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Scientific Divisions / Laboratory of Nuclear Installation Safety (17)

Laboratory of nuclear installation safety (17)

Laboratory Chief

Dr. Habil. Eugenijus Ušpuras

Breslaujos 3, LT-44403 Kaunas

Phone +370 (37) 40 19 26+370 (37) 40 19 26
Fax     +370 (37) 35 12 71
Eugenijus.Uspuras


Main research areas of the laboratory:
 
    safety assessment of nuclear power plants;
    safety analysis of thermonuclear fusion reactors;
    analysis of new generation nuclear power plants;
    analysis of thermal-hydraulic accident and transient processes;
    assessment of change of thermal-hydraulic parameters in NPP containments and other premises;
    simulation of transport of radionuclides and aerosols in premises;
    analysis of reactive accident processes of nuclear reactor and justification of modifications in reactor core;
    safety assessment of decommissioning and dismantling of nuclear installations;
    reliability estimation and control of energy systems;
    level 1 and level 2 probabilistic safety assessment of NPPs;
    strength analysis of structures, piping and components in complex technical systems;
    failure analysis and engineering assessment for complex technical systems;
    risk and hazard assessment of industrial objects;
    assessment of security of energy supply;
    modeling and reliability assessment of processes in energy supply networks;
    probabilistic modeling and analysis of unusual events;
    analysis of sensitivity and uncertainty of modeling results;
    fundamental research in thermal physics.
 
In 2014, the researchers of the Laboratory together with other national and foreign subjects were implementing 30 projects: 3 budget subsidy funded research works; 2 projects funded by the national research program Energy for the Future; 1 long-term institutional scientific research and experimental development program; 22 international projects (8 projects of the EU 7th FP); 2 projects ordered by Lithuanian economic subjects.
 
 
1. National research program Energy for the Future
 
In 2014, the researchers of the Laboratory continued two projects of the national research program Energy for the Future financed by the Research Council of Lithuania.
The aim of the project Reliability and risk study of Lithuanian energy systems (ATE-04/2012), implemented in 2012–2014 by the national research program Energy for the Future administered by Research Council of Lithuania, is to perform reliability and risk study for the Lithuanian energy systems based on the methodology developed during Project ATE-10/2010 implemented in 2010–2011.
 
The study covers the main parts of the energy system: electricity, district heating supply, and gas pipeline systems. A complex methodology, including probabilistic and deterministic methods, was applied for the assessment of reliability of energy systems. The applied methodology includes probabilistic safety analysis, systems reliability theory, Monte-Carlo modeling, deterministic thermal-hydraulic analysis, and probabilistic and deterministic analysis of the strength of structures, performed by application of the finite element method (see Figure). In order to carry out reliability and risk analysis of energy systems, it is important to have a reliable primary database. therefore, the project focused on collection of data on reliability of various energy systems and their components (and at the same time failures) and analysis. The collected data were primarily used for reliability analysis and modeling of probable accidents of individual energy systems (i.e., electricity, heat, and gas supply systems). The results of the accident modeling are especially important for the assessment of risk caused by systems. All energy systems are closely related and dependent on one another’s functioning. In order to evaluate the interaction of individual energy systems, internal and external failures of energy system, safety systems and barriers, an overall risk analysis of the entire Lithuanian energy system was also performed by combining main Lithuanian energy systems into a single model.
After the investigation of static and dynamic modes of Lithuanian Electrical Energy System, (EES), it was determined that in 2014 during operation modes (during largest winter, smallest winter, largest summer, smallest summer loads), EES would satisfy N-1 reliability criterion, and in many operating modes of the system, a beyond-design N-2 criterion was satisfied. After the investigation of electrical energy system, it can be claimed that reliability of Lithuanian EES is high, and the system can work steadily.
 
