Projects / Programmes
January 1, 2015
- December 31, 2019
| Code |
Science |
Field |
Subfield |
| 2.13.00 |
Engineering sciences and technologies |
Process engineering |
|
| 2.03.00 |
Engineering sciences and technologies |
Energy engineering |
|
| Code |
Science |
Field |
| T160 |
Technological sciences |
Nuclear engineering and technology |
| Code |
Science |
Field |
| 2.03 |
Engineering and Technology |
Mechanical engineering |
nuclear safety, thermal hydraulics, severe accidents, heat transfer, mass transfer, fluid mechanics, structural integrity, fracture mechanics, probabilistic safety assessment
Researchers (23)
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
0106 |
Jožef Stefan Institute |
Ljubljana |
5051606000 |
90,753 |
Abstract
The research topics of the program Reactor Engineering are: heat and mass transfer, severe accident phenomena, structural integrity and ageing, and probabilistic safety assessment.
HEAT AND MASS TRANSFER
1. Basic heat and mass transfer phenomena
— Single-phase turbulent heat transfer will be modelled with Direct Numerical Simulation and Large Eddy Simulation.
— Two-phase flow will be modelled with interface tracking/sharpening models and with two-fluid models.
— An experimental facility will be used for velocity and temperature measurements in the flow boundary layer and on the interface in gas-liquid two-phase flow.
2. Heat and mass transfer in reactor systems
— Thermal-hydraulic transients in the coolant system of pressurized water reactors will be simulated with best-estimate system codes and Computational Fluid Dynamics (CFD) codes, in part coupled with reactor physics models. Water hammer transients will be analysed with coupled structural and thermal-hydraulic models.
— Phenomena in advanced liquid metal or gas cooled reactors will be simulated, as well as thermal-hydraulics in the tokamak of the fusion reactor.
SEVERE ACCIDENT PHENOMENA
— Hydrogen combustion in containment will be simulated using CFD and lumped-parameter codes.
— Within studies of vapour explosions (due to interaction between molten reactor core and coolant), melt-water and melt-sodium interactions will be investigated.
— Coolability of debris bed, resulting from accumulation of molten core on the reactor cavity floor, will be modelled.
STRUCTURAL INTEGRITY AND AGEING
— To improve understanding of the ageing processes, we will build constitutive and computational models that account for corrosion and irradiation effects at microstructure level.
— A multi-scale simulation tool assessing the combined effects of irradiation, corrosion and dynamic loads on damage initiation in steel alloys will be developed.
PROBABILISTIC SAFETY ASSESSMENT (PSA)
— A new method that will contribute to improved risk modelling of nuclear power plants will be developed. The focus will be on extension of the PSA methodology with consideration of extreme external events and their combinations in risk analysis.
— Integration of the deterministic and probabilistic safety analyses will be investigated. Analyses of implications of uncertainties on risk-informed decision making will be done.
Significance for science
All planned research is either part of current projects within the 7th Framework programme of the European Commission or of projects in preparation for the Horizon 2020 call. This confirms the general importance of the proposed program for the development of science.
HEAT AND MASS TRANSFER
1. Basic heat and mass transfer phenomena
Direct Numerical Simulation of natural and mixed convection heat transfer in simplified fuel channels will represent an original achievement. The created databases will be used for further development of turbulent models for less accurate simulations in realistic geometries.
The mathematical description of turbulent two-phase flow, which will be based on two-fluid model and will be able to perform tracking of large interfaces and neglect small ones, will represent a research achievement. A coupled model applicable for realistic flows will represent a step forward in the development of thermal-hydraulic computer codes.
Other research in the field of heat and mass transfer will contribute to the development of science on the following topics:
— influence of flow dynamics on heat transfer enhancement at multiple jet impingement;
— complex turbulent flows in fuel bundles with mixing vanes, including prediction of flow pulsations;
— boiling flow at high void fraction, including prediction of critical heat flux and transition to film boiling;
— modelling of flow phenomena in separated and mixed two-phase flows.
The experimental research of heat transfer and fluid flow will provide new experimental data, which are essential for better understanding of governing heat transfer and fluid flow mechanisms in single and two-phase flow systems.
2. Heat and mass transfer in reactor systems
Simulations of transients in reactor coolant systems will contribute to the development of methods for multi-dimensional coupled deterministic safety analyses of nuclear reactors on the system scale.
Studies of water hammer will contribute to the modelling of fast transients, in particular those initiated by sudden vapour condensation.
SEVERE ACCIDENT PHENOMENA
Research on hydrogen combustion will contribute to the study of the influence of turbulence on flame propagation.
Research on vapour explosions will contribute to the knowledge on the interaction between fluids with high temperature difference.
Research on debris coolability will represent a contribution in the field of heat transfer from a solid with internal heat generation.
STRUCTURAL INTEGRITY AND AGEING
Research in structural integrity and ageing will contribute to the development of following topics:
— assessment of damage initiation in steel alloys due to combined effects of irradiation, corrosion, dynamical loads and microstructure;
— plastic strain localization within polycrystalline aggregate due to dynamical stress loadings;
— macroscopic material response in relation to properties on smaller length scales;
— assessment of (thermal) fatigue damage in metals and alloys.
PROBABILISTIC SAFETY ASSESSMENT
Research in probabilistic safety assessment (PSA) will enable the following advancements in the development of science:
— evaluation of consequences of extreme external events and their combinations on safety of complex systems;
— integration of deterministic methods and probabilistic safety assessment as a standpoint for risk-informed decision-making.
Significance for the country
The results of all aspects and proposed fields of research and their mutual interrelation and complementarity are a necessary theoretical basis for safety analyses, related with the safe and stable operation of the Krško nuclear power plant, as well as for the execution of the most demanding expert tasks for the Krško NPP and the Slovenian Nuclear Safety Administration. The results thus directly and indirectly contribute to the level of the safety culture in Slovenia.
In more detail: research in the field of heat and mass transfer and severe accidents, including combined research with structural integrity and ageing and probabilistic safety analyses, are especially important for interdisciplinary analyses and expert tasks that involve transient phenomena and hypothetical accidents. In this way, the research contributes to the long-term availability of competitive electrical energy, and to the protection of the population and the environment.
Research in the field of structural integrity and ageing enables more accurate prediction of the lifetime of important components of the Krško NPP, which has a direct influence on the availability of safe electricity. At the same time, the purposes of the research are set to enable direct knowledge transfer in support of the life-time extension of the existing plant and the planned construction of the new nuclear plant in Slovenia. The acquired knowledge will also be usefull in the process and mechanical industries.
Research in the field of probabilistic safety assessment and risk contributes to the establishment of risk-informed decision-making and accelerates the development of regulations and standards based on risk analyses.
Most important scientific results
Annual report
2015,
interim report,
final report
Most important socioeconomically and culturally relevant results
Annual report
2015,
interim report,
final report
