重水质谱分析样品的制备

本文叙述了用同位素交换法制备重水质谱分析样品。此法制备的高浓重水样品被用于测定水中氘含量。制样的准确度估计为±0.01%。     

重水质谱分析

对高浓度重水进行了质谱分析,利用同位素交换平衡法制备了氘样品。根据实验工作的要求,部分地改进了МИ1301型质谱计。拟定了分析方法。对导致产生误差的各种因素进行了分析,引入了必要的校正值。给出高浓度(>99%)重水氘的百分浓度数据的准确度为±0.02%。     

中国先进研究堆氦气系统管道应力分析与评定

氦气系统主要功能：1）用氦气作载体将重水箱及重水贮存罐的内爆炸性气体带出，并将其合成重水回收；2）向重水箱和重水贮存罐提供氦气覆盖，以确保重水纯度；3）必要时可向系统补充氧气，以确保氘、氧的合成；4）必要时系统提供一定压力的氦气用于将重水收集罐的重水输送至重水贮存罐。模型示于图1。     

氢同位素的低温分离和重水的工业生产

自从1931年发现氢的重同位素——氘(又称重氢)以后,近三十年来,一些国家对氘以及氘和氧的化合物——重水的生产进行了研究。现时在可控制热核聚合方面的研究成果说明:在不久的将来,氘将成为热核反应堆的燃料;而重水是原子能反皮堆的减速剂和载热体。对于中等功率的原子能发电站,需要100—250吨重水,以重水反应堆为基础的动力工业,对重水的需要将是数千吨。随着原子能事止的发展,必须生产大量重水,以满足日益增长的需要。同位素分离方法包括:精馏,同位素交换,热扩散,质扩散以及其他分离方法(如电解、气体     

碳化硼中硼同位素丰度的质谱测量

通过直接测量碳化硼(B4C)粉末中硼同位素丰度组成,对固态涂样方式下硼热电离质谱测量方法进行研究。研究了涂样技术、升温程序、氧同位素影响扣除等问题。研究结果表明,直接针对固态B4C样品进行质谱测量,可简化样品化学前处理流程,缩短测量时间,减少实验人员所受剂量。     

质谱计系统误差的校正

用质谱计作同位素组成的绝对测定时,需要考虑仪器的系统误差。在质谱计中,测量的量是离子流的强度;由于质谱计存在质量甄别效应,因此离子流强度的比值并不完全等于试样中相应的同位素组分的比值。这就构成了仪器的系统误差,而且这个误差是质谱分析中主要的系统误差。为了校正这个系统误差,尼尔(Nier)最先使用了近于同位素纯的A~(36)与A~(40)人     

满江红鱼腥藻中氘的生物学同位素效应研究

用含重水０％、１０％、３０％、６０％、９０％的ＢＧ－１１培养基培养满江红鱼腥藻（Ａｎａｂａｅｎａａｚｏｌｌａｅ）并测定不同生长时间的光合活性、呼吸活性、固氮酶活性以及生长曲线，同时测定了室温吸收光谱及低温荧光光谱，用扫描电镜观察了细胞形态的变化。实验结果表明，重水使指数生长期后延，显著抑制光合活性、呼吸活性和固氮酶活性；随着重水含量的增加，藻胆素和类胡萝卜素的相对含量逐渐降低，光系统Ⅰ与光系统Ⅱ的相对荧光强度Ｆ＿（７３３）／Ｆ＿（６９５）变小，光合作用光能分配趋向于光系统Ⅱ。根据净光合最大值和固氮酶最大值讨论了氘的同位素效应。     

硼同位素丰度质谱测量方法的研究

通过检测天然硼同位素中的负离子BO2-,对天然硼同位素丰度比的质谱的测定方法进行了研究.对发射剂的选取、氧同位素贡献的扣除、质量歧视效应的修正等方面的研究表明,利用SrCl2作为发射剂,对硼同位素丰度进行质谱测量,可以简化样品前处理方法,减少样品进样量,降低分馏效应对测量的影响,提高数据的准确性和重现性,提高了热电离质谱测量微量硼同位素丰度比的不确定度水平.     

