In the icebreakers each reactor heats water into steam, the steam spins turbo-generators, and electric motors turn the propellers. Most of the heat never reaches the water: between a tenth and a fifth of the reactors' thermal megawatts comes out at the shafts.
Level ice each class is rated to break, beside a person 1.8 m tall. Project 10510 is meant to go through 4 m.
Reactors and shaft power from Wikipedia (Lenin: Russian article, 32.4 MW / 44,000 hp; Arktika class 55.3 MW; Taymyr 3 × 12 MW motors; Project 22220 60 MW; Project 10510 120 MW; Sevmorput 29,420 kW). Ice ratings from the same articles; Arktika class is given as 2–3 m, Lenin has none. Refuelling intervals: World Nuclear Association, Nuclear-Powered Ships (OK-900A, RITM-400); Wikipedia, Project 22220 (RITM-200).