IntroductionShallow machine learning algorithms exhibit low efficiency in fault diagnosis under the conditions of small-sample and unlabeled data. To address this critical problem, this paper focuses on developing an effective fault diagnosis method suitable for cross-reactor-type scenarios, which is of great significance for improving the safety and operational level of nuclear power plants.MethodsA cross-reactor-type fault diagnosis method based on adversarial transfer learning is proposed. By integrating deep learning and transfer learning techniques, a hybrid domain-adversarial learning model is constructed. The overall loss function of the model is designed to effectively extract transferable features between related reactor types, and corresponding validation experiments are carried out to verify the model's feasibility and effectiveness.ResultsThe experimental validation shows that the proposed hybrid domain-adversarial learning model can effectively extract transferable features across different reactor types, which solves the problem of low efficiency of shallow machine learning algorithms in fault diagnosis under small-sample and unlabeled data conditions. The model achieves reliable fault diagnosis performance in cross-reactor-type scenarios.DiscussionWhen applied to cross-reactor-type nuclear power plant fault diagnosis, the research findings can significantly enhance the safety of nuclear power plants, improve their economic performance and operational efficiency. Furthermore, this research effectively promotes the intelligence level and autonomous decision-making capabilities of nuclear power plants, providing a valuable technical reference for the intelligent development of the nuclear power industry.

Acoustic thermometry is widely used in engineering temperature monitoring, but sparse acoustic rays caused by constrained transducer deployment hinder its high-precision upgrade. This study aims to address the core challenge of high-fidelity temperature field reconstruction under sparse measurement conditions. A novel method integrating sparse dictionary learning and physical constraints is proposed: the sparse dictionary captures spatial structural priors of temperature fields, while physical governing equations embed temporal evolution laws, jointly breaking through data dimensionality limitations. Simulation and practical verification (nuclear power plant eight-channel ultrasonic device) show that the method achieves excellent spatiotemporal consistency, accurately reproducing time-varying temperature field evolution; validated with actual nuclear power plant data, the proposed method improves the accuracy of the output average temperature by 2-7 K compared with existing methods. This work provides a new technical approach for high-precision temperature measurement under sparse conditions, enhancing thermal parameter safety monitoring in complex engineering scenarios.

Acoustic tomography (AT) is a non-contact technique for reconstructing internal temperature distributions from the relationship between sound velocity and temperature. However, conventional static reconstruction methods based on synchronous sampling suffer from the failure of the “frozen field” assumption in unsteady temperature fields and cannot adequately handle the spatiotemporal asynchrony of multipath signals. To address this problem, this paper proposes a spatial-feature-learning-based reconstruction framework for dynamic temperature fields. The method organizes transit-time data into tensor form, models acoustic propagation paths using graph structures, and employs non-negative matrix factorization to decouple spatiotemporal features. A graph-specific spatial-basis learning mechanism is further introduced to extract reusable low-rank features under fixed transducer layout and fixed path correspondence, enabling frozen reuse across unseen temperature-field backgrounds within the same graph structure. Numerical simulations show stable reconstruction performance across multiple dynamic moments, with overall temperature-field errors maintained within 2%–4%. In a field case using three valid TOF frames from the Chongqing Qineng Power Plant boiler furnace, the thermocouple references were located 500 mm below the acoustic measurement plane. The paired field-test records indicated an apparent non-coplanar reference discrepancy of 0.86% ± 0.16%. Under this limited reference configuration, the proposed method produced physically plausible temperature fields and lower RMS discrepancies than comparison methods, supporting preliminary engineering feasibility rather than strict full-field accuracy validation.

Measurement of Water Level of Pressure Vessel is important for Accident Management of Nuclear Power Plant. The thermal diffusion water level detector has the characteristics of structural node, high reliability, high temperature and high radiation environment resistance. But it has the problems of high power waste and long response time. By creating a new heater structure，new measurement point structure and a automatic calculating method, the Response-Time of detector has been improved to less the 15 s in limited power. The function and reliability of the detector has proved by experimentation.

