Graphite brick, one of ten graphite components manufactured by Southern Graphite Services (SGS) in 1982 for a life-size simulation of the core of an Advanced Gas-cooled Reactor. These consist of three types core bricks, three sorts of connecting piece, infill pieces, side wall bricks and convertor pieces between the wall and the core. The graphite bricks in the reactor core and act as a moderator to control the chain reaction by slowing down the neutrons.