(Updated 2021)


This report provides information on the status and development of nuclear power programmes in Slovenia, including factors related to the effective planning, decision making and implementation of the nuclear power programme that together lead to safe and economical operations of nuclear power plants (NPPs).

This report also summarizes organizational and industrial aspects of nuclear power programmes, provides information about national strategic plans and the relevant legislative, regulatory and international framework in Slovenia.

Slovenia has one nuclear power reactor in operation, Krško NPP, which started commercial operation in 1983 and provided 37.8% of electricity production in 2020. Krško NPP is in the process of plant life extension. Slovenia is also in the process of planning a new NPP, JEK2. Based on the national energy and climate programme, the decision on the new NPP will be made by 2027. The issued energy permit for JEK2 from July 2021 opens the way for the implementation of administrative and preliminary planning procedures for investment decision-making.



Slovenia imports half of its primary energy demand and all of its oil and natural gas. In 2019 the country’s energy supply consisted of around 33% oil, 22% nuclear, 16% coal, 11% natural gas, 11% combustible renewables and waste, 6% hydro and 1% other renewables (solar and wind). Energy dependency as of 2019 stood at 51.5%.

Final energy consumption (FEC) in 2019 amounted to 205.4 PJ, a decrease of 2% compared with 2018. The largest consumer of energy is the transport sector at 40%, followed by manufacturing and construction at 29%, households at 22% and other use (including agriculture) at 10%. FEC by energy source consists of oil at 45%, electricity 24%, renewables and waste 13%, natural gas 12%, heat 4% and other renewables 1%.

  1. Energy policy

The energy policy goals of Slovenia are to ensure a reliable, safe and competitive energy supply in a sustainable manner by ensuring a low carbon transition and achieving United Nations Sustainable Development Goals. Future development of the energy industry is centralized among three general and inextricably linked energy policy pillars , namely climate sustainability, energy supply security and competitiveness.

In 2020, Slovenia prepared its National Energy and Climate Plan (NECP) for the next 20 years, which was adopted by the Government on 27 February 2020. The NECP includes an analysis of different scenarios for the contribution of the European Union to meeting its own and Member States’ commitments under the United Nations Framework Convention on Climate Change and the Paris Agreement. According to the EU Regulation 2018/1999, which entered into force on 24 December 2018, European Union Member States were required to prepare integrated NECPs that cover the five dimensions of the energy union for 2021–2030 with long term planning up to 2040, according to the drafted governance of the energy union and climate action rules.

The objective of reducing greenhouse gas emissions affects the share of renewable energy sources in the final consumption of energy. Currently, Slovenia’s national objective is set at 27% by 2030 and confirmed by the Slovenian Development Strategy 2030. According to the World Energy Council, Slovenia remains a strong World Energy Trilemma performer with high scores in the energy security, energy equity dimension and environmental sustainability (balance grade ABA and global ranking 14 for 2020 rating).

Slovenia will strive to reduce the use of and dependency on fossil energy sources to the greatest extent possible, by gradually phasing out their use, advancing the efficient use of energy and increasing the use of renewable and low carbon sources. Considering decarbonization projections, the share of renewable energy sources in energy balances is projected to increase. Slovenia also maintains projects of common interest, including electricity clusters with high voltage power lines with Croatia, Hungary and Italy, which will contribute to the optimization of electricity trade, energy supply and increase electricity interconnectivity. Moreover, the Slovenian and Croatian electricity transmission network operators are implementing a project of common interest in the field of smart networks, which is co-financed by Connecting Europe Facility.

  1. Estimated available energy

Slovenia has limited energy reserves (see Table 1). The proven and recoverable reserves of low quality brown coal and lignite amount to approximately 371 million tonnes. There are no proven recoverable reserves of crude oil or natural gas liquids. The estimated hydropower reserves of Slovenia are up to 9.1 TWh per year, of which 4.3 TWh are already exploited. The country is connected to three gas pipelines, from Algeria, Austria and the Russian Federation.


Fossil fuels Nuclear Renewables
Solida Liquidb Gasc Uraniumd Hydroe
Total amount 371 f f 1700 9100

a Coal, including lignite (million tonnes).

b Crude oil and natural gas liquids (million tonnes; oil shale, natural bitumen and extra heavy oil are not included).

c Natural gas (billion cubic metres).

d Reasonably assured resources under US $130/kg U (tonnes).

e Hydropower (TWh per year): technically exploitable capability, the amount of the gross theoretical capability that can be exploited within the limits of current technology.

f —: data not available.

Source: World Energy Council, data for 2015 [1].

  1. Energy Consumption Statistics

Total primary energy supply (TPES) in 2019 amounted to 283.2 PJ and in the 2000–2019 period increased at an average rate of 0.3% per annum. Final energy consumption (FEC) in 2019 amounted to 205.4 PJ and in the period 2000–2019 increased at an average rate of 0.5% per annum. The highest growth was recorded by electricity at 1.5% per annum, followed by renewable energy sources (1.4% p.a.), while a negative trend was recorded by solids (–2.3% p.a.) and heat (–0.5% p.a.).


Final Energy consumption [PJ] 2000 2005 2010 2015 2019 Compound
annual growth
rate 2000–2019 (%)
Total 194 216 218 200 210 0.42
Coal, Lignate and Peat 4 4 2 2 2 -3.58
Oil 98 105 107 94 97 -0.05
Natural gas 29 33 29 24 25 -0.78
Bioenergy and Waste 18 19 27 25 27 2.16
Electricity 38 46 43 46 49 1.35
Heat 8 8 9 9 10 1.18

*Latest available data, please note that compound annual growth rate may not be representative of actual average growth.

**Total energy derived from primary and secondary generation sources. Figures do not reflect potential heat output that may result from electricity co-generation.

—: data not available.

Source(s): United Nations Statistical Division, OECD/IEA and IAEA RDS-1

The sectorial analysis of FEC over the period 2000–2019 shows an increasing trend in the transport sector, atan average rate of 2.6% per annum, and in the industry sector (0.4% p.a.), while there was a decreasing trend in the household sector (–0.7% p.a.) and other use (–0.9% p.a.). A significant share of Slovenian industrial production is energy intensive, such as steel production, aluminium, chemicals, pulp or paper and building materials. Overall energy demand is decreasing gradually; in 2019 industrial energy demand accounted for 29% of final energy consumption.


