Mochovce Nuclear Power Plant

Mochovce Nuclear Power Plant
Mochovce Nuclear Power Plant from the main road between Nitra and Levice
Country	Slovakia
Coordinates	48°15′50″N 18°27′25″E
Status	Operational
Construction began	October 1, 1983
Commission date	October 29, 1998
Owner(s)	Slovenské elektrárne a.s.
Operator(s)	Electrostation Mochovce
Power generation
Units operational	2 x 470 MW
Units under const.	2 x 440 MW
Nameplate capacity	905 MW
Annual net output	6,922 GWh
External links
Commons	Related media on Commons

The Mochovce Nuclear Power Plant (Slovak: Atómové elektrárne Mochovce, abbr. EMO) is a nuclear power plant located between the towns of Nitra and Levice, on the site of the former village of Mochovce, Slovakia. Two up-rated 470 MW (originally 440MW) reactors are presently in operation, with two further reactors of the same type under construction. Generating almost 7,000 GW·h of electricity a year, the power plant currently serves approximately 20% of Slovakia's energy needs.

History

A power plant consisting of four VVER 440/V-213 pressurized water reactors was proposed in the 1970s. The Czechoslovak government began with a geological survey to find a suitable seismically stable site. After taking into account all factors the location of the village of Mochovce was chosen. Preparatory work was started on June 1981, and site construction for Mochovce-1 and Mochovce-2 started in November 1982. The reactors in Mochovce use enriched uranium as their fuel.

Construction of the remaining two units, Mochovce-3 and Mochovce-4, began in 1985 but work on all four units was halted in 1991 due to a lack of funds. In 1995 the Slovak government approved a plan to finish the first pair with additional Western safety technology. The first two units were commissioned in 1998 and 1999 respectively. Commissioning of the plant has sparked protests in Austria, a neighboring country strongly opposed to the use of nuclear energy in general. Installed capacity of units 1 and 2 was up-rated by 7% in 2008. Construction of Units 3 and 4 restarted in November 2008. They were planned initially to be completed in 2012 and 2013, but the completion date was shifted to 2016 and 2017. The owner of the plant is Slovenské elektrárne, a state-owned company, but Enel, an Italian utility company, has the majority ownership in it.

Today

Since late 2008 the two operating units at Mochovce NPP have uprated power output to 235 MWe per turbogenerator, ergo the total installed capacity of units 1 and 2 in Mochovce NPP stands at 940 MWe. In 2009, the plant managed to generate over 7 TWh of electricity during a one-year period for the first time in its history. This represents approximately one quarter of the overall annual electricity consumption in Slovakia. All units at Bohunice and Mochovce NPP feature evolutionary WWER pressurised water reactors, which are characteristic with:

• relatively low power and power density
• huge volume of water for cooling during normal operation as well as in emergency
• robust design with reinforced concrete containment with walls thick up to 1.5 m
• triple redundancy safety system (3 x 100%)
• high level of passive safety.

The principle of electricity generation in nuclear power plants is similar to that of conventional thermal power plants. The only difference is the heat source. In thermal plants, heat is produced from fossile fuels (coal, gas), generating wast quantities of greenhouse gas, whereas in nuclear power plants nuclear fuel is used (natural or enriched uranium). In the pressurized water reactors, fuel in the form of fuel assemblies is placed in reactor pressure vessel to which chemically terated water flows. The water flows through channels in the fuel assemblies and removes the heat that is produced during fission reaction. Water coming from the reactor has a temperature of about 297 °C (VVER reactor type); it is then led through the hot arm of the primary piping into heat exchanger - steam generator. In steam generator, water flows through a bunch of pipes and delivers the heat to water from secondary circuit and has a temperature of 222 °C. When cooled down, primary circuit water is led back to reactor core. Secondary circuit water is evaporated in steam generator and the steam is led via steam collector to the blades of a turbine. The turbine shaft turns a generator that generates electric energy. Having delivered its energy to the turbine, steam condensates in condenser, and getting back to water state, it flows back, via heaters, to steam generator. In condenser, the mixture is cooled by a third cooling circuit. In this latter circuit, water is cooled by air flowing from the bottom to the upper part of the cooling tower due to so-called chimney effect. The stream of air takes along water steam and small water droplets, and that is why clouds of steam form above the cooling towers.

Mochovce 3&4 construction

Units 3&4 of Mochovce NPP are currently under construction. This project is:

• 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.

Construction completion of units 3 and 4 of the Mochovce Nuclear Power Plant must be a priority for everyone. The Prime Minister Robert Fico said so on Wednesday, 8 October, at a government meeting in Žilina in reaction to the agenda of the General Meeting of Shareholders of Slovenské elektrárne, a.s. where the shareholders shall vote on the budget for the Mochovce NPP units 3 and 4. The project director of the Mochovce units construction Giancarlo Aquilanti reported on Tuesday, 7 October, that currently 80% of unit three and 60% of unit four are completed. "Priority of everyone is to complete units three and four at Mochovce. We will therefore wait for the proposal and we will decide accordingly," the Prime Minister of the SR said. The construction site is also important with respect to the employment in the region. There were 5,200 people from 150 contractor companies working at the construction site in the peak times. In total, the number of direct, indirect and induced jobs is estimated to be 9,400. The Slovak companies covered 54% in the construction, the Czech companies took the share of 21% and the Italian ones 10%.