Research on virtual measurement of key parameters in reactors can achieve diversified measurements, which is beneficial for improving the reliability and accuracy of measurements. Due to the weak correlation between reactor parameters, meeting the sparsity requirements, and the strong interpretability of sparse reconstruction methods, research on virtual measurement of key reactor parameters based on sparse reconstruction is conducted. Taking the steam generator water level as an example, data is generated based on simulation software. Through data correlation analysis, measurement model construction and solving, the sparse vector of the measurement parameter model is obtained, the virtual measurement of the steam generator water level is realized. The accuracy of the sparse reconstruction method is proved to be high through validation with simulation data and real data, verifying the feasibility of the method.

Turbulent coolant flow in a nuclear reactor's primary loop leads to temperature non-uniformity in the heat pipe section. Utilizing sound wave temperature measurement techniques mitigates calculation errors caused by temperature variations. However, complex temperature-velocity coupling induces significant bending of sound wave paths, affecting measurement accuracy. This study proposes a triangular ray tracing method to accurately track sound wave paths considering coolant temperature gradients and flow dynamics. Experimental validation using finite element simulation data from the Hua-long Pressurized Reactor primary loop demonstrates improved reconstruction accuracy by up to 0.59% compared to straight lines and by up to 0.04% compared to other ray tracing methods.

The digitization of nuclear power plants has become an inevitable trend in the future development of the nuclear energy industry. Based on the engineering application of Engineering Base software platform, this paper proposes principles and requirements for logic modeling of digital instrumentation and control (I C) systems, modeling processes, model verification and release procedures, and other content elements. This research provides a reference for logic modeling of I C systems in digital nuclear power plants, promotes the digital transformation of design aspects such as functional logic and termination logic in nuclear power plant I C systems, and enhances design efficiency while reducing design errors.

The liquid level measurement for high-temperature and high-pressure vessels in nuclear power plants (such as pressurizers and steam generators) all adopts the pressure principle. Affected by the state of the medium inside the vessels and the operating conditions of the system, differential pressure liquid level measurement suffers from issues of low accuracy and poor reliability. Radar level meters, featuring high precision and reliability, represent an effective means for liquid level measurement in high-temperature and high-pressure vessels. In view of this, a split-type guided-wave radar with FMCW (Frequency Modulated Continuous Wave) modulation based on the Frequency Domain Reflectometry (FDR) principle is proposed for liquid level measurement. This technology can effectively eliminate the influence of obstacles such as heating elements, reference tube water supply devices, and reference tube nozzles inside the vessels, achieving blind-zone-free liquid level measurement and meeting the liquid level measurement requirements for high-temperature and high-pressure vessels in nuclear power plants.

In the one-loop pipeline of a nuclear reactor, when measuring fluid flow velocity using ultrasonic transducers based on the time-of-flight method, the acoustic wave trajectory shift leads to a time lag in the receiver's response to the acoustic pressure signal, introducing errors in fluid velocity measurements. To enhance measurement precision, this paper integrates information on the flow and temperature fields within the one-loop pipeline, analyzing the impact of three-field coupling on ultrasonic characteristics. The acoustic field within the pipeline is simulated and modeled, and the mathematical model of the Gaussian beam method is further refined to accurately analyze the propagation trajectory of ultrasonic sound lines and the distribution of acoustic pressure in the pipeline. Finally, the applicability of the established Gaussian beam method is validated by comparing finite element method simulations with mathematical model calculations. Additionally, a comparison is made between the results of the Gaussian beam method before and after improvement when applied to flow measurements on the first loop pipe of "Hualong-1" The findings indicate a reduction of approximately 20 % in the calculation error of ray trajectory offset, about 1 % in the calculation error of flow measurements, and the error in the sound pressure calculation at the transducer axis is within 5%, and the error in the sound pressure calculation at the receiver transducer is reduced by 2 %.

