Development and acceleration of a 3D characteristics method including an axial polynomial expansion of cross sections
Description
This thesis introduces a polynomial expansion for the axial profiles of macroscopic cross sections in TDT, the 3D Method Of Characteristics (MOC) solver of the APOLLO3R code, with the aim to apply this higher-order scheme to depleted systems. The polynomial description allows for a proper representation of the cross sections axial gradients, which appear as the burnup increases, while using a coarser axial mesh than that required by the traditional Step-Constant (SC) approximation. The MOC equations and the DPN synthetic acceleration have been adapted to the new hypotheses and a specific strategy has been developed to allow TDT to interface with the self-shielding module and the depletion solver. The method has been applied to different pressurized water reactors sub-systems, comparing the results with those of the SC approach: the depletion study has shown the decisive advantage of the polynomial method in terms of memory and computing time. (author)
Abstract (French)
Cette these introduit un developpement polynomial pour les profils axiaux de sections e caces macroscopiques dans le solveur TDT du code APOLLO3R, utilisant la methode des caracteristiques (MOC) en 3D, dans le but d'appliquer ce schema d'ordre superieur aux systemes en evolution. La description polynomiale permet une representation appropriee des gradients axiaux des sections e caces, qui apparaissent a mesure que le burnup augmente, tout en utilisant un maillage axial plus grossier que celui requis par l'approximation traditionnelle Step-Constant (SC). Les equations du MOC et l'acceleration synthetique DPN ont ete adaptees aux nouvelles hypotheses et une strategie specifique a ete developpee pour permettre a TDT de s'interfacer avec le module d'autoprotection et le solveur de depletion. La methode a ete appliquee a differents sous-systemes de reacteurs a eau pressurisee, en comparant les resultats avec ceux de l'approche SC: l'etude de l'evolution a montre l'avantage decisif de la methode polynomiale en termes de memoire et de temps de calcul
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Additional details
Additional titles
- Original title (English)
- Developpement et acceleration d'une methode des caracteristiques 3D incluant une expansion axiale polynomiale des sections efficaces
Publishing Information
- Imprint Pagination
- 135 p.
- Report number
- FRCEA-TH--14850
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 54007455
- Subject category
- S73: NUCLEAR PHYSICS AND RADIATION PHYSICS;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- A CODES; APPROXIMATIONS; BOUNDARY CONDITIONS; BURNUP; COMPUTERIZED SIMULATION; CROSS SECTIONS; EIGENVALUES; NEUTRON TRANSPORT THEORY
- Descriptors DEC
- CALCULATION METHODS; COMPUTER CODES; SIMULATION; TRANSPORT THEORY
Optional Information
- Notes
- 69 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses