核电工程建设中焊接及热处理温度对混凝土的影响

文章通过系统梳理和总结AP1000三门和海阳4个核电机组施工中,由于施工逻辑要求、设计制约和设计修改等因素,导致某些部件安装时需要考虑焊接和热处理热量对混凝土影响的案例和控制方法,为后续机组和项目提供了理论和实践经验。文章案例基本覆盖了AP1000施工中遇到的此类问题,并通过施工质量和过程数据得到了验证。     

含铀褐煤综合利用的研究

本文是研究从含铀褐煤中直接提取铀和锗的工作报告。给出了用硫酸和硝酸方法浸取的条件和结果。重点讨论了用硫化钠溶液和清水分步浸取原煤中的锗和铀及用丹宁沉淀浸出液中锗的条件。铀的浸出率和沉淀率分别为76%和98%;锗的浸出率和沉淀率分别为80%和98—100%。分析了控制锗的浸出率的因素,提出了从研究浸取过程的化学机理和过程机理出发,进一步寻求提高铀、锗浸出率和降低试剂消耗的方向。     

核电厂安装和调试期间设备和系统的维护保养

研究了核电厂安装和调试期间开展设备和系统专业维护保养的必要性,讨论了如何组织核电厂安装和调试期间的设备和系统维护保养,并根据核电厂的特点给出核电厂安装和调试期间设备和系统维护保养技术管理的建议,以保证核电厂投入运行后设备和系统能保持较高的可利用率.     

人工智能和大数据在核电领域的应用研究

人工智能和大数据技术是目前国内外各个领域的研究热点。本文基于人工智能和大数据技术,探讨其在核电领域的应用。首先,在阐述人工智能和大数据技术对于核电发展的重要意义基础上,总结人工智能和大数据技术目前在国内外核电领域的应用现状;然后分析人工智能和大数据技术在核电领域应用的建设思路和内容;其次,明确人工智能和大数据在核电领域应用的关键技术和核心应用,最后从战略角度提出支持人工智能和大数据技术在核电领域应用和发展的建议。     

核电厂流出物中14C的管理控制

介绍了国内外压水堆(PWR)和重水堆(HWR)核电厂流出物中14C的产生和释放管理现状、减少14C产生和释放的方法以及14C的提取、净化和分析方法,为我国核电厂气态和液态流出物中14C的监测和控制提供基础资料.此外,针对我国核电厂14C的排放和监测情况,提出了几点建议.     

水和蒸汽的体膨胀系数和压缩率

水和蒸汽的体膨胀系数和压缩率是反应堆热工水力、传热学和工程热力学中常用的参数之一。这两个参数的计算公式是Gibbs折合自由焓和Helmholtz折合自由能的导出函数。水和蒸汽的体膨胀系数和压缩率的提出,解决了传热学、工程热力学和核反应堆热工水力学的实际应用问题。在反应堆热工水力设计中,可以直接利用这两个参数来求解流体的温度和压力,比反复利用质量、能量和动量方程求解流体的温度和压力大大节省计算时间和     

概率安全分析软件的自主化研究与设计

随着核电技术和核电工程的快速发展,组织力量进行适用于Living PSA分析和应用开发要求的PSA计算分析软件的自主开发变得十分必要和迫切。核电站快速风险分析软件NFRisk的研究和开发着眼于研究Living PSA的管理和技术要求,基于这些要求开发PSA模型开发和维护的计算机程序,实现故障树建立和分析、不可用度分析、重要度分析、敏感性分析和时间相关性分析,以及事件树建立和分析等功能,并具备能够对大型PSA故障树进行快速分析和定量化的能力;同时NFRisk软件还将包括数据库分析和管理程序包,与目前商用PSA软件的数据接口程序等,最终构建成一个可进行多种应用开发的NFRisk软件。本文主要介绍NFRisk软件的开发设想、方案设计以及主要功能。     

核电厂老化和寿命管理现状与进展

探讨了国内外核电厂老化和寿命管理方法、法规和实践。总体来说,IAEA的法规和导则指导性强,美国的法规和实践可操作性强,法国的法规和实践则较为系统化和标准化。针对这些特点,结合我国老化管理现状,给出了我国在进行核电厂老化和寿命管理实践以及建立相应的法规导则体系时应注意的问题。     