  1. Electricity system and decision making process

The following services are considered public service obligations: transmission system operator, distribution system operator, electricity distribution and market operator. The transmission and distribution companies are required to ensure access to the electricity network in a transparent and non-discriminatory manner following the principles of regulated third party access. The information on transmission and distribution networks traffic is public. The markets for electricity and gas in Slovenia were opened to all non-household customers in July 2004, representing a volume of market opening of 75% and 90%, respectively. Both markets have been fully open since 1 July 2007.

The creation of a market operator is one of the obligatory elements of the Energy Act, and one of the fundamental conditions for opening up the electricity market. The operation of the organized electricity market and the rights and duties of the market operator were set in detail in the new Rules on the Operation of the Electricity Market in 2019, which implement the requirements of the first stage of harmonization of the Electricity Balancing Guideline Regulation. Borzen was established in 2001 as power market operator to implement the public utility service relating to the organization of the electricity market and activities in the Slovenian energy field connected with stimulating the use of renewable sources and the efficient use of energy. Borzen provides and facilitates the coordinated operation of the Slovenian electricity system. It is responsible for executing activities relating to balance scheme management, recording of closed contracts, elaboration of indicative operating schedule, imbalance settlement and financial settlement of transactions.

Within the ‘Centre for RES/CHP support’, Borzen acts as support scheme operator for the generation of energy from renewable energy sources (RES) and highly efficient cogeneration of heat and power (CHP). The support scheme is financed via a supplement to the electricity price. Installations using renewable energy sources or waste and cogeneration units are eligible for qualified producer status. Yet, producers must meet environmental acceptability standards. Power plants are divided into four groups, depending on the installed power: micro power plants (up to 50 kW); small power plants (from 50 kW to 1 MW); medium power plants (from 1 MW to 10 MW); and large power plants (above 10 MW). The feed-in tariff scheme and premium schemes are set by the Government to stimulate production of electricity from renewable energy sources and combined heat and electricity power plants.

Borzen also promotes the development of the Slovenian electricity market and market mechanisms in accordance with European Union guidelines and contributes significantly to the proper functioning of the Slovenian power system, alignment of Slovenian and European legislation and integration of the Slovenian electricity market with the European electricity market.

In accordance with the provisions of the legislation, the Energy Agency is established as the national energy regulator and is responsible for the preparation and compliance of market rules. The regulator’s tasks are to provide the conditions for the development of competitiveness and to ensure energy market operation by taking into account the requirements for sustainable, reliable and high quality supply.

The Energy Agency shall, acting under public authorization, carry out the administrative and other tasks specified in the Energy Act, European Union regulations, which determine the competences of the national energy regulators, or in general act of the agency adopted on the basis of the energy legislation. The tasks can be summarized in the following areas:

  • Regulating network activities, which covers economic regulation of all electricity and gas system operators and the regulation of the network with respect to issuing consents to the general acts;

  • Regulating the supply of heat and other energy gases;

  • Ensuring a reliable supply of natural gas;

  • Promoting the production of electricity from renewable sources and cogeneration;

  • Promoting the efficient use of energy;

  • Monitoring the electricity and natural gas market;

  • Supervising the providers of energy operators’ activities;

  • Protecting the rights of consumers.

The Energy Agency, in performing its tasks, establishes conditions that encourage regulated companies to improve performance and investments. It supervises and monitors the implementation of regulated activities by determining the right balance between the quality of supply and prices for regulated services and promotes the efficient use of existing infrastructure. It ensures the transparency and openness of the regulatory process. It cooperates in the preparation and amendment of the rules and general acts regulating market operation, and promotes transparency and non-discrimination.

The Energy Agency is continuously improving the regulation of the energy market in accordance with best professional practice. It participates in the creation of the internal energy market at a regional level.

1.2.1. Structure of electric power sector

Slovenia has diversified primary sources for electricity production. In 2019, Slovenia had 3820 MW of total installed electricity capacity, 688 MW of which was provided by Krško NPP, 1351 MW by hydropower plants, 1512 MW by thermal power plants and 269 MW by solar and wind power plant facilities (see Table 3).


Electricity production (GWh) 2000 2005 2010 2015 2019 Compound
annual growth
rate 2000–2019 (%)
Total 13 624 15 117 16 440 15 100 16 103 0.88
Coal, Lignate and Peat 4 611 5 271 5 288 4 385 4 434 -0.21
Oil 55 42 8 17 12 -7.70
Natural gas 293 339 548 404 544 3.31
Bioenergy and Waste 70 120 223 275 299 7.94
Hydro 3 834 3 461 4 703 4 091 4 683 1.06
Nuclear 4 761 5 884 5 657 5 648 5 821 1.06
Wind 0 0 0 6 6
Solar 0 0 13 274 303

*Latest available data, please note that compound annual growth rate may not be representative of actual average growth.

**Electricity transmission losses are not deducted.

—: data not available.

Source: United Nations Statistical Division, OECD/IEA and IAEA RDS-1

Total gross electricity production in 2019 amounted to 16100 GWh, of which 5821 GWh was produced from the nuclear power plant, 4683 GWh from hydropower plants, 5287 GWh from thermal power plants and 303 GWh from solar and wind power plants.

In Slovenia, there are eight power-generating companies, each with one main power station, with the exception of hydropower, where one company operates a chain of power plants on a single river system. Most of the major players in electricity production are owned by the two parent companies, Holding Slovenske Elektrarne (HSE) and GEN energija. HSE also has majority ownership of the lignite mine in Velenje. Nuklearna Elektrarna Krško (NEK), on the other hand, is owned equally by the Slovenian and Croatian legal successors of the founders of the power plant. On the Slovenian side, this is the company GEN energija, which is 100% state owned.

The electric power transmission network of Slovenia is operated by Slovenian Electric Utilities (ELES), whose main responsibility is to ensure the best possible and most transparent management of the existing transmission grid, operational reliability and security (as defined in the Energy Act). The Slovenian electric power system is interlinked with the synchronous transmission grids of neighbouring States and integrated with the European network. There are three voltage levels in the transmission grid (400 kV, 220 kV and 110 kV), as well as corresponding transformer substations. The transmission network of Slovenia is presented in Fig. 1, along with generating capacities.

