This is correct. See my comment downthread about the Rankine cycle. As well as a source of heat, for efficient electricity generation you also need a source of "coolth".

The reactor is helium cooled. Their own collateral (https://usnc.com/mmr-energy-system/ ; annoying scrolljacking) shows shipping the heat to e.g. industrial process use or electricity generation - but for generation, you'll need a standard steam turbine + condenser setup. Which consumes water for cooling the condenser.

Also from their web page:

> FCM® fuel cannot be re-processed using currently available reprocessing schemes.

They list this as a nonproliferation benefit, but it has downsides.