核电产业的国产化和自主化

描述我国必须积极发展核电，解决能源短缺问题。核电国产化和自主化是发展核电的关键，自主化和国产化的核电技术才具备竞争实力，中国具备核电产业国产化和自主化的条件和能力。技术的引进、消化和吸收可以提高我国核电研发能力，加速我国核电产业的自主化和国产化进程。     

压水堆主回路失水事故下水锤与管道结构的相互作用分析

传统的水锤分析和管道动力响应计算是分开的，存在一定的缺陷。本文针对核电站主回路假想双端断裂时系统的受力和力矩分析这一问题，对破裂管道分充体和管道的耦合机制，引入描述流体－管道单元的１４个参数和１４个偏微分方程，利用特征线法对水锤和管道结构的相互耦合作用进行了模拟计算。计算得到了更为准确的水锤波和管道的受力和力矩，其波形和数值均与不考虑耦合作用时有所不同。这些计算结果为压水堆核电站的核安全设计和分析     

油田水力压裂裂缝的放射性示踪实验研究

针对目前油田主要的增产措施--水力压裂的效果进行评价，使用放射性示踪技术，对压裂裂缝进行示踪实验研究。首先制备了三种示踪砂，在压裂过程中注入到裂缝中，再经过能谱测井，跟踪地层中示踪砂能区伽玛计数率的变化，可以直观清晰的确定裂缝的深度和高度，清楚的判断裂缝是否处于压裂目标地层，实验过程中使用三种示踪砂跟踪压裂过程，反映裂缝是否在压裂过程中持续发育，进而评价压裂效果。研究结果表明，压裂裂缝放射性示踪可以完善裂缝参数，为压后评价和相同油区块压裂施工设计提供有效依据。     

On the systematic evaluation of the fracture safety,particularly for pressure vessels

A systematic evaluation of the fracture safety particularly for pressure vessels is presented. It is a stepwise approach based on the conventional brittle fracture test methods (qualitative assessment using temperature criteria) as well as on the current fracture mechanics test methods (quantitative assessment using LEFM-EPFM). The important aspects in connection with the application of the quantitative assessment, e.g. material and fracture mechanics properties, specimen types, test and fracture mechanics analysis methods are discussed. Also results of a fracture mechanics test program for a reactor pressure vessel are shown and the importance and the difficulties to acquire component specific fracture mechanics properties are described.     

高放废物处置库近场裂隙水流-传热-处置室间距相互作用的三维数值分析

为研究高放废物地质处置库近场裂隙水流-传热-处置室间距的相互作用机理,采用3DEC软件计算裂隙水流-传热-处置室间距相互作用对处置库近场温度分布影响。结果表明:(1)在处置室间距相同条件下,流动的裂隙水显著改变了处置库近场温度场,使岩体温度降低,缩短模型达到稳态所需要的时间。(2)处置室间距增大,温度叠加效应减弱,处置库近场温度越低,并且废物罐表面膨润土温度越低,裂隙出水口水温越低,模型达到稳态所需要的时间越短。(3)水平和垂直裂隙水流共同传热使处置库近场裂隙水流下游区域温度显著高于裂隙水流上游区域。(4)处置室间距为6 m和8 m时,水平裂隙出水口水温高于垂直裂隙,处置室间距为10 m时,水平裂隙出水口水温低于垂直裂隙。     

基于主曲线法的核电主管道材料断裂韧性研究

核电工程的防脆断设计和在役缺陷评价主要应用线弹性断裂力学，并基于材料断裂韧性进行评价。材料断裂韧性需通过试验测定，首先采用落锤试验和V型缺口冲击试验共同确定参考温度，或采用主曲线法确定参考温度，然后将参考温度和材料温度作为变量建立关系式描述材料的断裂韧性。主曲线法能通过较少的试样试验得到材料的断裂韧性，并具有较高的置信度，因此在工程中已得到越来越多的应用。文中采用ASTM E1921标准，应用主曲线法测量了某核电厂主管道材料的参考温度，确定了材料的断裂韧性，并与ASME第Ⅺ卷附录G中的断裂韧性进行比较。结果表明，采用主曲线法得到的材料断裂韧性更高，工程应用中减少了保守裕度，提高了经济性。     

Study on Fracture Toughness of Nuclear Power Main Pipeline Material Based on Master Curve Method

