1. Introduction

UJV Rez, a. s. (formerly the Nuclear Research Institute Rez, Czech Republic) has, for more than six decades, constituted the Czech Republic’s most important research and engineering organisation in terms of the support of the peaceful use of nuclear energy and ionising radiation. From the beginning, research concerned with radiochemistry and radioactive waste (RAW) management issues have made up an integral part of the company’s support activities.

1.1 Brief history

The Nuclear Physics Institute was established in 1955. This was an era that had yet to witness the deployment of satellites and space exploration and, for strategic reasons, a location in the deep valley of the Vltava River was chosen around 14 km upstream of the Prague for the construction of the facility (see Fig. 1). Today, it is hard to believe that within two years a VVR-S nuclear research reactor with a thermal output of 2 MW was designed, constructed and, in 1957, commissioned. The reactor was completely rebuilt in 1987-1989 and transformed into the LVR-15 research reactor with a thermal output of 10 MW that is still in use today (Fig. 2). The reactor is used for the research of materials, corrosion testing, the testing of the chemical regimes of power reactors, irradiation services, neutron activation analysis and the production of semiconductors. One of the facility’s most important activities in recent years concerns the production of radiopharmaceuticals and the irradiation of uranium targets to produce ⁹⁹Mo/⁹⁹Tc diagnostic radionuclide generator.

Fig. 1

View of the UJV Rez buildings in the Vltava river valley.

Fig. 2

The LVR-15 nuclear research reactor, Research Centre Rez (CVR).

A second experimental reactor, of the heavy-water TR-0 type with zero output, was commissioned in 1972 and, following reconstruction in 1982-1983, was converted to the light-water LR-0 type with a maximum thermal output of 5 kW. This reactor is used for the modelling of neutron fields and the testing of power reactor fuel and fuel batches.

Under the name Nuclear Research Institute Rez, UJV became known in 1970 when it focused on applied research and engineering support of the Czechoslovak nuclear programme.

In 1992, the Institute was transformed into the legal status of the Nuclear Research Institute Rez joint stock company (a. s.), the shareholders of which are nuclear operators ČEZ, a. s. and Slovenské elektrárne (SE, a. s.), nuclear manufacturer Skoda JS, a. s., and the municipality of Husinec. In 2012, the name of the company was changed to “UJV Rez, a. s.” (i.e. the abbreviated form of the previous name).

Two of the most significant events in the recent history of UJV Rez consisted of the acquisition in 2002 of ENERGOPROJEKT PRAHA a. s., the main designer of all the thermal and nuclear power plants constructed in the former Czechoslovakia and, in the period 2011–2017, the construction of the “Sustainable Energy” (SUSEN, see e.g. Fig. 3 and 4) infrastructure of the “Research and Development for Innovation” operational programme of the European Commission and the Ministry of Education of the Czech Republic at UJV Rez’s subsidiary company Research Centre Rez, s.r.o. (CVR) .

Fig. 3

The SUSEN infrastructure project–hot chamber at the CVR.

Fig. 4

The SUSEN infrastructure project-LOCA experimental setup at the CVR.

1.2 UJV Rez today

UJV Rez has a stable and consistent history. The company has more than 750 employees, over 60% of whom are engaged in research and engineering professions. The average employee age stood at 44.3-year-old and more than 60% of the company’s workforce had received a university education.

While most of the business activities of UJV Rez are conducted in the Czech Republic, the company continues to expand its operations in Slovakia, other EU and Eastern European countries and Asia. Involvement in foreign projects currently represents almost a quarter of the company’s annual turnover.

The UJV Rez and its subsidiary company Research Centre Rez, s.r.o. (CVR) boast an extensive research and technical infrastructure including nuclear research reactors, a cyclotron, hot and semi-hot chambers, gamma irradiators, experimental loops, structural material diagnostics laboratories, four accredited test laboratories for the determination of mechanical and other material properties, radiation chemistry and radiochemical analytics, three positron emission tomography (PET) medical diagnostic centres, laboratories for the research of processes underway and conditions within deep geological repositories, the Radioactive Waste (RAW) Management Centre, etc.

UJV Rez also utilises the latest available software tools for the 3D-database design as well as for modelling purposes and the determination of complex calculations (concerning, for example, thermomechanical, thermohydraulic and strength processes, rapid process dynamics, the design and optimisation of nuclear fuel batches, deterministic and probabilistic safety analysis, shielding design and related calculations, the dissemination of radionuclides in the environment, etc.).

