固态氚增殖包层中球床堆积性能研究

基于球床堆积实验和离散元数值模拟对包层中球床的堆积性能做了初步研究。圆柱形一元(单尺寸颗粒)球床的堆积性能的结果显示随着球床直径与颗粒直径比的增大,球床的平均堆积因子逐渐增高,实验与模拟结果一致;采用二元颗粒(双尺寸颗粒)、提高颗粒粒度比可以显著提高球床的堆积因子,二元球床的堆积因子随着大颗粒体积分数的增加先增加后减小,在大颗粒体积分数约为60%~80%时达到最大。优化了二元球床的填充工艺,最终二元球床的堆积因子基本达到0.8,但球床的均匀性欠佳。     

核电和物理学

20世纪三四十年代，原子物理学家们发现中子轰击铀原子核的裂变现象并首次实现可控裂变链式反应，把世界带进了原子能时代．半个世纪以来核电已达到全世界电力的16％．目前99％以上都是热中子反应堆核电站。在大规模发展核电的情况下，比如说百GWe,必须加快快中子增殖反应堆的发展和推广，方无核燃料匮乏之虞。     

Radiation effect of neutrons produced by D–D side reactions on a D–3He fusion reactor

One of the most important characteristics in D–³He fusion reactors is neutron production via D–D side reactions. The neutrons can activate structural material, degrading them and ultimately converting them into high-level radioactive waste, while it is really costly and difficult to remove them. The neutrons from a fusion reactor could also be used to make weapons-grade nuclear material, rendering such types of fusion reactors a serious proliferation hazard. A related problem is the presence of radioactive elements such as tritium in D–³He plasma, either as fuel for or as products of the nuclear reactions; substantial quantities of radioactive elements would not only pose a general health risk, but tritium in particular would also be another proliferation hazard. The problems of neutron radiation and radioactive element production are especially interconnected because both would result from the D–D side reaction. Therefore, the presentation approach for reducing neutrons via D–D nuclear side reactions in a D–³He fusion reactor is very important. For doing this research, energy losses and neutron power fraction in D–³He fusion reactors are investigated. Calculations show neutrons produced by the D–D nuclear side reaction could be reduced by changing to a more ³He-rich fuel mixture, but then the bremsstrahlung power loss fraction would increase in the D–³He fusion reactor.     

氚在锆合金包壳材料中的扩散行为模拟

基于氚扩散基本模型建立了氚扩散行为一维模拟程序,对模拟程序进行了典型实验验证,模拟结果与实验结果符合较好。分析了不同氚浓度、温度分布对锆合金包壳材料中氚的扩散行为的影响。分析结果表明：包壳-芯块间隙内氚浓度的升高会导致进出包壳的氚扩散通量提高,渗透通量增大;由于包壳氧化层相对较低的扩散系数,包壳氧化层的存在对氚渗透有较大的限制作用;温度对氚扩散速率的影响很显著,温度越高,扩散速度越快;锆合金外表面氧化层的相对低温限制了氚渗透出包壳管的速率,温度梯度导致的热致扩散有利于氚向包壳冷测扩散。     

CFETR水冷包层电磁结构耦合分析

利用软件Maxwell对中国聚变工程实验堆(CFETR)高场侧的水冷陶瓷增殖(WCCB)包层进行电磁分析,得到了包层在等离子体电流线性36ms衰减工况下产生的电磁载荷.采用载荷传递耦合法,结合软件ANSYS可得包层中产生的形变位移和等效应力.分析结果表明,WCCB包层中产生的最大等效应力符合设计要求,且形变位移均在许用...     

