Before traveling to Kyoto, I spent time reading Takashi Kamei’s papers, presentations, and interviews. Anyone with an interest in advanced nuclear energy in Japan eventually comes across his work. For many years, he has explored thorium molten salt reactors, publishing research, presenting at conferences, and continuing to develop ideas in a field that still sits at the edge of the nuclear industry. That background gave me a sense of what he had been working on. It also made me curious about how he had come to see Japan’s energy future the way he does.
We met on a warm afternoon in Kyoto. Our conversation began with thorium molten salt reactors, as I thought it would. Kamei-san spoke comfortably about the technology, though the discussion soon widened. A question about reactor design led to manufacturing. Manufacturing led to supply chains and the companies capable of producing critical components. From there, we moved into artificial intelligence, the electricity demand of data centers, Japan’s industrial competitiveness, and the way public opinion shapes energy policy.
As I listened, I stopped trying to separate the conversation into subjects. Kamei-san was describing different parts of the same landscape. Reactors, factories, universities, regulators, local communities, and public trust all occupied the same map. Through that lens, it became easier to understand why someone could spend years researching a particular reactor technology while speaking just as carefully about education, politics, and manufacturing.
I had traveled to Kyoto to understand one area of advanced nuclear technology. The meeting left me thinking about the conditions that allow any technology to succeed. That way of looking at energy, patient, practical, and alert to the world around the reactor, became the thread that ran through everything we discussed that afternoon.
Kamei-san’s view of Japan’s existing nuclear plants is practical. He believes the reactors that already exist should be used where they can operate safely and responsibly. Japan has limited domestic energy resources, and reliable low-carbon electricity remains difficult to secure at scale. Existing light-water reactors are part of the infrastructure Japan has already built. They are among the few sources of steady electricity that do not depend on fossil fuels.
“I think it’s fine to keep operating the light-water reactors we already have,” he told me. “But building new ones, I think we should stop doing that.”
His caution becomes sharper when the discussion turns to building new large reactors. A conventional nuclear plant is a long commitment. It requires vast capital, years of construction, specialized components, and a supply chain that only a small number of companies can support. Once a country chooses that path, it carries the decision for decades. Kamei-san worries that Japan could extend today’s model so far into the future that it gradually loses the habit, knowledge, and flexibility needed to prepare other possibilities. The concern, as he described it, was less about rejecting what already exists and more about avoiding a future in which Japan has too few choices left.
That is how I came to understand his interest in thorium molten salt reactors. He spoke about them with the seriousness of someone who understands both the promise and the distance still to travel. Molten salt reactors remain difficult technologies. Materials, licensing, fuel handling, maintenance, and economics all require careful work. Kamei-san never made them sound easy. His point was more patient than that.
“At the very least,” he said, “I want Japan to get to the point where we know how to build thorium reactors ourselves.”
The manufacturing question seemed especially important to him. Energy security is often discussed in terms of fuel imports, though a nuclear plant is also a product of heavy industry. It depends on metallurgy, precision engineering, quality control, and workers who know how to build things that leave almost no room for error. Large reactor components, including pressure vessels, are not products any country can simply decide to manufacture overnight. They require facilities, experience, and a continuity of skill.
Kamei-san pointed to Japan Steel Works in Hokkaido as an example of how concentrated some of these capabilities can become. In his view, this kind of industrial bottleneck helps explain why smaller advanced reactor designs attract interest overseas. If a country can build more of the supply chain domestically, the reactor becomes more than an energy technology. It becomes part of an industrial strategy. He also argued that smaller systems could reduce the financial risk of experimentation: a large reactor can become a decades-long commitment, while a smaller design, if it proves workable, may allow countries and companies to learn without betting the entire system at once.
This is one reason Kamei-san watches developments overseas with interest. In the United States, nuclear energy has begun to enter the business plans of major technology companies. Artificial intelligence and data centers are increasing demand for electricity that is available day and night. Microsoft, Google, and Amazon have each announced nuclear-related agreements in recent years, including plans connected to reactor restarts and advanced reactor development. These projects still face practical hurdles, though they show that reliable low-carbon electricity has become part of industrial strategy.
