压水堆二回路工况下碱化剂对结构材料腐蚀的影响

利用长期浸泡的方法分析研究了压水堆二回路工况下A508Ⅲ和A106Gr.B低合金钢在乙醇胺(ETA)+二甲胺(DMA)、ETA、氨(NH_3·H_2O) 3种碱化剂中的均匀腐蚀行为,并利用扫描电镜、X射线光电子能谱和AES等技术分析了氧化膜的结构和组分。结果表明,在2 000 h试验后,A508Ⅲ试样在NH_3·H_2O中的腐蚀速率为0.15 mg/(dm~2·h),而在ETA+DMA条件下的腐蚀速率为0.087 mg/(dm~2·h),较在NH_3·H_2O中降低约42%。对于A106Gr.B材料,ETA+DMA环境的腐蚀速率相对于NH_3·H_2O环境下降约29.01%,说明复合碱化剂条件下,试样更耐蚀。氧化膜结构分析表明,氧化膜主要以Fe和O为主,ETA+DMA环境下的氧化膜厚度较薄,结构更加致密,氧化膜内含有N元素,说明胺分子参与了氧化膜的生成。复合碱化剂下材料耐蚀性提高的主要原因是由于复合碱化剂中的胺挥发性小于NH_3·H_2O,液相冷却剂pH值升高,减缓了Fe的氧化反应,另外胺分子易通过吸附作用吸附于氧化膜表面,降低了金属氧化反应的活化能,提高了材料的耐蚀性能。复合碱化剂与二回路设备材料具有较好的相容性,能有效降低设备材料的腐蚀速率,对于二回路水化学处理方法的改进有积极意义。     

压水堆二回路工况下碱化剂对结构材料腐蚀的影响

利用长期浸泡的方法分析研究了压水堆二回路工况下A508Ⅲ和A106Gr.B低合金钢在乙醇胺（ETA）+二甲胺（DMA）、ETA、氨（NH₃·H₂O） 3种碱化剂中的均匀腐蚀行为，并利用扫描电镜、X射线光电子能谱和AES等技术分析了氧化膜的结构和组分。结果表明，在2 000 h试验后，A508Ⅲ试样在NH₃·H₂O中的腐蚀速率为0.15 mg/(dm²·h)，而在ETA+DMA条件下的腐蚀速率为0.087 mg/(dm²·h)，较在NH₃·H₂O中降低约42%。对于A106Gr.B材料，ETA+DMA环境的腐蚀速率相对于NH₃·H₂O环境下降约29.01%，说明复合碱化剂条件下，试样更耐蚀。氧化膜结构分析表明，氧化膜主要以Fe和O为主，ETA+DMA环境下的氧化膜厚度较薄，结构更加致密，氧化膜内含有N元素，说明胺分子参与了氧化膜的生成。复合碱化剂下材料耐蚀性提高的主要原因是由于复合碱化剂中的胺挥发性小于NH₃·H₂O，液相冷却剂pH值升高，减缓了Fe的氧化反应，另外胺分子易通过吸附作用吸附于氧化膜表面，降低了金属氧化反应的活化能，提高了材料的耐蚀性能。复合碱化剂与二回路设备材料具有较好的相容性，能有效降低设备材料的腐蚀速率，对于二回路水化学处理方法的改进有积极意义。     

P11钢在湿蒸汽中流动加速腐蚀性能的模拟与实验研究

在核电厂中，二回路碳钢管道的流动加速腐蚀（FAC）对安全生产造成很大影响。根据工程经验和实验室数据，采用Cr含量超过0.1%的碳钢管道可大幅减轻或避免FAC。Cr含量大于1%的SA335-P11钢以其较好的性价比而多被推荐用于核电站蒸汽管道。为了确认P11钢表面氧化膜在高流速湿蒸汽作用下的稳定性，本文采用小型管状试样进行了FAC实验，得到了试样的减重规律和内表面的腐蚀形貌。实验结果表明，试样入口部分形成了明显的FAC形貌，表面氧化膜破坏严重，而在试样的中部，FAC不明显。CFD模拟结果表明，试样入口处局部流速较平均流速高约24%，表面剪切力大，与实验结果一致。     

