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Truchet, G.*; Van Rooijen, W. F. G.*; Shimazu, Yoichiro*; Yamaguchi, Katsuhisa
Annals of Nuclear Energy, 51, p.94 - 106, 2013/01
Times Cited Count：6 Percentile：44.02(Nuclear Science & Technology)The Modified Neutron Source Method (MNSM) is applied to the prototype FBR Monju. Among Monju's particularities that have a big influence on the MNSM factors are: the presence of two californium sources near the core and the position of the detector, which is located far from the core outside of the reactor vessel. In order to evaluate the detector count rate, a propagation calculation has been conducted from the reactor vessel to the external detector. For two subcritical states, an estimation of the reactivity has been made and compared to experimental data obtained in the restart experiments at Monju (2010). Results indicate a good agreement between the MNSM reactivity and the reactivity measured with other methods.
Van Rooijen, W. F. G.*; Chiba, Go
Annals of Nuclear Energy, 38(1), p.133 - 144, 2011/01
Times Cited Count：15 Percentile：73.97(Nuclear Science & Technology)The present work discusses the calculation of the diffusion coefficient of a lattice of hexagonal cells, with both "sodium present" and "sodium absent" conditions. Calculations are performed in the framework of lattice theory. Unlike the classical approaches, our heterogeneous leakage model allows the calculation of diffusion coefficients under all conditions, even if planar voids are present in the lattice. Equations resulting from this model are solved using the method of characteristics (MOC). Independent confirmation of the MOC result comes from Monte Carlo calculations, in which the diffusion coefficient is obtained without any of the assumptions of lattice theory. It is shown by comparison to the Monte Carlo results that the MOC solution yields correct values of the diffusion coefficient under all conditions, even in cases where the classic calculation of the diffusion coefficient fails.
Van Rooijen, W. F. G.*; Hazama, Taira; Takeda, Toshikazu*
Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 14 Pages, 2010/10
For the reactor physics analysis of fast critical assemblies as well as LMFBRs, the diffusion coefficient is one of the required pieces of data. In the present analysis, the diffusion coefficient is determined using the Benoist-formalism, which is based on directional collision probabilities. For LMFBR analysis including void regions, the Benoist-formalism breaks down if two-dimensional (slab or slab-like) void regions are present. Furthermore, the Benoist-style assumption of zero buckling is questionable in fast reactors. Research is being done to identify improved cell calculations, in order to calculate the diffusion coefficient in one- and two-dimensional unit cells containing real void regions.
Chiba, Go; Van Rooijen, W. F. G.*
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Anisotropic diffusion coefficients for voided hexagonal lattices, which cannot be obtained using the classical benoist formalism, are successfully calculated with the method of characteristics. The proposed method is free from the divergence problem, and results in more rigorous diffusion coefficients based on the leakage theory.
Chiba, Go; Van Rooijen, W. F. G.*
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A property of a lattice composed of asymmetric unit cells is investigated. It is shown that usual deterministic calculation procedure based on the unit cell homogenization works well even if the unit cell is asymmetric by considering a direction dependence of homogenized total cross sections.
Yamaguchi, Katsuhisa; Truchet, G.*; Van Rooijen, W. F. G.*; Shimazu, Yoichiro*
no journal, ,
Konomura, Mamoru; Tamagno, P.*; Takeda, Toshikazu*; Van Rooijen, W. F. G.*
no journal, ,
Konomura, Mamoru; Tamagno, P.*; Van Rooijen, W. F. G.*; Takeda, Toshikazu*
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