The Magnox Natural Uranium Graphite-Moderated Reactor

The Magnox Natural Uranium Graphite-Moderated Reactor 

The general design features of the magnox line of reactors will be illustrated by describing the last of the series to be constructed in the United Kingdom, the twin-reactor 1180-MWe station at Wylfa Head, North Wales. The Wylfa station commenced generation in January 1971. 

Core outlet temperature (°C) Average power density (MW m ) 

The internal surface of the pressure vessel is protected by a steel liner of 19-mm thickness, which also serves as a gas-tight containment for the reactor. Numerous cooling water pipes are welded to the external surface of the liner for heat removal purposes. Neutron and y shielding for the boilers is supplied by a pair of concentric steel tanks, with the interspace between them filled with steel plates and carbon blocks. 

The core and its associated shielding rest on a radial grid which is supported on rollers on the pressure vessel. The natural uranium fuel elements are located in vertical channels in a structure of graphite blocks 17.4 m in diameter by 9.2 m high. The channels are arranged on a square 

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