Nuclear Energy Weekly Digest

nuclear Dec 28, 2025

Week 52 (December 22–28, 2025)

Japan Approves Kashiwazaki-Kariwa Restart with January 20 Operational Target

The Niigata Prefecture Assembly formally approved the partial restart of Kashiwazaki-Kariwa nuclear power plant on December 22, 2025, clearing the final major administrative hurdle for reactivating Japan's largest nuclear facility and breaking TEPCO's 14-year operational pause following the Fukushima Daiichi disaster. Governor Hideyo Hanazumi subsequently provided formal local government consent on December 23, enabling TEPCO to proceed with final safety inspections from the Nuclear Regulation Authority. TEPCO announced that Unit 6, with 1,360 MWe capacity, would commence operations on January 20, 2026, representing the first reactor restart by TEPCO since the March 2011 triple meltdown that forced national shutdown of 54 reactors and precipitated Japan's decade-long near-complete nuclear moratorium.[2][3][4][1]

Kashiwazaki-Kariwa, comprising seven reactors with combined capacity of 8.2 GW—making it the world's largest nuclear facility—had remained offline since 2012 despite Units 6 and 7 clearing safety assessments in 2017, with restart preparations subsequently suspended following safeguarding violations discovered in 2021. The plant's February 14 drone strike suffered during Ukraine-related military incidents and the January 1, 2024, Noto Regional earthquake intensified local safety concerns, requiring sustained government engagement to secure restart approval. TEPCO President Tomiaki Kobayakawa publicly committed that "as the company responsible for the Fukushima Daiichi accident, we will apply the reflections and lessons learned," emphasising that safety constitutes the paramount priority across all restart phases. Unit 6 restart will augment Tokyo region electricity supply by approximately 2 percent, while TEPCO anticipates Unit 7 recommencing by 2030, with potential decommissioning of the plant's remaining five oldest reactors, substantially reducing near-term operational risks from ageing equipment and seismic vulnerability.[3][4][1][2]

New York and Ontario Establish Historic Nuclear Cooperation Framework

New York Governor Kathy Hochul and Ontario Premier Doug Ford signed a landmark agreement on December 19, 2025, in Buffalo, establishing a comprehensive bilateral framework for advanced nuclear energy technology development, deployment, and cross-border electricity trade expansion. The declaration of intent encompasses cooperation on large-scale reactor construction and small modular reactor deployment, workforce development initiatives, public education on nuclear benefits, and exploration of opportunities to expand the estimated $39 billion annual two-way trade between the jurisdictions through enhanced cross-border electricity commerce.[5][6][7]

Ontario Power Generation (OPG) and the New York Power Authority (NYPA) simultaneously signed a Memorandum of Understanding committing both utilities to leverage Ontario's "global nuclear leadership" through information sharing, expertise deployment, and joint project identification across technological innovation, nuclear financing and economics evaluation, and workforce development. The agreement reflects Ontario's position as the first G7 nation to commit to large-scale small modular reactor deployment, with four 300 MWe BWRX-300 units under construction at Darlington Nuclear Generating Station projected to deliver 1,200 MWe combined capacity sufficient for 1.2 million homes by 2035. New York's participation signals the state's commitment to "positioning itself at the forefront of advanced nuclear technology deployment," driven by surging electricity demand from data centers, artificial intelligence applications, and electrification initiatives requiring stable, carbon-free baseload generation. The bilateral partnership strengthens North American nuclear supply chains, establishes manufacturing and expertise coordination, and creates investment frameworks supporting private sector participation in nuclear expansion initiatives critical to both jurisdictions' energy security and climate mitigation strategies.[6][7][5]

Sweden Receives First State Aid Application for New Nuclear Construction

Videberg Kraft AB, a project company jointly held by Vattenfall and backed by the Industrikraft industrial consortium, submitted the first application for government state aid supporting new nuclear construction in Sweden on December 23, 2025, under legislation authorising state financing and risk-sharing mechanisms that entered into force on August 1, 2025. The application seeks government financing and two-way contracts for difference to support development of either five GE Vernova Hitachi BWRX-300 small modular reactors or alternative Rolls-Royce SMR units on the Värö Peninsula, with final reactor technology selection anticipated in 2026.[8][9][10]