FIG. 1. Transmission network of Slovenia.

  1. Main indicators

Total primary energy supply (TPES) in 2019 amounted to 283.2 PJ and was 1.8% lower than the year before. Due to an increase in imports of liquid fuels, the total energy dependence increased, amounting to 51.5% in 2019, and over the period 2000–2019 increased at an average rate of 0.3% per annum.

Final energy consumption (FEC) in Slovenia in 2019 amounted to 205.4 PJ. In recent years, FEC has been slowing down, so that in 2019 negative growth was recorded (–3.8%). The average annual growth of FEC/capita for the period 2000–2019 is 0.2%.


2000 2005 2010 2015 2019 Annual av. growth rate
2000–2019 (%)
Energy dependency (%) 50.4 50.1 47.9 48.1 51.5 0.3
TPES (GJ/capita) 137.1 156.1 148.2 133.2 136.1 0.0
FEC (GJ/capita) 95.6 107.1 103.0 96.2 98.7 0.2
Electricity consumption (kWh/capita) 5413 6425 5893 6250 6573 1.1
Energy intensity TPES/GDP (toe/M EUR 2010) 234 225 199 177 156 –2.1
Energy intensity TFC/GDP (toe/M EUR 2010) 168 161 142 129 115 –2.0
Nuclear/Total electricity (%) 34.9 38.9 34.4 37.4 36.2 0.4
RES overall share (%) na 19.8 21.1 22.9 22.0 1.3
Annual capacity factor (%)
Total 59.1 57.7 58.8 51.3 48.1 -0.9
Thermal 51.5 48.6 54.9 51.2 39.9 -0.9
Hydro 50.9 40.3 42.8 36.1 39.6 0.5
Nuclear 82.8 102.4 97.0 93.7 96.6 1.2

*Latest available data.

Source: RDS-1 and RDS-2

—: data not available.

Reducing energy intensity because of more efficient energy use and changes in energy use structures increases the competitiveness of the economy and ensures the security of the energy supply, reducing greenhouse gas emissions and promoting the development of the market with high energy efficient technologies.

In Slovenia, in the period 2000-2019, gross domestic product (GDP) increased at an average rate of 2.4% per annum, energy supply (TPES) increased by 0.3% per annum, and end use (TFC) by 0.5% per annum. The difference in growth rates is the reason why the energy intensity of energy supply (energy intensity TPES/GDP) decreased in this period at an average annual rate of 2.1%, and the energy intensity of end use (energy intensity TFC/GDP) decreased at an average annual rate of 2.0%.

Electricity consumption has been increasing in the last decade and amounted to 6573 kWh/capita in 2019, while the average annual growth for the period 2000–2019 was 1.1%. In 2019 nuclear energy accounted for 36.2% of total gross electricity production and in the period 2000–2019 increased at an average rate of 0.4% per annum.



  1. Overview

Slovenia has one nuclear power plant in commercial operation, Krško NPP. Construction started in 1975 and it was connected to the grid in 1981, entering commercial operation in 1983. In 2001, its steam generators were replaced, and the plant was first uprated by 6%, followed by an additional 3% uprate. The original plant lifetime was 40 years, based on economic parameters. Based on its good technical condition and the fact that all essential components were replaced and are well maintained. A 20 year lifetime extension (to 2043) was proposed, which would be adopted by regular ten year periodic safety review processes, first in 2023 and then in 2033. Krško NPP is a pressurized water reactor of 696 MW(e) net, delivered and constructed by Westinghouse and jointly owned with Croatia. The reliable operational and safety record of Krško NPP complies with all international standards and the highest safety requirements. The safety status of the plant is supervised by the Slovenian Nuclear Safety Administration (SNSA) as well as by international expert missions organized by the IAEA, the European Union and the World Association of Nuclear Operators (WANO), among others.

After modernization in 2001 and transition to an 18 month fuel cycle in 2005, Krško NPP can produce over 6 TWh in a year without outage and around 5.4 TWh in a year with outage.In accordance with the bilateral treaty on Krško NPP, between 2.7 TWh and 3 TWh of electricity is available for the Slovenian market annually. In addition to the share of the electricity produced, Krško NPP is also characterized by extremely high reliability. It can operate for 510 days without shutdown, ensuring stability of the electrical power system and a reliable supply to customers.

The contract between the governments of Slovenia and Croatia on the regulation of status and other legal relations connected to investment in Krško NPP, the use and decommissioning of the NPP, in addition to the memorandum of association, all took effect on 11 March 2003. The basic capital of Krško NPP is divided into two equal shares owned by the partners GEN energija and HEP (Hrvatska Elektroprivreda). Krško NPP produces and supplies electricity exclusively in favour of the two partners, who each have the right and obligation to 50% of its total output.

  1. Current organizational structure

The organizational structure of Krško NPP is shown in Figs 2 and 3.

FIG. 2. External organizational structure.

FIG. 3. Organizational structure of the Krško nuclear power plant.


  1. Status and performance of nuclear power plants

Table 5 provides the status of Krško NPP, and more data can be found on the Krško NPP home page ( (see Fig. 4).


Reactor Unit Type Net
Status Operator Reactor
First Grid
KRSKO PWR 688 Operational NEK WH 3/30/1975 9/11/1981 10/2/1981 1/1/1983 99.5
Data source: IAEA - Power Reactor Information System (PRIS).
Note: Table is completely generated from PRIS data to reflect the latest available information and may be more up to date than the text of the report.

Fig. 4. Location of Krško nuclear power plant.

The most important performance indicators are displayed in Table below.


Av. (1983–2020)
Availability (%)
Capacity factor (%)
Gross production (GW·h)
No. automatic fast shutdowns
No. manual fast shutdowns
No. unplanned normal shutdowns
No. planned normal shutdowns
No. event reports
Duration of the refuelling outage (days)

  1. Plant upgrading, plant life management and licence renewals

Krško NPP’s operational life was originally designed for 40 years, until 2023. However, because of reliable maintenance and the replacement of major vital components, Krško NPP is in good condition. Based upon these parameters, Krško NPP launched its ageing management programme in 2008, which serves as a basis for plant life extension. On 20 June 2012, the SNSA issued a decision approving the modifications, which will enable long term operation of Krško NPP. An approved ageing management programme of Krško NPP is a precondition for the extension of its operation beyond 2023. In addition, a comprehensive second periodic safety review was approved in 2013, and a third one will be conducted between 2021 and 2023.

