Alright, getting back to the whole thing about nuclear power...there is an incredible amount of energy in the form of the bonds between the particles in an atomic nucleus — it's what prevents the positively charged protons from repelling one another. Breaking those bonds causes bits of the atom to fly off: alpha particles, which are He2+ nuclei; beta particles, which are leptons (e.g. electrons); and gamma particles, which are high-energy photons. These smash into more atoms, causing a chain reaction. In a fission reactor, all of these high-energy particles bump into water molecules, giving them kinetic energy and creating steam, which spins a turbine. I think you're on board with that last part. So what part of this don't you agree with?
Also if you disagree with relativity I would like you to come up with an alternative explanation for gravitational lensing, which we can readily observe.