Scientific Divisions / Nuclear Engineering Laboratory (14)
Nuclear Engineering Laboratory (14)
Prof. habil. dr. Povilas Poškas
Breslaujos 3, LT-44403 Kaunas
Phone: +370 (37) 40 18 91
Fax: +370 (37) 35 12 71
Main research areas of the Laboratory:
research of heat and mass transport in the equipment of biofuel-fired objects; reduction of emission along with flue gases resulting from biofuel combustion using electrostatic precipitators;
forced and mixed convection, turbulent and transition flow regimes, one and two-phase flows, influence of channel geometry, variable physical properties, roughness, effect of transient conditions and centrifugal forces;
numerical modeling of heat transfer and transport processes in various channels and geological structures;
safety of spent nuclear fuel (SNF) management: modeling of fuel characteristics, safety and environmental impact assessment of storage and disposal facilities, normative and legislative base;
safety of radioactive waste management: safety and environmental impact assessment of treatment technologies and storage and disposal facilities, normative and legislative base;
evaluation of different factors related to decommissioning of nuclear power plants: planning and cost of decommissioning and dismantling; radiological characterization of the area, buildings, systems and equipment; safety and environmental impact assessment of individual facilities; normative and legislative base;
assessment of fire hazard at nuclear power plants and other important facilities;
research related to construction of new nuclear power plant in Lithuania.
Researchers of Nuclear Engineering Laboratory together with other laboratories of the Institute coordinate and implement two long-term scientific research and experimental development programs, which were approved by the Ministry of Education and Science of the Republic of Lithuania in early 2012:
Investigation of single-phase and two-phase flow dynamics, heat and mass transfer processes (2012–2016). The objective of the program is to develop research methods and perform investigations of single-phase and two-phase flow structure, heat and mass transfer regularities in dealing with the efficiency of new heat energy production from biofuel schemes, energy and mass flow measurement and heat and mass transfer intensification tasks under transient flow conditions, flow in transition region, impact of physical features and buoyancy forces and vapor condensation processes.
Investigation of nuclear power plant decommissioning and nuclear waste and spent fuel management processes and radiation impact analysis (2012–2016). The objective of the program is by applying numerical and experimental research methods and taking into account the peculiarities of Ignalina NPP decommissioning processes to analyze and estimate radiation impact on humans and environment during management, storage and disposal of SNF and radioactive waste.
Research of thermal processes in energy equipment components
Biofuel is rather widely used in many countries for heat and electric power production. It (wood, straw, grain, etc.) is considered a renewable energy source, causing the least environmental impact; this is why its consumption increases not only in the newly built, but also in the reconstructed boiler houses in Lithuania. However, one of the major drawbacks comparing biofuel combustion to gas or liquid fuel combustion is a quite large release of solid particles into the environment. With the growing number of devices burning biofuel, the emission of solid particles increases. Due to the harmful impact to the human health, the amount of solid particles in the flue gas of the combustion devices is limited, i.e., various filters that capture these solid particles are installed. The efficiency of cyclone and other mechanical devices capturing solid particles usually used in Lithuania is too small for capturing small particles streaming with the flue gas; by means of electrostatic precipitators, a very high efficiency of gas (flue gas) cleaning can be achieved. While burning fuel, different sizes of solid particles are emitted, and the composition of flue gas changes; due to this, the efficiency of electrostatic precipitators changes. An exhaustive analysis of these factors enables solving relevant issues related to upgrading technologies in the Lithuanian energy sector.
Researchers of the Laboratory in the frame of the project Research of local fuel thermal decomposition processes by developing efficient and ecological technologies (2012–2014)
, financed by national research program “Future Energy
” of the Research Council of Lithuania together with other laboratories of the Institute conducted investigations on cleaning flue gas. During the project, an experimental device was manufactured, and preliminary research was performed. A prototype of the electrostatic precipitator manufactured at the Laboratory was used for the research. Relative concentration of the particles was determined taking into consideration the voltage supplied to the electrostatic precipitator when discharge electrode is positive or negative. The conducted research enabled to determine the efficiency of the electrostatic precipitator.
