Fusion gives more energy than fission right? When a uranium nucleus fissions into two daughter nuclei fragments, an energy of ~200 MeV is released. Whereas in a fusion of deuterium to give helium atom, only 18.3 MeV is released (which is the maximum?). Yes, the nucleus of uranium are heavier but the same deuterium fusion occurs in the stars and gives off a much larger amount of energy.
If we consider energy released per reaction (fission or fusion), energy released is more in the case of fission.
If we consider energy released per unit mass (say one kg Uranium and 1 kg hydrogen), the energy released in fusion is very much larger than in the case of fission.
In fusion about 4 amu releases approx 20 MeV whereas in fusion about 236 amu releases approx 200 MeV