Safety

Although the original power plant design featured safety improvements such as seismically resistant attachment of equipment, it did not suit the safety and regulatory environment of the 1990s. To rectify this the German company Siemens supplied a new control system, and Western and EU safety measures were implemented during the final phases of construction. According to the plant operator Mochovce nuclear power plant was the first Soviet-sourced nuclear plant in the former Eastern Bloc to meet the safety standards of Western nuclear power plants. The nuclear industry was conceived and developed with a conscientious awareness of having to face and respect strict safety guidelines, as well as technical, environmental and health standards. For this reason, safety at a power plant is verified and controlled at maximum possible levels in all of its phases (project design, authorization, construction, operation, decommissioning and final dismantlement), using procedures that have been elaborated exclusively for the needs of this specific sector. In addition, the realization of a nuclear power station is subordinated by a particularly complex authorization process comprising two different components: authorization from a nuclear safety standpoint, and in terms of its environmental impact (EIA – Environmental Impact Assessment). In concrete terms, safety in the electronuclear industry is entrusted to a set of technical, organizational and human measures enacted throughout all stages of an installation's lifetime, with the aim of protecting citizens and the surrounding environment from a release of radioactive material under any circumstances.

Environment

Nuclear power plants emit no greenhouse gas to the atmosphere, in this way NPPs annually contribute to CO2 emission reduction by 15 million tonnes in Slovakia. Nuclear power plants hence contribute significantly to the obligation to reduce emissions of harmful greenhouse gas to the atmosphere. Mochovce NPP meets all international requirements and that the operation impact is minimal. Water required for cooling is taken from a water dam built on the nearby Hron river, which ensures sufficient supply of water even in extremely dry climate conditions. The impact of the discharged waters on the quality of the Hron river water, fauna and flora is negligible. Emissions to the atmosphere and effluents to the hydrosphere are regularly measured and assessed in the 15-km area around the plant. There are 25 monitoring stations of the tele-dosimetry system, which continuously monitor the dose rate of gamma radiation, activity of aerosols and radioactive iodine in the air, soil, water and food chain (feed, milk, agricultural products). The volume of radioactive substances contained in liquid and gaseous discharges is considerably lower than the limits set out by authorities.

Radiation protection

For radiation protection of the power plant staff and population, the ALARA principle is applied. This principle ensures that the radiation exposure inside and outside the power plant is As Low As Reasonably Achievable and well below the limits set by legislation. The impact of the NPP operation on the environment and human health is negligible with respect to other radiation sources present in everyday life. There are 24 monitoring stations of the tele-dosimetry system in the 20 km radius around the power plant, which continuously monitors the dose rate of gamma radiation, volume activity of aerosols and radioactive iodine in the air, soil, water and food chain (feed, milk, agricultural produces). The volume of radioactive substances contained in liquid and gaseous discharges is considerably lower than the limits set out by authorities.

Stress tests

Immediately after the Fukushima accident, European politicians, representatives of the nuclear industry and regulatory bodies agreed on the undertaking of power-plant safety reviews. All 15 member states of the EU operating nuclear power plants were involved. The testing of the two Bohunice NPP V2 units and all four Mochovce NPP units was carried out mainly through engineering analyses, calculations and reports. Stress tests analysed extraordinary external events – earthquakes, floods, and impacts of other events that might result in the multiple loss of power-plant safety functions. The combination of events, including loss of power supply, long-term water supply breakdown, as well as loss of power supply due to extreme climate conditions were also assessed. Stress tests revealed no deficiencies requiring immediate action; the further safe operation of neither the operating units nor the units under construction was put in doubt. Identified measures would further increase nuclear safety, for example by adding mobile diesel-generator for recharging of back-up batteries.

MO34 Construction: Benefits for region of Mochovce

Nuclear power plants are the pillar of the Slovak power industry, supplying over 50% of electricity to the grid and contributing to international commitment of Slovakia in reducing the greenhouse gas emissions. Mochovce 3&4 completion is the largest single private investment in the history of Slovakia. Some 3,500 people work on site. Nearly 60% of the work on site is performed by Slovak companies. In order to improve and make communication with the public more transparent, regional associations of municipalities were established at Mochovce and Bohunice regions, who nominate members to Civic Information Committees. Those are in direct contact with the power plants management. Visitor centres are also available for the broad public at both locations. The Company supports local projects in the areas of culture, education, nature, sport and the social area through the Energy for the Country programme.

Technical data

Station	Reactor type	Net capacity	Commissioned	Grid date	Exp. shutdown
Mochovce 1	VVER 440/213	436 MWe	4 July 1998	29 October 1998	2058
Mochovce 2	VVER 440/213	436 MWe	20 December 1999	11 April 2000	2060
Mochovce 3	VVER 440/213	440 MWe	under construction	(09/2016)	-
Mochovce 4	VVER 440/213	440 MWe	under construction	(06/2017)	-

See also

• Energoland

External links

• Official presentation of Mochovce NPP