Abstract
The subgroup method currently implemented in the APOLLO3® lattice code relies on moment-based probability tables, also called mathematical probability tables. This paper details the on-the-fly construction of another kind of probability tables, known as physical probability tables, by conserving self-shielded cross sections over a range of dilutions with two different methods. The first is an already existing method in other lattice codes and consists of approximating the cross section with a Padé approximant, whose coefficients are determined with a linear system. The second method is an improvement of the first and relies on the use of orthogonal polynomials in order to get a linear system as diagonal as possible. The two methods are compared in this paper, their numerical errors and the possible improvements are highlighted.
| Original language | English |
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| Title of host publication | Proceedings of the International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2021 |
| Publisher | American Nuclear Society |
| Pages | 1992-2001 |
| Number of pages | 10 |
| ISBN (Electronic) | 9781713886310 |
| DOIs | |
| State | Published - 2021 |
| Externally published | Yes |
| Event | 2021 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2021 - Virtual, Online Duration: Oct 3 2021 → Oct 7 2021 |
Publication series
| Name | Proceedings of the International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2021 |
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Conference
| Conference | 2021 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering, M and C 2021 |
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| City | Virtual, Online |
| Period | 10/3/21 → 10/7/21 |
Funding
The authors wish to express their appreciation and gratitude to Dr. Richard Sanchez for many fruitful discussions. APOLLO3® is a registered trademark of CEA. We gratefully acknowledge EDF and Framatome for their long term partnership and their support.
Keywords
- Physical probability table
- Self-shielding
- Subgroup method