[scajanus]

This (1) suggests that it can perform some metabolism in anaerobic conditions, but not all that it would need to grow/replicate:

"Deinococcus radiodurans is an exceptionally radiation-resistant microorganism capable of surviving acute exposures to ionizing radiation doses of 15,000 Gy and previously described as having a strictly aerobic respiratory metabolism. Under strict anaerobic conditions, D. radiodurans R1 reduced Fe(III)-nitrilotriacetic acid coupled to the oxidation of lactate to CO(2) and acetate but was unable to link this process to growth."

The abstract goes on to describe the metabolism in a bit more detail.

1. https://pubmed.ncbi.nlm.nih.gov/10788374/