Researchers of the Laboratory together with other laboratories of the Institute also implement another project Development of Innovative Thermal Decomposition Technology and its Application for Utilization of Sewage Sludge (2013–2015) based onthe measure of the third priority Strengthening capacities of researchers Promotion of High International Level Scientific Research of the program for the Development of the action of human resources approved by the Ministry of Education and Science. Sewage sludge is retrieved as waste in Lithuanian wastewater treatment enterprises. While the infrastructure of wastewater collection and treatment expands, the amount of sludge generated during wastewater treatment increases proportionally. Huge amounts of sludge stored in sludge sites begin to evoke hazard for the environment and contradict to sustainable development principles. Therefore, the most effective methods are searched to treat wastewater sludge. One of the most innovative methods for utilization of waste sludge is its gasification. Applying this technology, a valuable product is released from sludge during thermal decomposition – flammable gas, which may be used in heat and electricity production. Gasification enables to reduce not only the volume of the generated sludge and obtain additional energy, but also to reduce the environmental pollution. During the project, it is planned to develop a pilot prototype of gasification process-technology of up to 100 kW, which will be highly promoted to attract possible Lithuanian and/or foreign investors interested in commercial size operating technology, applicable for utilization of sludge generated in small towns of Lithuania.
In 2014, during implementation of this project, an experimental research of flue gas purification was performed. The research results demonstrated that when burning biofuel (wood pellets), the most part of solid particles with diameters ranging from ~0.4 µm to ~15 µm dominate in untreated flue gases. The largest amount of particles is with the diameter up to ~4 µm. Solid particles from flue gases are cleaned using electrostatic precipitator. When the voltage applied to the precipitator was 12 kV, the obtained results showed that the decrease of concentration of solid particles was
~99 %. During gasification of biofuel pellets, concentration of solid particles is greater; moreover, the combustion process and its control process are more complicated; this is why, the decrease of particle concentration using electrostatic precipitator was ~85 %.
The Laboratory also carries out investigations on heat transfer and hydrodynamics in energy equipment for different purposes (in elements of nuclear reactors, various heat exchangers, etc.). In both laminar and turbulent flow cases, surface roughness, centrifugal and buoyancy forces (mixed convection) can impact heat transfer in many energy installations, which under certain conditions can become a reason for an accident in different installations. Therefore, in order to analyze such problems in depth, the laboratory performs experimental mixed convection investigations in various channels. In parallel, numerical investigation is also performed using ANSYS CFD code (ANSYS, USA), which is widely applied in the world for modeling fluid movement and heat transfer in complex two and three-dimensional systems. Taking into consideration the flow mode, various models of laminar, transitional and turbulent transfer are used. Additionally, such research was initiated in geological structures while analyzing the possibilities of Ignalina NPP spent nuclear fuel disposal.
In 2012, the Laboratory participating in activity of the project Santaka Valley by the open access scientific research and experimental development (R&D) center obtained LDA and PIV equipment, designed to investigate flow structure in gas and liquids in wide range of velocity variation. This equipment can measure flow velocities, pulsations, and vortex rotational frequencies, and it can visualize them, etc. Furthermore, the Laboratory obtained liquid crystal thermography equipment enabling to measure temperature of various objects and variation of temperature of an individual visual part of the analyzed object in a remote non-invasive way.
In 2013, according to the European Union structural fund support measure Innovation Vouchers LT administered by the Agency for Science, Innovation and Technology, researchers of the Laboratory improved the efficiency of JSC Wilara beebread dryer. After experimental research and numeric modeling of air flow distribution, non-uniformity of drying airflow was resolved.
In 2014, fundamental experimental and numerical research of mixed convection heat transfer and flow structure in flat channel in turbulent and transitional flow areas applying ANSYS CFD (USA) software continued.
Research on safety of spent nuclear fuel management
After the decision to use dry storage facility for spent nuclear fuel (SNF) at Ignalina NPP in CASTOR and CONSTOR type casks, back in 1997, researchers of the Laboratory started performing studies related to the safety assessment of SNF management, storage and disposal. The Laboratory carried out criticality assessments for casks with SNF under normal operational and accident conditions, variation of radionuclides activity during the storage period, radiation doses on the cask surface and at the specific distance from it as well as temperatures.
Implementing the research on SNF disposal in Lithuania, the Laboratory experts with the assistance of Swedish experts proposed the concepts of deep geological repository in clay and in crystalline rocks for SNF and long-lived intermediate level waste in Lithuania. The concepts on disposal are constantly defined more precisely and optimized taking into account international experience and physical, chemical, thermal and mechanical properties of a specific repository site. While analyzing the possibilities of SNF disposal in Lithuania, the cost assessment of geological repository installation was carried out, and generic repository safety assessment was initiated.
