There are several different types of reactors as indicated in the following table.


Nuclear power plants in commercial operation
Reactor type Main Countries Number GWe Fuel Coolant Moderator

Pressurised Water Reactor (PWR)

US, France, Japan, Russia

252

235

enriched UO2

water

water

Boiling Water Reactor (BWR)

US, Japan, Sweden

93

83

enriched UO2

water

water

Gas-cooled Reactor (Magnox & AGR)

UK

34

13

natural U (metal),
 enriched UO2

CO2

graphite

Pressurised Heavy Water Reactor “CANDU” (PHWR)

Canada

33

18

natural UO2

heavy water

heavy water

Light Water Graphite Reactor (RBMK)

Russia

14

14

enriched UO2

water

graphite

Fast Neutron Reactor (FBR)

Japan, France, Russia

4

1.3

PuO2 and UO2

liquid sodium

none

other

Russia, Japan

5

0.2

     
 

TOTAL

435

364

     

GWe = capacity in thousands of megawatts.
Source:  Nuclear Engineering International handbook 2000 updated, including Pickering A in Canada.