Two computer codes for neutron transport simulation were compared: the French code TRIPOLI and the American code MCNP. Similar result of TRIGA criticality benchmark model were obtained with both codes for the research reactor TRIGA Mark II, located at the Jozef Stefan Institute reactor center.
COBISS.SI-ID: 28243751
Air-water churn flow in a vertical pipe using two-fluid modelling with interface sharpening was simulated with a three-dimensional description. The unsteady Reynolds-averaged Navier Stokes approach was used to simulate the transient behaviour of the churn flow. The turbulence for each of the phases was modelled by a two-equation eddy viscosity model. The accuracy of the simulations was evaluated by comparing the simulated flooding wave amplitudes and frequencies with experimental data from the literature.
COBISS.SI-ID: 28827431
A Pressurized Water Reactor ex-vessel steam explosion study was carried out with the MC3D code in conditions, defined within the OECD SERENA reactor exercise. The axial melt release case was simulated in two dimensions, whereas the side release case was simulated in three dimensions (3D). In reactor calculations, the largest uncertainties in the prediction of the steam explosion strength may be expected due to the large uncertainties related to the jet breakup. Therefore, the influence of jet breakup modelling on the fuel coolant interaction was analysed. The results have shown that the pressure loads on the cavity wall significantly depend on the release location. The 3D modelling approach enables the study of realistic scenarios. Thus, for reliable reactor simulations, it is important that the fuel coolant interaction codes have adequate 3D modelling capabilities.
COBISS.SI-ID: 27690023
A recently developed approach for the generation of space-continuous and time-dependent temperature fields has been employed in this study to reproduce fluid temperature fields of a T-junction case study. A detailed analysis of the one-dimensional (1D) and three-dimensional (3D) thermo-mechanical response of the piping has been performed under different mechanical boundary conditions and complex thermal loads arising in fluid mixing in T-junctions.
COBISS.SI-ID: 28134183
Combined loss of off-site power (LOOP) and station blackout (SBO) events were analysed with deterministic and probabilistic safety analysis codes. The analysis was done for different time delays between the LOOP and SBO events. Results show that the time delay of the SBO after the LOOP leads to a decrease of the core damage frequency (CDF) from the SBO event tree. The reduction of the CDF depends on the time delay of the SBO after the LOOP event. The results show the importance of the safety systems to operate immediately after the plant shutdown, when the decay heat is highest.
COBISS.SI-ID: 28780071