UJV Rez is closely involved in international cooperation both through its membership of a number of major organisations (e.g. SNETP and NUGENIA), on the basis of bilateral or multilateral agreements (e.g. CEA, GRS, EPRI, SSTC NRS, US-DOE) and through its participation in various international projects (e.g. IAEA, OECD-NEA, EURATOM, Horizon 2020). Through international cooperation and research as well as commercial projects UJV Rez currently enjoys links with 33 countries worldwide.

1.3 UJV Rez products and services

Currently, UJV Rez provides engineering and research services in the following areas:

1.4 Research and development

As an important institution in terms of both domestic and European research, UJV Rez focuses on projects commissioned by operators and producers of equipment used in the energy sector and nuclear and conventional power plants as well as projects concerned with the processing and disposal of radioactive waste and diagnostic radiopharmaceuticals for positron emission tomography (PET) use. UJV Rez is today involved in a total of fifty-six grant programmes and projects.

1.4.1 International projects

UJV Rez is the Czech Republic’s most important participant organisation in EU-commissioned nuclear fission projects (EURATOM) and, in 2017, the company enjoyed active participation in three projects conducted under the EU’s 7th Framework Programme, i.e. Severe Accident Facilities for European Safety Targets (SAFEST), CArbon- 14 Source Term (CAST) and Preparation for the ESNII programme of the Horizon 2020 programme (ESNII plus).

As part of the Horizon 2020 programme, UJV Rez participated in a bunch of individual projects since 2015. Research continued into cement materials and their function in engineered barriers (CEBAMA; [1], [2]), strategies for reactor melt-down retention in the case of a severe accident (IVMR; [3]) and the development of the heat removal of supercritical CO₂ (sCO₂ HeRo) as well as issues concerning the tools and methodology for the management of the ageing of cables in power plants (TaM Cables; [4], [5]) and the European Joint Radiation Protection Integration Programme (CONCERT). Moreover, UJV Rez is also actively involved in the Visegrad Initiative for Nuclear Cooperation (VINCO) and a range of other programmes.

In addition, UJV Rez also participated in IAEA and OECD/NEA projects focused on enhancing the safety of nuclear power plants employing VVER-type reactors.

1.4.2 Domestic projects

In 2017, UJV Rez was involved in thirty-seven projects and grant programmes supported by the Technology Agency of the Czech Republic (TACR), the Ministry of Industry and Trade and the Ministry of the Interior as well as a number of commercial projects.

2. Radioactive waste (RAW) management

Radiochemistry and issues surrounding radioactive waste management have formed an integral part of UJV Rez’s activities since its establishment as a research institute. Today, the company’s Radioactive Waste & Decommissioning division is responsible for both the business and technical issues involved in this area [6].

The original field of research upon which today’s division continues to build was radiochemistry. The foundations were laid in 1952, i.e. prior to the establishment of the institute that is today known as UJV Rez. It was the third most important field (in addition to nuclear physics and nuclear power) to be developed at the Rez facility. Naturally, the nature and content of the various related activities have changed over time with the advent of new technologies, the development of nuclear power and, above all, the construction and operation of nuclear power plants.

In accordance with the applicable legislation and authorisation, UJV Rez is currently the only company in the Czech Republic able to cover the complete chain of RAW management from its detection to its safe storage/disposal (except the nuclear power plant fuel cycle) [7].

The services offered by the RAW & Decommissioning division with respect to the management of RAW include:

UJV Rez also provides services concerning the decommissioning of workplaces with sources of ionising radiation and support for the decommissioning of nuclear facilities.

Since 2007, UJV Rez specialists have been providing engineering and maintenance services for the transport of spent nuclear fuel from research reactors in the international context.

2.1 Institutional RAW management

Currently, UJV Rez processes for safe disposal almost 95% of the so-called institutional RAW (solid and liquid) generated in the Czech Republic in the industry, medical and other sectors. However, it is perhaps only fair to add that around 60% of such waste is produced by UJV Rez itself (see Table 1).

Table 1

Volume of RAW accepted for processing and transferred for storage

Typical examples of institutional waste consist of old fire alarms (that contain ²⁴¹Am), diagnostic medicine waste contaminated with ⁹⁹Tc (solid, biological) and various iodine isotopes, i.e. ¹²³I, ¹³¹I, and ¹²⁵I (liquid), irradiators that employ the ³H radionuclide for the excitation of phosphorescence and various closed radionuclide sources that are used as sensors and detectors or as calibration standards, etc. UJV Rez processes waste for around 45 regular customers, i.e. RAW producers.

