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2025 ANS Annual Conference
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High-temperature plumbing and advanced reactors
The use of nuclear fission power and its role in impacting climate change is hotly debated. Fission advocates argue that short-term solutions would involve the rapid deployment of Gen III+ nuclear reactors, like Vogtle-3 and -4, while long-term climate change impact would rely on the creation and implementation of Gen IV reactors, “inherently safe” reactors that use passive laws of physics and chemistry rather than active controls such as valves and pumps to operate safely. While Gen IV reactors vary in many ways, one thing unites nearly all of them: the use of exotic, high-temperature coolants. These fluids, like molten salts and liquid metals, can enable reactor engineers to design much safer nuclear reactors—ultimately because the boiling point of each fluid is extremely high. Fluids that remain liquid over large temperature ranges can provide good heat transfer through many demanding conditions, all with minimal pressurization. Although the most apparent use for these fluids is advanced fission power, they have the potential to be applied to other power generation sources such as fusion, thermal storage, solar, or high-temperature process heat.1–3
Mohammad Abdul Motalab, Woosong Kim, Yonghee Kim
Nuclear Technology | Volume 201 | Number 2 | February 2018 | Pages 122-137
Technical Paper | doi.org/10.1080/00295450.2017.1414541
Articles are hosted by Taylor and Francis Online.
This paper reports on the improvement of the power coefficient of reactivity (PCR) and minimization of the coolant void reactivity (CVR) of a CANDU6 reactor. A burnable absorber of Er2O3 (erbia) was mixed homogeneously with UO2 fuel in the central fuel element to maximize the Doppler broadening and minimize the CVR of the CANDU6 reactor. In this study, recovered uranium (RU) with 0.9 wt% 235U enrichment was utilized in the advanced CANFLEX fuel bundle instead of natural uranium (NU). First, the optimal loading of erbia was investigated through lattice-based analysis, and its impact on the lattice characteristics was examined. In particular, both the fuel Doppler effect and CVR were evaluated for the RU-loaded lattice. For a more reliable analysis, a three-dimensional (3-D) equilibrium core was determined based on the standard time-average methods for erbia-loaded CANDU6 cores using the Serpent-COREDAX/CANDU code system. The core analysis was based on a hybrid two-step method in which the lattice analysis was performed by the Serpent Monte Carlo code, and the 3-D whole-core analysis was done using a diffusion theory–based nodal code named COREDAX. For the derived equilibrium cores, the core performances were evaluated in terms of the fuel burnup and power profile. Additionally, the safety parameters, including the PCR and CVR, were evaluated for the equilibrium core conditions. The safety parameters of the 3-D whole core were compared with those obtained with simple lattice-based analysis. It was observed in the analysis that Er-loaded CANFLEX-RU fuel provides a 60% more negative fuel temperature coefficient than standard CANDU-NU fuel.