A 1930s nuclear capital-ship counterfactual

How would capital ships change if practical naval reactors appeared in 1930?

They could gain enormous speed and endurance by replacing boilers and fuel, but would need heavy shielding, cooling, and new machinery arrangements.

The counterfactual makes workable naval fission reactors available around 1930 or 1931. Battleships and carriers could trade boilers and fuel bunkers for reactors and powerful steam turbines, producing exceptional endurance and perhaps speeds above forty knots. Cruisers would be harder to convert because their smaller hulls leave less room for machinery, shielding, and structural protection. Concrete shielding or armour would consume some of the space and weight saved by removing conventional plant. Nelson and Rodney are suggested as plausible retrofit candidates because their arrangement could release substantial machinery and fuel volume. The scenario highlights that nuclear propulsion does not make engineering constraints disappear; it exchanges fuel logistics for reactor mass, shielding, cooling, and specialized support.