International Observers and Nuclear Safety at Kashiwazaki-Kariwa

Introduction

The Kashiwazaki-Kariwa Nuclear Power Station (KNPS), while currently not in operation, has taken key lessons from past events and is undergoing extensive efforts to ensure a safe and responsible restart.
Following the Fukushima Daiichi Nuclear Power Station Accident, the importance of strengthening nuclear safety became clearer than ever. The lessons learned from that event have driven significant advancements at KNPS, reinforcing a commitment to robust risk management and preparedness. As a result, KNPS has implemented extensive multi-layered safety measures based on TEPCO's "defense-in-depth" philosophy. These enhancements are designed to mitigate risks of power outages, necessity of reactor cooling and dispersion of radioactive substances caused by natural disasters such as earthquakes and tsunamis.
A key aspect of these safety advancements has been the role of third-party observations. Independent assessments by Japanese and international experts, including visits by organizations such as the Nuclear Reform Monitoring Committee (NRMC) and the International Atomic Energy Agency (IAEA), have validated KNPS's progress and reaffirmed TEPCO's commitment to transparency, accountability, and continuous improvement. TEPCO welcomes these visits as an essential component of responsible nuclear management, ensuring that the highest safety standards are upheld remains strong and acquiring public confidence in KNPS.

NRMC's Assessment and Feedback

A critical component of KNPS's safety assurance is the oversight provided by the Nuclear Reform Monitoring Committee (NRMC). NRMC is an advisory body to TEPCO Holdings' Board of Directors, established to ensure the effective implementation of nuclear reform efforts. Comprising domestic and international experts, the committee provides oversight and supervision from an external perspective. Through continuous observations and guidance, the committee plays a key role in ensuring that KNPS meets the highest safety standards.
For further details, please visit the NRMC official page

Chairman of the Nuclear Reform Monitoring Committee (NRMC) Dr. Dale Klein

"The exercise I observed today was as rigorous as we conduct in the US. The performance was excellent as well.' He added, 'Although the performance convinced me that the plant is ready to be restarted, I hope that the people of Kashiwazaki-Kariwa NPS will never be complacent and will aim for further improvements."

Chairman of the Nuclear Reform Monitoring Committee (NRMC), an advisory body to TEPCO's board of Directors, and former chairman of the U.S. Nuclear Regulatory Commission. The NRMC has been assessing the security and safety of KNPS for 13 years. In December 2024, the committee visited the station to observe a general emergency exercise and review the command system.

Chairman of the Nuclear Reform Monitoring Committee (NRMC) Dale Klein

A comprehensive review of KNPS was conducted between May 13 and May 17, 2024, by a team that included a representative from the NRMC. This detailed inspection, which focused on Unit 7 as an exemplar of the station's overall progress, concluded that KNPS has made significant advancements in safety and operational readiness. The findings reaffirmed that no critical issues were identified, reinforcing confidence in the station's preparedness.

Key Findings from the NRMC Report*1:

  • Sound Preparations:
    • Field inspections, equipment checks, and open interviews with station personnel and upper management confirmed that all aspects of restart readiness were being addressed. The report noted exemplary maintenance, spotless housekeeping, and an overall healthy safety culture. Minor issues, such as small taped-sign discrepancies, were identified but did not detract from the overall positive findings.
  • Operator Training and Performance:
    • Despite approximately 40% of operators not having direct experience in plant operations due to the prolonged shutdown, KNPS has implemented rigorous training programs to ensure proficiency. All operators undergo plant startup/shutdown and accident response training, which has been assessed by third-party agencies such as the Japan Nuclear Safety Institute (JANSI) to be both practical and effective. Simulator-based training, which replicates real accident scenarios, has been elevated to a standard that should be benchmarked by other Japanese nuclear power operators. Furthermore, to strengthen operational knowledge, inexperienced operators have been dispatched to thermal power stations and pressurized water reactor plants, providing them with hands-on experience at operational facilities.
      For further details on JANSI please visit the official JANSI page.
  • Emergency Response and Risk Management:
    • The review highlighted that emergency response training has been a key focus, particularly in improving communication with regulatory agencies. Since the Fukushima Daiichi Nuclear Power Station Accident, KNPS has conducted 163 general emergency exercises (as of December 2023) and approximately 30,000 individual training sessions (as of September 2023). These extensive drills reinforce a culture of continuous, autonomous improvement. Additionally, mechanisms have been established to track and address safety risks at all levels, ensuring that even minor observations contribute to comprehensive risk mitigation efforts.

