Screenshot 2016-05-12 22.57.18


Pavol SirokyScreenshot 2016-05-09 19.10.39


Unit 3 and Unit 4

Presentation at the NEC Conference in Prague on  April 5, 2016


The justification for the construction of MO 3+4 echoes the one given for

MO 1+2

  • The Meciar government had argued the need for the construction of Mochovce unit 1+2 as a replacement for the decommissioned NPP V1 in Jaslovske Bohunice. These reactors have been in service at Mochovce since 1998.
  • The Fico government again used the need for replacing NPP V1 in Bohunice as justification for the completion of Mochovce unit 3+4.


History of Mochovce 3+4

 1987: construction begins

1992: cessation of building activities followed in 1993 by the commencement of mothballing activities


  • July 15 – ambiguous statement of the European Commission regarding the project to complete NPP Mochovce unit 3+4
  • August 14 – decision of the Slovak Nuclear Regulatory Authority to approve the modifications of the restart project. Extension of the building license for Mochovce 3+4 until December 31, 2013 (in 2008 70% of the buildings and 30% of the installations had been completed).
  • November 3 – „festive“ inaugural celebrations to mark the completion of Mochovce 3+4


  • Work starts on the further extension of Mochovce NPP 3+4
  • February 16 – plans for the environmental impact assessment (EIA) addressing the operation of Mochovce 3+4 are presented to the Slovak Ministry of Environment (Start of the EIA process – objections to the project brought forward by the public).
  • June – signing of the contracts with the suppliers of the nuclear installations at the power plant (companies involved: ŠKODA JS, Atomenergostroj, VÚJE, ENSECO, Inžinierske stavby Košice)


  • planned start of operations at MO 3 – currently planned start of operations at MO 3 only by 2017!


  • planned start of operations at MO 4 – currently planned start of operations at MO 4 only by 2018!


Societal problems of the Mochovce 3+4 project

  • EIA – process was only initiated after NGOs had exerted pressure for more than a year – lawsuit because of the lacking EIA-procedure.
  • Minimal information of the public
  • Misleading information to the public: Mochovce 3+4 supposedly equipped with a containment! „The system of containment at Mochovce 3 + 4 is in full compliance and in accordance with requirements put forth by IAEA and WENRA“
  • In August 2008 the construction license has been extended (2012, 2013) – while EIA-procedures had not yet been concluded – this happened only by February 2009.



Cost-explosion overruns the project of Mochovce 3+4

  • In September 2008 costs amounted to 1,8 bn. €, in 2015 the sum had increased to 4,6 bn. €!
  • Insufficient levies for the National Nuclear Fund, scuttling the proposition that the cost of electricity from Mochovce NPP will be low (the levies would have to be at least 3 times higher) – even so, at least 100 €/ Mwh will be required.
  • Insufficient liability of the operator of the NPP in the case of nuclear damages
  • Mochovce NPP does not solve the problem of dependency concerning the import of fuel raw materials.


Many security problems at Mochovce 3+4

  • The projected completion of Mochovce 3+4 NPPs will not be able to offer the level of safety of new reactors. Fundamental design parameters do not allow a complete adaptation to current standards of best practice in technology and science. The possibilities for improvements are limited. It is hard to believe that 40 year old technology can be interpreted as state of the art. No new equipment can change the underlying technology and safety standards inherent in the project.
  • The problem of waste disposal concerning spent fuel remains unsolved.
  • Lack of a containment
  • This project is incapable of withstanding the impact of a big commercial airliner.
  • Unproven resilience of the barbotage condenser system at the maximum pressure surge envisaged
  • Risk of loss of integrity of the reactor vessel or of the steam generator piping


Problems relating to the operation of Mochovce 3+4 NPP

  • Need for major backup capacities – Slovak reactors tend to be off-line for 2-3 months per year (repairs, incidents, refueling)
  • Fine-tuning of output is not possible (100% or 0%)
  • Efficiency is too low – 30%
  • Centralized source of energy – high rate of loss due to grid
  • Should a single reactor become unavailable, a substitution for 10% of the electricity demand in the whole country has to be found
  • Preponderance of one source of energy – presently more than 54%, the share of nuclear is slated to rise up to 75% after Mochovce has been upgraded = unbalanced system, endangering the energy supply of the country.

Fire protection is focused on the confinement and extinguishing of fires, it is not concerned with the abolition of potential initiating hazards.

  • Reactors of the VVER 440/V213 design do not systematically assure separation of cables and wires of redundant system components. It is impossible to retroactively correct the insufficient separation of redundant systems.