Waste generated by the UJV Group of companies originates mainly from the operation of its research reactors and consists of e.g. refrigerant cleaning materials, discarded waste following repairs and maintenance and contaminated protective equipment. Historical RAW created via the remediation of the ecological liabilities of the former nuclear research institute makes up a special waste group [6].

The acceptance of RAW from its producers and its processing and handover for storage or disposal is provided for by the RAW Management Centre, which is equipped with the technology that enables the fragmentation, decontamination, processing and treatment of the waste. For example, it has a two-stage evaporation station for the thickening of liquid RAW, a solid waste press, an ultrasonic decontamination vessel, high-pressure blasting chambers for fragmentation and abrasive blasting, cementation lines, etc. The Centre also has the full range of handling and transport equipment along with waste transport containers. The Centre was completely reconstructed in 2011–2014.

2.2 Seizure of orphan or abandoned sources

The division is also responsible for the detection of orphan and abandoned sources of ionising radiation (socalled seizures) based on long-term contracts with SURAO (waste management organisation) and operators of communal damps and scrap yards. The usual scenario for this service is the removal of the seizure and the tracing and identification of the source, the securing of the capture pending the decision to trace the originator (or not), its processing and handing over for storage/disposal. Around twenty such procedures are conducted annually. Typical captures include waste from medical facilities, usually originating from the patient, or discarded instruments in which ²²⁶Ra containing paint has been used for luminescence.

2.3 Development and engineering support in the field of RAW

UJV Rez also addresses minor projects, though no less important in terms of maintaining and expanding overall knowledge, and contracts for research and engineering services concerned with radioactive waste management issues. The company has a permanent contract for the testing of the “liquid waste-bitumen matrix” system in order to verify compliance with waste acceptance conditions prior to the processing of the radioactive concentrate batches at nuclear power plants, in connection with which the company’s frobit experimental line (completely modernised in 2017, see Fig. 5) serves to simulate the conditions of the processing facilities of both of the Czech Republic’s nuclear power plants [8].

Fig. 5

Frobit experimental facility, UJV Rez.

Further contracts include the laboratory optimisation of the formula for the solidification of liquid and semi-liquid RAW (sludges, ion exchangers and concentrates) based on geopolymers, cement or mixed geo-cement matrices. The optimisation process is conducted in cooperation with Chemcomex a. s. [9]. The Mochovce nuclear power plant waste matrix was optimised in 2011–2012, followed by that of the Dukovany nuclear power plant from 2013–2014 and that of the Paks NPP (Hungary) in 2016–2017. Together with Chemcomex a. s. and based on previous optimisation and licencing verification experience, two contracts were awarded to UJV Rez for the consolidation of ion exchangers and sludges in ALUSIL matrices at the Dukovany nuclear power plant [9].

Considering R&D, the most complex challenge addressed by the company in recent years consisted of the “R&D of the RAW technology and management system of new nuclear sources” project (Ministry of Industry and Trade project no. FR-TI3/245) that was addressed in 2011– 2015. The project included the development of a filling simulator for the Dukovany RAW repository, technology for the processing and treatment of RAW (the optimisation of existing matrices–the so-called pure bitumen matrix, and the development of new matrices–geo-cement and polysiloxane matrices), the design of a system for management very low-level waste (VLLW), the development of advanced decontamination methods and new methodologies for the characterisation of radioactive materials [10].

Two of the most important projects currently underway are the “Knowledge Base for the Decommissioning of Nuclear Energy Facilities” project (Ministry of Industry and Trade application no. CZ.01.1.02/0.0/0.0/15_019/ 0004507 in co-operation with the Technical University of Liberec; 2016–2020) and “A Recyclable Decontamination Medium for the Decommissioning of Nuclear Facilities” project (Ministry of Industry and Trade no. FV10023, in cooperation with the Czech Technical University-Faculty of Nuclear Sciences and Physical Engineering and Chemcomex a.s.; 2016–2020; [11]). The main objectives of the first project are the development of a sampling probe for the collection of primary circuit piping material for the analysis, and design of a technological procedure for the processing of sorption materials from the cleaning of decontamination media during the decontamination of the primary circuits of nuclear power plants. The main aim of the second project involves the development of an original (patentable) decontamination medium designed specifically for WWER (VVER) nuclear power plant primary circuit materials.

Engineering support also includes the provision of expert consultation services, examples of which include input for a background study for the updating of the Czech National SNF and RAW Management Concept (2011–2012 for SURAO) and cost analyses for the back-end of the fuel cycle for SE, a.s. (Slovakia) (2010, 2014–2015).

