Nuclear submarines could be a template for nuclear-powered spacecraft:

Space Nuclear Propulsion - https://www.nasa.gov/space-technology-mission-directorate/td...

Submarine vs Submersible vs Spacecraft (2025) - https://braindrippings.substack.com/p/submarine-vs-submersib...

The Spacecraft and the Submarine (2008) - https://www.thespacereview.com/article/1202/1

South Korea should build nuclear cargo ships. It’d be great for the environment.