The idea that you can actually 'disinfect' something in the real world, outside of a cleanroom or high end operating room, for more than a few minutes to hours is mostly a polite fiction. Any sort of real world plumbing arrangment is going to be hosting assorted biofilms and other incredibly durable bacterial reservoirs more or less inevitably. As the massive success of modern sanitation systems has proven, you can get water 'clean enough' for the more-or-less-healthy to stay that way; but if you actually need to exterminate almost all the bacteria, you are picking a whole different fight.
If, though, you only need to ensure that the contents of the droplets emitted by the cooling system in operation are reasonably disinfected, intense UV in the outflow ducts might be able to do that, and UV isn't high energy enough to do too much violence to metal parts(plastics/rubber/etc. can be trouble; but you won't be commiserating with nuclear reactor operators over radiation embrittlement issues.)