VVER
The water-water energetic reactor (WWER), or VVER (from Russian: водо-водяной энергетический реактор (ВВЭР), romanized: vodo-vodyanoi enyergeticheskiy reaktor) is a series of pressurized water reactor designs developed in the Soviet Union and Russia by OKB Gidropress. The name refers to the use of water as both the nuclear coolant and the neutron moderator, in a reactor intended for energy generation.