Quantitative similarity analysis of small-break loss-of-coolant accident scenarios

Classifications of small-break loss-of-coolant accidents based on objective quantitative similarity analysis are proposed. Accident scenarios were simulated in a two-loop pressurized water reactor plant with the RELAP5/MOD3.1 computer code for break sizes ranging from 1.27 cm (0.5 in.) to 15.2 cm (6 in.), with different availability of auxiliary feedwater system or reactor coolant pump trip delay. Similarities between different accident simulations were evaluated by comparing relevant time-dependent parameters with fast Fourier transform and correlation methods. Quantification of similarity between accident simulations could eventually lead to further development of the Code Scaling, Applicability and Uncertainty methodology.