Nuclearelectrica schedules Unit 1 resynchronisation for 6 November

Unit 1 due back on 6 November

Nuclearelectrica scheduled resynchronisation to the National Energy System for Friday 6 November. It said Unit 1 would reach full capacity on 7 November. The procedures began after the minimum conditions for a fully safe synchronisation were met, the company said.

The restart comes earlier than the government's late-October guidance. Romania said then it expected both reactors to stay offline throughout November. It has extended a state of energy emergency through November, allowing it to cut power to industrial consumers in stages.

Why one reactor matters

The two 706 MW reactors at Cernavoda together account for about a fifth of Romania's power output, Nuclearelectrica said. Unit 1 alone restores about half that share, roughly a tenth of national generation.

With both units down, Romania lost more than 1,400 MW of installed nuclear capacity. It relied on renewable power and costly imports to offset the shortfall, and it reopened some lignite-fired capacity. Cross-border capacity of about 4,000 MW left room to buy abroad, several times the size of Unit 1.

The river that stopped the plant

Nuclearelectrica shut Unit 1 on 28 July and Unit 2 in August. The Danube fell to record lows. The river cools the plant. At its entry into Romania, flow had dropped to 1,650 cubic metres per second. That compares with a July average of about 4,750.

For 12 to 19 August the national hydrology institute expected 1,350 to 1,400 cubic metres per second. That compares with an August average of about 3,900. Romania tried engineering first. It sank four rock-filled barges and blasted a rock to push water toward the intake. It still had to take the second reactor offline.

The energy ministry said it had turned on a 330 MW lignite plant. Oilprice, citing a state secretary at the ministry, identified the restarted unit as Rovinari Group 4 and put its addition at nearly 300 MW.

What happens next

Nuclearelectrica gave no date for Unit 2. It said reconnecting the reactor depends on a sustained rise in Danube levels. Operating Unit 1 requires large volumes of water to cool the reactor, which will lead to a drop in the water level in the intake basin, the company said.

Longer term, Nuclearelectrica plans two more 700 MW reactors at Cernavoda using the same technology. It targets them for 2031 and 2032, roughly the capacity of the existing pair. The government still has to carry out works on the Danube branch where the plant sits. The aim is to prevent a repeat.