AFEN-polynomial nodal method for burnup gradient correction
- Korea Advanced Inst. of Science and Technology, Taejon (Korea, Democratic People`s Republic of)
In general, neglecting the large intranodal cross-section gradients induced by depletion and feedback causes a nodal method to lose its accuracy in predicting nodal unknowns acceptably. Recently, in context of the analytic function expansion nodal (AFEN) method, Noh and Cho developed a rehomogenization burnup correction model that homogenizes the burnt fuel assembly using equivalence theory. They expanded the fluxes of a burnt fuel assembly in terms of quartic polynomial functions with nonzero current boundary conditions obtained from previous feedback iterations. The fluxes arc used to get additional flux-volume-weighted cross sections and discontinuity factors of the assembly. In this paper, we develop an AFEN-polynomial correction model that directly solves the nodal diffusion equation with spatially varying cross sections due to burnup gradient. In this model, we retain the original analytic basis functions that are derived from the diffusion equation containing only volume-averaged cross sections (burnup dependent), and we add second-order polynomial correction terms in the expansion. Because this model solves the whole core problem without any assumption of nodal quantity and rehomogenization, its accuracy is not affected by the previous feedback calculation.
- OSTI ID:
- 436989
- Report Number(s):
- CONF-9606116-; ISSN 0003-018X; TRN: 96:005275-0228
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 74; Conference: Annual meeting of the American Nuclear Society (ANS), Reno, NV (United States), 16-20 Jun 1996; Other Information: PBD: 1996
- Country of Publication:
- United States
- Language:
- English
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