燃料组件的几何结构和栅格参数显著影响铅铋反应堆的物理/热工特性，采用不同几何结构燃料组件的堆芯在相同换料周期、热工限值约束下的临界尺寸、燃料装载量存在差异。本文开展小型轻量化铅铋反应堆的燃料组件几何结构研究，通过建立铅铋反应堆堆芯模型，选取棒束型、环形、蜂窝煤型燃料组件方案，比较分析了3种方案在堆芯尺寸、燃料装载量、冷却剂流通面积、包壳和气隙体积相同和在换料周期为10 a、稳态热工安全裕量基本一致条件下堆芯的燃耗特性、反应性系数、稳态热工特性参数。结果表明：相比于棒束型与环形燃料组件，蜂窝煤型燃料组件良好的稳态热工特性与较硬的中子能谱，采用蜂窝煤型燃料组件的堆芯可以实现更小的堆芯尺寸及燃料装载量，具备显著的膨胀负反馈，同时能够有效展平功率分布和降低堆芯压降，是有利于铅铋反应堆小型化及轻量化的燃料组件方案。

铅铋反应堆广泛应用的需求要求研究人员在现有堆芯方案的基础上开展大量优化设计工作。针对铅铋反应堆多物理、多变量、多约束耦合影响的多维非线性约束优化设计问题，基于Kriging代理模型、正交拉丁超立方抽样和SEUMRE空间搜索技术构建铅铋反应堆智能优化方法，耦合物理蒙卡计算/热工分析程序，开发包含抽样、耦合程序前后处理、反应堆优化分析功能的优化平台，并以铅铋反应堆SPALLER-4，URANUS为原型分别开展最小燃料装载量的方案寻优与参数优化验证。验证结果表明，该智能优化方法用于铅铋反应堆设计方案寻优和堆芯参数优化可行、有效，相比传统蒙卡程序计算寻优，在保证预测精度前提下极大地降低了计算成本，与URANUS初始模型比较，燃料装载量、堆芯总质量、活性区体积、堆芯总体积分别优化10.8%，11.5%，18.1%，17.1%，为基于代理模型的智能优化方法应用于铅铋反应堆的优化设计提供参考。

We propose a new non-intrusive flow measurement method using the distributed feedback fiber laser (DFB-FL) as a sensor to monitor flow in the pipe. The relationship between the wavelength of the DFB-FL and the liquid flow rate in the pipeline is derived. Under the guidance of this theory, the design and test of the flow sensor is completed. The response curve is relatively flat in the frequency range of 10 Hz to 500 Hz, and the response of the flow sensor has high linearity. The flow from 0.6 m³/h to 25.5 m³/h is accurately measured under the energy analysis method in different frequency intervals. A minimum flow rate of 0.046 m/s is achieved. The experimental results demonstrate the feasibility of the new non-intrusive flow measurement method based on the DFB-FL and accurate measurement of small flow rates.

A fiber Bragg grating (FBG) and Fabry–Perot (FP) cavity cascaded fiber sensing system was manufactured for temperature and pressure sensing. Temperature sensing as high as 175°C was performed by an FBG for the linear variation of an FBG wavelength with temperature. After the temperature was sensed, the demodulation system can find the original FP cavity length and its pressure and cavity length correlation coefficient; thus, the ambient pressure would be calculated. The sensing pressure can be as high as 100 MPa with a repeatability of 1/10,000 and high stability. This kind of fiber sensor has been used in the Shengli Oil Field.

We present a high-sensitivity fiber Bragg grating (FBG)-based microphone with a flat response and static pressure equalization. A very high dynamic sensitivity of the microphone is achieved by a pressure sensing structure based on a carbon fiber diaphragm. Static pressure equalization is realized by a balance structure with a capillary glass tube. The resonances of the sensor are suppressed by air damping structures, and a broadened flat response is achieved. An acoustic-solid interaction model was used to analyze the response characteristics of the microphone. An experimental prototype was produced and tested, and the results are well consistent with the design. The tested sensitivity was 10 dB re 1 pm/Pa from 10 Hz to 2.5 kHz with a fluctuation of less than ±1.5 dB. Combined with the phase-generated-carrier-based coherent detection scheme, the microphone can achieve a sound resolution of the milli-pascal level. The static pressure sensitivity is measured to be 0.27 pm/atm, which is 100 dB lower than the dynamic sensitivity.