放射性废离子交换树脂高温裂解处理技术研究

通过热重实验以及台架试验,进行了废阴/阳离子交换树脂的高温裂解处理技术研究。结果表明,通过电磁感应加热反应器中的金属球并辅助搅拌,可以实现树脂的高温裂解。相比于氮气和水蒸气,空气是更合适的反应气氛。在空气氛围下,当树脂处理量为1 kg/h时,设定空气流量2 m³/h,反应温度600 ℃～700 ℃,添加剂选择CuSO₄·5H₂O,阴/阳离子交换树脂经本裂解工艺处理,废物残留率分别为8%和12%左右,两种树脂最终的裂解残留率可以达到3%～5%左右,可以实现较为彻底的裂解反应。阴离子和阳离子交换树脂的裂解反应有明显的区别,其中阴离子交换树脂热敏性更高,裂解需要的温度和空气流量更低,但反应更剧烈,烟气量更大。     

放射性废离子交换树脂特种水泥固化体的微观结构分析

研究了特种水泥 (ASC)树脂固化体的微观结构。用压汞实验比较了ASC特种水泥的树脂固化体和普通硅酸盐水泥 (OPC)固化体多孔性能 ,通过电镜扫描 (SEM )观察比较了ASC和OPC的微观晶体结构。分析结果发现ASC水泥固化体具有较好的孔形结构 ,这是ASC固化体浸出率低的原因 ;ASC水泥固化体晶体呈针状结构 ,OPC水泥固化体晶体呈片状结构 ,针状结构的力学性能和结构强度要比OPC的片状结构好 ,该结构是ASC固化放射性废树脂包容量大、强度高的根本原因。     

放射性示踪技术研究金,铂在新型大孔树脂HHY—10A上的离子交换行为

应用１９５ｍＰｔ、１９９Ａｕ放射性示踪剂研究了金、铂在一种新研制的大孔强碱性阴离子交换树脂上的离子交换行为。系统研究了吸附和洗脱的条件，包括吸附介质的成分和酸度、洗脱剂以及吸附和洗脱流速的影响等。应用此法从标准参考物质ＤＺΣ－１、ＤＺΣ－２中分离和浓集出Ａｕ、Ｐｔ，用ＩＣＰ－ＭＳ测定，分析结果与推荐值符合良好。     

过氧化氢湿法氧化 IRN78阴离子交换树脂的初步研究

使用过氧化氢湿法氧化技术对核级IRN78阴离子交换树脂进行了氧化降解初步研究。 研究中用硫酸对阴离子交换树脂体系pH值进行了调节,比较了催化剂Fe²⁺、Cu²⁺、Fe²⁺/Cu²⁺混合催化剂对H₂O₂-阴离子交换树脂的催化效果。研究结果表明:使用混合催化剂Fe²⁺/Cu²⁺的摩尔数比为1∶2时湿法氧化IRN78阴离子交换树脂的催化效果优良,氧化降解率达到了99.7%,过氧化氢的利用率达到了 92.7%。实验结果表明过氧化氢湿法氧化技术对于 IRN78阴离子交换树脂有良好的氧化降解效果。     

Study on the leachable behavior of cation exchange resins

The amount of total organic carbon (TOC) leached from cation exchange resins (CERs) in condensate demineralizers are related to the quality of reactor water in nuclear power plants (NPPs). In the recent years, quality problems of CERs used by ChinShan and KuoSheng NPPs have been identified. Prior to use, TOC and sulfate concentrations must be reduced to meet the criteria; however, this involves an extended purification process and heavy use of water resources. Even in cases where resin can be used, the quality of the water in the reactor remains poor. This study, therefore, investigated the leachates of resins from these NPPs in order to establish a reference for the quality of deep bed CERs. Gel permeation chromatography and ion-pair chromatography were used to identify molecular peaks in the CER leachates in order to elucidate the molecular distributions. We also sought to determine TOC and sulfate concentrations of post-UV treatment using long-term soaking tests, in which the solutions used to soak resins were drained off for analysis on a daily basis. Hydrogen peroxide is employed to accelerate the aging process associated with decomposition in soaking tests to determine the stabilities of the resins.     

