Thanks for the link, it's an interesting read.

It definitely seems like the big challenge for MSRs is of the materials/chemical engineering variety. I guess some of these could be designed around: for instance I've heard Kirk Sorensen (LFTR advocate) suggest situating the entire reactor and plumbing complex in a drain/basin of sorts. In the case of a pipe break the fuel(s) simply drains in to a passively cooled storage tank (deep underground).

Also some of the chemical handling would require great care. Fluorine, for instance, is not something I'd want to mess around with...