Taking any radiation damage from Krastorio 2, such as handling nuclear materials, results in player radiation damage. The spidertron vehicle is unaffected, and since I'm guess the player entity is not visible, the player does not heal.

Thanks for the report, unfortunately I don't have time currently to make changes to Spidertron Engineer, and I doubt the balance is very good with K2 anyway... anyone is welcome to submit code patches (pull requests) though!

I think if you get out of the vehicle and then eat a fish it might heal you? (You might need to enable a setting to allow getting out of the vehicle though).