An inspection of the reactor vessel has been started at the VVER-1200 unit No. 5 of the Leningrad NPP. A team of the NDT inspectors of the power plant and experts from manufacturing companies will study its condition using the tools of an automated control system. The works are conducted within the framework of the ongoing preventive maintenance of the power unit.

According to Chief Engineer at Leningrad NPP-2 Aleksandr Belyaev, this is the first large-scale and serious test of the reactor after two years of operation that followed the commissioning of the unit in October 2018. The work is done on condition of complete extraction of nuclear fuel from the vessel. All research is carried out remotely using high sensitivity sensors and manipulators that can work underwater. These measures ensure safe working conditions of the NDT operators.

“Experts will assess the interior condition of metal the reactor vessel is made of for the first time, as well as control whether its integrity and structure changed due to prolonged exposure to radiation, high temperatures and a significant pressure. They will be using ultrasonic and television control equipment to achieve that. In case the reactor vessel is corrosion free and shows no signs of cracking or hidden internal defects, the reactor will be admitted as operation ready until the next maintenance period, during which a complete fuel extraction will be performed,” - Aleksandr Belyaev explained.

A reactor vessel is not just a vessel that contains a controlled chain reaction which releases a high amount of heat. It is also a physical barrier that prevents contamination of the environment due to spread of radioactive materials and ionizing radiation. For that reason, operational control is highly significant for the safe operation of an NPP.