真空扩散连接CLAM钢接头的微观组织与性能

将CLAM钢采用真空扩散连接工艺进行连接后,观察分析采用不同连接温度和保温时间连接的接头微观组织,通过拉剪试验对接头的剪切强度进行评测.结果表明:在合适的连接温度和保温时间下用真空扩散连接的方法可以实现CLAM钢的可靠连接(结合率大于90%),接头剪切强度可达648 MPa.     

Be/中间层/HR-1不锈钢热静压连接界面特性

采用热静压方法进行Be/HR-I不锈钢的扩散连接,利用光学金相、扫描电镜(SEM)、俄歇电子能谱(AES)和X射线衍射仪(XRD)及材料试验机分析了接头扩散区的显微组织、元素和物相分布以及力学性能,讨论了Cu、Al和Ag-Cu合金作为中间层材料的作用.研究表明:Al作为中间层材料,不易实现Be/HR-I不锈钢的扩散连接;Cu和Ag-Cu合金作为中间层材料,能够实现Be/HR-I不锈钢的扩散连接,且Ag-Cu合金作为中间层扩散连接效果更好,更能有效地减少铍和不锈钢间的元素互扩散;Be与Fe和不锈钢中其他合金元素的脆性金属间化合物的大量生成,使接头质量较好.     

U-Mo合金与Al扩散反应特征研究

采用扩散偶方法研究了U-Mo合金与Al扩散反应特征.扩散偶以热压方式实现持续贴合.实验在真空热压炉中完成,热压温度550-570℃,时间5～21 h.结果表明:U-Mo/Al扩散层界面形貌和成分与扩散层厚度有关;在扩散层界面处U、Mo和Al的含量突变;U-Mo侧扩散层产物主要为(U,Mo)Al3,Al侧产物为(U,Mo)Al4和UMo2Al20.U-Mo/Al扩散反应是Al越过U-Mo/Al原始界面向U-Mo侧扩散并发生固体反应和扩散层向Al层生长的过程.     

微米厚Al-Al薄膜的超声摩擦焊接技术

传统的摩擦焊接以块材为研究对象，本实验利用改进的超声摩擦焊接(UFW)技术对20～25μm厚的Al-Al薄膜进行连接。采用白光干涉仪、光学显微镜及扫描电镜对单体Al薄膜和连接成型组件中的Al薄膜进行了表面粗糙度、厚度一致性和界面分析。结果表明，利用UFW可实现微米量级Al薄膜间的精密连接。同时，利用改进的UFW一次成型获得了一种高质量的双台阶Al-Al薄膜器件。     

Be与CuCrZr中温热等静压扩散连接研究

本文采用扫描电子显微镜(SEM)、能谱仪(EDS)以及X射线衍射仪(XRD)等方法研究了Ti/Cu作为过渡层在580℃、140MPa时不同时间下热等静压扩散连接的Be/CuCrZr合金接头的界面特征.结果表明:Ti较好地阻挡了Be、Cu之间的互扩散,其向Cu中的扩散比向Be中扩散快,发生了不对称扩散;两个样品在靠近Cu端的扩散区内发生准解理断裂;Be侧断口α-Be为主要相,存在一定量的BeO和Ti,Cu合金端断口以Cu为主要相,时间长的样品断口含有一定量的Ti、Cu化合物和少量的Ti,时间短的样品金属间化合物生成很少,且其Cu镀层存在织构,具有各向异性,严重影响接头的结合强度.     

用AES研究铝薄膜与基体金属铀之间的界面反应

在俄歇电子能谱(AES)仪超高真空分析室中利用氩离子溅射沉积方法将Al沉积在U基体上.对不同Al沉积量的铀表面实时采集AES和低能电子损失谱(EELS),以研究沉积Al原子与U表面原子间的相互作用以及Al膜的生长过程.将实验样品进行退火处理后进行深度剖析.研究结果表明Al沉积在U基体上是以岛状方式生长的;室温下,沉积Al原子与U表面原子间存在界面作用,两者在界面处相互扩散形成了合金相.退火促使界面扩散速率增大,界面结合力增强,并有可能形成化合物UAlx.     

