Speaker
Liqin Hu
(Institute of Nuclear Energy Safety Technology)
Description
Due to the complexity of fusion reactors on geometry and neutron physics, the Monte Carlo (MC) methods have been broadly adopted in fusion nuclear design and analysis. But for calculations that require obtaining a detailed global flux map, such as the shutdown dose rate analysis, analog MC simulations usually cost a prohibitive long run time. To make such analysis computational practicable, it is necessary to adopt an efficient global variance reduction (GVR) method.
This paper proposed a new mesh weight window based GVR method, named Global Weight Window Generator (GWWG). For each weight window cell, this method calculates its importance as the expected contribution to the particle density uniformity generated by a unit weight particle entering this cell. This contribution is calculated in a way trying to reach a balance between penetrating deeper by splitting and simulating more source particles per unit time. It also exploits an efficient and fully automatic iteration scheme to speed up the weight window generation. The development of the GWWG method is based on the SuperMC code, which is a general, intelligent, accurate and precise simulation software system for the nuclear design and radiation safety evaluation.
To validate the performance of the GWWG method, series of tests have been performed with the ITER benchmark, ITER Alite and the ITER Clite model, calculating the neutron flux over a mesh tally covering the entire reactor. All the tests have showed a substantial increase in computing efficiency compared with the analog case. The highest speedup in the MC figure of merit, ~249 times, is achieved with the ITER Alite model. These calculations demonstrate the ability of the GWWG method to greatly enhance the efficiency of global flux map simulation of complex models.
Keywords: Monte Carlo; SuperMC; Global variance reduction
Co-authors
Guangyao Sun
(Institute of Nuclear Energy Safety Technology,Chinese Academy Sciences, Hefei, Anhui, China)
Jing Song
(Institute of Nuclear Energy Safety Technology,Chinese Academy Sciences, Hefei, Anhui, China)
Lijuan Hao
(Institute of Nuclear Energy Safety Technology,Chinese Academy Sciences, Hefei, Anhui, China)
Liqin Hu
(Institute of Nuclear Energy Safety Technology,Chinese Academy Sciences, Hefei, Anhui, China)
Shu Zhang
(Institute of Nuclear Energy Safety Technology,Chinese Academy Sciences, Hefei, Anhui, China)
