The VVER (Water-Water Energetic Reactor) is a type of pressurized water reactor (PWR) developed in the Soviet Union. It uses water as both a coolant and a neutron moderator, allowing it to efficiently generate electricity through nuclear fission. VVER reactors are known for their robust safety features and have been widely used in various countries. VVER reactors come in different models, with the most common being the VVER-440 and VVER-1000, named for their electrical output capacity. These reactors are designed to meet international safety standards and have undergone numerous upgrades to enhance their performance and reliability in power generation.