软化热处理与预变形对CLAM钢塑性的影响分析

CLAM钢是中国ITER液态测试包层模块的首选结构材料,其塑性是影响测试包层冷却流道加工制造的关键因素之一。本文对CLAM钢进行退火软化热处理,测试其拉伸性能,并研究经过5%、10%和15%预变形,均分别在600℃、700℃和800℃回火30 min后,CLAM钢塑性的回复情况,以获得预变形量和回火工艺与CLAM钢塑性之间的关系,为制备包层模块及其冷却流道提供材料技术支持。研究表明:退火态CLAM钢塑性较正常热处理态CLAM钢有较大提高,在预变形和回火过程中,其塑性随预变形量的增大而下降,随回火温度的上升而提高。     

低活化马氏体钢的微观结构与力学性能

介绍了作为聚变反应堆候选结构材料的低活化马氏体钢的基本设计思路,初步确定了材料的化学成分和热处理工艺,研究了材料的冶金特性、微观组织和力学性能.同时,对比了添加少量钇和硅对材料性能的影响,发现添加硅可以提高材料强度,同时能保证材料具有足够的塑性和韧性;钇的添加对改善材料的塑性很有帮助,但是会使材料强度降低.     

提高1Cr14Co14Mo5不锈钢韧性的热处理工艺研究

针对因材料韧性不足导致的滚珠丝杠端头脆性断裂失效问题,开展马氏体沉淀硬化型不锈钢1Cr14Co14Mo5的改进研究。基于局部成分调整的1Cr14Co14Mo5不锈钢,将原有固溶+时效热处理工艺进行了调整,尝试利用循环相变热处理细化奥氏体晶粒的微观机制,获得细化的板条状马氏体组织,以提升材料的塑韧性。组织和性能结果显示,固溶温度由1000℃升高至1100℃可有效提高材料冲击韧性;3~4次的循环相变热处理能有效细化晶粒,晶粒平均尺寸小于10 μm,可使材料的冲击吸收能量（KU2）由20.2 J提高至60 J以上,同时断裂韧性值略有上升。      

De Beers公司的合成金刚石——硬质合金切削具和新的聚晶金刚石材料

De Beers公司生产的Syndrill金刚石——硬质合金切削具钻头,其生产率不仅超过锹形钻头,而且也超过牙轮钻头,能大幅度地降低钻探成本。新的切削具,在金刚石层与硬质含金支座的接合方法上,与第一种形式的金刚石——硬质合金切削具不同。SD-S,SD-M和SD-L切削具的硬质合金支座上没有烧结面。这有助于提高切削具抗冲击载荷和侵蚀能力,也能防止烧结时聚晶金刚石层因受热而遭到损坏。这次烧结时的温度比烧结钻头体内芯柱时的温度高得多。切削具没有烧结面简化了加工钻头时的二次烧结工艺。     

U3Si2-Al弥散型燃料板制备工艺对力学性能的影响

U2Si2-Al弥散型燃料板元件是一种新型低浓化的研究堆燃料，该元件制备工艺复杂，使用环境特殊，加工环节对弥散型燃料板力学性能影响较大，而弥散型燃料板的力学性能优劣是保证研究堆可靠使用的必要条件。本文针对现有的U2Si2-Al弥散型燃料板元件在不同热处理时的纵横力学性能进行了测试和分析研究。结果表明，弥散型复合燃料板芯体中的铀含量越高，燃料板的强度越低，现有退火工艺对燃料板的影响极大。由此，本文提出了改善燃料板力学性能参数的热处理方法的建议。     

管座的精密铸造工艺研究

叙述了燃料组件管座的精密铸造工艺特点。介绍了压型与芯盒设计、加工精度、快速取芯的型芯材料选择,腊模制造、浇冒系统的合理布置,防止冷隔、热裂采取的措施以及浇注试验和铸件检查结果。试验结果说明铸件的组织及精度满足设计要求。与焊接后精加工的工艺相比较,本精密铸造工艺流程简单、工艺成本低、铸件质量稳定,适合批量生产。     

大厚度不锈钢焊接质量控制

作者通过理论分析和实验研究,确定了大厚度不锈钢焊缝的最优合金系统(0Cr20Ni10)和最佳铁素体含量(3.5—6.5%),提出了低热输入快速埋弧自动焊方法(q≤1600J/mm,v≥34m/h)和焊缝结晶过程水喷淋冷却措施以及二级快速升温非敏化消除应力热处理制度。通过七个环节的质量控制,焊接质量极为优良。新的材料和工艺经产品焊接实践,证明其技术效果和经济效益是显著的。     

管座的精密铸造工艺研究

叙述了燃料组件管座的精密铸造工艺特点。介绍了压型与芯盒设计、加工精度、快速取芯的型芯材料选择,腊模制造、浇冒系统的合理布置,防止冷隔、热裂采取的措施以及浇注试验和铸件检查结果。试验结果说明铸件的组织及精度满足设计要求。与焊接后精加工的工艺相比较,本精密铸造工艺流程简单、工艺成本低、铸件质量稳定,适合批量生产。     

单点金刚石切削技术在EOS靶制备中的应用

针对激光状态方程(Equation of state,EOS)实验对靶的高精度、表面高质量、材料密度达到或接近理论密度的需求以及金刚石切削技术不改变原材料密度、加工精度高、粗糙度小的特点,阐述了单点金刚石切削技术(SPDT)在EOS靶制备中的应用情况,包括铝、铜等金属薄膜零件制备、多种结构整体式台阶靶制备、整体式楔形靶...     

