Transuranus versus Helios: Computation of Selected Nuclides in Burnt–up Nuclear Fuel

In 2004, as many as 444 nuclear energy reactors were operated in 31 countries worldwide. Most of them burn classical nuclear fuels, thus either uranium dioxide UO2 containing natural uranium, uranium enriched by U-235 or, less often, the so-called MOX (Mixed Oxide) fuel, which is a mixture of UO2 and PuO2 . The use of nuclear fuels and introduction of their novel types requires detailed knowledge of the behaviour of the fuels in all possible states in which they occur. However, experimental studies and verifications of the behaviour of nuclear fuels often cannot be performed because of safety and instrumental reasons or because of too long times needed to conduct such studies. This is why modelling and computer simulation of the behaviour of nuclear fuels are increasingly used. Computer analyses and simulations allow obtaining the evolutions of single characteristics of the fuel at any instant in the course of its burn-up. Naturally, the knowledge of the properties of the nuclear fuel not only improves the efficiency but also the operation safety. Numerous computer codes have been developed for nuclear fuel burn-up modelling and simulation. Nevertheless, they usually focus on different aspects and properties of the fuel. The objective of this paper is to employ the codes HELIOS and TRANSURANUS to simulate the properties of UO2 and MOX during the burn-up and to compare the obtained results.