采用高能重离子辐照研究铁素体/马氏体钢脆化效应

正铁素体/马氏体钢作为快堆组件的候选结构材料,辐照脆化是降低其堆内应用性能的关键问题,采用离子模拟辐照方法可大幅降低材料研究成本。对应于快堆服役环境的要求,采用高能重离子模拟辐照结合小冲杆测试技术对一种9Cr铁素体/马氏体钢的抗辐照性能进行了评价。     

快堆用HT-9研究进展

HT-9是含Cr量12%的铁素体/马氏体钢,是液态金属冷却快堆燃料包壳及外套管优异的候选材料。介绍了HT-9的研究进展,对HT-9在液态金属冷却快堆环境所需关键应用性能进行归纳和评述,对HT-9应用于铅冷快堆存在的主要问题进行了分析,给出了未来HT-9合金的主要发展趋势。     

中国实验快堆结构材料辐照装置设计

为在中国实验快堆(CEFR)上开展国产快堆包壳材料的辐照试验,进行了CEFR首个结构材料辐照装置的设计。材料辐照装置的创新设计基于CEFR的辐照条件和堆芯组件的基本结构,通过在辐照装置内部设置不同气隙尺寸的辐照罐,实现了在快堆不同功率稳态运行条件下(40%和100%额定功率)对材料样品不同辐照温度(450~600℃)的要求。辐照装置具有样品辐照温度与中子注量率的非在线监测功能,其结构具有通用性,能满足材料辐照标准试样最大装载的需要。通过对辐照装置进行热工分析和堆外的传热验证试验、流阻特性和结构稳定性验证试验,保证了辐照装置的设计能满足材料辐照任务的要求。     

先进反应堆用ODS F/M钢的强韧性匹配研究进展

氧化物弥散强化（ODS）铁素体/马氏体（F/M）钢具有极高的缺陷阱密度,加之体心立方结构基体,使其具有优异的抗辐照性能,被确定为包括聚变堆和第4代裂变堆在内的先进核能系统关键部件候选材料,成为核材料领域的研究热点。有利于ODS钢抗辐照性能的显微组织特点同时也赋予了ODS钢优异的室温和高温强度。但和其他高强度材料类似,ODS钢也存在强度高,而塑韧性不足的矛盾,不利于复杂部件的加工,因此,实现ODS F/M钢的高强高韧成为面向工程应用的ODS F/M钢研究的一大热点和难点。目前,针对ODS F/M钢强韧化的研究还较少,已有的相关研究也不够系统和深入,本文主要对抗辐照ODS F/M钢的显微组织结构要求及其强韧化研究现状进行总结和分析,为先进反应堆用抗辐照ODS F/M钢的强韧化设计提供思路和参考。     

先进反应堆用ODS F/M钢的强韧性匹配研究进展

氧化物弥散强化(ODS)铁素体/马氏体(F/M)钢具有极高的缺陷阱密度,加之体心立方结构基体,使其具有优异的抗辐照性能,被确定为包括聚变堆和第4代裂变堆在内的先进核能系统关键部件候选材料,成为核材料领域的研究热点。有利于ODS钢抗辐照性能的显微组织特点同时也赋予了ODS钢优异的室温和高温强度。但和其他高强度材料类似,ODS钢也存在强度高,而塑韧性不足的矛盾,不利于复杂部件的加工,因此,实现ODS F/M钢的高强高韧成为面向工程应用的ODS F/M钢研究的一大热点和难点。目前,针对ODS F/M钢强韧化的研究还较少,已有的相关研究也不够系统和深入,本文主要对抗辐照ODS F/M钢的显微组织结构要求及其强韧化研究现状进行总结和分析,为先进反应堆用抗辐照ODS F/M钢的强韧化设计提供思路和参考。     

