AN INTERNATIONAL VIEW OF DIFFERENT APPROACHES FOR FAULTS DETECTION AND IDENTIFICATION IN NUCLEAR POWER PLANTS

An extensive survey of computer based systems that apply different approaches for faults diagnostics and identifications in nuclear power plants (NPPs) was presented. In the light of reviewed material, the classification criteria were developed. The classification of computational techniques (class of computing devices, class of programming languages, and simulation programs) was discussed. The classification of theoretical aspects applied (brief aspects, and detailed aspects) in computer based diagnostic systems were established. The classification of metholology applied (symbolic reasoning methodology, event based methodology, and function based methodology) in the diagnostic systems was also depicted. In the end, the personal comments on the reviewed material, and scope of the study were described.

SRDAAR－QNPP：a computer code system for the real－time dose assessment of an accident release for Qinshan Nuclear Power Plant

The paper presents a computer code system 'SRDAAR- QNPP' for the real-time dose as-sessment of an accident release for Qinshan Nuclear Power Plant. It includes three parts:thereal-time data acquisition system, assessment computer. and the assessment operating code system. InSRDAAR-QNPP, the wind field of the surface and the lower levels are determined hourly by using amass consistent three-dimension diasnosis model with the topographic following coordinate system.A Lagrangin Puff model under changing meteorological condition is adopted for atmosphericdispersion, the correction for dry and wet depositions. physical decay and partial plume penetrationof the top inversion and the deviation of plume axis caused by complex terrain have been taken in-to account. The calculation domain areas include three square grid areas with the sideline 10 km, 40krn and 160 km and a grid interval 0.5 km, 2.0 km, 8.0 km respectively. Three exposure pathwaysare taken into account:the external exposure from immersion cloud and passing puff, the internalexposure from inhalation and the external exposure from contaminated ground. This system is ableto provide the results of concentration and dose distributions within 10 minutes after the data havebeen inputed.

A framework for nuclear power plant emergency response system

The purpose of this study is to establish an intelligent expert system for nuclear power plant emergency response.A new framework of environmental risk management methodology by the concept of pattern recognition was introduced in this paper.A knowledge-based decision support system for emergency response and risk management of nuclear power plant was also discussed.The mathematical pattern relationship of accidental release effects on neighboring area and the corresponding response measures were presented in this paper.With this decision system,the decision maker can specify the procedure and minimize their human error in the decision process.The improvement of risk response and the quality of management system could be upgraded by this system.Besides,the methodology can also be served as a basis for the future development of environmental risk response system design.

Modeling the Effect of Thermal Diffusion Process from Nuclear Power Plants in Vietnam

In this study, we evaluate the ecological impact of effluent cooling water from the Ninh Thuan nuclear power plant II, using a two-dimensional hydraulic model to simulate thermal diffusion from the effluent outfall. Sites selected for this study were Ninh Thuan nuclear power plant and Vinh Hai seawater in four different scenarios. This paper utilized the relationship between surface water temperature and the water temperature at a depth of -15 m to calculate the water temperature at intake and outlet at a depth of -14 m. A combination between the results of interpolated and results of model showed that effluent cooling water from Ninh Thuan plant affected the largest incidence about 2450 m in the North, 880 m in the South and 960 m in the West. It can be considered as safe distance to not to affect the coral reefs ecosystem in the North and sea turtle conservation area in the South. This study was first in this region to have an integrated approach using two-dimensional model.

秦山三期CANDU核电厂的安全系统和安全分析

加拿大ＣＡＮＤＵ 核电厂核反应堆安全原理采用“纵深防御”的概念， 并在设计中采用了多重性、多样性、隔离、设备鉴定、质量保证以及使用合适的设计法规和标准等设计手段。秦山三期ＣＡＮＤＵ 核电厂在缓解事故后果方面设置了四个专设安全系统以及一套可靠的安全支持系统。对这些安全系统性能分析的结果表明： 有关公众剂量， 以及燃料、燃料通道和反应堆厂房等完整性的基本安全准则是满足的。

