[Manuel_D]

What does the enrichment of uranium have to do with humans working in proximity? In both low-enriched land based plants and in marine nuclear power plants, the radioactive materials are contained in the pressure vessel and inner cooling loop.

[15155]

HEU results in fewer actinide products and a substantially more-compact reactor.

[crote]

So in other words: a non-naval SMR which doesn't use HEU is going to be substantially larger - which would make it substantially more expensive, and therefore not representative of civilian SMRs?

[15155]

Who said anything about expense? Why does "bigger" equal "more expensive?" Lead, concrete, etc. are cheap on land, but volume is a precious resource on a ship. HEU isn't the only reactor fuel out there, either.

And of course, all non-naval reactors are naturally going to be larger: they aren't surrounded by a practically-infinite fluid heatsink.