2.4 Decommissioning issues (remediation of radiological liabilities)

The decommissioning of nuclear facilities with ionising radiation sources makes up a special area in terms of radioactive waste management. The objective of the decommissioning process is to remove the facility or site from the scope of the Atomic Act.

The provided services include the drafting of the documentation required to launch the decommissioning process, the development and design of decontamination and fragmentation techniques and procedures, special manipulators and other equipment, the processing and treatment of primary and secondary origin RAW and radiation protection management. With respect to the international environment, UJV Rez specialises in the collection and characterisation of materials, radiochemical analysis and radiation monitoring.

The practical application of the decommissioning process is illustrated by the long-term ongoing Remediation of Ecological Liabilities incurred at UJV Rez prior to Privatisation project. Further examples are provided by the remediation of a needle production line containing ²²⁶Ra at the Richard repository (2004) and the remediation of nuclear medicine facilities. The Radioactive Waste and Decommissioning division has accumulated considerable experience of such work at UJV Rez itself through the dismantling of the reactor vessel (see Fig. 6) and other parts of the original VVR-S reactor (modernised in 1988–1990), the removal and treatment of liquid and various types of solid RAW from underground storage tanks, the remediation of a closed facility for working with alpha nuclides, and the just finished removal and processing of around 50 m³ of waste contaminated with ²³⁹Pu and ²⁴¹Am.

Fig. 6

Dismantling of the reactor vessel from the original VVR-S research reactor at Rez.

Moreover, specialists from UJV Rez gained valuable experience via the decontamination of metal parts (pipes, tanks, fittings, etc.) by means of abrasive blasting with iron pellets in a special blasting chamber. Official monitoring by the specialist company NUVIA a. s. suggests that around 95% of the resulting material can be released directly into the environment.

2.5 European and international context

It is important that the nuclear community takes efficient management of waste streams as a top priority. In addition, as more legacy waste sites are being cleaned and the nuclear power plants around Europe moves towards decommissioning, the volumes of radioactive wastes to process prior to permanent geological disposal is increasing with time.

The project “PREDIS: Pre-Disposal Management of Radioactive Waste” (see https://predis-h2020.eu/) develops and improves safer treatment and conditioning methodologies and processes for wastes, for which no adequate or industrially mature solutions are currently available. The project addresses innovation and top-edge technologies for better handling of LLW and ILW radioactive wastes, with a focus on treatment of metallic materials, liquid organic waste and solid organic waste which can result from nuclear power plant operation, decommissioning and other industrial processes. The project also addresses digitalization solutions for improved safety and efficiency in handling and assessing cemented- waste packages in extended interim surface storage. An example of this is digital twins and the use of artificial intelligence for big data mining from non-destructive evaluation methods. Through all of these pre-disposal treatment activities, waste acceptance criteria are a critical parameter for optimizing the safe and efficient handling and minimisation of wastes over the whole life cycle, from cradle to grave. For the first results see e.g. the publication [12].

PREDIS will produce tools guiding decision-making on the added value of the developed technologies and their impact on the design, safety, environmental impact and economics of pre-disposal waste management and future disposal. It is anticipated that the project results are close to implementation by the end user community, which is ensured through their active involvement with the partners and the co-funding structure of this EC project. The project’s Strategic Research Agenda will highlight needs for future technology development, investments and needs also from the perspectives of competence development and preservation of knowledge.

With 47 partners from 17 countries across Europe, including UJV in 4 work packages, the 4 year, 24 millioneuro project, which started 1 September 2020, should make great strides in the best practices and new technologies ready for global markets.

3. Conclusions

UJV Rez a. s. is a stable and reliable company that provides unique research, application and engineering services in the field of the support of the use of nuclear energy and ionising radiation sources. The company’s technical infrastructure, knowledge base and experience as well as the skills of its employees are unique in comparison to many much larger countries than the Czech Republic and, in certain areas, the level of knowledge and skills and the technical infrastructure are comparable to similar companies in superpower countries.

UJV Rez forms one of the fundamental pillars that provide the Czech Republic with both a significant degree of independence with respect to the safe use of nuclear energy and a guarantee of its further development as the core element of a balanced energy mix. This also applies to the field of radioactive waste management. Much of the experience gained by UJV Rez has been successfully transferred to foreign markets and international cooperation, including the latest EU project PREDIS as an example of top edge development in the field of LLW and ILW pre-disposal management.

For information of EU project PREDIS, see https://predis- h2020.eu/. PREDIS project has received funding from the Euratom research and training programme 2014–2018 under grant agreement No. 945098.