In this paper, activated carbon was selected as the adsorption material to study the adsorption and desorption performance of krypton(Kr) and xenon(Xe) gases at various temperatures. A chromatographic quantitative loop tail gas collection column was prepared to achieve the capture of krypton and xenon in the tail gas of the chromatographic quantitative loop, by using activated carbon. The chromatographic quantitative ring tail gas collection column can operate at liquid nitrogen temperature and is used to capture the krypton and xenon gases in the tail gas of the chromatographic quantitative ring, and the lifespan of the gas collection column is no less than 500 injections. Two chromatographic quantitative loop tail gas emission modes, named venting mode and trapped mode were proposed. The emission mode that tail gas directly discharged into the atmosphere is called venting mode, and the emission mode that tail gas passed through the collection column and discharged into the atmosphere is called trapped mode. These two emission modes were selected to study the influence of the tail gas collection column on the performance of the gas chromatograph by comparing the gas flow rate, the retention time, half peak width, peak area response, and simulated samples measurement of noble gas components. There is no significant effect on the carrier gas flow rate under both modes. The absolute value of relative deviation of retention time in these two modes is no more than 0.3%, the absolute value of relative deviation of peak area response in these two modes is no more than 1.0%, and the relative standard deviation(sr) value of retention time and peak area response in these two modes is no more than 0.7%(n=7). Meanwhile, two types of standard curves of various noble gases in venting mode and trapped mode, two different emission modes are prepared, and all the linear correlation coefficients of standard curves of various noble gases are more than 0.999. Under the two tail gas emission modes, two types of standard curves in different emission modes were selected to measure three groups of identical samples. It shows that the absolute values of the measurement relative deviation of the same sample under the two tail gas emission modes are no more than 1.1%. The installation of the tail gas collection column has no significant impact on the quantitative analysis of the chromatograph. One set of standard curves of various noble gases can also be used under both tail gas emission modes, and there is no significant difference in the quantitative analysis results.

Radiation-resistant nanoporous adsorbent that can realize absolute CO2/Xe (Kr) separation without Xe and Kr loss is crucial, but yet to be achieved for accurate and reliable nuclear fuel burnup analysis. Herein, two hybrid ultramicroporous materials (NbOFFIVE-1-Ni and TIFSIX-3-Co) are presented for highly efficient CO2/Xe and CO2/Kr separation in the nuclear reprocessing off-gas. Nearly complete CO2/Xe (Kr) molecular sieving separations are achieved in NbOFFIVE-1-Ni with CO2/Xe and CO2/Kr selectivities both exceeding 11 000 before and after 50 kGy irradiation. Total photon cross sections of different elements, coordination number, and crystal orbital overlap population calculation that combines atoms, chemical bonds, and crystal structure are used to analyze the radiation stability of the hybrid ultramicroporous materials. Furthermore, the dynamic breakthrough and desorption measurement confirmed the ultra-low Xe (Kr) loss ratio (0.24% for Xe and 0.3% for Kr) of NbOFFIVE-1-Ni adsorbent under simulated reprocessing off-gas separation. This work not only provides a benchmark CO2/Xe (Kr) adsorbent for reliable nuclear fuel burnup analysis but also proposes a new perspective to understand the radiation stability of hybrid ultramicroporous materials.

Radioactive Xe isotopes are located at the heavy mass peaks of the fission mass distribution curves of 235U and 239Pu,with the characteristics of high fission yields and moderate half-life times,which have important application value in environmental radiation monitoring,international nuclear arms control and other nuclear event monitoring.The accuracy and reliability of nuclear data of radioactive Xe isotopes are valuable for its application,but there is often interference of radioactive Kr isotopes when measuring radioactive Xe isotopes.At present,cryogenic distillation is the main method for separating inert gas Xe and Kr in industry;however it is expensive and requires complex engineering control,which is not suitable for the preparation of nuclear data measuring gas sources.The adsorption separation method has been widely used in the separation and purification of various gas mixtures because of its maturity and low energy consumption.In order to prepare high activity Xe source for the measurement,the separation of low concentration Xe and Kr on CF-1450 activated carbon at room temperature and atmospheric pressure was studied.The pore structure characterized by N2 adsorption-desorption isotherm at-196 ℃ shows that the BET specific surface area of CF-1450 activated carbon is 1680 m2/g and the dominant pore size distribution is smaller than 2 nm.The capacity of CF-1450 activated carbon for separating Xe and Kr was evaluated by static adsorption and dynamic adsorption-desorption methods.The Xe and Kr henry coefficients of CF-1450 activated carbon at 25 ℃ are 0.21 mmol/(g·kPa)and 0.02 mmol/(g·kPa),respectively.The henry selectivity factor of Xe/Kr on CF-1450 activated carbon is 10.5,which is in agreement with the IAST selectivity(10.6,y(Xe)∶y(Kr)=50∶50)under the same conditions.The zero-point isosteric heats of Xe and Kr on CF-1450 activated carbon are 35.7 kJ/mol and 13.9 kJ/mol,respectively.Based on the dynamic separation capacity of low concentration Xe and Kr on CF-1450 activated carbon,an attractive procedure was proposed and showed good performance for preparing high activity Xe source.The recovery of Xe is 79％and the decontamination factor of Kr is 195.

