(Note: the following information was provided by the Country Coordinator for Slovenia)
The Republic of Slovenia has a small nuclear programme; one operating nuclear power plant, one research reactor and one central interim storage facility for radioactive waste from small producers. In addition, there is also an uranium mine and mill in the decommissioning stage at Žirovski vrh.
The Republic of Slovenia has no operational facility for final disposal of radioactive waste or spent nuclear fuel.
The Krško Nuclear Power Plant (Krško NPP) is one of the main pillars of the Slovenian power system. It is situated on the left bank of the Sava River in the south-eastern part of Slovenia. It is a Westinghouse two-loop Pressurised Water Reactor with nominal output power 727/696 MWe (gross electrical power/net electrical power). It is designed to operate until the end of 2023. The plant is owned by state-owned Slovenian and Croatian electrical power companies, GEN energija d.o.o. and Hrvatska Elektroprivreda d.d., respectively. It is operated by the public enterprise Krško NPP d.o.o. The Krško NPP is the major producer of radioactive waste in the Republic of Slovenia. As part of the technological process of electricity production, all operational radioactive waste and spent nuclear fuel are stored within the plant area. Solid radioactive waste is treated and then packed into steel drums, which are then stored in the solid radwaste storage facility.
The Jožef Stefan Institute Reactor Infrastructure Centre (IJS Reactor Infrastructure Centre) is a part of the Jožef Stefan Institute (IJS). One of the activities of the centre is operation of the TRIGA Mark II research reactor for the needs of IJS and other research groups. The TRIGA Mark II research reactor is a General Atomic open-pool type research reactor with the thermal power of 250 kW. It was initially licensed in 1966 and was re-licensed for steady state and pulse operation after renovation and reconstruction in 1991. The facility is used in research projects, for the production of isotopes for medicine and industry as well as for education.
Fuel elements are kept in the reactor building of the IJS Reactor Infrastructure Centre. Two spent fuel pools are part of the TRIGA Mark II research reactor. The first spent fuel pool was constructed with the reactor in 1966 and is no longer in use. The second one was constructed in 1992. Its capacity is 195 spent fuel elements. All spent fuel has been shipped back to its origin (USA) in 1999 (total 219 fuel elements). In 2007, 10 fresh fuel elements were sold to the French company AREVA and shipped to France. The total number of the remaining fuel elements at the reactor is 84.
In addition the reactor produces a minor amount of low and intermediate level waste (LILW). The integral part of the IJS Reactor Infrastructure Centre is a hot laboratory, which is among others licensed also for treatment of radioactive waste from small producers. In January 2008 it was decided that the reactor shall terminate the operation in 2016.
The Central Interim Storage for Radioactive Waste in Brinje, situated at the IJS Reactor Infrastructure Centre, is intended for storage of low and intermediate level radioactive waste arising from medical, industrial and research applications. The construction of the facility started in 1984 and it was put into operation in 1986. In 1999, the responsibility for managing and operation of the interim storage was transferred from the IJS to the Agency for Radwaste Management (ARAO). Following the refurbishment and two and a half years of trial operation, a new operating license was issued in early 2008 for the period of 10 years.
The Žirovski vrh Uranium Mine was in operation in the period from 1984 to 1990. The Žirovski vrh Uranium Mine terminated its regular operation in 1990. The decision to close it was influenced by economic reasons, since the uranium production was no longer economically competitive. In 1992, the Republic of Slovenia, as the owner of the Žirovski vrh Uranium Mine, established a company called Žirovski vrh Mine d.o.o. to perform the permanent closure of the mine. The uranium mill is decommissioned and the resulting wastes are disposed of on the mining waste disposal site Jazbec. The remediation work on both disposal sites is nearly completed.
In 2003 Agreement between the governments of Slovenia and Croatia on the status and other legal issues related to investment, exploitation, and decommissioning of the Nuclear power plant Krško was ratified by both sides.The Agreement states that location of NPP Krško could be used as temporary storage for RW and SF during the plant lifetime. If contracting parties do not achieve agreement on common solution for RW and SF management during the planned lifetime of NPP Krško, they undertake that two years after that period at the latest they will finish removal and takeover of RW and SF from the location of NPP Krško, half by each side. In that case, contracting parties will individually bear the costs of RW and SF management activities.
