1. General description of an AGR power plant

In the 1950s, Great Britain embarked on the development of power reactors. The concepts developed were directly influenced by the country's knowledge of nuclear physics, industrial capabilities and know-how. Initially, the reactors commissioned were thermal neutron reactors using graphite-moderated, gas-cooled, continuous-load natural uranium metal fuel: this was the MAGNOX (MAGnesium clad Non OXyde fuel) line, whose French counterpart is the UNGG (Uranium Naturel, Graphite, Gaz) line. The MAGNOX and UNGG lines are now in the dismantling phase.

The objective of making the gas sector more competitive involves increasing unit power and power density. The quest to increase the unit power of the graphite-gas solution initially focused on the general architecture of the reactors, and led to major changes in the design...