Fast-neutron reactor
（重定向自Fast reactor）
![Shevchenko BN350 nuclear fast reactor and desalination plant situated on the shore of the Caspian Sea. The plant generated 135 MWe and provided steam for an associated desalination plant. View of the interior of the reactor hall.](/Images/godic/202501/12/Shevchenko_BN3504240.gif")
![Shevchenko BN350 desalination unit. View of the only nuclear-heated desalination unit in the world](/Images/godic/202501/12/Shevchenko_BN350_desalinati4241.jpg")
A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons. Such a reactor needs no neutron moderator, but must use fuel that is relatively rich in fissile material when compared to that required for a thermal reactor.