The US had the nuclear-powered cargo ship NS Savannah launched in 1959.
The Russian Sevmorput is the world's only civilian nuclear-powered cargo ship. It was commissioned in 1988. It is being used to deliver about 20,000 tons of cargo to mainly Antarctic routes.
A nuclear ship is about 50% faster than a diesel ship. A three-week run from China to the US would be completed in two weeks.
There has been progress to small modular nuclear reactors. The NuScale 76 MWe reactor could be built for about $250 million. This could be adapted for nuclear ships. The price would work out because there would be almost no operational costs without the purchase of diesel. Annual operating costs for a commercial ship are about $40 million per year.