중수로원전에서 냉각재상실사고시 출력펄스 및 열수력 거동해석

One of the major characteristics of CANDU type reactor is the positive void coefficient of reactivity. Therefore, in the event of the LBLOCA (large break loss of coolant accident) there is a drastic increase in reactor power (power pulse) due to the positive void reactivity feedback. MARS-KS-CANDU (Multi-dimensional Analysis of Reactor Safety-KINS Standard-CANDU) code has been developed by KINS to estimate and evaluate the thermal hydraulic behavior of nuclear power plants. The purpose of this study is to calculate the thermal hydraulic behavior of the CANDU reactor system during the LBLOCA using MARS-KS-CANDU to evaluate the influence of the power pulse. For the analysis of the accident, major systems of the CANDU reactor were considered in the modeling including the nuclear fuel channel (380 channels), the heat transport system, the main steam system, the emergency core cooling system and so on. In order to evaluate the influence of power pulse in early stage of the accident, the sensitivity study was conducted with various break sizes.