Earthquake resilience

  • When this VVER 440/V213 unit was originally projected, earthquakes were not being taken into account. Safety mechanisms were supposed to withstand the so-called 10.000 year quake.
  • At Paks NPP and Bohunice V2 NPP the subsequent study of earthquake risk led to the conclusion that seismic countermeasure are necessary, as a maximum acceleration of 0.25 g (IAEA 1999) has to be expected.
  • Mochovce 1+2 were originally designed to withstand an earthquake of level 4 and a maximum horizontal acceleration of 0.06 g. After seismological investigations an earthquake of level 7 and a maximum horizontal acceleration of 0.1 g was assumed as design basis for the project.
  • According to SE, AG the seismic upgrade at Mochovce 3+4 has been declared capable of handling up to 0,15 g.


Confinement poses risks

VVER 440/V213 containments have limited pressurizing capabilities.

The VVER 440/V213 design uses confinement, a system of outer boxes encasing important components in the primary loop. Isolation of radioactive steam, which can be expected to be leaking in the event of a major accident, is not contained by the VVER 440/123 reactor design, it has to be transformed utilizing a peculiar system of condensation. In the course of pressure reduction this confinement could burst, thus releasing radioactive particles into the environment. After the execution of various trials and mechanical enforcement of this barbotage condensation system, functionality of the installations in the case of certain design basis incidents could be established. However, efficacy of the system in the case of major accidents has not been sufficiently demonstrated.


Power increase – at Mochovce 1+2 as well as at Mochovce 3+4 power increasing to 107% of the originally envisaged performance is possible.

Among other things power upgrades modify the inventory of radioactive particles and thus radiological effects besides enhancing power output. Safety margins decline and aging of components is accelerated. Therefore, the risk of operating sites that have undergone such performance upgrades increases.


High burn up rates

Increased profitability of the NPP – longer intervals between refueling outages. Requires higher enrichment of the fuel in the assemblies.

High burn up (50 MWd/kg) = intensified embrittlement of the fuel rod tubes + enhanced emission of fission products by the fuel pellets (NEA 2002). These changes can negatively effect options available for emergency cooling in the event of an accident involving the highly radioactive primary loop.


Reduction of testing and inspection times

An increase of the capacity factor by shortening reactor maintenance times translates into increased profits. To accomplish this goal new technologies are put into service. Tests that have traditionally been conducted during maintenance outages are now being executed during operation while the reactor is running at full load.

However, tests are most effective when the reactor is shut down. Whenever tests are performed while the reactor is on-line, it must be assured that operating safety margins are not compromised. In particular, the remediation of defects must not be jeopardized. Performing tests while in full power mode enhances operational risk.

Current regime: testing of reactor vessels is at present scheduled at 4 year intervals at Mochovce 1+2 and at Bohunice V2. At Mochovce 3+4 an extension of this interval to 8 years is envisaged.


License extensions

Design lifespan for VVER 440/V213 originally planned – 30 years. Whoever seeks the establishment of extended operating licenses for Mochovce 3+4 NPP to 40 or even 60 years must accept that modified initial requirements for materials used, for the resilience of installations and for documentation standards must be adhered to.


Power uprating leads to accelerated aging of the installations.


The combination of operating extensions and power uprating may increase the profitability of operating a NPP, but it also tends to reduce safety margins.

Components presently stocked at Mochovce 3+4 are in a better condition than the components already installed (AQUILANTI 2007). Aging of Mochovce 3+4 started even before operations commenced. It can be demonstrated that Mochovce 3+4 is riddled by various safety risks inherent in its design. These risks are supposedly eliminated by modernization measures. However, the success of these measures is not assured and an independent review of these issues is not possible, which is highly problematic.


Complications in regard to public participation 

  • August 2013: the Supreme Court of the Slovak Republic annulled the ruling of the Slovak nuclear regulatory body that enables the construction of Mochovce 3+4 NPP. The Nuclear Regulatory Authority of the Slovak Republic acted unlawfully when it denied NGOs participation in the proceedings.
  • Furthermore the Supreme Court ruled that an EIA has to be conducted. The licensing process was to be repeated.
  • Construction work at Mochovce NPP was to be halted.
  • The Slovak Nuclear Regulatory Authority initialized a new licensing process, but at the same time issued a ruling on August 21, 2013, overturning the deferral order, thereby enabling the continuation of building activities at Mochovce NPP while the new licensing procedures are conducted.