Both contracting parties will regularly contribute into special national funds in the amount estimated in jointly prepared programs. Each fund will finance half of all the activities related to decommissioning of NPP Krško and to joint management of RW and SF.
The first decommissioning plan and costs estimate for the NPP Krško was prepared in 1995-1996 by Slovenia alone, prior to the Agreement. 1st revision of Programme of NPP Krško Decommissioning and SF & LILW Disposal, Revision 1 (DP Rev.1) was completed in the first half of 2004. 2nd Revision of DP was prepared in 2010 but it is still under revision.
DP Rev. 1 recommended an integrated scenario of the NPP decommissioning and joint RW & SF management which foresees that decommissioning activities will begin immediately after the NPP shut down in 2023 and will be completed by 2036. One LILW repository (either in Slovenia or in Croatia) would be built; it would operate from 2018 until 2037, and then would be closed in 2042.
In DP Rev. 2 several modifications of this basic variant of LILW repository were made due to different reasons:
- The influence of the results of Preliminary Decommissioning Plan for the NPP KRSKO (PDP) study and the predicted LILW volumes. The assessed LILW volumes are significantly lower than from DP Rev.1, used in preliminary design which accounts for 1400 disposal containers in case of half LILW from NPP Krško (2 silos) or for 2.800 disposal containers in case of all NPP Krško LILW (4 silos).
- Accepted modifications of boundary conditions as adopted by Inter-Governmental Committee and which effect the variants of LILW repository:
- it was decided to evaluate scenarios based on two options of NPP Krško operation - with presently planned NPP Krško lifetime until 2023 and with lifetime extension until 2043.
- DP should analyze two possible options of LILW disposal:
- all LILW from NPP Krško will be disposed of in one repository, either in Slovenia or in Croatia; and
- only Slovenian share of LILW from NPP Krško will be disposed of in Slovenian repository, the LILW waste will be divided, a standard surface vault -type will be analyzed as more appropriate for Croatia.
- The LILW repository should be in operation in 2018 or other possible period, depending on the NPP Krško life extension. Start of LILW repository operation in 2013 is removed as not feasible.
SF would be removed into a dry storage facility (available from 2023, on unspecified location), where it would be kept for about 45 years, until disposal or export into a third country. In case of disposal, one joint deep geological repository (either in Slovenia or in Croatia) would be operating in 2068-2077, and would be closed 5 years later. The independent dry SF storage facility would allow for some timing flexibility, including a few decades of waiting time before decision on SF export or disposal must be made.
The Resolution on the 2006-2015 National Programme for Managing Radioactive Waste and Spent Nuclear Fuel (the Programme), which was adopted by the Slovenian Parliament in March 2006, is one of the key documents in the field of radioactive waste management. In the Programme, LILW management is treated as an integral process, covering all stages from waste generation to waste disposal. Different current and near-future radioactive waste streams and waste arising are taken into account, considering the present and the planned waste management practices. Besides radioactive waste from the Krško NPP also other small producers (medicine, industry, research) and other activities with radioactive waste are described. The Programme includes the analysis of measures for minimisation of radioactive waste production, its treatment, and its conditioning before disposal.
The limited storage capacities at nuclear facilities call for decisions and practical solutions. The construction of a repository for short-lived LILW is one of the principal goals of LILW management in Slovenia. The site for the disposal of LILW has already been decided (Vrbina in municipality Krško).
In order to meet the provision of the Programme in January 2008, the IJS made a decision to terminate the operation of the TRIGA Mark II research reactor in 2016 and to return all its spent and remaining fresh fuel to the USA, within the frame of the USA research reactor spent fuel return programme, by the year 2019.
The Agency for Radwaste Management (ARAO) is a non-profit organisation of the Slovenian Government which provides a state-owned public service for radioactive waste management. It is financed through the national budget and partially through the Fund for the Decommissioning of the Krško NPP.
ARAO has the responsibility of collecting, transporting, treating, storing and disposing of LILW, coming from the small producers in the Republic of Slovenia. It also has the responsibility of disposal of all radioactive waste coming from the operators of nuclear and radiation facilities, when applicable. All activities are made transparent to the public through annual reports, the internet and other outreach activities.
