The isotopic fractions of plutonium produced in a reactor are of significant value as nuclear forensic signatures, and the mechanisms of their production and alteration should be investigated thoroughly. A series of neutronics calculations were made on a typical UO₂ PWR setup, introducing (Th, U)O₂ MOX rods gradually, to investigate how the presence of Th affects the ²⁴⁰Pu/²³⁹Pu and ²⁴²Pu/²³⁹Pu ratios in the remaining UO₂ fuel rods. A relationship is found that links the percentage change in these ratios, with the burnup and Th content in the configuration. In an extreme case, it was found that the presence of Th may increase the ratio of ²⁴²Pu/²³⁹Pu by as much as 3.5% at low burnup.

反应堆中产生的p的同位素分数作为核法证标记具有重要价值，应彻底研究其产生和改变的机理。在典型的UO ₂ PWR装置上进行了一系列中子学计算，逐步引入了（Th，U）O ₂ MOX棒，以研究Th的存在如何影响硅橡胶中²⁴⁰ Pu / ²³⁹ Pu和²⁴² Pu / ²³⁹ Pu的比率。剩余的UO ₂燃料棒。发现一种关系，这些关系将这些比率的百分比变化与配置中的燃耗和Th含量联系起来。在极端情况下，发现Th的存在可能会增加²⁴²的比例Pu / ²³⁹ Pu在低燃耗时高达3.5％。