Аннотация: 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