 
 
Simplified reliability assessment schemes for electrical energy systems: A – for heating and gas supply systems, B – for electrical energy system 
 
 
 
 
During performance of accident modeling and investigation of reliability of district heating systems (DHSs), Kaunas heating networks were selected as the main research object. Assessment of strength of DHSs pipeline and probabilistic analysis of structural integrity were performed for most dangerous sections of DHSs, selected in view of the failure statistics and results of thermal hydraulic analysis. Dependence of pipe failure probability on pressure and thickness of the pipe wall in corroded area and probabilities of rupture of separate routs of the transmission gas pipeline were determined.
During the analysis of transmission gas pipeline networks, statistical data analysis of characteristics and failures of Lithuanian transmission gas pipelines was performed. Causes and frequency of failures as well as trends of their change were identified, which were compared to gas pipeline accident statistics of other countries. One of the main causes of failure of Lithuanian transmission gas pipelines is pitting corrosion as well as joint defects, a significant part of which in connected to the manufacturing defects. After elemental analysis of metal of operated (27–45 y.) and standby (51 y.) pipes and mechanical tests, the necessary data for strength analysis of gas pipelines were obtained. After probabilistic assessment of structural integrity of transmission gas pipelines with slits, probabilities of rupture of transmission pipeline were determined, given the age and length of piping routs.
During integrated risk analysis of Lithuanian energy system (including electricity, gas, and heat supply systems), a new energy criticality methodology for critical infrastructures was implemented; it is used to assess infrastructures of mixed energy systems, while modeling functional relations between infrastructures and their components. During assessment of criticality of energy systems, it was determined that sections of one-pipe natural gas supply systems usually cause disruptions in energy needs for consumers of urban district heating supply systems (when a two-pipe system transitions into a one-pipe system). In terms of electrical system, critical components and their combinations also consist of components of the natural gas supply system, because natural gas is the main fuel used at high-capacity plants. After evaluation of security assessment methodology, developed and applied during National Research Program ATE project Lithuanian energy security research and assessment of energy security level, and energy security indicators used in it, reliability indicators of the examined energy systems, necessary for assessment of energy security, were presented.
 
In 2014, another three-year project Investigation of Lithuanian energy security and assessment of energy security level by national research program Energy for the Future that was carried out together with Vytautas Magnus University was completed. The main objective of the project was to assess Lithuanian energy security in accordance with the methodology developed in project ATE-08/2010 funded by the Research Council of Lithuania. This should maximally ensure the continuity of project ATE-08/2010 and achievement of the objectives of measure 1.1 Development and research of Lithuanian energy security analysis model.
This study is an interdisciplinary work involving modeling of energy systems, technical, economic, natural, socio-political, and other risks and analysis of their consequences, the assessment of integral energy security level. For this reason, the project has been conducted by researchers from various fields (energy, mathematics, political science, sociology).
The results obtained in the research can be summarized as follows: economic and probabilistic assessment models for energy system designed for modeling of energy disturbances and assessment of their consequences were developed. The economic model is aimed at modeling of various long-term scenarios of the energy system development and at reduction of energy production costs and effects caused by disruptions. The probabilistic model is based on probabilistic safety analysis and allows probabilistically evaluating all the possible scenarios of development of disruptions and their effects. The resulting probabilistic characteristics of consequences precondition the assessment of most dangerous disruptions for energy system, and most effective protective measures in terms of energy security.
The methodology for assessment of the energy security level, created during the research, is based on compilation of security indicators and multi-criteria analysis. Indicators include all parts of energy security and enable expressing energy security as one integral characteristic. A dynamic model for assessment of indicators, created during the research, is based on Bayesian approach, ordinary least squares methods, pair correlations, and algebraic methods, and it enables forecasting the indicator values, calculating the energy security level until the year 2020, and comparing the impact of various energy projects on the energy security level. Based on the developed technology for assessment of energy security, the Lithuanian energy security level was assessed. By means of indicators, the energy security level in the Baltic States was compared. The obtained results were used for updating the Lithuanian energy strategy.
 
2. Research on safety of nuclear power facilities
 
Researchers of the Laboratory participate in most advanced international nuclear energy research projects designated to develop new nuclear reactors and their future application not only in electricity but also heat production, and projects designated to deal with other important issues related to nuclear energy safety. Cooperation in projects, related to training and knowledge transfer to other countries’ nuclear energy infrastructure organizations, has been continued. All these activities help strengthening Lithuanian competence in the nuclear energy field, which is necessary for each country in possession of nuclear energy objects (nuclear power plants, nuclear fuel and radioactive waste storages and repositories, etc.), and executing national nuclear program.
 
