The effect of using above 10% fuels enrichment on neutron energy spectrum and absorption cross sections

One of the most important issues in reactor design is the neutron energy or neutron energy spectrum at the reactor core. nuclear reactors have different fuel enrichment depending on the application. Propulsion reactors are among the reactors that must have lower xenon after shutdown to be able to turn on the reactor for a long time shortly after shutdown. Therefore, determining the correct enrichment of fuel is required to study the effect of increasing enrichment on the energy of neutrons and absorption cross sections.In this paper, while validating WIMS code libraries for use in fuels with a enrichment of more than 10%, the effect of using fuels with a enrichment of more than 10% on the neutron energy spectrum and absorption cross sections, especially the thermal absorption cross section of xenon Has been investigated. The results showed that the increase in enrichment leads to a decrease in the cross-section of ​​Xenon absorption and as a result, a decrease in Xenon peak after shutdown.