基于运行反馈的压水堆氚排放量研究北大核心CSCD

以压水堆核电厂中氚的产生机理和氚源项计算模型为基础,结合对国内外大量压水堆核电厂的氚排放运行数据的系统性分析,识别出冷却剂硼酸活化和次级中子源活化是压水堆氚排放量的主要来源,其中对中国广核集团运行机组,锑铍中子活化后的产氚量对氚年排放量的贡献可达到40%,而氚从完整的锆合金包壳的燃料棒中的释放是可以忽略不计的。由于优化次级中子源是降低压水堆氚排放量的唯一有效措施,通过分析建议压水堆核电厂采用双层不锈钢包壳的次级中子源或者取消次级中子源以降低压水堆氚排放。     

Recent Advances and Prospects in Design of Hydrogen Permeation Barrier Materials for Energy Applications—A Review

The hydrogen infrastructure involves hydrogen production, storage and delivery for utilization with clean energy applications. Hydrogen ingress into structural materials can be detrimental due to corrosion and embrittlement. To enable safe operation in applications that need protection from hydrogen isotopes, this review article summarizes most recent advances in materials design and performance characterization of barrier coatings to prevent hydrogen isotopes’ absorption ingress and permeation. Barriers are crucial to prevent hydride formation and unwanted hydrogen effects to increase safety, materials’ lifetime and reduce cost for applications within nuclear and renewable energy. The coating may be applied on a material that requires protection from hydrogen pick-up, transport and hydride formation in hydrogen storage containers, in pipelines, spent nuclear fuel storage or in nuclear reactors. While existing, commercial coatings that have been much in use may be satisfactory for various applications, it is desirable to evaluate whether alternative coating concepts can provide a greater resistance to hydrogen isotope permeation along with other improved properties, such as mechanical strength and thermal resistance. The information presented here is focusing on recent findings within the past 5–7 years of promising hydrogen barriers including oxides, nitrides, carbon, carbide, MAX-phases and metals and their mechanical strength, hydrogen pick-up, radiation resistance and coating manufacturing techniques. A brief introduction to hydrogen permeation is provided. Knowledge gaps were identified to provide guidance for material’s research prospects.     

Nachweis von Tritium in Eisenionen-haltigen wäßrigen Lösungen

Es wird über den Nachweis von Titrium in wäβrigen Borat- und Eisenionen-haltigen Lösungen durch Flūssigkeitsszintillationsmessung berichtet. Dabei wurde für verschiedene Dioxan-Szintillatorsystems die Zählerausbeute einer konstanten Menge HTO in Abhāngigkeit von der Zusammensetzung der Meβprobe ermittelt. Es konnte gezeigt werden, daβ mit Hilfe des Kanal-verhältnisverfahrens eine ausreichende Löschkorrektur erfolgen kann. Weiterhin wurde ein Szintillatorsystem so optimiert, daβ der Tritium-Nachweis in Lösungen mit einem Gehalt an Eisenionen unter 10^?7 Mol nicht beeinfluβt wird, wobei die Zāhlausbeute ūber 30% liegt. In wäβrigen Elektrolytlösungen, wie sie beispielsweise in der Korrosionsforschung bei der stufenweisen katodischen Reduktion HTO-haltiger Passivoxidschichten von Eisenoberflächen anfallen, ist somit die störfreie Registrierung des Tritiumgehaltes möglich.     

Tritiummessungen an Zuflüssen im Salzbergban

The use of data obtained from the analysis of tritium within the scope of the complex evaluation as to safety-in-mines of the hazards due to underground brine occurrences is based on a sure avoidance of the contamination of samples during the whole analysis. The article described a method on the recovery of uncontaminated sample water from the available, highly saline brine.     

Umweltisotope Zur Stüzung Eines Hydrogeologischen Konzepts im Mygdonias-Becken,Halbinsel Chalkidiki (Griechenland)

Abstract

Recharge areas in hard rocks of the margin of the Mygdonias-Basin (Greece) with the origin of thermal waters (max. 50°C) are assumed. Environmental isotopes, ³H, D, ¹⁸O. ¹³C, ³⁴S are supporting a concept of recharging normal temperated water along the northern margin of the basin, especially in the cross-area of tectonic faults.