Interview at COP 30 — Prof. Jun Arima, Visiting Professor, University of Tokyo

At the Net Zero Nuclear Pavilion at COP30 in Belém, Brazil, we spoke with Professor Jun Arima, Board Member of the Japan Atomic Industrial Forum (JAIF) and Visiting Professor at the University of Tokyo. With decades of experience in global climate negotiations, Professor Arima reflected on how nuclear energy’s standing at the COP has evolved, the major shifts in Japan’s new energy strategy, and what must happen next to deliver the ambition of the global pledge to triple nuclear capacity by 2050.

Key Themes from the Interview

A New Global Context for Nuclear

Professor Arima noted that nuclear energy’s resurgence is rooted in a rapidly shifting geopolitical and energy landscape. He highlighted several drivers:

- Russia’s invasion of Ukraine

- Conflict in the Middle East

- Rising geopolitical energy risks

- Increasing ambition under the Paris Agreement

These forces have made it harder for countries to balance energy security, climate action, and affordability. Against this backdrop, nuclear has regained attention as a source of massive, stable, carbon-free baseload power.

Renewables remain essential, he emphasised, but their intermittency and grid integration challenges mean they cannot deliver net zero alone.

COP28 as a Turning Point

Professor Arima pointed to COP28 as a pivotal moment. While much of the debate that year focused on fossil fuel phase-out, something equally significant happened:

- Nuclear was recognised for the first time as a zero- and low-carbon technology, alongside renewables, CCS, and hydrogen.

- More than 20 countries signed a voluntary pledge to triple nuclear capacity by 2050.

For someone who participated in COP negotiations as early as COP6 and COP7—when nuclear was excluded from Kyoto credits and often treated as a contentious technology—this shift represents a move from ideology to pragmatism in global energy debates.

Japan’s 7th Strategic Energy Plan: A Major Break with the Past

In February 2025, Japan adopted its 7th Strategic Energy Plan, marking a decisive change in national energy policy.

For the first time, the government removed long-standing language about “reducing nuclear dependency as much as possible,” a phrase that had shaped Japanese policy since 2012.

Japan’s new approach is not renewable or nuclear—but renewable and nuclear, treating both as essential low-carbon technologies.

Key elements of the new plan include:

- A target for nuclear to supply 20% of total power generation by 2040, even as electricity demand grows due to AI, data centres, and semiconductor manufacturing

- Recognition that current high electricity prices—especially compared to other Asian economies—are straining households and industry

- Evidence that regions with reactor restarts (e.g., Kansai and Kyushu) benefit from lower electricity prices, shifting public sentiment

Japan’s media surveys now show clear signs of a more favourable public attitude toward nuclear energy.

Why Nuclear Is Increasingly Indispensable for Japan’s Climate Goals

Professor Arima explained that all scenarios in Japan’s new plan assume substantial cost reductions in renewables, CCS, hydrogen, and other low-carbon technologies.

But the government also includes a “risk scenario” where these cost reductions do not materialise.
In those cases, the role of nuclear becomes even more critical.

Without nuclear, he warned, Japan cannot meet its ambitious CO₂ reduction targets.

Enabling New Nuclear Construction

To translate policy ambition into real-world deployment, Japan must build a stronger enabling environment for new nuclear, including:

- Long-term investment recovery mechanisms to support capital-intensive projects

- Rationalised, cost-effective safety regulations

- Continued application of Japan’s “3E+S” framework: safety, energy security, economic efficiency, and environment

- Reassessment of unlimited liability rules for nuclear operators

Professor Arima emphasised that strong political leadership is essential. Japan’s new Prime Minister, Sanae Takaichi, has placed energy security at the centre of her agenda and is openly supportive of both nuclear and fusion—an important signal for the sector.

The Future of Nuclear at COP and Globally

Looking ahead, Professor Arima sees momentum for nuclear strengthening across both developed and developing countries. Many nations now face rising electricity costs and growing concerns about affordability and industrial competitiveness.

But he cautioned that without action, much of the new global nuclear capacity could be built in China alone, which he said would be far from ideal. To avoid this imbalance and achieve the global goal to triple nuclear capacity, countries must invest in:

- Public-private partnerships

- Innovative reactor technologies, including SMRs

- New applications, such as nuclear-powered hydrogen production

- Shared, international supply chains

These steps are essential for diversifying global nuclear growth and ensuring nuclear energy strengthens both climate progress and energy security worldwide.

Watch the Full Interview

View the full conversation on the World Nuclear Association’s YouTube channel to hear Professor Jun Arima’s insights on Japan’s new energy strategy, the shifting politics of nuclear at COP, and the actions needed to achieve the global ambition to triple nuclear capacity by 2050.