Sadly the best thing we (as a human society) can do after a nuclear disaster is damage limitation, for the environment, for wildlife, and for the surrounding human population.
Scientists should always look for newer, cleaner and safer sources of energy. 100 years ago we didn't know about nuclear power, so what sorts of things still remain to be discovered?
Sadly, research into these new sources of power is being stifled because of a lack of finance.
Wind, solar and wave power are in abundance, but can be unreliable, but the collection technology is improving in efficiency.
Nuclear power is marginally safer than it was in 1985, but it won't be completely safe until all of the nuclear reactors have been shut down and replaced by something safer.