Mochovce 3 in the next stage of commissioning

16. 1. 2023


Source: Slovenské elektrárne, a. s.

After all prescribed physical start-up tests have been performed, Slovenské elektrárne continues with the next phase of commissioning of the Mochovce Unit 3 - the power start-up..

Earlier in January, Slovenské elektrárne successfully completed the first stage of commissioning of the new nuclear unit, so-called physical start-up. It included dozens of prescribed tests - pressure tests of the containment, primary circuit and steam generators had to be carried out, functionality of the reactor control and protection systems had to be verified, and complex tests had to be carried out to verify all the reactor core characteristics - first without the controlled fission reaction, later at the minimum power of 10-7 to 2% of the nominal power.

A report on the physical start-up results was submitted by Slovenské elektrárne to the Nuclear Regulatory Authority of the Slovak Republic, which issued the approval for the next stage of commissioning of the nuclear installation - the energy start-up on 13 January 2023.

Power commissioning

In this commissioning stage, the reactor power is increased to 5% in the first step and further tests are carried out with simulation of situations that the plant is unlikely ever to experience in normal operation. The power level will be increased step-by step until 100% of the nominal power is reached. At each power level, a series of scheduled tests, approved by the Nuclear Safety Authority of the Slovak Republic, will be carried out.

Once the reactor power is increased to 20 %, when the steam generators are producing sufficient steam, the first turbine-generator and later the second one will be connected to the Slovak electricity system and first megawatt-hours of low-carbon electricity will start flowing into the grid.

The full functionality of Unit 3 and the achievement of the design parameters will be confirmed by successful completion of the 144-hour proof run at full power.

New unit in the Slovak power generation context

The new nuclear unit in Mochovce will have the installed capacity of 471 megawatts at start-up, which will cover approximately 13% of Slovakia's total electricity consumption. In terms of electricity production, Slovakia will thus become energy self-sufficient already this year.

The lifetime of the new unit is planned to be 60 years at least.

Seven out of ten Slovaks support nuclear energy. Up to 60% think it is safe to generate electricity in a nuclear power plant. This is shown by the results of an ACRC public opinion poll conducted for the Slovak Society for Foreign Policy (SFPA) and Slovenské elektrárne in June-July 2022.

About Slovenské elektrárne

More than 64.3% of all electricity generated in Slovakia comes from Slovenské elektrárne. Thanks to nuclear power plants in particular, Slovakia's largest producer supplies up to 94% of its electricity without emitting carbon dioxide, which is considered to be one of the greenhouse gases responsible for global warming. The company is the only one in Slovakia and Eastern Europe to be included in the prestigious Financial Times' Europe's Climate Leader 2022 index for reducing emissions.

In addition to nuclear power plants, the company operates 31 hydro, two thermal and two photovoltaic power plants. Their total capacity is 4143.8 megawatts.

Who are the shareholders

The company has two shareholders. The majority shareholder is Slovak Power Holding B.V. (SPH) with 66.0000000523 % stake in the share capital. In SPH, EP Slovakia B.V. (a subsidiary of the EPH Group) holds 50 % of the share capital and the remaining 50 % belongs to Enel Produzione S.p.A (a subsidiary of the Enel Group).

The minority shareholder of Slovenske elektrárne, with a 33,9999999477 % share in the share capital, is the Slovak Republic, on behalf of which acts the Ministry of Economy of the Slovak Republic.


The complete article including photos you can find here.