If you do have the Spacemaster books, if memory serves, any edition will do as they all have a Radiation Critical Table in them. At least I think they do. I do know the SMP book "Blaster Law" does.
If not, then I have used the Nether tables from the original Elemental Companion. Plasma also worked rather well.
If have the current EC, then the AEther and/or Nether tables will work.
RoCo3 also has Plasma and Disruption critical tables which I have used to substitute for Radiation.
Otherwise, I am at a loss since using my memory at school. Hope helps.
rmfr