The 2024 annual report of Russia's Federal Nuclear and Radiological Security Program contains data on spent fuel reprocessing at the RT-1 plant at Mayak.
The "irradiated standard uranium blocks" are fuel elements that were used in plutonium production reactors. BOR, SM, and MIR are research reactors.
The nominal capacity of the RT-1 plant is 400 tonnes of fuel a year. Historically, it has been reprocessing about 110-130 tonnes of fuel a year.
The document also shows that the cumulative total amount of reprocessed fuel in 2016-2024 was 993 tonnes.