蒸汽发生器装拆堵板的辐射防护最优化

ALARA ACTIONS DURING INSTALLATION/REMOVAL OF NOZZLE DAMS IN PRIMARY WATER CHAMBER OF SG

蒸汽发生器一次侧水室装拆堵板是核电站大修的一项重要操作 ,具有较大的辐射风险。本文主要介绍了大亚湾核电站在安装和拆卸堵板工作中 ,实施辐射防护最优化 (ALARA)的方法和效果。通过风险分析、简化工作内容 (采用假堵板 )、合理安排人力、强化模拟培训等工作前的ALARA计划和准备 ,以及改进和完善防护措施、加强现场监督和跟踪、注重经验反馈等工作过程的ALARA控制 ,大大地提高了工作效率 ,缩短了作业时间 ,使装拆堵板工作 (按照三台蒸汽发生器 ,6个一次侧水室统计 )的集体剂量约降低至原来的 1 / 5 ,最大个人受照剂量约降低至原来的 1 /

The removal and installation of nozzle dams (RIND) from primary water chamber of steam generator (SG) is one of the essential maintenance jobs with high radiation risk during outage in a nuclear power plant. This paper introduces the method and effect of implementing ALARA principle for RIND by radiation protection (RP) staff in Daya Bay nuclear power plant.With ALARA planing and preparing prior to RIND such as risk analysis, simplification of work process, proper arrangement of human resource, training on mock-up,as well as work management for ALARA through improving radiation protection measures, strengthening supervision on site, enforcing experience feed back during RIND,working efficiency has been raised, working time shortened,collective dose reduced to 1/5 of that before and maximum individual exposure dose to 1/3 of that before. (