Mochovce-3 Connected To The Grid For The First Time

On 1st February, the Slovak operator Slovenské elektrárne announced that Mochovce-3 has been connected to the grid for the first time on Tuesday, 31st January, at 10:57 pm local time.

The plant reached this important milestone less than three weeks after the Nuclear Regulatory Authority of the Slovak Republic gave its approval for the beginning of the power start-up on 13 January 2023.

After the transition to power start-up, tests were conducted successively at the levels of 5, 15 and 20% of the reactor’s rated power, with measurements and tests of both nuclear and non-nuclear parts of the plant.

The secondary circuit was heated up and steam lines blown down, cold and hot flushes of turbine condensers and low-pressure regenerators as well as feedwater lines were done, and tests of steam generator relief valves were carried out.

Once this part of the power start-up was completed, Slovenské elektrárne could proceed to the actual synchronisation of the first turbine-generator with the grid at 20% of the reactor’s nominal power and the Mochovce 3 began to supply the first electricity to the grid.

The unit has now to be tested at various power levels ranging from 35% to 100%.

Mochovce-3 has a VVER-440 pressurised water reactor (PWR), with an installed capacity of 471 MW.

The unit achieved its first criticality on 22 October 2022 after fuel loading a month earlier.

Once operational, Slovenské elektráne said also that the generation from Mochovce-3 will cover about 13% of Slovakia’s total electricity consumption, increasing the share of nuclear energy in the total electricity mix from 52% to 65%, putting the country second behind only France.

Furthermore, the annual production of the reactor will save 2.6 million tonnes of CO2 emissions annually.