A Two-Dimensional Intranodal Flux Expansion Method for Hexagonal Geometry

Grundmann, U.; Hollstein, F.

doi:10.13182/nse99-a2082

Cited by 21 publications

(5 citation statements)

References 5 publications

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“…It solves two-group diffusion equations by nodal method. To find neutron flux distribution inside the nodes, two different approximations are used in DYN3D [3]. The first one is HEXNEM1 method in which the nodes are coupled only by the averaged fluxes and currents at the hexagon sides.…”

Section: Results Of Calculationsmentioning

confidence: 99%

Validation of Pin Power Calculations Using DYN3D on MIDICORE Benchmark

Kuchyn

Ovdiienko

Khalimonchuk

et al. 2019

Nucl. and Rad. Safe.

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Three-dimensional code DYN3D is widely used for the calculation of steady states and transients in light water reactors with hexagonal fuel assemblies like VVER. The capability of pin-by-pin power calculation is implemented in the code through an intranodal power reconstruction approach. The calculations of pin power distribution using DYN3D were performed for AER MIDICORE benchmark for the validation of given extension and developed cross-section library. MIDICORE VVER-1000 core periphery power distribution benchmark was proposed on the 20th Symposium of AER. It is a 2D calculation benchmark based on the VVER-1000 core cold state geometry taking into account the geometry of explicit radial reflector. The main issue of MIDICORE benchmark is to provide the reference solution for the validation of pin-by-pin power distribution at the VVER-1000 core periphery calculated by few-group diffusion codes. Various 3D neutron kinetics nodal solvers HEXNEM1, HEXNEM2 and HEXNEM3 are used in DYN3D for neutron flux distribution calculation. The AER MIDICORE benchmark was solved using all solvers implemented in DYN3D with regard to the three most representative fuel assemblies. Considered fuel assemblies are placed both in the inner part and in the peripheral part of the core, and contain the pin with integrated gadolinium burnable absorber. This paper provides results of comparing the effective multiplication factor, assembly-wise power distribution and pin-by-pin power distribution calculated by DYN3D with benchmark data.

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Section: Results Of Calculationsmentioning

confidence: 99%

Validation of Pin Power Calculations Using DYN3D on MIDICORE Benchmark

Kuchyn

Ovdiienko

Khalimonchuk

et al. 2019

Nucl. and Rad. Safe.

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“…Two results are provided for each single case, one using six neutronic nodes per fuel assembly and another using 24 neutronic nodes per fuel assembly. A comparison is performed using the average of the results given by PARCS (Downar et al, 2004) and DYN3D (Grundmann and Hollstein, 1999) codes as reference solution.…”

Section: Verification Resultsmentioning

confidence: 99%

“…However, in this approach, the number of continuity conditions (and thus the number of unknowns) at the nodal boundaries needed to obtain the required accuracy, increases the computing time, specially in 3D hexagonal geometry. A variation of the previous method is the HEXagonal Nodal Expansión Method (HEXNEM2) implemented in the DYN3D code (Grundmann and Hollstein, 1999). It is based on a twodimensional expansión of the intranodal fluxes in the hexagon using both 2nd order polynomials and exponential functions.…”

Section: Introductionmentioning

confidence: 99%

Extension of the analytic nodal diffusion solver ANDES to triangular-Z geometry and coupling with COBRA-IIIc for hexagonal core analysis

Lozano¹,

Jiménez²,

García-Herranz³

et al. 2010

Annals of Nuclear Energy

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In this paper the extensión of the multigroup nodal diffusion code ANDES, based on the Analytic Coarse Mesh Finite Difference (ACMFD) method, from Cartesian to hexagonal geometry is presented, as well as its coupling with the thermal-hydraulic (TH) code COBRA-IIIc for hexagonal core analysis.In extending the ACMFD method to hexagonal assemblies, triangular-Z nodes are used. In the radial plañe, a direct transverse integration procedure is applied along the three directions that are orthogonal to the triangle interfaces. The triangular nodalization avoids the singularities, that appear when applying transverse integration to hexagonal nodes, and allows the advantage of the mesh subdivisión capabilities implicit within that geometry. As for the thermal-hydraulics, the extensión of the coupling scheme to hexagonal geometry has been performed with the capability to model the core using either assemblywise channels (hexagonal mesh) or a higher refinement with six channels per fuel assembly (triangular mesh). Achieving this level of TH mesh refinement with COBRA-IIIc code provides a better estimation of the in-core 3D flow distribution, improving the TH core modelling.The neutronics and thermal-hydraulics coupled code, ANDES/COBRA-IIIc, previously verified in Cartesian geometry core analysis, can also be applied now to full three-dimensional VVER core problems, as well as to other thermal and fast hexagonal core designs. Verification results are provided, corresponding to the different cases of the OECD/NEA-NSC VVER-1000 Coolant Transient Benchmarks.

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“…In DYN3D a 2D Hexagonal Nodal Expansion Method (HEXNEM) is used while the flux is expanded into a combination of polynomials up to second order and exponential functions (Grundmann and Hollstein, 1999;Grundmann et al, 2000). PARCS relies on the 2D Triangle-based Polynomial Expansion Nodal (TPEN) method (Downar et al, 2010) where the flux is expanded into polynomials up to third order.…”

Section: Description Of the Deterministic Full Core Simulatorsmentioning

confidence: 99%