The Russian 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 for efficient nuclear fission. VVER reactors are known for their robust safety features and are widely used in various countries for electricity generation. VVER reactors come in different models, with the most common being the VVER-440 and VVER-1000. These reactors have been continuously improved over the years, incorporating advanced technology to enhance safety and efficiency. They play a significant role in the nuclear energy sector, contributing to energy security in many regions.