Iodine is one of the key elements that must be removed from the off-gas systems of nuclear fuel reprocessing. This study systematically investigates the iodine vapor adsorption performance of the metal–organic framework (MOF) material HKUST-1(1-(2-methyl-4-(2-oxopyrrolidin-1-yl)phenyl)-3-morpholino-5,6-dihydropyridin-2(1H)-one), with particle sizes of 100 nm and 20 μm. HKUST-1 samples with varying particle sizes were synthesized via a hydrothermal method. The experimental results show that the 20 μm HKUST-1 exhibits superior crystallinity, a more intact pore structure, and a higher iodine adsorption capacity, reaching 700 mg/g, which is significantly greater than the 300 mg/g capacity of the 100 nm HKUST-1. Kinetic analysis reveals that the adsorption process follows the pseudo-second-order model, with physical adsorption as the predominant mechanism, where iodine molecules are accommodated within the pores. FTIR and XRD further confirm the structural stability of the HKUST-1 framework after iodine adsorption. However, desorption experiments show that iodine molecules are easily volatilized into the air, with a 20% weight loss observed within 10 h and a color change from black to green. The results provide experimental evidence for optimizing the application of HKUST-1 materials in iodine capture and suggest that material modification could enhance the long-term stability of iodine fixation.

In this study, a novel adsorbent, UiO-66-H3IMDC, was successfully prepared by functionalizing UiO-66 with imidazole-4,5-dicarboxylic acid (H3IMDC). The effective functionalization of H3IMDC on UiO-66 was confirmed by powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FT-IR). The relationships between the adsorption of U(VI) on UiO-66-H3IMDC and the contact time, the pH of the solution, as well as the initial concentration of U(VI) were investigated. Additionally, the selective adsorption of U(VI) by UiO-66-H3IMDC and its cyclic regeneration performance were also studied. The results demonstrate that the UiO-66-H3IMDC adsorbent exhibits excellent adsorption performance for uranium in aqueous solutions.

Developing effective iodine capture technologies is critical for both nuclear safety and environmental protection. This study investigates the iodine adsorption properties of ZIF-8, a metal–organic framework (MOF). ZIF-8 samples with varying particle sizes (∼50 nm, 90 nm, 150 nm, and 8 μm) were synthesized and tested for iodine vapor adsorption at 80 °C. Iodine uptake continuously increased with time, reaching 3500 mg/g after 24 h without reaching equilibrium, with no significant dependence on particle size. Structural changes in ZIF-8 were observed, as iodine accumulation led to the breakdown of the framework into an amorphous gel-like substance, representing a previously unreported phase transformation. SEM and XRD characterization confirmed the collapse of the crystalline structure after iodine loading. These results indicate that iodine adsorption in ZIF-8 involves strong chemisorption in addition to physical uptake, causing irreversible framework transformations. This work highlights the influence of particle size and provides important insights for using ZIF-8 in effective radioactive iodine capture.

Al-MOF synthesized based on MOF irradiation stability rules exhibits high stability against β-irradiation and ultra-high thorium adsorption capacity, which proves its huge potential application value in the field of radionuclide adsorption.

The effective adsorption capture of iodine produced in the spent fuel reprocessing is an effective way to avoid the harm of iodine to the ecological environment and human health. In the investigation described herein, a new kind of shaped silicalite-1 all-silica zeolite with a binder which was for direct industrial application other than power was synthesized and tested for iodine adsorption performance. Although the existence of binder in shaped silicalite-1 all-silica zeolite, it still exhibited high iodine adsorption capacities of 507 mg g-1, which was superior to inorganic adsorbents such as silver-containing zeolite mainly used currently, and was comparable with that of power silicalite-1 reported previously. Moreover, the shaped silicalite-1 all-silica zeolite could be cyclic utilization due to its reversible adsorption. All these show that the shaped silicalite-1 all-silica zeolite provides the possibility for the application of iodine adsorption in industrial post-processing condition

The reduction stripping behavior of Pu(IV) from 30%TBP/OK with hydroxysemicarbazide (HSC) was investigated, and the separation efficiency of HSC and DMHAN-MMH for U/Pu partitioning in Purex process was compared. The results show that HSC can effectively realize the separation of Pu from U; using mixer-settlers to simulate U/Pu separation in 1B bank of PUREX, from 16-stage counter current extraction experiment (in which 6 stages for supplemental extraction, 10 stages for stripping) with flow rate ratio (1BF : 1BX : 1BS) = 4: 1 : 1 in 1B contactor, good result was achieved that the yields are both more than 99.99% for uranium and Pu, the separation factor of plutonium from uranium (SFPu/U) is 2.8 x 10(4), and separation factor of uranium from plutonium (SFU/Pu) is 5.9 x 10(4). As a stripping reductant, HSC can effectively achieve the separation of Pu from U and the separation effect is nearly the same with DMHAN-MMH, which contributed to replace enough the latter with HSC in the U/Pu separation in Advanced Purex Process Based on Organic Reagent (APOR) process.

