국제 표준 ISP-47 TOSQAN 실험 전산 해석 및 응축벽 조건 변화에 따른 민감도 분석

This study investigates the effects of wall temperature and condensation region variations on internal flow characteristics and helium distribution in the ISP-47 TOSQAN experiment. The time t = 16000s during Steady-State 4 of the ISP-47 TOSQAN experiment was selected as the initial condition for the simulation. Sensitivity analyses were performed by varying the condensation wall temperature and condensing wall region. The results revealed that in configurations with narrow condensation regions, helium volume fraction was primarily influenced by steam condensation driven by wall temperature. In contrast, when the condensation region expanded, enhanced natural circulation led to more uniform helium mixing. These observations were obtained through empirical assessment based on numerical simulations, offering insights into the relative importance of condensation-driven helium enrichment versus flow-induced mixing. This study provides a basis for understanding gas stratification behavior under variable boundary conditions in severe accident scenarios.