The design against brittle fracture and in-service defect evaluation of nuclear power engineering mainly use linear elastic fracture mechanics, and the evaluation is based on the fracture toughness of the material. The fracture toughness of the material needs to be determined by testing. First, the reference temperature is determined by the drop weight test and the V-notch impact test, or by master curve method, then the reference temperature and the material temperature are used as variables to establish a relationship to describe the fracture toughness of the material. The master curve method can obtain fracture toughness through the fewer sample tests and the higher confidence, so it has been used more and more in engineering. In this paper, the ASTM E1921 standard was used to measure the reference temperature of the main pipeline material of a nuclear power plant using the master curve method. The fracture toughness of the material was determined, and compared with the fracture toughness in Appendix G of ASME Volume Ⅺ. The results show that the fracture toughness of material obtained by the master curve method has higher value, and the conservative margin is reduced in engineering, so economy is improved.     

Analysis of cleavage fracture potential of martensitic stainless steel fusion structures: Part I. Micromechanical models and material properties

The major disadvantage of martensitic stainless steels for structural applications in fusion reactors is currently considered to be their potential for low temperature brittle cleavage fracture. This study attempts to review the current understanding of cleavage fracture in steels and the role of microstructure in dictating material resistance to this type of fracture. A parametric analysis of cleavage fracture in a surrogate steel, A533B, is made and the results are used in conjunction with general cleavage fracture theory to establish some potential guidelines for future research in developing the martensitic stainless steels.     

Fracture toughness of China low activation martensitic (CLAM) steel at room temperature

The fracture toughness (J_IC) of China low activation martensitic (CLAM) steel was tested at room temperature through the compact tension specimen, the result is 417.9 kJ/m², which is similar to the JLF-1 at same experimental conditions. The microstructural observation of the fracture surface shows that the fracture mode is a typical ductile fracture. Meanwhile, the fracture toughness is also calculated on the basis of the fractal dimension and the calculated result is 454.6 kJ/m², which is consistent well with the experimental result. This method could be used to estimate the fracture toughness of materials by analyzing of the fracture surface.     

Small punch testing for assessing the fracture properties of the reactor vessel steel with different thicknesses

Small punch (SP) tests have been performed at room temperature on round specimens with six kinds of thicknesses. Experimental results show that the SP energy, the fracture strain and the fracture toughness increase with the thickness of the SP samples. Fracture surface displays typical ductile fracture, and the outer surface of the hemispherical bulk part punched off is full of little bowings around which there are many microcracks caused by the stretch stress under biaxial strain/stress state. From the view point of the energy dissipation, the fundamental theoretical model of fracture toughness is proposed, according to which the ductile fracture toughness is obtained from the SP energy, the plastic deformation and the experimental fractography. The fracture strain and the fracture energy density criteria are introduced into the local failure model. With the continuum damage model, the FEA simulations provide the results of the crack propagation process which agree with the experimental results and can verify the fracture model.     

用示踪砂192Ir定量评价水力压裂裂缝宽度

针对目前油田水力压裂产生人工裂缝的重要参数缝宽，利用示踪砂¹⁹²Ir对压裂裂缝宽度进行定量化实验研究。首先建立模拟裂缝模型进行理论推导与计算，得到裂缝宽度与¹⁹²Ir射线强度的线性关系。在此基础上，制备用于示踪实验的示踪砂¹⁹²Ir，并将示踪砂混入填满支撑砂的模拟裂缝中。在裂缝宽度实验装置中，使用测井仪进行检测，得到裂缝宽度与¹⁹²Ir射线强度的实验关系曲线；最后通过现场实验验证了使用示踪砂评价水力压裂裂缝宽度结果的准确性。     

Numerical prediction of the fracture of a thick pressurized shell subjected to a liquid nitrogen shock

The probabilistic elastoplastic stress criterion for cleavage fracture is used in the frame of the local approach to fracture to analyse a fracture experiment in which a one meter long cylinder, with a longitudinal straight crack, was submitted to a thermal shock by liquid nitrogen. The computation, which gives the variation of the probability of fracture with time during the cooling transient, leads to predict a value for the most probable fracture time which is very close to the experimental one. The LEFM approach, which would predict a later initiation time can be improved by incorporating the probabilistic criterion in the frame of the small scale yielding analysis.