聚变裂变混合堆的氚工艺和氚增值剂研究

本文简要介绍聚变堆氚工艺和氚增殖剂研究的现状和我所在混合堆氚增殖剂和氚工艺研究中取得的成果,并对这一领域的继续发展提出了一些建议． In this paper the recent status and unsolved problems on tritium technologyand tritium breeding material study for fusion-fission hybrid reactor (FFHR) are described.The achievements in the research area in our institute are briefly introduced.Some suggestions on further tritium research are given.     

FEB聚变实验增殖堆氚投料量及氚回收的研究

运用三维ＭｏｎｔｅＣａｒｌｏ程序ＭＯＲＳＥ＿ＣＧＴ，计算了变实验增堆ＦＥＢ满功率运行１０ｄ后外侧包层各区中的氚浓度、运行１天后的内侧包层各区中的氚浓度及运行１ＦＰＹ后Ｂｅ球中的氚投料量，设计了ＦＥＢ堆现场氚的分布流程图。采用组合于燃料净化系统和低温分馏法从等离子体排出气体中回收氚，讨论了从液态锂中回收氚的几种方案用于ＦＥＢ的可行性。     

LiAlO_2陶瓷小球的堆外放氚行为

将LiAlO2陶瓷小球置于裂变反应堆中辐照,采用热解吸技术研究该类产氚材料的堆外放氚特性,考察了升温速率、载气组分、催化活性元素和提氚温度对氚释放行为的影响;采用电子自旋磁共振(ESR)实验技术研究了辐照缺陷的顺磁特征。结果表明:LiAlO2中氚的扩散速度慢,热解吸活化能高,氚释放主要分布在750~1000K;表面氢同位素交换反应贡献大,释氚形态受载气条件的影响较大,当氦气中添加H2时,会增大HTO转化成HT的比例;中子辐照会在LiAlO2中诱生F+,O-和O2-等缺陷色心,其退火湮灭行为与氚释放过程存在一定关系。     

矩形管道载氚热磁流体输运特性的数值模拟研究

聚变堆液态金属包层矩形管道中的氚输运过程与磁流体动力学(MHD)流动传热过程耦合在一起,形成了复杂的载氚热磁流体输运特性。基于开发的MHD流动与传热数值模拟程序对矩形管道中液态金属MHD流动传热特性及其氚输运的影响进行了数值模拟。该程序首先求解了动量守恒方程,并与理论解进行了对比验证,然后与能量守恒方程耦合求解,得到了温度影响下矩形管道中的液态金属流场分布,在此基础上对强磁场高核热梯度影响下的氚浓度分布进行了数值模拟,得到了氚浓度在管道中的分布特性。结果显示,液态金属在矩形管道中的流动传热对氚输运过程产生了显著影响。     

LiAlO2陶瓷小球的堆外放氚行为

将LiAlO2陶瓷小球置于裂变反应堆中辐照,采用热解吸技术研究该类产氚材料的堆外放氚特性,考察了升温速率、载气组分、催化活性元素和提氚温度对氚释放行为的影响;采用电子自旋磁共振（ESR）实验技术研究了辐照缺陷的顺磁特征。结果表明:LiAlO2中氚的扩散速度慢,热解吸活化能高,氚释放主要分布在750~1000 K;表面氢同位素交换反应贡献大,释氚形态受载气条件的影响较大,当氦气中添加H2时,会增大HTO转化成HT的比例;中子辐照会在LiAlO2中诱生F+,O-和O2-等缺陷色心,其退火湮灭行为与氚释放过程存在一定关系。     

要认真探索异常核现象 含氘固体测氚实验的启示

 1989年3月Fleischmann和Pons报道了他们的“室温核聚变”实验以来已经快三年了.关心的人们都在探问:究竟现况如何?1991年12月6日Fleischmann主动到美国加州理工学院(C.I.T.)举行一场专题报告,接着又有人对当年C.I.T的Lewls等人所作的钯电极电解重水实验提出了新的解释.     

一般边界条件下球形压力容器钢壁中氚和氦-3的浓度变化规律研究

为了认识储氚高压容器壁材料的力学性能变化及其导致的容器承载能力变化, 必须研究储氚期间, 容器壁中氚和氦-3浓度的空间分布和随时间的变化. 针对容器外表面为一般传质边界条件和容器内部氚为范德瓦尔斯气体的情况, 同时考虑容器腔内和容器壁中氚的衰变和扩散, 建立求解储氚高压容器壁中氚和氦-3浓度的解析理论模型, 导出了氚和氦-3浓度的理论公式. 通过解析计算给出了器壁中氚和氦-3浓度随外表面传质系数的变化曲线和浓度的时空变化曲线, 提出了氦-3浓度的2β ₁ + β ₂ / 2倍定律, 即处于开放空间的储氚球形高压容器, 器壁中氦-3的浓度呈内高外低的分布, 时间越长, 浓度沿径向的梯度越大, 在时间足够长时, 各处浓度逼近时间无限长时的最终值, 也就是各处的最大值, 内表面处的最大值是该处氚初始时刻浓度的2β ₁ + β ₂ / 2倍, 这里β ₁ 和β ₂ 为与氚的范德瓦尔斯常数相关的参数. 研究结果为储氚高压容器的强度安全性评估提供了前提.     

