热中子照相装置屏蔽的蒙特卡罗模拟

中子照相装置的屏蔽对降低反应堆大厅本底及提高中子照相质量具有重要意义。使用蒙特卡罗模拟方法，对热中子照相装置各组成部分的屏蔽进行模拟计算。结果表明：在照相装置的准直器部分使用厚130cm、密度4.6t/m3的重混凝土，飞行管部分使用厚75cm、密度3.6t/m3的重混凝土可保证屏蔽外的辐射当量剂量达到反应堆大厅的监督区要求。

Monte-Carlo Simulations for Shielding of Thermal Neutron Radiograph Facility

The shielding of neutron radiograph facility is important for reduce the background of reactor hall as well as enhancing quality of neutron radiograph. In this study, Monte-Carlo simulation was utilized to conduct the calculation on the shielding of thermal neutron radiograph facility. The simulation result indicates that, in the case of heavy concrete (density 4.6 t/m3) in the thickness of 1.3 m is utilized for the collimator of the facility, as well as heavy concrete (density 3.6 t/m3) in the thickness of 75 cm is utilized for the flight tube, the dose rate outside shielding is able to reach the requirement of radiation levels of reactor hall.