奥氏体304NG不锈钢在550℃/25MPa超临界水中的腐蚀行为

研究了304NG不锈钢在550℃/25MPa超临界水中的腐蚀特性。采用扫描电镜、X射线能谱仪和X射线衍射分析了氧化膜的腐蚀形貌、组织结构和元素成分分布。实验结果表明，在550℃/25MPa的超临界水中腐蚀1000h后，304NG不锈钢显示出优越的耐腐蚀性能，其均匀腐蚀增重速率仅为0.01299mg•dm^-2•h^-1。304NG不锈钢在超临界水中形成均匀致密、但带有疖状腐蚀的双层氧化膜，厚度约为2.0μm，内层氧化膜致密而富Cr和Ni，外层氧化膜疏松而富Fe。     

候选材料在650 ℃超临界水中的腐蚀行为研究

研究了3种候选材料（347、HR3C和In-718）在650 ℃、25 MPa去离子水中的均匀腐蚀行为,使用场发射扫描电镜（FEG-SEM）和能谱（EDS）观察了不同腐蚀时间的表面氧化膜形貌与合金元素分布,使用掠入射X射线衍射（GIXRD）分析了氧化膜相结构。结果表明,3种材料腐蚀失重均符合抛物线规律,347的失重为HR3C和In 718的40倍以上;3种材料氧化膜均以Ni(Cr, Fe) ₂O₄为主,In-718点蚀严重,347氧化膜明显脱落,HR3C氧化膜较均匀致密;高温超临界水中,提高合金的Cr含量有助于增强均匀腐蚀性能,添加Nb有损合金的点蚀抗力。     

不锈钢及高温合金在拟临界区的腐蚀行为研究

研究3种高温合金和4种奥氏体不锈钢在380℃、25 MPa去离子水中的均匀腐蚀行为,使用场发射扫描电镜(FEG-SEM)和X射线能谱仪(EDS)分析不同腐蚀时间的表面氧化膜形貌与合金元素分布。结果表明,实验工况下合金腐蚀增重无明显规律,腐蚀失重均为对数规律;HR3C合金腐蚀失重最小,347合金最大,二者相差一个数量级。所有材料表面均能生成较为完整致密的双层氧化膜,外层相对贫Cr、Ni,缺Mo而富O。316Ti、718、825、800H、HR3C等多种合金出现点蚀,依照成分不同,点蚀区域呈现富Nb、Ti,贫Cr、Ni,缺Mn、Mo等现象。     

T91和316L钢在氧控铅铋中600小时后腐蚀产物分析

本文开展了铅铋反应堆典型候选结构材料T91和316L钢在温度480℃、氧质量分数10~(-6)%、流速0.3 m/s的铅铋合金环境中600 h的初步腐蚀实验研究。利用显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等微观测试手段,对材料的腐蚀界面形貌及产物进行了分析,初步结果显示:在实验条件下T91和316L钢基体均未发生铅铋渗透及溶解腐蚀现象,腐蚀类型均为氧化腐蚀。T91钢样品表面氧化层较厚(约11μm),且分为内外两层:外层结构疏松,主要成分为Fe_3O_4。内层结构致密,主要成分为(Fe,Cr)_3O_4;而316L钢表面单层氧化层较薄(约1μm),主要成分为(Fe,Cr)_3O_4。     

C-276合金在650℃/25MPa超临界水中的腐蚀行为

研究了HastelloyC-276（C-276）镍基合金在650℃/25MPa超临界水中的腐蚀特性。采用扫描电镜、X射线能谱仪、X射线衍射和X射线光电子能谱分析了氧化膜的腐蚀形貌、组织结构和合金元素分布。研究结果表明,C-276合金在650℃/25MPa的超临界水中的腐蚀过程主要是Ni的溶解,由于不能形成均匀、完整的氧化膜,合金在超临界水中并不具备优越的耐腐蚀性能,其双层结构的氧化膜富Cr而贫Ni、Mo,外层疏松的大颗粒（Ni(OH)₂和NiO）为金属溶解和氧化物沉淀形成,内层（Cr₂O₃）的生长则是水穿过氧化物微孔作用的结果。     

C-276镍基合金在600℃超临界水中的腐蚀产物及形成机理研究

使用x射线衍射、x射线光电子谱和扫描电子显微镜,研究了C-276镍基合金在600℃、25 MPa超临界水中的腐蚀产物.结果表明,合金在该环境下形成了比较均匀、完整的氧化膜,其组成主要是NiO、NiCr2O4、Cr2O3和M0O2;氧化膜为双层结构,整体贫Ni、Mo;内层相对富Cr,外层疏松,对合金缺乏保护性,内层致密,...     

