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The BN-800 unit at the Beloyarsk plant is sodium-cooled, which means it does not use the same control systems as pressurised water reactors. "This introduces some operational peculiarities and adds a number of advantages, such as increased safety and reliability due to the physical and technical properties of sodium," Rosatom said.
Testing of the Vizuz system took place over a week on a rig five storeys high, with the control software and the precision of the system assessed by a team which included representatives from six Russian nuclear organisations.
It was judged to be effective, with reactor testing now set to be the next step - "the ultrasonic transducer will be inserted into the reactor core by a manipulator, aimed at specified coordinates, or automatically scan the space above the core, and then removed from the scanning zone".
Ilya Filin, Chief Engineer of the Beloyarsk Nuclear Power Plant, who led the team, said: "During the scheduled maintenance in 2026, a sound-monitoring system is planned to be installed in the reactor. Once the system is confirmed to be operational on the BN-800, a package of documents will be submitted to Rostekhnadzor (Russia's nuclear regulator) to amend the licence conditions, and operating instructions and repair documentation will be developed."
The technology is being considered for future BN-1200M units.
The background
The sodium-cooled BN-series fast reactors are part of Rosatom's project to develop fast reactors with a closed fuel cycle whose mixed-oxide (MOX) fuel will be reprocessed and recycled.
In addition to the BN-600 reactor at Beloyarsk unit 3, which began operation in 1980, the 789 MWe BN-800 fast at Beloyarsk unit 4 entered commercial operation in October 2016.
This is essentially a demonstration unit for fuel and design features for the larger BN-1200M, which will be unit 5 at Beloyarsk. It entered the preparation stage for construction in July and has a target completion date of 2034.
