Thermochemically-informed mass transport model for interdiffusion of U and Zr in irradiated U-Pu-Zr fuel with fission products

Thermodynamically Informed Nuclear Fuel Codes—A Review and Perspectives

“…Figure 4 illustrates the predicted distribution of U and Zr in fresh U-Pu-Zr fuel and irradiated U-Pu-Zr with comparison to post-irradiation examination measurements from Kim et al [44]. Clearly, the effects of fuel irradiation have a considerable impact on U and Zr interdiffusion calculations [43]. In both cases, the typical 'bathtub' profile in Zr content is observed and the simulation results from the irradiated case is closer to that of the Post Irradiation Examination (PIE) results from Kim et al [44] than was the case for fresh fuel.…”

“…Poschmann et al [43] further extended the BISON-THERMOCHIMICA work from Simunovic et al [40] on irradiated UO 2 oxide fuel to irradiated U-Pu-Zr metallic fuel. One principle distinction in the latter campaign is that both U and Zr were simulated to interdiffuse [43], whereas only oxygen was simulated to diffuse in the former case [40].…”

“…Poschmann et al [43] further extended the BISON-THERMOCHIMICA work from Simunovic et al [40] on irradiated UO 2 oxide fuel to irradiated U-Pu-Zr metallic fuel. One principle distinction in the latter campaign is that both U and Zr were simulated to interdiffuse [43], whereas only oxygen was simulated to diffuse in the former case [40]. Furthermore, metallic fuel appears to experience significant phase transformations under normal operating conditions, whereby an orthorhombic alpha phase is stable at low temperatures while a body centred cubic gamma phase is predominant at higher temperatures [43].…”

“…One principle distinction in the latter campaign is that both U and Zr were simulated to interdiffuse [43], whereas only oxygen was simulated to diffuse in the former case [40]. Furthermore, metallic fuel appears to experience significant phase transformations under normal operating conditions, whereby an orthorhombic alpha phase is stable at low temperatures while a body centred cubic gamma phase is predominant at higher temperatures [43]. Due to these marked transformations in U and Zr bearing phases, the transport properties of both U and Zr were made phase dependent (i.e., D 0 and Q); however, not all of those transport properties were well known or known at all [43].…”

“…Figure 4. The predicted distribution of Zr is plotted when assuming fresh U-Pu-Zr fuel and irradiated fuel according to Poschmann et al[43] with comparisons made to post-irradiation examination experiments from Kim et al[44].…”