Let us recall that NVNPP power unit No. 6 is the world’s first “3+” generation power unit with PWR-1200 reactors, where they use, as part of the Pilot-industrial operation of NVNPP power unit No. 6 with an extended overhaul period of more than 12 months, an 18-month, more an efficient fuel cycle, in which fresh nuclear fuel is reloaded not once a year, as in a 12-month cycle, but once every 1.5 years. This significantly reduces the duration of repairs, provides an increase in power generation, and also increases the efficiency of the power unit as a whole. This improvement of power units makes them appealing for construction not only in Russia but also abroad. 

“The design of the innovative power unit No. 6 provides for the possibility of implementing more efficient fuel cycles. Almost immediately after the commissioning of new power units, Rosatom State Corporation began to justify the safety of their operation in the 18-month fuel cycle for PWR-1200. Thus, we started work in this area at the Novovoronezh NPP back in 2017,” said Evgeny Golubev, head of the NVNPP Nuclear Safety and Reliability Department.

“In the new fuel cycle, power unit No. 6 has already completed the fourth fuel cycle since August 2020. The equipment of the power unit and the nuclear fuel manufactured by TVEL Fuel Company have proved to be good during this time. Rostekhnadzor confirmed the reliable and safe operation of the power unit and approved the change in the terms of the license for the operation of the nuclear installation of the power unit to continue pilot operation,” he added.

In general, the process of a complete transfer to an 18-month fuel cycle involves a phased transition (pilot operation) from the old type of fuel to the new PWR-1200 fuel in a special version for extended cycles (it differs in the level of uranium enrichment, as well as profiling by burnable absorber - gadolinium), when, over several fuel campaigns, experts gradually remove the old fuel and load the new one. At each of these stages, interaction with Rostekhnadzor is performed. 

At the moment, after receiving permission from Rostekhnadzor, in fact, the start of the last, fifth fuel cycle in the 18-month fuel cycle has been launched, after which another report will be submitted to the Federal Service for Environmental, Technological and Nuclear Supervision. In case of its successful completion and after receiving the next permit from RTN (already for commercial operation), a decision will be made on the final transfer of power unit No. 6 to an 18-month fuel cycle.