Obstructing access to information

  • The documents released by the Slovak Nuclear Regulatory Authority make it impossible to comment on the safety, quality and conceivable impacts on the environment of the NPP.
  • Most important papers have either not been published or they have been partially blackened. This even holds true for information readily available from sources in the public domain.
  • The agency also designated information regarding the handling of radioactive waste as secret. Of course the production of radioactive wastes is a direct consequence of operating the site. It is impossible to judge the impacts on the environment without knowledge of this essential factor.
  • Current Slovak legislation (Ruling enacted 2010 – nuclear regulation and law governing access to information) enables the Slovak Nuclear Regulatory Authority de facto to declare as secret whatever they wish to hide from the public. This is in disagreement with the Aarhus convention.


The charade around Mochovce is compounding deep concerns about the safety of the NPP, as the official regulatory body blocks the public from gaining access to information on the environmental implications of Mochovce 3+4 in this absurd fashion, thereby preventing citizen stakeholders to participate in the licensing process.


Thank you for your attention.


Report: NEC2016 Conference:

„Nuclear Energy – Expensive Gamble“

There were three opening and eight main speeches presented at the Nuclear Energy Conference 2016 held in Prague on April 5. The conference website includes the presentations, profiles of the speakers, photos and audio recordings of all three sections in three languages.

Speakers expressed their surprise at how there is still a need to talk about the unresolved safety problems 30 years after Chernobyl and five years after Fukushima. It was highlighted that energy economics has changed: today we need flexible electricity systems and small units such as renewable energy sources. These are getting cheaper, with almost zero operating costs and negligible costs of disposal in comparison to nuclear power plants. A pressing need to reduce risks associated with radioactive releases to the environment was mentioned and how the associated risks increase with a plant lifetime extension. In connection with this there were serious concerns raised about an indefinite [1] license to operate the first block of the Dukovany nuclear power plant which was issued in March 2016.

On the accidents at Three Mile Island and Chernobyl (the Jaslovské Bohunice accident in 1977 was also discussed briefly) it was concluded that until now nuclear accident modelling approaches have always failed because they were not able to incorporate the human factor. It was made clear that high standards for nuclear energy exist, but only on paper with no implementation in practice. Safety culture of operators and their control by the state authorities are lacking. Furthermore, operators are trying to save money on safety measures. The audience discussed these topics in relation to the presentations on the EU’s new Nuclear Safety Directive and limited liability. It has been pronounced that civil society participation is indispensable in order to improve safety culture. Also, to prevent disasters such as Chernobyl, the consequences of which have become more obvious nowadays. The TORCH study [2] has shown that at least additional 40,000 deaths in Europe are inevitable due to radioactive fallout after Chernobyl.

As was said in the opening speech, the coming two years should indicate the future direction of the European energy industry. Whether billions will be invested to subsidize new and current nuclear projects, whether a legal action against the Hinkley Point C project in the UK will succeed and whether subsidies for nuclear energy will be banned, based on a legal ‒ not political ‒ decision. We can only hope that by then no nuclear accident caused by aging nuclear power plants will occur. There are serious concerns with aging reactors, as stated in the presentations devoted to technological parameters of the Belgian, Slovakian and French plants. Serious shortcomings of nuclear power plants in Hungary, Romania, Bulgaria and the Czech Republic were also commented upon in the presentation on safety ’stress tests‘.

Olga Kališová, Calla (April 18, 2016)

Nuclear Power in Slovakia

(Updated 12 October 2015)

  • Slovakia has four nuclear reactors generating half of its electricity and two more under construction.
  • Slovakia’s first commercial nuclear power reactor began operating in 1972.
  • Government commitment to the future of nuclear energy is strong.

Electricity consumption in Slovakia has been fairly steady since 1990a. Generating capacity in 2012 was 8.2 GWe, almost one quarter of this nuclearb. In 2013, 28.5 billion kWh gross was produced, 15.7 TWh (55%) of this from nuclear power, with hydro 5.1 TWh, coal 3.3 TWh, gas 2.4 TWh and solar 0.6 TWh. Net imports were zero. Slovakia has gone from being a net exporter of electricity – of some 1 billion kWh/yr – to being a net importer following the shutdown of the Bohunice V1 reactorsc. All of the country’s gas comes from Russia. Per capita electricity consumption in 2012 averaged 4430 kWh.

In November 2014 the government approved a long-term energy plan based on greater use of nuclear power, some renewables, and reducing the use of coal.

Nuclear industry development

In 1958, the Czechoslovak government started building its first nuclear power plant – a gas-cooled heavy water pressure-tube reactor at Bohunice (now in Slovakia). This 110 MWe net Bohunice A1 reactor, built by Skoda, was completed in 1972 and ran until 1977 when it was closed due an accident arising from refuellingd.

