Mochovce 3&4 construction

Mochovce 3&4 Project Completion (01/01/2016)
  • one of the three projects of nuclear power plants currently under construction in Europe
  • the largest private investment in the history of Slovakia
  • 2/3 of works on site is performed by Slovak companies
  • 90% of the population around power plant is in favour of the completion of Units 3&4
  • each unit will have 471 MWe output
  • annual production of two units will save over 7 million tonnes of CO2 emissions
Mochovce 3&4 project progress: Cummulative man-hours

Construction progress at Mochovce NPP units 3&4

1st quarter 2015

  • Insulation of tanks for the emergency feedwater system.
  • Erection of horizontal and vertical cable trays in the turbine hall of unit 3 +9.6 m.
  • Erection of ventilation in the ancillary building continued.
  • Pipelines and pumps for boron concentrate were added.
  • Erection of stainless steel lining of the spent fuel pool.
  • Demineralized water system was installed for turbogenerator TG41.
  • Erection of the steam separator in the turbine hall of unit 4 continued.
  • Pipelines and valves for residual heat removal were erected in the turbine hall of unit 3.
  • Welding of stainless steel lining of the spent fuel pool.

2nd quarter 2015

  • Erection of 688 anchoring plates in unit 3 and 1 588 plates in unit 4.
  • 386 out of 396 rooms in the reactor building were prepared for the erection of technology in unit 3.
  • Hydrotests concerning the fire water lines on the conventional island of unit 3 were completed. Installation of smoke detectors in the I&C rooms was completed as well.
  • In the conventional part of unit 4, construction test of emergency demineralized water tank was carried out. 

3rd quarter 2015

  • Construction test and hydrotest of the tank (emergency feedwater system for steam generators).
  • Construction works were carried out following the erection of fire flaps and freon pipelines in two rooms.
  • In the ancillary building, 140 rooms out of 155 were prepared for the erection of technology.
  • Functional tests of the cooling water system were carried out.
  • The construction of anti-aircraft barriers continued.
  • Concrete works in the common diesel generator station continued.
  • We delivered a new TG32 turbogenerator for unit 3.
  • Hydrostatic tests of the sealing of the spent fuel pool lining were carried out.