Long-term institutional R&D program Scientific research of safety important processes in nuclear fission and fusion facilities
The objective of this five-year long program, initiated in 2012, is to prepare a complex safety assessment methodology for deterministic and probabilistic analysis of nuclear and thermonuclear installations with the regard of uncertainties and severe accident scenarios. Currently, there is no unified safety assessment methodology, whereas deterministic and probabilistic safety analyses separately employed for safety assessment do not estimate the aspects of interrelations. The performed work is complex; here integrated deterministic and probabilistic analysis methodology is developed and applied for safety assessment encompassing the fields of neutron kinetics, thermal-hydraulics, strength analysis, material science, mathematical modeling, etc.
 
In 2014, investigation on suitability of tools used for deterministic accident analysis of new generation nuclear reactors and nuclear fusion facilities has continued. Processes taking place in nuclear fuel assemblies during severe accidents were modeled using the experience, gained during the modelling the QUENCH experiments; in this way, validation of the created computer models was performed. Development of models for heat removal circuits of nuclear fusion devices and plasma vessels using RELAP5 computer code and modeling of mixing and combustion of hydrogen at NPP containments by means of ASTEC computer code continued. In parallel, investigations of aerosol and radioactive nuclide transport and deposition in the reactor cooling circuit and containment were carried out. In the area of strength analysis, a methodology for assessment of structural integrity of main circulation circuit of nuclear reactors and an overview of design features of nuclear fusion facilities were prepared. In addition, the assessment methodology for the structural integrity of concrete structures under the influence of static loads was prepared. In the field of material science, investigation of welding seam fatigue under the conditions of high temperature controlled deformation was carried out. All the mentioned-above studies and numerical investigations later will be combined and used to develop an integrated umbrella complex (deterministic and probabilistic) safety analysis methodology.
 
Research performed during implementation of the program and accumulated experience are important for improving the competence of Lithuanian researchers working in the field of nuclear energy, which is necessary seeking to estimate safety of nuclear power plants constructed or to be constructed both in Lithuania and neighboring countries during all NPP lifetime stages – selection of NPP, design, construction, operation, its shutdown and management of radioactive waste. Participation in design and analysis activities of nuclear fusion facilities will enable the Laboratory to keep up with the most up-to-date technologies and retain high-level scientific potential.
 
 
 
 
 Baltic Region Initiative for Long Lasting InnovAtive Nuclear Technologies
Although security of energy supply is the predominant question in all the country’s regions, nuclear energy situation in the region of the Baltic States is specific, and there are a lot of hindrances for its development. The research institutions of Poland, Lithuania, Latvia and Sweden and GE-Hitachi Company prepared and submitted project BRILLIANT Baltic Region Initiative for Long Lasting InnovAtive Nuclear Technologies of H2020 EURATOM program. The aim of the project is to establish real hindrances, which are faced by the development of nuclear energy, and prepare to overcome them. Project participants agree that individual difficult obstacles experienced by a country can be easier overcome by cooperation on the regional level. The project covers such issues as energy systems of relatively low power, impact of nuclear energy programs on microeconomics and energy security, strengthening of the capabilities in nuclear energy research and development in the region, regional cooperation in development of closed cycle technologies for nuclear waste management and nuclear fuel, public information on the benefit of nuclear energy, and strengthening of national and regional capabilities in development and application of new technologies.
 