In 1972, construction of the Bohunice V1 plant commenced, with two VVER-440 V-230 reactors supplied by Atomenergoexport of Russia and Skoda. The first was grid connected in 1978, the second two years later. In 1976, construction started on two V-213 reactors (the V2 plant) built by Skoda. The V2 units commenced operation in 1984 and 1985. All were designed by Atomenergoproekt.

Despite major upgrade work on the two V1 unitse, the units were shut down at the end of 2006 (unit 1) and 2008 (unit 2) as a condition of Slovakia’s accession to the European Union (see section below on EU accession). In 2013 the EU Parliament Committee on Budgetary Control complained that it was “unacceptable” that these reactors were not in irreversible shutdown.

From 2005 to 2008, operator Slovenské Elektrárne (Slovak Electric, SE) carried out a major modernization program on the two Bohunice V2 units, to improve seismic resistance, cooling systems, and instrumentation and control (I&C) systems with a view to extending operational life to 40 years (2025). This was followed by a progressive uprating program of both units1, eventually bringing the capacity of each unit from 440 gross to 505 MWe gross (472 MWe net) by November 2010. The total cost was reported to be €500 million. SE is planning to extend the licences of the V2 units to 2045 following upgrading.

In 1982, construction on the first two units of the four-unit Mochovce nuclear power plant was commenced by Skoda, using VVER-440 V-213 reactor units. Work on units 3&4 was started in 1986 and halted in 1992. Units 1&2 started up in 1998 and 1999. These two units have been significantly upgraded and the I&C systems replaced with assistance from Western companiesf. Uprates of 7% at Mochovce 1&2 were implemented by June 2008.

Construction of units 3&4 was reactivated in mid-2009 and the units were expected to commence operation in 2012 and 2013 and €2775 million was allocated to the completion project. See section below.

Bohunice V2 and Mochovce are owned and operated by SE. In 2006, Italian utility ENEL acquired a 66% stake in SE. The remaining 34% is held by the state through the National Property Fund. ENEL has sought bids for its stake in SE, and expects to decide among these in 2015. In June 2015 China National Nuclear Corporation (CNNC) said it planned to bid for ENEL’s share of SE. In July ENEL said it would sell SE in two stages: first to reduce the 66% to below 50% in 2015, probably selling to the state, then the rest once Mochovce 3 & 4 are completed. In August 2015 ENEL said it was negotiating the sale of its SE equity with Czech-based company Energeticky a Prumyslovy Holdings (EPH).

The Nuclear Decommissioning Company, Javys, owns Bohunice A1 and V1.

Operating Slovak power reactors

Reactor Model Net MWe First power Expected


Bohunice V2-1      V-213 472 1984 2024
Bohunice V2-2 V-213 472 1985 2025
Mochovce 1 V-213 436 1998
Mochovce 2 V-213 436 1999
Total (4) 1816 MWe


New nuclear capacity

In October 2004, the government approved Italian Enel’s bid to acquire 66% of Slovenské Elektrárne (SE) for €840 million as part of its privatisation process. Enel’s subsequent investment plan approved in 2005 involved €1.88 billion investment to increase generating capacity, including €1.6 billion for completion of Mochovce units 3&4. The estimated cost of this project has more than doubled since then.

In January 2006, the government approved a new energy strategy incorporating these plans, which includes capacity uprates at Mochovce 1&2 and the Bohunice V2 units.

Slovak power reactors under construction, planned and proposed

Reactor Model gross MWe Construction start First power Operator
Mochovce 3 V-213+ 471 6/09 late 2017 SE
Mochovce 4 V-213+ 471 6/09 2018 SE
Bohunice New Block VVER? 1200 2021? 2025? Jessk
Kecerovce ? 1200 After 2025 ?
Total under construction (2) 942 (440 net each)

Plans for new nuclear build were outlined in the October 2008 Energy Security Strategy of the Slovak Republic, which incorporates the nuclear power plans in the 2006 Energy Policy. The 2008 Energy Security Strategy aimed to maintain the proportion of electricity generated by nuclear power plants at around 50% through the following measures:

  • Completion of Mochovce 3&4 by 2013 (880 MWe gross).
  • Uprates at Bohunice V2 and Mochovce 1&2 by 2010 (180 MWe gross).
  • Uprates at Mochovce 3&4 by 2015 (60 MWe gross).
  • Construction of a new reactor block at Bohunice by 2025 (1200 MWe gross).

In addition, around 2025, when the two V2 units will have reached 40 years of operation, the strategy calls for either life extension of the V2 units or for the construction of 1200 MWe of new nuclear capacity at Kecerovce in the east of the countryl.

Further information: