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摘要: 为了满足钍基熔盐堆对核数据的需求,中国科学院上海应用物理研究所自行设计并建造了紧凑型的15 MeV电子加速器驱动的白光中子源。电子直线加速器、中子产生靶以及探测器系统处于同一个实验大厅,中子/伽马射线本底较高,原有屏蔽并不能满足在低能区进行热中子物理实验测量的低中子本底需求。为了降低热中子本底,提高在热区的测量能力,需要对中子源进行局部屏蔽。根据调试运行经验以及模拟计算结果,分析了中子伽马射线本底的来源,利用MCNP5模拟计算了混凝土、铅、含硼聚乙烯对中子/伽马射线的屏蔽效果,优化设计了局部屏蔽方案。模拟计算结果显示,该屏蔽方案可将热中子本底降低三个量级,伽马本底降低两个量级。屏蔽后的实验测量结果表明,探测器处的有效热中子与本底热中子的比值达到约100:1,屏蔽效果显著,为后续在热中子能区顺利开展中子物理测量实验奠定了基础。Abstract: In order to meet the nuclear data requirement of Thorium Molten Salt Reactor (TMSR), a compact photoneutron source (PNS) driven by a 15 MeV electron LINAC was designed and built up by Shanghai Institute of Applied Physics. All devices including the LINAC, the neutron production target and the detector systems were all arranged in a shared hall, causing high backgrounds of neutron and γ-ray. The existing shields could not meet the requirements of low neutron background for the measurement in the thermal neutron energy regions. Therefore, more shields are needed to further reduce the neutron and γ-ray backgrounds. According to the analysis of neutron background source terms and the simulation of shielding effects of lead, concrete and boron polyethylene, the new local shields was designed. The MCNP5 simulation results show that, the new local shields can reduce the thermal neutron background by three orders of magnitude and the γ-ray background by two orders of magnitude. The experimental results with the new local shields show that, the ratio of effective thermal neutron to background thermal neutron is up to 100:1, which is of great significance for launching the foreseen physics program in the thermal neutron energy regions.
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Key words:
- TMSR /
- photoneutron source /
- local shielding /
- Monte Carlo simulation /
- background
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[1] KONING A J, BLOMGREN J, JACQMIN R, et al. CANDIDE: Nuclear Data for Sustainable Nuclear Energy[R]. JRC Scientific and Technical Reports, EUR 23977 EN, 2009. [2] COLONNA N, BELLONI F, BERTHOUMIEUX E, et al. Energy & Environmental Science, 2010, 3(12): 1910. doi: 10.1039/c0ee00108b [3] COCEVA C, FRISONI M, MAGNANI M, et al. Nucl Instr and Meth A, 2002, 489(1): 346. doi: 10.1016/S0168-9002(02)00903-8 [4] KIM G N, KOVALCHUK V, LEE Y S, et al. Nucl Instr and Meth A, 2002, 485(3): 458. doi: 10.1016/s0168-9002(01)02115-5 [5] 江绵恒, 徐洪杰, 戴志敏. 中国科学院院刊, 2012, 27(3): 366. JIANG Mianheng, XU Hongjie, DAI Zhimin. Bulletin of the Chinese Academy of Sciences, 2012, 27(3): 366. (in Chinese) [6] 王宏伟, 陈金根, 蔡翔舟, 等. 核技术, 2014, 37(10): 100522. doi: 10.11889/j.0253-3219.2014.hjs.37.100522 WANG Hongwei, CHEN Jingen, CAI Xiangzhou, et al. Nuclear Techniques, 2014, 37(10): 100522. (in Chinese) doi: 10.11889/j.0253-3219.2014.hjs.37.100522 [7] 朱亮, 刘龙祥, 王宏伟, 等. 原子核物理评论, 2016, 33(03): 308. doi: 10.11804/NuclPhysRev.33.03.308 ZHU Liang, LIU Longxiang, WANG Hongwei, et al. Nuclear Physics Review, 2016, 33(03): 308. (in Chinese) doi: 10.11804/NuclPhysRev.33.03.308 [8] PRIYADA P, ASHWINI U, SARKAR P K. Nuclear Instr and Meth A, 2016, 819: 139. doi: 10.1016/j.nima.2016.02.095 [9] 李洋. CR-39固体核径迹探测器应用于中子探测的实验研究[D]. 上海: 中国科学院大学, 2016. LI Yang. Experimental Study of CR-39 Solid State Nuclear Track Detectors Applied in Neutron Detection[D]. Shanghai: University of Chinese Academy of Sciences, 2016. (in Chinese) [10] X-5 Monte Carlo Team. MCNP - A General Monte Carlo N-Particle Transport Code, Version 5[R]. Los Alamos National Laboratory Report LA-UR-03-1987, Apr. 2003, Revised Mar. 2005. [11] WEIDLICH G A, NUESCH C E, FUERY J J. Medical Dosimetry Official Journal of the American Association of Medical Dosimetrists, 1996, 21(3): 165-167. doi: 10.1016/0958-3947(96)00078-7 [12] DAVIS A, TURNER A. Fusion Engineering & Design, 2011, 86: 2670. doi: 10.1016/j.fusengdes.2011.01.059 [13] 王小鹤, 胡继峰, 陈金根, 等. 