Nuclear power is actually very safe and environmentally friendly. We should use it more and keep improving our reactors.
Coal is worse than Nuclear, both in total human deaths through environmental pollution as well as in miner deaths, as well as in radiation-related deaths, as well as in CO2 generation, which might kill all humans via climate change.
While Nuclear is a rather safe source of energy, better methods exist today which we should be focusing on. The time needed improving Nuclear to produce more power more safely can be better spent on further developing technologies such as wind and solar which are already safer and more available.