 
 
 
 NUclear GENeration II & III Association
NUGENIA association, encompassing activities of Sustainable nuclear energy technology platform (SNETP) and competence networks NULIFE and SARNET, has continued its works in 2014. The association unites industry, research and safety organizations, executing general research and development projects in the field of nuclear energy. The association initiates and coordinates relevant research for the II and III generation nuclear reactors operated in EU states. The activity of NUGENIA is organized for eight research directions and includes directions, defined in SNETP Strategic Research Plan. In 2014, NUGENIA association became very actively involved in preparation of Horizon2020 EURATOM project proposals. For this reason, NUGENIA open innovation platform was created, where all the prepared projects are stored, and anyone connected to this platform could find information, add comments, etc. In this way, due to joint efforts of members of the association, the projects are brought to perfection. However, project proposals prepared for Horizon2020 calls may be submitted for evaluation only after obtaining NUGENIA label of the Board that guarantees the quality of the project.
LEI is a member of NUGENIA association and along with other participants is actively involved in all the eight NUGENIA association research and developments areas.
Using open access innovation platform, LEI was able to join the activity of a variety of projects under preparation. Five of seven project proposals that the specialists of the Laboratory submitted for the Horizon2020 EURATOM 2014–2015 call were prepared because of the open access innovation platform.
The association additionally organized call for projects NUGENIA+. The purpose of this call was to additionally support the NUGENIA association by enhancing its role and coordinate European research in the area of safety of nuclear devices of II and II generation, also initiate international cooperation. For this call, LEI together with other members of the association prepared and submitted another two research projects. The destiny of all the submitted project proposals will be decided in the early 2015.
 
 
 
 
 European Technical Safety Organizations Network
The researchers of the Laboratory of nuclear installation safety since 2009 have participated in the activity of European Technical Safety Organizations Network (ETSON). ETSON consists of nine member organizations: Bel V (Belgium), GRS (Germany), IRSN (France), VTT (Finland), UJV Rez (Czech Republic), LEI (Lithuania), VUJE (Slovakia), PSI (Switzerland), INRNE BAS (Bulgaria), and three associated member organizations: SSTC (Ukraine), JNES (Japan), and SEC NRS (Russia). The main objectives of ETSON are as follows:
   stand for an exchange forum on scientific research and development of nuclear energy safety;
   contribute to fostering the convergence of nuclear safety practice in Europe and beyond;
   plan nuclear safety scientific research programs and promote their implementation;
   speed up the application of the EU Directive on nuclear safety;
   cooperate in implementation of safety assessment and research projects.
 
The representatives of the Laboratory actively participate and have their representatives in all the main structures and groups of ETSON organization. Fourteen expert groups are established in ETSON network in key nuclear safety research areas. The representatives of the Laboratory participate executing all the listed activities, with the exception of electrical system analysis:
1.  Operating Experience Feedback, including Incident and Precursor Analysis;
2.  Mechanical Systems;
3.  Electrical Systems;
4.  Severe Accidents;
5.  Equipment certification for environmental conditions;
6.  Safety Fluid Systems, including auxiliary systems;
7.  Influence of Human and Organizational Factors;
8.  Probabilistic Safety Analysis;
9.  Lifetime-Management (equipment ageing);
10.  Thermal Hydraulic Analysis (Transients, Accidents);
11.  Safety concepts, Defense-in-Depth;
12.  Processes in reactor core;
13.  Emergency preparedness;
14.  Radioactive waste and NPP decommissioning.
 
Working in expert groups, the specialists prepare Technical Safety Assessment Guides. These documents present recommendations on how the institutions performing the expertise should assess safety issues related to the nuclear activity. The goal of such documents is to achieve that independent technical analysis in every ETSON member state is performed following the same rules/methodology. In this way, it is sought to coordinate and maintain a high level of nuclear safety practices in ETSON member countries. Before 2014 in all the countries, three Technical Safety Assessment Guides were coordinated and approved:
   Review of events and analysis of precursors;
   Deterministic analysis of severe accidents;
   Analysis of human and organization factors of construction of nuclear facilities and modification processes.
In 2014, new Technical Safety Assessment Guide Transients and designbasis accident analyses was prepared and approved. Also, Manual for assessment of heat carrier safety systems is prepared and will be officially published.
In the meetings of ETSON expert and coordinating groups, the participation of ETSON members in planned and ongoing EU projects, e.g., Horizon2020, is constantly discussed. At these meetings of experts from European states, one can learn about the latest ideas of performance and application of deterministic safety, risk assessment and probabilistic analysis and contribute to the implementation of new research and applied works in the field of nuclear safety analysis.
 
