'No longer a fantasy': China claims Japan has enough plutonium for 5,500 nuclear warheads

China has renewed its warnings about Japan's nuclear potential, with its ambassador to Russia claiming that Tokyo possesses enough plutonium to theoretically produce thousands of nuclear warheads.

In an article published by Russia's state-run TASS news agency, Chinese Ambassador to Russia Zhang Hanhui said Japan had 44.4 tonnes of plutonium extracted from spent nuclear fuel as of the end of 2024. He claimed the stockpile could be used to manufacture around 5,500 nuclear warheads.

The ambassador also said Japan's spent nuclear fuel storage facilities contained another 191 tonnes of unextracted plutonium.

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China raises concerns over Japan's nuclear capability

Zhang described Japan as the only non-nuclear signatory to the Nuclear Non-Proliferation Treaty with spent nuclear fuel recycling technology capable of extracting weapons-grade plutonium.

"If Japan has the will and the necessary capabilities, its transformation into a nuclear power no longer looks like a fantasy," he said.

At the same time, Zhang acknowledged Japan's longstanding Three Non-Nuclear Principles, established in 1971. The principles state that Japan will not possess, produce, or allow the introduction of nuclear weapons.

The remarks come amid worsening relations between Beijing and Tokyo and growing Chinese criticism of Japan's expanding defence capabilities.

China has raised the issue before

The plutonium figure is not new to China's recent criticism of Japan.

In March 2026, PLA Daily, the official newspaper of China's People's Liberation Army, also cited the figure of 44.4 tonnes of separated plutonium and said it could theoretically support the production of around 5,500 nuclear warheads.

The report accused Japan of using civilian technology and industrial capacity to build the foundations for a major shift in its defence policy.

It also pointed to Japan's growing investment in advanced military technology, including long-range weapons, missile defence and other defence-related systems.

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Japan's defence expansion draws Chinese scrutiny

PLA Daily argued that Japan's military expansion had moved beyond what Beijing considered a purely defensive posture. It cited increased defence-related contracts involving major Japanese companies, including Mitsubishi Heavy Industries, Kawasaki Heavy Industries, and IHI.

The report also highlighted Japan's cooperation with the US on systems such as F-35A fighter jets and SM-3 Block IIA missiles.

Tensions have intensified as Japan has expanded its defence capabilities and expressed growing concern about China's military activities, particularly around Taiwan. Tokyo, meanwhile, has criticised Beijing over what it describes as a lack of transparency surrounding China's rising defence spending and expanding military capabilities.

What Japan said on nuclear proliferation

In April 2026, at a review conference of the Nuclear Nonproliferation Treaty (NPT) Tomiko Ichikawa, Japan's ambassador to the Conference on Disarmament, rebutted China's claim by saying that "the introduction of nuclear weapons (by Japan) is not permitted" under the three nonnuclear principles.

Ichikawa emphasised that “Japan has been limiting its research, development and use of nuclear energy exclusively for peaceful purposes.”

Japan “will continue to work closely with the international community to realize a world without nuclear weapons” and “will continue to advance realistic and practical efforts to maintain and strengthen the NPT regime,” she said.