Study of the optimal model and parameters of the Th–U cycle nuclei

Recent developments in the advanced reactor concept have renewed interest in the Th–U fuel cycle. This interest stems from its potential advantages over the traditional U–Pu fuel cycle, particularly in mitigating the major health concerns associated with long-lived nuclear waste. Unfortunately, thorium fuel has been suffering from the quality of nuclear data for the relevant isotopes as a result of inadequate attention previously given to the thorium fuel cycle. In some cases, the nuclear reaction data uncertainties are larger than the target accuracies required by the nuclear plant designer. This study provides an improved and accurate cross-section of 232 Th, 231,232 Pa, and 233,235 U, which play vital roles in the 232 Th– 233 U fuel cycles. Statistical modeling code (EMPIRE 3.2.3) was used with a combination of phenomenological models to obtain cross-sections to fit the available experimental data and the existing evaluated library. If reliable predictions of the reaction cross-sections are to be realized, the fission cross-section at lower energies remains a region for improvement. However, the cross-sections were predicted at a lower energy, where the experiments are difficult to conduct. This supports the need for an improved cross-section of isotopes that are relevant to the Th–U fuel cycle.