 
 
Safety Assessment of Innovative Reactors
International EU 7 FP project SARGEN-IV, the objective of which is to create a coordinated methodology of European countries for safety assessment of the fourth generation fast neutron spectrum reactors planned to be constructed in Europe, was officially completed at the end of 2013. In 2014, the coordination of reports on the fifth task Creation of research and development methodology for fast neutron spectrum reactor safety in the European countries was completed and finalized. The objectives of this task were:
(1)   dissemination of works executed during other tasks;
(2)   raising questions that remained open in previous tasks;
(3)   proposal of preliminary work program for scientific research and development of fast reactor safety.
LEI participated in the identification of unsolved issues related to the research of fast neutron spectrum reactor in the field of safety. Using the accumulated experience, received in applying a variety of program codes, new scientific investigations were identified, covering all processes occurring at fast neutron spectrum reactors and enabling to create and verify computer program codes, necessary for modeling those processes. LEI has also participated in preparation of recommendations for the safety analysis report on fast neutron spectrum reactors.
In this way, through cooperation with 22 EU institutions (among those LEI) participating in the project and under coordination of the Institute for Radiological Protection and Nuclear Safety (IRSN, France), all SARGEN-IV project tasks were successfully completed.
 
 
 
Assessment of Regional Capabilities for New Reactors Development through an Integrated Approach
In 2014, the works of EU 7BP ARCADIAproject have continued. This project covers two nuclear energy implementation areas foreseen in Strategic research and innovation plan of SNETP technological platform: 1) ESNII through support of construction of Generation IV liquid lead-cooled nuclear fast reactor in Romania and 2) NUGENIA through support in dealing with the remaining safety issues of Generation III nuclear reactors.
26 organizations from European countries take part in the project, which is coordinated by Romanian company INR. The project covers seven work packages, and LEI participates in five of them. The Institute is the coordinator of two of those (WP5 – Cooperation and dissemination and WP6 – Research Reactors networking for LFR technology and improved LWR safety). In 2014, two meetings took place: the first one on June 11–13, 2014 in Bologna (Italy); and the second meeting took place on October 14–17, 2014 close to Prague (Czech Republic), at the research center Rež. The focus of this meeting was the introduction of other ongoing projects in the field of nuclear energy, for example, ALLEGRO, ALLIANCE, ASAMPSA_E, SUSE, etc.
 
 
 
Nuclear Cogeneration Industrial Initiative – Research and Development Coordination
In 2014, 7BP Euratom initiated international project NC2I-R Nuclear Cogeneration Industrial Initiative – Research and Development Coordination has continued. A strategic objective of the project is to structure the European public and private sector R&D capabilities for delivering a nuclear energy cogeneration industrial object-demonstrator, which fully meets the market needs. During the project, coordinated by the Polish Nuclear Research Centre NCBJ, where research institutions as well as industry enterprises of various countries participate (a total of 21 participants), a possibility to use nuclear power plants not only for electricity but also for heat production will be assessed.
The researchers of the Laboratory conducted works foreseen under the project Task 3, Safety and Licensing, i.e. they collected material on Lithuania’s experience in implementation and development of nuclear cogeneration, as well as performed an overview of the legal framework, and prepared a chapter for the report summarizing guidelines and instructions on how to carry out a licensing process for prototype cogeneration power plant at the European level. Representatives from LEI attended the annual project coordination meeting.
 
Approval of ASTEC computer code as a mean of severe accident management in Europe
EU seventh joint research, technological development and demonstrational activity program the project CESAM Code for European Severe Accident Managementbegan on April 1, 2013. The objective of the project is to establish ASTEC code in Europe as a main mean for severe accident management in all Generation II and III European NPP (PWR, BWR, CANDU). The duration of the project is four years; it is divided into four parts:
    scientific management of ASTEC code, i.e. implementation of new models in the code;
    development of new models, taking into account information on existing physical models;
    validation of the computer code using experimental data and performance of benchmarking calculations;
    application of ASTEC computer code to analysis of power plants and during enhancement of efficiency of severe accident management, and development of typical “reference” input decks for European PWRs and BWRs type reactors.
 
