Investigation of Radioisotopes Produced in the Core of a Navy Nuclear Reactor with Low- and High-Enriched Uranium Flues During One Cycle

Abstract

ABSTRACT Today, nuclear reactors, especially small reactors, have been significantly welcomed in different countries and have various applications, including use as desalination plants, naval propulsions, etc. During the operation of the reactor, different types of radioisotopes are produced, some of which have very high activity and half-life. The type and amount of radioisotopes produced depends on the type of fuel used, the level of enrichment and the operating time of the reactor. The atomic density and activity of the most important radioisotopes for a typical reactor with two types of high and low enrichment fuel have been calculated in terms of time using MCNPX and CINDER codes. The activity of some of these radioisotopes is high and it is necessary to pay attention to possible environmental hazards. In this research, using the MCNPX Monte Carlo code, the core of a small nuclear reactor proposed as a Virginia class submarine propulsion with a power of 150 MWth was modeled. Using the BURN and KCODE cards in this code as well as the CINDER code, the fuel burnup calculations of the core of this naval reactor have been performed. For this reactor, there are two types of metal alloy fuels, including the high-enrichment UO2-Zr fuel and the low-enrichment U-10Mo fuel, and fuel burnup calculations have been performed for both fuels. After calculations, different types of radioisotopes were identified and changes in atomic density and activity quantities were calculated for the most important of these radioisotopes with high half-life during cycle and compared.