Personally I can’t imagine that anyone would want information on nuclear reactors. What would one use that stuff for. It’s not the 50’s, how nuclear reactors work is well known. The limiting factors for building them are probably more about economics and finding manpower and ore not informational.
How often do you need to refuel the reactor? That's inconvenient on land, but in a submarine you need to cut through the pressure hull to access anything and "inconvenient" doesn't even begin to describe it. Modern American reactors are designed to run for 20+ years without refueling for exactly that reason.
How much do you need to run the coolant pumps and how loud are they? A loud sub is a dead sub. If your reactor can run on convection at low power, that's wonderful.
How power dense is the reactor? You need to fit this in a relatively narrow tube, after all! And higher density means higher speed.
How safe is it? How easy is it to cause a meltdown? That directs staffing requirements, and subs don't have staff to spare. A reactor shutting down at the wrong moment can very easily cause the sub to be lost, even out of combat. See the USS Thresher for a demonstration.
And finally, how much maintenance does it need? What portion of this tractor's life needs to be spent tied up alongside a pier having work done, or even worse spent in drydock? The higher the proportion, the more subs you need in order to maintain a given number on station.
So yes, there's PLENTY of things that aren't in a textbook reactor design. And the largest current buyer of nuclear reactors is the US Navy. Number two is the People's Liberation Army Navy.