18 EU institutions, including Lithuanian Energy Institute, participate in this project. LEI researchers participate in the working package Plant applications and Severe Accident Management (SAM), which is coordinated by the EC Joint Research Centre (JRC). During the project, LEI specialists together with partners will develop a model of a nuclear power plant with GE BWR4-Mark I type reactor using ASTEC code and using ASTEC and RELAP/SCDAPSIM codes will perform benchmarking calculations of spent fuel pools of a selected BWR type nuclear power plant .
In 2014, LEI specialists using module MEDICIS of code ASTEC-V2.0R3p2 developed a part of initial model of GE BWR4-Mark I type power plant. Using MEDICIS module can be simulated the interaction of molten corium with concrete. A method of lumped parameters with the averaged melt layers is used for modeling. The model developed by LEI specialists allows investigating processes of concrete ablation, melt oxidation, and emission of non-condensable gases (H2, CO, CO2) into the containment. LEI prepared initial BWR type power plant model of spent nuclear fuel pool, created using V2.0R2p2 version of ASTEC code, modified taking into account the type of power plant chosen for the investigation and changes in ICARE module of ASTEC code that occurred during transition from version ASTEC-V2.0R2p2 to V2.0R3p2. Also, the initial RELAP/SCDAPSIM model of spent nuclear fuel pool was complemented taking into account the specifics of GE BWR4-Mark I type power plant.
 
 Structure of ASTEC integral code

 
ASAMPSA_E (Advanced Safety Assessment Methodologies: Extended PSA) Advanced safety assessment methodology through application of extended Probabilistic Safety Analysis (PSA)
Since 2013, LEI participates in the Consortium, managed by the Institut de Radioprotection et de Sūreté Nucléaire (IRSN), by implementing new EU 7BP project Advanced Safety Assessment Methodology: Extended PSA). The project activity began on July 1, 2013; the duration of the project is 36 months. 28 organizations from 18 European countries are the partners of the project; several associate members also take part in the project: US-NRC, JANSI, and TEPCO.
 
In 2014, the initiated activities have continued in all five main project work packages:
    WP10: Relationship with End-Users;
    WP21: Initiating events (internal and external hazards) modeling;
    WP22: How to introduce hazards in Level 1 PSA and all possibilities of events combination? ;
    WP30: General issues regarding extended PSA scope and applications;
    WP40: Specific issues related to Level 2 PSA.
 
In 2014, by participating in the activity of all project work packages, LEI had given the most attention to the activities related to the identification of initial events (internal and external hazards) and literature references covering project activities as well as questionnaire for beneficiaries and analysis of the collected information. A special seminar was organized to consider the responses of beneficiaries to the questionnaire for the project ASAMPSA_E, where ~60 participants from various European and other countries (e.g., Japan, North Korea, Ukraine, and USA) took part. At the seminar for beneficiaries, the most attention was given to discuss the responses, taking into consideration the earlier prepared questionnaire. The questionnaire for NPP operators and regulators was made up of almost 100 questions on advanced safety assessment methodology applying extended probabilistic safety analysis. The attention was also focused on the analysis of various external extreme events (meteorological, seismic, and other events), but at the same time, discussion of activities carried out in separate project packages took place. At the end of the seminar, surveys of responses to the questionnaire were formulated, and the recommendations for further execution of the project were prepared. In continuing the work, it is planned to take into account all 64 recommendations summarized during the seminar. Moreover, it was decided that in WP21 work package, LEI would be responsible for coordination of the area of assessment of meteorological events. In WP22 work package, AMEC and LEI are together responsible for work area: Link between external initiating events of PSA and NPP design basis conditions. In other work packages, LEI together with other organizations also linked their activities to cooperation in ETSON PSA expert group and with preparation of IAEA documents.
 
