On Saturday, 9 July 2022 at 10:56 a.m. Slovenské elektrarne completed the second scheduled general overhaul of this year at Bohunice V2 Nuclear Power Plant by connecting the first turbine to the power grid, during which 73 fuel cartridges in the reactor and 18 392 tubes in the main condensers of both turbines were replaced.
The unit is shut down once a year after just over 300 days of effective operation. The start date is set by calculations by nuclear physicists who determine how many and which fuel assemblies are to be replaced. In addition to fuel replacement, projects such as overhaul of the steam generator, main coolant pump and feed water pumps were carried out during this outage. They also performed heterogeneous weld modifications on the feedwater, diesel generator oil cooler, cooling tower pool cleaning and inspection, and main condenser tubes replacement.
Prior to the actual start-up of the reactor the prescribed pressure tests of the primary circuit and steam generators were performed. Following successful physical start-up tests and the phasing of both turbines, the power output of the reactor and turbines was increased to nominal power.
"Our goal is safe and reliable operation throughout the next campaign."
Patrik Kašo, Director of Bohunice V2 Nuclear Power Plant
Slovenske elektrarne are facing one more general overhaul this year at Mochovce on reactor Unit 2.
The planned general overhaul (GO) of Bohunice NPP Unit 3 starts with the shutdown of turbine generators on Saturday morning, 18 June 2022. One fifth of the fuel in the reactor will be replaced during the outage. Workers from Slovenské elektrárne, a.s. and contractors will carry out planned repairs to one of the plant's three redundant emergency safety systems.
Priority activities on the plant's primary (nuclear) circuit equipment include overhaul of one of the six steam generators and one main circulation pump, repair of the control rod nozzles, and repair of a heterogeneous weld on the steam generator feedwater.
On the secondary, non-nuclear circuit, the main activities include the overhaul of the tertiary circuit pump, cleaning and inspection of one cooling tower pool. At the same time, Slovenske elektrarne will implement 23 capital construction projects to further improve safety - those that cannot be done during normal operation. These include, for example, the replacement of approximately 19,000 tubes in the main condenser of both turbine-generators.
"We are starting the general overhaul of Bohunice Unit 3 just one and half a week after the completion of the GO of Unit 4, which requires extraordinary commitment and effort of the staff to manage it perfectly, without unnecessary complications in terms of occupational health and safety, fire, radiation and nuclear safety."
Mr. Patrik Kašo, Director of Bohunice Nuclear Power Plant
As the last of the four nuclear units operated in Slovakia, the second unit of the Mochovce NPP will undergo this year’s general overhaul in September 2022. Each of the four VVER 440 pressurised water reactors, which are the only reactor type in operation in Slovakia, must be shut down at least once a year for a planned partial refuelling. All reactors in operation in Slovakia are owned by Slovenské elektrárne, a.s.
On Wednesday, 8 June, Slovenské elektrárne completed the first of two consecutive planned general overhauls at the nuclear power plant.
The outage of the fourth Bohunice unit lasted over three weeks and involved a number of standard works and investment projects, including a test of the so-called start-up from blackout. For the first time ever, Slovak power engineers successfully tested their readiness for a possible total blackout in the west of the country at a nuclear power plant.
Read more: We successfully simulated blackout in Jaslovské Bohunice - SEAS
At the same time, an overhaul of one of the steam generators, two main circulation pumps, a low-pressure part of one turbine, as well as the replacement of the tubes of the main condensers of the turbines was performed at the Bohunice power plant.
The main objective of the overhaul was, as with any planned overhaul, to replace one fifth of the fuel in the reactor. Prior to restarting the nuclear unit, the plant checked leak tightness of the primary circuit in a pressure test.
We have implemented one hundred percent of all planned capital projects and operational checks, which will ensure safe and reliable operation of the unit throughout the coming year.
– Patrik Kašo, Director of Bohunice NPP
Slovenské elektrárne schedule to shut down the Bohunice nuclear power plant Unit 3 in June. Unit 2 of Mochovce will be the last unit to undergo a general overhaul this year.
The planned general overhaul of the fourth unit of Bohunice Nuclear Power Plant starts on Saturday, 14 May with the shutdown of the turbine generators. As every year, one fifth of the fuel in the reactor will be replaced during the overhaul. Slovenske elektrarne and contractors will inspect the reactor pressure vessel and carry out planned repairs to one of the plant's three redundant emergency safety systems.
