The BN-800 fast neutron reactor at unit 4 of the Beloyarsk NPP in Russia’s Sverdlovsk district was connected to the national grid on 10 December. The thermal capacity of the reactor was raised to 25% of its nominal capacity and its K-800-130/3000 turbine reached a speed of 3000 rpm. The generator was then synchronized with the electricity grid and the thermal capacity of the reactor was increased to 35% of nominal capacity. The new unit joined the energy system at a minimum power level of 235MWe.

However, Beloyarsk nuclear plant director Ivan Sidorov said the startup phase is still ongoing, with the next stage being an increase in capacity to 50%, pilot operation and a gradual increase in capacity to 100%. "So we still have a lot of work ahead of us. But the most important milestone in the history of the new power unit has been achieved right now."

Beloyarsk 4 is fuelled by a mix of uranium and plutonium oxides arranged to produce new fuel material as it burns. The reactor was first brought to minimum controlled power in June 2014, with the start of operation planned for the end of that year. But last December Rosenergoatom said nuclear fuel for the unit would first be developed further. The company then said the unit was expected to start operations before the end of this year. It was brought to the minimum controlled power level previously this year in August and November.

Russian nuclear utility Rosenergoatom general director Andrey Petrov said the startup of the BN-800 was an "outstanding event", noting that the previous fast reactor of this type, the smaller BN-600 at unit 3 of the Beloyarsk plant, was launched 35 years ago.

"The BN-800 was constructed in a fundamentally different environment, so its launch, I believe, quite rightly deserves to be recognised as a feat of labour by its designers, engineers, builders, fitters, manufacturers and, of course, its operations personnel," Petrov said. He added that the BN-800 has presented challenges, but "thanks to this unit we have restored our competence in the design and construction of fast reactors". The launch of BN-800 "marks another important step in the transition of Russia’s nuclear industry to a new technology platform", he noted.

Boris Vasilyev, chief BN designer at OKBM said: "The start of the BN-800 confirms the efficiency of the design of the reactor facility, showing the possibility of applying the same basic technical solutions to future projects, primarily in the BN-1200 project now being developed. "