Here's a large (35 inches) cutaway drawing of a Magnox reactor, which gives some visual scale to the monster that is a gas-cooled reactor: (PDF) http://econten

Here's a large (35 inches) cutaway drawing of a Magnox reactor, which gives some visual scale to the monster that is a gas-cooled reactor: (PDF) http://econtent.unm.edu/cgi-bin/showfile.exe?CISOROOT=/nuceng&CISOPTR=47&filename=42.pdf http://econtent.unm.edu/cgi-bin/showfile.exe?CISOROOT=/nucen... (Note this isn't the AGR that Stross depicts, but its predecessor the Magnox). For size reference, the six boilers are 118 feet tall by 18 feet diameter (36m * 5.5m); the building is 170 feet high (52 m).