EAST在不同加热模式下的辐射响应研究  

Radiation response research under different heating modes of EAST

作　　者：周梦洁 胡立群 钟国强 黄良胜 李凯 周瑞杰[1] 洪兵 肖敏 张瑞雪 ZHOU Mengjie;HU Liqun;ZHONG Guoqiang;HUANG Liangsheng;LI Kai;ZHOU Ruijie;HONG Bing;XIAO Min;ZHANG Ruixue((Institute of Plasma Physics,Chinese Academy of Sciences,Hefei 230031,China;University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院等离子体物理研究所,合肥230031 [2]中国科学技术大学,合肥230026

出　　处：《核技术》2020年第3期80-86,共7页Nuclear Techniques

基　　金：国家自然科学基金(No.11605241、 No.11575249);国家磁约束核聚变能研究专项(No.2015GB103000)资助~~

摘　　要：利用EAST(Experimental Advanced Superconducting Tokamak)上的在线辐射剂量监测系统,对氘氘等离子体实验期间各种加热模式下装置主机厅内中子、γ剂量进行测量。对比分析了欧姆加热、低杂波加热、中性束注入加热,以及中性束与射频波协同加热实验时的中子、γ辐射强度随时间演化的规律。结果显示:在纯欧姆加热模式,辐射剂量主要来源于逃逸电子轫致辐射产生的高能γ(X)射线和光中子;低杂波辅助加热时,通常会出现环电压下降的现象,离子温度和聚变反应率提高有限,而逃逸电子产生的韧致辐射却被有效抑制,使得总体辐射剂量水平反而低于纯欧姆加热模式;中性束注入加热时,束靶反应使得中子产额提高2~3个数量级,聚变中子以及中子与周围物质核反应产生的γ射线成为辐射剂量的主要来源。通过统计归纳得到在中性束注入加热时,中子周围剂量当量与γ周围剂量当量存在近似的线性关系。该线性关系对于中性束与各种射频波协同加热实验时,中子、γ射线来源于多种途径的情形并不完全适用。[Background] A pulsed hybrid radiation field will be generated by Experimental Advanced Superconducting Tokamak(EAST) during deuterium plasma discharge. [Purpose] This study aims to explore the radiation doses of EAST under different heating modes to ensure the radiation safety. [Methods] The on-line radiation dose monitoring system of EAST was used to measure the neutrons and γ-rays radiation in the main hall of the device under various heating modes during the deuterium plasma experiment. Evolution of neutron and γradiation intensity with time under ohmic heating, lower hybrid waves heating, neutral beam injection heating, and neutral beam and radio frequency waves collaborative heating were compared and analyzed. [Results] The results showed that the main sources of radiation dose were high-energy γ(X)-rays and photoneutrons produced by runaway electrons bremsstrahlung radiation in the pure ohmic heating mode. The drop of the loop voltage effectively inhibited the generation of runaway electrons, and the radiation dose level under lower hybrid waves heating mode was lower than that of ohmic heating mode. The beam target reaction increased the neutron yield by 2-3 orders of magnitude.The approximate linear relationship between neutron and γ ambient dose equivalent was found by statistical induction under neutral beam injection heating mode, but it was not completely applicable to the situation that the neutrons andγ-rays came from various ways when the neutral beam and radio frequency waves were heated together.[Conclusion] The study can lay a good foundation for the establishment of fusion radiation dose database.

关 键 词：EAST 辐射剂量 加热模式 中子 Γ射线 

分 类 号：TL75[核科学技术—辐射防护及环境保护] TL62