Projects / Programmes
Modeliranje vpliva snovskih lastnosti na parno eksplozijo (Slovene)
| Code |
Science |
Field |
Subfield |
| 2.03.04 |
Engineering sciences and technologies |
Energy engineering |
Energy systems |
| Code |
Science |
Field |
| 2.11 |
Engineering and Technology |
Other engineering and technologies |
Researchers (11)
Organisations (1)
| no. |
Code |
Research organisation |
City |
Registration number |
No. of publicationsNo. of publications |
| 1. |
0106 |
Jožef Stefan Institute |
Ljubljana |
5051606000 |
90,753 |
Significance for science
One of the most important remaining issues in core melt progression during a severe nuclear reactor accident are the likelihood and the consequences of a steam explosion, which may occur when the hot core melt comes into contact with the coolant water. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. One of the outcomes of the OECD SERENA Phase 1 programme is that the calculated loads of ex-vessel steam explosions may also exceed the capacity of typical reactor cavity walls. Due to the large scatter of simulation results, reflecting the uncertainties in steam explosion understanding, modelling and scaling, the safety margin for ex-vessel steam explosions can not be quantified reliably. Based on the research results we will be able to more reliably predict the pressure loads during a steam explosion.
Within the project we investigated and modelled the melt material influence on the steam explosion. Experiments have revealed that there is a significant influence of the melt material properties on the fuel coolant interaction process. We were able to explain why the energy efficiency of steam explosions with simulant alumina melt is one order of magnitude larger than with prototypic oxydic corium melt. The main reason for the experimentally observed differences is the different melt droplet solidification during the premixing phase. Therefore we developed a melt droplet solidification model and a criterion for the droplets fine fragmentation during the explosion, which considers the influence of the droplets surface conditions on the droplets fine fragmentation. The developed solidification influence model was incorporated in the advanced code MC3D, it was validated, and the optimal values of the model parameters were determined. Thus we obtained a simulation tool, which enables more realistic simulations of reactor conditions and consequently a more reliable estimation of the vulnerability of nuclear power plants to steam explosions.
The results of the research project present a scientific contribution in the field of steam explosion research related to nuclear safety. They significantly contribute to the improved understanding and modelling of the complex steam explosion phenomenon and to the interpretation of the results of fuel coolant interaction experiments.
Significance for the country
The results of the research project form the 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. The importance of research in the field of nuclear safety (which is also relevant for Slovenia) has especially been shown by the accident at the Fukushima nuclear power plant in Japan (March 2011), where it was confirmed, that the prediction of the further course of an accident is important for adequate mitigation and limiting of the consequences.
The results of the project enable the assessment of the likelihood and the consequences of a steam explosion in the Krško NPP. The research contributes to creating, keeping and improving of own technical knowledge, makes independence on foreign expertise in support of safe Krško NPP operation and helps the regulatory body in the inspection of Krško NPP operation and maintenance. The research enables also the cooperation in international research programs, within which we have access to the latest scientific knowledge, to experimental data and to computer programs. All this contributes to the increase of the economic growth and the increase of the competitive position of Slovenia.
Most important scientific results
Annual report
2009,
2010,
2011,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2009,
2010,
2011,
final report,
complete report on dLib.si
