کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6929928 | 867531 | 2016 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Stability of Monte Carlo k-eigenvalue simulations with CMFD feedback
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی کامپیوتر
نرم افزارهای علوم کامپیوتر
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
In this paper we perform a Fourier stability analysis of MC-CMFD, a hybrid Monte Carlo k-eigenvalue method that utilizes coarse mesh finite difference (CMFD) feedback. The MC-CMFD method is nonlinear and contains random statistical errors; both of these features are inconsistent with the direct application of a Fourier stability analysis. To accomplish this analysis, we first formulate a non-random iteration method that approximates MC-CMFD, by assuming an infinite number of Monte Carlo particles per cycle. Then we (i) linearize this method, and (ii) Fourier-analyze the linearized method to theoretically predict its convergence properties. Finally, we demonstrate by direct numerical simulations that the Fourier analysis of the linearized non-random method accurately predicts the stability and fission source convergence rate (during the inactive cycles) of the original nonlinear MC-CMFD method. We do this by comparing the predictions of the Fourier analysis to simulations that utilize (i) a high-fidelity SN-CMFD code (which has no random statistical errors), and (ii) a MC-CMFD code (which has random statistical errors). The Fourier analysis and our two test codes confirm that the MC-CMFD method is stable if the optical thickness of the coarse grid (in the low-order CMFD calculation) is sufficiently small. However, the spectral radius increases monotonically with the coarse grid size, and if the latter exceeds a critical value, the MC-CMFD method becomes unstable. We discuss some implications of our results for practical MC-CMFD simulations.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Computational Physics - Volume 321, 15 September 2016, Pages 947-964
Journal: Journal of Computational Physics - Volume 321, 15 September 2016, Pages 947-964
نویسندگان
Kendra P. Keady, Edward W. Larsen,