The Laboratory together with consortium GNS – NUKEM Technologies GmbH (Germany) implements an extensive project Design and Installation of the Interim Storage Facility for RBMK Spent Nuclear Fuel Assemblies from Ignalina NPP Units 1 and 2 (2005–2015). This project comprises the analysis of all activities related to the design, construction, installation, commissioning, operation and decommissioning of the new SNF storage facility and the performance of all necessary works related to SNF removal, packaging, sealing and transfer as well as operation of the appropriate equipment for implementation of chosen design concept. It is planned to store approximately 200 new type CONSTOR casks with intact and damaged SNF in the new storage facility. Researchers of the Laboratory prepare Environmental Impact Assessment and Safety Analysis Reports of this SNF storage facility (operational time no less than 50 years) and offer support in licensing the storage facility. In 2007, Environmental Impact Assessment Report was approved by the Ministry of Environment; in 2009, Preliminary Safety Analysis Report (PSAR) was prepared and agreed upon, and the license for construction of the new SNF storage facility was issued by VATESI. In 2010–2011, PSAR Addendum, which presents the evaluation of safety aspects of damaged RBMK-1500 nuclear fuel assemblies management and storage, was prepared. In 2014, taking into consideration certain changes to the technical design made during construction works of SNF storage facility, the Updated Safety Analysis Report was prepared, and according to VATESI comments, PSAR Addendum, related to management of damaged SNF assemblies, was revised.
In 2014, scientific study financed by the budget subsidies Integrated research on generation of radioactive contamination, its impact and migration upon termination of RBMK-1500 reactor operation and storage and disposal of radioactive waste (2013–2015) continued. In this study, the researchers of the laboratory by means of numerical methods evaluated the way the nuclide content of the RBMK spent nuclear fuel, radiation characteristics, dissipation of residual heat in the long-term storage change, and the way these parameters depend on the load of the reactor, density of coolant and cross-section libraries used in modeling. This assessment is important for estimating the impact of ionizing radiation on the environment and ensuring safe operation of SNF storage facilities. Fuel with different U-235 enrichments was used during Ignalina NPP operation; however, as the assessments of gamma and neutron emission spectra reveal, the initial fuel enrichment has insignificant influence on the radiation characteristics.
Moreover, this scientific research financed by the budget subsidies continued the study of radionuclides, gas and heat migration in engineering and natural barriers of geological repositories. Taking into consideration the geological conditions of the Ignalina NPP region, a conceptual and numerical models for groundwater flow and radionuclide transport in geological repository implementedin crystalline rocks were developed. After the assessment of the influence of natural barrier properties on the radionuclide I-129 migration, it was determined that the uncertainty of hydraulic conductivity had a more significant impact on radionuclide concentration than uncertainty of diffusion coefficient and porosity.
After the assessment of gas migration in the module of a geological repository, situated in clay formation, it was determined that engineering interfaces, tunnel filling material and excavation disturbed zone (EDZ) are the main migration and accumulation materials of gaseous hydrogen generated due to corrosion of steel SNF containers. The sensitivity analysis that evaluated the influence of characteristics of engineering interfaces on gas migration showed that the maximum gas pressure in the module (in cases of reference and local sensitivity analysis) did not exceed the lithostatic (geological environment) pressure at a depth of 500 meters, thus it is not sufficient to disturb mechanical stability and functionality of the system of engineering barriers.
In 2014, the researcher of the Laboratory participated in a workshop in Sweden, where scientists from countries (France, Finland, Sweden, and Switzerland) with more advanced programmes in the field of geological disposal presented the concepts of their repositories, shared practical experience and challenges, arising during construction of underground tunnels of geological repositories for disposal of SNF. The seminar participants also visited Swedish SNF interim storage facility, copper SNF container plant in Oskarshamn, and Äspö underground research laboratory, situated in crystalline basement at the depth of 450 m under the Baltic Sea.
In 2014, researchers of the Laboratory also participated in IAEA Technical meeting on Understanding and Establishing an Adequate Engagement Process with the Relevant Stakeholders in Pursuing a Geological Disposal Programme in Vienna (Austria) called to establish cooperation ties with the interested parties.
