Cold testing verifies that welds, joints, pipes and components in the primary circuit are able to withstand pressures higher than those during normal operation.
The ministry said the core of the Russia-made VVER-1200 pressurised water reactor unit was loaded with dummy fuel assemblies at the time of testing.
In April 2021, the first fuel batch for Belarusian-2 was delivered onsite following the loading of dummy fuel assemblies in March 2021.
According to the latest government schedule, Belarusian-2 is expected to begin commercial operation in 2022. However, physical startup for the unit is expected in the autumn of 2021, according to reports.
There are two 1,109-MW VVER-1200 reactor units at the Belarusian site near the town of Ostrovets, in western Belarus, close to the border with Lithuania. Construction of Unit 1 began in November 2013 and of Unit 2 in April 2014.
Belarusian-1 has been connected to the grid and was recently granted a commercial licence by authorities.