田湾核电站主泵检修去污方案的优化选择和分析

Optimization and Analysis of Main Coolant Pump Decontamination Schemes in Tianwan Nuclear Power Station

主泵解体检修是核电站大修期间的重要工作之一,而降低主泵检修集体剂量最主要的措施是对其水力部件进行放射性去污,同时要在保证设备安全的前提下优化去污工艺,获得最大的去污因子。田湾核电站在前两次大修中对主泵水力部件分别采用了超声波去污、氧化-还原去污、超声波+氧化-还原去污等三种去污工艺。本文通过对不同去污工艺的对比,分析了不同去污工艺的优缺点以及对集体剂量和大修工期等的影响,从辐射防护的角度优先选择了超声波+氧化-还原去污方案,获得了较大的去污因子,大大降低了检修人员的个人剂量和大修集体剂量,取得了良好的效果。

The overhaul of main coolant pumps （MCP） is one of important work during the general overhaul of nuclear power station,and the main measure taken to reduce collective dose is to decontaminate the hydraulic component of MCP.Tianwan Nuclear Power Station has taken three decontamination technologies in former overhauls,including ultrasonic decontamination,oxidation-deoxidization and ultrasonic and oxidation-deoxidization.This paper analyses the merits and demerits of decontamination technologies,and evaluates these technologies＇ influence on collective dose and the time limit for MCP overhaul.It is concluded that ultrasonic and oxidation-deoxidization technology is the optimum choice.This technology could achieve a maximum decontamination factor,and could markedly reduce collective dose.