-
Abstract:
The Auto-Importance Sampling (AIS) method is a Monte Carlo variance reduction technique proposed for deep penetration problems, which can significantly improve computational efficiency without pre-calculations for importance distribution. However, the AIS method is only validated with several simple examples, and cannot be used for coupled neutron-photon transport. This paper presents improved algorithms for the AIS method, including particle transport, fictitious particle creation and adjustment, fictitious surface geometry, random number allocation and calculation of the estimated relative error. These improvements allow the AIS method to be applied to complicated deep penetration problems with complex geometry and multiple materials. A Completely coupled Neutron-Photon Auto-Importance Sampling (CNP-AIS) method is proposed to solve the deep penetration problems of coupled neutron-photon transport using the improved algorithms. The NUREG/CR-6115 PWR benchmark was calculated by using the methods of CNP-AIS, geometry splitting with Russian roulette and analog Monte Carlo, respectively. The calculation results of CNP-AIS are in good agreement with those of geometry splitting with Russian roulette and the benchmark solutions. The computational efficiency of CNP-AIS for both neutron and photon is much better than that of geometry splitting with Russian roulette in most cases, and increased by several orders of magnitude compared with that of the analog Monte Carlo.
-
-
References
[1]
|
H. C. Gupta, Ann. Nucl. Energ., 11(6):283-288(1984) |
[2]
|
R. P. Gardner, M. Mickael, K. Verghese et al, Nucl. Sci. Eng., 98:1(1):51-63(1988). |
[3]
|
A. Haghighat, J. C. Wagner, Prog. Nucl. Energ., 42(1):25-53(2003) |
[4]
|
H. P. Smith, J. C. Wagner, Nucl. Sci. Eng., 149(1):23-37(2005) |
[5]
|
L. J. Yuan, Y. X. Chen, J. R. Han, At. Energ. Sci. Technol., 48(3):407-411(2014) (in Chinese) |
[6]
|
W. T. Urban, T. J. Seed, D. J. Dudziak, Nucleonic analysis of a preliminary design for the ETF neutral-beam-injector duct shielding, in 4th Topical Meeting on the Technology of Controlled Nuclear Fusion, (USA, 1981), p. 479 |
[7]
|
M. Kurosawa, Radiat. Prot. Dosim., 116(1-4 Part 2):513-517(2005). |
[8]
|
J. L. Li, C. Y. Li, Z. Wu, Prog. Nucl. Sci. Technol., 2:732-737(2011) |
[9]
|
C. Y. Li, Research of Point Flux Estimation and Deep Penetration in Monte Carlo Methods, M.S. Thesis (Beijing, Tsinghua Univ. 2008) (in Chinese) |
[10]
|
J. Temsamani,T. Pederson, MCNP-A General Monte Carlo N-Particle Transport Code, Version 5. (Los Alamos National Laboratory, Oak Ridge, TN, 2003) |
[11]
|
J. J. Fan, Research of Rare but Important Events Simulation in Monte Carlo Methods, Ph.D. Thesis (Beijing, Tsinghua Univ. 2004) (in Chinese) |
[12]
|
J. F. Carew, PWR and BWR pressure vessel fluence calculation benchmark problems and solutions. (Division of Engineering Technology, Office of Nuclear Regulatory Research, US Nuclear Regulatory Commission, 2001) |
-
[1] |
Ronghao Hu
, Qike Gu
, Kejian Shi
, Zezhong Wei
, Meng Lv
, Shiyang Zou
, Yongkun Ding
. Polarized neutron beams from polarized deuterium-tritium fusion with applications to magnetic field imaging in high-energy-density plasmas. Chinese Physics C,
2025, 49(12): 124102.
doi: 10.1088/1674-1137/adec4f
|
[2] |
GUO Yan-Qing
, SONG Jie
. Quantitative conditions for the formation of p-wave neutron halos. Chinese Physics C,
2011, 35(2): 158-162.
doi: 10.1088/1674-1137/35/2/010
|
-
Access
-
-