Re: Russia
Russia has built a series of fast metal-cooled reactors, the BN-family over the past fifty years or so. The current new kid on the block is the sodium-cooled BN-800 which started up a couple of years ago. It is capable of burning spent fuel, destroying waste isotopes from reprocessing, using up weapons-grade plutonium etc. but it's still experimental with new kinds of solid-metal fuel structures needing developing and testing before it can do all the things it's supposed to be able to do. It's very much experimental, they're not going to be building lots of them in a hurry. Instead they're churning out VVER-1200 pressurised-water reactors very similar to the ones that failed at Fukushima. They claim the new pressure vessels for the VVER-series reactors can be licenced to operate for a century in service due to new manufacturing and testing techniques, and pretty much everything else in a reactor can be replaced during scheduled servicing and upgrade operations.
As for the barge-mounted reactor concept they're building a couple of these to be used in northern waters to provide power to remote communities. They're using existing KLT-40S ship reactors, the sort that power their big nuclear icebreakers. They're small conventional PWR designs, not thorium or travelling-wave or anything the PowerPoint Cowboys have a hard on for. The main use for these barge-mounted reactors will be to make oil and gas exploration in the Arctic a bit easier by powering the onshore facilities, ports etc. The Chinese are also investigating this idea, in part to power the offshore islands/unsinkable aircraft carriers they're building in the Spratlys.
Lead-bismuth cooled reactors were a design used in some Soviet nuclear subs. I understand they were not a technical success with some problems in controlling the reaction in various operating modes -- ship and sub reactor output levels get swung from low-power to high-power a lot and that makes for tricky nuclear chemistry in some situations (Xe-135 poisoning of the fission process, for example).
Biting the hand that feeds IT
