It's a 1MW reactor. That's a thousand times smaller than conventional nuclear reactors. It doesn't seem unlikely that it could be passively cooled.
For the rest, a great source is the book Plentiful Energy, by the chief scientists of another small fast-reactor project at Argonne. For that reactor, the fuel is a mix of plutonium isotopes which can't be used for bombs and are much more difficult to purify than natural uranium ore. The waste goes back to the radioactivity of the original ore in a couple centuries.
