> The radiation is continuously creating isotopes in the gases in that air. What radiation? Note that he didn't say he received radiation exposure throughout t

> The radiation is continuously creating isotopes in the gases in that air. What radiation? Note that he didn't say he received radiation exposure throughout the submarine, only "working on the reactor". That's an isolated space that doesn't continuously exchange air with the rest of the submarine and has an extra layer of shielding between it and the rest of the submarine (in addition to the shielding around the reactor itself that separates that from the space where people working on the reactor go--nobody ever goes inside the reactor itself).