Technetium-99

Production
Technetium-99 can be extracted from depleted Uranium from the generic reactors. Can also be obtained from depleted Plutonium and MOX fuel via a ZIRNOX reactor or a Research Reactor.

Technetium-99 makes up 20% of non-depleted Uranium-235-type Short-Lived Nuclear Waste from the RBMK.

Uses
It currently can be used to make Technetium Steel, a extremely corrosion resistant metal, and self-charging batteries that produce 100 (Plutonium-238 Battery) and 500 (Polonium-210 Battery) HE/tick.

Trivia

 * It has a half-life of 211,000 years, making it only mildly radioactive IRL.
 * Its fully ionized isotope sibling Technetium-97 is stable.
 * IRL it is considered a long-lived nuclear waste product, not a short lived one.
 * IRL it also has potential uses for strong catalysts and nanoscale atomic batteries (presumably Betavoltaic, due to it being primarily a beta emitter).
 * Technetium is a transition metal that is special because it is the lightest element to have no stable isotopes.