基于DT中子源的模拟现场中子谱装置结构设计方法研究

摘要/Abstract

摘要： 中子剂量与能量关联性较大,针对校准场的能谱与现场工作场所的能谱不同导致校准设备的现场实用存在剂量测量值与实际值偏差较大的问题,采用模拟现场谱技术校准设备将使剂量测量更准确。结合压水堆及核燃料循环现场中子谱的特点,基于DT中子源研究压水堆场所模拟现场中子谱模块化构建方法和装置结构设计方法研究,通过分析T(d,n)⁴He反应能谱和角分布规律,采用平均能量14.1 MeV高斯分布各向同性发射的点源近似DT中子源;根据中子与物质相互作用截面,选择14种备选材料,分析相对中子注量比和平均中子能量,从中子倍增、能量衰减、能谱调节及实用性角度对构建模拟谱装置的材料进行了选型。选择压水堆主泵房间和反应堆厂房两个现场目标谱,设计主慢化组件、调节层和反射组件,构建了针对两目标谱的模拟现场谱及装置结构。结果表明,建立的模拟现场谱构建方法有效,模拟谱与归一化目标谱匹配良好,且采用模块化设计,可拓展性强,可以适应多种现场目标谱构建模拟谱。

关键词: 模拟工作现场中子谱, 蒙特卡罗模拟, 中子慢化, Geant4

Abstract: Neutron dose is highly dependent on its energy. However, the energy spectrum of the calibration field is different from workplace, which could lead to a large deviation in the measurement of neutron dose at workplace. Using simulation workplace neutron spectrum for equipment calibration will improve the accuracy of neutron dose measurements. In this paper, the modular construction method of the simulated workplace neutron spectrum and the structural design method of the device were studied based on the DT neutron source, the simulated spectrum with the characteristics of workplace neutron spectrum at pressurized water reactors (PWR), and its fuel cycle. By analyzing the T(d, n)⁴He reaction emission neutron’s energy spectrum and angular distribution law, a point source with an average energy of 14.1 MeV Gaussian distribution and isotropic emission was used to approximate the DT neutron source. 14 alternative materials were selected according to the interaction cross-section of neutron and matter, the relative neutron fluence ratio and average neutron energy were analyzed. And the materials for constructing the simulation workplace neutron spectrum device were selected from the perspectives of neutron multiplication, energy attenuation, energy spectrum adjustment, and practicality. Two workplace neutron spectrum of the pump room and reactor hall were selected as target spectrum. Main moderation assembly, modulating layers and reflector assembly were designed. The simulated neutron spectrum and device structure for the two workplace target spectrum were constructed. The results show that the construction method of the simulated workplace neutron spectrum described in this paper is effective, and the modular design is highly expandable, which can be adapted to a variety of workplace target spectrum to construct the simulated spectrum.

Key words: simulated workplace neutron spectrum, Monte Carlo simulation, neutron moderation, Geant4

中图分类号:

TL72

李会, 李德源, 闫学文, 张鹏鹏, 陈法国, 李华. 基于DT中子源的模拟现场中子谱装置结构设计方法研究[J]. 辐射防护, 2023, 43(3): 209-217.

LI Hui, LI Deyuan, YAN Xuewen, ZHANG Pengpeng, CHEN Faguo, LI Hua. Research on the module structure design of simulation workplace neutron spectrum device based on DT neutron source[J]. RADIATION PROTECTION, 2023, 43(3): 209-217.

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