[Eng] Thorium Molten Salt Reactors and the Spirit of Eizaburo Nishibori

Fourteen years ago, in 2011, I first read Kazuo Furukawa’s Nuclear Safety Revolution and wrote a clumsy review, utterly captivated by the promise of thorium molten salt reactors (MSRs). It wasn’t just a safer kind of nuclear power—it felt like a vision to rewire energy itself, turning reactors into something as civic and essential as a water utility. I saw a future in it, sparked by the same audacious spirit I’d found in Eizaburo Nishibori’s You Can’t Cross a Stone Bridge by Tapping It—a book I read in my youth, which preached boldness over paralyzing caution. After Fukushima’s meltdown, with Japan stuck in a haze of distrust and inertia, I believed Nishibori’s call to action could cut through. Fast-forward to April 2025: China’s announcement of the world’s first continuously operating thorium MSR, complete with live fuel recharging, hit me like a jolt. It’s thrilling, but Japan’s stagnation leaves a lingering sense of regret. With Nishibori’s spirit as my lens, here’s a look back at the last 14 years, the tech’s progress, and what lies ahead.

My 2011 Review and Thorium Fever

Back in 2011, I called Furukawa’s book a “vista glimpsed through the trees on a mountain trail.” His thorium reactor wasn’t just an alternative to traditional nuclear—it challenged the whole arc of energy history. Drawing on Eugene Wigner’s insight that “nuclear fission is a chemical reaction, best handled in a liquid medium,” the molten salt reactor, born in the 1960s at Oak Ridge National Lab, should’ve been Japan’s post-Fukushima beacon. The “FUJI-II” concept—compact, community-friendly—sketched a future where citizens could democratically manage sustainable energy. Nishibori’s spirit dovetailed perfectly here. A mountaineer-scientist who summited Nanda Devi and shaped Japan’s nuclear program, he warned that “tapping a stone bridge” with endless caution makes crossing impossible. That boldness, I thought, was what thorium needed. Late in life, disillusioned by the nuclear establishment’s rigidity, Nishibori backed Furukawa’s MSR work with fervor. In my review, I wrote that I could “hear Nishibori’s voice clearly” and urged readers to pick up his book. Post-Fukushima, thorium felt like Japan’s shot at technological redemption. But truth be told, even I let that spark fade over the years.

What Makes Thorium MSRs Tick

Thorium MSRs use molten salt (lithium-beryllium fluoride, or FLiBe) as both fuel and coolant, converting thorium-232 into uranium-233 via neutron bombardment to drive fission. Unlike pressurized water reactors, they operate at atmospheric pressure, slashing explosion risks. If things overheat, a “freeze plug” melts, draining the molten salt into a safe tank—a passive safety feature. Thorium is 3–4 times more abundant than uranium, produces less long-lived radioactive waste, and is harder to weaponize. Challenges? The salt is corrosive, and you need uranium-235 or plutonium-239 to kick things off. But advances in materials like Hastelloy-N alloys have tamed corrosion, boosting practicality.

Over the last 14 years, while my attention drifted, the world didn’t stand still. China led the charge. In 2011, the Chinese Academy of Sciences sank $444 million into MSRs, breaking ground on a 2MWt test reactor (TMSR-LF1) in the Gobi Desert by 2018. It hit criticality in October 2023, reached full power by June 2024, and achieved in-reactor fuel recharging by October 2024, proving thorium-to-uranium-233 breeding through the detection of protactinium-233. China’s eyeing a 10MWt demo reactor by 2030 and a 100MWt commercial one in the 2030s, backed by Inner Mongolia’s thorium mines, which they claim could “power the country for tens of thousands of years.”

Elsewhere, India, sitting on 25% of global thorium, aims for 30% of its power from MSRs by 2050 but lags in molten salt tech. The U.S. (TerraPower, Flibe Energy), Denmark (Seaborg’s floating MSRs), and Europe (NRG’s salt irradiation tests) are in the game, but only China has a running reactor. My 2011 thorium dreams? They’re coming true—in China.

Japan? Stalled. Post-Fukushima mistrust, a slump in scientific ambition, and a fixation on uranium and plutonium sidelined thorium. A 2013 “Molten Salt Nuclear Applications Committee” and Furukawa’s Thorium Tech Solution carry the torch, but funding and talent are scarce.

China’s Win and What It Means

In April 2025, China’s TMSR-LF1 ran continuously, recharged fuel, and churned out 2MWt of heat, confirming fuel breeding over 10 days at full power. Mixing thorium and a dash of uranium in molten salt, it uses specialty alloys to curb corrosion. Its passive safety cuts Fukushima-style risks. Next up: a 10MWt demo reactor starting in 2025 (60MW heat, 10MW power, plus hydrogen production) and a 100MWt commercial unit in the 2030s, eyeing power, hydrogen, and ship propulsion to hit China’s 2060 carbon-neutral goal. Corrosion is being tamed with better nickel alloys and ceramic coatings; breeding cycle tweaks reduce reliance on starter fuels. Waste and regulations remain hurdles, but China has cracked open the path to commercialization. The gap’s widening. We may one day find ourselves relying on China for the very technology we once overlooked.