Software CaPpaPI for probability calculations for thermomechanics of fuel rods

There was developed software CaPpaPI (Complex of Programs for Probability Investigations) for probabilistic calculations that implements the algorithm of probability calculations of fuel rods on the base of Monte-Carlo method using codes START-3 and RAPTA-5.2 and thermo-hydravlic conditions calculated by RELAP/SCDAPSIM code. The architecture of the developed code is presented. The implementation of multi-variant calculation for problem solution and graphical interface are described. The results of the software are shown. The algorithm takes into account the uncertainty of input parameters, errors of the empirical correlations and errors of the calculation models.
The software allows to get a realistic assessments of the major criteria for fuel rod parameters in the accidents of LOCA type, for example, the peak cladding temperature and the equivalent cladding reacted etc. with estimates of their uncertainties as borders of a confidence interval with a specified safety level.