蒙特卡罗临界计算全局计数问题新策略研究
|
摘要
基于一个裂变源分布对应香农熵序列的在线收敛性诊断方法,为提高全局计数整体效率的均匀裂变点算法将在首次激活迭代步和首次判断收敛迭代步的最大值之后启动.之后,整体精度指标将每隔固定迭代步数计算一次,一旦达到事先设定的精度标准,整个临界迭代计算将提前终止.这一判断过程将一直持续到事先设定的最大迭代步数为止.通过一个反应堆基准问题C5G7模型的计算表明上述新策略在合适的参数下有助于提高蒙特卡罗临界计算全局计数问题的整体效率.
Traditionally, the Monte Carlo criticality calculation must set a maximum inactive step by experience to ensure that a fission source distribution has converged. The tallying process can only be invoked after this maximum inactive step to avoid the system error caused by the non-converged fission source distribution. In the same way, the uniform fission site algorithm for increasing the whole efficiency of global tallying should also be invoked after the fission source distribution has converged fully. The calculation must reach a maximum iteration step, then, this process can be stopped and the tallies can be printed. This old strategy has two defects. Firstly, the appointed maximum inactive step can only be set by experience, which will be insufficient in some cases; secondly, some iteration steps can be wasted because the precision of tallies has been enough and no one knows it. So, a new strategy is proposed in this article to overcome these defects. Based on an on-the-fly diagnostic method for the convergence of Shannon entropy sequence corresponding to the fission source distribution of each iteration step, the uniform fission site algorithm will be invoked after the iteration step whose serial number is the maximum of the first active step and the first converged step diagnosed by the above-mentioned rule. This rule will be helpful in ensuring that the uniform fission site algorithm can use enough accurate data to bias the secondary fission neutron number, thus avoiding the system error to some degree. Then, a global precision index will be calculated at each fixed step to judge whether the precision standard is reached. If so, the whole calculation is stopped. This process will be repeated until the pre-set maximum step number is reached. In this way, superfluous calculations can be skipped but the calculation precision can be guaranteed. In a word, this new strategy is beneficial to increasing the efficiency of global tallying in the Monte Carlo criticality calculation when appropriate parameters are adopted. This conclusion can be proved by the numerical result from the C5G7 benchmark model.
Traditionally, the Monte Carlo criticality calculation must set a maximum inactive step by experience to ensure that a fission source distribution has converged. The tallying process can only be invoked after this maximum inactive step to avoid the system error caused by the non-converged fission source distribution. In the same way, the uniform fission site algorithm for increasing the whole efficiency of global tallying should also be invoked after the fission source distribution has converged fully. The calculation must reach a maximum iteration step, then, this process can be stopped and the tallies can be printed. This old strategy has two defects. Firstly, the appointed maximum inactive step can only be set by experience, which will be insufficient in some cases; secondly, some iteration steps can be wasted because the precision of tallies has been enough and no one knows it. So, a new strategy is proposed in this article to overcome these defects. Based on an on-the-fly diagnostic method for the convergence of Shannon entropy sequence corresponding to the fission source distribution of each iteration step, the uniform fission site algorithm will be invoked after the iteration step whose serial number is the maximum of the first active step and the first converged step diagnosed by the above-mentioned rule. This rule will be helpful in ensuring that the uniform fission site algorithm can use enough accurate data to bias the secondary fission neutron number, thus avoiding the system error to some degree. Then, a global precision index will be calculated at each fixed step to judge whether the precision standard is reached. If so, the whole calculation is stopped. This process will be repeated until the pre-set maximum step number is reached. In this way, superfluous calculations can be skipped but the calculation precision can be guaranteed. In a word, this new strategy is beneficial to increasing the efficiency of global tallying in the Monte Carlo criticality calculation when appropriate parameters are adopted. This conclusion can be proved by the numerical result from the C5G7 benchmark model.