Swedish state aid legislation permits loans and two-way contracts for difference protecting project operators from commodity price fluctuations while ensuring government protection from excessive returns during high-price periods. Total government support is capped at approximately 5,000 MW of installed capacity—equivalent to four large-scale reactors—with loans available for construction, testing, planning, and preparatory measures, and contracts for difference applicable once reactors reach full operational status. The Industrikraft consortium comprises nine leading Swedish industrial companies including ABB, Alfa Laval, Boliden, Hitachi Energy, Höganäs AB, SSAB, Saab, Stora Enso, and Volvo Group, reflecting broad industrial support for new nuclear capacity expansion. Ministry of Finance processing will encompass government-applicant negotiations regarding support conditions and scope, with anticipated European Commission dialogue regarding state aid rule compliance—a process mirroring Poland's recent successful approval for financing its first commercial nuclear power plant. Swedish government officials noted that, based on preliminary discussions, additional state aid applications from other project proposers are likely to follow, indicating intensifying Swedish commitment to nuclear expansion as a pillar of energy sovereignty and industrial decarbonisation.[9][10][8]

China Launches HTGR Industrial Alliance to Accelerate Fourth-Generation Reactor Commercialisation

China National Nuclear Corporation subsidiary Chinergy launched the High-Temperature Gas-Cooled Reactor (HTGR) Modern Industrial Chain Alliance on December 11, 2025, in Beijing, bringing together more than 60 organisations from upstream and downstream sectors of the high-temperature reactor industry. The alliance initiative, undertaken with strategic guidance from China Huaneng Group and Tsinghua University, aims to "build a strategic community with shared goals, responsibilities, benefits, and values, marking a key milestone in the industrialisation and collaborative innovation of China's fourth-generation nuclear energy technology."[11][12]

The HTGR represents a proliferation-resistant, inherently safe fourth-generation advanced reactor technology featuring versatile applications across electricity generation, direct heat delivery for industrial processes, and steam production for desalination and enhanced oil recovery operations. The alliance focuses on comprehensive value chain coordination encompassing research and design, fuel manufacturing, equipment manufacturing, construction, installation, commissioning, operation and maintenance, and international market development. HTGR technology offers particular advantages for industrial heat applications in steel production, cement manufacturing, and petrochemical refining, where simultaneous electricity and process heat generation enables unprecedented thermodynamic efficiency and emissions reduction compared to conventional combined-cycle natural gas facilities. China's strategic positioning of the HTGR industrial alliance reflects determination to establish global technological and manufacturing leadership in fourth-generation reactors before Western competitors commercialise competing designs, leveraging Chinese manufacturing scale advantages and integrated supply chains spanning component production through reactor assembly and commissioning.[12][11]

Kazakhstan and Japan Expand Nuclear Cooperation During Presidential Visit

President Kassym-Jomart Tokayev's official visit to Japan from December 18–20, 2025, culminated in bilateral agreements encompassing uranium supply security, reactor technology research, spent fuel management, and training cooperation valued at approximately USD 3.72 billion. Kazatomprom, the world's largest uranium producer, and Kansai Electric Power Company signed a uranium supply agreement securing supply of Kazakh uranium oxide for Kansai's seven reactors across the Mihama, Takahama, and Ohi power stations, establishing a sustainable supply chain for Japan's nuclear sector during the nation's gradual fleet restart.[13][14][15]

The bilateral framework encompassed four memoranda of understanding and cooperation agreements: First, a Memorandum of Cooperation on research and development of high-temperature gas-cooled reactors between Kazakhstan's Atomic Energy Agency and the Japan Atomic Energy Agency (JAEA), supporting joint exploration of fourth-generation reactor technologies applicable to industrial heat production and advanced electricity generation. Second, a Memorandum on strengthening cooperation in applied research between the Atomic Energy Agency and JAEA, facilitating technology transfer and joint research initiatives. Third, a Memorandum of Cooperation on expanding scientific ties between Kazakhstan's National Nuclear Center and Marubeni Utility Services Ltd, supporting workforce development and technical exchange. Fourth, a Memorandum of Understanding on spent nuclear fuel and radioactive waste management between the NNC and Muroosystems Corporation, addressing critical back-end fuel cycle challenges.[14][15][13]