The convenient division of aqueous samples into droplets is necessary for many biochemical and medical analysis applications. In this article, we propose the design of a cost-effective droplet generator for potential bio-chemical application, featuring two symmetric tubes. The new droplet generator revisits the relationship between capillary components and liquid flow rates. The size of generated droplets by prototype depends only on generator dimensions, without precisely needing to control external flow conditions or driving pressure, even when the relative extreme difference in flow rate for generating nL level droplets is over 57.79%, and the relative standard deviation (RSD) of the volume of droplets is barely about 9.80%. A dropper working as a pressure resource is used to verify the rapidity and robustness of this principle of droplet generation, which shows great potential for a wide range of droplet-based applications.

The significant differences in the catalytic properties caused by different 'isotopic catalysts' were discovered for the first time. The commonly purchased Fe2O3 is a 'mixture' of different Fe isotopic oxides which means the catalytic effect of Fe2O3 is theoretically a synthetical result of all isotopic compounds. In this work, the differences in catalytic properties of α-Fe2O3 with natural abundance ratio and separated isotopic α-Fe2O3 (α-54Fe2O3, α-56Fe2O3, and α-58Fe2O3) catalyzing thermal decomposition of ammonium perchlorate (AP) were investigated, and are mainly attributed to the difference in the charge distribution of the nuclei of different iron isotopes. The result suggests that isotope effects in different isotopes when utilized as catalysts are caused by nuclear morphology and the nuclear charge distribution. This study will serve as a base as well as an initiation for future studies of the isotopic catalyst.

Spent fuel reprocessing is the main part of the closed recycling of nuclear fuel. The efficient capture of radioactive iodine in spent fuel reprocessing remains a major issue for the safe utilization of nuclear energy. To possibly substitute the silver-containing zeolites of high cost, copper-doped porous silica including microporous silicalite-1 zeolite (denoted as Cu-S-1) and mesoporous SBA-15 (denoted as Cu-SBA-15) different from those of copper-exchanged ones previously reported were investigated for iodine adsorption at moderate temperature. The influence of pore diameter on iodine adsorption was emphatically discussed. Because of the nanosized pore structure, Cu-S-1 and Cu-SBA-15 exhibited high iodine adsorption capacities of 501 mg g-1 and 59 mg g-1, respectively. The iodine adsorption capacity of Cu-S-1 was higher than those of the silver-containing ones reported up to now. Moreover, it was revealed that the microporous structure was more beneficial to adsorb iodine than the mesoporous structure. These copper-doped silica zeolites provide the possibility for the application of iodine adsorption in practical post-processing conditions.

Hydroxyurea(HU) is a reducing and complexing agent that can be used in the PUREX process. Zr is an important fission product in the spent fuel and main element of concern in the nuclear fuel reprocessing. The decontamination of zirconium in the route of plutonium and uranium can be lowered by the complexation of hydroxyurea in the PUREX process. The complexation of Zr(Ⅳ) with hydroxyurea in the nitric acid system was investigated in this work. Under the condition of 0.3 mol/L HNO3, the complex ratio of Zr(Ⅳ) with HU is 1∶8 obtained by Job’s method. Combining with the half-integer method, the apparent stability constants of Zr(Ⅳ) with hydroxyurea are calculated as following: lg K1≈1.59, lg K2≈1.75, lg K3≈1.88, lg K4≈1.98, lg K5≈2.09, lg K6≈2.27, lg K7≈2.51, lg K8≈3.01. Under 1.0 mol/L HNO3, the complex ratio of Zr(Ⅳ) with hydroxyurea is 1∶4, and the apparent stability constants of Zr(Ⅳ) with hydroxyurea are lg K1≈2.33, lg K2≈2.51, lg K3≈2.78, lg K4≈3.31. Under 3.0 mol/L HNO3, the complex ratio of Zr(Ⅳ) with hydroxyurea is 1∶2, and the apparent stability constants of Zr(Ⅳ) with hydroxyurea are lg K1≈2.69 and lg K2≈2.79.

