Leningrad NPP said on 14 May that for the first time it had used a robotic system that has no analogues anywhere in the world to diagnose and repair the lining of the walls and the bottom of the used nuclear fuel pool. The robot worked in real conditions in the cooling pool at unit 6 of the plant, where the used fuel elements will be stored after being unloaded from the reactor. The storage pool is a reinforced concrete structure with a metal lining, filled with water containing boric acid. The integrity and tightness of the pool is an important component of the nuclear and radiation safety of a nuclear plant.
“There is nothing similar to this robot anywhere in the world. Diagnostics and repair of pools at NPPs are normally carried out by personnel. To do this, it is necessary to unload the fuel cells and drain the boric solution,” noted the chief engineer of the Leningrad-II NPP, Alexander Belyaev. “It takes several days, and our robot can complete the task in a few hours. In addition, there is no need to remove fuel from the pool."
The robot is a multifunctional complex equipped with a high-precision positioning system and video surveillance, which allows it to navigate the pool without emptying it of water and fuel. Robots for diagnostics and welding at depth can be used not only in the nuclear industry, but also in shipbuilding, in the repair of port infrastructure, in the laying of oil and gas pipelines, etc.
Leningrad 6 (also known as Leningrad-II 2) only began commercial operation in March and has yet to undergo refuelling. As a result it was possible to test the robot in an empty storage pool.