Low-energy ion scattering and sputtering at grazing ion bombardment of clean and oxygen covered Ag(1 1 0) surface

The ion scattering and sputtering processes at low energy grazing N⁺ and Ne⁺ ion bombardment of clean and oxygen covered Ag(1 1 0) surface have been investigated by computer simulation in the binary collision approximation.

The spatial, angular and energy distributions of scattered, sputtered particles and desorbed molecules of oxygen as well as their yields versus the angle of incidence have been calculated. In these distributions the some characteristic peaks were observed and analysed. It was found that an adsorption layer plays a role of the additional surface barrier, i.e. it reflects leaving target atoms back to crystal. The azimuth angular dependencies of Ag sputtering yield and non-dissociative O₂ desorption yield at grazing incidence have been calculated. It was shown that these dependencies correlate the crystal orientation.     

α能谱法测量尿中的~(241)Am

以241Am为指示剂,采用共沉淀的浓集方法浓集尿中的镅,经阴离子交换法分离纯化,然后电镀制源,用低本底α测量仪和α谱仪对尿中的241Am进行测量。在加入10-3Bq241Am指示剂的情况下,回收率可达到60%以上。结果表明,用这种方法可以对尿中10-3Bq的241Am进行定量分析,结果的不确定度小于40%。     

温度对液态金属离子源发射特性的影响

根据物体加热过程的温度滞后效应，测定了不同温度下的液态金属离子源的Ｉ－Ｖ特性曲线，起始电压与温度的关系，Ｉ－Ｖ曲线斜率与温度的关系曲线，并对所得实验结果进行了讨论。     

Resonant ion stimulated desorption of O from the TiO2(1 1 0) surface: Effects of oxygenation and ion bombardment

The O⁺ desorption from reduced, oxygenated, and ion-bombarded TiO₂(1 1 0) surfaces has been investigated during He⁺ irradiation. The O⁺ desorption is initiated by creation of an antibonding O 2s core hole state via quasi-resonant charge exchange with the He⁺ 1s state, followed by the intra-atomic Auger decay of the O 2s hole. Upon oxygenation of the reduced TiO₂(1 1 0) surface, the O⁺ yield increases by one order of magnitude. The O₂ molecule is dissociated at the vacancy site of bridging oxygen and the oxygen atoms either fill a vacancy site or chemisorb at a fivefold-coordinated Ti⁴⁺ site as an adatom. The latter is detected with much higher efficiency than the former. The O⁺ yield is increased during He⁺ bombardment of the reduced TiO₂(1 1 0) surface due to formation of lower coordinated oxygen atoms. The oxygen species thus formed by ion bombardment or oxygenation are unstable on the surface and tend to diffuse into bulk vacancy sites or higher coordination surface sites even at room temperature.     

离子注入对电器触头性能的影响

对两种电器触头注入1×10~(17)/cm~2的氮离子,然后做低压电器通断试验,测量了触头的重量损失、温升、接触电阻、触头材料转移等参数,发现离子注入方法处理对电器触头性能有不同程度的改善。     

Investigating the performance of a Rh metal catalyst in hydrogen–deuterium exchange reactions in methane for application in low-temperature membrane separators

The development of safe, efficient, and cost effective methods to recover waste components of deuterium–tritium (D–T) plasma reactors, including hydrogen and methane, has attracted much interest in the scientific community. Typically, membrane separators are used for this process, although several problems occur when performing separations at higher temperatures. The application of noble metal catalysts may improve the reaction dynamics and allow the separation process to occur at lower temperatures. In this paper, a series of noble metal catalysts were prepared by a traditional dipping method. Based on an analysis of catalytic performance, the Rh/Al₂O₃ catalyst was determined to be the most suitable for the exchange of hydrogen and deuterium in methane. The catalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and temperature programmed reduction analyses. The effects of the metal loading and experimental conditions were also investigated.     