Participation in this project revealed that recently, a lot of research institutions that were not even directly related to NPP (e.g., University of Vienna) are focused on probabilistic assessment of events and safety, development of corresponding methods, and wide application of them ensuring and demonstrating NPP safety. Participation in such European state projects as ASAMPSA_E allows immediate access to the latest ideas on performance and application of risk assessment and probabilistic analysis and contribution to new scientific and applied research in the field of safety analysis. In the future, it will be sought to develop and intensify bilateral cooperation with ASAMPSA_E project participants.
 
MATTER MATerials TEsting and Rules
EU 7BP project MATTER has continued (it has begun on January 1, 2011). During implementation of the project, it was aimed to carry out detailed studies on the behavior of materials under the operating conditions of IV generation reactor. The researchers from the Laboratory of Nuclear Installation Safety and the Laboratory of Materials Research and Testing participate in the study. In 2014, studies on fatigue of P91 cross-weld specimens were carried out, and values of welded joint coefficient in air at the temperature of 550 °C were determined, taking into account given values of strain. These studies were executed by the researches of the Laboratory of Materials Research and Testing in air on P91 cross-weld specimens.
 
 
The model of finite elements with transverse welded joint

 Forecasting of damaged section of a welded sample at 0.5% deformation
 
  
 
Parallel to these experimental studies, numerical fatigue studies of a welded sample were performed applying the finite element method. Results of finite element analysis allowed a more comprehensive understanding of the behavior of material in case of specimen fatigue. The numerical study of fatigue used finite element program Cast3m created and still undergoing development at the Atomic Energy Centre CAE, France. Using this software a finite element model with a cross-weld was created. Representative results of the fatigue damage accumulation as the cycle number grows at strain range of 0.7% are presented in the figure below. These studies were executed by the researchers of the Laboratory of Nuclear Installation Safety.
                     
3. Transfer of knowledge on nuclear safety and organization of training
 
 European Nuclear Safety Training and Tutoring Institute
ENSTTI was established in 2010. This Institute was established by ETSON organizations, urged by the Institute for Radiological Protection and Nuclear Safety (IRNS). The founders of ENSTTI are IRSN (France) and LEI (Lithuania). Currently, the members of the Institute besides the mentioned organizations are also GRS (Germany) and Bel V (Belgium). The Institute is closely related to the European Technical Safety Organization Network ETSON and technical safety organizations participating in this EU community. The objective of ENSTTI is to provide training, consulting and practical services in the assessment of nuclear and radiation safety. It is intended for technical support organizations to share their experience on enhancing nuclear safety, dissemination of news and practical experience in the field of nuclear safety culture.
 
 
Organizations participating in ENSTTI activity 
 
 
 
As every year, in 2014 ENSTTI organized a traditional four-week summer introductory nuclear energy safety training course that took place on June 11 – July 6 at GRS research center in Germany. The researchers of the Laboratory delivered lectures on the strategies of dismantling of nuclear power plants and the issues of dismantling Ignalina NPP. Yet, the ENSTTI activity is not limited only to such preparatory introductory courses. From 2013, by the order of the European Commission, a two-phase training project Training and tutoring for experts of the Nuclear Regulatory Authorities and their technical support organizations has been implemented.
 
 
 
 Participants and lecturers of training course Criticality safety and thermal hydraulics
(LEI, May 16, 2014)
For the first part of the project (LOT1) Nuclear safety regulation, licensing and enforcement, a consortium consisting of institutions regulating nuclear safety and technical safety organizations has been established. Besides the four afore-mentioned organizations constituent of ENSTTI, consortium involves: FANC (Belgium), ASN (France), CSN (Spain), BBM (Austria), RCR (Czech Republic), SSTC (Ukraine). For the second part of the project (LOT2) Nuclear safety assessment and inspection, another consortium consisting of technical safety organizations that besides ENSTTI includes CIEMAT (Spain), ENEA (Italy), RCS (Czech Republic), VUJE (Slovakia) and SSTC (Ukraine) has been established. The trainings are aimed at developing countries and countries developing (or planning on developing) nuclear energy: Tunisia, Indonesia, Malaysia, Jordan, Belarus, Georgia, Vietnam, Morocco, Philippines, Ukraine, Armenia, Egypt, Mexico and Brazil. Listeners from other countries can also attend the course upon paying the participation fee. During the course, specific issues on nuclear installation safety are addressed; the courses are aimed at experienced listeners, and the specialists delivering the lectures to them have to be experts in respective fields.
 
