Monte Carlo Modelling of Loosely Coupled Fissionable Systems

In the paper we describe problems related to the convergence diagnostics in the Monte Carlo modeling of the loosely coupled fissionable systems like arrays of the spent fuel elements. The logistics and trans-portation of the spent nuclear fuel is a complex process due to its high radioactivity and thus contamination risk for the biosphere and human beings. The detection of convergence is important for the accurate estimation of system multiplication factor and associated standard deviation. The multiplication factor is the main safety parameter used for design and optimization of the equipment for spent fuel handling and transportation in order to fulfill the international safety and security standards.