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NKS Programme Area: | NKS-R | Research Area: | Reactor physics | Report Number: | NKS-413 | Report Title: | Development of a hybrid neutron transport solver in 2 energy groups – final report | Activity Acronym: | HYBRID | Authors: | Huaiqian Yi, Christophe Deamzière, Paolo Vinai, Jaakko Leppänen, | Abstract: | This project investigates the feasibility of performing reactor physics calculations for nuclear cores using a hybrid neutron transport methodology, by combining deterministic and probabilistic modelling techniques. In the presented implementation, a deterministic response matrix method was developed in Matlab. The necessary probabilities appearing in the response matrix method were estimated in advance using a probabilistic solver – the Monte Carlo code Serpent2. Ultimately, the hybrid framework will combine the advantages of the deterministic approach (fast running calculations) with the ones of the probabilistic approach (high flexibility in modelling any geometry and high accuracy). In the response matrix method, two grids are used: one fine grid for estimating the scalar neutron flux and a coarse grid for computing the neutron currents on this grid. In this second phase of the project, the framework was verified and new procedures to estimate the required probabilities were developed. Several two-dimensional test cases were then developed for benchmarking the computation of such probabilities and for benchmarking the response matrix framework itself. Compared to the earlier phase of the project, the framework now provides very good results, with a deviation of the dominant eigenvalue smaller than typically 50 pcm. Concerning the spatial distribution of the flux, some acceptable agreement was also obtained, with relative deviations generally smaller than 5%. In some cases, though, higher discrepancies were noticed. Additional investigations are necessary to identify the root cause of the larger observed deviations in such cases, in order to further increase the fidelity of the simulations. | Keywords: | nuclear reactor calculations, neutron transport, deterministic methods, probabilistic methods, hybrid methods | Publication date: | 04 Dec 2018 | ISBN: | ISBN 978-87-7893-502-1 | Number of downloads: | 1510 | Download: | NKS-413.pdf |
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