辐照交联聚乙烯绝缘电力电缆的性能

研究了聚乙烯绝缘材料的辐射交联加工工艺。该材料可应用于电力电缆。它的各项性能均达到ＩＥＣ－５０２（１９８３）标准的要求。     

Laser welding and ablation cutting process for hydraulic connections by remote handling in the ITER diagnostic port plug

To assess hydraulic connections between subcomponents of the International Thermonuclear Experimental Reactor (ITER) diagnostic port plug, we investigated the laser welding and ablation cutting process, which can be applied to remote handling maintenance. In this study, laser ablation cutting, which vaporizes a small amount of solid material directly into gas by focusing a laser beam of high-density energy, is adopted in order to overcome the limitation of the normal laser cutting technology that the head should be placed as close to the work piece as possible to blow out melt metal at a distance. Complete cutting of a work piece is obtained by repetitive multi-passes of the laser beam. The welding and cutting process were tested on the sample work pieces and finally on a prototype of a hydraulic connection module for remote handling. The results showed that this process can be a promising candidate for hydraulic connections by remote handling. Furthermore the design of the hydraulic connection module has been updated to resolve some technical difficulties that were found during the test.     

旋压过程对马氏体时效钢组织性能的影响研究

某柔性连接件由马氏体时效钢管材经旋压、固溶、时效等工序加工而成。在其加工过程中存在材料易开裂、成品件材料延伸率低等问题。为解决上述问题,从各工序间的马氏体时效钢管坯上取样,通过金相分析、拉伸性能测试、硬度检测等表征,对旋压过程中组织和性能的变化规律进行分析。结果表明,成品件延伸率过低主要是由于旋压引起的形变强化造成的,多道次强力旋压会使马氏体时效钢晶粒破碎、位错密度和残余应力增加,导致成品延伸率仅为1%左右。通过优化工艺路线,可成功降低材料开裂率并将成品件延伸率提升至3%以上。     

某核电厂主蒸汽管道振动原因分析及解决方案探讨

某核电厂在升功率试验及满功率运行时,发现主控室的噪声超过了设计目标值。经过测量,认为主蒸汽管道振动并通过支撑和贯穿件传播到主控室是造成主控室噪声超标的主要原因之一。本文应用流体力学软件和声学分析软件,采用流声耦合分析的方法,对主蒸汽管道的流场和声场进行了分析。在主蒸汽安全阀支管处和主蒸汽隔离阀空腔中存在着声共振现象,是导致主蒸汽管道振动的主要原因。根据主蒸汽管道振动的原因,可以通过振动源头治理、传播路径治理等方法降低主控室噪声。      

自给能中子探测器关键材料及元件的研制进展

本文介绍了我国在运核电机组的基本状况以及国内核电自给能中子探测器的发展形势.详细分析了自给能中子探测器的结构特点、原理和应用,以及三代核电技术堆内核测系统的需求和使用寿命.阐述了自给能中子探测器用关键材料的国内外研制进展,重点分析了钒丝、铑丝和铠装信号电缆的制备工艺难点以及性能要求,阐明了钒丝、铑丝的高纯化与微量元素控...     

AP1000主泵下部C型密封环切割技术研究

三门核电厂采用美国三代核电技术AP1000，其1号、2号机组的大型屏蔽式主泵用于一回路冷却剂循环。在大修解体主泵时，需要开发专用切割方案与装置，以完成下部C型密封环切割。根据其主泵结构特点，确定切割方案的功能需求，并完成切割装置设计与开发；通过有限元分析，对装置的结构强度以及冷却效果进行验证与优化，保证切割精度以及使用寿命。所述切割方案与装置，适用于狭窄幽深空间，可实现定距切割，效率高、精度可靠、异物可控，且不产生空气辐射污染。该方案与装置可推广应用到同类型屏蔽式核电主泵检修工作中，并且具有一定的工业推广价值。      

UO2-不锈钢燃料棒的光纤激光切割研究

为验证光纤激光用于燃料组件解体和燃料棒切割的可行性,研究光纤激光用于热物性差别很大的UO2芯块 不锈钢包壳管复合结构的切割和铀芯块的切割质量,本文采用光纤激光切割UO2芯块 316Ti包壳管元件棒,并通过扫描电子显微镜、能谱和X射线衍射对UO2芯块的切断面进行微观表征分析,研究激光切割过程对铀芯块切断的表面微观形貌、元素组成及物相的影响。研究结果表明,光纤激光可用于切割UO2芯块 316Ti包壳管元件棒,激光切割过程虽会造成铀芯块切断面出现大量微孔和碎渣,但不会造成UO2的相变。以上结果表明,光纤激光可用于UO2芯块 316Ti包壳管元件棒的切割,通过后续对激光切割系统的抗辐射屏蔽防护,可应用于乏燃料组件解体和乏燃料棒切割。     