Slovenian Nuclear Safety Administration (SNSA) is a regulatory body with a mission to prevent or mitigate harmful effects of ionising radiation to workers, population and environment, and to assure use of nuclear energy for peaceful purposes only. Its scope of competence includes carrying out administrative and professional tasks and regulating:
- nuclear and radiological safety of nuclear facilities, nuclear trade, transport and handling of nuclear and radioactive materials, accountability and control of nuclear materials,
- physical protection of nuclear facilities and nuclear materials liability for nuclear damage, professional qualifications of personnel operating nuclear facilities and their training,
- quality assurance in nuclear field,
- radiological monitoring of the environment,
- early notification in case of nuclear or radiological accidents, and
- international co-operation in the field of competence.
During the operation of the Krško NPP, various radioactive substances in liquid, gaseous and solid form are generated. Radioactive substances are collected, segregated and processed to obtain a final form for storing in the plant’s radioactive waste storage locations. These radioactive substances are processed in a system for radioactive waste treatment. The system is constructed for collecting, processing, storing and packaging of waste in a suitable form to minimize releases into the environment. Three fundamental systems are used for radioactive waste management, namely for liquid, solid and gaseous radioactive waste.
Liquid radioactive waste arising from all sources during the operation of the Krško NPP is processed by the Liquid Waste Processing System consisting of tanks, pumps, filters, an evaporator and two demineralizers. This system is designed to collect, segregate, process, recycle, and discharge liquid radioactive waste. The blow-down water from the steam generators is purified separately. The radioactivity of the water discharged into the Sava River is substantially lower than the maximum permissible concentration.
All solid radioactive waste generated during plant operation, maintenance activities and servicing, is collected in the Solid Radioactive Storage Facility. Solid waste is compressed and encapsulated in standard-size 208 l stainless steel drums. These drums are presently stored in the Solid Radwaste Storage Facility within the plant area. The solid radioactive waste processing system is designed for packaging all solid waste in standard-size 208 l stainless steel drums. Spent resins, evaporator bottoms and chemical drain tank effluents are encapsulated in the drums, while solid compressible waste is compressed directly in the drums. Incompressible waste is packed in the drums without further processing.
To reduce the volume of solid radioactive waste to be stored, supercompaction campaigns have been carried out. In 2006, the Krško NPP obtained a license and started to compress LILW with their own on-site supercompactor. Tube-type containers are used as preferred final package and as a drum overpack in the plant radioactive waste storage facility. The Krško NPP has started using an external service for the incineration of combustible waste.
Central Interim Storage for Radioactive Waste in Brinje is a near-surface concrete building with the roof covered with a soil layer. The building is subdivided by concrete walls into nine storage sections and an entrance area. The ground plan of the facility is 10.6 m x 25.7 m with a height of 3.6 m. The useful capacity of the storage is about 300 m3, and the remaining small area is intended for workers, for loading and unloading the waste and for internal transport. The facility is equipped with a ventilation system for reducing radon concentration and air contamination in the storage facility. The water and sewage collecting system is designed as a closed system to retain all liquids from the storage facility in the sump.
Spent Fuel storage: Spent fuel is stored in the spent fuel pool, inside the Fuel Handling Building of the Krško NPP. In 2003, a project of increasing the storing capacity of the spent fuel pool (reracking) was completed. After the reracking, 1694 storage locations are available for spent fuel. The storage capacity is sufficient for the planned lifetime operation until the year 2023. By the end of 2009, 928 locations were occupied.
Disposal Facilities: Currently in Slovenia there are no operational disposal facilities.
Reprocessing Facilities: Currently in Slovenia there are no reprocessing facilities.
In the Republic of Slovenia there is no nuclear facility in the process of decommissioning, excluding the remediation of the Žirovski vrh Uranium Mine.
Due to the growing need for a final disposal of LILW, the final solution for the short-lived LILW is the key issue of radioactive waste management in the Republic of Slovenia. The ARAO was in last few years intensely involved in the site selection process for a LILW repository.
The ARAO decided on the mixed mode site selection process. It is in practice a combination of technical screening and volunteer siting. It is flexible, transparent and it guarantees high public involvement. In 2009 National Spatial Plan was adopted by the government of RS and confirmed Vrbina (near NPP Krško) as the repository location. On the location Vrbina in Krško municipality, three repository variants have been considered in the design bases: surface repository, silos repository and tunnel type repository.
Based on evaluation, the ARAO proposed construction of the silo type of LILW repository. The LILW repository should be in operation in 2018 or other possible period.