The impact of the composition of structural steels on their corrosion stability in liquid Pb-Bi at 500 and 400 °C with different oxygen concentrations

In recent years, heavy liquid metals have found exercise as possible coolants and targets in the conversion of radioactive elements in accelerator driven systems (ADS). Liquid lead-bismuth eutectic alloy is one of candidates for this using tanks to its suitable nuclear and physical properties. Performed examination was aimed at research of compatibility choice materials for parts of ADS with liquid Pb-Bi eutectic alloy, influence of composition choice materials on their corrosion resistance, influence of temperature and oxygen content. We performed corrosion tests of 1000 h each on approximately 20 types of structural steels (austenitic, ferritic and martensitic) in convection loops with flowing Pb-Bi at 500 and 400 °C and using different oxygen concentrations. The impact of Fe, Cr, Ni, Mn, Si, Al and Mo content on the corrosion stability of these steels was measured without and after preliminary passivation through creating thin spinel or oxide layers on their surface.     

Oxygen measurements in stagnant lead-bismuth eutectic using electrochemical sensors

Sensors are the major part of an active oxygen control system (OCS) to be used in ADS reactors employing lead bismuth eutectic (LBE). We tested Pt/air and Bi/Bi₂O₃ probes based on yttria-stabilized zirconia (YSZ) solid electrolytes. The sensors were calibrated by evaluating the electromotive force (EMF) - temperature dependencies in oxygen un-/saturated stagnant LBE compared to the van’t-Hoff’s isotherm. Also, probe kinetics while changing the H₂/H₂O ratio was studied. Typical, reproducible curves are presented confirming attainment of oxygen equilibrium between the fluids. The sensor outputs are deterministic, predictable. Exceptional small drifts were due to interfacial kinetics, not to the sensors behavior. Simultaneous testing of several probes in one melt was performed. The sensors seemed to be qualified for large scale use.     

Preliminary results of post-irradiation examinations on LiSoR-2 test section

Liquid-solid reaction under irradiation (LiSoR) experiments are aimed at understanding the effects of liquid lead-bismuth eutectic (LBE) corrosion and embrittlement under irradiation on structural materials, which is one of the key items of the materials R&D for the future accelerator-driven system (ADS). The LiSoR setup is basically a LBE loop with a test section irradiated with 72 MeV protons. The second irradiation was conducted for about 34 h and terminated after a leakage of LBE was detected. Post-irradiation examinations (PIE) are being performed on both the tube and tensile specimen in the test section. Optical microscopy, scanning electron microscopy, transmission electron microscopy and microhardness tests have been completed. The results show that a crack formed in the irradiation zone of the tube. In the material in the irradiation zones of both the tube and the tensile specimen dislocation cell structure is well developed, which indicates heavy deformation due to thermal fatigue. The crack should start at the inner surface and propagate to the outer surface. The fracture surfaces of the crack are dominated by a brittle cleavage fracture mode. However, on the surfaces of the tensile specimen, no microcracks are observed.     

B51OL钢热物性参数的实验研究

为提高卷取温度的控制精度,同时为准确模拟B510L钢轧后冷却的温度场和分析工艺参数对品种钢组织性能的影响,采用激光脉冲法测得了B510L钢的热扩散率α;采用示差扫描量热计法测得了定压比热容Cp,最终求得了不同温度下的导热系数λ.实验结果表明:B510L钢的导热系数随温度的升高总体呈下降的趋势,但在相变区内有所波动.     

Overexpression of an F-box Protein Gene Reduces Abiotic Stress Tolerance and Promotes Root Growth in Rice

As one of the largest gene families, F-box domain proteins have important roles in regulating various developmental processes and stress responses. In this study, we have investigated a rice F-box domain gene, MAIF1. The MAIF1protein is mainly localized in the plasma membrane and nucleus. MAIF1 expression is induced rapidly and strongly by abscisic acid (ABA) and abiotic stresses. MAIM expression is also induced in root tips by sucrose, independent of its hydrolytic hexose products, glucose and fructose, and the plant hormones auxin and cytokinin. Overexpression of MAIF1 reduces rice ABA sensitivity and abiotic stress tolerance and promotes rice root growth. These results suggest that MAIF1 is involved in multiple signaling pathways in regulating root growth. Growth restraint in plants is an acclimatization strategy against abiotic stress. Our results also suggest that MAIF1 plays the negative role in response to abiotic stress possibly by regulating root growth.     

余热排出系统管道热疲劳分析模型及寿命预测

余热排出系统管道发现的热疲劳裂纹问题关系到压水堆的安全。本文基于开源有限元软件Code_Aster,采用Lagoda-Macha-Sakane模型预测了余热排出系统管道材料304L不锈钢的疲劳寿命,并根据预测结果提出了改进的Lagoda-Macha-Sakane模型。采用改进的Lagoda-Macha-Sakane模型对余热排出系统管道的热疲劳寿命进行了预测,结果表明预测热疲劳寿命与试验热疲劳寿命吻合。     

基于NRF24L01远程数据采集系统的设计

介绍基于89C51单片机和DHT22数字温湿度传感器利用nRF24L01无线射频芯片构成的无线温湿度采集系统。系统采用无线分布式结构,提高了节点的可移动性、节约系统实现成本,而且易于安装和维护;同时实现了对多个温湿度测量点的循环采集和显示,并利用串行通信将采集到的数据传送到上位机进行分析处理。经检验,系统具有良好的可靠性及较高的精度。     

硫铵装置中的加热器腐蚀原因

某装置中的316L不锈钢制加热器在运转不久即在管口局部区域发生严重腐蚀.经对加热器进行宏观检验和理化分析,认为该腐蚀是由于加热器在制造中引起了局部材料敏化而使耐蚀性能下降所致.提出了改进建议.     

304L不锈钢在Cl~-作用下腐蚀行为的研究

通过电化学噪声技术(EN)、动电位扫描法、噪声电阻(Rn)等方法研究了304L不锈钢在含Cl-溶液中的腐蚀行为过程,探讨了Cl-对304L不锈钢腐蚀行为的影响,以及腐蚀的形成、特征、机理。结果表明,由于有Cl-的存在,对不锈钢金属的钝化膜的破坏必然导致腐蚀过程中离子扩散速度的加快,因此,Cl-对304L不锈钢腐蚀行为有着明显的钝化作用。     

316L不锈钢波纹管膨胀节开裂原因分析与预防

某厂的316L不锈钢波纹管膨胀节在使用近3a(年)发生了穿透性开裂。采用化学成分分析、宏观及微观检验等方法对该波纹管膨胀节开裂的原因进行了分析。结果表明:氯化物应力腐蚀开裂是该波纹管开裂的主要原因,并提出了相应的预防措施。