As much as we want the next generation ships with less CO2 emissions, that nuclear cargo ship is not coming anytime soon. It will use a Thorium melting salt reactor, which although not new, is still in experiment. US first proposed melting salt reactor in the 1940s and had operated one briefly in the 1960s. China is building and testing an experimental Thorium reactor. It made the news earlier this month for been successfully converting Thorium to Uranium, perhaps means it is actually burning Thorium as compare to rely on Uranium in previous melting salt reactors. The news also states the plan has 3 stages: experimental reactor, research reactor, and demonstration reactor. The current one is at first stage. The third stage, demonstrator reactor, is scheduled to build in 2035. Therefor that nuclear cargo ship is at least another 10 years from now.