Nuclear data, as the basis for the study of nuclear reaction and nuclear structure, are used to describe the properties of the nucleus and the reactions of the nucleus with other particles. The accuracy and reliability of nuclear data play important roles in nuclear fundamental research and nuclear technology application. The noble gas Xe can be used for neutron activation analysis of nuclear materials. However, it is necessary to separate radioactive Xe from Kr because of the interference of radioactive Kr isotopes when measuring radioactive Xe isotopes. Metal-organic framework (MOF) is a kind of porous crystalline material built with coordinate bonds between metal ions and organic ligands. The modular synthesis strategy of MOF makes them possessing adjustable pore size and adsorption performance, which provides the possibility for customized application. HKUST-1 and Co-MOF-74 are two representative MOFs that received extensive attention in the field of Xe/Kr separation due to the open metal sites in their pores. However, the stability of the two MOFs, especially in practical application environment close to radioactive Xe/Kr separation, still has not yet been studied. In this work, the HKUST-1 and Co-MOF-74 powders were shaped with polyvinyl alcohol as a binder, and the impact on the crystal structures of HKUST-1 and Co-MOF-74 in the shaping process was characterized by PXRD. The adsorption isotherms of N2, Xe and Kr on powder and pellets were tested by static adsorption method. The results show that the crystal structures of HKUST-1 powder and Co-MOF-74 powder are not obviously changed during the shaping process, and the BET surface areas of HKUST-1 pellets and Co-MOF-74 pellets decrease by 11% and 6% respectively. The capacity of Xe (Kr) at low pressure and 25 ℃ on HKUST-1 (Co-MOF-74) powder is almost the same as that of HKUST-1 (Co-MOF-74) pellets, and Xe/Kr Henry selectivity of HKUST-1 pellets and Co-MOF-74 pellets is 9.70 and 9.15 respectively. The stability of powder and pellets was studied by comparing the changes of specific surface area and infrared spectrum before and after the circumstance of 50% relative humidity, thermal cycling and γ ray radiation, according to the actual operating conditions of radioactive Xe/Kr separation. The stabilities of HKUST-1 pellets are better than those of Co-MOF-74 pellets in the circumstance of water and thermal cycling. HKUST-1 pellets and Co-MOF-74 pellets have good γ ray radiation resistance. A preliminary study on the separation of low concentration Xe and Kr using HKUST-1 pellets was carried out by adsorption-desorption experiment using fix-bed breakthrough column. Low concentration Xe and Kr can be efficiently separated by using HKUST-1 pellets as adsorbent in the fixbed breakthrough column using adsorption-desorption method, which provides a basis for establishing Xe/Kr separation procedure of MOFs required for the preparation of Xe source for nuclear data measurement.

提出了合金吸气剂除杂-气相色谱法测定混合气体中氪、氙含量的方法.样品通过减压进样装置进入气相色谱仪,选用管径为3.18 mm、长度为100 cm的不锈钢管为除杂柱,填装合金吸气剂,以消除氮气、氢气等杂质气体对氪、氙测定的干扰.结果显示:氪、氙的体积分数分别在4.55×10-4％～2.65×10-3％,5.60×10-5％～3.29×10-4％内与其对应的峰面积呈线性关系,检出限(3S/N)分别1.71×10-6％,1.65×10-6％;对混合标准气体重复测定6次,峰面积的相对标准偏差均不大于1.0％;按照试验方法与文献报道的气相色谱-质谱法对6个混合气体样品进行测定,相对偏差的绝对值均不大于1.0％.