Priority activities on the primary (nuclear) circuit components of the power plant include also scheduled works on three of the six steam generators, as well as overhauls of the two reactor coolant pumps.
On the secondary, non-nuclear circuit, the main activity is the overhaul of the stator and rotor of the high and low pressure parts of one turbogenerator. In parallel, Slovenske elektrarne will perform 26 investment projects to further enhance safety - works that cannot be done during normal operation. These include, for example, restoration of design reliability of sprinkler coolers of safety systems, or replacement of some 19 000 tubes in the main condenser on the turbine generator (TG41).
"We realise how important it is to carry out both overhauls at the Bohunice plant safely, efficiently and smoothly in this turbulent period. We are prepared in terms of personnel and material for all planned activities related to the overhauls," said Patrik Kašo, Director of the Bohunice power plant.
One month after this overhaul, the third unit of Bohunice NPP is scheduled to be shut down. Unit 2 of Mochovce will be the last to undergo a general shutdown in 2022. The overhaul of the first one was in April and lasted for three weeks.
Each of the four VVER 440 pressurised water reactors, which are the only type of reactor in operation in Slovakia, must be shut down at least once a year for a planned partial refuelling. All reactors in operation in Slovakia are owned by Slovenske elektrarne, a.s.
The planned GO of the Mochovce Unit 1 lasted three weeks and included a number of standard works as well as implementation of investment projects such as measures enhancing seismic resistance of components and buildings or unit transformer replacement.
The main goal of the overhaul was the replacement of a fifth of the fuel in the reactor and performance of planned repairs and inspection of important components of the power plant, which can only be performed when the Unit is shut down. Before restarting the reactor unit, tightness of the primary circuit was verified by a pressure test.
„I am very pleased that we carried out all the planned activities during the general overhaul to the expected quality and according to schedule. We have completed the design changes to increase the seismic resistance of the technological systems located in the containment, thus increasing the level of nuclear safety of this unit.“
- Miroslav Tokár
Director of Nuclear Power Plant Operation Division
This year, Slovenské elektrárne is planning the overhaul of the fourth unit of the in Bohunice V2 nuclear power plant in May, followed a month later by unit three, and the last overhault in 2022 will be the general overhaul of the second unit of Mochovce NPP.
Slovenské elektrárne express sorrow over the loss of life in Ukraine. We condemn Russia's attack on the civilian population of Ukraine, on civilian targets, including nuclear facilities. We express our support and solidarity with our colleagues and partners in the nuclear power plants in Ukraine, who are doing their utmost to carry out their tasks - to produce electricity safely. They are doing a difficult job, and their personal safety must be ensured.
We join the call by the International Atomic Energy Agency and the World Nuclear Association to stop all violence at all nuclear facilities. It is necessary for plant workers and rescue teams to be able to carry out their duties. Shooting on the premises of a nuclear power plant violates the fundamental principle that the physical integrity of nuclear facilities must be maintained and kept safe at all times. We also join the urgent call from the world's nuclear experts for the creation of safe zones around all nuclear power plants in Ukraine to ensure the safety of all nuclear facilities and their personnel.
In recent days, Slovenské elektrárne have tightened and strengthened the security of their power plant facilities, including cyber security.
Slovenské elektrárne are monitoring the situation very closely, communicating and cooperating with partners at the IAEA, WANO, WNA, ÚJD and other national and international stakeholders.
The majority shareholder of Slovenské elektrárne, Slovak Power Holding, signed a Memorandum with the Ministry of Economy of the Slovak Republic and the Ministry of Finance of the Slovak Republic on the implementation of extraordinary measures to eliminate the impact of the increase in electricity prices on selected groups of consumers.
In the memorandum, Slovak Power Holding undertakes to take such steps so that Slovenské elektrárne could reserve electricity for 2023 and 2024, which would be sold to selected groups of customers at fixed prices. According to the Memorandum, 6.15 terawatt hours should be set aside for selected groups of customers at a price of EUR 61.20. The total value of the support will amount to approximately EUR 850 million.
At the same time, the Government hereby withdraws the bill from the so-called excessive profit in trading with electricity generated by nuclear facilities, the adoption of which would threaten the bankruptcy of Slovak Power Plants. The Ministry of Finance and the Ministry of Economy have committed not to take any initiative between 2022 and 2025 to introduce, increase or tighten any new tax, levy, fee, specific payment or regulation that could financially jeopardise Slovenské elektrárne.
