"The principle is that the nuclear radiation splits the water atoms which results in energy. "
I'm going to call BS. To my knowledge, neither alpha, beta OR gamma rays can split water molecules (not atoms), and if they did, it wouldn't "result in energy". (You also wouldn't want beta or gamma rays ANYWHERE near your gonads.) MAYBE you could separate the hydrogen and oxygen atoms, and then run the hydrogen through a fuel cell, but we still have the problem of the "nuclear radiation" splitting the water in the first place.
It's baloney.