The Leningrad NPP has for the first time used an automated system to run maintenance tests and repair the cladding of walls and the bottom of the spent nuclear fuel pool.

The robot worked in live conditions under a layer of water directly in the spent fuel pool of NPU No. 6. This pool is the intended storage location for spent nuclear fuel.

The storage pool is a reinforced concrete structure with a metal cladding filled with boric acid water. The integrity and leak-tightness of the pool is an important component of the nuclear and radiation safety of a nuclear power plant. Much attention is paid to monitoring its condition.

“There is no robot in the world similar to this one. The personnel are responsible for the maintenance and repair of the pools. They perform the extraction of fuel assemblies and drain the boric acid,” says Chief Engineer of the LNPP Aleksandr Belyayev. “It takes several days. And our robot manages this task within several hours, with no need of removing the spent nuclear fuel.”

The robot is a multipurpose system equipped with a high-precision positioning system and video surveillance, which allow it to perfectly navigate the pool without removing water and fuel.

The system can use the ultrasound to detect every possible leak, locate its coordinates, clean up the defective surface and repair the metal lining by welding. The operator monitors and controls the entire technological process using a special panel.

In case of emergency, the robot will allow to promptly fix any leaks in the spent fuel pool and maintain the necessary water level, which allows to avoid the baring and subsequent melting of the loaded fuel assemblies. This also minimizes the number of required operations with the spent fuel.

The interest in this device is very great today, and not only among Russian nuclear power plants, but all over the world. Robots for diagnostics and welding at depth are 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.