"The shareholders of Slovenské elektrárne have offered a mechanism of assistance to vulnerable groups of the population for the years 2023 - 2024, so that the viability of the company, its ability to meet its obligations to banks and creditors, and at the same time so that we can continue work on the commissioning of Unit 3 of the Mochovce nuclear power plant and the completion of Unit 4 are not threatened. It is these new sources that will provide energy for Slovakia for a long period into the future at a time when Europe is facing and will face a shortage of stable electricity supplies," says Branislav Strýček, CEO of Slovenské elektrárne.
"The agreement managed to avert the imminent economic collapse of the Slovenské elektrárne. We believe that we will be able to defend this support model before the financing banks and find their understanding," says Jan Špringl, a shareholder representative and member of the Board of Directors of Energetický a průmyslový holding.
"We appreciate that the Slovak government reflected the arguments of the shareholders and the management of the company and I am glad that we were able to find a substantive solution for both sides," added Michele Bologna, representative of the shareholder - Enel Group.
More than 64.3 % of all electricity generated in Slovakia comes from the Slovenské elektrárne. The electricity they supply to the grid covers about 60 % of the country's consumption. In particular, thanks to nuclear power plants, Slovakia's largest producer supplies up to 94 % of electricity without emitting carbon dioxide, which is considered to be one of the greenhouse gases responsible for global warming. In addition to nuclear power plants, the company also operates 31 hydroelectric, two thermal and two photovoltaic power plants. Their total capacity at the end of 2021 was 4,143.8 megawatts.
The company has two shareholders. The majority shareholder is Slovak Power Holding B.V. (SPH), holding a 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 elektrární with a 33,9999999477 % share in the share capital is the Slovak Republic, on behalf of which the Ministry of Economy of the Slovak Republic acts.
The essential activities of the outage, which should last less than four weeks, include works on technical water system, emergency reactor core cooling systems, electrical switchgear stations and non-destructive inspections of the reactor pressure vessel.
Repairs of control rod welds and replacement of control rod absorbers are scheduled, as well as inspections and repairs of heterogeneous welded joints of steam generators. The plant will also undergo repairs at one of six reactor coolant pumps and other works. The schedule also includes a containment tightness test.
In parallel, works on investment projects will be underway. The most important of these are the unit’s efficiency increase by 7 per cent, installation of an electric boiler and a long-term seismic resistance enhancement project, which will include some measures to increase the seismic resistance of switchboards and transformers, as well as severe accident management projects.
Once the overhaul works are over, Mochovce 2 will operate at half power – with only one turbine generator, until another turbine is replaced in November.
In Slovakia, the September overhaul of Mochovce 2 is the last planned nuclear overhaul this year. However, at the same time it is this year’s first overhaul with unchanged, full scale scope of works, with presence of foreign contractors. They must comply to strict conditions set by the Chief Hygienist of the Slovak Republic and management of Slovenske elektrarne within the prevention measures in place against the spread of the new coronavirus.
Slovenské elektrárne performed all required inspections of systems and components during the extended revision with the aim of assessing their conditions following the hot hydraulic testing and before the fuel loading into the reactor.
The extended revision included a thorough inspection of the reactor as well as other primary circuit components, particularly reactor internal structures, reactor coolant pumps, pipelines, pressurizer, etc. dismantling, inspection works, and re-assembling of the reactor and other primary circuit components, i.e. reactor internal structures.
Slovenske Elektrarne performed visual, tightness, pressure, ultrasonic and other tests to check integrity and quality of the primary circuit components and for detection of impurities or foreign objects.
The company continuously rectifies some of the findings resulting from testing of systems performed so far, prepares additional more detailed analyses, and will repeat some tests done during the hot hydraulic testing.
The extended revision will be completed by reactor readiness for fuel loading following the repeated Mochovce NPP Unit 3 heating, assessment of additional required tests and repeated primary circuit pressure test, as conditions for authorisation to load fuel into the reactor.
Slovenske Elektrarne does not expect any significant impact of the activities on the schedule and budget, technical readiness for fuel loading shall be achieved in autumn 2019.
Mochovce NPP Unit 3 primary circuit extended revision is the last stage before the initial fuel loading into the reactor.
Slovenské elektrárne strongly objects to the way in which the anti-nuclear organisation Global2000 is scaremongering through reports about the Mochovce nuclear power plant. Referring to an anonymous source, the anti-nuclear group claims that the massive, meter and half thick reinforced concrete containment wall of the new reactor at Mochovce plant is not safe enough due to the drilling for anchoring technological equipment at the nuclear site.
