Nuclear Chemistry
Fission Reactors
Nuclear Waste
Gas-Cooled Reactor


Gas-cooled Reactor (AGR)

This type of reactor is used mainly in the UK. It was developed from another gas-cooled reactor, the Magnox reactor, a number of which are still operating there.


Figure 4 (Courtesy of the World Nuclear Association)

The Advanced Gas-cooled Reactors, like the Magnox reactors before them, use graphite as a moderator and carbon dioxide as a coolant. This differs from the previous reactors where water was used as both moderator and coolant.

The AGR uses enriched uranium oxide pellets (2.5-3.5%) in stainless steel tubes for fuel rods, and control rods penetrate the graphite moderator. The carbon dioxide coolant circulates through the reactor core at temperatures up to 650C. The steam generator tubes run inside the reactor core, keeping the water separate from the carbon dioxide coolant, but keeping the steam in the tubes heated to turn the turbine.

A secondary shutdown system involves injecting nitrogen to the coolant.


Written and created by Cami Idzerda. Last updated 11/29/2001. 

Email: CIdzerda@aol.com