Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry
The method of characteristics has very strong geometric adaptability and can be used to solve the 3-D whole core problem of high temperature gas-cooled pebble-bed reactor. However, it suffers from the disadvantages of thousands of iterations and slow calculation speed. At present, there have been so...
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| Format: | Article |
| Language: | English |
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Editorial Board of Atomic Energy Science and Technology
2024-03-01
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| Series: | Yuanzineng kexue jishu |
| Subjects: | |
| Online Access: | https://yznkxjs.xml-journal.net/cn/article/doi/10.7538/yzk.2023.youxian.0358 |
| _version_ | 1797262561708605440 |
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| author | GUO Jian1, GUO Jiong2, LI Fu2, YAN Rui1, ZOU Yang1 |
| author_facet | GUO Jian1, GUO Jiong2, LI Fu2, YAN Rui1, ZOU Yang1 |
| author_sort | GUO Jian1, GUO Jiong2, LI Fu2, YAN Rui1, ZOU Yang1 |
| collection | DOAJ |
| description | The method of characteristics has very strong geometric adaptability and can be used to solve the 3-D whole core problem of high temperature gas-cooled pebble-bed reactor. However, it suffers from the disadvantages of thousands of iterations and slow calculation speed. At present, there have been some attempts to reduce calculation time for method of characteristics, including coarse mesh finite difference (CMFD), general coarse mesh rebalance (GCMR) and general coarse mesh finite difference (GCMFD). The CMFD method is applied to realize the acceleration of regular region like squares. Furthermore, to break through the limitation of macroscopic regular geometry for the numerical acceleration method, researchers successively propose the GCMR method and the GCMFD method, but these methods are very complex to implement in irregular geometries and some approximation factors must be introduced. Based on the analysis of more dense tracks are arranged for the 3-D model, the sparse macro-track transport acceleration method was proposed, which greatly reduces the calculation amount of the acceleration equation and obtains a very good acceleration efficiency without reducing the accuracy. The 2-D method of characteristics divides the angular space into M azimuthal angles and P pole angles. The 3-D method of characteristics generally uses a level symmetric quadrature set. In 2-D geometry, the angle is relatively more dense at the poles. As a result, the 2-D macro-track transport acceleration can select a small number of azimuth angles with reflection symmetry and one pole angle as the solution directions of the acceleration equation. The sparse macro-track transport acceleration method implemented in this paper used the same angles as the method of characteristics. The number of tracks for 3-D problems is an order of magnitude higher than for 2-D problems. That is why reducing the number of 3-D tracks is a promising method for reducing the amount of accelerated equation calculation. This paper applied the macro-track transport acceleration method to 3-D whole core problem of high temperature gas-cooled pebble-bed reactor to solve the problem of irregular geometric numerical acceleration. The sparsity, macro-track length limit, and the maximum iteration step limit of the macro-track method are the main factors that affect the acceleration performance. The selection method of acceleration parameters was studied through two benchmark problems. Excellent speedup ratio can be obtained by setting the sparsity to 3-5, the macro-track length to around 2.0 cm, the acceleration iteration steps limit to 20-60. The results of 3-D small light water reactor benchmark and simplified pebble-bed reactor core model show that about 7 times the time speedup ratio and about corresponding 20 times the iterative step speedup ratio can be achieved. |
| first_indexed | 2024-04-24T23:59:04Z |
| format | Article |
| id | doaj.art-29a5c70ba5a04614900b20ea631604ff |
| institution | Directory Open Access Journal |
| issn | 1000-6931 |
| language | English |
| last_indexed | 2024-04-24T23:59:04Z |
| publishDate | 2024-03-01 |
| publisher | Editorial Board of Atomic Energy Science and Technology |
| record_format | Article |
| series | Yuanzineng kexue jishu |
| spelling | doaj.art-29a5c70ba5a04614900b20ea631604ff2024-03-14T08:34:24ZengEditorial Board of Atomic Energy Science and TechnologyYuanzineng kexue jishu1000-69312024-03-0158365466110.7538/yzk.2023.youxian.0358Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed GeometryGUO Jian1, GUO Jiong2, LI Fu2, YAN Rui1, ZOU Yang101. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; 2. Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084, ChinaThe method of characteristics has very strong geometric adaptability and can be used to solve the 3-D whole core problem of high temperature gas-cooled pebble-bed reactor. However, it suffers from the disadvantages of thousands of iterations and slow calculation speed. At present, there have been some attempts to reduce calculation time for method of characteristics, including coarse mesh finite difference (CMFD), general coarse mesh rebalance (GCMR) and general coarse mesh finite difference (GCMFD). The CMFD method is applied to realize the acceleration of regular region like squares. Furthermore, to break through the limitation of macroscopic regular geometry for the numerical acceleration method, researchers successively propose the GCMR method and the GCMFD method, but these methods are very complex to implement in irregular geometries and some approximation factors must be introduced. Based on the analysis of more dense tracks are arranged for the 3-D model, the sparse macro-track transport acceleration method was proposed, which greatly reduces the calculation amount of the acceleration equation and obtains a very good acceleration efficiency without reducing the accuracy. The 2-D method of characteristics divides the angular space into M azimuthal angles and P pole angles. The 3-D method of characteristics generally uses a level symmetric quadrature set. In 2-D geometry, the angle is relatively more dense at the poles. As a result, the 2-D macro-track transport acceleration can select a small number of azimuth angles with reflection symmetry and one pole angle as the solution directions of the acceleration equation. The sparse macro-track transport acceleration method implemented in this paper used the same angles as the method of characteristics. The number of tracks for 3-D problems is an order of magnitude higher than for 2-D problems. That is why reducing the number of 3-D tracks is a promising method for reducing the amount of accelerated equation calculation. This paper applied the macro-track transport acceleration method to 3-D whole core problem of high temperature gas-cooled pebble-bed reactor to solve the problem of irregular geometric numerical acceleration. The sparsity, macro-track length limit, and the maximum iteration step limit of the macro-track method are the main factors that affect the acceleration performance. The selection method of acceleration parameters was studied through two benchmark problems. Excellent speedup ratio can be obtained by setting the sparsity to 3-5, the macro-track length to around 2.0 cm, the acceleration iteration steps limit to 20-60. The results of 3-D small light water reactor benchmark and simplified pebble-bed reactor core model show that about 7 times the time speedup ratio and about corresponding 20 times the iterative step speedup ratio can be achieved.https://yznkxjs.xml-journal.net/cn/article/doi/10.7538/yzk.2023.youxian.0358high temperature gas-cooled pebble-bed reactormethod of characteristicsmacro-track transport acceleration methodneutron transport |
| spellingShingle | GUO Jian1, GUO Jiong2, LI Fu2, YAN Rui1, ZOU Yang1 Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry Yuanzineng kexue jishu high temperature gas-cooled pebble-bed reactor method of characteristics macro-track transport acceleration method neutron transport |
| title | Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry |
| title_full | Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry |
| title_fullStr | Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry |
| title_full_unstemmed | Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry |
| title_short | Sparse Macro-track Transport Acceleration Method for 3-D Pebble-bed Geometry |
| title_sort | sparse macro track transport acceleration method for 3 d pebble bed geometry |
| topic | high temperature gas-cooled pebble-bed reactor method of characteristics macro-track transport acceleration method neutron transport |
| url | https://yznkxjs.xml-journal.net/cn/article/doi/10.7538/yzk.2023.youxian.0358 |
| work_keys_str_mv | AT guojian1guojiong2lifu2yanrui1zouyang1 sparsemacrotracktransportaccelerationmethodfor3dpebblebedgeometry |