Recent Advances in Perturbative Methods Applied to Nuclear Engineering Problems

This paper describes the main perturbative methods used in sensitivity analysis. It also presents several applications to calculate sensitivity coefficients of interest to nuclear engineering problems. These topics will cover only the papers presented in the 10th Brazilian Meeting on Reactor Physics and Thermal Hydraulics - X ENFIR. First the matrix formalism of the perturbation theory is applied in a simplified model to study the hot channel of PWR reactors. Comparisons between perturbative and direct calculations show good agreement, which demonstrates that the matrix formalism is an important tool for discretized system analysis. A second application of the GPT methodology to a reliability engineering problem of great practical interest follows: that of the analysis of the influence of the demand rate on the reliability of a process plant equipped with a single protective channel. The application of the GPT approach needs the solution of the system for a few points (reference solutions). The results agree very well with those published in the literature. In a third application, the so called differential method was applied to the sensitivity analysis of the waterhammer effect in hydraulic networks. As a fourth application, the GPT formalism is used to analyze the sensitivity of some responses of interest to boron neutron capture therapy. Attention is focused on diffusive source-driven systems. Finally a methodology is described relevant to the use of data from experimental facilities with respect to a reference design.