Actually steam turbine produced more hp in some case than nuclear. Check out USS kitty hawk. Don't have the idea if it's non nuclear , the power will have deficiency problem.
The only advantage nuclear has over conventional is non refuelling,
Charles de Gaulle is a great example nuclear means nothing. Which is precisely I bring this up. It can never power a electric catapult with that nuclear power plant. It even has problem going at 25 knots and u think it will have enough power for electric catapult?
If China can land Rover on Mars. Surely, everything for the new aircraft carrier 2021 is well thought in all department including power output and full steam speed, high intense operation. The worry is overdone.
The worry shall be on USS Gerald Ford. This aircraft carrier brag as if some alien technology which until now still non combat ready. After more than 4 years commissioned.
Maybe the reason why China goes steam turbine for this new electric catapult aircraft carrier.