Spot on, and from my recent understanding, Pratt indirect cycle was to do exactly that with 4 x J58s - also known as JT-11s, hence the name: JTN-11. Those four J58s would get a liquid metal reactor loop inside their combustion chambers. The whole thing called NJ-18A.Most likely?
Picture a jet engine. Replace the combustion chamber with the reactor or at least the reactor cooling loop. Reactor heats air, which expands and drives a turbine (and produces thrust), the turbine spins a compressor to stuff more air in the front and make more thrust. That's a nuclear turbojet in a nutshell.
So this brings an interesting question. The Soviets once created the Alfa submarines with liquid metal reactors. Does Burevestnik use that past experience to pull a small, indirect cycle ? a liquid metal reactor as the heart of a jet engine ?