Single neutron tracking method for calculating the probability of survival based on the RMC code

Abstract

In a weak neutron source system, the neutron chains rarely overlap, and hence the neutrons should be described by stochastic kinetics. The probability of survival (POS) is a quantity that is often calculated in the field of stochastic kinetics and is also a simple index to test the correctness of the method of describing weak source systems. The general Monte Carlo method for calculating POS needs to control the number of simulated particles, which introduces deviations. In this work, an innovative single neutron tracking method for calculating POS based on the Reactor Monte Carlo (RMC) code is proposed, and it does not need to control the number of particles. The relative difference between the POS calculated by RMC and those calculated by MCATK are less than 6%. The new method is more accurate and user-friendly than the traditional method.