system
Given the following post, respond as if you're commenting on Reddit:
human
Why isn't it possible to speed up the rate of radioactive decay?
gpt
It is possible in select circumstances.  These are in decays that go by internal conversion.  Since the decay depends on electrons, changes to the electronic environment can change the half life.  This has been seen in numerous isotopes.  U-235m is an example.  

The reason why this is not true for most decays is because the decays depend on characteristics of the nucleus.  It is very hard to change aspects of the nucleus that matters for decay because the energy levels involved are usually in the keV to MeV region.  Those are massive shifts.  That is unlike shifting electronic shells around, which have energies in the eV region.  So intense magnetic or electric fields can easily change the shell structure and thus the rates of electronic decays.