CFETR NNBI验证样机X射线辐射屏蔽设计
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摘要
中国聚变工程实验堆(China Fusion Engineering Test Reactor,CFETR)负离子源中性束系统(Negative ion based Neutral Beam Injection system,NNBI)验证样机拟引出负氢离子束。离子束在产生和传输过程中,束粒子与样机结构材料固体靶相互碰撞,将产生韧致辐射(X射线),当CFETR NNBI验证样机运行在设计的参数下(束能量为200 keV,流强20 A),距离离子源真空壁(真空壁厚2 cm)1 m处的壁外剂量率高于一般工作人员辐射剂量率限值(10μSv·h~(-1))。为了降低辐射剂量率,确保工作人员辐射安全,本文通过对样机进行辐射屏蔽理论计算与模拟研究,提出了将样机下沉加铅板的屏蔽设计方案,并开展了辐射模拟分析。结果表明:该方案满足CFETR NNBI验证样机运行的辐射安全要求。
[Background] China fusion engineering test reactor(CFETR) negative ion based neutral beam injection system(NNBI) prototype was designed for hydrogen beam operation. When the NNBI prototype works, the energetic particles collide with the solid targets of the prototype structural material during production and transmission to produce bremsstrahlung. When the CFETR NNBI prototype is designed to operate with a beam energy of 200 keV and beam current of 20 A, the dose rate outside the vacuum wall is higher than the limit dose rates of general worker radiation(10 μSv·h~(-1)). [Purpose] This study aims to reduce the radiation dose rate of the CFETR NNBI with hydrogen beam energy of 200 keV. [Methods] The radiation dose of the prototype was simulated by the radiation shielding theory. The shielding design scheme of sinking the prototype with lead plate was put forward and evaluated.[Results] When the CFETR NNBI is placed underground and shielding layer on the top, the outside dose rate at 1 m from vacuum wall(with 2 cm thickness) of ion source(200 keV, 20 A) is below the limit. [Conclusion] The design scheme can meet the radiation safety standards when the CFETR NNBI prototype operated with radiation shielding.
[Background] China fusion engineering test reactor(CFETR) negative ion based neutral beam injection system(NNBI) prototype was designed for hydrogen beam operation. When the NNBI prototype works, the energetic particles collide with the solid targets of the prototype structural material during production and transmission to produce bremsstrahlung. When the CFETR NNBI prototype is designed to operate with a beam energy of 200 keV and beam current of 20 A, the dose rate outside the vacuum wall is higher than the limit dose rates of general worker radiation(10 μSv·h~(-1)). [Purpose] This study aims to reduce the radiation dose rate of the CFETR NNBI with hydrogen beam energy of 200 keV. [Methods] The radiation dose of the prototype was simulated by the radiation shielding theory. The shielding design scheme of sinking the prototype with lead plate was put forward and evaluated.[Results] When the CFETR NNBI is placed underground and shielding layer on the top, the outside dose rate at 1 m from vacuum wall(with 2 cm thickness) of ion source(200 keV, 20 A) is below the limit. [Conclusion] The design scheme can meet the radiation safety standards when the CFETR NNBI prototype operated with radiation shielding.
引文
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9杨勇,张圆月,刘志宏,等.医用诊断X射线剂量探测技术概述[J].中国测试,2005,31(4):94-96.DOI:10.3969/j.issn.1674-5124.2005.04.033.YANG Yong,ZHANG Yuanyue,LIU Zhihong,et al.Introduction of diagnose X-ray dose testing technology[J].China Measurement Technology,2005,31(4):94-96.DOI:10.3969/j.issn.1674-5124.2005.04.033.
2 Zhou W,Fang X Y,Fang J,et al.Numerical and experimental analysis of AC loss for CFETR CS model coil[J].Nuclear Science and Techniques,2017,28(10):142.DOI:10.1007/s41365-017-0301-0.
3 Staebler A,Fantz U,Franzen P,et al.Development of a RF-driven ion source for the ITER NBI system[J].Fusion Engineering&Design,2009,84(2):265-268.DOI:10.1016/j.fusengdes.2008.11.036.
4胡纯栋,李梦婷,谢亚红,等.CFETR中性束系统验证样机充氢运行辐射分析与初步模拟计算[J].核技术,2018,41(9):090603.DOI:10.11889/j.0253-3219.2018.hjs.41.090603.HU Chundong,LI Mengting,XIE Yahong,et al.Radiation analysis and simulation of the CFETR neutral beam system prototype with hydrogen beam[J].Nuclear Techniques,2018,41(9):090603.DOI:10.11889/j.0253-3219.2018.hjs.41.090603.
5王建龙.辐射防护基础教程[M].北京:清华大学出版社,2012.WANG Jianlong.Basic tutorial of radiation protection[M].Beijing:Tsinghua University Press,2012.
6俞君,万玲,娄云,等.X射线探伤机房的辐射屏蔽设计[J].首都公共卫生,2012,06(2):75-77.DOI:10.3969/j.issn.1673-7830.2012.02.006.YU Jun,WAN Ling,LOU Yun,et al.Radiation shielding design of industrial X-ray radiography room[J].Capital Journal of Public Health,2012,06(2):75-77.DOI:10.3969/j.issn.1673-7830.2012.02.006.
7 Kutcher G J.Radiation protection design guidelines for0.1 to 100 MeV particle accelerator facilities[J].Medical Physics,1978,5(1):73.DOI:10.1118/1.594404.
8 ICRP.Conversion coefficients for use in radiological protection against external radiation[J].Annals of the ICRP,1996,26(5):3-4.DOI:10.1016/j.jnucmat.2015.01.055.
9杨勇,张圆月,刘志宏,等.医用诊断X射线剂量探测技术概述[J].中国测试,2005,31(4):94-96.DOI:10.3969/j.issn.1674-5124.2005.04.033.YANG Yong,ZHANG Yuanyue,LIU Zhihong,et al.Introduction of diagnose X-ray dose testing technology[J].China Measurement Technology,2005,31(4):94-96.DOI:10.3969/j.issn.1674-5124.2005.04.033.