Estimation of break condition at small pipe-break loss-of-coolant-accident of PWR plant using quantitative input-output characteristics of components

Quantitative representations of input-output characteristics for both flow rate and specific enthalpy of coolant in the components of PWR (Pressurized Water Reactor) primary side are derived based on a simple PWR primary side model. An estimation technique of break condition at small pipe-break loss-of-coolant-accident is proposed using the quantitative knowledge representations. The applicable break size of the technique is considered as 0.05 to 0.25 ft² (4.64×10^-3 to 2.32×10^-2m²) by the results of several computer experiments, where the reference data are obtained using a safety analysis code RELAP4/MOD6.