MAIN RESEARCH AREAS OF THE LABORATORY:
– reliability of power plant facilities: research of metal aging processes and degradation of properties due to the impact of operational factors;
– development and research of multifunctional materials and composites;
– testing of materials, assessment and analysis of their qualitative indicators.
RELIABILITY OF POWER PLANT FACILITIES: RESEARCH OF METAL AGING PROCESSES AND DEGRADATION OF PROPERTIES DUE TO THE IMPACT OF OPERATIONAL FACTORS
The Laboratory carries out research aimed at the investigation of processes of ageing of steel and special alloys that are used as the constructional elements for power plants and to study patterns of aging processes, solve issues regarding control of these processes and service life. Applying mechanical tests, X-ray Diffraction (XRD) and elemental composition analysis, as well as optic and scanning electron microscopy, structural and property changes of steel and non-ferrous metal alloys are studied. Experimental and numerical methods are used to predict operational reliability taking into account material ageing processes and other operational factors. The implementation of this work focuses on the investigation of the fundamental physical and chemical phenomena affecting structure and properties of metals. In this research direction, researchers of the Laboratory participate in long-term institutional scientific research and experimental development programs: Scientific research of safety important processes taking place in nuclear and thermal nuclear facilities (Task 9) and Research of processes of nuclear power plant operation decommissioning, nuclear waste and spent nuclear fuel management and radiation impact analysis (Task 5).
In 2014, researchers of the Laboratory together with researchers of the Laboratory of nuclear installation safety participated in the project Reliability and Risk Research of Lithuanian Energy Systems of the program Energy for the Future funded by theResearch Council of Lithuania. In this project, the analysis of causes of gas-main pipeline failures and ageing processes was carried out along with the research on pipe metal properties after long-term operation.
Works, initiated in 2010 with JSC GEOTERMA, for performance of analysis of processes taking place in systems of Absorption Heat Pumps (AHP) and consultations, regarding maintenance of stable parameters of lithium-bromide solution in heat pumps and other technological issues, have continued.
In 2014, the project Service life assessment model for new generation steel funded by theResearch Council of Lithuania was launched. The objective of the work is to investigate structural changes in steel under high temperatures and their influence on the mechanical characteristics and fracture parameters. The structural changes will be determined after the investigation of phase transformations of steel structure, related to diffusion processes occurring under the influence of temperature, by assessing the evolution of steel carbides and changes of parameters in their crystal lattice.
Hydride reorientation under tension at the top of notch in fuel cladding pipe, simulating defect
The Laboratory continues the research initiated in 1998 regarding degradation impact of hydrogen and hydrides on zirconium alloys. Since 2011, the Laboratory has been participating in the new research project Evaluation of Conditions for Hydrogen-Induced Degradation of Zirconium Alloys during Fuel Operation and Long-Term Storage coordinated by the International Atomic Energy Agency (IAEA).
The objective of this work is to develop experimental procedures in order to assess conditions of hydride cracking in zirconium alloy fuel cladding and threshold stress intensity factor values and temperature limits, under which failure of fuel cladding may occur. By applying controlled hydriding, special construction samples were made of zirconium alloy fuel cladding, in which by changing stress levels, hydride cracking process under given temperatures was studied. The research is important for solving the issues of ensuring safe operation of nuclear power plants and assessing the resistance of fuel cladding to the hydride cracking during long-term storage of spent nuclear fuel.
Works of the project MATerials TEsting and Rules (MATTER) of European Union 7th Framework Programhave continued. The project was launched in2011 together with the researchers of the Laboratory of Nuclear Installation Safety. Fifteen work packages were formed according to the project tasks. The Laboratories participate in two working groups: Manufacturing and welding and Testing activities in support of design. Within the scope of the project, a new research on material behavior in the operational conditions of IV generation reactors was initiated. These investigations seek to determine criteria for safe application of materials in nuclear components, operating under high temperatures, taking into consideration the specifics of material ageing mechanisms. One of the main objectives of this experimental research is to identify the allowable fatigue limits and weld joint coefficient values of heat resistant steel welding seams, operating under high temperature and manufactured by applying up-to-date welding technologies. Taking into account the requirements for modern experimental procedures, a research methodology was developed for carrying out the experiments. The fatigue tests were performed at 550 °C under strain controlled conditions using dynamic testing machine Instron (Model 8801, 100kN) with a special testing equipment and software for experiment control. The resulted data of this work, describing the behavior of welding seams at high temperatures, are important for predicting their lifetime in the reactor components and in assessing the suitability of welding technologies in continuation of further research on the welding materials and processes caused by operational factors in the nuclear components. At the final stage of works of this project, the reports related to methodology for evaluation of fatigue resistance of welding seams, their durability and determination of weld joint coefficients, taking into account the given strain values, were prepared. A part of these experimental data is submitted and included in MatDB database.
