Neutronic study of UO2-BeO fuel with various claddings

Abstract

The neutronic properties of UO2-BeO fuel with various claddings are investigated through the Monte Carlo methods and the Linear Reactivity Model. A second order polynomial function is suggested to describe the relationship between the difference of the reactivity at the End of Cycle and the two factors, the uranium enrichment and the volume content of BeO in the UO2-BeO fuel. The uranium enrichment is determined to ensure the cycle length for each BeO fraction with the zircaloy, FeCrAl, and SiC claddings. Similar neutronic properties are observed between the zircaloy and SiC claddings for a given BeO fraction, including the infinity multiplication factor, the gas release, the power distribution, and the isotopic concentrations. An important feature of the UO2-BeO fuel is the production of 4 He, which is significant compared with the current UO2 fuel. Less production rates of xenon and krypton are found in the case of UO2-BeO-FeCrAl fuel-cladding system, while those in the UO2-BeO-zircaloy and UO2-BeO-SiC systems are quite similar to the current UO2-zircaloy system. The power distribution in an assembly or in a fuel pellet is flatter for the higher BeO fraction with the same cladding. Higher peak power in a fuel assembly is found with the FeCrAl cladding than that with the other two claddings, while the radial power distribution is quite similar for the three claddings.

Hydroxylherderite (Ca2Be2P2O8(OH)2) stability under extreme conditions (up to 750°C/100 GPa)

“…Besides, BeO, as a member of ceramic materials, also has high radiation, chemical, and temperature stability 2,3 . As a consequence, a number of BeO studies under different extreme conditions were performed 4–7 . For these reasons, Be is on the “strategic and critical materials” list of the US Department of Defense and of the European Union 8…”

“…2,3 As a consequence, a number of BeO studies under different extreme conditions were performed. [4][5][6][7] For these reasons, Be is on the "strategic and critical materials" list of the US Department of Defense and of the European Union. 8 Beryllium minerals are of interest both for Earth sciences and for material applications.…”

BeO Utilization in Reactors for the Improvement of Extreme Reactor Environments - A Review

“…The composite fuel has a large (n,α) cross-section in the neutron's different energy spectrum. The zircaloy alloy cladding and SiC cladding have similar infinite multiplication factors k inf , also at low burnup, the k inf of SiC claddings act a little bit higher (Chen and Yuan, 2020). The SiC has lower neutron absorption cross-sections, while the FeCrAl claddings have a larger thermal neutron absorption cross-section, inducing a lower k inf .…”

“…Then Snead (2005) reviewed the utilization of BeO in space reactors. Chen and Yuan (2020) studied the neutronics of the UO 2 -BeO fuel with various claddings. It can be seen that the research on the BeO material has always been ongoing for its applications in the nuclear industry.…”