Researchers of the Laboratory use software code SCALE (USA) for modeling fuel characteristics (assessment of criticality), for assessment of nuclide content of spent nuclear fuel and evolution. PETRASIM (USA) and GOLDSIM (USA) software tools are used for assessment of safety of radioactive waste repositories. Using this software, modeling of radionuclide/gas transfer (one-phase/two-phase flow) in porous and fractured medium is performed. Software codes COMSOL (USA) and COMPASS (GRC, the United Kingdom) are used for evaluation of influence of thermal-hydro-mechanical and chemical processes on groundwater migration in geotechnical environments.
Safety research of radioactive waste management
Since 1994, the Laboratory has been actively involved in the analysis of the radioactive waste management problems at Ignalina NPP. Laboratory experts together with the experts from SKB International (Sweden) carried out several projects, which assessed the existing Ignalina NNP waste storage facilities and the possibilities to transform them into repositories.
In 2002, the Laboratory together with Framatome ANP GmbH (Germany) participated in performing the environmental impact and safety assessments for Ignalina NPP cement solidification facility and an interim solidified radioactive waste storage facility.
In 2004–2005, together with French companies Thales Engineering and Consulting, ANDRA and the Institute of Physics, PHARE project Safety Assessment and Upgrading of Maišiagala Repository in Lithuania was implemented. The Laboratory specialists participated in preparing Safety Analysis Report, developed the database containing information on radioactive waste, which is stored in the Maišiagala storage facility, and performed a comprehensive nuclide composition analysis.
In 2002–2005, a great deal of attention was given to the siting of a new near-surface repository for radioactive waste in Lithuania, scientific research related to the radionuclide migration from radioactive waste repositories and its impact on safety. With the assistance of Swedish experts, researchers of the Laboratory determined the criteria for choosing a near-surface repository site, improved the reference design of a near-surface repository and prepared the implementation program. The impact of heterogeneous (uneven) waste activity distribution on radionuclide migration from model near-surface repository was investigated.
In 2006–2009, researchers of the Laboratory implemented the project Reconstruction of Ignalina NPP Bitumen Radioactive Waste Storage Facility (Building 158) into Repository. A long-term safety assessment of the planned repository was prepared; it was based on the possible engineering solutions of storage facility reconstruction into repository, components of disposal system. To be more precise, radioactive waste, storage facility and surface engineering barriers planned to be installed over storage facilities and site characteristics were taken into consideration.
In 2008–2013, the Laboratory, as a partner of Lithuanian consortium (JSC Specialus montažas-NTP, LEI, SC Pramprojektas, JSC Vilstata) implemented the project Installation of Very Low Level Radioactive Waste Repository (Landfill). Landfill repository is intended for disposal of very low-level radioactive waste generated during Ignalina NPP operation and decommissioning. The entire Landfill facility will be comprised of three repository modules and a buffer storage, where waste will be stored until its disposal. In 2009–2013, researchers of the Laboratory prepared Environmental Impact Assessment Report for the planned economic activity, two preliminary safety analysis reports (for buffer storage and waste disposal units), two general data sets, final safety analysis report and waste package description of the radioactive waste packages intended for disposal.
In 2014, the Laboratory together with NUKEM Technologies GmbH (Germany) continued implementing the project New Ignalina NPP Solid Waste Management and Storage Facility (2006–2015). This facility is intended for solid radioactive waste retrieval, sorting, transportation, treatment (following envisaged technologies), packaging, characterization and storage. The entire facility will be comprised of several facilities located at two sites: the solid waste retrieval facility at the existing Ignalina NPP solid waste storage buildings, and new facility located nearby INPP for solid waste treatment and storage. In 2008, Environmental Impact Assessment Report was agreed upon and approved at the Ministry of Environment. Also, two Preliminary Safety Analysis Reports (PSARs) were prepared: New Solid Waste Treatment and Storage Facility at Ignalina NPP and New Solid Waste Retrieval Facility at Ignalina NPP. The first PSAR was approved in 2009, and VATESI issued a license for the construction of the storage facility. In 2009, two more PSARs New Solid Waste Retrieval Facility for Retrieval Unit 1 and Retrieval Units 2–3 at Ignalina NPP were prepared. In 2010, both PSARs were submitted to the institutions for review. The first PSAR was updated following the recommendations by the institutions, and at the end of 2010 was approved by VATESI, while in the middle of 2011, the permission to build the facility was received. In 2011–2014, the second PSAR was updated considering the recommendations of the institutions. In the late 2014, VATESI approved documents justifying safety for Waste Retrieval Units 2-3. An updated PSAR is currently prepared for release. In 2017–2018, the Final Safety Analysis Report will be prepared.