Member of the Nuclear Reform Monitoring Committee (NRMC) Dr. Charles Casto

"The review team arrived at the conclusion that TEPCO is making sound and adequate preparations for the restart of KNPS Unit 7."

Former Senior Executive Positions of U.S. Nuclear Regulatory Commission, with over 45 years of experience in nuclear operations, regulation, and oversight, Dr. Casto was a first responder to Japan in 2011, providing support during the Fukushima crisis. He is committed to ensuring the highest standards of nuclear safety and reliability at TEPCO.

Member of the Nuclear Reform Monitoring Committee (NRMC) Dr. Charles Casto

Key Findings from the NRMC Report Continued:

  • Performance Improvement and Risk Management:
    • In response to past security incidents, KNPS has developed mechanisms for continuous and autonomous improvement. By fostering safety awareness and encouraging lateral performance improvements, TEPCO seeks to elevate the basic posture of a nuclear operator, ensuring that safety remains a top priority at every level.
  • Safety Culture and Leadership:
    • Open discussions and field observations revealed no negative issues related to safety culture. Employees demonstrated a high level of morale and professionalism, underscoring a commitment to safety. The review noted that leadership continues to reinforce adherence to established procedures, with proactive safety measures such as peer checks and three-way communication protocols playing a crucial role in maintaining operational integrity.
  • Earthquake Resilience:
    • The Noto Peninsula Earthquake on January 1, 2024, had no impact on KNPS in terms of structural damage or radiation leakage. Sloshing, the movement of liquid caused by external forces such as seismic activity, was observed in the spent fuel pools of Units 2, 3, 4, 6, and 7. However, internal flooding prevention measures, including penetration waterproofing and leak containment, effectively prevented any overflow from escaping the operating floor.
  • Additional Activities Supporting Restart:
    • The review team also confirmed that, since August 2023, full-scale management observation has been conducted in pairs (one worker with one manager) to enhance auxiliary operator skills. Furthermore, only a few remaining tasks need to be completed prior to restart, with all required work having been meticulously planned.

IAEA Expert Mission Report*2

Additionally, from March 25 to April 2, 2024, international nuclear security specialists selected under IAEA visited KNPS for an expert mission which is review of nuclear facilities and activities of operators in IAEA member countries in accordance with IAEA international standards.
They checked an improvement of physical protection of nuclear materials against international nuclear security instruments established by the IAEA. The report specifically commended the management team's efforts to foster a stronger nuclear security culture at KNPS. However, it also outlined areas where further improvements are needed, with key recommendations that included:

  • Internal Threat Prevention Measures
  • Enforcement of Internal Rules and Coordination
  • Sustainable Operational Practices
  • Execution of Maintenance Plans
  • Reduction of False Alarms and Implementation of Effective Setback Countermeasures

TEPCO has committed to incorporating these recommendations into its broader defense-in-depth strategy, ensuring that KNPS remains on a path of continuous improvement in nuclear security, enhancing safety and resilience with each step forward.

Comments from International Observers

Many individuals, including distinguished guests and key figures from around the world, have visited the Kashiwazaki-Kariwa Nuclear Power Station (KNPS).

Former Ambassador Extraordinary and Plenipotentiary of the United States of America to Japan Rahm Emanuel*3

"It was very clear there were lessons learned, and new protocols and new practices put in place. The best way you learn is, when a mistake happens, don't deny it happened, but incorporate the lessons learned into new practices, new protocols, new behavior, and new rules and regulations."

