Romania to restart second unit of nuclear power plant after months offline

Romania’s Ministry of Energy announced that the start-up sequence for Unit 2 of the Cernavodă Nuclear Power Plant was initiated on Monday, November 9.

The reactor is expected to resume operation on Tuesday, November 10, after the Danube's water flow allowed the gradual resumption of nuclear power production, according to Economedia.

The restart of the second reactor comes after Unit 1 of the same nuclear plant was reconnected to the National Energy System (SEN) on Friday, November 6, following almost three months of shutdown.

The two reactors at Cernavodă have an installed capacity of approximately 700 MW each and account for around 20% of Romania's electricity production under normal operating conditions.

Romania was without nuclear power production for about 100 days after both units were shut down in succession amid very low Danube water flow, which reduced the water available to cool the reactors. Unit 1 was shut down in a controlled manner on July 28, while Unit 2 was shut down in mid-August.

The first reactor was reconnected to the grid on November 6, and its output gradually increased. On Saturday, November 7, prime minister Luca Niculescu announced that Unit 1 was operating at about 50% capacity and was expected to reach 100% within the next 24 hours.

The prime minister then stressed the importance of the reactor's return for Romania's energy security, particularly during the winter. During the shutdown period, Romania had to rely on expensive energy imports to cover its needs.

Warning for future

The simultaneous shutdown of the two reactors over the summer and much of the autumn brought renewed attention to the plant's vulnerability during periods when the Danube's water flow is very low.

Niculescu announced that the Bala 2 project, which aims to redistribute water flows to the Old Danube branch on which the Cernavoda plant is located, must be treated as a priority by state institutions. The larger volume would allow the Cernavodă plant to cool the existing reactors and the future Units 3 and 4.