A, the nuclear energy used by the aircraft carrier is controllable nuclear energy, which is produced by heavy nuclear fission. Nuclear energy is a new energy source, so yes;

B, nuclear energy, coal and oil can't be obtained from nature in a short time, and they all belong to non-renewable energy. So, it is correct.

C, the carrier floats on the sea surface, and the buoyancy is equal to the gravity of the carrier itself. When flying away from some aircraft, the gravity of the carrier decreases and the buoyancy decreases. According to Archimedes' principle, F float = ρ liquid V row G, when the density of seawater is constant, its buoyancy decreases, the volume of discharged seawater decreases, and the carrier floats a little, so it is wrong;

D radar finds enemy military targets by transmitting and receiving electromagnetic waves, so it is correct.

So the answer is: ABD ..