Following the Fukushima Daiichi accident, Krško NPP analysed lessons learned and prepared the Safety Upgrade Programme (SUP), which was approved by the SNSA. The SUP for Krško NPP consists of a series of safety improvements, such as installing alternate bunkered systems for injecting cooling water into primary and secondary systems, installing an alternate system for cooling the spent fuel pool, installing a filtered venting system, replacing active hydrogen recombiners with passive ones, installing an emergency control room and independent instrumentation qualified for severe accidents, enhancing flood protection of the plant, etc. The SUP for Krško NPP, which is still under way, is scheduled to be completed before the end of 2021.

Furthermore, the preconditions for operation after 2023 include maintenance of operating equipment, well trained operators and a good safety culture among all employees. All of the above mentioned conditions should be fulfilled if operation of the NPP is to be extended beyond 2023.


Slovenia has started the development of several strategic documents in the field of nuclear energy. The latest National Energy and Climate Plan (NECP) from February 2020 in accordance with Resolution on the Slovenian long-term strategy 2050 (ReDPS50) adopted in July 2021 enables the lifetime extension of existing Krško NPP and comprehensively examine the possibility of long-term use of nuclear energy with a decision on the construction of a new NPP to be taken until 2027.


There are no domestic suppliers of NPPs in Slovenia. The only plant is Krško NPP, based on imported technology provided by the United States of America.


Krško NPP is owned in equal share by GEN energija (Slovenia) and HEP (Croatia). Krško NPP is responsible for its own safe and stable operation through a permanent commitment to nuclear safety following state of the art standards. Maintenance is covered by Krško NPP staff, while for other major activities and outages, external companies (domestic and foreign) are hired. All Krško NPP operators must pass an extensive training programme. Training consists of four phases over the course of about two years. The first phase includes a theoretical basis, the second includes Krško NPP systems, the third requires full scope simulator training and the fourth qualifies newcomers for independent work in the control room. Once candidates complete all phases, they are still required to pass the exam before the expert committee of the SNSA.


The 2003 Agreement between Slovenia and Croatia on Krško NPP required the preparation of a Decommissioning Programme for Krško NPP by the Slovenian and Croatian authorities for the management of radioactive waste. In accordance with the agreement, a review of the Programme for the Decommissioning of Krško NPP and Disposal of Low and Intermediate Level Waste and Spent Fuel was prepared in April 2004. An update of the Decommissioning Programme is required at least every five years.

A revision of the Decommissioning Programme was started in September 2008. At the 13th session of the Intergovernmental Commission in September 2019, the final version (third revision) of the Krško NPP Decommissioning Programme was agreed upon by the Intergovernmental Commission. The Programme was deemed suitable for further admission procedures in the Republic of Slovenia and the Republic of Croatia. The third revision of the Decommissioning Programme was approved by the Intergovernmental Commission in July 2020.

The third revision of the Krško NPP Decommissioning Programme was prepared according to the decommissioning strategy (‘Immediate Dismantling’) after its planned final shutdown in 2043, with results based on the planned 6th Revision of the Preliminary Decommissioning Plan for Krško NPP. It contains the operation of the spent fuel dry storage (SFDS) facility and its decommissioning, as well as the successive conventional demolition of the other remaining buildings. Two cases under this revision are considered: first, the base case considers that the SFDS will operate until 2103; second, the sensitivity case considers that the SFDS will operate until 2075.

For both cases, pre-decommissioning activities will start in 2040. In December 2043, final shutdown with decontamination and decommissioning approval is envisaged. Building structures will be cleared to field level in 2058. Under the base case, decommissioning of the SFDS is expected in 2104, with greenfield status achieved in 2107. Under the sensitivity case, decommissioning of the SFDS is expected in 2076, with greenfield status in 2079.

The waste treatment and disposal (e.g. availability of a final repository and the corresponding repository requirements) have an impact on the entire decommissioning project, and thus on the decommissioning costs. A decision on these is important to enhance the planning reliability process for the next revisions of the plan.


In Slovenia, high level radioactive waste includes spent nuclear fuel from Krško NPP and spent fuel from the TRIGA research reactor. The greatest amount of low and intermediate level radioactive waste (over 95%) is generated from the operation of Krško NPP. The remaining waste is produced from medicinal, industrial and research activities. A special category of waste involves spent sealed radioactive sources, which are in the possession of small holders or are stored at the Central interim storage facility for Radioactive Waste in the town of Brinje, near Ljubljana. Krško NPP is the main producer of all waste categories in Slovenia. The contribution of other producers is relatively small. The amounts of different categories of radioactive waste in Slovenia at the end of 2020 are given in Table below.


Volume/No. of fuel assemblies
Low and intermediate level
Krško NPP*
2303 m3
Central interim storage facility
89 m3
Spent fuel
Krško NPP
TRIGA reactor

* At different inside locations.

Figure 5 shows the accumulation of low and intermediate level radioactive waste in the Krško NPP storage area. Periodical volume reductions with compression, super compaction, incineration and melting are shown. The lower waste volume accumulation rate after 1995 is the result of a new in-drum system for drying evaporator concentrate and spent ion exchange resins. In 2006, Krško NPP started continuous compression of radioactive waste with its own super compactor installed at the storage facility.

FIG. 5. Accumulation of low and intermediate level radioactive waste in the Krško NPP storage area.

All spent fuel in Krško NPP is stored in the spent fuel pool, with 1694 cells. At the end of 2020, the total number of spent fuel assemblies in the spent fuel pool amounted to 1323 — including two special canisters with damaged fuel rods. The number of annually spent fuel assemblies and the total number of such elements in the pool are shown in Fig. 6.

FIG. 6. The number of annual spent fuel assemblies and the total number of such elements in the Krško NPP spent fuel pool.


