> "My point is that it should have been easy to just continue with shipping, as it seems to me that it has to be the default. But maybe I am wrong?"
I don't think it was ever the default for domestic nuclear fuel shipments.
Despite being on the coast, many of the UK nuclear sites do not have easy access to harbours, and the processing facility at Sellafield itself does not have a harbour either: ships carrying foreign nuclear fuel would dock further up the coast at Workington [1].
Since the fuel would be transferred to rail for the final leg to Sellafield anyway, presumably it just made more sense to transport domestic fuel flasks directly via the rail network rather than have a longer, slower, and more complex journey with multiple mode transfers.
It was also likely considered the lower-risk option: train collisions in the UK are very rare (much more rare than shipwrecks!) and the flasks were proven to be able to withstand even the worst-case collision scenario.
In some cases, like at Dungeness for example, old rail infrastructure already existed nearby that could be re-used for a nuclear rail terminal pretty cheaply [2].
I don't think it was ever the default for domestic nuclear fuel shipments.
Despite being on the coast, many of the UK nuclear sites do not have easy access to harbours, and the processing facility at Sellafield itself does not have a harbour either: ships carrying foreign nuclear fuel would dock further up the coast at Workington [1].
Since the fuel would be transferred to rail for the final leg to Sellafield anyway, presumably it just made more sense to transport domestic fuel flasks directly via the rail network rather than have a longer, slower, and more complex journey with multiple mode transfers.
It was also likely considered the lower-risk option: train collisions in the UK are very rare (much more rare than shipwrecks!) and the flasks were proven to be able to withstand even the worst-case collision scenario.
In some cases, like at Dungeness for example, old rail infrastructure already existed nearby that could be re-used for a nuclear rail terminal pretty cheaply [2].
[1] https://cumbriashipphotos.weebly.com/nuclear-carriers.html
[2] https://kentrail.org.uk/dungeness_nuclear_terminal.htm