压水堆蒸汽发生器传热管结构状态监测关键技术研究

Flow-induced vibration tests on the steam generator, which realizes the structural health monitoring of heat pipes, could help modify the calculation model, achieve a more accurate prediction on the heat pipe life, and help further optimize the structural design. The key point of monitoring the structural health of the heat pipes is to conduct multi-parameters measurements on the pipes employing force, strain, acceleration or pulsation pressure sensors. However, existing sensors are not able to meet the measuring requirements due to their low working temperature and poor environmental adaptation. Targeting this problem, based on the principles of white - light interferometric fiber optic sensing, this proposal presents the design of the fiber optic force, strain, acceleration and dynamic pressure sensors with good high-temperature and high-pressure performance. In this project, the opto-mechanical properties and characteristic parameters would be investigated; the temperature compensating method would be studied; the temperature- and pressure- proof package technology would be applied in the sensor fabrication process; the calibration of the sensors would be studied, and the static/dynamic calibration and performance tests would be accomplished. On this basis, this program plans to develop a multi-channel high speed optical fiber sensor demodulation system according to the characteristics of our newly-designed fiber optic sensors. The high-precision and high-speed demodulation system aims at a sampling frequency of 10 kHz and a demodulation accuracy of 0.1%FS. The sensors and the corresponding demodulation system will be validated in a full-size and full-flow steam generator test loop.This project is expected to provide a new monitoring method to the structural health condition of the heat pipes in the pressurized water reactor steam generator.

进行蒸汽发生器流致振动试验，实现对传热管结构状态的监测，能够对模型计算进行校正，提高传热管寿命预测准确度，优化其结构设计。传热管结构状态监测的关键是利用力/应变/加速度/脉动压力传感器对传热管进行多参数测量，现有传感器因工作温度和环境适应性无法满足测试要求。针对这一问题，本项目拟基于白光干涉型光纤法珀传感原理设计耐高温、高压光纤力/应变/加速度/脉动压力传感器，研究传感器的光机特性及特征参数；研究传感器的温度补偿方法；研究传感器的耐高温、高压封装技术，并最终加工出传感器；研究传感器的标定方法，完成传感器的静态/动态标定和性能测试。在此基础上，本项目拟根据新设计的光纤传感器特征，设计多通道高速光纤传感器解调系统，实现采样频率10KHz、解调精度0.1%FS的高精度、高速解调；并在蒸汽发生器全尺寸全流量模拟回路开展验证实验。研究成果可为压水堆蒸汽发生器传热管结构状态监测提供一种新的监测方法。

利用力/应变/加速度/脉动压力传感器对蒸汽发生器传热管进行流致振动条件下的多参数测量，可以准确获悉传热管微动状态，预测其使用寿命，有利于优化蒸汽发生器设计，进而提高压水堆安全系数，具有重要意义。本课题成功研制了基于光纤法珀的力/应变/加速度/脉动压力传感器传感器及其解调系统，解决了常规电类传感器在高温、高压及流体条件测量失效的问题。建立了力/应变/加速度/脉动压力传感器的光机耦合模型，设计了传感器的封装结构，完成了耐高温高压防水关键封装工艺研究，实现了传感器的耐高温、高压封装，研制了传感器环境测试平台，实现了传感器在高温高压流体环境下的环境测试；突破现有光纤法珀解调系统性能限制，实现了高精度、高速解调的解调系统；该系统性能为：传感器可以稳定工作在350℃，20MPa的液体环境；力传感器的量程为0-1000N，测量精度为1N；应变传感器的量程为±3000με，测量精度为3με；脉动压力的量程为±100kPa@17Mpa，测量精度为0.5kPa；加速度传感器的量程为0-100g@5Khz；光纤法珀解调仪采样频率达到10kHz。合作单位中国核动力研究设计院反应堆工程研究所利用该系统在蒸汽发生器全尺寸全流量模拟回路上进行了流致振动实验，获取了传热管的力/应变/加速度/脉动压力信号，对于分析和研究传热管的失效具有重要的价值。该系统的成功研制和使用，证明了光纤法珀传感系统在核电应用领域具有较强的应用前景，能够解决传统传感系统不能够解决的关键检测问题，为核电站的安全运行提供技术支撑。