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First Collision Source in the IDT Discrete Ordinates Transport Code


The first collision source calculation has recently been implemented in the IDT discrete ordinates nodal and short characteristics transport code. Several methods are developed and compared with the multigroup discrete ordinates transport code PARTISN and the continuous in energy Monte Carlo code TRIPOLI4 R. The paper describes five different options: 1) a non-conservative scheme based on the tracking through the mesh centers, 2) a non-conservative averaging of mesh corner values, 3) cell based balance scheme with the surface averaged interface currents, 4) semi-analytic approach based on a conservative local-cell balance with numerical surface integration and 5) method of characteristics (MOC) based conservative scheme. The comparisons are performed on simple one group 3D test cases, one with a simple homogeneous geometry and another with very strong material heterogeneities. The detector responses are obtained for a 42-group 3D gamma shielding problem and compared. Results show that among the different options, the most robust are MOC, Mesh Center and Corner Average since they are positive, whereas schemes based on the Cell Balance may incur in negative solutions due to an inaccurate estimation of boundary currents. However, both Mesh Center and Corner Average have slow spatial convergence and may undergo conservation issues for coarse meshes. The MOC scheme, on the contrary, preserves global balance.
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Dates and versions

cea-02510285 , version 1 (17-03-2020)


  • HAL Id : cea-02510285 , version 1


Igor Zmijarevic, Daniele Sciannandrone. First Collision Source in the IDT Discrete Ordinates Transport Code. MandC 2017, 2017, Jeju, Japan. ⟨cea-02510285⟩


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