TRISO燃料颗粒三维多物理场耦合计算模型开发

三向同性燃料(TRISO)颗粒是高温气冷堆弥散型燃料和全陶瓷微密封(FCM)耐事故燃料芯块的裂变区。为研究TRISO燃料颗粒在辐照环境中的复杂行为,基于COMSOL有限元软件开发了TRISO燃料颗粒的三维多物理场耦合性能分析模型。通过采用随辐照条件变化的材料物性参数和行为模型,可模拟燃料颗粒在稳态运行和事故工况下复杂的堆内热-力学行为,以及CO气体产生和裂变气体释放、裂变产物扩散等重要物理过程,还可以计算燃料颗粒的失效概率。基于COMSOL开发三维分析模型的计算结果与美国BISON程序对TRISO燃料颗粒的计算结果相比同样符合较好,说明了所开发模型的合理性。     

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。     

气冷堆用棱柱型弥散微封装燃料性能分析及优化研究

棱柱型弥散微封装燃料是将三重各向同性包覆（TRISO）燃料颗粒弥散于金属或陶瓷基体形成的颗粒增强复合燃料,具有良好的结构稳定性、裂变产物包容能力和辐照稳定性,是高温气冷堆中较具发展前景的燃料形式之一。本文提出将TRISO燃料颗粒弥散于SiC基体的棱柱型弥散微封装燃料设计方案,并基于有限元分析软件COMSOL建立了该燃料元件三维热流固耦合分析模型,初步实现了该燃料元件性能分析和优化设计。结果表明,棱柱型弥散微封装燃料元件的温度最大值位于燃料元件外侧,应力峰值位于冷却剂通道壁面,边距比为0.76~0.84、孔距比为0.68~0.75时燃料元件热应力最小。本文建立的棱柱型弥散微封装燃料性能分析方法和研究结论,可为后续该型气冷堆燃料元件设计提供指导和参考。      

燃料棒辐照-热-力耦合行为的精细化数值模拟研究

在反应堆运行过程中燃料棒具有复杂的堆内行为,准确可靠的堆内燃料行为预测对于反应堆安全计算、燃料设计需求及燃料性能评估都是所必须的。本研究考虑了UO2芯块与锆合金包壳的相关热效应与辐照效应,并考虑间隙气体热传导、辐射换热、接触热传导的影响;分别编制用户自定义子程序,将燃料棒材料的辐照效应、热效应以及间隙换热等引入商用有限元分析软件ABAQUS,建立了燃料棒辐照-热-力耦合行为的精细化数值模拟方法。     

国外U3Si2与UMo燃料的发展现状

U3Si2-Al弥散型燃料是一种成功的低浓铀燃料,但在较高温度和较深燃耗运行时,其抗辐照性能急剧下降;UMo-Al弥散型燃料可能使任何高性能研究堆改用低浓铀,可是燃料相与铝基体的广泛反应引起严重的肿胀,期待含硅的铝基体能成功阻止这种反应的发生;单片型UMo合金燃料板具有较好的抗辐照性能,但制造方法尚不成熟。所有这些问题都亟待解决。本文首先简介了研究堆低浓铀燃料的发展简史,分析了U3Si2-Al弥散型燃料的成就与不足,讨论了UMo合金燃料所遇到的问题与需要解决的途径,提出了U3Si2-Al、UMo-Al弥散型燃料和单片型UMo合金燃料板的研究现状。     

俄罗斯研究堆高密度低富集度铀（LEU）燃料的研究现状

U—Mo燃料及其燃料元件和燃料组件（FA）的开发是俄罗斯RERTR规划的主要方向之一。该开发项目是基于现有的反应堆和新建先进反应堆的设计进行的,俄罗斯的很多组织参与了这项工作,如俄罗斯核燃料制备公司（TVEL）、动力工程研究和发展所（RDIPE）、核反应堆研究所（RIAR）、IRM和东北电网协调理事会（NPCC）。 开发中的U—Mo燃料包括弥散型燃料、单片式燃料以及管型和细棒型弥散燃料组件。第一阶段工作已顺利完成。该阶段包括管型和细棒状U．Mo弥散燃料的堆外、堆内和辐照后试验,试验是在近似于俄罗斯人设计的池型研究反应堆的运行参数条件下进行的。 俄罗斯和国外取得的成果证明可以进行下一阶段的研究工作,包括全尺寸IRT型细棒状和管型U·Mo弥散燃料组件的辐照,以及改善的U．Mo弥散燃料和微型单片燃料元件的辐照。本文对目前U—Mo燃料研究已取得的成果进行了全面的回顾。     

弥散板型燃料芯体强度的测试方法研究

铝基弥散型燃料元件具有许多优点,广泛应用在研究堆和材料试验堆中。七十年代末期,美国首先提出降低研究堆燃料中铀的丰度研究计划,在降低铀丰度(小于20％U~(235))的同时,需要提高芯体中燃料相的体积含量,这使弥散体的强度降低。因此,了解燃料相的含量对芯体强度的影响是很重要的。     

研究堆燃料的发展现状与前景

在过去33年中,国际降低研究和试验堆铀浓度计划已成功开发和应用了U₃Si₂-Al弥散型燃料。但由于U₃Si₂的抗辐照性能限制了它可能承受的运行温度与裂变密度,所以该燃料只适用于低功率密度的研究堆。U7Mo-Al弥散型燃料中的UMo颗粒与Al基体发生广泛的化学反应,将引起严重的肿胀与起泡问题。近年来,给U7Mo颗粒表面涂敷ZrN隔离层,获得防止反应的显著效果,使U7Mo-Al弥散型燃料有望应用于实践。U10Mo单片型燃料的芯体铀密度可达16g/cm³,辐照性能良好,但制造方法需进一步完善;应用中国核动力研究设计院改进的框架结构与轧制方法,能够控制UMo芯体与Al包壳具有相近的延伸率,从而可成功地轧制出合格的U10Mo合金单片型燃料板。     

改进弦长抽样方法开发及在弥散燃料蒙特卡罗模拟的应用

弥散型燃料广泛应用于高温气冷堆、事故容忍燃料、实验研究堆及核动力舰船等,是重要的燃料类型之一。弦长抽样(CLS)方法可简化弥散燃料几何建模,提高计算效率,然而传统CLS方法只能描述单种颗粒的填充,同时在高体积填充率时误差较大。针对CLS方法的两大问题,本文在自主化堆用蒙特卡罗程序RMC中开发了改进CLS方法,并应用于全陶瓷微胶囊封装燃料棒算例及含毒物颗粒的高温堆燃料球算例。计算结果表明,改进CLS方法可解决多种颗粒混合填充的问题,并且可保证体积填充率的准确性,为弥散燃料的临界及燃耗计算提供了高效、精确的方法。     

弥散型燃料裂变产物释放行为分析研究

为了获得弥散型燃料裂变产物向一回路冷却剂的释放特性,开展了弥散型燃料裂变产物释放行为研究,开发了适用于弥散型燃料的裂变产物源项计算程序,并对裂变产物源项进行了影响分析。结果表明:沾污铀和起泡破损后裂变产物的核素谱存在一定差异;裂变产物的释放与起泡当量直径的平方成正比;对于弥散型燃料而言,起泡破损中通过反冲释放的占比较低;相同破口条件下的弥散型和陶瓷型燃料中裂变产物的释放存在量级的差别。本文开发的程序能够用于分析弥散型燃料的裂变产物源项,为后续相关研究工程设计奠定基础。      

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.     

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).     

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。     

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.