奥氏体不锈钢在MIPR模拟溶液中的腐蚀行为研究

研究了304L和321不锈钢在80℃、MIPR模拟溶液中的均匀腐蚀、晶间腐蚀和应力腐蚀行为.实验结果表明304L和321不锈钢腐蚀1 500 h后的表面腐蚀轻微,具有良好的耐均匀腐蚀性能,且无晶间腐蚀和应力腐蚀趋势.这是因为两种奥氏体不锈钢腐蚀后表面均形成了以Cr2O3为主的致密氧化膜,阻止了腐蚀的进行,表面Cr(Ⅲ)形成的外膜和内膜的协同作用提高了膜的稳定性和耐蚀性.     

Study on fracture toughness evaluation method of SA738Gr.B steel heat affected zone in ductile-brittle transition region

The Master Curve (MC) method is widely used to evaluate the fracture toughness of ferritic steels for reactor pressure vessels in the ductile-brittle transition zone, but this method is only applicable to macroscopically uniform ferritic steels. Based on the measured fracture toughness data of China-produced SA738Gr.B steel Heat-Affected Zone (HAZ) in the as-welded and heat-treated state, the problems of the standard MC method for characterizing the fracture toughness of the HAZ are discussed. Then the Bi-modal master curve method (BMC), SINTAP method, and Single point estimation method (SPE) were used to characterize the fracture toughness of the HAZ of SA738Gr.B steel in the ductile-to-brittle transition zone. The comparative analysis found that the BMC method is better in terms of the accuracy of the estimation and the over-dispersion envelope was caused by the heterogeneity. The estimation results of the SINTAP and SPE models are conservative but can be used for the safety evaluation of the actual structure. The study provided technical support for SA738Gr.B steel to exempt post-weld heat treatment issue.     

HL-2A Tokamak Edge Modeling with B2

The outer divertor plasma of HL-2A and its associated scrape-off plasma have been simulated using a two-dimensional multi-species fluid code of Braams with a simplified neutral gas model. HL-2A has a double-null closed divertor in separate divertor chambers above and below the nearly circular plasma tours. The computed numerical grid is developed according to an ideal magnetic surface. The calculation is involved only with pure hydrogen plasma. The emphasis has been focused on parametric studies involving variation of the assumptions made for the core plasma. The peak temperatures and the heat flux near the target are of the principal concern。     

Creep in phosphorus alloyed copper during power-law breakdown

During the first phase of storage, creep will take place in the copper canisters in the KBS-3 package for nuclear waste. The temperatures are below 100 °C, and the creep is well inside the power-law breakdown regime. Creep models for this situation have been developed. The analysed material is pure copper with about 50 ppm phosphorus. Constitutive equations for creep and other plastic deformation have been set up based on a generalised Norton expression and Kocks-Mecking’s model for the back stress. A model for the minimum creep rate based on fundamental principles for climb and glide has been derived. This model gives the correct order of magnitude for the creep rate in the temperature range from 400 to 20 °C without the use of fitted parameters. The creep exponent varies from 5 to 105 in this interval. The constitutive equations have also been formulated for multiaxial stress states.     

The effect of phosphorus on creep in copper

Pure copper with an addition of about 50 ppm phosphorus is the planned material for the outer part of the waste package for spent nuclear fuel in Sweden. Phosphorus is added to improve the creep ductility but it also strongly increases the creep strength. In the present paper the influence of phosphorus on the strength properties of copper is analysed. Using the Labusch-Nabarro model it is demonstrated that 50 ppm has a negligible influence on the yield strength in accordance with observations. For slow moving dislocations, the interaction energy between the P-atoms and the dislocations gives rise to an agglomeration and a locking. The computed break away stresses are in agreement with the difference in creep stress of copper with and without P-additions.     

