Japan’s Nuclear Restart: Unlocking a 30+ GW Market for Global Nuclear Business
As global nuclear markets confront cost hikes, regulatory uncertainty, and geopolitical risk, one of the world’s most advanced nuclear programmes is quietly transitioning from caution to credible execution. Japan, a market once sidelined in nuclear investment conversations, is emerging as a structured and investable arena for vendors, service providers, and capital allocators seeking predictable returns in an otherwise fragmented industry.
Japan’s nuclear landscape today reflects strategic recalibration rather than revivalist rhetoric. After years of phased restarts under rigorous safety regimes, driven by an independent regulator and reinforced by strategic energy planning, nuclear power is regaining a material role in Japan’s energy mix. For global nuclear business stakeholders, this shift is not abstract: it is a measurable, policy-anchored re-entry with clear demand signals, regulatory clarity, and long-term operational horizons.
Reactivating a Large Asset Base with Global Relevance
Japan possesses one of the world’s largest nuclear asset bases, with 33 reactors classified as operable and a combined capacity of nearly 31,679 MWe—comparable in scale to the largest nuclear portfolios in other mature markets. However, much of this capacity remained dormant for over a decade following the 2011 Fukushima accident, as extensive safety upgrades and rigorous regulatory reviews led to prolonged reactor shutdowns and fundamentally reshaped the sector’s trajectory.
The operational landscape has now shifted in a meaningful way. Fifteen reactors have already been restarted and are back in service after meeting stringent post-Fukushima regulatory requirements, while a further ten operable units are progressing through various stages of restart approval, underscoring the depth of the restart pipeline. In addition, two reactors—Ohma and Shimane Unit 3—which were previously under construction, have applied for construction or restart approvals, extending Japan’s mid-term nuclear outlook. Taken together, this represents not a marginal recovery but a phased reactivation of a substantial existing fleet, unlocking millions of megawatt-hours of potential generation under a framework of renewed regulatory certainty.
Regulatory Certainty as an Investment Signal
At the core of Japan’s relaunch is the Nuclear Regulation Authority (NRA) — a post-2011 institution charged with establishing new safety requirements that now define licensing and restart criteria. This regulator’s independent authority and rigorous safety frameworks have created a transparent and predictable environment for asset restarts, which is precisely what capital markets and vendors value most in nuclear deployment cycles.
Key regulatory developments that enhance investability include:
Operating licences remain at a standard 40-year term, but extensions to 60 years are now clearly possible subject to NRA approval, enabling long-term asset depreciation schedules.
In June 2025, a pivotal rule came into force allowing offline periods (due to regulatory reviews) to be excluded from the lifetime limit, materially improving the economic horizon for extended operations.
The 7th Strategic Energy Plan released in February 2025 explicitly reaffirmed nuclear’s role and removed prior language about reducing dependency on nuclear power, signaling stable policy orientation.
These changes transform regulatory risk — historically one of the largest deterrents for nuclear financing — into a structural advantage. They institutionalize safe operation while enabling investors and counterparties to stake capital with confidence.
Electricity Mix and Strategic Necessity
Japan’s nuclear trajectory is not unfolding in a policy vacuum but is instead being driven by clearly defined energy system constraints and long-term strategic goals. In 2023, nuclear power accounted for roughly 8% of the country’s electricity generation, a modest contribution compared to pre-Fukushima levels. However, current national energy targets signal a decisive shift, with nuclear expected to supply around 20% of electricity by 2030 and to retain a sustained presence in the energy mix through the 2040s.
This recalibration reflects several converging imperatives. Japan remains highly dependent on imported fossil fuels, leaving its economy exposed to global price volatility and persistent energy security risks. At the same time, while renewable capacity continues to expand, it cannot fully replace firm baseload generation without extensive and costly grid reinforcement and storage deployment. Within this context, nuclear restarts provide a scalable source of reliable, low-carbon baseload power and form a critical pillar of decarbonization strategies that seek to integrate renewables without compromising system stability.
For suppliers, investors, and financiers, the implication is clear: Japan is not pursuing reactor restarts as a symbolic or transitional measure, but is actively reconstructing a balanced electricity portfolio in which nuclear energy occupies a defined, durable, and strategic role.
Execution Momentum and Business Credibility
The practical progress of restarts — including units such as Genkai 3 & 4, Takahama 1–2, Onagawa 2, and Shimane 2 — demonstrates that regulatory rigor has translated into operational momentum. Each restart requires meticulous safety upgrades, community engagement, and capital commitment. For nuclear vendors and service providers, this translates into sustained demand for upgrades, technical services, and long-term operational support.
The reactivation of Kashiwazaki-Kariwa Unit 6, one of the world’s largest reactors at 1.36 GW, is particularly significant. Fuel loading and approval movements at this site are not just a domestic milestone — they are a global signal of confidence that large nuclear assets can be returned to service with predictable outcomes and transparent governance.
Long-Term Opportunity Across the Value Chain
Japan’s nuclear evolution offers multiple layers of commercial opportunity:
1. Restart and Life Extension: With life extensions sanctioned and ageing reactors returning, there is demand for engineering upgrades, safety improvements, control system modernisation, and long-term maintenance contracts.
2. Fuel and Services: Restarted reactors underpin predictable nuclear fuel cycles, including procurement, fabrication, and spent fuel management services, all of which favour long-term agreements with strong creditworthy utilities.
3. Regulatory and Advisory Engagement: The NRA’s procedures and compliance frameworks, while stable, create demand for consulting, training, and regulatory support services, especially for foreign firms entering the Japanese market.
4. Future Build Optionality: Though new large-scale plant construction is measured, the government’s inclusion of advanced reactors and potential builds post-Fukushima signals optional expansion windows over the 2030s and beyond.
Together, these pathways create a multi-decade commercial landscape, not a short-term project window. This is the kind of predictability that underpins infrastructure-grade capital and long-duration service contracts.
Moving Forward
Japan’s nuclear restart is shaping up as one of the most structured and investable market stories in the global nuclear industry. What was once perceived as a paused or politically constrained programme has evolved into a rules-based, policy-driven, capital-ready opportunity, underpinned by regulatory credibility and long-term strategic intent.
With a significant share of its reactor fleet poised to return to service, updated lifetime frameworks restoring economic value to existing assets, and strategic energy targets firmly embedding nuclear in long-term planning, Japan’s nuclear sector is increasingly difficult for serious market participants to ignore. The direction of travel is clear: this is a market moving from regulatory recovery toward operational scale and commercial normalisation.
That momentum will be tested, refined, and increasingly internationalised through platforms such as the 11th Asia Nuclear Business Platform (ANBP) 2026, scheduled for 3–5 November in Hanoi, Vietnam. The high-level gathering is expected to convene policymakers, investors, global vendors, and regional stakeholders to align investment frameworks, secure long-term partnerships, and clarify procurement pathways across Asia’s nuclear markets — with Japan’s restart trajectory standing out as a key reference point.
For utilities, vendors, fuel suppliers, EPC firms, and financiers, the opportunity in Japan is not speculative. It is a restart anchored in regulatory certainty, execution momentum, and energy-security pragmatism. As the global nuclear industry looks toward the 2030s, Japan is not merely returning to the table — it is opening a confident and increasingly bankable door for business.