  1. R&D organizations

The Jožef Stefan Institute (IJS) is the leading Slovenian research organization. It is responsible for a broad spectrum of basic and applied research in the fields of natural sciences and technology. The staff of around 800 is specialized in physics, chemistry and biochemistry, electronics and information science, nuclear technology, energy utilization and environmental science.

Since the beginning of domestic nuclear activities, research at the institute has also been oriented towards the field of nuclear physics and the use of nuclear energy for peaceful purposes. At the Reactor Centre in Podgorica, four institute research departments and several centres were established.

The Department of Low and Medium Energy Physics performs research on atomic and nuclear physics and is also engaged in radiological environmental protection, namely the regulation of nuclear facilities and the control of the level of radioactive substances in food and the environment. It was for this reason that the Ecological Laboratory, with its mobile unit, was established. The main research areas of the Reactor Physics Department are theoretical, experimental and applied reactor physics, plasma physics, nuclear fragmentation, neutron dosimetry, neutron radiography, the physics of semiconductor devices and oncology. The Reactor Engineering Division performs nuclear engineering and safety research covering the modelling of basic thermohydraulic processes, thermohydraulic safety analyses of the project and severe accidents, structural safety analyses and probabilistic safety analyses. The multidisciplinary research of the Department of Environmental Sciences focuses on the combination of reciprocal physical, chemical and biological processes that influence the environment.

The institute also operates a Nuclear Training Centre on its premises, completed in 1988. It provides training for Krško NPP personnel, organizes radiological protection courses and carries out public information activities. The centre also regularly organizes and hosts training activities and workshops for the IAEA. Their main activity is promotion of knowledge about the use of nuclear energy.

The Reactor Infrastructure Centre is also part of IJS. The main purpose of the centre is operation of a TRIGA Mark II research reactor for the needs of IJS and other research groups. The research reactor was built by IJS in 1966. The reactor was delivered by General Atomics, while the reactor tank and body were built by Slovenian companies. In 1991, it was reconstructed and equipped for pulse operation. Practically all nuclear professionals in Slovenia started their career or attended practical training courses at the TRIGA reactor (including all professors of nuclear engineering and reactor physics at Ljubljana and Maribor universities, as well as directors and key personnel of Krško NPP, the SNSA and the Agency for Radwaste Management. The reactor has accumulated more than 40 years of continuous operation without any failure of major equipment or any event violating safety standards. It is planned that the reactor will operate at least until 2026.

  1. Development of advanced nuclear power technologies

IJS has a long research programme tradition in the field of fission technology. The main efforts are dedicated to reactor physics and reactor technology. Research on reactor physics is directed mostly towards developing new methods for research and power reactor calculations. Work is carried out on neutron, photon and electron Monte Carlo transport, nuclear data evaluation, advanced nodal methods, pin cell and fuel element homogenization and on methods aimed at precise power distribution reconstruction. Also studied are advanced fourth generation reactors, advanced neutron sources and data and materials for fusion technology. The reactor technology research activities belong to the wider field of nuclear engineering and safety. This interdisciplinary research integrates thermohydraulic, structural and probabilistic safety analyses. Advanced reactor technology is also studied, mainly by developing computer models for different physical phenomena. Both reactor physics and technology divisions are strongly involved in research projects within the European Framework Programmes, as well as other programmes.

Slovenia is also very strongly involved in fusion research, mainly for the purposes of the ITER project. Different research departments deal with fusion, and all of them are associated with the Slovenian Fusion Association. The contributions of the institutions in the association to the several areas of the fusion programme are based on R&D experiences of researchers in the fields of nuclear, atomic and plasma physics, ceramic materials development, mechanical engineering and computer aided design. The major equipment available in the institutions includes the following: an ion beam accelerator with materials diagnostic installations; a TRIGA reactor; an advanced fully integrated high resolution microscope facility dedicated to nanostructural materials; and computer systems for simulations, structural mechanical analyses and computer aided design.

  1. International cooperation and initiatives

Slovenia was admitted to full membership of the IAEA in 1992. Cooperation with the IAEA covers a wide range of activities, including:

  1. Cooperation within of international conventions;

  2. IAEA missions to Slovenia;

  3. Technical cooperation, including attendance of Slovenian experts on IAEA sponsored seminars and training courses, scholarship, scientific visits and research contracts.

Furthermore, Slovenia cooperates with other international organizations, such as the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD/NEA — full member) and the European Union. Cooperation is also institutionalized through membership in associations, such as the Western European Nuclear Regulators Association (WENRA), the Network of Regulators of Countries with Small Nuclear Programmes (NERS) and the International Nuclear Law Association (INLA).

There is also cooperation through multilateral and bilateral international agreements. Krško NPP is also a member of WANO.


Until 2008, Slovenia did not have any dedicated undergraduate nuclear programmes, yet a few subjects related to the nuclear field were available at some universities. Domestically, those who were interested in nuclear engineering typically attended the University of Ljubljana (IJS and Faculty for Mathematics and Physics) or the University of Maribor (Faculty for Civil Engineering). Both graduate programmes are ongoing, and a number of nuclear experts have graduated from these programmes. The nuclear graduate programme of the University of Ljubljana is also a member of the European Nuclear Engineering Education Network (ENEN).

In 2007, the Faculty of Energy Technology was established at the University of Maribor, and the educational process started in the academic year 2008–2009. Altogether, more than 180 students signed up in the first academic year. The faculty offers both undergraduate and postgraduate programmes.

In addition to academic institutions, other expert institutions offer educational services in the field of nuclear technology. The most prominent includes the Nuclear Training Centre (ICJT), which is part of IJS. Its basic activities are Krško NPP staff training, radiation protection training, organization of international seminars and public information about nuclear technology.


One of the fundamental safety principles of the Ionizing Radiation Protection and Nuclear Safety Act is the publicity principle. The SNSA issues information on its activities to the public, including regulatory decisions and newsletters on safety matters relevant to the industry. The SNSA publishes a complete list of modifications implemented at Krško NPP, which contains the date and the description of the modification. The SNSA implements stakeholder communication as a process to ensure the public is routinely informed of its decisions.