用于制造KOHCSBTBM低活化铁素体／马氏体不锈钢的焊接技术的开发

韩国氦冷固体氚增殖堆试验包层模块的概念设计已经完成，还研究了试验包层模块概念的制造可行性。因此，很有必要研究开发其制造技术，如结构材料的连接技术，这是因为低活化铁素体／马氏体钢被公认为是韩国氦冷固体氚增殖堆试验包层模块的结构材料。几种类型的低活化铁索体／马氏体钢已得到推荐，但是它们的焊接性仍然在研究之中。本文详细地调查研究了低活化铁素体／马氏体钢的电子柬焊接技术，包括焊接样品在焊后热处理之前和焊后热处理之后的拉伸、硬度、冲击及微观结构等性能。结果显示焊接质量和本文应用的工艺是合理的。     

聚变堆低活化马氏体钢的发展

介绍了国际聚变堆低活化结构材料发展概况及趋势,以及国内发展自己特有的低活化马氏体钢的必要性。介绍了聚变堆结构材料——低活化铁素体/马氏体钢发展的必要性及迫切性,以及目前国际上包括欧洲、日本、美国等在此方面研究的进展概况及发展趋势,最后提出了国内发展自己特有的低活化马氏体钢——CLAM钢的必要性,并对目前的研究进展情况做了介绍。     

计入辐照效应的快堆燃料组件外套管截面变形有限元分析

快堆燃料组件外套管截面的辐照变形计算对快堆堆芯设计非常重要。本文研究考虑材料辐照蠕变和辐照肿胀效应,利用有限单元法计算外套管截面变形的方法。首先介绍了采用的辐照蠕变和辐照肿胀材料模型,其次给出了通过力学简化模型研究截面变形的理论方法,最后提出一种本构关系应力更新方案,通过将其编入ABAQUS子程序接口UMAT对外套管在压差作用下的截面变形进行了有限元分析计算,并比较讨论分析结果。结果表明有限元方法成功计算出了截面的变形,并在小变形时与理论解吻合较好。研究表明本文提出的本构关系应力更新方案是有效的;变形较大时理论解的偏差增大;内壁角点处应力水平最高,并伴随应力松弛效应。     

高燃耗下快堆燃料与包壳的化学相互作用模型建立及验证

快中子反应堆二氧化铀燃料元件在高燃耗、高中子注量率、高线功率和高温状况下运行,燃料与包壳材料会发生复杂的物理化学相互作用。燃料元件化学相互作用模型的建立对高燃耗快堆燃料元件的设计非常重要。针对快中子反应堆氧化物燃料元件与包壳材料发生的化学相互作用,采用动力学模型建立了二氧化铀与奥氏体不锈钢、铁素体-马氏体钢包壳材料的化学相互作用模型,并通过实验数据验证该模型。结果表明：建立的快堆二氧化铀燃料与奥氏体不锈钢的腐蚀模型可以成功预测最大燃耗10.8at%、辐照损伤87.5 dpa的包壳腐蚀;建立的快堆二氧化铀燃料与铁马钢的腐蚀模型可以成功预测最大燃耗9.3at%、辐照损伤76.6 dpa的包壳腐蚀。研究结果为高燃耗二氧化铀辐照元件及示范快堆燃料元件的设计和性能预测提供重要的参考价值。     

中国低活化马氏体钢CLAM研究进展

低活化铁素体/马氏体钢(RAFM钢)被普遍认为是未来聚变示范堆和聚变动力堆的首选结构材料。国际上给予了高度重视,许多国家都在研发其特有的RAFM钢。中科院等离子体物理研究所在与国内外多家单位的合作下发展了中国低活化马氏体钢———CLAM。本文总结了CLAM钢研制发展的主要进展,包括其成分优化设计、冶炼加工制备工艺、物理性能、机械性能、辐照性能及与液态LiPb的相容性等测试与研究以及各种焊接工艺研究等,并对今后的发展方向进行了展望。     

Sodium fast reactor evaluation: Core materials

In the framework of the Generation IV Sodium Fast Reactor (SFR) Program the Advanced Fuel Project has conducted an evaluation of the available fuel systems supporting future sodium cooled fast reactors. In this paper the status of available and developmental materials for SFR core cladding and duct applications is reviewed. To satisfy the Generation IV SFR fuel requirements, an advanced cladding needs to be developed. The candidate cladding materials are austenitic steels, ferritic/martensitic (F/M) steels, and oxide dispersion strengthened (ODS) steels. A large amount of irradiation testing is required, and the compatibility of cladding with TRU-loaded fuel at high temperatures and high burnup must be investigated. The more promising F/M steels (compared to HT9) might be able to meet the dose requirements of over 200 dpa for ducts in the GEN-IV SFR systems.     

