Nuclear trains

Early in the nuclear age, that was banned by treaty agreements. It is not legal to intentionally put nuclear waste into the ocean.

If the core is melting down, I can assure that it will be towed out and a decision will be made on what to do with it. Every effort will be made to combat the casualty in port, because once towing begins, all water and electrical services go away and onboard reserves are limited. If the sub is to be towed due to a nuclear accident, it’s not ever going to be operational again.

The ship will also be sealed as well as it can be, so I wouldn’t consider it intentional dumping of nuclear waste. It’s not waste.

My point is that you can move a boat away from the people and things. It’s a lot harder to do that with rail.