Light water reactor

A light-water reactor is a nuclear reactor in which ordinary H ₂ O water is used to slow down neutrons and / or as a coolant. The term is used to distinguish from a heavy-water reactor , in which heavy water D ₂ O is used as a neutron moderator. Both atoms in heavy water hydrogen replaced by heavy hydrogen atoms - deuterium .

Normal water, in contrast to heavy water, not only slows down, but also significantly absorbs neutrons (by the reaction ¹ H + n = ²D). Therefore, if water is used in a light-water reactor both as a coolant and as a neutron moderator (as, for example, in VVER , PWR , VK-50 reactors ), then the reactor cannot operate on natural uranium, for the operation of such a reactor, preliminary enrichment of uranium is required. If graphite serves as a neutron moderator, and ordinary water is used only as a coolant, then the reactor can, in principle, operate on natural uranium or low enriched uranium (such as the RBMK reactor ). A heavy water reactor can also operate on natural uranium, this is one of its main advantages.

It should be noted that the division of reactors into light-water and heavy-water is a common practice. Heavy water power reactors were not built in the USSR and Russia , therefore, in fact, all types of Russian water reactors ( VVER , GWR ) are light-water.

Classification:

• Water - neutron moderator, water - coolant:
  • Water-cooled nuclear reactors ( WWER , PWR )
  • Boiling water-water reactors ( VK-50 , BWR)
• Graphite - neutron moderator, water - coolant:
  • AM-1, AMB, EGP-6 , RBMK , MKER
• Graphite - neutron moderator, gas - coolant:
  • Magnox Reactors