China's nuclear-powered box ship project moves forward

China’s initial claim that it was developing a thorium-based molten-salt nuclear reactor-driven box ship has been followed by the reveal of more specific details.

China State Shipbuilding Corp’s (CSSC) Jiangnan Shipyards unveiled the initial 24,000-TEU box ship design at the Marintec China maritime exhibition in Shanghai in December 2023.

The original 24,000-TEU box ship design has become smaller, at 14,000 TEU, according to the latest reports from the Chinese press. 

English-language paper the South China Morning Post noted, “What makes this ship truly groundbreaking is that it will be powered by a thorium-based molten salt reactor (MSR) with a thermal output of 200 MW – matching the power level of the S6W pressurised water reactor used in the US Navy’s most advanced Seawolf-class nuclear attack submarines.”

Thorium, an abundant, naturally occurring metal is a clean, efficient fuel with extraordinary energy density. One tonne of it produces the same energy as 3.5M tonnes of coal. Its byproducts are significantly safer than uranium (in that plutonium is not produced under fission) and, with shorter half-lives, degrade far faster. It does not need to be enriched and is not difficult to access. It is also a completely zero-emissions fuel, and reports have shown that China has large reserves of thorium. 

“The ultra-large nuclear container ship is designed to truly achieve zero emissions during the ship’s operating cycle,” China State Shipbuilding Corp said on Weibo, back in 2023 when the project was first announced.

Proponents of MSRs say the reactors are safe, efficient and operationally proven solutions. They work by dissolving thorium in liquid salt. The ensuing chain reaction heats the salt, producing steam to drive a turbine and create electricity. Although developments of MSRs on land are well documented, its potential for delivering clean maritime power is still untested in real-world scenarios.

Speaking about the suitability of thorium MSRs as an energy source for maritime applications, Norwegian University of Science and Technology professor Jan Emblemsvåg, an expert in the field of thorium and nuclear power generation, noted, “MSRs have enormous potential for enabling clean shipping. There is so much uncertainty over future fuels, but here we have an abundant energy source that, with the right approach, can be safe, much more efficient, cheaper, and with a smaller environmental footprint than any existing alternative.  From my perspective I see this as the most viable, and potentially the only credible solution for a zero-emissions fleet that can operate under commercial terms and cost levels."