Bootstrap calculation of ultimate strength temperature maxima for neutron irradiated ferritic/martensitic steels

The dependence of mechanical properties of ferritic/martensitic (F/M) steels on irradiation temperature is of interest because these steels are used as structural materials for fast, fusion reactors and accelerator driven systems. Experimental data demonstrating temperature peaks in physical and mechanical properties of neutron irradiated pure iron, nickel, vanadium, and austenitic stainless steels are available in the literature. A lack of such an information for F/M steels forces one to apply a computational mathematical-statistical modeling methods. The bootstrap procedure is one of such methods that allows us to obtain the necessary statistical characteristics using only a sample of limited size. In the present work this procedure is used for modeling the frequency distribution histograms of ultimate strength temperature peaks in pure iron and Russian F/M steels EP-450 and EP-823. Results of fitting the sums of Lorentz or Gauss functions to the calculated distributions are presented. It is concluded that there are two temperature (at 360 and 390 °C) peaks of the ultimate strength in EP-450 steel and single peak at 390 °C in EP-823.     

Corrosion-resistant coating technique for oxide-dispersion-strengthened ferritic/martensitic steel

Oxide-dispersion-strengthened (ODS) steels are attractive materials for application as fuel cladding in fast reactors and first-wall material of fusion blanket. Recent studies have focused more on high-chromium ferritic (12–18 wt% Cr) ODS steels with attractive corrosion resistance properties. However, they have poor material workability, require complicated heat treatments for recrystallization, and possess anisotropic microstructures and mechanical properties. On the other hand, low-chromium ferritic/martensitic (8–9 wt% Cr) ODS steels have no such limitations; nonetheless, they have poor corrosion resistance properties. In our work, we developed a corrosion-resistant coating technique for a low-chromium ferritic/martensitic ODS steel. The ODS steel was coated with the 304 or 430 stainless steel, which has better corrosion resistances than the low-chromium ferritic/martensitic ODS steels. The 304 or 430 stainless steel was coated by changing the canning material from mild steel to stainless steel in the conventional material processing procedure for ODS steels. Microstructural observations and micro-hardness tests proved that the stainless steels were successfully coated without causing a deterioration in the mechanical property of the low-chromium ferritic/martensitic ODS steel.     

Si含量对9%Cr铁素体马氏体钢微观结构和力学性能的影响

铁素体马氏体（F/M）钢是铅冷快堆堆芯的主要候选材料之一,提高Si含量可提高其抗腐蚀性能,但影响其微观结构和力学性能。为研发兼顾力学性能和抗腐蚀性能的高Si含量F/M钢,本文对Si含量（质量分数为034%、061%、080%、098%和120%）对9%Cr F/M钢微观结构和力学性能的影响进行了研究。结果显示,室温下通过正火（1 050 ℃,05 h,空冷）+回火（760 ℃,15 h,空冷）热处理制备的F/M钢均为全马氏体组织。钢的屈服强度和抗拉强度均随Si含量的增加而增加。Si含量对钢的组织及冲击性能的影响可分为两个阶段,当F/M钢中Si含量为034%~080%时,其组织、冲击性能变化很小;Si含量为098%~120%时,F/M钢中的第二相尺寸、数量增加,沿马氏体板条界面析出少量的Laves相,F/M钢的冲击韧性降低。本研究9%Cr F/M钢中Si元素的最优添加量应低于08%,使钢在保持较高强度的同时兼具良好的韧性。     