Radioactive isotopes of xenon are produced in nuclear facilities,and must be trapped before released into the atmosphere.Study on the adsorption behavior of Xe isotopes in air or other gaseous medium is of great importance.For the perspective of engineering application,direct adsorption of multi-component gas at room temperature using activated carbon was studied.The comparison between multi-stage and single-stage carbon column adsorption was carried out, and the effects of condition parameters including carbon consumption were investigated.Experimental results show that single-stage carbon column is easier to be achieved in engineering application as compared with the way of multi-stage adsorbing column.For single-stage carbon column,the adsorbing efficiency of Xe reaches 90% with a gas flow velocity of 0.33 cm/s,and the resistance from the carbon bed is negli-gible in a certain flow velocity range (0.02-1.2 cm/s).

为满足大气放射性核素监测的需求,利用氙(Xe)与二氧化碳(CO2)、氡(Rn)等组分在活性炭吸附柱内脱附行为的差异,采用多级活性炭吸附柱吸附脱附的方法,对大气环境中的Xe(体积分数8.7×10 8)进行浓缩纯化,得到高浓度的Xe样品.研究了空气中的Xe、CO2及Rn等组分在多级活性炭吸附柱上的脱附曲线,选择Xe的脱附时段向下一级吸附柱转移吸附,对Xe进行逐级浓缩纯化.样品中Xe富集倍数可达105～106,Rn去污系数大于10 5,CO2体积分数低于4×10 5.此研究结果对于实现多组分混合气体中某一特定低含量组分的浓缩、纯化具有普遍指导意义.

在发生裂变反应的核设施中会产生放射性稀有气体氙(Xe)等.为保证反应堆的正常运行,须经过净化处理去除Xe等后才能排放,因此需滞留收集Xe等放射性气体.本文针对市售的5种多孔材料,包括颗粒状活性炭、分子筛和活性炭纤维3类,以材料的比表面积、孔容积为指标,结合Xe静态吸附容量,优选出性能较优的Xe吸附剂.研究了进气压力和吸附柱长径比对活性炭吸附Xe的影响,结果显示,活性炭吸附柱长径比为17∶1时,吸附性能最好.

Aerosol radionuclides （131I, 134Cs, 137Cs） and gaseous radioactive xenon （133Xe） were monitored at Xi’an, China following the accident at the Fukushima nuclear power plant in March 2011. The additional annual effective dose attributable to the Fukushima emissions was much lower than the public annual effective dose from natural radiation, according to Chinese national standards. The monitoring results were compared with data from other countries as well as with the radionuclide concentrations observed in Xi’an after the Chernobyl nuclear accident in 1986. Possible transport pathways of the released radionuclides from Fukushima to Xi’an were investigated. The occurrence of an anticyclone in the Pacific Ocean region and the extended period over which the radionuclides were released made the determination transport pathways complex, but divergence in the plume and easterly flow evidently brought the initial suite of radionuclides to Xi’an.

The absorption and separation method of Xe and Kr gas by active carbon was investigated.A standard mixture of Xe and Kr flowed through the active carbon column to be absorbed and enriched at low temperature(-78 ℃).The absorbed Xe and Kr were then deabsorbed from the carbon column separately.The analysis of the experimental data shows that the recoveries of Xe and Kr are greater than 90%.It can be concluded that the decontamination coefficient for Xe from Kr environment is above 104,while the decontamination coefficient for Kr from Xe is no less than 103.

An HPGe gamma-ray spectrometry system for radioxenon isotopes detection has been developed. The system was comprised of two low-energy planar HPGe detectors that were horizontally and oppositely placed, and a gas source cell made of carbon fiber in both sides was used. The spectra obtained simultaneously by the two HPGe detectors were analyzed by summing spectrum method. After the radioactive concentration of 133Xe was determined with three internal gas proportional counters, the efficiency of 81keV gamma-ray for 133Xe was calibrated to be 0.50 (1), and the Minimum Detectable Activity (MDA) for 133Xe detection was determined to be 10mBq during 1 day measurement time. Finally, the system was applied in atmospheric 133Xe monitoring at Xi'an of China after the Fukushima nuclear accident.

The retention time of Xe and Kr can be varied by changing the flow rate of carrier gas and temperature of the chromatography column packed with 5A molecular screen.It can be used for separating the noble gases.Test results show that an enhanced decontamination factor can be observed by extending the interval between retention times of Kr and Xe.Over 95% of the Kr and Xe can be absorbed by active carbon at –80oC.