The acoustic tomography (AT) velocity field reconstruction technique has become a research hotspot in recent years due to its noninvasive nature, high accuracy, and real-time measurement advantages. However, most of the existing studies are limited to the reconstruction of the velocity field in a rectangular area, and there are very few studies on a circular area, mainly because the layout of acoustic transducers, selection of acoustic paths, and division of measured regions are more difficult in a circular area than in a rectangular area. Therefore, based on AT and using the reconstruction algorithm of the Markov function and singular value decomposition (MK-SVD), this paper proposes a measured regional division optimization algorithm for velocity field reconstruction in a circular area. First, an acoustic path distribution based on the multipath effect is designed to solve the problem of the limited emission angle of the acoustic transducer. On this basis, this paper proposes an adaptive optimization algorithm for measurement area division based on multiple sub-objectives. The steps are as follows: first, two optimization objectives, the condition number of coefficient matrix and the uniformity of acoustic path distribution, were designed. Then, the weights of each sub-objective are calculated using the coefficient of variation (CV). Finally, the measured regional division is optimized based on particle swarm optimization (PSO). The reconstruction effect of the algorithm and the anti-interference ability are verified through the reconstruction experiments of the model velocity field and the simulated velocity field.

The temperature and flow rate of coolant in the hot legs of pressurized water reactor(PWR)systems directly reflect the nu-clear power and the heat transfer state of the reactor core,and are key parameters for reactor power control and safety protection.In order to comprehensively understand the distribution and evolution of the coolant flow-thermal coupling field in the upper plenum and hot leg of the Hualong One,and provide references for the measurement and control of core parameters,FEA(finite element analysis)method was employed in this paper to conduct CFD(computational fluid dynamics)numerical simulations of the coolant flow region in the upper ple-num and hot legs.Firstly,a reasonably simplified 3D geometrical model of the upper plenum and hot legs of the Hualong One was estab-lished.Subsequently,the computational domain of the model was discretized into meshes and a mesh sensitivity analysis was performed.Fi-nally,through calculations,a steady-state solution of non-isothermal coolant flow was obtained,with relative errors between flow rate,tem-perature and related design estimates and actual measured values all less than 2％.Analysis of the steady-state characteristics indicates that an uneven coolant temperature distribution at the inlet of the hot legs is caused by insufficient heat exchange between high and low tempera-ture coolants near the vertical inner wall of the upper plenum,with a temperature difference between 14.0 ℃ and 16.3 ℃.As the coolant flows along the axial direction,both the temperature and flow distribution gradually become uniform and stable.Furthermore,the variation of the coolant temperature distribution is dominated by the flow of the low temperature coolant inside the hot legs.

Wireless temperature and pressure sensors are miniaturized, integrated design, in order to meet the irradiation index of 1000 Gy in the nuclear environment, for the γ-ray energy and penetration of the characteristics of the large and very strong, the shielding structure of the whole package, that is, in addition to the sensor sensitive components, the signal conditioning circuits, wireless transceiver circuits, power supply circuits, and other modules are used in a full range of high-density materials to wrap. Among them, the power supply part is powered by lithium battery, which occupies a larger volume and has a larger cost of anti-irradiation shielding. In this paper, the radiation resistance of lithium battery is analyzed and verified by test. According to the test results, after the cumulative irradiation of 1198 Gy, the voltage change of lithium battery before irradiation decreases by 0.05 V at maximum, and the rate of change is 1.3

温度是核电厂安全运行的重要参数.对全光纤式的光纤珐珀温度传感器开展了研究.在单模光纤端面熔接一段带有空气腔的多模光纤.多模光纤部分构成珐珀干涉腔,利用多模光纤形成的珐珀腔感温.在热光效应和热膨胀效应下,温度的变化引起珐珀腔中光程差的改变.试验结果表明,50℃下腔长为592.0 μm的光纤珐珀温度传感器,在50～200℃温度范围下的温度灵敏度为0.018 11 μm/℃、线性度为0.993 65.通过分析讨论,提出了两种进一步提高光纤珐珀温度灵敏度的方法.这种全光纤式的光纤温度传感器相对毛细管式光纤珐珀温度传感器具有体积更小、结构更简单的优势,在恶劣及空间狭小的环境有广阔的应用前景.