Fukushima Daiichi fuel debris retrieval: results of aerosol characterization during laser cutting of non-radioactive corium simulants

ABSTRACT

The production and dispersion of contaminated aerosols during the laser cutting of corium can potentially provide useful insights into the dispersion of contamination during the evacuation of damaged reactors during decommissioning. Quantitative assessments of contamination dispersion are fundamental to the development of a safety case for the decommissioning of the Fukushima Daiichi plant. This collaborative work between IRSN, ONET Technologies and CEA, managed by the Mitsubishi Research Institute on behalf of the Japanese Ministry of Economy, Trade and Industry, presents the characterization of aerosols generated during laser cutting of corium simulants both in air and under water.

The objective is to obtain quantitative data for risk assessment related to the contamination released and disseminated when implementing this technique, over the next few years, in the process of decommissioning the damaged reactors. This paper presents a part of the results stemming from this project, focused on the characterization of aerosols produced during laser cutting of two representative corium simulants in air and underwater conditions. The experimental configuration also enabled investigation of the production of other material residues such as particle dross and water purity on the particulate composition of the aerosols. Ultimately, the radioisotope concentration distribution in the aerosols are transposed to radioactivity in order to assess the risk to radiation workers during decommissioning.     

Cutting performances with new industrial continuous wave ND:YAG high power lasers: For dismantling of former nuclear workshops, the performances of recently introduced high power continuous wave ND:YAG lasers are assessed

Dismantling is a great challenge for nuclear companies which are facing with the cleaning of former nuclear sites. Among the available cutting processes is the multi-kilowatts laser whose power is transmitted through optical fibers. Unlike other cutting processes such as the plasma arc cutting process or the oxy-cutting process, the laser process can be easily implemented by robotic equipments. The mechanised robotic arm carries a laser cutting head to perform, with remote-controlled equipments, the cutting operation.The present study deals with the performances which can be reached with high power continuous wave ND:YAG lasers. The cutting tests were carried out up to 8 kW. The laser power was delivered through a specific power supply chain: a 0.4 mm fiber was transporting the power from the laser to a first interface (coupler) then a second 0.6 mm fiber was bringing the laser power to the cutting head. This solution allowed a power delivery chain whose length could be as high as 100 + 20/50 m. Another advantage of this kind of power supply is that the first fiber can be set in a non-contaminated environment whereas the second fiber lies in the contaminated area. The cutting head used for these tests was a specific tool developed for this laser dismantling work: it is a laser cutting head cooled by pressurized air. This tool was developed with the requirement to be able to sustain a laser power of 14 kW. The pressurized air used to cool the head is also used as cutting gas.The cutting capability was about 10 mm by kW. At the power of 8 kW, austenitic steel plates of thickness 100 mm were cut. These performances were reached with the cut started on the plate's edge. If the cut started in the middle of the plate, the cutting performances were not so high: 8 kW became the power to drill and to cut plates of thickness 40 mm.     

半导体硼柱形微靶电火花加工技术

在惯性约束聚变研究中,硼的柱形微靶可作为黑腔填充材料。本文通过电火花铣削加工技术,采用含碳较高的电介质,利用导电性能较好的钨钢作电极材料,实现了半导体硼柱形微靶加工。通过奥林巴斯测量显微镜对硼柱直径进行了测量,测量结果表明,硼柱的直径加工精度可控制在小于±10μm。采用扫描电镜对形貌进行了分析,结果表明,加工前后硼的表面形貌未改变。通过能谱分析了硼柱表面的导电层成分及通过X射线能谱(XPS)分析了碳元素价态,结果表明,电火花铣削加工过程中,由于电介质分解生成游离态的碳及电极材料熔融后沉积在硼表面,形成辅助导电层,通过对辅助导电层加工,产生的瞬时高温使硼熔融气化,从而实现对半导体硼的加工。     

Observation of the molten metal behaviors during the laser cutting of thick steel specimens using attenuated process images

Molten metal behaviors during the laser cutting of carbon steel and stainless steel specimens up to 300 mm in thickness were observed to dismantle large steel objects for the nuclear decommissioning, where attenuated process images from both steels were observed for detailed process analysis. Circular and rod-like molten metal structures were observed at the laser irradiated region depending on the assist gas flow conditions. Molten metal blow-off and flow processes were observed as cutting processes. The observations were explained by the aerodynamic interaction of the melted surface layer. The method is useful for the detailed observation of the molten metal behaviors, and the results are informative to understand and optimize the laser cutting process of very thick steel specimens.