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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
W. O. Doggett, Fred A. Bryan, Jr.
Nuclear Science and Engineering | Volume 39 | Number 1 | January 1970 | Pages 92-104
Technical Paper | doi.org/10.13182/NSE70-1
Articles are hosted by Taylor and Francis Online.
Berger et al. of the National Bureau of Standards have utilized the Monte Carlo method to calculate total scatter differential dose transmission and reflection coefficients for plane unidirectional gamma rays incident on concrete barriers of finite thickness. These calculations were performed for source energies of 0.2, 0.4, 0.66, 1.25, 5.0, and 10.0 MeV with incident obliquity angles cos θ0 = 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01; emergent obliquity angles cos θd = 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01; emergent azimuthal angles relative to the ongoing incident ray = 0, 30, 60, 90, 120, 150, and 180 degrees; and slab thicknesses of 0.25, 0.5, 0.75, 1, 2, 3, and 4 mean-free-paths. These data are used herein to compute dose rate slant penetration and reflection probabilities for a detector located adjacent to a barrier. The total scatter contribution was calculated by numerically integrating the Monte Carlo data of Berger et al. over the 2π solid angle subtended by the barrier relative to the detector location. In addition to results for the above listed thicknesses, energies, and incident obliquities, slant penetration and reflection probabilities are computed for the 1.12 h unfractionated fission spectrum by interpolating and weighting the Monte Carlo data at appropriate energies and thicknesses. The probabilities obtained herein compare favorably with those obtained by the Spencer-Fano moments method for an infinite medium, with other Monte Carlo studies, and with experimental data.