中性粒子对强流脉冲离子二极管工作过程的影响

研究了强流脉冲离子二极管中阳极等离子体中的冷中性粒子与束离子的电荷交换条件以及电荷交换作用对空间电荷限制电流密度的影响，电荷交换作用产生的热中性粒子快速充满二极管间隙，并被电离，可引起二极管间隙短路。     

Pt-SDB疏水催化剂应用于氢-水同位素交换的实验研究

采用气?液逆流方式对苯乙烯-二乙烯基苯共聚物担载金属铂(Pt-SDB)疏水催化剂应用于HD(g)/H2O(l)体系的氢同位素交换进行了实验室规模的中试实验研究;;对该实验系统和Pt-SDB的催化性能作出了评价;;得出了Pt-SDB的总体积传质系数Kya值和各种工艺条件。实验结果表明:当氢气流速为0.2m/s、温度为65℃时;;Pt-SDB与亲水性金属填料按1∶4的体积比混合装柱的Kya平均值达到41.5mol·m?·s?。     

Effect of different ion beam energy on properties of amorphous carbon film fabricated by ion beam sputtering deposition (IBSD)

Amorphous carbon (a-C) films were fabricated by ion beam sputtering technique. The influence of sputtering ion beam energy on bonding structure, morphologic, mechanical properties, tribological properties and corrosion resistance of a-C films are investigated systematically. Morphology study shows that lowest surface roughness exists for mid-ion beam energy. Improved adhesion is observed for the films that are prepared under high ion beam energy, attributed to film graphitization, low residual stress and mixed interface. Relatively, a-C films prepared with ion beam energy of 2 keV exhibits optimum sp³ bond content, mechanical properties and corrosion resistance. It is found that the wear rate of DLC films decrease with increased ion beam energy in general, consistent with the varied trend of the H/E value which has been regarded as a suitable parameter for predicting wear resistance of the coatings. The correlation of the sp³ bond fraction in the films estimated from Raman spectroscopy with residual stress, nanohardness and corrosion resistance has been established.     

Investigation of variable aperture on the performance and lifetime of ion thruster

Beam flatness is an important parameter that determines the performance and the lifetime of a gridded ion thruster.To improve the beam flatness of the 30 cm (LIPS-300) ion thruster,variable aperture ion optics that adapts to the decreasing ion density as the radius increases is proposed.It is the ion optics that the screen grid surface is divided into several zones,where the aperture diameter in each zone is determined by the ion density and the electron temperature upstream of the screen grid.The beam current density in the central area is artificially reduced.A particle in cell-Monte Carlo collision model is applied in this work to investigating the effect of variable aperture on the perveance and the maximum beam current per aperture by simulating the extraction,focusing and acceleration processes of ions.Taking into account the engineering implementability,the screen grid surface is divided into four zones.The hole diameter in each zone is decreased from 1.95 mm to 1.8 mm,1.9 mm,1.8 mm and 1.7 mm,respectively.The simulation results show that the maximum ion density in the center area of grid is decreased by 10.6％ and 6.99％,while it is increased by 6.49％ and 22.3％ in the edge region,respectively.The beam flatness of the variable aperture ion optics is improved from 0.69 to 0.88.The erosion rate is decreased by 31.9％,but the total beam current is also decreased by 7.15％.The simulation results can provide a valuable reference of the development of the ion thruster.     

Influence of the residual oxygen in the plasma immersion ion implantation (PI3) processing of materials

In this work, we investigated the effects of the contaminants present in the vacuum chamber of the PI3 system, in particular, the residual oxygen, which results in the formation of the oxide compounds on the surface and hence is responsible for the high implantation energies required to achieve reasonably thick treated layers. We used a mass spectrometer (RGA) with a quadruple filter to verify the composition of the residual vacuum and pressure of the elements present in the chamber. Initially we found a high proportion of residual oxygen in a vacuum with a pressure of 1 × 10⁻³ Pa. Minimizing the residual oxygen percentage in about 80%, by efficient cleaning of the chamber walls and by improving the gas feeding process, we mitigated the formation of oxides during the PI3 process. Therefore we achieved a highly efficient PI3 processing obtaining implanted layers reaching about 50 nm, even in cases such as an aluminum alloy, where is very difficult to nitrogen implant at low energies. We performed nitrogen PI3 treatment of SS304 and Al7075 using pulses of only 3 kV and 15 × 10⁻⁶ s at 1 kHz with an operating pressure of 1 Pa.     

