Hiroshima University researchers found that using Ultraviolet C light with a wavelength of 222 nanometers which is safer to use around humans effectively kills SARS-CoV-2
A wavelength of 222 nm UVC cannot penetrate the outer, non-living layer of the human eye and skin so it won't cause harm to the living cells beneath.
https://scitechdaily.com/first-proof-that-a-safer-uv-light-effectively-kills-covid-19-virus/
They probably know more about radiation safety than just about anyone.