 
 
Participants and lecturers of training course Regulatory framework of decommissioning of nuclear facilities (LEI, December 8, 2014) 

 
In 2014, researchers from LEI delivered lectures in six training courses, two of which were hosted by LEI:
1.    Radiation protection and containment systems, Paris, France, March 17–21.
2.    Aging and mechanical analysis, Köln, Germany, March 24–28.
3.    Criticality safety and thermal hydraulics of reactors, Kaunas, Lithuania, May 16–20.
4.    Safety of nuclear fuel cycle, Marcoule, France, September 08–19.
5.    Safety of nuclear reactors I, Bologna, Italy, November 17–21.
6.    Regulatory framework for decommissioning of nuclear facilities, Kaunas, Lithuania, December 08–12.
 
Active participation of LEI specialists in the activity of this project helps to gain experience in organizing similar courses and enhance their qualification. Such experience can be useful upon the initiation of construction of Visaginas NPP, when its new employees and employees of overseeing organizations will have to be trained.
Transfer of the European Regulatory Methodology and Practice to the Nuclear Safety Authority of Belarus
In2014, works of BY3.01/09 (BE/RA/07-A) project Development of technical cooperation in nuclear safety in the field of assistance to regulatory authorities have continued. The objective of this project is to support Belarus Gosatomnadzor in nuclear safety regulation activities, certifying the license application for Belarus NPP under construction, also training Belarus experts to properly perform the review of documents related to nuclear activity. In 2014, LEI executed works under task 2.2 Review of selected safety issues addressed in the preliminary safety analysis report. Besides LEI, this work involved experts from IRSN (France), GRS (Germany), STUK (Finland) and SSTC (Ukraine). The representative of IRSN was in charge of the works. EU experts addressed individual safety issues selected during implementation of the earlier project. The analyzed results were discussed with experts from Belarus Nuclear Safety Regulating Institution and the workers from Joint Institute for Power and Nuclear Research (SOSNY), carrying out a review of Belarus NPP safety analysis report. Belarus specialists were trained to address technical issues and how to prepare conditions for the validity of license. LEI addressed issues related to the assessment of plane crash possibility, resistance of reactor buildings to earthquake, resistance of reactor containment to external impact, and issues of cooling of spent nuclear fuel pools. During execution of work, also IAEA seminar was organized for training staff of Belarus Gosatomnadzor. A representative of LEI delivered lectures on issues of emergency preparedness. During implementation of the project, conditions for license validity were prepared for all the addressed issues, which require presenting additional safety justification information. Belarus Gosatomnadzor called a work group of 27 local specialists that took part in the project and learned. These specialists will review safety analysis reports in the future and will prepare license conditions for both the first and the second reactors of Belarus NPP.
Such support to the neighbor country is necessary in order to ensure timely and effective supervision of the constructed nuclear power plant by Belarus nuclear regulation institutions. This is very important not only for Belarus, but also for Lithuania (at the border of which this power plant is constructed) and for the entire Europe.
 
FUSENET the European Fusion Education Network
FUSENET association is the European Fusion Education Network, uniting European universities, research centers and industrial organizations, participating in scientific research of thermonuclear fusion. ITER international organization also belongs to this network. Since mid 2013, LEI has been a member of this association. Participation in this activity provides a possibility for doctorate students and junior researchers to more effectively participate in different trainings and exchange programs in all organizations of Fusenet association. On February 4, 2014 in Barcelona (Spain), the 3rd Fusenet General Assembly meeting took place, where a representative from LEI E. Urbonavičius participated for the first time. Business and financial reports of the year 2013 and work plans for 2014–2015 were discussed at the meeting; new Fusenet council members have been approved.
 
 
 

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