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Kashiwazaki-Kariwa reactor resumes operations after 13-year hiatus
Japan has reactivated the sixth reactor at the Kashiwazaki-Kariwa nuclear plant, marking the first restart of a Tokyo Electric Power Company (Tepco) facility since the 2011 Fukushima catastrophe. The move comes despite persistent safety concerns from local residents and a one-day delay caused by an alarm malfunction.
Fukushima's lasting shadow
The 2011 earthquake and tsunami triggered meltdowns at the Fukushima Daiichi plant, forcing Japan to shut all 54 of its nuclear reactors. The disaster, labeled a "man-made" failure by an independent government report, eroded public trust in nuclear energy. While a court later cleared three Tepco executives of negligence, thousands of evacuees remain displaced, and many have not returned despite official safety assurances.
Public opposition surged immediately after the disaster, with 70% of Japanese favoring reduced nuclear use by 2012, according to Pew Research Center. Though support has since rebounded-over 50% now back nuclear power if safety is guaranteed-distrust lingers, fueled by scandals and the 2023 release of treated radioactive water from Fukushima.
Japan's cautious nuclear revival
Before 2011, nuclear power supplied nearly 30% of Japan's electricity, with plans to expand to 50% by 2030. Today, the government's target is far more modest: 20% by 2040. As of 2023, nuclear accounted for just 8.5% of the country's energy mix, with only 15 of 33 operable reactors back online.
Prime Minister Sanae Takaichi has framed nuclear energy as critical to Japan's energy independence, particularly as demand rises from data centers and semiconductor manufacturing. Yet critics argue the focus on nuclear has diverted investment from renewables, despite Japan's mountainous terrain limiting solar and wind expansion.
Economic and safety hurdles
Restarting reactors has proven costly, with new safety regulations requiring billions in upgrades. Dr. Florentine Koppenborg of the Technical University of Munich notes that nuclear power is now "far more expensive than anticipated," forcing the government to choose between subsidies or higher consumer bills-both politically unpopular options.
Recent scandals have further shaken confidence. In 2023, a Tepco employee lost confidential documents after leaving them on a car roof, while another mishandled sensitive files. Though Tepco claims it reported the incidents to regulators, Koppenborg warns the company "struggles to change its safety culture."
This month, the Nuclear Regulation Authority (NRA) suspended its review of Chubu Electric's Hamaoka plant after the company admitted falsifying earthquake data. Hisanori Nei, a former senior nuclear safety official, called the penalty a deterrent but stressed that "authorities will reject and punish" future violations.
Prepared for the past, not the future
Post-Fukushima safety upgrades include 15-meter seawalls and watertight doors at Kashiwazaki-Kariwa. Nei asserts these measures could withstand a repeat of the 2011 disaster, but Koppenborg cautions they may not account for climate change or a "once-in-a-century megaquake."
"If the past repeats itself, Japan is super well-prepared. If something unexpected happens, we don't know."
Dr. Florentine Koppenborg, Technical University of Munich
Local opposition remains vocal. In December, hundreds protested outside the Niigata prefectural assembly, with one demonstrator telling Reuters, "If something happens at the plant, we suffer the consequences." Last week, activists gathered outside Tepco's headquarters ahead of the restart.
Uncertain path forward
The seventh reactor at Kashiwazaki-Kariwa is not expected to restart until 2030, while the remaining five may be decommissioned. The plant's capacity will shrink to 8.2 gigawatts-less than half its pre-2011 output.
Despite global momentum for nuclear energy, Japan's revival faces steep challenges. Koppenborg describes the restart as "a drop on a hot stone," unlikely to reverse the broader decline of nuclear power in the country.