硼同位素热电离质谱测定中氰酸根干扰的消除方法

本发明涉及一种硼同位素热电离质谱测定中氰酸根干扰的消除方法，包括下述步骤：在利用热电离质谱测定涂样时将抑制剂与硼同位素样品按任意比例一起涂在样品带上进行硼同位素组成测定。本发明的方法主要是抑制CNO和Cs2CNO^＋离子合成，彻底消除CNO^-和Cs2CNO^＋离子对硼同位素组成测定的同质异位素的干扰。     

用GC-GCMS分析氢、氦同位素及氧、氮、一氧化碳的含量

本文叙述了用氖气作载气的毛细管热导池气相色谱(GC)与气相色谱-质谱(GCMS)并联的方法,同时准确地测定氢、氦同位素及氧、氮、一氧化碳的含量。样品量为10μl,测量精度为1.5-2.0％。用GCMS法测量了HD,HT和DT的原子离子与母体分子离子的比值,并发现同一母体离子的两种组成同位素的原子离子与分子离子的比值是不相等的,还观察到了CO对低温色谱柱分离性能的影响。     

高分辨氢同位素质谱仪的研制与应用

基于聚变核材料科研和生产、高温气冷堆产氚、氚放射性环境监测的需要设计了一套用于氢同位素分析的高分辨氢同位素质谱仪（HR-IRMS）,通过简单易操作的压强法配气系统,建立了氢氘氚配气装置。所研制的HR-IRMS仪器分辨率达2210,测量精密度达0.02%,相对原子质量范围为1~150。比对分析表明,其具有良好的运行稳定性和测定结果准确性,可实现氢同位素直接分析。     

Stable isotopes applied as water tracers for infiltration experiment

The δD and δ18O vertical profiles of soil water were measured prior to and after a rainfall event.Mechanisms of soil water movement were deciphered by comparing the soil water isotope profiles with the isotopic composition of precipitation.The results show that evaporation at the upper depth led to enrichment of the heavy isotopes.Compared to the loess profile,the shallow soil water of sand profile is relatively enriched in D and 18O due to macro-pore and low water-holding capacity.The precipitation is infiltrated into soil in piston mode,accompanied with significant mixing of older soil water.The preferential fluid flow in loess was observed at depths of 0-20 cm,caused by cracks in the depths.The hydrogen and oxygen isotopic compositions in outflow are close to the precipitation,which shows a mixing of the precipitation and old soil water,and indicates that the isotopic composition of outflow water is mainly controlled by that of the precipitation.The δD and δ18O in outflow decreased with time until stable δ values of outflow are close to those of the precipitation.     

热电离质谱直接测定铀氧化物中氧同位素

本文研究了热电离质谱（TIMS)直接测量粉末状铀氧化物中氧同位素的方法,涉及主要测量条件包括环境中氧、样品带材料、样品颗粒大小和测量方式等对测量结果的影响。对仪器的相关测量参数进行了优化,并建立了TIMS直接测量粉末状铀氧化物中¹⁸O、¹⁶O原子个数比的方法。对TIMS法与经典测量氧同位素的氧化法的测量结果进行了比较,两者的相对偏差为0.2%。TIMS法的¹⁸O、¹⁶O原子个数比测量精度优于0.28%。     

扫描电子显微镜结合热电离质谱测定单微粒中铀同位素比值

单微粒铀同位素分析是核保障环境监测技术的重要手段。作为现阶段应用最可靠且广泛的微粒分析技术之一,裂变径迹-热电离质谱(FT-TIMS)技术需依赖反应堆辐照,分析步骤繁琐,效率较低。扫描电子显微镜结合热电离质谱(SEM-TIMS)在保持原有TIMS的高测量精密度的同时,由扫描电子显微镜结合X射线能量色散谱仪(SEM-EDX)完成含铀微粒的寻找和鉴别,由微操作系统进行微粒转移,缩短了分析流程,提高了分析效率。本文应用建立的SEM-TIMS分析方法对已知同位素组成的单分散铀氧化物标准微粒进行了测量,测量结果与其标称值一致。     

氢-水同位素交换及其应用研究进展

简要介绍了氢气与水之间的氢同位素交换(氢—水同位素交换)的原理和相关理论研究,重点阐述了几种主要氢—水同位素交换工艺的研究和应用进展,并对氢—水同位素交换工艺在氢同位素分离中的应用前景进行了评述。     