射流圆孔靶的制备和靶参数测量

介绍了X射线激光射流实验中Al和CH两种射流圆孔靶的制备方法。分别采用精密机械和皮秒激光加工工艺在Al和CH薄膜上制备精密、微小的圆孔,再通过精密装配的方法获得射流圆孔靶。使用白光干涉仪和小型量测仪对射流圆孔靶进行靶参数测量,测量图像和数据表明,Al和CH薄膜圆孔的孔径较圆且两面大小一致性较好,靶的两层薄膜分界面清晰且连接紧密。     

0Nb-lZr与304不锈钢电子束熔钎焊界面微观组织研究

利用光学显微镜、扫描电镜(SEM)和电子衍射能谱仪(EDS)分析了Nb-lZr合金与304不锈钢电子束熔钎焊接头的反应相种类和界面结构.研究结果表明,接头界面生成了ε-( Fe2Nb)和σ-(FeCr)两种反应相,形成了两个反应层.反应层Ⅰ是Fez Nb的疏松组织,反应层Ⅱ是Fe2 Nb与FeCr的双相片层柱状晶组织.反应层Ⅰ是接头脆化、产生裂纹的主要原因.接头的强度与扩散层厚度有关,当扩散层厚度为22μm时,接头试样的强度达到355 MPa的最大值.     

金属铀表面铝薄膜生长行为的XPS研究

在室温、超高真空条件下,采用Ar离子溅射沉积的方法在清洁金属铀表面沉积铝薄膜,并利用X射线光电子能谱分析技术原位观察铝薄膜的生长行为.结果表明,在薄膜生长过程中,铀铝界面存在较明显的互扩散行为,同时发生一定程度的相互作用,生成金属间化合物UAlx,导致铀、铝XPS特征谱发生明显变化.铀铝间的互扩散导致U 4f谱在380.4、392.7和404.2 eV处出现新的能量损失峰;而铀铝金属间化合物的生成导致Al 2p XPS谱峰向低能端偏移0.2 eV.随沉积时间的增加,能量损失峰强度逐渐增强,Al 2p峰逐渐向金属Al特征峰位置偏移,说明随铝沉积量的增加,铀铝间的扩散行为增强,铀铝相互作用生成的金属间化合物组分并非单一.在沉积过程中,铝薄膜以岛状方式生长.     

金属铀与铝薄膜界面的俄歇电子能谱研究

以磁控溅射沉积方法 ,采用循环氩离子轰击镀和未循环轰击镀工艺在金属铀上制备了铝薄膜。俄歇电子能谱分析结果表明 :循环氩离子轰击镀获得的铝薄膜和铀基体的界面扩散比未循环轰击镀的显著增强 ,且界面发生化学反应 ,生成了UAl3和Al2 O3相。     

Sorption methods of separating barium and radium,aluminum and gallum,and zirconium and hafnium

Chromatographic methods of separating elements with very similar properties have now been developed. However, a number of these methods are difficult to use industrially as their throughput is low. The efficiency of chromatographic separation methods could be increased considerably by using appropriate complex formers, which decrease the effective concentration of the ions being separated, and,in the first approximation, this is equivalent to a decrease in the amount of elements being separated. The difference in the formation constants of the complex compounds increases the separation coefficient. By investigating chromatographic separation with the use of various complex formers, we found the optimal conditions for separating barium and radium, zirconium and hafnium, and aluminum and gallium. The throughput of these methods, with respect to the macroelement was 15–60 kg/hr per m² of column cross section.     

医源性电离辐射损伤及其生物医学防护

随着核与辐射技术在医学检查、诊断和治疗领域运用的增加,世界范围受照人群不断增多,医源性辐射已成为人类最主要的人工辐射来源之一。医疗机构和个人在选择利用放射手段获取诊断和治疗利益的同时,需要注意和防护伴随的辐射损伤效应。本文介绍了医源性辐射及其危害、机体组织的辐射损伤特性和类型、辐射生物效应分子及效应调节研究的进展,简要概述目前临床已经使用或最具应用潜力的辐射防护策略。     

Distribution and Fixation of Cesium and Strontium in Zeolite A and Chabazite

The selective removal and fixation of Cs and Sr have been studied in zeolite A and chabazite. Cesium ion was preferentially distributed into chabazite with a high distribution coefficient (K _Cs>10³ cm³·g^?1) in the presence of NaCl (10^?1 mol·dm^?3). The K _Sr values for zeolite A attained about 10³ cm³·g^?1 in the pH range of 8～10, and they gradually decreased with an decrease in pH.

