If scientists are wrong about Earth's age based on radioactive material and the decay rates are really much faster, how would nuclear power plants be affected?

Nuclear power plants use the energy originating from the splitting or uranium atoms to produce steam, which in turn drives a turbine generator.

The main problem with this form of energy production is the byproduct from the nuclear reactors known as radioactive waste. Although it is no longer efficient for the energy production, this waste is still radiating large amounts of heat and radiation. Thus, they are very hazardous as they are fatal on direct exposure and can contaminate the environment.

Due to the extremely long half-life, long term storage for this waste is extremely problematic. However, if the decay rates were much faster, then the half-life would also be much shorter. Thus, short term storage solutions could be found.

Excepting the nuclear waste and the potential accidents (which are minimized in modern plants), nuclear energy does not immediately affect the climate on earth. With short half-lives, nuclear energy would perhaps become more popular than solar or wind energy as it is more reliable and efficient.