In 2014, the Laboratory together with partners from French companies AREVA TA and ANDRA and Lithuanian partners JSC Specialus montažas-NTP and Pramprojektas continued the project Low and Intermediate-Level Short-Lived Radioactive Waste Near-Surface Repository (Design) (2009–2015). The repository is intended for disposal of low and intermediate-level short-lived radioactive waste generated during Ignalina NPP operation and decommissioning. In 2010–2011, the specialists of the Laboratory made a considerable contribution to the preparation of Design Options Report, Waste Inventory Report and Site Revalidation Report, which were submitted to the Contractor and approved. In 2012, Basic Engineering Design Report for Low and intermediate-level short-lived radioactive waste near-surface repository was prepared and submitted. For this report, the experts of the Laboratory prepared four chapters: waste inventory, long-term safety assessment, waste acceptance criteria and waste package specification as well as environment monitoring and surveillance overview.
In 2014, researchers of the Laboratory finished the preparation of preliminary safety analysis report and submitted it to the Customer. The conducted safety assessment covers the operational period and long-term safety (period after closure of the repository). In 2014, repository environment monitoring program was prepared and submitted to the Customer.
In 2014, researchers of the Laboratory began the Strategic Environmental Impact Assessment (SEIA) of the project of Development Programme for Radioactive Waste Management that is prepared by Radioactive Waste Management Agency (RATA). SEIA report establishes, characterizes and evaluates the possible significant consequences of the implementation of Development Programme for the environment, including spent nuclear fuel and radioactive waste management. In 2015, a public introduction to the Development Programme for Radioactive Waste Management and SEIA Report will take place, the society and responsible state institutions will be consulted.
In 2014, researchers of the Laboratory continued the scientific research financed by the budget subsides, in which they performed investigations of impact of waste zone inhomogeneity evaluating radionuclide migration from the near surface radioactive waste repository. For this purpose, three models of waste zones with various complexities were created: homogenous, layered and three-dimensional.
The results of the investigation revealed that assessing migration of short-lived radionuclides, the homogenous model is very conservative (an increased impact of radionuclides is obtained). Therefore, in order to optimize the repository design and still preserve the necessary safety level, more complex models of waste zone should be used.
Researchers of the Laboratory for modeling migration of radioactive and non-radioactive contaminants in the environment use software AMBER (Quintessa, the United Kingdom). For the analysis of contamination of environment due to constant or one-time release of radionuclides into the atmosphere, surface water and soil or their initial contamination and calculation of human received doses software code GENII (PNNL, USA) is used. Software codes GWSCREEN (INEEL, USA) and DUST (BNL, USA) are used to assess the leaching of radionuclides from the surface type radioactive waste storage. For modeling water balance, forecasting underground water level, evaluating scenarios of climatic change software GARDENIA (BRGM, France) is used. Geochemical research is being carried out using software EQ3/6 (Lawrence Livermore National Laboratory, USA) that enables to compile models for the assessment of chemical processes taking place in the analyzed water/solid phase systems, designed for modeling chemical changes of contaminants (radionuclides), solubility and sorption in water/solid phase systems.
Evaluation of different factors related to decommissioning of nuclear power plants
Back in 1998, researchers of the Laboratory initiated research related to Ignalina NPP decommissioning. Our experts participated in PHARE project preparing Preliminary Ignalina NPP Decommissioning Plan as well as Final Ignalina NPP Decommissioning Plan. In 2004, researchers of the Laboratory in accordance with the order of the Ministry of Economy of the Republic of Lithuania prepared projects for Ignalina NPP decommissioning program and its implementation measures plan for 2005–2009. In 2005–2008, together with the Institute of Physics the project Development of Radiological Characterization Programme for Equipment and Installations at Ignalina NPP was implemented.