秦山三期CANDU核电厂的控制系统

秦山三期ＣＡＤＮＵ 核电厂全厂控制系统使用双重冗余数字计算机， 自动完成监测、控制、运行信息管理和诊断等功能。采用多变量数字控制算法实现对反应堆功率、蒸汽发生器液位和压力、热传输系统压力和装量、慢化剂温度、汽轮机负荷和转速、发电机功率输出以及不停堆换料的控制， 保证核电厂安全、经济地运行。

CANDU 6核电站反应堆厂房主设备安装模式

对ＣＡＮＤＵ６反应堆厂房主设备两种不同的安装模式从技术、经济、进度等方面进行了分析比较，说明在秦山三期工程中采用ＬＲ１６５０履带吊车从厂房顶部吊装主设备，技术上操作简便，安全可靠，进度上可缩短工期，经济上也给电站带来可观的效益。

秦山三期CANDU核电厂热传输系统

热传输系统利用高压重水作为工质将大量的热能从堆芯传输到蒸汽发生器， 产生蒸汽去推动汽轮机。为了使热传输系统在电厂动态条件下安全可靠地运行， 需要一些辅助和控制系统的配合。本文介绍正在建设的秦山三期ＣＡＮＤＵ

Short-term emergency response planning and risk assessment via an integrated modeling system for nuclear power plants in complex terrain

Short-term predictions of potential impacts from accidental release of various radionuclides at nuclear power plants are acutely needed, especially after the Fukushima accident in Japan. An integrated modeling system that provides expert services to assess the consequences of accidental or intentional releases of radioactive materials to the atmosphere has received wide attention. These scenarios can be initiated either by accident due to human, software, or mechanical failures, or from intentional acts such as sabotage and radioIogicaI dispersal devices. Stringent action might be required just minutes after the occurrence of accidental or intentional release. To fulfill the basic functions of emergency preparedness and response systems, previous studies seldom consider the suitability of air pollutant dispersion models or the connectivity between source term, disper- sion, and exposure assessment models in a holistic context for decision support. Therefore, the Gaussian plume and puff models, which are only suitable for illustrating neutral air pollutants in fiat terrain conditional to limited meteorological situations, are frequently used to predict the impact from accidental release of industrial sources. In situations with complex terrain or special meteorological conditions, the proposing emergency response actions might be questionable and even intractable to decision- makers responsible for maintaining public health and environmental quality. This study is a preliminary effort to integrate the source term, dispersion, and exposure assessment models into a Spatial Decision Support System （SDSS） to tackle the complex issues for short-term emergency response planning and risk assessment at nuclear power plants. Through a series model screening procedures, we found that the diagnostic （objective） wind field model with the aid of sufficient on-site meteorological monitoring data was the most applicable model to promptly address the trend of local wind field patterns. However, most of the hazardous materials being released into the environment from nuclear power plants are not neutral pollutants, so the particle and multi-segment puff models can be regarded as the most suitable models to incorporate into the output of the diagnostic wind field model in a modern emergency preparedness and response system. The proposed SDSS illustrates the state-of-the-art system design based on the situation of complex terrain in South Taiwan. This system design of SDSS with 3- dimensional animation capability using a tailored source term model in connection with ArcView~ Geographical Information System map layers and remote sensing images is useful for meeting the design goal of nuclear power plants located in complex terrain.

红沿河核电厂地震仪表系统震后数据分析

2023-08-23红沿河核电厂地震仪表系统成功记录到大连市普兰店区发生的4.6级地震,这是我国首次完整记录到核电厂附近中强震数据。对该系统记录到的地震数据进行分析,时程信号波形回放表明,本次地震记录数据清晰完整,自由场数据峰值与地震衰减经验公式计算结果相符。系统7个监测点加速度峰值对比分析表明,核电厂厂房对地震加速度信号具有放大效应,放大系数与建筑物标高正相关。加速度峰值数据频谱分析结果显示,核电厂厂房地震响应数据的卓越频率主要集中在10~20 Hz范围内,该范围内的地震加速度信号对厂房仍具有较大破坏性,这一结论与核电厂地震仪表准则NB/T 20076-2012中规定的地震触发频带(1~10 Hz)不符。鉴于我国核电厂地震仪表系统的地震触发滤波通频带设定范围为1~10 Hz,这一缺陷会降低地震仪表系统纵深安全防御的性能。

基于SOS-LSTM的核电站隐蔽攻击方法研究

针对实现隐蔽攻击需要获取攻击目标高精度估计模型的问题,提出一种基于共生生物搜索算法优化长短期记忆神经网络(SOS-LSTM)的隐蔽攻击方法。首先,将攻击目标的反馈控制器输出和输入信号作为长短期记忆神经网络的数据集,通过训练得到受攻击区域的估计模型,再利用估计模型设计隐蔽攻击器向受攻击对象施加攻击信号。此外,使用SOS算法优化LSTM的网络参数来提升隐蔽攻击器的性能。对核电站一回路控制系统进行隐蔽攻击的仿真实验结果表明,该攻击方法在对目标控制系统输出信号实现预先设定攻击行为的同时具有较高隐蔽性。

基于故障树和产生式规则的故障诊断专家系统设计

[目的]为充分运用核动力装置的运行管理经验辅助核动力操纵人员进行故障诊断,设计一种船用核动力装置故障诊断专家系统。[方法]首先,根据故障树与产生式规则之间的逻辑一致性,提出一种将故障树知识转化为产生式规则的方法;然后,对采用正、反向混合推理方法的专家系统知识库和推理机进行优化设计,并依据故障树最小割集和重要度分析结果设计正向推理策略以简化推理流程;最后,根据人工对故障状态判断的思路设计状态监测模块,实时采集关键设备参数以转化为专家系统可识别的设备信息。[结果]结果显示,采用所提方法可解决专家系统知识获取困难的问题,能在保证推理准确度的前提下提升推理效率,实现了专家系统的在线故障诊断功能。[结论]研究表明采用所提方法可提升专家系统获取知识的能力和推理效率,对保障核动力装置的运行管理安全具有重要意义。

核电厂便携式低放废水在线监测设备关键技术探讨

结合核电厂的实际情况和需求,梳理了低放废水的特点,明确了其对便携式在线监测设备的技术要求,其中最关键是能同时满足低探测下限(MDAC≤8 Bq/L)和便携性(设备总重≤50 kg)的限制。讨论了测量方式、探测器选型和校准方式等在线监测设备的关键技术,对低放废水进行了放射性在线监测,测量方式选择取样式,探测器选择大体积NaI晶体,校准方式选择代表点法。调研了低放废水在线监测设备的研究现状,现有的在线监测设备重量都在200 kg以上,与核电厂的要求之间存在较大的差距,有必要开展同时具备低探测下限和优异便携性的新型在线监测设备的研制。对新型探测器的应用、结构和新型测量方式的发展这三个研究方向给出了建议。最后,从提高探测效率的角度,提出了一种基于环形NaI晶体的新型探测器结构,初步论证了其探测下限和设备总重指标有望满足核电厂的要求。

核电厂安全级DCS缺省值设置策略研究

针对数字化仪控系统中无效信号的质量位随意蔓延使系统处于一种不确定状态的问题,结合核电厂运行工况和信号特性,对龙鳞平台故障诊断机制和信号质量位标识进行研究。考虑故障安全准则,系统性地提出缺省值设置原则。从信号执行功能和信号边界两个维度进行分析,确认缺省值的设置范围,并详细给出执行保护功能、报警功能、维护和试验功能信号的缺省值设置策略。同时,针对传统的缺省值验证方式无法全面、有效地进行缺省值验证的问题,提出一种利用全范围模拟机和虚拟数字化控制系统(DCS)进行缺省值验证的新方法。利用该方法可有效地对DCS内设置的缺省值进行系统性的验证。所提出的缺省值设置策略和验证方法可为后续核电厂安全级DCS的缺省值分析和设置提供全面的指导。