For Japan, that shift deserves attention. If other countries use the growth of AI and data infrastructure to rebuild nuclear supply chains, train engineers, and test advanced reactors, Japan may later find itself responding from behind.
“Japan really does have this ‘black ships’ culture,” Kamei-san said, almost lightly. “Something happens from outside, and everyone suddenly panics and scrambles.”
He used the phrase calmly, almost as a reminder about timing. A country can respond after the world changes. Preparation gives it another position entirely.
The same sense of preparation shaped his comments on public acceptance. During the conversation, I shared the idea of creating WePlanet Japan, connected to the broader international movement that supports science-based solutions to climate and energy challenges. In Europe, pro-nuclear environmental groups sometimes use demonstrations and public campaigns to call for nuclear restarts or new nuclear development. Kamei-san immediately focused on how that kind of effort would need to take root in Japan.
He asked what such an organization would actually do here. He asked how it would sustain itself, who would lead it, and what success would look like. He also understood that credibility in Japan would have to be earned in a Japanese way. Public campaigns that work in Europe cannot simply be carried across the world and translated into Japanese. The message, the messengers, and the method all have to fit the society they hope to reach.
“Japan tends to follow whatever comes down from above,” he said, describing a culture where authority and consensus move differently than in Europe.
Those questions stayed with me because they were concrete. Kamei-san was taking the idea seriously enough to test its foundations. Enthusiasm would not be enough. A Japanese organization would need patience, judgment, and people trusted enough to help a difficult conversation move forward. He mentioned, almost as an aside, that the group would likely need advisors, people with real standing in the nuclear field who could lend the effort a depth that younger organizers, however sincere, might not yet have on their own.
That point is easy to underestimate. Japan’s nuclear conversation still carries the memory of the Fukushima Daiichi nuclear accident. For many people, nuclear energy is connected with evacuation, contamination, institutional failure, and a loss of trust. Anyone who wants a better conversation about nuclear power has to begin from that reality. Public concern cannot be brushed aside as misunderstanding. Trust has to be earned again, slowly and concretely.
At the same time, avoiding difficult energy choices has consequences of its own. Imported fossil fuels affect energy security and emissions. Renewables are essential, but integrating variable power requires grids, storage, backup capacity, and careful planning. Industrial competitiveness depends on reliable electricity. Climate goals depend on choices that work in the real world, under real constraints. Kamei-san’s way of speaking kept returning to these trade-offs. He was asking Japan to look steadily at all of them.
Near the end of our conversation, I asked what message he would give to young people.
“I want you to hold on to a sense of crisis,” he said. “We don’t feel danger the way earlier generations did, but I want you to carry that awareness as your own, not to be too afraid, but to hold on to hope for the future. The safety and peace we have now didn’t just happen on their own. If we want to keep it, we have to be the ones who act.”
The answer was simple, and it matched the rest of the afternoon. Stability is something each generation inherits, then maintains or weakens. Electricity, industry, public trust, and technological skill remain strong only when people continue to care for them.
Thorium molten salt reactors are the technology Kamei-san has spent years studying, but his larger concern is readiness. Japan still has engineers, universities, companies, operating experience, and young people willing to engage with nuclear energy seriously. These strengths will fade if the country treats energy policy as something to revisit only after the next crisis arrives.
On the train back from Kyoto, I kept returning to one idea from the conversation. Japan’s nuclear future will be shaped by reactor designs, and also by the people, industries, institutions, and public trust that make those designs possible. Technology does not arrive in society by itself. It needs builders, explainers, regulators, communities, and citizens willing to consider difficult choices with care.
Kamei-san’s message was quiet, which made it feel more serious. He was asking Japan to keep its ability to decide alive. For a country facing rising electricity demand, climate pressure, industrial competition, and an uncertain technological future, that ability may become as important as any single reactor design.