Since 2007, Nuclear Engineering Laboratory has actively participated in Ignalina NPP dismantling projects. Lithuanian Energy Institute, as a partner of consortium Babcock (former VT Nuclear Services Ltd) (the United Kingdom) – LEI – NUKEM Technologies GmbH (Germany), implemented the project Ignalina NPP Building 117/1 Equipment Decontamination and Dismantling (2007–2010). With the same partners, they implemented the project Ignalina NPP Building V1 Equipment Decontamination and Dismantling (2009–2012).
In 2009, specialists of the Laboratory prepared and coordinated with the institutions the Environmental Impact Assessment Report; in 2010, General data collection on waste disposal was prepared. Specialists of the Laboratory participated during preparation of the Basic design, which in 2010 was coordinated and transferred to the Customer, and Detail design and Safety justification,which were coordinated with the institutions. Researchers of the Laboratory analyzed the equipment in Building 117/1, the amount of accumulated waste and their characteristics and carried out the assessment of the planned economic dismantling and decontamination activity. On December 1, 2010, employees of Ignalina NPP, based on the prepared documentation, began dismantling and decontamination of the equipment in Building 117/1, which were completed in October 2011.
Researchers of LEI Nuclear Engineering Laboratory also as partners of consortium Babcock (the United Kingdom) – LEI – NUKEM Technologies GmbH (Germany), implemented the project Ignalina NPP Building V1 Equipment Decontamination and Dismantling (2009–2012). In 2010, specialists of the Laboratory finished preparation of General data collection on waste disposal. In 2011, specialists of the Laboratory prepared and coordinated with the Ministry of Environment Environmental Impact Assessment Report. In 2012, Basic design and Safety justification were coordinated, and Detail design was submitted to the Customer. In 2012, employees of Ignalina NPP, based on the prepared documentation, began dismantling and decontamination works of the equipment in Building V1. At the end of 2013, dismantling stage D1 was completed, during which about 640 tons of equipment were dismantled. During 2023–2028, it is planned to implement dismantling stage D2 of Building V1.
In 2014, Laboratory of Nuclear Engineering, as a partner of international consortium (JSC Specialus montažas-NTP – FTMC – LEI – ATP (Bulgaria) – INRNE (Bulgaria) – VNIIAES (Russia) continued the project The Evaluation of the Material Backlog and Radiological Inventory of Kozloduy NPP Units 1 to 4 (2012–2015). The objective of the project is to carry out a detailed evaluation of the radiological status of the equipment, structures, compartments and the radioactive waste and assess the total radiological inventory and material backlog of the Kozloduy (Bulgaria) NPP Units 1–4 (WWER). In 2014, main tasks performed by the experts of the Laboratory included neutron activation and dose rates verification calculations for the structures of Unit 3 WWER-440 reactor.
In 2014, researchers of the Laboratory further improved their developed software code DECRAD. The main objective of application of software code DECRAD is to assess the cost and expenses of dismantling and decontamination works, estimate labor requirements, calculate radiation doses received by personnel, plan the quantity and activity of the accumulated radioactive waste, assess the number of packages and other parameters related to decommissioning of nuclear facilities. This software code can be applied for planning and analysis of decommissioning works for various nuclear facilities and individual buildings or units. Also, using DECRAD software a Multi-criteria Decision Analysis may be performed. The AHP (Analytic Hierarchy Process) method used in parallel with the DECRAD software is one of the most relevant methods for selecting the alternatives for dismantling nuclear facilities.
In 2014, DECRAD-ACT program (developed in 2013) was further improved; it expands the functionality of DECRAD and is designed for collecting and processing data on activated nuclear reactor components. This program is used in the mentioned-above Kozloduy NPP project.
For the analysis of uncertainty and sensitivity of radioactive contamination results, caused by uncertainty of the input parameters, researchers of the Laboratory developed an extension model of LLWA-Decom program on .NET platform and an interface with MATLAB program. This system is used for the analysis of radiological contamination of Ignalina NPP systems.
In 2014, researchers of the Laboratory continued the research work financed by the budget subsidies, the objective of which is by applying modern numerical research methods to assess and specify characteristics of radioactive waste, resulting from decommissioning and dismantling of RBMK reactors, determining the selection of waste treatment methods, engineering structures of handling and storage facilities and repositories, and to perform an integrated analysis of radioactive exposure of personnel and population due to ionizing radiation caused by radioactive waste and spent nuclear fuel.
