Right. A nuclear reactor generates massive amounts of heat from fission, then uses that heat to boil water (sometimes heavy water for better radiation shielding

Right. A nuclear reactor generates massive amounts of heat from fission, then uses that heat to boil water (sometimes heavy water for better radiation shielding) to make steam to cause turbines to spin, which generates the electricity. (in fact, fossil fuel burning plants also use this steam-electric model) If the end goal is to generate heat, then there's no good reason to add those additional steps.