提高单板钴源剂量率MCNP计算效率的模拟研究  

Study on improving MCNP computational efficiency of dose rate for a single-rack cobalt irradiation facility

作　　者：李磊[1] 李晓燕[1] 黄玮[1] 蒋树斌[1] 伍晓利[1] 杨桂霞[1] 

机构地区：[1]中国工程物理研究院核物理与化学研究所,绵阳621900

出　　处：《核技术》2015年第3期18-24,共7页Nuclear Techniques

摘　　要：蒙特卡罗方法是目前准确的吸收剂量率计算方法,但其较长的模拟耗时阻碍了它在工业钴源辐射加工和辐照实验中的应用。模拟耗时、模拟精度以及模拟值与实测值的相对偏差是表征蒙特卡罗计算效率的重要指标。针对8.4 PBq的单板钴源辐照装置,讨论了并行线程数、记数方法、记数栅元尺寸、γ致电子的处理方式和截断能5种参数对蒙特卡罗程序MCNP吸收剂量率计算效率的影响。利用实验测量结合模拟试算的方法,给出了在保证一定精度和相对偏差前提下,使得模拟耗时最少的参数组合,提高了MCNP计算效率。结果如下:超线程模式下的并行计算、*F6记数方法、栅元边长为1 cm、γ输运模式、γ截断能为100 ke V。Background： Monte Carlo method is regarded as the most accurate method for dose rate calculation at present, whereas its time-consuming defect increases complication for its application in industrial irradiation processing and experiment. Purpose： For a single-rack cobalt irradiation facility with loaded activity of 8.4 PBq, a study of optimizing MCNP （Monte Carlo N Particle Transport Code） parameters was done to improve computational efficiency of dose rate. Methods： The effects of five parameters on MCNP computational efficiency, including the thread numbers of parallel computation, tally method, cell size, cutoff energy, and methods dealing with γ-induced electrons were discussed. Results： With certain precision and relative error, the least time-consuming situation was achieved with a set of five parameters, including parallel computation with hyper-thread mode, ＊F6 tally, cell size of 1 cm, γ transport mode and γ-cutoff energy of 100 keV. Conclusion： In this work, the cost of time was reduced about 57 times, and the improvement of MCNP computational efficiency was realized.

关 键 词：单板钴源辐照装置 吸收剂量率 MCNP 计算效率 

分 类 号：TL929[核科学技术—核燃料循环与材料]