The Generation III+ VVER-1200 plant, construction of which began in 2009, reached the 100% milestone at 19:23 local time on 31 July.
Rosenergoatom said about 100 key tests need to be carried out with the total testing period expected to last about two months.
This will be followed by testing for 15 continuous days before approval for commercial operation. Full commissioning is scheduled by the end of 2019, Rosenergoatom said.
Novovoronezh 2-2 will be the third unit of its type to be completed in Russia.
The others were its sister unit, Novovoronezh 2-1, which began commercial operation in February 2017, and Leningrad 2-1, which began commercial operation in October 2018.