Poisoning and saturation of St 737 getter alloy in the conversion of isotopic waters to isotopic hydrogen

The results of the studies performed to investigate the saturation capacity of St 737 getter alloy (Zr[V_0.5Fe_0.5]₂) in its application for conversion of water to hydrogen and the functional behaviour of the conversion reaction rate with large oxygen concentration in the alloy are reported. The experiment was performed with the getter alloy at a temperature of 400°C. The conversion process was monitored by two independent techniques — (i) by the hydrogen release, using a quadrupole mass spectrometer and (ii) by the quantity of water reduction in liquid phase. It was found that more than 100 mg of water was converted and 13 Pa m³ of hydrogen was released by a gram of alloy. A chemical analysis of the alloy performed after the experiment showed that the oxygen content in the alloy was about 7% by weight. The post-experiment diffraction analysis of the alloy showed that the crystalline structure of the alloy is almost completely destroyed and that the oxides formed are essentially amorphous. A brief discussion of the significance of the results for the application to tritiated water handling in future fusion reactions is also given.     

A 61 cm radius multi-detector mass spectrometer at the Australian National University

A 61 cm double-focussing magnetic mass spectrometer has been constructed incorporating three Faraday cups for simultaneous ion collection and a thermal ionization ion source. The operating characteristics of the mass spectrometer have been investigated using Mg beams. The isotopic composition of Mg in chemically purified samples as well as in individual single crystals has been measured. The present instrument has achieved a precision superior to conventional instruments, with significantly reduced analysis times.     

Resolution and calibration requirements for a time-of-flight mass spectrometer for analyzing gaseous fuel mixtures of a thermonuclear reactor

It is shown that to a large extent the isotopic and chemical analysis of gas mixtures can be performed using a time-of-flight mass spectrometer (mass reflectron), operating in a mode of synchronous detection to eliminate or substantially reduce the background current due to the beta decay of tritium nuclei. To this end, a mass reflectron with resolution ∼600 at 10% height of the peak near 3–4 amu has been developed and built and is now under investigation. Such resolution makes it possible to calibrate instruments by using special gas mixtures, study the relations of the atomic, molecular, associated, and trimer peaks of hydrogen isotopes under different conditions, and on this basis to develop a method for calculating the composition of real fuel mixtures from the experimental mass spectra. The apparatus also permits determining the composition of impurities over a wide range of their concentration in the entire mass range to a high degree of accuracy. __________ Translated from Atomnaya énergiya, Vol. 104, No. 4, pp. 233–237, April, 2008.     

Prospects for using chemical isotopic exchange for separation of hydrogen isotopes

The status of the production of heavy water in the world and Russia is analyzed. It is shown by comparing the main methods of producing heavy water that the most promising method for reprocessing untreated heavy-water wastes, including the removal of tritium from them, is isotopic exchange between water and hydrogen. The basic parameters of a pilot commercial setup, which makes it possible to obtain heavy water with a deuterium atomic fraction of 99.8%, are presented. The problem of removal of tritium from heavy-water wastes using the water-hydrogen system at the starting stage and hydrogen-palladium hydride at the final stage, is examined. The combination of methods developed makes it possible to produce a universal module for removing protium and tritium from heavy-water wastes. 1 figure, 2 tables, 20 references. D. I. Mendeleev Russian Chemical Engineering University. Translated from Atomnaya énergiya, Vol. 86, No. 3, pp. 198–203, March, 1999.     

氢-水同位素催化交换速率及过程模拟的研究进展

氢-水同位素催化交换在处理ITER聚变堆废水以及核裂变反应堆重水升级方面具有应用前景。该交换过程及核心设备催化交换塔的模型化研究,对工艺和工程优化设计具有十分重要的意义。本文重点介绍了氢-水同位素催化交换过程模拟的研究进展,讨论了同位素催化交换速率的计算方式以及吸收塔模型和滴流床模型在同位素催化交换过程模拟中的应用,探讨了氢-水同位素催化交换过程模拟今后的研究方向。通过各类模型的比较,滴流床模型被认为在催化交换过程模拟中有良好应用前景。氢-水同位素催化交换机理及速率计算方法和催化交换塔模型化等方面有待进一步研究。