Influence of anode temperature on ignition performance of the IRIT4-2D iodine-fueled radio frequency ion thruster

This paper reports the ignition performance of the iodine-fueled radio frequency (RF) ion thruster (IRIT) at different anode temperatures (${T}_{{\rm{a0}}}$). The experimental results show that the anode temperature plays important role on the ignition process of the IRIT. There were two characteristic temperatures related to the anode: the minimum ignition temperature (${T}_{{\rm{i0}}}$) and the stable ignition temperature (${T}_{{\rm{is}}}$), which were much lower than the pipeline temperature and the storage tank temperature. At ${T}_{{\rm{a0}}}$ < ${T}_{{\rm{i0}}},$ it failed to discharge. When ${T}_{{\rm{i0}}}$ ≤ ${T}_{{\rm{a0}}}$<${T}_{{\rm{is}}},$ it was ignited with dramatical oscillations. At ${T}_{{\rm{a0}}}$ ≥ ${T}_{{\rm{is}}},$ the discharge was stable in a large anode temperature range. The analysis showed that the different discharge phenomena at different anode temperatures were attributed to the change of iodine flow rate during the process of the iodine deposition-clogging and sublimation-clearing inside the thruster. The research helps improve the preheating design of the iodine-fueled electric thruster.     

Influence of SHI irradiation on the formation of buried SiC

Silicon carbide (SiC) precipitates buried in Si(1 0 0) substrates were synthesized by ion implantation of 50 keV and 150 keV C⁺ ions at different fluences. Two sets of samples were subsequently annealed at 850 °C and 1000 °C for 30 min. Fourier transform infrared (FTIR) spectroscopy studies and X-ray diffraction (XRD) analysis confirmed formation of β-SiC precipitates in the samples. Ion irradiation with 100 MeV Ag⁷⁺ ions at room temperature does not induce significant change in the precipitates. It could be interpreted from the FTIR observations that ion irradiation may induce nucleation in Si + C solution created by ion implantation of C in Si. Modifications induced by swift heavy ion irradiation are found to be dependent on implantation energy of C⁺ ions.     

Effect of Metallic Impurities on Oxidation Reaction of Ion Exchange Resin, (II)

The catalytic effect of six metallic impurities on the oxidation reaction of cation exchange resin was investigated. The impurities, which were originally adsorbed onto the resin by an ion exchange method, combined with S present in the functional sulfonic acid group during heat-treatment in a nitrogen atmosphere to give the metal sulfides. The sulfides were subsequently oxidized to metal oxides.

In the case of Pd²⁺, Cu²⁺, Fe²⁺ and Fe³⁺ impurities, their sulfides were easily converted into oxides, which catalyzed the resin oxidation. Their catalytic activities depended on the heat of formation of the catalyst oxides ΔH‘₀; the lower was ΔH’₀, the more active the catalyst was. However, Co²⁺ and Ni²⁺ impurities had relatively low catalytic activities. This was because Co and Ni sulfides slowly changed into oxides, and the main chemical compositions of the impurities were not oxides but sulfides, which had no catalytic effect on the resin oxidation.     

Effect of N and C ion beam bombardment on the optical and structural characteristics of ethylene-norbornene copolymer (TOPAS)

Ion bombardment is a suitable tool to modify the optical properties of polymers. In the present study the effect of ion bombardment on the optical absorption of ethylene-norbornene copolymer (TOPAS) was studied using ultraviolet-visible (UV-Vis) and Raman spectroscopy. Polymer samples were bombarded with 60 keV C⁴⁺ and N⁴⁺ ion beams to various fluences ranging from 1.0 × 10¹³ to 1.0 × 10¹⁶ cm⁻². The indirect and direct band gaps have been determined. The values of direct band gaps have been found to be greater than the corresponding values of the indirect band gaps. Activation energy has been investigated as the function of ion fluences. The number of carbon atoms per conjugated length is determined according to modified Tauc’s equation. The correlation between the optical band gap, activation energy for optical transition and the number of carbon atoms per conjugated length as well as chemical structure changes induced by ion beams irradiation have been discussed in the case of ethylene-norbornene copolymer.