Deuterium monoxide

Water whose hydrogen atoms are all deuterium isotopes

Heavy-water pressurised reactor

Primary heat transport: D2O (heavy) water

High-temperature gas-cooled reactor

Primary heat transport: helium gas

High temperature gas cooled reactor

Fuel assembly arrangement in hexagon form

HTGR fuel element form consisting of movable spherical elements

The fuel elements of tennis-ball size are called pebbles

HTGR fuel element form consisting of prismatic blocks

Primary heat transport: helium gas

High-temperature gas-cooled fast reactor

Primary heat transport: helium gas

HTGR fuel element form consisting of movable spherical elements

The fuel elements of tennis-ball size are called pebbles

In operation is a plant or unit with a valid operation licence in any operating state from a cold shut-down and maintenance to full-power operation

BWR with primary cooling loops in same vessel

Core, primary loop, steam generator in the same vessel

PWR with primary cooling loops in same vessel

Core, primary loop, steam generator in the same vessel

'Large' size

Electric output of between 200 MWe and 300 MWe (or more)

Low enriched uranium

Uranium enriched to less than 5 percent U-235

Deuterium-depleted water

Containing the natural proportion (or less) of deuterium oxide, i.e. about 0.02 percent

Deuterium-depleted water

Containing the natural proportion (or less) of deuterium oxide, i.e. about 0.02 percent

Liquid-metal cooled fast reactor

Primary heat transport: often Na, Pb, Na-K or Pb-Bi eutectic