The initial rate of Cs adsorption was fairly fast in chabazite, and the adsorption ratio reached almost 100% within a few hours. The adsorption ratio of Sr in binderless A zeolite reached almost 100% after 15 h. The adsorption of Cs and Sr on these zeolites was followed by Langmuir-type isotherm. Cesium forms of these zeolites recrystallized to pollucite (CsAlSi₂O₆) above 900°C for zeolite A and above 1,200°C for chabazite. As for Sr forms, these zeolites changed to SrAl₂Si₂O₆ above 900°C.

These recrystallized phases were suitable hosts for the immobilization of Cs and Sr in the nuclear waste solutions.     

清洁解控和退役若干动向与新发展

对国际辐射防护协会第 1 0届大会 ( IRPA-1 0 )涉及的清洁解控和退役问题作了论述 ,包括排除、豁免、清洁解控和废物最少化 ;退役工程技术的发展 ,包括去污技术、切割解体技术、探测技术 ;介绍了一个研究堆退役例子和加速器退役 ;最后 ,还论及了退役中受关注的一些问题 ,如 :石墨废物、混凝土废物、重水堆退役的氚防护、退役时间和退役废物量等。     

Plastic and dissipated work and stored energy

This paper depicts one theoretical and experimental method to take into account the energy phenomena, associated with the elasto—plastic deformation process, during the elaboration of behaviour laws. The energy balance definition is examined in order to relate the stored energy of cold work to the hardening state variables. Two experimental approaches are used to study the evolution of the energy balance. The first one uses microcalorimetric technique and the second infrared technique. Several industrial metallic materials are studied by both approaches. Energy data are used to control the validity domain of the classical behaviour laws and to elaborate new more appropriate ones. Therefore, the hardening parameters cannot be identified with the thermodynamical forces. The use of energy considerations allows the definition of new thermodynamical forces and state variables, in the case of isotropic or kinematical hardening.     

全国核与辐射安全监管信息系统的研究和建议

文章简要介绍了全国核与辐射安全监管信息系统的前期规划建设情况,包括基本建设内容、系统总体架构、以及工作中发现的影响和制约工作开展的主要问题,并提出了建议。     

Development and diversity and defense-in-depth application of ABWR feedwater pump and controller model

This work developed an advanced boiling water reactor (ABWR) feedwater pump and controller model, which was incorporated into Personal Computer Transient Analyzer (PCTran)-ABWR, a nuclear power plant simulation code. The feedwater pump model includes three turbine-driven feedwater pumps and one motor-driven feedwater pump. The feedwater controller includes a one-element/three-element water level controller and a specific feedwater speed controller for each feedwater pump. The performance tests, including step change of dome pressure, feedwater pumps transfer, inadvertent closure of all turbine control valves, and one feedwater pump trip at 100% power, demonstrate the feasibility of dynamic response of stand-alone model and incorporated model. Furthermore, a diversity and defense-in-depth analysis is performed to demonstrate the feasibility for motor-driven feedwater pump as an emergency core cooling system (ECCS) automatic diverse back-up. In Lungmen nuclear power plant (NPP), a diverse manual initiation means for the high pressure core flooder (HPCF) loop C is designed as the back-up of digitalized engineered safety features actuation system (ESFAS). If the motor-driven feedwater pump (MDFWP) can be an automatic digital diverse back-up for ESFAS, Lungmen NPP would be more robust to defend against software common-cause failure (CCF).     

Construction and operational experience with small and medium power reactors and expected improvements

Past experience with small and medium power reactors (SMPRs) in the areas of construction and operation is examined in this paper. Current development of SMPRs focuses on passive safety features; larger design and safety margins; reduction of construction periods through simplification, modularization and increased shop fabrication.