引文
[1] Martin W 2012 Nucl. Eng. Tech. 44 2
[2] Li G, Deng L, Zhang B Y, Li R, Shi D F, Shangguan D H,Hu Z H, Fu Y G, Ma Y 2016 Acta Phys. Sin. 65 052801(in Chinese)[李刚,邓力,张宝印,李瑞,史敦福,上官丹骅,胡泽华,付元光,马彦2016物理学报65 052801]
[3] Veluri V K, Sengupta S, Mammen S, Bhattacharya S 2018Nucl. Technol. 204 1
[4] Maul L 2018 Ann. Nucl. Energy 115 523
[5] Daniel J K, Tomas M S, Stephen C W 2012 Proceedings of PHYS OR 2012-Advances in Reactor Physics-Linking Research,Industry, and Education Knoxville, Tennessee,USA, April 15-20, 2012
[6] Daniel J K, Brian N A, Bryan R H 2013 Proceedings of M&C2013 Sun Valley, Idaho, USA, May 5-9, 2013 p2962
[7] Jessica L H, Thomas M S 2013 Proceedings of M&C 2013Sun Valley, Idaho, USA, May 5-9, 2013 p2780
[8] Shangguan D H, Deng L, Li G, Zhang B Y, Ma Y, Fu Y G,Li R, Hu X L 2016 Acta Phys. Sin. 65 062801(in Chinese)[上官丹骅,邓力,李刚,张宝印,马彦,付元光,李瑞,胡小利,2016物理学报65 062801]
[9] Shangguan D H, Li G, Zhang B Y, Deng L, Ma Y, Fu Y G,Li R, Hu X L 2016 Nucl. Sci. Eng. 182 555
[10] Ueki T, Brown F B 2005 Nucl. Sci. Eng. 149 38
[11] Natio Y, Yang J 2004 J. Nucl. Sci. Tech. 41 559
[12] Ueki T 2008 Nucl. Sci. Eng. 160 242
[13] Shangguan D H, Deng L, Li G, Zhang B Y 2018 High Power Laser and Particle Beams 30 016004
[14] Cavarec C, Perron J, Verwaerde D, West J 1994 The DECD/NEA Benchmark Calculations of Power Distributions within Assemblies(Electricite de France)
[2] Li G, Deng L, Zhang B Y, Li R, Shi D F, Shangguan D H,Hu Z H, Fu Y G, Ma Y 2016 Acta Phys. Sin. 65 052801(in Chinese)[李刚,邓力,张宝印,李瑞,史敦福,上官丹骅,胡泽华,付元光,马彦2016物理学报65 052801]
[3] Veluri V K, Sengupta S, Mammen S, Bhattacharya S 2018Nucl. Technol. 204 1
[4] Maul L 2018 Ann. Nucl. Energy 115 523
[5] Daniel J K, Tomas M S, Stephen C W 2012 Proceedings of PHYS OR 2012-Advances in Reactor Physics-Linking Research,Industry, and Education Knoxville, Tennessee,USA, April 15-20, 2012
[6] Daniel J K, Brian N A, Bryan R H 2013 Proceedings of M&C2013 Sun Valley, Idaho, USA, May 5-9, 2013 p2962
[7] Jessica L H, Thomas M S 2013 Proceedings of M&C 2013Sun Valley, Idaho, USA, May 5-9, 2013 p2780
[8] Shangguan D H, Deng L, Li G, Zhang B Y, Ma Y, Fu Y G,Li R, Hu X L 2016 Acta Phys. Sin. 65 062801(in Chinese)[上官丹骅,邓力,李刚,张宝印,马彦,付元光,李瑞,胡小利,2016物理学报65 062801]
[9] Shangguan D H, Li G, Zhang B Y, Deng L, Ma Y, Fu Y G,Li R, Hu X L 2016 Nucl. Sci. Eng. 182 555
[10] Ueki T, Brown F B 2005 Nucl. Sci. Eng. 149 38
[11] Natio Y, Yang J 2004 J. Nucl. Sci. Tech. 41 559
[12] Ueki T 2008 Nucl. Sci. Eng. 160 242
[13] Shangguan D H, Deng L, Li G, Zhang B Y 2018 High Power Laser and Particle Beams 30 016004
[14] Cavarec C, Perron J, Verwaerde D, West J 1994 The DECD/NEA Benchmark Calculations of Power Distributions within Assemblies(Electricite de France)
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |