Sensitivity and uncertainty analyses for a fast molten salt reactor

This study aims to investigate the effect of feedback parameters on the effective multiplication factor (k-eff) value in the MSFR (Molten Salt Fast Reactor) system using different fuel types with varying compositions, to examine the effects of feedback parameters on k-eff, and to calculate the cumulative contribution of these parameters to uncertainty. The lack of comprehensive studies on sensitivity and uncertainty analysis for MSFR in the literature is a strong motivation. Using the SCALE 6.2 (Standardized Computer Analyses for License Evaluation) code, which is an advanced code system for neutronic analyses, to obtain sensitivity and uncertainty analysis results and thereby contribute to the literature. The TSUNAMI-3D (Tools for Sensitivity and Uncertainty Analysis Methodology Implementation) module within the SCALE code is used in the sensitivity and uncertainty analysis. After defining the information about the nuclear reactor system to be analyzed in the relevant module (composition values, geometric details), the energy-dependent cross-section library and SAMS (Sensitivity Analysis Module for SCALE) code lines are added. After activating the simulation, sensitivity coefficients and uncertainty measurement values are obtained. As a result of this study, it is observed that for all fuels used, the (nubar) value and (fission) reactions are dominant in positive sensitivity coefficients, while (n,gamma) reactions are dominant in negative sensitivity coefficients. Furthermore, in terms of percentage uncertainty for the 7 fuel types, it was determined that the type of fissile material and composition differences in the fuel are critical in uncertainty measurement. The original value of this study is that, in addition to the sensitivity and uncertainty analysis for the 7 fuel compositions available in the literature, analyses were performed for natural and enriched states of Li-Cl salts in fuel types located at subcritical and supercritical keff values placed in the MSFR design geometry. It was determined that enriched Cl is a good alternative because it shows a significant increase in keff value for both criticality values and reduces the uncertainty percentage. In addition, when uncertainty measurements were performed for all fuels, the 252-group nuclear data library was found to be the most reliable library.