快中子临界装置大厅辐射屏蔽门研制及性能验证

为提升快中子临界装置的实验能力，在实验大厅旁边扩建了附属建筑物，在实体连接位置形成了一个样品传输通道。为了保证工作人员的辐射安全，需要对通道进行屏蔽。采用蒙特卡罗方法进行屏蔽门的物理设计，确定了含硼石蜡为中子屏蔽材料，不锈钢为光子屏蔽材料。为保证硼在石蜡层上的均匀分布，防止石蜡内部形成空洞，采用了分层分次工艺进行屏蔽门浇铸。为保证屏蔽门对通道的有效覆盖，采用了分步工艺进行安装。辐射剂量监测结果表明，人员日常工作区域的辐射有效剂量为0.125 mSv/a，小于建设项目管理目标值2 mSv/a，远小于《电离辐射防护与辐射源安全基本标准》规定的放射性工作人员年剂量限值20 mSv/a，屏蔽门的研制满足设计和使用要求。

Development and Performance Verification of Radiation Screen Door in Fast Critical Assembly Hall

In order to enhance the experimental ability of the fast critical assembly, the ancillary buildings was extended beside the critical experiment hall, a sample transmission channel was formed in the physical connection position. In order to ensure personnel the safety of radiation, need to screen out channel. Physical design by using the Monte Carlo method for screen door, the boron containing paraffin as neutron shielding material, stainless steel as photon shielding material. In order to ensure the uniform distribution of boron in the paraffin layer, prevent paraffin internal cavities, the stratification technics was adopted to cast screen door. In order to ensure the effective coverage of channel, using a step by step process for installation. The radiation dose monitoring shows, in personnel daily work of the regional annual radiation effective dose was 0.125 mSv, that less than 2 mSv the limit value of construction project management, far less than the 20 mSv the basic standards for protection against ionizing radiation and for the safety of radiation sources , screen door development to meet the design and use requirements.