Numerical simulation of gas entrainment phenomena in sodium-cooled fast reactor with high-precision interface-tracking method

Ito, Kei; Kunugi, Tomoaki*; Koizumi, Yasuo*; Ohno, Shuji  ; Ohshima, Hiroyuki

One thermal-hydraulics issue in a sodium-cooled fast reactor is gas entrainment (GE) phenomena. The authors have developed a numerical simulation code for gas-liquid two-phase flows with a high-precision interface-tracking method. This simulation code employs an unstructured mesh scheme to model structural geometries accurately. As for the interface-tracking method, the authors have developed an innovative method based on the high-precision volume-of-fluid method. As a result of fundamental validations, the developed code shows superior simulation accuracy to conventional codes. For example, with the developed second-order interface gradient calculation method, the developed code provides 20-30% smaller simulation error than the original PLIC method for the slotted-disk revolution problem. The GE phenomena itself are also simulated with the developed code and the quantitative agreements of entrained gas flow rates are obtained between the simulation results are the experimental data.