At present, the water levels of high-temperature and high-pressure vessels such as voltage stabilizers and steam generators on ships' nuclear power plants are measured by the pressure principle. Affected by the load conditions in the vessels, the differential pressure water level measurement has problems of low accuracy and low reliability. The radar type liquid level gauge has the advantages of high precision and high reliability, and is an effective means of measuring the liquid level of high temperature and high pressure containers. In this paper, a FMCW system split guided wave radar based on the principle of frequency domain reflection (FDR) is proposed for liquid level measurement. The antenna probe part and the electronics part adopt a split structure, and the electronics part is installed in the secondary instrument cabin with better environmental conditions., the radar is easy to meet the index requirements of shock, vibration and irradiation. The high-frequency signal emitted by the radar antenna is conducted along the coaxial rod probe, and the signal will be reflected only when it encounters the surface of the material, which effectively eliminates the influence of obstacles such as the heating plate in the container, the internal reference pipe water replenishment device and the reference pipe connection. Non-blind zone measurement of liquid level to meet the liquid level measurement requirements of high temperature and high pressure vessels in ship nuclear power plants.

核电厂中广泛存在的传感器为其运行提供了重要支持.传感器的任何故障都可能威胁到核电厂的安全.为提升核电厂运行可靠性,提出结合残差双向长短期记忆(ResBiLSTM)神经网络和稀疏注意力机制的传感器故障诊断方法.以核电厂目标传感器和与之紧密相关的敏感参数集时序信号作为输入,构建ResBiLSTM模块进行故障特征提取.将残差模块的输出送给稀疏注意力模块,进一步关注历史序列时刻中的重要部分.筛选保留目标特征,滤除冗杂特征,以实现精准提取有效故障特征.在输出端,利用Softmax分类器输出故障分类结果.对核电厂反应堆出口温度现场数据进行故障注入以及诊断试验,故障识别准确率均达到98％以上.试验结果表明,所构建模型可以实现对原始时域信号的多尺度特征提取和故障诊断.通过与深度卷积神经网络(CNN)、深度稀疏自编码器(SAE)和支持向量机(SVM)等算法进行对比,所提模型的故障识别性能更优.

The application of wireless sensor network in nuclear power plant can greatly reduce the workload of nuclear power plant cable wiring, and help to improve the automation and information level of nuclear power plant. However, its application also faces the constraints of strong electromagnetic interference, high temperature and other special complex nuclear environment, especially the narrow multi metal enclosed space of nuclear power plant cabin, which brings challenges to the application of wireless sensor. Based on the Lora wireless protocol, this paper studies the low-power selection of wireless sensor and MCU, sleep / wake-up low-power mechanism, dual star adaptive frequency hopping anti-interference, frequency division and time division multi node real-time communication and other aspects. On this basis, the prototype is developed, and the functional test, high and low temperature test, electromagnetic compatibility test and bench test are carried out. The feasibility of wireless sensor application in nuclear power plant is preliminarily verified, which lays a foundation for further application.

Nuclear power plants need to transmit a large number of switch signals, while traditional electrical transmission of switch signals requires a large number of cables, which makes it difficult to realize self-inspection of transmission path faults and is vulnerable to electromagnetic interference. In view of the needs of a large number of switch signal transmission and the shortcomings of traditional electrical methods, this paper developed two sets of switch signal transmission systems based on optical fiber, which realized the simultaneous transmission of 16 channels and 2 channels of switch signals on one optical fiber, and had the function of transmission path fault self-checking. It has the advantages of wide frequency response range, small transmission delay, high reliability and strong environmental tolerance, and has broad application prospects.

无线传感器网络作为一种分布式无线网络系统,应用于核环境中,可以减少监测系统电缆布线工作量、降低核环境中装置使用和维护中电缆老化和端接故障带来的影响,有助于核环境中装置自动化、信息化水平的提升和设备的集成化、小型化.但其应用也面临强射线及中子辐照、射频和电磁干扰严重等特殊复杂核环境的制约.针对核环境中的γ辐射,通过屏蔽材料性能分析、蒙特卡罗N粒子程序模拟、屏蔽结构设计及布局,得到了核动力装置中所用无线传感器及网关抗辐射屏蔽加固的合适厚度及整体结构;通过辐照试验,验证了所设计的抗辐照屏蔽体至少能够承受500 Gy的累积辐照剂量.该研究为后续智能仪表的辐照屏蔽设计奠定了设计基础.