To improve the determination of heat and mass transfer in fuel-coolant interaction codes, appropriate knowledge of the conditions inside the melt droplets is needed. A simplified mathematical model for the determination of the melt droplet conditions is introduced, considering the material physical properties of the droplets. Since the computational demand of the mathematical model would significantly increase the overall computational time of the fuel-coolant interaction codes, a simplification based on the temperature profile approach is presented. The model is simple enough to be practical for the implementation into computer codes and complex enough to consider adequately the material properties.
COBISS.SI-ID: 25895719
A new approach for safety system unavailability reduction by optimizing the related test and maintenance schedule suggested by the technical specifications in the nuclear industry is presented. Two additional insights, ageing data uncertainty and test and maintenance costs, are considered along with unavailability insights gained from the probabilistic safety assessment for a selected standard safety system.
COBISS.SI-ID: 25970983
The uncertainty of experimental data as well as uncertainty of key parameters of a divertor computational model is considered. The accuracy of computational model was demonstrated on the cyclic high heat flux divertor experimental case.
COBISS.SI-ID: 25958951
A successful numerical modeling of convective heat transfer with or without phase change is highly dependent on the prediction accuracy of the flow conditions in the wall boundary layer. Experimental measurements on this scale have become available only recently. The results are intrinsically promoting the use of different wall functions, the adoption of local heat transfer mechanisms and bubble dynamics. In this context, turbulent boiling flow in a vertical rectangular channel with one heated wall was simulated. The experimental data adopted in our study refer to the 2D instantaneous velocity field measurements and their derivatives in the near wall region. Measurements were carried out at Texas A&M University (USA).
COBISS.SI-ID: 25589287
Rapid depressurization of a vertical pipe filled with hot liquid water was analyzed with the in-house computer code WAHA. High initial pressure and temperature that increases uniformly from the bottom to the top of the pipe were set as initial conditions. The simulation of the rapid opening of the valve at the top of the pipe has shown important advantages of the computer code WAHA compared to the computer code RELAP5 that is frequently used for analyses in nuclear thermal hydraulics.
COBISS.SI-ID: 26147367