In 2014, researchers of the Laboratory carried on the IAEA coordinated project Data Analysis and Collection for Costing of Research Reactor Decommissioning (DACCORD) (2012–2015). The objective of this project is to present means, recommendations and assistance in preparation of the preliminary assessment of expenses for countries that are implementing or plan to implement dismantling of small nuclear facilities or experimental nuclear reactors.
Researchers of the Laboratory improved their competence in this field by participating at the international applied research workshop organized by Ignalina NPP on the issues of decommissioning of uranium-graphite nuclear reactors (July 15–16, 2014, Visaginas), training course Assessment of occupational exposure due to intakes of radionuclides organized by IAEA (June 2–6, 2014, Athens, Greece), and regional workshop Experiences in radiological characterization and activation calculations for decommissioning organized by IAEA (December 15–19, 2014, Visaginas (Ignalina NPP)).
Since 2002, the Laboratory carries out fire safety assessment at nuclear power plants and other important facilities. Researchers of the Laboratory consulted by Swedish experts assessed fire safety of reactor Unit 1 and Unit 2. Moreover, they assessed fire safety of some renewed Ignalina NPP rooms with changed designation and newly designed Ignalina NPP SNF and radioactive waste storage facilities. An external fire impact on the new INPP Solid Waste Storage and Treatment Facility was assessed, and the analysis of fire hazard in the most dangerous areas in case of an internal fire in the facility was performed. In 2009, the impact of fire during the implementation of dismantling and decontamination of Ignalina NPP Building 117/1 was evaluated as well as fire safety of newly designed buffer storage and disposal units of Landfill repository was assessed. In 2010, the impact of fire during the implementation of dismantling and decontamination of Ignalina Unit V1 was assessed. In 2012, based on Detail design documentation, the fire hazard impact in very low activity radioactive waste repository was estimated, and in 2014, during preparation of documents justifying safety of low and intermediate activity radioactive waste repository, fire hazard analysis of this facility was performed.
At the end of 2014, researchers of the Laboratory began implementing a research work Fire hazard analysis of bitumen radioactive waste storage facility (2014–2015), in which they will perform fire hazard analysis for Ignalina NPPbitumen radioactive waste storage facility.
For modeling neutron, photon and electron (radiation) transport, researchers of the Laboratory use software code MCNP-MCNPX (Los Alamos National Laboratory, USA). The assessment of scattered gamma radiation emanating from various nuclear facilities (e.g., Radioactive Waste Storage and Disposal Facility, etc.) is carried out by software MicroSkyshine. Personnel effective dose is assessed by software VISIPLAN (SCK-CEN, Belgium) and MICROSHIELD (GroveSoftware, USA). Modeling of dispersion of contaminants emitted by various contamination sources is performed by AERMOD VIEW (Lakes Environmental Software, USA) software. Fire modeling is performed by software code PYROSIM (USA).
Research related to the construction of a new nuclear power plant in Lithuania and international activity of the Laboratory
In 2007–2009, at the consortium, researchers of the Laboratory together with Pöyry Energy Oy (Finland) conducted research related to the construction of a new nuclear power plant in Lithuania. The Environmental Impact Assessment Program for New Nuclear Power Plant and New Nuclear Power Plant Environmental Impact Assessment Report were prepared. In the EIA Report, possible environmental impacts of the construction and operation of new NPP were assessed in cooperation with other Finish and Lithuanian institutions (Institute of Botany, Institute of Ecology and National Public Health Surveillance Laboratory). According to the EIA Report of 2009, positive conclusions of the competent authorities were made concerning the planed economic activity; therefore, following this EIA Report, the Ministry of Environment made a motivated decision on the construction possibilities of a new nuclear power plant in Lithuania.
In 2014, researcher of the Laboratory participated at the IAEA regional workshop Radiological Consequences Analysis for Nuclear Power Plants and Power Units that took place in Yerevan (Armenia), where issues related to the assessment of radiological consequences of beyond design basis and severe accidents were discussed. During the meeting, a presentation Radiological Consequence Analysis in EIA Report of Planned New NPP in Lithuania was given; the review of radiological impact of beyond design basis and severe accidents in Lithuania was presented.
