6000型水位测量仪表测量偏差分析与处理

6000 Type Water Level Measuring Instrument Measurement Deviation Analysis and Processing

6000型堆芯水位测量仪表用于反应堆正常充、排水期间为操作员提供反应堆水位信息,在反应堆发生冷却剂丧失事故时监测反应堆堆芯淹没情况,保证机组安全。某核电机组6000型堆芯水位测量仪表正负压侧安装高度与设计存在偏差,导致测量的结果不满足设计要求,影响堆芯水位测量的准确性。由于安全壳内环境温度是变化量,导致仪表毛细管内液体重度也随温度的变化而变化,因此不能采用常规仪表恒定密度的迁移方式。对高度差产生的测量偏差进行理论分析,根据分析结果对堆芯水位和参考水位仪表分别采取恒定迁移量和等比例迁移两种迁移方式。经验证结果表明,迁移后的仪表测量的准确性满足设计要求。恒定迁移量和等比例迁移方法能够为其他变量密度的仪表迁移方式提供借鉴。

6000 Type core water level measuring instrument is used to provide reactor water level information to the operator during normal reactor charging and draining, and to monitor reactor core flooding in case of reactor loss of coolant accident to ensure unit safety. The installation height of the positive and negative pressure side of a nuclear power unit 6000 type core water level measuring instrument deviates from the design, resulting in the measurement results not meeting the design requirements and affecting the accuracy of the core water level measurement. Since the ambient temperature inside the containment is a variable quantity, resulting in the liquid weight inside the instrument capillary also changing with the temperature, the migration method of constant density of the conventional instrument cannot be used. The theoretical analysis of the measurement deviation generated by the height difference is carried out, and according to the analysis results, the core water level and reference water level instruments are migrated in two ways: constant migration and equal proportional migration. The accuracy of the instrument measurement is verified to meet the design requirements after migration. The constant and equal proportional migration methods can be used as a reference for the migration of other variable density instruments.