The conservative method on the analysis of loss-of-coolant accidents for the HANARO fuel test loop was established based on the guide of evaluation method for the emergency core cooling systems of pressurized light water reactors. The evaluation models, the Moody model for discharge rate calculation and the Baker-Just model for water-metal reaction calculation, were used. In order to calculate conservative peak cladding temperatures for accidents the multipliers to the correlations of heat transfer coefficients in the MARS were also introduced. Consequently it is found that the maximum peak cladding temperature predicted by using the conservative method is sufficiently greater than that calculated by using the best-estimated models.

The main objective of this paper is to search whether containment vessel's best pressure may increase until how long when loss of coolant accident (LOCA) happened in containment vessel of Ulchin nuclear power plant 1 and 2. Another goal of this research is to find the influential factors that increase containment vessel pressure. Model for this research is Ulchin nuclear power plant 1 with 10 cycles. Data were collected by simulator of Ulchin nuclear power plant 1 and design of experiment was used for data analysis. For the experiment, seven factors that are going to influence in containment vessel pressure were chosen. It was found that fatter which influences in early rise of containment vessel pressure after LOCA is only explosion size. Also, containment vessel's best pressure (3.74 bar.a) was much lower than limit (4.86 bar.a) of FSAR (Final Safety Analysis Report).