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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
Flavio Dante Giust, Peter Grimm, Rakesh Chawla
Nuclear Science and Engineering | Volume 175 | Number 3 | November 2013 | Pages 292-307
Technical Paper | doi.org/10.13182/NSE12-69
Articles are hosted by Taylor and Francis Online.
Total fission rate measurements have been performed on full-size boiling water reactor fuel assemblies of type SVEA-96 Optima2 in the framework of phase III of the light water reactor (LWR)-PROTEUS experimental program at Paul Scherrer Institute. This paper presents comparisons of calculated, nodal reconstructed, pinwise total fission rate distributions with experimental results. Radial comparisons have been performed for the three axial sections of the assembly (96, 92, and 84 fuel pins), while three-dimensional (3-D) effects have been investigated at pellet level for the two transition regions, i.e., the tips of the short (one-third) and long (two-thirds) partial-length rods. The test zone has been modeled using two different code systems: HELIOS/PRESTO-2 and CASMO-5/SIMULATE-5. The former is presently used for core monitoring and design at the Leibstadt Nuclear Power Plant (KKL). The latter represents the most recent generation of codes constituting the widely applied CASMO/SIMULATE system. For representing the PROTEUS test zone boundaries, partial current ratios - derived from a 3-D Monte Carlo (MCNPX) model of the entire reactor - have been applied to the PRESTO-2 and SIMULATE-5 models in the form of two-group and five-group diagonal albedo matrices, respectively. The MCNPX results have also served as a reference high-order transport solution in the calculation-to-experiment (C/E) comparisons.It is shown that the performance of the nodal methodologies in predicting the global distribution of the total fission rate is very satisfactory. Considering the various radial comparisons, the standard deviations of the C/E distributions do not exceed 1.9% for any of the three methodologies - PRESTO-2, SIMULATE-5, and MCNPX. For the 3-D comparisons at pellet level, the corresponding standard deviations are 2.7%, 2.0%, and 2.1%, respectively.