In order to monitor radioactive krypton distribution in the environment,active charcoal is used to enrich krypton before the sample can be submitted to further laboratory analysis.The importance and method of krypton enrichment were presented.The absorption behavior of krypton by charcoal was analyzed.The experimental setup was designed to investigate effects of working temperature,linear velocities,partial-pressure of krypton on the enrichment of krypton by charcoal.The micro-structure parameters of the absorbing material to characterize its absorbing property was used,and the experimental data with theoretical analysis to conclude that for CF-1450 was fitted.The saturation absorption capacity at 191 K is 32.9 mL/g.

Oily wastewater from oil field by microwave induced and catalytic demulsification was studied in this paper. The advantages and prospects of the microwave technology was analyzed. Microwave treatment of oilfield wastewater has advantages such as equipment occupies a small space, easy to operate, portable, easy to transport, easy to installation and commissioning, short reaction time, high efficiency, discharge water which has good quality, temperature and other factors do not affect the treatment oilfield wastewater effect and so on. Microwave also has a bactericidal effect which was applicable to treat oilfield wastewater in both South and North of China. When the processing time is 2.5 min at temperature 57°C, microwave demulsification has the best effect. Based on the research of microwave demulsifucation mechanism, a conclusion is reached that microwave heating effect and microwave catalytic eddect play a leading role on the demulsification.

Radionuclide verification is one of four international monitoring systems that were stipulated by the comprehensive nuclear test ban treaty.The radioactive noble gas xenon is a gaseous fission product of nuclear fuels.The radionuclides of Xe are characteristic nuclides of nuclear explosion.A nuclear event that violates the treaty may be found by monitoring the variation of radioxenon(mainly ~(133)Xe~(m),~(133)Xe,~(135)Xe and ~(131)Xe~(m)) in global atmosphere through a global network of eighty stations of the international monitoring system(IMS).Therefore,it is necessary to research the sampling technology for xenon isotopes.The possibilities for sampling technology(including condensation and concentration of xenon isotopes) is explored from pre-separating and pre-condensing(microxenon) sample with FNQ-01 gas condenser experimental platform.The collecting efficiencies of microxenon influenced by the different condensing conditions were studied on this experimental platform.The best condensing conditions optimized with the orthogonal design method are showed respectively as follows: xenon concentration in sample 1.046×10~(-3),condensing temperature-198 ℃,gas flow rate 0.3 L/min,gas inlet pressure 55 kPa and evaporating temperature-50 ℃.The average collecting efficiency under these optimized conditions is 73%.Furthermore,the influences of different admitting methods to xenon collecting efficiency and condensation were discussed.

A simple PVT quantitative method of Kr in the high pure N2 was studied. Pressure, volume and temperature of the sample gas were measured by three individual methods to obtain the sum sample with food uncertainty. The ratio of Kr/N2 could be measured by GAM400 quadrupole mass spectrometer. So the quantity of Kr could be calculated with the two measured data above. This method can be suited for quantitative analysis of other simple composed noble gas sample with high pure carrying gas.

研究了在空气和含NO2气氛中不同温度下对GF/Cu皮芯复合导电纤维材料加速老化,力学性能、电学性能的影响,以及空气中高低温冲击导致其力学性能变化的规律.给出了导电纤维材料在不同环境中的氧化动力学曲线并分别计算了氧化激活能,推算出室温(25℃)条件下不同气氛中的储存氧化半衰期分别为:13.55年(空气气氛)、216.29天(氧化性气氛NO2:空气＝1:1)和374.75天(氧化性气氛NO2:空气＝1:2).

The static adsorption isotherms and adsorption rates of krypton and xenon at 201 K on viscose-based activated carbon fibres(VACF),pitch-based ACF(PACF),and granular activated carbon (GAC) are measured on a Micromeritics ASAP 2010M specific surface area and pore size distribution instrument by changing working gas of the instrument from N_2 to krypton or xenon. The results show that VACF has the same equilibrium adsorption capacity, but different adsorption rates for krypton and xenon.Because of the difference in their adsorption rates,sampling or concentration of krypton and xenon with VACF may lead to an alternation in their molar ratios.

通过正交设计优化了玻璃纤维化学镀镍的工艺条件,在此条件下研究了施镀时间与镀速之间的关系,同时对导电玻璃纤维的镀层成分进行了分析.研究表明,玻璃纤维化学镀镍后,大大提高了导电性能,可用于制备电磁屏敝材料.

通过正交实验优化了玻璃纤维化学镀铜的工艺条件,研究了提高镀液稳定的方法,同时对导电玻璃纤维的电阻率、镀层成分等参数进行了分析.研究表明,玻璃纤维化学镀铜后,可提高导电性能,并用作制备电磁屏蔽材料.