Restart Hailed as Milestone Before Abrupt Suspension
Japan’s efforts to reinvigorate its nuclear energy sector suffered an early setback this week after the No. 6 reactor at the Kashiwazaki‑Kariwa nuclear power plant was suspended only hours after its restart. The move came just a day after operations officially resumed, marking TEPCO’s first reactor restart since the 2011 Fukushima disaster — and underscoring lingering technical and safety challenges in the nation’s nuclear revival.
The Kashiwazaki‑Kariwa facility, located in Niigata Prefecture on Japan’s north‑central coast, is recognized as the world’s largest nuclear power plant by generating capacity, with seven reactors totaling about 8.2 gigawatts. Reactor No. 6, which restarted on January 21, 2026, was expected to contribute roughly 1.35 million kilowatts — enough to power over one million homes — when it enters full commercial operation.
Technical Glitch Prompts Safety Shutdown
The restart process was interrupted when an alarm triggered during startup procedures, linked to a malfunction in control rod equipment. Control rods — critical to managing the nuclear chain reaction — must operate flawlessly to ensure safe reactor control. TEPCO officials said the alarm occurred as workers withdrew some of the rods from the core in preparation for full power.
Reactors undergo a phased startup that includes careful monitoring at each stage. In this case, the company reported that no radioactive release or safety breach occurred, and the unit remained “stable” during the incident. Nevertheless, operators re‑inserted control rods in a planned sequence, halting the restart and placing the reactor once more into a safe shutdown condition while further inspections take place.
TEPCO has not provided a timeline for resuming the restart, saying investigations into the malfunction are ongoing and that safety cannot be compromised. The utility also noted that an earlier alarm‑related delay had briefly postponed the restart scheduled for January 20, reflecting persistent systems testing challenges.
Historical Context: Nuclear Restart in Post‑Fukushima Japan
The Kashiwazaki‑Kariwa restart was touted as a symbolic milestone for Japan’s nuclear industry, coming nearly 15 years after the Fukushima Daiichi nuclear disaster. In March 2011, a massive earthquake and tsunami crippled that plant, triggering reactor meltdowns and a widespread evacuation. In the aftermath, Japan shut down all of its reactors to reassess safety standards, regulatory frameworks, and disaster preparedness.
Since then, a number of reactors across the country have gradually returned to service under revised safety regulations, but progress has been slow. Kashiwazaki‑Kariwa — operated by Tokyo Electric Power Company Holdings (TEPCO), the same firm that managed Fukushima — had remained idle since the disaster and has been the subject of intense scrutiny and public debate.
The plant’s restart was also controversial locally. Surveys and protests in Niigata revealed deep divisions: many residents expressed concerns about seismic risks and emergency preparedness, while others welcomed the economic and energy security benefits of reactivating the facility.
Energy Policy and Economic Pressures
Japan’s renewed nuclear push is driven by multiple pressures. The nation, which lacks indigenous fossil fuel resources, faces rising energy import costs, growing electricity demand — particularly from data centers and industrial sectors — and ambitious carbon‑reduction goals tied to decarbonization commitments by mid‑century. Nuclear power is seen by many policymakers as a key component of meeting these challenges.
Reactivating large plants like Kashiwazaki‑Kariwa also eases reliance on costly liquefied natural gas and coal, which have historically supplied much of Japan’s electricity since the post‑Fukushima shutdowns. However, technical setbacks like the recent suspension underscore the complex balance between energy needs and operational safety.
Regulatory and Public Confidence Issues
TEPCO’s reputation remains mixed. While the company has invested billions in safety upgrades and regulatory compliance, its handling of Fukushima and subsequent operational issues have left public trust fragile. The latest malfunction adds pressure on both the utility and the Nuclear Regulation Authority (NRA) to demonstrate that stringent oversight and modern safety protocols are effective.
Experts note that ensuring transparency and rigorous technical verification — especially in quake‑prone Japan — is essential to rebuilding confidence. The Kashiwazaki‑Kariwa incident comes amid other concerns in the sector, including recent controversies over seismic data and safety reviews at other facilities, which have at times shaken regulatory credibility.
Looking Ahead: What the Suspension Means for Japan’s Nuclear Future
The suspension highlights the inherent challenges in reviving nuclear power in a country with high seismicity and a population sensitive to nuclear risks. While the immediate technical issue has not posed health hazards, it has delayed efforts to bring a major power source online at a critical time.
For TEPCO and Japan’s broader energy strategy, the focus now lies on diagnosing the control rod glitch, reassuring regulators and the public, and resuming preparations for eventual commercial operation. How quickly and transparently these steps unfold may influence future nuclear restarts, investor confidence, and wider debates over the role of nuclear energy in meeting climate and economic goals.
As Japan navigates these complex energy decisions, the Kashiwazaki‑Kariwa suspension serves as a stark reminder that technical precision, regulatory rigor, and public trust must align for nuclear energy to play a stable role in the nation’s power mix.