土耳其M_(w)7.8地震工业厂房及设施震害调查与分析

2023年2月6日,土耳其卡赫拉曼马拉什省在短时间内相继发生M_(w)7.8和M_(w)7.5地震。与以往地震相比,此次地震具有强度高、双主震的特点,造成了严重的灾害。地震发生后,通过资料收集、对地震中受损的工业厂房及设施进行现场震害调查,探讨了本次地震的地震动特征,比较了土耳其典型强震台站记录到的地震动加速度响应谱与我国规范谱的差异;总结了该地区典型工业厂房及设施的震害特征,并对其破坏原因进行了分析;选取土耳其典型强震台站记录到的地震波,对某核电厂耦合体系进行了单向地震作用计算,探讨了核电厂耦合体系在强震作用下的响应特征。现场调查结果表明:此次土耳其地震的强度远超我国规范的最高标准,且竖向地震动强度显著;一系列高强度地震造成灾区工业厂房及设施受损严重,厂房主体结构发生了严重的倒塌破坏,厂房中的非结构构件和生产设备也遭到了较为严重的破坏,其中非结构构件的破坏以墙体倒塌和吊顶掉落为主。核电厂房耦合体系计算结果表明,在土耳其强震作用下,核电厂内蒸汽发生器的响应大于其抗震能力中值,主管道应力响应大于其允许应力值。调查证明,工业厂房及设施的抗震薄弱环节在于厂房内部设施和设备,完善工业厂房及设施的抗震措施,提升工业设备的抗震能力,是提高工业厂房及设施抗震韧性的有效举措。

核电全厂通信系统设备采购管理浅析

核电站全厂通信系统具有种类繁多、数量多、覆盖全厂等特点。目前,通信设备采购在设计、采购、安装单位管理3个方面均存在较多问题,此类问题制约工程进展。针对上述问题,论文从设计、采购、安装管理3个方面提出了工作对策,旨在提高采购工作效率,保证设备按时到货,保障现场安装进度。

核电厂高压蒸汽管道焊缝切割装置的研制

为了修复某核电厂GPV高压缸排汽管膨胀节导流筒焊缝因热处理不当导致的开裂,研发了一款焊缝切割装置,用于将开裂的焊缝切除并加工坡口以进行下一步的自动焊接修复。首先利用SolidWorks对焊缝切割设备进行了机械设计并三维建模,对驱动电机进行了选型计算,设计了控制系统架构,随后制作了设备样机和膨胀节导流筒模拟体,最后在试验室利用模拟体对设备样机的性能进行了连续切削试验,验证了该装备能够高效完成膨胀节导流筒开裂焊缝的切除和坡口加工,且坡口加工质量优良,装置性能稳定。

基于PLC的核电站一回路水化学监测自动取样系统设计

为了及时、便捷、无污染地获取核电站一回路水质样品,提高水质监测效率,设计了基于PLC的核电站一回路水化学监测自动取样系统。首先对自动取样系统工艺组成进行分析,提出功能需求,设计由现场层、过程层和管理层构成的总体方案,然后介绍各层级硬件组成以及层级间的连接关系,最后,设计过程层PLC的软件程序实现自动取样系统热工参数的实时测量、自动控制和超限保护,设计管理层工业控制计算机人机界面实现参数可视化、存储和报警提示。采用经典的PID算法实现热工参数自动控制,通过理论建模与经验试凑相结合的方式提升PID参数调试效率,并进行手自动无扰切换处理提升自动控制算法的稳定性。经验证,该系统可以稳定、自动获取样品,对提高核电站一回路水化学监测自动化水平有重要意义。

基于相变蓄冷的核电厂主控室非能动冷却系统

为提高现有核电厂主控室紧急可居留系统的蓄冷能力及热舒适性水平,提出了基于定形相变蓄冷材料的核电厂主控室非能动冷却系统。基于主控室热负荷分布情况,该冷却系统在主控室顶板与吊顶之间、内墙面、地板底面及循环风道内,针对性地布置相应的含有定形相变材料的非能动冷却装置,进而实现事故工况下对主控室温度的精确控制。该非能动冷却系统无需引入额外冷源和管道,可靠性强,同时不破坏主体结构,且可灵活布置,解决了现有主控室非能动热阱时间余量小、热舒适性差的问题。