4th quarter 2015

  • In unit 3, conditions for clean assembly in the reactor hall were reached and control reactor assembly started together with renovation of internal reactor parts.
  • The control room of unit 3 was energized, and the nuclear project entered the testing and commissioning phase. Individual tests of the I&C system have commenced.
  • Preparations for installation of the pipelines of generator TG42.
  • Functional tests of process control systems in the cross-side electrical building continued.
  • Installation of common diesel generator.
  • Under the supervision of the Nuclear Regulatory Authority of the Slovak Republic, Slovenské elektrárne verified the special professional skills of its shift engineers, unit heads and unit operators. The verification has to be done one year before the commencement of physical commissioning of the reactor unit.
  • Completion of Full Scope Simulator site acceptance testing.
  • Commencement of functional tests of medium voltage switchboards at Mochovce Power Plant Unit 3.
  • Unit 3 Control Rooms (main control room, emergency control room, common control room) assembled for start of Commissioning activities.
  • Start of Mochovce 3&4 operators training at the Full Scope Simulator; following the completion of licensing process for operators training by the Nuclear Regulatory Authority of the Slovak Republic.
  • Submission of "Pre-Operational Safety Analysis Report" to the Nuclear Regulatory Authority of the Slovak Republic. The document is the key for authorization of Fuel Loading to Unit 3.
  • Unit 3 Main Control System: 90 % of internal cabling of Unit 3 Main Control System (total: 9.000 cables) completed.
  • Unit 3 Nuclear Island: Civil Readiness of over 90 % of NI rooms needed for Unit 3 Commissioning. Instrumentation room (1 out of 3) with impulse lines, penetrations impulse lines and racks completed. The room is ready for the installation of the instruments. Radioactive waste treatment piping installed.
  • Reactor hall civil works completed which is the first step towards Strict Clean Conditions required for Reactor internals works.
  • Unit 3 Conventional Island: First phase of 6kV busbars commissioning completed. Mechanical completion of the main systems (non-essential and essential service water, main steam, feed-water, condensate, high and low pressure air systems). Up to 100 km of main cable trays erected (100 %).
  • As of the end of 2014, the Unit 3 was 81% and the Unit 4 was 63% completed.
  • Civil readiness of Unit 3 Nuclear island critical rooms.
  • Completed the Detailed Design of Unit 3 Anchoring Plates.
  • Start of mechanical erection activities in the Nuclear island critical rooms.
  • TG31 and TG32 Final assembly, bearing closing, turning gear installation, insulation assembly.
  • Completion of Mechanical Erection of Unit 3 Main Steam and Feedwater systems.
  • Individial tests of Unit 3 LV/MV Cabinets.
  • Unit 3 – Distributed control system power up.
  • Full Scope Simulator
    • Application Software Installed and Tested;
    • Site Acceptance Tests.
  • Refurbishment of hermetic cable penetrations at the Units 3&4.
  • Fire protection lining and painting in auxiliary nuclear building
  • Civil readiness for foundations under pipe bridge
  • Concrete floor drainage in room A217
  • Transport and assembly of 7th section of spent fuel pool in Unit 4
  • Installation of instrumentation and control system cabinets
  • Welding of stainless-steel lining floors on Unit 4 in A201/2, A301/2
  • Grouting activities - works under the tripods of primary circuit of Unit 4
  • Assembly of penetrations on the shaft no. 1 of Unit 4
  • Concreting of floors and vertical elements in the vent stack
  • Modernization of main circulation pump 3, 6
  • Refurbishment of main circulation piping
  • Erection of diagnostic system on steam generator 6
  • Welding of support ring under core basket
  • Erection of removable part of main circulation pump 2-6
  • Three stand supports straining of main circulation pumps 1-6
  • Transport of frames and pumps of sprinkler and low pressure emergency injection system
  • Erection of bellows
  • Blowing through the steam generator 1
  • Commissioning of 110 kV back-up electric source
  • Concreting of Unit 3 reactor postament
  • Installation of 400kV electric switch yard
  • Fresh nuclear fuel storage prepared for technology installation
  • Assembly of all four steam turbines of Units 3 & 4 completed
  • Safe Enterprise certificate for SE-MO34 site
  • Refurbishment of internal walls of vent stack;
  • Refurbishment of roof of nuclear auxiliary building;
  • Refurbishment works of condensate tanks on the roof of auxiliary nuclear building;
  • Seismic reinforcement of reactor building;
  • Seismic reinforcement of internal walls of auxiliary nuclear building;
  • Refurbishment of internal walls of connecting bridge;
  • Installation of earthing networks of vent stack;
  • Civil readiness of the emergency room in a simulator building;
  • Hydrotest of spent fuel pool of Unit3 (shaft No. 1);
  • Grouting of mechanical equipments (primary coolant pumps);
  • Civil readiness for refurbishment of reactor upper block;
  • Refurbishment of hermetic and non-hermetic zone in reactor building (Unit 3,4);
  • Foundations for pipe bridge; 
  • Refurbishment of external walls of auxiliary nuclear building;
  • Internal seismic reinforcement of connection bridge;
  • Erection of fire protection lining in auxiliary nuclear building;
  • Concreting works on postament of unit 3;
  • Heavy concreting on postament of Unit 4;
  • Reinforcement on postament of Unit 4 around shaft no.1;
  • Concreting works around reactor pit of Unit 3;
  • Erection and welding of main circulation piping in the steam generator box;
  • Reactor pressure vessel of unit 4 transport and placement (2-3/12/2011);
  • First turbine of Unit 3 installation (December 2011).
  • Seismic reinforcement of reactor building roof;
  • Seismic reinforcement of external structures of reactor building;
  • Seismic reinforcement of steel structures of the turbine hall;
  • Erection of new bridge crane in turbine hall;
  • Refurbishment of turbines supports;
  • Seismic reinforcement of internal steel structures of auxiliary nuclear building;
  • Refurbishment of steam generators (unit 3);
  • Refurbishment of 250t crane in the reactor hall;
  • Reinforcement of roads, corridors and slabs for the reactor pressure vessel transport;
  • Refurbishment of auxiliary structures for transport of reactor pressure vessel;
  • Refurbishment of external walls of vent stack;
  • Refurbishment of cooling towers;
  • Reactor pressure vessel of unit 3 transport and placement (3-4/9/2010);
  • Refurbishment of anchoring structures of steam generators (unit 3);
  • Refurbishment of bubble condenser (unit 3);
  • Refurbishment of external walls of reactor building;
  • Removal of old moisture separators and reheaters (unit 3);
  • Refurbishment of hermetic penetrations;
  • Refurbished rooms in reactor building, number of rooms ready for mechanical erection:
    • Unit 3: 328 out of 353;
    • Unit 4: 197 out of 239.
  • Main nuclear island contracts, EPCM contract for the conventional island and main I&C Engineering contract were signed and activities have started;
  • Contractors' mobilization works completed (site services, site offices, ...);
  • Evaluation of existing components;
  • Refurbishment of reactor hall roof;
  • Seismic reinforcement of the external walls of the reactor building.
20000BC: Inhabited by humans, stone axe found 20 000 BC
Inhabited by humans, stone axe found
1 259 AD
First written mention of a settlement called Mohi
1 259 AD: First written mention of a settlement called Mohi
1 981: Start of construction works at Mochovce – ground works 1 981
Start of construction works
at Mochovce NPP – ground works
Start of construction works on Mochovce NPP unit 1 and 2
Start of construction works on Mochovce NPP unit 3 and 4
Replacement of the instrumentation and control system
Halt of the construction works
Re-start of conrtruction works on unit 1 and 2
Commissioning of Mochovce NPP unit 1 and 2 1998
Commissioning of unit 1

Commissioning of unit 2
Enel acquired 66 % of Slovenské elektrárne
Unit 1 and 2 installed output increased to 107%
Start of the Mochovce NPP 3&4 completion project


Main suppliers

Civil works: Inžinierske stavby Košice

Mechanical systems: Škoda JS, ENSECO, VUJE

Electrical systems and equipment: PPA

Control system: Areva / Siemens

Other suppliers: ASE, Rolls-Royce, GSE

Civil works: ZIPP

Mechanical systems: Škoda Power, Modrany Power

Elektrical systems and equipment: ČKD, PPA, Energo & Schneider, Brush SEM, Techimp