The claim is misleading, false, and shows the absolute ignorance on the side of Global2000 with regard to complex projects to increase the seismic resilience of both existing and under-construction sites, and is intended to spread fear and panic among the inhabitants of Austria and Slovakia as well.
During the construction of Mochovce units 3 and 4, Slovenské elektrárne implemented a comprehensive seismic reinforcement project, with more than 60 000 steel anchoring plates installed that were fully in compliance with the engineering calculations and the approved project design. The outcome was an increase in the resistance of both units to potential earthquakes at the Mochovce site, whereby the company attained a situation exceeding international standards applied in this field.
Over the recent weeks, Slovenské elektrárne has thoroughly tested the tightness of the containment of the nuclear power plant, with excellent results. The containment parameters showed that under the pressure of 150 kPa the achieved results were twice as good as the limits set by the Slovak Nuclear Regulatory Authority (NRA). We therefore strictly reject any statements of insufficient tightness or weakness of the containment.
The aim of the Austrian anti-nuclear organisation Global2000 is to stop the commissioning of units 3 and 4 of the Mochovce installation by any means, including the increased media pressure on the Austrian government. To this end they use the means bordering on false scaremongering rumours. We consider their requests and proposals to be deliberately false and we refuse them in their entirety.
Below we attach the full wording of Slovenské elektrárne’s response to the request for a meeting addressed to us by Global2000 in February this year:
Dear Ms. Lorenz,
respectfully, we decline your request. Your organization’s key mission is to stop all nuclear activities by any and all means all around the world. Our goal is to continue production from nuclear. Nuclear has been one of the safest ways of producing electricity in the world and the single largest source of low carbon electricity in Europe, saving million tons of CO2 emissions. Many top scientists, environmentalists and climate experts, including James Hansen, James Lovelock, Ken Caldeira, Carlo Rubbia, Ted Nordhaus and many other notable authorities throughout the world agree that nuclear must be a part of the fight against climate change. Our operating power plants have had excellent track records in all aspects of their operation. We continue to communicate the progress on the Mochovce site with our key stakeholders, public officials and many others. As in the past, we will continue to provide answers to all relevant questions within the process managed by the Nuclear Regulatory Authority. But we find our views irreconcilable and consider your effort as nothing but a pretext to further spread nuclear phobia.
Allow me to use this opportunity to quote from the Open Letter to Environmentalist on Nuclear Energy: “Although renewable energy sources like wind and solar will likely make increasing contributions to future energy production, these technology options face real-world problems of scalability, cost, material and land use, meaning that it is too risky to rely on them as the only alternatives to fossil fuels. Nuclear power—being by far the most compact and energy-dense of sources—could also make a major, and perhaps leading, contribution. As scientists, we declare that an evidence-based approach to future energy production is an essential component of securing biodiversity’s future and cannot be ignored. It is time that conservationists make their voices heard in this policy arena.”
Others experts have taken similar approach. Bill Gates, for example, supported nuclear by saying just last December “Solar and wind are intermittent sources of energy, and we are unlikely to have super-cheap batteries anytime soon that would allow us to store sufficient energy for when the sun isn’t shining or the wind isn’t blowing. Nuclear is ideal for dealing with climate change, because it is the only carbon-free, scalable energy source that’s available 24 hours a day.”
It is an irrefutable fact that nuclear shut-dows, which is your ultimate goal in all countries, have and will lead to replacement by or delayed phase-out by fossil fuels everywhere, with Germany being a notable example of a country unable to meet its climate goals and even lower its emissions from electricity generation because of that. This is confirmed by no other than the Union of Concern Scientists, one of the worlds’ foremost watchdogs, which for this very reason even called for “temporary financial support to avoid the early closure of nuclear plants” and stated that “limiting the worst effects of climate change may also require other low- or no-carbon energy solutions, including nuclear power”.
I will be more than happy to meet you when I see that you can accept views differing from your own and recognize nuclear as one of the legitimate ways to produce low-carbon electricity. Allow me conclude my answer with a statement of Dr. Fatih Birol, Executive Director of the International Energy Agency, who said at the Central European Energy Conference in Bratislava last year the following: “We all have our favorite fuels, some wind, some solar, some nuclear. But we have to decide, what is our aim. Is our aim to increase our ego or reduce CO2 emissions? We have to make a choice."
