Assistant Secretary of Defense John Plumb testifies before the House Armed Services Committee in Washington, DC, March 30, 2023. Photo: DOD / EJ Hersom

The US Department of Defense and numerous private commentators allege that Russian-Chinese cooperation on fast breeder reactors will provide plutonium for large numbers of Chinese nuclear weapons. Assistant Secretary of Defense John Plumb told Congressional hearings on March 8:

“It’s very troubling to see Russia and China cooperating on this. They may have talking points around it, but there’s no getting around the fact that breeder reactors are plutonium, and plutonium is for weapons. So I think the [Defense] Department is concerned. And of course, it matches our concerns about China’s increased expansion of its nuclear forces as well, because you need more plutonium for more weapons.”

The Pentagon knows better than this. Anyone conversant with fast breeder reactor technology is aware that the type of plutonium that can be produced in such reactors is much less suitable for nuclear weapons than the plutonium produced in other reactor types, whose design and construction China has long mastered.

It is therefore nonsensical to charge that the main goal of the Chinese fast breeder program is weapons-related. Rather, the motivation for the program is consistent with that of other nations that have pursued fast breeder reactor designs, including greater efficiency in the utilization of nuclear fuel, reduction in the amount and toxicity of nuclear waste and greater independence from outside fuel supplies.

Here are the details, point by point. They speak for themselves:

1.) Although fast breeder reactors have been around since the 1950s, practically the entirety of the plutonium employed in nuclear weapons in the world so far has been produced in dedicated military facilities by reactors of a completely different type – graphite-moderated or heavy-water-moderated reactors. These specialized military plutonium-production reactors operate with “slow” neutrons as opposed to the “fast”, high-energy neutrons involved in fast breeder reactors. (The graphite or heavy water is used to slow down – “moderate” – the neutrons produced in fission reactions, thereby increasing the probability of their absorption by other nuclei.)

In the US, for example, the plutonium used for thousands of nuclear weapons was supplied by graphite-moderated reactors at the Hanford facility and heavy-water-moderated reactors at the Savannah River facility. There are good technical and other reasons why other reactor types – all of which produce plutonium to a greater or lesser extent – have not been used in weapons production.

2.) China is quite familiar with the technology of military plutonium-production reactors, which it has used since the early days of its nuclear weapons program. If it so desired, China would have no difficulty whatsoever to rapidly expand its capacity to supply plutonium for nuclear weapons using dedicated graphite, or heavy-water-moderated plutonium-production reactors, which (relatively speaking) are far simpler, cheaper and faster to build and operate than the fast breeder reactors projected for China’s civilian nuclear power program. In case China would decide to produce thousands of nuclear weapons, it will not need help from Russia or anyone else, nor would it need breeder reactors.

3.) In fact, fast breeder reactors of the sort China is building are very poorly suited as potential sources of plutonium for nuclear weapons. The Pentagon and US Congress-circulated scare stories emphasize that large fast breeder reactors produce large amounts of plutonium. That is true, but plutonium produced in fast breeders cannot be used for nuclear weapons without cumbersome and costly processing. The plutonium generated in the relevant fission reactions is a mixture of the isotopes Pu-239 and Pu-240.

The core of the Russian Fast Breeder Reactor on June 27, 2017 in Zarechny, Svedlovsk Oblast, Russia. Image: Getty

Because of its specific properties, the presence of more than a tiny amount of Pu-240 renders the material unsuitable (or at least highly disadvantageous) for use in militarily viable nuclear weapons. As Pu-240 accumulates increasingly during operation, it would be necessary to remove fuel elements from the reactor prematurely after a short time – a procedure which would be totally contrary to the design and operation of fast breeder reactors such as those in China’s program, which are built to achieve a high “burn-up” of fuel.

Theoretically, this procedure is not absolutely impossible, but such a practice would be exorbitantly costly compared to a dedicated facility based on graphite- or heavy-water-moderated reactor technology.

    4.) For these and other reasons, and given China’s well-established option to use dedicated military plutonium-producing facilities, it would be irrational for China – or any other nation – to utilize fast breeder reactors as the basis for a strategically-relevant expansion of weapons plutonium production.

    5.) Russia, presently the world’s leader in fast breeder reactor technology and strategic partner for China’s fast breeder reactor program, has been operating large fast breeder reactors for many decades. But there is no evidence that Russia (or the former Soviet Union) ever used these reactors for military plutonium production. Ironically, since the end of the Cold War, Russia has used its fast breeder reactors to “burn up” plutonium from nuclear weapons, in the context of weapons reduction agreements with the US.

    6.) All in all, there is no reason to doubt that the fast breeder reactor program in China has goals other than those that motivated fast breeder reactor development around the world. These include, most notably, achieving a “closed” fuel cycle, increasing by a factor of 100 the amount of energy that can be extracted from uranium, and creating a basis for fission reactors to potentially supply the world’s energy needs for hundreds or even thousands of years. At the same time, the fast breeders can provide an effective means for “burning up” waste products from nuclear power plants.

    7.) The disinformation about China’s fast breeders offered by the Pentagon and others misses the key point: China and Russia are poised to dominate the world’s entire nuclear power sector, while the US and other Western countries have for decades been downsizing and even dismantling their nuclear industries.

    China is currently pursuing by far the world’s largest nuclear power program, including the most innovative reactor types. Russia, the world’s leader in fast breeder reactors and a number of other key areas of nuclear technology, is today by far the world’s largest exporter of nuclear power plants and has a nearly dominant position in many global nuclear supply chains.

    Russia’s state nuclear corporation Rosatom is currently involved in the construction nuclear power plants in China. Photo: AFP / Sputnik / Rosatom.

    Together, China and Russia are set to capture the vast emerging market for nuclear power in developing countries – a circumstance of great strategic importance. Russia’s nuclear exports are booming, and China already has plans to build and finance approximately 30 nuclear reactors in Asia, the Middle East and Africa as part of its Belt and Road Initiative.

    This is only the beginning and that is the real cause for panic in Washington. The scaremongering about fast breeders and nuclear weapons is clearly intended to prepare the way for severe sanctions designed to cripple Russia-China nuclear cooperation efforts, particularly of the Russian nuclear company Rosatom and Chinese companies cooperating with it.

    But Russian and Chinese commitment to the technology is firm, and sanctions are highly unlikely to derail the project.