During his address to the First Central Asia-Japan Dialogue Summit, President Tokayev emphasised that "the combination of Kazakhstan's resource potential and Japan's advanced nuclear technologies opens up favourable opportunities for successful cooperation," highlighting particular interest in nuclear waste management, safety enhancement, and training of specialised personnel in civil protection fields. The agreements reflect Japan's strategic reassessment prioritising nuclear energy for energy security and emissions reduction following years of dependence on imported fossil fuels, positioning Kazakhstan as a critical long-term uranium supplier and technology partner for Japan's nuclear sector expansion through 2050.[15][13][14]

Global Nuclear Fuel Introduces GNF4 Next-Generation Boiling Water Reactor Fuel

Global Nuclear Fuel (GNF), a GE Vernova-Hitachi alliance company, introduced GNF4, a next-generation boiling water reactor fuel product leveraging 60 years of design innovation and operating history accumulated through deployment of GNF2 and GNF3 fuel variants across global utility fleets. The GNF4 design incorporates two advanced components licensed by the US Nuclear Regulatory Commission: Ziron cladding technology and aluminosilicate-doped uranium dioxide fuel pellets, enabling substantially enhanced reactor performance, reliability, and economics compared to existing fuel products.[16][17]

GNF4 is engineered to deliver plant operators reduced fuel costs per megawatt-hour through enhanced burnup capability, improved thermal conductivity and mechanical properties of fuel pellets, and superior corrosion resistance and strength characteristics of Ziron cladding compared to traditional zirconium-based materials. The first lead use assemblies of GNF4 are contracted for deployment in commercial reactors in 2026, with full reload quantities expected to achieve availability in 2030, enabling utilities to incrementally integrate advanced fuel into operations while accumulating operational experience and validation data supporting broader fleet deployment. Manufacturing of GNF4 occurs at GNF's Wilmington, North Carolina facility, positioning the company to support expanding reactor deployments across both existing utility fleets and new construction projects, with particular applicability to advanced reactor designs incorporating boiling water reactor thermal-hydraulics and fuel assembly configurations.[17][16]

Restart of Kashiwazaki-Kariwa Progresses Toward January Operations

TEPCO submitted Unit 6 for final safety inspection by Japan's Nuclear Regulation Authority in December 2025, with formal NRA assessment procedures anticipated to culminate in operational approval enabling January 20, 2026 startup. The restart represents not only TEPCO's first reactor reactivation since Fukushima Daiichi but also marks the first operational approval for any utility directly responsible for the 2011 disaster, establishing psychological and institutional importance for national nuclear policy recovery and public confidence rehabilitation. Restart preparations for Unit 7 advanced with estimated commissioning by 2030, with TEPCO simultaneously evaluating potential permanent closure decisions for Units 1–5, the oldest reactors at Kashiwazaki-Kariwa, prioritising seismic safety and component ageing considerations.[4][1][2][3]

Nuclear Arms Control Architecture Under Pressure in 2026

International nuclear non-proliferation frameworks face heightened systemic stress entering 2026, with the bilateral US-Russia New START Treaty expiring on February 5, 2026, and the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Review Conference scheduled for April 2025 in New York expected to encounter similar consensus failures that prevented final document adoption at prior 2015 and 2020 sessions. The international nuclear landscape darkened throughout 2025 following US strikes on Iranian nuclear facilities, Russia's testing of the nuclear-powered cruise missile Burevestnik, and President Trump's references to potential resumption of nuclear testing, collectively signalling deteriorating diplomatic engagement on strategic arms limitations.[18]

The Bulletin of the Atomic Scientists and international experts assess global nuclear deterrence architecture as increasingly destabilised by China's rapid strategic nuclear expansion—reportedly manufacturing 100 warheads annually—and technological convergence between nuclear and conventional forces including hypersonic weapons and advanced air defence systems that complicate traditional deterrence calculations. Anton Khlopkov, director of Russia's Center for Energy and Security Studies, characterised the strategic environment as "on the verge of an almost complete dismantling of the arms control architecture," with inspection components of New START no longer functional and interstate reliance reduced to voluntary compliance commitments increasingly questioned by major powers. The geopolitical implications extend beyond strategic parity calculations, affecting international cooperation frameworks essential for advancing civilian nuclear technologies, fuel cycle security, and non-proliferation compliance across developing nations pursuing nuclear energy for electricity generation and industrial applications.[18]