  1. Regulatory authority(s)

In 1987, the Slovenian regulatory body was established by the Act on Amendments to the Act on Organization and Competence of the Regulatory Bodies and Republican Organizations and Independent Professional Services of the Slovenian Government.

Over the years, the organizational structure and linkages with other administrative bodies or ministries have changed, becoming more specific in function in recent years. Activity of the Slovenian Nuclear Safety Administration

The responsibilities of the SNSA are described in the decree on bodies affiliated with certain ministries. It performs specialized technical and developmental administrative tasks and inspections relating to:

  1. Nuclear and radiation safety;

  2. Radioactive waste management;

  3. Practices involving radiation and use of radiation sources, except in medicine or veterinary medicine;

  4. Protection of people and the environment against ionizing radiation;

  5. Physical protection of nuclear materials and facilities;

  6. Non-proliferation of nuclear materials and safeguards;

  7. Import, export and transit of nuclear and radioactive materials and radioactive waste;

  8. Radiation monitoring;

  9. Liability for nuclear damage.

The SNSA is a part of the Ministry of the Environment and Spatial Planning. The major nuclear facilities supervised by the SNSA are Krško NPP and the TRIGA research reactor at IJS. There is an interim storage area for low and medium radioactive waste at the Reactor Centre site operated by the ARAO. The closed uranium mine Žirovski Vrh is also supervised by the SNSA. Organization of the Slovenian Nuclear Safety Administration

The activities of the SNSA are performed in six organizational units:

  1. Nuclear Safety Division;

  2. Radiation Safety and Materials Division;

  3. Radiation and Nuclear Safety Inspection;

  4. Office of General Affairs;

  5. Office of International Cooperation;

  6. Emergency Preparedness Division.

The Nuclear Safety Division deals with licences, and leads analyses used to support licensing activities, by performing and/or reviewing the safety analysis.

The Radiation Safety and Materials Division verifies radiation safety (except in medicine or veterinary medicine) and is responsible for radiation safety and radiation monitoring. It also deals with the trade, transport and treatment of nuclear and radioactive materials. It shares responsibility in the field of physical protection of NPPs and nuclear materials with the Ministry of the Interior. It also deals with the treatment, temporary storage and disposal of radioactive waste, and participates in the administrative procedures for the selection of sites for nuclear facilities, especially those destined for radioactive waste. Finally, it is responsible for safeguards and illicit trafficking issues.

The Radiation and Nuclear Safety Inspection unit supervises licence holders in fulfilling the safety requirements stipulated in the legislation and in the licences. Inspections are performed based on a developed plan of inspections. To increase their efficiency, inspections may be unannounced. Inspections at Krško NPP are typically carried out on a weekly basis. The Office of General Affairs is involved with licensing procedures and the preparation of legislation on nuclear and radiation safety and on nuclear third party liability.

The Office of International Cooperation coordinates cooperation with international organizations (IAEA, OECD/NEA, WENRA, etc.) and with foreign regulatory authorities for nuclear and radiation safety within bilateral agreements.

The Emergency Preparedness Division is primarily responsible for planning, training, conducting drills and exercises in the area of emergency preparedness and response within the SNSA as well as for coordination of these activities with other stakeholders in Slovenia and abroad.

  1. Licensing process

The licensing process is governed by the provisions of the Ionizing Radiation Protection and Nuclear Safety Act (Off. Gaz. RS, 76/2017 in 26/19).

The licensing system is divided into four steps after the preliminary condition (the planning of the site of nuclear facilities in the national site development plan) is fulfilled:

  • Application for the licence for the use of land — the competent body is the Ministry of the Environment and Spatial Planning — with preliminary approval of radiation and nuclear safety — the competent body is the SNSA.

  • Application for the licence to construct a facility — the competent body is the Ministry of the Environment and Spatial Planning, with approval from the SNSA.

  • Application for the licence for trial operation — the competent body is the SNSA.

  • Application for operation and decommissioning — the competent body is the SNSA.

In the Ionizing Radiation Protection and Nuclear Safety Act, there are provisions on:

  • Use of land: The planning of the site of nuclear facilities and the conditions for their siting in a spatially and functionally contained area must be carried out with the national site development plan.

  • Construction: An investor intending to construct or decommission a nuclear facility must obtain a construction licence for the construction, reconstruction or decommissioning of the facility. The same applies to the investor intending to carry out construction work in an area of limited use due to the vicinity of a nuclear facility, which affects nuclear safety.

  • Trial operation: After construction work is completed, every nuclear facility must first undergo a period of trial operation. It is necessary to obtain approval from the SNSA prior to the commencement of a period of trial operation of a nuclear facility.

  • Operation and decommissioning: An investor or operator intending to commence or cease operation of a nuclear facility, commence the disposal of spent fuel in a repository of spent fuel or of radioactive waste in a repository of radioactive waste, close a repository of spent fuel or radioactive waste or commence or complete the decommissioning of a nuclear facility, must obtain a licence from the SNSA.

  • Periodic safety review (PSR): The act requires the operator of a nuclear facility to ensure regular, full and systematic assessment and examination of radiation or nuclear safety of a facility by means of a PSR. The PSR must be approved by the SNSA. The approved report on the PSR is the condition for renewing an operating licence.

  • Modifications: With regard to every intended modification in the facility or to the management method used or to the operation of the facility, including maintenance work, inspection, testing or the introduction of a technical, organizational or any other type of modification which affects or could indirectly affect the content of the safety analysis report, the operator must evaluate the intended modification in relation to its significance for radiation or nuclear safety. With respect to their significance for radiation or nuclear safety, changes may be:

    • Such that it shall be necessary only to notify the SNSA;

    • Such that the intention of their implementation must be reported to the SNSA;

    • Of such significance for radiation or nuclear safety that for its implementation a licence from the SNSA must be obtained.