聚变-裂变混合堆快裂变包层与抑制裂变包层的比较

以生产核燃料为主要目的的聚变-裂变混合堆包层,可采用两种不同的设计方案:快裂变包层和抑制裂变包层。它们各具有其长处和不足。本文以两个典型的包层结构为例,作了快裂变包层和抑制裂变包层的中子学计算和对比分析。其结果可作为包层选型设计及技术可行性、安全性、经济性分析的参考。     

基于点缺陷扩散理论与离散位错动力学耦合的位错攀移模型研究

位错的攀移运动对高温下晶体材料的塑性行为有重要影响,为了能够有效揭示攀移的物理本质及其对塑性行为的作用,本文基于点缺陷扩散理论,通过将体扩散和管扩散机理的共同作用与三维离散位错动力学耦合,建立了适用条件更广的位错攀移模型. 利用此模型我们模拟了单个及多个棱柱型位错环的收缩变形过程,发现影响位错攀移速率的决定因素不是传统理论认为的机械攀移力,而是位错周围(体扩散)及位错段上(管扩散)的空位浓度梯度. 该模型也能够完全重现棱柱型位错环群的粗化过程中不同位错环半径及晶体内平均空位浓度随时间变化的三个阶段. 关键词： 位错攀移 点缺陷扩散理论 位错动力学 棱柱位错环     

基于简单碰撞理论煤粉燃烧动力学模型的研究-PART Ⅲ:氧气可达比表面积

根据不同温度下氧分子平均自由程的大小,比较了小孔、中孔和大孔中三种扩散速率与煤焦表面燃烧速度的大小.研究表明2000 K以内,颗粒表面分子扩散速率比氧化反应速率大1个数量级以上,过度扩散速率不小于氧化速率.温度小于1200K时,燃烧速率比Knudsen扩散速率小1～5个数量级,扩散孔径小于15～28 nm,反应主要在内外表面进行;1200～1600K时,燃烧速率与Knudsen扩散速率相当,扩散临界孔径28～38 nm,反应在外表面及浅层内表面进行;温度1600K以上时,Knudsen扩散速率比燃烧速率小1个数量级,孔径38～50 nm以下内表面上碳的氧化速度受扩散控制.煤焦的氧化主要发生在Knudsen扩散临界孔径10～50 nm以上的氧气可达表面上.     

A simple polymer electrolyte membrane system for enrichment of low-level tritium (3H) in environmental water samples

Tritium (³H) is an essential tracer of the Earth's water cycle; yet widespread adoption of tritium in hydrologic studies remains a challenge because of analytical barriers to quantification and detection of ³H by electrolytic pre-concentration. Here, we propose a simple tritium electrolytic enrichment system based on the use of solid polymer electrolyte membranes (PEMs) that can be used to enrich ³H in 250–3000?mL environmental water samples to a 10-mL final volume. The IAEA PEM-³H system reported here can produce high enrichment factors (>70-fold) and, importantly, removes some of the deterrents to conventional ³H enrichments methods, including the use of toxic electrolysis and neutralization chemicals, spike standards, a complex electrolysis apparatus that requires extensive cooling and temperature controls, and improves precision by eliminating the need for tracking recovery gravimetrics. Preliminary results with varying operating conditions show ³H enrichments to 70-fold and higher are feasible, spanning a wide range of tritium activities from 5 to 150 TU with a precision of ～4.5?%. Further work is needed to quantify inter-sample memory and to establish lower ³H detection limits. The IAEA PEM-³H system is open source, with 3-D CAD and design files made freely available for adoption and improvement by others.     

Electrochemical conversion of carbon dioxide in a solid oxide electrolysis cell

Carbon dioxide is one of the greatest concerns worldwide, since it is not only a major greenhouse gas but also expected to be an important, sustainable resource for fuels and chemicals. The electrochemical conversion of carbon dioxide, based on solid electrolyte membrane reactors, has the promise to overcome the limitations of the conventional catalytic reactors such as the limited conversion and kinetics, relatively low selectivity and high energy consumption. In this review, electrocatalysts and solid oxide electrolytes, both proton and oxide ion conductors as core materials in an electrochemical ceramic membrane reactor have been reviewed and particular emphasis is placed on their application to synthesize carbon monoxide and hydrogen.     

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通过对聚变堆设计包层进行先后的一维、三维氚增殖比计算与分析,确定合适的模块材料、明确的模块划分以及相应的模块厚度,最终找到了合适的满足氚自持(TBR=1.3162)的熔盐设计包层.     