Former U.S. Ambassador Rahm Emanuel's visit on November 21, 2024, provided a powerful endorsement of KNPS's ongoing safety enhancements. His remarks emphasized the importance of embracing lessons from past challenges, integrating them into new operational protocols, and continuously refining practices. His observations highlight the critical role of adaptive learning in fostering a safe and forward-looking nuclear environment, echoing the commitment that has guided improvements at KNPS for nearly 15 years.

Former Ambassador Extraordinary and Plenipotentiary of the United States of America to Japan Rahm Emanuel

Enhanced Infrastructure and Defense-in-Depth

Building on the lessons learned from the Fukushima Daiichi Nuclear Power Station Accident, KNPS has implemented a wide array of infrastructural upgrades and operational safeguards designed to withstand extreme events. These enhancements demonstrate a robust defense-in-depth strategy that protects the facility against a diverse range of risks.

  • Tsunami Protections:
    • In response to the earthquake and tsunami which triggered the Fukushima Daiichi Nuclear Power Station Accident, KNPS has implemented advanced seawalls and flood barriers designed to withstand future tsunamis. Key equipment relocated to elevated zones to ensure operational safety during natural disasters.
  • Robust Power and Cooling Systems:
    • To maintain a reliable power supply, KNPS has a diversified backup network, including emergency diesel generators and air-cooled gas turbine generator trucks (GTGs). A capacity of approximately 20,000 tons freshwater reservoir and multiple backup cooling systems guarantee effective reactor cooling in adverse conditions.
  • Hydrogen Management and Containment of Radioactive Substances:
    • Filter vent, installed to reduce the risk of atmospheric radiation release, and catalytic recombination systems, installed to manage hydrogen buildup safely are prevents potential risks, ensures reactor building integrity and mitigates the spread of radioactive substances during emergency scenarios.
  • Emergency Preparedness and Continuous Training:
    • KNPS has established rigorous emergency response protocols, including regular drills and communication exercises, ensuring staff are prepared to respond effectively during emergencies.
  • Advanced Safety and Security Systems:
    • KNPS integrates sophisticated systems for radioactive material containment and continuous radiation monitoring. Collaborative training with local authorities and strict access controls further protects the facility's personnel and materials.

For a more in-depth look at the specific safety measures and protocols in place at KNPS, please visit our detailed Safety Measures page

Ambassador Extraordinary and Plenipotentiary of the United Kingdom to Japan Julia Longbottom CMG*4

"I was impressed by how each and every member of the team worked with a sense of professionalism. Nuclear power is a low-carbon energy source and is essential to solving climate change."

Ambassador Julia Longbottom's visit on August 19, 2024, further underscores the global confidence in KNPS's safety and operational excellence. Her observations highlighted the professionalism and dedication of the KNPS team and reinforced the vital role of nuclear power as a low-carbon energy source in the fight against climate change. Her comments serve as a powerful reminder that the rigorous safety measures at KNPS not only protect the facility and its personnel but also contribute to broader environmental and societal goals.

Ambassador Extraordinary and Plenipotentiary of the United Kingdom to Japan Julia Longbottom CMG

Conclusion and Forward Outlook

The extensive independent reviews, the IAEA expert mission and international visits highlight KNPS's advancements in nuclear safety. These inspections, combined with the commitment of entire TEPCO team, underscore the station's readiness to play a pivotal role in Japan's energy. Overall, the NRMC review, held in May 2024, confirmed that critical safety issues have been addressed, with the station on track for a safe restart. While the March 2024 IAEA mission identified areas for further improvement, such as raising security standards and operational practices, these insights reflect TEPCO's commitment to continuous progress, with the feedback being integrated into the station's evolving safety measures. With no significant nuclear safety issues identified, and with a strong safety culture and robust operational practices in place, TEPCO's dedication to progress is evident across all facets of KNPS's operations. Through continuous training, cutting-edge infrastructure, and a transparent approach to safety, KNPS supports Japan's energy future. Looking forward, KNPS will remain a model for best practices, ensuring its pivotal role in energy security, economic stability, and environmental sustainability.

References

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