I note that the site I sent to you didn't open with the full info. Here is a quote from it:
Two air-cooled, graphite-moderated Windscale reactors constituted the first British weapons grade plutonium 239 production facility, built for the British nuclear weapons program in the late 40s and the 50s.
Windscale was also the site of the prototype British Advanced gas-cooled reactor.
On the original I am able to click on to the 'Advanced gas-cooled reactor' and when I do it reads as follows:
An Advanced Gas Cooled Reactor (AGR) is a type of nuclear reactor. These are the second generation of British gas-cooled reactors, using graphite as the neutron moderator and carbon dioxide as coolant.
I argued re air saying it wasn't a gas, but the dictionary proved me wrong.
Not trying to make your choice more difficult, but wanted you to see the portion of the article which you didn't receive in full.
Cheers O-ice
PS. The underlining is mine.