China has made significant advancements in nuclear fission technology, developing a compact and powerful nuclear reactor system that could revolutionize interplanetary travel. In a paper published in the peer-reviewed journal Scientia Sinica Technologica, scientists from the Chinese Academy of Sciences detail their innovative design that surpasses NASA’s rival system and promises to shrink a megawatt-class reactor to an unprecedented size.
What sets the Chinese nuclear reactor system apart is its compactness, ease of launch, and longevity. Once operational in space, the 1.5-megawatt reactor and its heat sink will reach the height of a 20-storey building. However, on the ground, they can be folded into a container-sized space weighing less than eight tonnes. Led by Wu Yican from the academy, the researchers emphasize that this design makes it “easy to load and launch by rocket.” Additionally, the system is capable of sustaining stable operations for extended durations in challenging space environments.
The powerful energy source provided by the nuclear reactor will enable high-mass, round-trip transportation for both crewed and cargo space flights. Compared to SpaceX’s methane-fueled Starship, the Chinese system offers a significant time advantage. A round trip between Earth and Mars could be completed in just three months using the nuclear-powered spacecraft, while estimates suggest the Starship may require at least seven months to reach Mars even for a one-way journey.
So how does this innovative nuclear reactor system work? By fissioning uranium fuel, temperatures of up to 1,276 degrees Celsius (2,328.8 Fahrenheit) can be achieved. This intense heat causes helium and xenon, in their liquid forms, to expand into gases, propelling a generator. The resulting chain reaction generates fast neutrons, ensuring an efficient and uninterrupted power supply for at least 10 years. The use of liquid lithium further enhances the compactness of the reactor due to its high thermal conductivity and lightweight properties.
Successful ground tests have demonstrated the viability of integrating a lithium-based cooling system with a Brayton generator. Traditionally, reactor designs require considerable space for a heat exchanger and radiation shield. However, Wu and his team have developed a technology that merges these two components into a single unit, reducing the overall size of the reactor.
Looking ahead, the Chinese space exploration program will focus on ensuring the safety of nuclear reactors during launch and operation phases. It is crucial to eliminate the risk of a nuclear explosion, even in the event of a reactor falling back to Earth. Additionally, the project team plans to incorporate artificial intelligence in the long-term unmanned operation of space reactors. This technology will enable autonomous diagnosis and resolution of any malfunctions or faults that may occur.
China’s ambitions for space exploration are grand. They plan to embark on missions such as manned lunar exploration, asteroid exploration, flying by Jupiter, and exploring the edges of the solar system. According to Wu and his team, space reactors will be crucial in these endeavors. As they continue their research and development efforts, China is poised to take the lead in interplanetary travel with their groundbreaking nuclear reactor system.
