 Comments Received at DCISC Public Meetings During this period (July 1, 2021 - June 30, 2022), the Diablo Canyon Independent Safety Committee (DCISC) held three public meetings in the vicinity of Diablo Canyon Power Plant (DCPP). These two-day public meetings included numerous informational, programmatic and plant status presentations by PG&E and by Committee Consultants and questions and comments from the 8-3

public. The Committee held an evening session on the first day of each of its public meetings during this annual report period.

The DCISC encourages members of the public to attend and speak at its public meetings. Times are set aside throughout the meetings for public questions and comments. During the reporting period July 1, 2021 - June 30, 2022, thirteen different individuals spoke a total of sixty-nine times. Nine individuals participated and spoke at the October 19-20, 2021, public meeting; nine individuals participated and spoke at the February 15-16, 2022, public meeting; and nine individuals attended participated and spoke at the June 22-23, 2022, public meeting. Eight persons addressed the Committee during more than one of its public meetings. These statistics include persons who participated and spoke in-person and those who participated and spoke remotely as part of the Zoom webinar conducted with each of the Committee's public meetings during this report period.

The comments and questions, together with the Committee's and PG&E's responses, are contained in the public meeting minutes included in Volume II, Exhibits B.3, B.6, and B.9.

8.4 DCISC Public Tours ofDCPP Due to restrictions imposed by the coronavirus pandemic, the DCISC did not conduct tours of the power plant with members of the public in conjunction with any of its public meetings during this annual report period.

8.5 DCISC Evaluation The DCISC has been successful to date in implementing its Public Outreach Program as demonstrated by the descriptions above. The DCISC will continue to review its outreach programs including concerning future public tours during the next reporting period. The usage of the website during this annual report period demonstrates the success of the effort to create an interesting format for public outreach and to provide information on the Committee and its activities as well as an email channel for communication.

Attending one or more public DCISC public meetings during this report period were representatives of the Senator Diane Feinstein's Central District Office, the County of San Luis Obispo Planning Department and the Diablo Canyon Decommissioning Engagement Panel. Also attending were representatives of the San Luis Obispo Mothers for Peace and the Alliance for Nuclear Responsibility, non-profit organizations concerned with the local and nationwide dangers involving Diablo Canyon and with the dangers of nuclear power, weapons and radioactive waste on national and global levels, and a representative of Californians for Green Nuclear Power, a group dedicated to promoting the peaceful use of safe, carbon-free nuclear power, and to keeping Diablo Canyon Nuclear Power Plant open after 2025.

The Committee Members recognize the important mandate from the California Public Utilities Commission that the Committee conduct public outreach in the local San Luis Obispo area and will continue to explore and develop opportunities for interaction between the Diablo Canyon Independent Safety Committee and the public.

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9.0 PG&E RESPONSE TO DCISC's 32nd ANNUAL REPORT

[To be incorporated into the 33rd Annual Report]

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