Response of nanoclusters in a 9Cr ODS steel to 1 dpa, 525 °C proton irradiation

Ferritic-martensitic (F/M) alloys are expected to play an important role as cladding or structural components in Generation IV and other advanced nuclear systems operating in the temperature range 350-700 °C and to doses up to 200 displacements per atom (dpa). Oxide dispersion strengthened (ODS) F/M steels have been developed to operate at higher temperatures than traditional F/M steels. These steels contain nanometer-sized Y-Ti-O nanoclusters for additional strengthening. A proton irradiation to 1 dpa at 525 °C has been performed on a 9Cr ODS steel to determine the nanocluster stability at low dose. The evolution of the nanocluster population and the composition at the nanocluster-matrix interface were studied using electron microscopy and atom probe tomography. The data from this study are contrasted to those from a previous study on heavy-ion irradiated 9Cr ODS steel.     

国产快堆材料与高温钠的相容性研究概况

概述了作为钠冷快堆结构材料和包壳材料的国产奥氏体不锈钢以及作为蒸汽发生器管材的铁素体低合金钢与高温钠相容性研究的主要结果和现状。     

Innovative materials for Gen IV systems and transmutation facilities: The cross-cutting research project GETMAT

Important Generation IV criteria for advanced fuel cycles are both improved efficiency and economical competitiveness. To reach these goals and keep high safety standards a key item is the availability of suitable structural materials. Ferritic/Martensitic (F/M) and Oxide-Dispersion-Strengthened (ODS) steels are indicated as the most promising candidates to withstand temperature, stress and irradiation fields expected in the core and primary system of most of the new generation reactors. In this context, the “Generation IV and Transmutation Materials” (GETMAT) project, sponsored by the EC, will contribute to the characterisation of ODS and F/M steels. The experimental and phenomenological aspects are complemented by the development of physical models aimed at describing and possibly predicting materials performance in operation.     

T91/15-15Ti异材焊接接头微观组织和力学性能研究

T91和15-15Ti是第4代核能钠冷快堆和铅铋快堆候选结构材料,国内外对铁素体/马氏体钢和奥氏体钢焊接性能、焊后热处理、焊接应力等进行了广泛的研究。本文对T91/15-15Ti试板焊态和热处理态焊接接头的焊缝、热影响区和母材微观组织和力学性能变化进行了研究,为T91和15-15Ti异材焊接参数选用和材料应用提供实验数据。     

超临界水冷堆燃料包壳管用低活性F/M钢的优化设计

应用热力学计算与实验验证,系统研究了Cr、W、C、Mn对高Cr低活性F/M（铁素体/马氏体）钢基体相及显微组织的影响规律,并在此基础上,对钢的组织和成分进行设计与优化,以适应超临界水系统对包壳材料的性能要求。研究表明：Cr是决定高Cr低活性实验钢中奥氏体Cr固溶量以及钢中是否出现铁素体的最重要影响因素;W和C对实验钢铁素体相的出现有显著影响,而Mn的影响相对较小;W对实验钢中Laves相出现的温度范围及数量具有显著影响,Laves相消失的临界温度随W量降低而降低;在不采用Co、Ni等奥氏体形成元素且不增加Mn量的情况下,通过调控W、C等含量,Cr含量≥11%的Cr-W-C-Mn系低活性F/M钢即可获得全马氏体组织。     

Nano-indentation measurement of oxide layers formed in LBE on F/M steels

Ferritic/martensitic (F/M) steels (T91, HT-9, EP 823) are candidate materials for future liquid lead or lead bismuth eutectic (LBE) cooled nuclear reactors. To understand the corrosion of these materials in LBE, samples of each material were exposed at 535 °C for 600 h and 200 h at an oxygen content of 10⁻⁶ wt%. After the corrosion tests, the samples were analyzed using SEM, WDX and nano-indentation in cross section. Multi-layered oxide scales were found on the sample surfaces. The compositions of these oxide layers are not entirely in agreement with the literature. The nano-indentation results showed that the E-modulus and hardness of the oxide layers are significantly lower than the values for dense bulk oxide materials. It is assumed that the low values stem from high porosity in the oxide layers. Comparison with in-air oxidized steels show that the E-modulus decreases with increasing oxide layer thickness.