熔盐包层设计与氚增殖比的计算

通过对聚变堆设计包层进行先后的一维、三维氚增殖比计算与分析,确定合适的模块材料、明确的模块划分以及相应的模块厚度,最终找到了合适的满足氚自持(TBR=1.3162)的熔盐设计包层。     

中国聚变工程实验堆启动氚投料量与氚平衡分析

根据中国聚变工程实验堆(CFETR)堆芯设计参数及燃料系统流程模型,采用平均停留时间方法,建立燃料循环子系统的氚转移模型用来描述氚在各子系统之间的输运、滞留等过程。采用该模型,分析了不同聚变功率水平、运行因子以及燃烧率对中国聚变工程实验堆的氚平衡以及启动氚投料量的影响。     

The crystal change and "excess heat" produced by long time electrolysis of heavy water with titanium cathode

According to the theory given in the paper[1], the long time electrolysis experiment with titanium cathode in heavy water (D2O) were done for many times by using the open-loop multi-parameters electrolysis calorimetry system, which is established by us. The specialty is that the cathode is titanium rod and the anode is platinum wire. The early experiment result[3] is still repeated in our recent experiment. The obvious "excess heat" phenomenon can take place only when the electrolysis last more than ten days and amount of "excess heat" increased with the electrolysis time. The "excess heat" can also be obtained from the "boiling to dry" experiment. In the recent experiment, we obtain the results that the amount of "excess heat" is about 3.6 times the input energy, the "excess heat" power is 76.5 W, and the "excess heat" power density is 121.7 W/cm3. After the electrolysis, the crystal structure of the Ti cathode was measured with x-ray diffraction apparatus. We found that the crystal structure of Ti cathode was changed to face-centered cubic structure of TiD2 from its hexagonal structure. This result is in agreement with the Gou's theory mentioned in reference[1].     

Non-destructive assay and computational model for enrichment verification of UF6 cylinders

Verification of ²³⁵U enrichment in uranium hexafluoride (UF₆) cylinders is often achieved by destructive (DA) and non-destructive assay (NDA) techniques. These techniques are time consuming and need suitable and similar standard. This is in addition to the loss of nuclear material in the case of destructive analysis.This paper introduces an innovative approach for verifying of ²³⁵U enrichment in UF₆ cylinder. The approach is based on measuring dose rate (μSv/h) due to the emitted gamma rays of ²³⁵U at the surface of the cylinder and then calculating the activity of uranium and enrichment percentage inside the cylinder by a developed three dimensional model. Attenuation of the main ²³⁵U gamma transitions due to the cylinder wall (5B type of Ni alloy) was also calculated and corrected for. The method was applied on UF₆ cylinders enriched with 19.75% of ²³⁵U. The calculated enrichment was found to be 18% with 9% uncertainty. By the suggested method, the calculated total uranium activity inside one of the investigated UF₆ cylinder was found close to the target (certified) value (5.6 GBq) with 9% uncertainty. The method is currently developed by taking into consideration other parameters.     

光泵亚毫米波激光的理论模型及计算方法(Ⅱ)--多能级分子系统的激光增益系数

为了便于对光泵亚毫米波激光进行理论计算,从量子系统的密度矩阵方程出发,分别详细推导了三能级和四能级分子系统的激光增益系数表达方式以及多组独立三能级系统的增益迭加原理.     

A theoretical model describing the transfer characteristics of a membrane hydrophone and validation

This paper presents a theoretical model describing the transfer characteristics of a bilaminar polyvinylidene fluoride membrane hydrophone. The model applied uses a matrix formulation for one-dimensional propagation in multi-layered media. Arbitrary interconnections of piezoelectric layers are possible. The electrical transfer characteristics of the hydrophone leg and cable are modelled as transmission lines using a two-port network approach. The model is validated against measured open-circuit sensitivities for a 25 microm film thickness 0.5 mm active element diameter bilaminar hydrophone (50 microm total film thickness). Good agreement between theory and experiment is demonstrated. A 9 microm film thickness 0.5 mm active element diameter bilaminar hydrophone (18 microm total film thickness) together with amplifier is also modelled. The voltage at the output stage of the amplifier is measured and, by knowledge of the transfer characteristics of the complete system, the pressure waveform at the hydrophone position is estimated and compared with the acoustic pressure waveform derived using a laser interferometer. Good agreement is obtained.     

Interactions of lactoferricin B derivatives with model cell membrane studied by Raman spectroscopy

In this work, we employed Raman spectroscopy to study the effect of the antimicrobial peptide lactoferricin B (LfB) on model cell membranes. We used two derivatives of LfB (RRWQWRMKKLG and RRWQWR) with broad‐spectrum activity against gram‐positive and gram‐negative bacteria, fungus, viruses and tumors. Raman spectra of the peptides showed no conformational change in the temperature range 4–60 °C. The positions of the amide I and amide III bands suggest that in an aqueous solution these peptides preferentially adopt a random coil‐like conformation. We also investigated the effect the peptides had on the melting behavior of model cell membranes composed of zwitterionic lipid dipalmitoylglycero‐phosphocholine (DPPC) and anionic lipid dipalmitoylglycero‐phosphoglycerol (DPPG). Raman CH stretching bands were used to follow the melting of the lipid vesicles. We found that the melting of DPPC lipid vesicles is not affected by the presence of the peptides, while the presence of the peptides reduced cooperativity of the phase transition for anionic DPPG vesicle, suggesting that both peptides interact strongly and specifically with this model cell membrane composed of anionic lipid. Copyright © 2006 John Wiley & Sons, Ltd.