And I'm to assume that decay events are like a fundamental law of physics in that they will never change, so they cant be speeded up, or slowed down, or even reversed?
tl;dr: it's more trouble than it's worth, since you need radioactive materials as the neutrons sources, and stray neutrons tend to bump into other matter and cause yet more radioactive waste.
I get the impression that your understanding of the current state of particle physics is approximately 80 years behind the state of the art. You're catching up with Leo Szilard's ideas in the 1930s
Decay, like anything else can be (from our subjective point of view) be slowed down by accelerating it away from us at speeds approaching that of light.
As far as the parent comment's implied question, "and is that useful for radioactive waste disposal?" the answer is a strong "no, there are far better uses for the energy required, within and outside of radioactive waste disposal", including using this energy instead of energy from the nuclear reactor that makes waste.
An atomic bomb is when you convince a lot of Uranium-235 or Plutonium to decay all at once in an uncontrolled way.
A nuclear reactor is what happens when you convince material to decay at a controllable rate.
It's way more complex than that but you can look up the rest, e.g. "Nuclear chain reaction".
Where I think you're going with this is
https://physics.stackexchange.com/questions/594598/destroyin...
tl;dr: it's more trouble than it's worth, since you need radioactive materials as the neutrons sources, and stray neutrons tend to bump into other matter and cause yet more radioactive waste.