B4C/Na/S.S.三元体系化学相容性研究Ⅱ.相容时间及钠中氧含量的影响

将快堆控制棒模拟样品置于高温热对流钠回路中 ,于 550℃下进行B4 C/Na/S .S .三元体系化学相容性试验 ,研究相容时间及钠中氧含量对相互作用特性的影响。结果表明 :试验后的B4 C芯块完整 ,无掉角、龟裂或破碎 ;包壳管内表面渗B ,渗B量与相容时间的平方根成正比 ,渗B深度不随相容时间变化 ;包壳管内表面显微硬度明显升高 ,其升高幅度随相容时间增长略有增大 ,不同相容时间下的硬化层深度均约为 4 0 μm ;相容时间从 80d增加到 4 0 0d ,包壳管内表面相继出现反应产物Cr2 B ,Na4 B10 O17,B6Fe2 3,CrB和NiB ,NiB12 ;B向包壳管内表面的扩散与温度、相容时间及钠中氧含量有关 ,氧对B的扩散起促进作用。     

低能N~+诱变B.trispora(-)菌存活率-注量效应模型的构建

应用GCAS曲线方程对不同能量N+诱变B.trispora(-)菌存活率-注量效应关系进行了拟合,构建了存活率-注量效应模型。结果表明,三种能量的存活率-注量变化趋势均符合GCAS方程曲线,且拟合优度R2均在0.9834以上。利用存活率-注量效应模型对N+诱变B.trispora(-)菌的"马鞍型"存活率曲线进行合理的解释,对B.trispora(-)诱变选育工作具有指导意义,对其他霉菌的低能离子辐照诱变选育也具有一定的借鉴意义。     

法国—体化压水堆C.A.P述评

本文简要介绍法国一体化压水堆 C.A.P.的结构、非能动安注系统和主要特点。C.A.P.布置紧凑,自然循环能力强,固有安全性好,建造周期短,造价低,已成功地用于法国第二代攻击型核潜艇,适用于小型核动力,有重要参考价值.     

Heterogeneity of ion irradiation-induced hardening in A533B reactor pressure vessel model alloys

Reactor pressure vessels comprise bainitic steel structures, and are heterogeneous on the mesoscale. Nanoindentation techniques were used to evaluate the hardness of these structures on the micrometer scale, and to evaluate the heterogeneity in a specimen using the distribution of the hardness. Three A533B model alloys were irradiated by 2.8 MeV Fe²⁺ ions at 563 K, and the effects of ion fluence, ion flux, and chemical composition on the change in the hardness distribution were examined. Heterogeneity of the hardening is observed in high-copper specimens irradiated up to (2–10) × 10¹⁴ ions/cm², where the average hardness increases the most. In these specimens, the hardness distribution broadens, and demonstrates that the hardening in certain positions (possibly where the initial hardness is high) is greater than in other positions. Variation in initial chemical composition (especially copper and carbon) or sink strength may cause a difference in the curing behavior.     

Detrapping behavior of tritium trapped via hot atom chemical process in neutron-irradiated ternary lithium oxides

Tritium detrapping behavior in neutron-irradiated ternary lithium oxides was investigated by the comparison of the annihilation of irradiation defects with the tritium release. It was revealed that the annihilation of irradiation defects would consist of two processes; namely the fast and the slow ones. The slow annihilation process has correlation with the tritium release, indicating that E′-center or F⁺-center could act as tritium trapping site, and from its activation energy of each sample, the annihilation of E′-center and F⁺-center could be attributed to the recovery of oxygen via diffusion, triggering the tritium release. Meyer-Neldel plots of these results indicate that the slow annihilation process was governed by the formation entropy of a pair of vacancy and interstitial atom of oxygen. Therefore, the trapped tritium would be detrapped by oxygen recovery to E′-center or F⁺-center, and its kinetics would be determined by the population of oxygen vacancy under thermal equilibrium.     

Development of a coaxial tapered electromagnetic shock tube for beam-plasma non-linear interaction experiments

A coaxial electromagnetic shock tube was developed to produce a non-ideal plasma target with Γ ∼ 0.1 (Γ: Plasma coupling constant) for non-linear interaction experiments between ion beams and plasmas. To evaluate the shock velocity, we photographed the trajectory of the shock front along the tube by a streak camera. From these measurements, we found that the shock waves are strong enough to produce a non-ideal plasma in the tube. To reduce the plasma thickness for the stopping power measurements, the effective diameter of the tube was reduced by using a tapered section. The effects of the tapered section on the shock velocity and the shape of the shock front were examined. Using a 30 tapered section, the shock velocity was increased up to 54 km/s compared with 47 km/s for a straight tube.