Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (3): 30501-030501.doi: 10.11889/j.0253-3219.2016.hjs.39.030501

• NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH • Previous Articles     Next Articles

Application and comparison of global variance reduction methods employed in Monte Carlo neutron transport for CFETR

NIE Xingchen1, LI Jia1, ZHAO Pinghui1, ZHU Qingjun2   

  1. 1 School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230027, China;
    2 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
  • Received:2015-10-22 Revised:2015-12-24 Online:2016-03-10 Published:2016-03-11
  • Supported by:

    Supported by National Special Project for Magnetic Confined Nuclear Fusion Energy (No.2013GB108004, No.2015GB108002) and the National Natural Science Foundation of China (No.11175207)

Abstract:

Background: For the detailed Monte Carlo radiation transport, which possesses global characteristics, traditional MCNP Localized Variance Reduction (LVR) methods can hardly perform well. Global Variance Reduction (GVR) method is an effective way. Purpose: This study aims to decrease the global variance of Monte Carlo radiation transport calculations for Chinese Fusion Engineering Testing Reactor (CFETR). Methods: According to different information of neutron distribution, six kinds of GVR methods were implied and compared in a cylinder CFETR neutronics model. Global figure of merit (FOMG), standard deviation (σ) and the percentage of scoring were analyzed. Based on predecessors' research, other kinds of new GVR methods (energy, tracks) were applied in this calculation. Results: In the point of GVR methods, FOMG increased dramatically, spatial variation in relative errors was more gradual, and the scoring was higher, compared with AN. The GVR method based on neutron flux achieved the global calculation efficiency of 6.43 times that of AN. Apart from that, the GVR method based on neutron energy can also be a practical GVR kind, achieving the global calculation efficiency of 5.11 times that of AN. Conclusion: The GVR method based on neutron flux can performed best that has a well function of global variance reduction, achieving the global calculation efficiency.

Key words: Global variance reduction, Weight window, Monte Carlo, MCNP, Neutronics

CLC Number: 

  • TL62