Nuclear: security structure
Kyiv and Moscow traded blame on Sunday after a fire broke out at a cooling tower of the Zaporizhzhia nuclear power plant, under the control of Russian forces.
Zaporizhzhia's pressurized water reactors are similar to French nuclear reactors, whose security structure is presented in this videographic. VIDEOGRAPHIC
Zaporizhzhia's pressurized water reactors are similar to French nuclear reactors, whose security structure is presented in this videographic. VIDEOGRAPHIC
Transcript
00:00French nuclear power plants are protected by three separate barriers.
00:12In a reactor vessel, the core is made up of uranium pellets stacked in rods surrounded
00:17by metal cladding.
00:18The first barrier, the cladding, the fission produces heat.
00:22The reactor core is cooled by a closed water circuit at 300 degrees Celsius.
00:28This is the primary circuit.
00:30The second barrier.
00:32This water, pressurized to keep it in a liquid state, is channeled towards the steam generator.
00:38When it comes into contact with the very hot pipes through which the primary circuit flows,
00:43the water in the secondary circuit heats up and is transformed into steam.
00:48The steam powers a turbine, which then turns an alternator to produce an electric current.
00:54As it exits the power plant, this current is transported through a network of extra
00:59high voltage lines.
01:00On leaving the turbine, the steam is transformed back into water to be returned to the steam
01:06generator for a new cycle.
01:08By passing through a condenser, the steam becomes liquid again.
01:12This condenser is fed either by cold water taken from the sea or a river, or with water
01:17cooled by air currents that circulate in large towers called air coolers.
01:22Finally, the third barrier is the containment structure.
01:26It consists of one concrete wall for 900 MW plants and two for 1,300 and 1,450 MW plants.
01:35This enclosure, better known as the reactor containment, holds the main components of
01:40the primary circuit.
01:52For more information, visit www.fema.gov