about the rad-hard circuits design

hi all
we were counting to do some research on rad-hard circuits design（I am a green man）, I know that the rad-hardness mainly come from the SOI transistor and basic circuit design, but not sure if there are room in architecture design such as error correct or state machine design. Want to talk about it here and get some help. My target is to migrate a MIPS cpu core to rad-hard one