3. PWR fuel design

A few vocabulary reminders

In a light-water reactor fuel, fissile material takes the form of small sintered uranium oxide cylinders known as "pellets". A number of these pellets are stacked in a tube – known as a cladding tube or sheath – sealed at both ends by welded plugs to isolate the fissile material from the outside environment; this assembly forms what is known as a fuel rod. The fuel rods are assembled into a bundle – known as a fuel assembly or fuel element – by insertion into a skeleton structure – (see figure 3 ) – fitted with end pieces (top and bottom end pieces or head and foot) to enable the...