原子能科学技术, 2019, 53(8): 1466. doi: 10.7538/yzk.2018.youxian.0749 WANG Xiaohe, HU Jifeng, CHEN Jingen, et al. Atomic Energy Science and Technology, 2019, 53(8): 1466. (in Chinese) doi: 10.7538/yzk.2018.youxian.0749 [14] WILLIAM P. SWANSON. Radiological Safety Aspects of the Operation of Electron Linear Accelerators[R]. Vienna: International Atomic Energy Agency, 1979. [15] 王炳衡, 刘志宏, 施工, 等. 核科学与工程, 2006, 26(3): 220. doi: 10.3321/j.issn:0258-0918.2006.03.006 WANG Bingheng, LIU Zhihong, SHI Gong, et al. Chinese Journal of Nuclear Science and Engineering, 2006, 26(3): 220. (in Chinese) doi: 10.3321/j.issn:0258-0918.2006.03.006 [16] GURU P S, PARTHASARADHI P, BLOOMER W D, et al. Radiation Physics and Chemistry, 1998, 53(4): 361. doi: 10.1016/S0969-806X(98)00130-3 [17] LIU L X., WANG H W, MA Y G, et al Nucl Instr and Meth B, 2017, 401: 158. doi: 10.1016/j.nimb.2017.08.022
TMSR白光中子源本底屏蔽设计
doi: 10.11804/NuclPhysRev.37.2019CNPC38
- 收稿日期: 2020-01-03
- 修回日期: 2020-04-16
- 网络出版日期: 2020-09-30
- 刊出日期: 2020-09-20
摘要: 为了满足钍基熔盐堆对核数据的需求,中国科学院上海应用物理研究所自行设计并建造了紧凑型的15 MeV电子加速器驱动的白光中子源。电子直线加速器、中子产生靶以及探测器系统处于同一个实验大厅,中子/伽马射线本底较高,原有屏蔽并不能满足在低能区进行热中子物理实验测量的低中子本底需求。为了降低热中子本底,提高在热区的测量能力,需要对中子源进行局部屏蔽。根据调试运行经验以及模拟计算结果,分析了中子伽马射线本底的来源,利用MCNP5模拟计算了混凝土、铅、含硼聚乙烯对中子/伽马射线的屏蔽效果,优化设计了局部屏蔽方案。模拟计算结果显示,该屏蔽方案可将热中子本底降低三个量级,伽马本底降低两个量级。屏蔽后的实验测量结果表明,探测器处的有效热中子与本底热中子的比值达到约100:1,屏蔽效果显著,为后续在热中子能区顺利开展中子物理测量实验奠定了基础。
English Abstract
Background Shielding Design for TMSR Photoneutron Source
- Received Date: 2020-01-03
- Rev Recd Date: 2020-04-16
- Available Online: 2020-09-30
- Publish Date: 2020-09-20
-
Keywords:
- TMSR /
- photoneutron source /
- local shielding /
- Monte Carlo simulation /
- background
Abstract: In order to meet the nuclear data requirement of Thorium Molten Salt Reactor (TMSR), a compact photoneutron source (PNS) driven by a 15 MeV electron LINAC was designed and built up by Shanghai Institute of Applied Physics. All devices including the LINAC, the neutron production target and the detector systems were all arranged in a shared hall, causing high backgrounds of neutron and γ-ray. The existing shields could not meet the requirements of low neutron background for the measurement in the thermal neutron energy regions. Therefore, more shields are needed to further reduce the neutron and γ-ray backgrounds. According to the analysis of neutron background source terms and the simulation of shielding effects of lead, concrete and boron polyethylene, the new local shields was designed. The MCNP5 simulation results show that, the new local shields can reduce the thermal neutron background by three orders of magnitude and the γ-ray background by two orders of magnitude. The experimental results with the new local shields show that, the ratio of effective thermal neutron to background thermal neutron is up to 100:1, which is of great significance for launching the foreseen physics program in the thermal neutron energy regions.
引用本文: | 王小鹤, 胡继峰, 刘龙祥, 王宏伟, 蔡翔舟, 陈金根, 王纳秀, 姜炳, 郭子安, 韩建龙. TMSR白光中子源本底屏蔽设计[J]. 原子核物理评论, 2020, 37(3): 777-783. doi: 10.11804/NuclPhysRev.37.2019CNPC38 |
Citation: | Xiaohe WANG, Jifeng HU, Longxiang LIU, Hongwei WANG, Xiangzhou CAI, Jingen CHEN, Naxiu WANG, Bing JIANG, Zian GUO, Jianlong HAN. Background Shielding Design for TMSR Photoneutron Source[J]. Nuclear Physics Review, 2020, 37(3): 777-783. doi: 10.11804/NuclPhysRev.37.2019CNPC38 |