Slovak power producer Slovenské Elektrárne (SE) has completed a successful cold hydraulic test of unit 3 of the Mochovce NPP – a key step in the commissioning process. It “confirmed the functioning of all tested components and took us closer to commissioning the plant,” said SE director Branislav Strýček said on 23 August. The tests began in mid-July and lasted for 38 days. The main objective was to demonstrate that the plant systems and components such as the pressure vessels, pipelines and valves of both the nuclear and conventional island are leak proof, and to clean the main circulation pipes. The primary circuit during the test was pressurised to 13.7 MPa (more than 111% of the operating pressure) and heated up to 120°C. The steam generators were tested from the secondary circuit side, as well as feedwater and live steam pipelines at the pressure of up to 7.65 MPa (more than 166% of operating pressure).
The power plant will now be prepared for hot testing. “The power plant will be prepared as if for nuclear operation,” said Peter Andraško, general manager of the project. “But instead of nuclear fuel we will use imitations.” The unit is expected to begin operation during the second quarter of 2019 and unit 4 should follow within one year.
Work on Mochovce 3 and 4 started in 1986 but was suspended for 16 years and resumed in late 2008, and it was scheduled to end in 2012 and 2013 at a cost of €2.8 billion. However, the completion date and cost has been revised several times. The most recent budget for completion is €5.4 billion, and it could increase further according to Strýček. The two new units in will have a capacity of 471MWe, which will account for about 13% of the total electricity consumption in Slovakia. However, SE said the capacity may later be uprated to 535MWe.
The units have an evolutionary design based on the VVER-440 V-213 pressurised water reactor with safety upgrades that make the units compliant with current national and international nuclear safety standards. The nuclear island suppliers include Inžinierske Stavby Košice for civil works; Škoda JS, Enseco and VUJE for the mechanical systems; PPA for the electrical systems and equipment; and Areva/Siemens for the control system. Other suppliers include ASE, Rolls-Royce and GSE. The conventional island suppliers are ZIPP for the civil works; Škoda Power and Modrany Power for the mechanical systems; and ČKD, PPA, Energo & Schneider, Brush SEM and Techimp for the electrical systems and equipment.
SE is owned by the Slovak government, with a 34% stake, and a joint venture between Italian utility Enel and privately-held Czech energy group EPH. Enel acquired its stake in SE in 2006 for €840 million and undertook to complete Mochovce 3 and 4 as part of the transaction. However, in 2014, it launched a programme to sell its holdings in Romania and Slovakia, in an effort to reduce its financial debt. Enel sold half of its 66% stake in SE to Czech energy group EPH in mid 2017, and plans to sell its remaining 33% after completion of the two new units.