The Ionizing Radiation Protection and Nuclear Safety Act contains provisions on issuing, renewal, amendment and expiration of the licence. The act determines the content of a licence, such as details about the operator, a detailed description of the type, scope and purpose of the use of the facility; the duration of the validity of the licence; the operational conditions and limitations relating to the safety analysis report; obligations relating to the periodic safety review; the steps the licensee must take after the licence expires; the financial warranties (if needed); the deadlines and conditions for a repeated review of the evaluation of the radiation protection of exposed workers and the protection and emergency plan; the duration of a licence (a licence may be issued for a maximum of ten years, except in the case of a licence for the completion of decommissioning of a facility or the closure of a facility); and the conditions for the renewal of the licence (the same conditions and procedure as for the issuing of a licence). A licence may be amended at the request of the licensee or ex officio. A licence can be amended ex officio when the conditions related to the nuclear or radiation safety have changed; when required for the protection of the environment or the life or health of the population; for public benefit; or when (owing to external influences or natural phenomena) a radiation source is under threat so that nuclear or radiation safety is considerably reduced. The provisions applying to the issue of a licence also apply to the procedure for amending a licence.

The Ionizing Radiation Protection and Nuclear Safety Act has only a few provisions on the licensing procedure, as the General Administrative Procedure Act stipulates all the general principles of the licensing procedure, which are to be followed also by the SNSA. The rules of the General Administrative Procedure Act must follow all procedural matters, except for cases when the special acts provide for a different solution. For example, based on the provisions of the General Administrative Procedure Act, the licensee can appeal any decision issued by any regulatory body. However, the Ionizing Radiation Protection and Nuclear Safety Act determines the cases for which no right to appeal against the SNSA’s decision is allowed. In these cases, the licensee will have only the right for judicial review of the decision.

Furthermore, for the implementation of the Ionizing Radiation Protection and Nuclear Safety Act, two rules have been issued by the Minister for the Environment which deal in detail with specific licensing aspects.

The Rule on Operational Safety of Radiation and Nuclear Facilities determines:

  • The method of using the operating conditions and limits;

  • The method and frequency of reporting on the implementation of programmes, on collection and analysis of operating experience;

  • The manner and extent of control of ageing;

  • The method of maintenance, testing and inspection of structures, systems and components.

The rule also has provisions on:

  • The content, scope and frequency of regular and emergency reporting;

  • The frequency, content, scope, duration and method of conducting periodic safety reviews and the manner of reporting on these reviews;

  • Cases when the SNSA may order a periodic safety review;

  • The content, quality and method of probabilistic safety analysis for checking the safety of nuclear facilities and the evaluation methodology and classification of modifications and the manner and form of information and notification of changes in radiation or nuclear facilities.

With respect to potential emergency situations, the rules also detail requirements on an emergency response plan and emergency management of radiation or nuclear facilities, on emergency procedures in radiation or nuclear facilities, and on ways of informing about the incident.

The Rule on Radiation and Nuclear Safety Factors determines the conceptual basis for radiation and nuclear facilities, the content of applications and of documents to obtain approvals and licences for nuclear and radiation facilities under the Ionizing Radiation Protection and Nuclear Safety Act. It also determines the content of safety reports and other documentation necessary to demonstrate and ensure the safety of radiation and nuclear facilities, as well as additional requirements regarding the organization of a radiation or nuclear facility and regarding the content and format of the quality assurance programme and its implementation in radiation and nuclear facilities.


In 2013, the National Assembly (Slovenian Parliament) adopted the Resolution on Nuclear and Radiation Safety in Slovenia from 2013 to 2023. Although the provisions of the IAEA safety standards are not legally binding, IAEA Safety Standards Series No. GSR Part 1 (Rev. 1), Governmental, Legal and Regulatory Framework for Safety [2], was the primary catalyst for the preparation of the resolution. The resolution represents a fundamental political orientation and commitment to nuclear and radiation safety as a priority in all other aspects of the use of nuclear technologies and ionizing radiation.

In 2016, the Slovenian Parliament adopted the Resolution on the National Programme for the Management of Radioactive Waste and Spent Fuel Management for the Period 2016–2025 (ReNPROG), replacing a similar resolution from 2006. This national programme is also the basis for the fulfilment of Art. 11 of Council Directive 2011/70/Euratom of 19 July 2011 on establishing a Community framework for the responsible and safe management of spent fuel and radioactive waste, which requires Member States to ensure the implementation of their national programme covering all types of spent fuel and radioactive waste under their jurisdiction and all stages of spent fuel and radioactive waste from generation to disposal.

The new Ionizing Radiation Protection and Nuclear Safety Act was adopted by the Parliament on 12 December 2017. The act was published in the Official Gazette of the Republic of Slovenia No. 76/2017, and entered into force on 6 January 2018. The new act adjusted policies to European Union legislation in the field of radiation and nuclear safety and to international agreements succeeded, ratified or signed by Slovenia. In 2019, the act was amended with some changes related to the field of security clearance and also with some additional minor (terminological) changes. The changes were published in the Official Gazette of the Republic of Slovenia No. 26/2019 in April 2019.

The act includes the main principles in the field of nuclear and radiation safety and provisions on:

  • Practices involving ionizing radiation (reporting an intention, a permit to carry out practices involving radiation, a permit to use a radiation source);

  • Protection of people against ionizing radiation (main principles, justification, dose limits, protection of exposed workers, medical exposure);

  • Radiation and nuclear safety (the classification of facilities; use of land; construction and carrying out of construction and mining activities; trial and actual operation of radiation and nuclear facilities; radioactive contamination; radioactive waste and spent fuel management; import, export and transit of nuclear and radioactive substances and radioactive waste; intervention measures);

  • Issuing, renewal, modification, withdrawal or expiration of a licensee;

  • Physical protection of nuclear facilities and nuclear substances;

  • Non-proliferation of nuclear weapons and safeguards;

  • Monitoring radioactivity in the environment;

  • Removal of the consequences of an emergency event;

  • Report on protection against radiation and on nuclear safety, records containing information on radiation sources and practices involving radiation;

  • Financing (costs incurred by the users and public expenses) and compensation for the limited use of land due to a nuclear facility;

  • Inspection, penal provisions and transitional and final provisions.

In its transitional provisions, the act provides for the issuing of several decrees of the Government and rules of the competent ministries.

The new Act on Liability for Nuclear Damage was published in the Official Gazette of the Republic of Slovenia No. 77/2010 on 4 October 2010. The act governs the liability for nuclear damage resulting from the use of nuclear energy for peaceful purposes, insurance of liability for nuclear damage and the procedure for claiming compensation for nuclear damage.

