Making it smaller does add physics based safety features that couldn't be achieved otherwise.
At best the worst case downside is limited, but so to is the amount of power generated.
"Stationary Low-Power Reactor Number One, also known as SL-1 or the Argonne Low Power Reactor (ALPR), was a United States Army experimental nuclear reactor in the western United States at the National Reactor Testing Station (NRTS), later the Idaho National Laboratory, west of Idaho Falls, Idaho. It experienced a steam explosion on the night of January 3, 1961, killing all three of its young military operators, and pinning one of them to the ceiling of the facility with a reactor vessel plug. The event is the only reactor accident in U.S. history that resulted in immediate fatalities.
(I don't know enough about this to know if nuclear will have a large impact, in the grand scheme).
If the reward is high enough the risk might be justified. Personally I doubt it (mostly because economically solar + wind + power storage seems like a better bet), but that's a whole other discussion.