DEVELOPMENT AND RESEARCH OF MULTIFUNCTIONAL MATERIALS AND COMPOSITES
In 2014, a subsidy-funded scientific Research of impact of nano-sized modified admixtures on the structure of composite materials was launched. The work aims to investigate the structure of natural and synthetic layered nano silicates and to optimize the modification methodology; it also seeks to research the impact of modified silicates and complex nano-sized admixtures on themorphology of cement composite materials. The objective of this work is to investigate the impact of change of parameters of layered silicate crystal lattice on the structure of cement composite materials. It is also important to investigate the dependence of morphological change of cement binding materials on the complex nano admixture introduced to the composition, which consists of hydrophilic and hydrophobic nano-silicate. Simultaneous complex effect of these additive, taking into account their mutual relationship, will enable expanding the limits of use of nano admixtures, while optimizing the composition of composite cement binding materials.
Applying methods of x-ray diffraction analysis, simultaneous thermal analysis, scanning electron and transmission electron microscopy, and nitrogen sorption, modification methodology of layered phyllosilicates and structure of modified natural montmorillonite and synthetic gyrolite with intercalated Na + ions were specified and optimized. The obtained results are the first step in development of composite material, the components of which would be replaced by alternative and environmentally friendly materials, yet the structural properties of the material would remain unchanged.
SEM images of synthetic original and modified gyrolite
The final work stages of the European Union 7th Framework Program project Nanotechnology Enhanced Extruded Fibre Reinforced Foam Cement Based Environmentally Friendly Sandwich Material for Building Applications (FIBCEM), launched in 2012, have continued.
Curves of thermal analysis of silicates and testing equipment
Ten partners from five European countries: Italy, Spain, United Kingdom, Denmark and Lithuania participate in FIBCEM project, which upon successful cooperation have implemented the objective of FIBCEM project and developed a perspective, low-energy consuming technology for production of foam cement based roofing tiles and sidings enabling to reduce emissions of carbon dioxide into the environment. During implementation of this project, the researchers of the Laboratory did not only supervise the fourth work group (WP4) with the work objective to create a methodology for modification of phyllosilicates, but also worked together with other work groups, researchers from the United Kingdom BATH University and Technical University of Denmark implementing scientific research set in the program, related to specific features of nano-sized materials. In 2014, during the final reporting meeting of the project participants in Aalborg, Denmark (Cembrit), the researchers of the Laboratory presented nano-bentonite modification technology ready for the production process, which was successfully applied by the project partner Italian company Laviosa Chimica Mineraria.
TESTING OF MATERIALS, ASSESSMENT AND ANALYSIS OF THEIR QUALITATIVE INDICATORS
Researchers of the Laboratory provide accredited Laboratory services; perform material testing and assessment of their quality (the Laboratory complies with the requirements of LST EN ISO/IEC 17025). As a result of successful collaboration with economic entities, the Laboratory carries out research and provides consults on the quality issues of product manufacturing.
Laboratory is accredited to carry out tests on:
• plastic pipes,
• pre-insulated pipes,
• building mortars,
• refractory materials and products.
Services to customers. Testing of plastic pipe (determination of resistance to internal pressure)
In 2014, as the result of the work of the researchers of the Laboratory, four articles were published in journals listed in Thomson Reuters Web of Science Core Collection database. Two papers were presented at international conferences.
|Laboratory of Material Research and Testing accreditation and other certificates
||Institution which issued the documen
||Accreditation certificate No LA.01.006
Actual scope of Accreditation
|Medžiagų tyrimų ir bandymų laboratorija atitinka LST EN ISO/IEC 17025:2006 reikalavimus ir akredituota atlikti statybinių skiedinių, plastikinių vamzdžių, izoliuotų vamzdžių ir ugniai atsparių gaminių bandymus.
||Lithuanian National Accreditation Bureau