What magical property does lithium have that makes reactors safer? There are experimental fast reactors around the world and they use sodium as a coolant (the moderating effect of water or carbon is undersirable in a fast reactor). There was a very serious accident at the Japanese fast reactor when a coolant pipe leaked. Hot sodium reacts vigorously with air generating a lot of heat and fine radioactive dust. Pouring water on burning sodium or lithium doesn't help much, either.

The idea of helium is that it's extremely inert, so there's no possibility of any undesirable chemical reactions. Graphite spheres could well be safer than metallic fuel as the melting point of graphite is extremely high. They're fretting about the possibility of a graphite fire, but obviously air would have to enter the reactor for that to happen and the fire could be put out by flooding the reactor with any inert gas - presumably they'd have plenty of helium on hand, but nitrogen, CO2 etc would work just as well.

Presumably a containment is not required because the reactor doesn't operate at the very high pressures used in water-cooled reactors, but given that any nuclear facility has clear attractions for terrorism, perhaps some kind of defensive structure might be prudent.

I'm not sure about the idea of running turbines directly from the cooling circuit, infact one wonders if ABC quite understood that. The reason one raises steam in a secondary cooling circuit is so that all the radioactive material (an some of the radioactive fission products are gases) remains inside the reactor building. The secondary circuit remains clean, so all the turbines etc can be worked on without involving radiological issues.

One can't help but feel that nuclear power still has a long way to go before any new plant is likely to receive funding and legal approval.

As I understand it, lithum coolant also acts like a sealant when exposed to air. Therefore such cooling systems are essentially invulnerable to "pinhole" leaks slowly drawing down the coolant level.

Also, and this is even more vague, I believe the lithum designs have few, if any, moving parts, further simplifying the system.

This is all from memory of old slashdot discussions, so it's probably wrong. I'll do some research and see what comes up.