The act on the one hand follows the provisions of the revised Paris Convention (Protocol of 2004 to Amend the Paris Convention on Third Party Liability in the Field of Nuclear Energy of 29 July 1960, as amended) that are covered,raised liability amounts for compensation, and extended prescription and extinction periods for nuclear damage claims.

On the other hand, the act clearly sets only one court which shall be competent to rule on compensation for nuclear damage and includes a number of provisions regarding rules of procedure of claiming compensation and the distribution of compensation. Public funds, provided by the State, shall be provided in the budget; the amount, manner and dynamics of the drawings of such public funds shall be determined by interventional law, which would follow any eventual significant accident. Regarding those risks which nuclear insurers are unwilling or unable to cover, the act provides for conclusion of a premium based insurance agreement between the Government and the operator, but such an arrangement is limited in time (until the situation on the domestic and international insurance market changes, but no longer than four years). The act also prescribes all necessary provisions which ensure its compliance with the 2004 Protocol to Brussels Supplementary Convention.

It should be mentioned that Slovenia is a party to all relevant international treaties and conventions in the area of nuclear and radiation safety (see Appendix I).

For the current legislation in the area of nuclear and radiation safety, see the SNSA web page:


[1] WORLD ENERGY COUNCIL, World Energy Resources 2016, WEC, London (2016).

[2] INTERNATIONAL ATOMIC ENERGY AGENCY, Governmental, Legal and Regulatory Framework for Safety, IAEA Safety Standards Series No. GSR Part 1 (Rev. 1), IAEA, Vienna (2016).


Slovenia is party to the following treaties:

Agreements with the IAEA
Amendments of Article VI & XIV.A of the IAEA Statute
3 April 2000
Non-Proliferation Treaty related agreement INFCIR/538
Entered into force
1 August 1997
Additional protocol
Entered into force
22 August 2000
Improved procedures for designation of safeguards inspectors

Supplementary agreement on provision of technical assistance by the IAEA
10 May 2006
Agreement on privileges and immunities
21 September 1992
Other relevant international treaties
Treaty on the Non-Proliferation of Nuclear Weapons
7 April 1992
Treaty on the Prohibition of the Emplacement of Nuclear Weapons and other Weapons of Mass Destruction on the Sea Bed and the Ocean Floor and in the Subsoil
7 April 1992
Treaty Banning Nuclear Weapons Tests in the Atmosphere, in Outer Space and under Water
7 April 1992
Convention on Physical Protection of Nuclear Material
25 June 1991
Convention on Early Notification of a Nuclear Accident
25 June 1991
Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency
25 June 1991
Paris Convention on Third Party Liability in the Field of Nuclear Energy
16 October 2001
Brussels Supplementary Convention to the Paris Convention
Entered into force
5 June 2003
Joint protocol
Entered into force
27 April 1995
Protocol to Amend the Vienna Convention on Civil Liability for Nuclear Damage
Not signed

Convention on Supplementary Compensation for Nuclear Damage
Not signed

Convention on Nuclear Safety
Entered into force
18 February 1997
Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management
Entered into force
18 June 2001
Comprehensive Nuclear-Test-Ban Treaty
31 August 1999

Zangger Committee

Nuclear Suppliers Group

Nuclear Export Guidelines

Acceptance of NUSS Codes


Responsible ministry for the nuclear energy programme
Ministry of Infrastructure
Langusova ulica 4
1535 Ljubljana, Slovenia
Tel.: +386 1 478 80 00
Fax: +386 1 478 81 39
National Atomic Energy Authority
Slovenian Nuclear Safety Administration
Ministry of the Environment and Spatial Planning
Litostrojska cesta 54
1000 Ljubljana, Slovenia
Tel.: +386 1 472 1100
Fax: +386 1 472 1199
Agency for Radioactive Waste Management
Litostrojska cesta 58A
1000 Ljubljana, Slovenia
Tel.: + 386 1 236 32 00
Fax: + 386 1 236 32 30
Nuclear research institutes
Institute ‘Jožef Stefan’
Jamova cesta 39
1000 Ljubljana, Slovenia
Tel.: +386 1 477 39 00
Fax: +386 1 251 93 85
Institute ‘Jožef Stefan’
Reactor Centre Podgorica
Brinje 40
1262 Dol pri Ljubljani, Slovenia
Tel.: +386 1 588 5450
Fax: +386 1 588 5377
Energy research institute
Milan Vidmar Institute for Power Economy and Electrical Industry
Hajdrihova 2
1000 Ljubljana, Slovenia
Tel.: +386 1 474 36 01
Fax: +386 1 425 33 26
Other nuclear organizations
Krško NPP
Vrbina 12
8270 Krško, Slovenia
Tel.: +386 7 48 02 000
Fax: +386 7 4921 006
Slovenian Electric Utilities — ELES
Hajdrihova 2
1000 Ljubljana, Slovenia
Tel.: +386 1 474 3000
Fax: +386 1 474 2502
Milan Copic Nuclear Training Centre
Institute ‘Jožef Stefan’
Jamova 39, 1001 Ljubljana, Slovenia
Tel.: +386 1 588 52 98
Fax: +386 1 588 53 76
Nuclear Society of Slovenia (NSS)
Jamova 39
1001 Ljubljana, Slovenia
Tel.: +386 1 5885 450
Fax: +386 1 5885 377
Other organizations
University of Ljubljana
Kongresni trg 12
1000 Ljubljana, Slovenia
Tel.: +386 1 241 85 00
Fax: +386 1 241 86 60
University of Maribor
Slomškov trg 15
2000 Maribor, Slovenia
Tel.: +386 2 23 55 280
IJS Science Information Centre
Jamova 39
1000 Ljubljana, Slovenia
Tel.: +386 1 47 73 304
Fax: +386 1 47 73 152
Ljubljana Technology Park
Tehnološki park 19
1000 Ljubljana, Slovenia
Tel.: +386 1 620 34 00
Fax: +386 1 620 34 09

Coordinator information

Gregor Plavcak

Ministry of Infrastructure

Langusova 4

1535 Ljubljana



Darko Pavlin

Slovenian Nuclear Safety Administration

Litostrojska cesta 54

1000 Ljubljana