Since 2008, researchers of the Laboratory actively participate in the European Union 7th Framework Program funded scientific research and coordination and support activity projects. The following projects have already been implemented: Treatment and Disposal of Irradiated Graphite and Other Carbonaceous Waste (CARBOWASTE) (2008–2013), Fate of Repository Gases (FORGE) (2009–2013), New MS Linking for an Advanced Cohesion in EURATOM Research (NEWLANCER) (2011–2013), Sustainable network of Independent Technical Expertise for radioactive waste disposal (SITEX) (2012–2013). In 2014, researchers of the Laboratory continued work in three EU 7th Framework Program funded projects.
CArbon-14 Source Term (CAST) (2013–2018). This project aims to develop understanding of the generation and release of C-14 from radioactive waste materials under conditions relevant to waste packaging and disposal to underground geological disposal facilities. The project will focus on releases from irradiated metals, ion-exchange resins and graphite. The project is implemented by 33 partners from 12 EU countries and 3 non-EU countries. In 2014, information about radiocarbon inventory in and its releases from the reactor RBMK-1500 irradiated graphite and about evaluations of radiocarbon in safety analyzes in Lithuania was collected and systematized. In October 2014, researcher of the Laboratory also participated in the general assembly meeting of the CAST project in Brussels (the Kingdom of Belgium).
Assessment of Regional Capabilities for New Reactors Development through an Integrated Approach (ARCADIA) (2013–2016). The objective of the project is to support and develop nuclear scientific research in new EU states related with the development of IV generation reactors, devoting the main attention to ALFRED (lead cooled reactor) demonstrator. The project is implemented by 26 partners from 14 EU states. Researchers of the Laboratory participate in this project together with the Laboratory of Nuclear Installation Safety.
Building a platform for enhanced societal research related to nuclear energy in Central and Eastern Europe (PLATENSO) (2013–2016). The objective of the project is to enhance the capabilities of research institutions in Central and Eastern European countries to take part in EU research with respect to governance, social and societal aspects linked to nuclear energy. The project is carried out by 19 partners from 12 EU states. In 2014, two PLATENSO partner meetings took place; one in Warsaw (Poland), and the other one in Barcelona (Spain), where project achievements were presented and future works were discussed.
Researchers of the Laboratory constantly participate in research projects and programs coordinated by IAEA. The following projects have already been completed: Improving Long Term Safety Assessment Methodologies for Near Surface Radioactive Waste Disposal Facilities (ISAM) (1998–2001), Application of Safety Assessment Methodology for Near-Surface Waste Disposal Facilities (ASAM) (2002–2005), Disposal Aspects of Low and Intermediate Level waste derived from decommissioning activities (2002–2006), The Use of Numerical Models in Support of Site Characterization and Performance Assessment Studies of Geological Repositories (2005–2010). In 2014, two projects were implemented:
Treatment of RBMK-1500 irradiated graphite in order to meet disposal requirements in Lithuania (2010–2014); this project is implemented within the framework of joint research project Treatment of irradiated graphite in order to meet waste acceptance criteria for disposal coordinated by IAEA. In 2014, all the foreseen works related to investigations of radiological properties of RBMK-1500 irradiated graphite in Lithuania were completed, and in 2015, IAEA plans to issue a general project report.
Investigation of RBMK-1500 Spent Nuclear Fuel and Storage Casks Performance during Very Long Term Storage. (2012–2016); this project is implemented within the framework of the project Demonstrating Performance of Spent Fuel and Related System Components during very Long Term Storage coordinated by IAEA. In November 2014, in Tokyo (Japan), a second meeting of project participants took place, where the results of research conducted in various countries were discussed, and the research of the features of RBMK-1500 spent nuclear fuel and storage containers in Lithuania was submitted. The participants visited Tokai nuclear research center Nuclear Development Corporation (NDC).
In 2014, the project Research of local fuel thermal decomposition processes by developing efficient and ecological technologies (2012–2014) financed by national research program of the Research Council of Lithuania Energy for the Future implemented with other laboratories of the Institutewas completed.
On June 30, 2014, a researcher of the Laboratory Darius Justinavičius defended a doctoral dissertation in the field of Technological Sciences, Energy and Thermal Engineering Investigation of gas migration in a geological repository and was conferred a doctoral degree.
Researchers of the Laboratory implemented 17 applied studies and earned almost a million litas. Moreover, they actively improved their qualification by participating in various training programs, coordinating meetings, delivered five papers at the international conferences (in Portugal, the United Kingdom, Czech Republic and in Lithuania) and three papers at the national conferences, published six articles in journals listed in Thomson-Reuters database Web of Science Core Collection.