Units 3 and 4 at Mochovce NPP, Slovakia
The Completion of Mochovce NPP is currently our biggest project
Completion of Units 3 and 4 at the Mochovce Nuclear Power Plant is currently our biggest engineering investment project. We produced and delivered two VVER 440 reactor pressure vessels. At this time, we act as the supplier of not only the power plant’s essential operating systems, i.e., the primary circuit and fuel handling part, but also connecting pipes, intermediate cooling circuits, parts of the instrumentation and control system, and maintenance workshops. This contract is very beneficial for us in terms of the maintenance and development of invaluable experience in managing large investment projects.
We are one of the five main suppliers. The contract for the delivery of the key primary circuit and fuel handling systems was concluded with Slovenské elektrárne, a.s. in 2009. In the following years, addenda to the contract were signed, which officially confirmed an extension of the entire contract and an increase in the volume of assembly works as well as the scope of services provided by ŠKODA JS.
The design, delivery, assembly and cold start-up stages at Unit 3 have already been completed. Successful completion of the cold and hot hydro hydrostatic test programs confirmed the high quality of our assembly works. The hot hydrostatic test program took place at the beginning of 2019 at temperatures and pressures close to those during regular operation and it was successfully completed in 03/2019. Immediately thereafter, the stage program of the so-called complex inspection was launched, which is formally still ongoing, since it actually ends with the loading of nuclear fuel, which depends not only on the SE (an instruction to seal-off the reactor and complete the remaining activities of ŠKODA JS within the large inspection) but also on a formal permission by the Slovak Nuclear Regulatory Authority (UJD) – i.e. issue of the First Instance Decision, which is expected until the end of 2020. Within its scope of work, ŠKODA JS is fully prepared for the fuel loading. The investor is expected to load fuel into Unit 3 in the first quarter of 2021, which will start the phase of physical and power start-up. After a successful 144-hour trial run, the works on Unit 3 will be concluded and the Unit will be handed over to the customer through the preliminary acceptance milestone.
In 2020, activities leading up to the completion of assembly works and the launch of construction tests continued at Unit 4. The flushes of the piping systems, long-postponed by the investor, are to be performed, which will be followed by removal of the temporary flushing fittings, design-state installations and completion of the construction tests. Subsequently, a sequence of cold tests and stage programs will be started, identical as those at Unit 3.
Throughout the construction process, ŠKODA JS provides the investor with specialists in key areas, such as engineering, planning, licensing support, construction and assembly works and start-up. The start-up of Unit 3 is currently scheduled to take place in the second quarter of 2021, while the start-up of Unit 4 is planned in half of 2023.
The history of our cooperation
The timeline of our cooperation on Units 3 and 4 at Mochovce NPP
2009 ŠKODA JS and Slovenské elektrárne signed a contract for the completion of Units 3 and 4 at Mochovce NPP
2011 we developed and supplied a special cask of our own design, KSV 440, for witness samples of pressure vessel steel at Units 3 and 4
2013 we developed and supplied equipment of our own design for the removal, transport and disposal of neutron flux sensors and thermocouples from the VVER 440 reactor
2013 ŠKODA JS and Slovenské elektrárne signed an addendum to their contract to extend the project and increase the volume of work and services provided by our company
2017 we completed the control assemblies of reactor internals at Unit 4
2018 cold hydrostatic testing was performed and the program of hot hydrostatic testing commenced at Unit 3
Assembly works are under way at Unit 4 to be followed by construction tests
2019-2020 hot hydrostatic test program and complex inspection were performed at Unit 3