Capturing volatile radionuclide iodine produced in the nuclear industry is a crucial environmental issue. In previous studies, the principal efficient adsorbent for iodine capture was silver-containing zeolite. As silver-containing zeolites are expensive, alternate copper-loaded porous zeolites, including CuCl loaded NaY reduced by H2 (denoted as H2CuY) and CO (denoted as COCuY), were studied for iodine adsorption at moderate temperatures. The current work also discusses the influence of copper valency on iodine adsorption. Due to the copper sites and nanosized pore structure, H2CuY and COCuY showed high iodine adsorption capacities of 450 and 219 mg/g, respectively. The iodine adsorption capacity of H2CuY was higher than that of silver-loaded zeolites. Moreover, H2CuY and COCuY adsorbed volatile iodine through a chemical mechanism involving the copper sites of different valencies, and the Cu0 was more effective in adsorbing iodine than Cu+. These copper-loaded zeolites with strong chemical interactions with iodine and high iodine adsorption capacities provided the possibility for iodine adsorption application in the nuclear industry.

采用氨基羟基脲(HSC)的硝酸水溶液研究了从30％(体积分数,下同)TBP/煤油中还原反萃高浓度四价钚(Pu(Ⅳ))的性能,并与羟胺-肼(HAN-HN)、N,N-二甲基羟胺-单甲基肼(DMHAN-MMH)在钚净化浓缩循环中反萃行为进行了对比.结果表明:在一定HSC浓度下,适当延长相接触时间、减小相比(o/a)、降低酸度和提高温度,均有利于Pu(Ⅳ)的还原反萃.HSC作为还原反萃剂,可以有效实现30％TBP/煤油中高浓钚的反萃,反萃效果较其它几种还原剂更好,有望在先进二循环流程的钚净化浓缩工艺中得到应用.

钌是重要的裂变产物之一,在核燃料后处理的铀纯化循环中通过预处理工艺改变钌的化学形态可改进钌的净化效果.采用氨基羟基脲(HSC)作为预处理工艺中的还原剂,研究还原剂浓度、预处理酸度、预处理温度等因素对钌的预处理效果的影响,并进行铀纯化循环萃取净化工艺的台架试验验证.结果 表明:氨基羟基脲作为预处理试剂对提高铀纯化循环中钌的净化系数具有明显作用;在铀纯化循环台架温试验中钌的净化系数为1 455,在PUREX流程中具有良好的应用前景.

进行了氨基羟基脲(HSC)的硝酸水溶液对30％(体积分数,下同)磷酸三丁酯(TBP)/煤油中高浓度四价钚(Pu(Ⅳ))的还原反萃行为研究,并采用试管串级实验对HSC在钚净化浓缩循环中反萃段工艺进行了验证.结果表明:HSC能有效地实现有机相中高浓Pu(Ⅳ)的反萃;采用13级逆流反萃试管串级实验(还原反萃段10级,补充萃取段3级),对PUREX流程钚净化浓缩反萃段工艺进行了验证,在相比(2BF:2BX:2BS)为1:0.25:0.15的条件下,Pu的收率为99.99％;钚中去铀的分离因子SF(U/Pu)=3.7×105.HSC作为还原反萃剂,可以实现30％TBP/煤油中高浓度Pu(Ⅳ)的有效反萃,在钚净化浓缩循环工艺中有良好的应用前景.

采用C80微量热仪分别测定了亚硝酸与肼或羟胺的反应热,得到了亚硝酸与肼以不同摩尔比反应时的摩尔反应热:亚硝酸与肼的摩尔比大于2时,消耗单位摩尔肼的反应放热量 ΔE1=284.4 kJ/mol;亚硝酸与肼的摩尔比小于1时,消耗单位摩尔亚硝酸时的反应放热量 ΔE2=166.7 kJ/mol;亚硝酸与肼的摩尔比介于1和2之间时,消耗单位摩尔肼的反应放热量介于 ΔE1和 ΔE2之间.得到了亚硝酸与羟胺以不同浓度比进行反应时的反应热:亚硝酸过量时,消耗单位羟胺的反应放热量为 ΔE4=200.0 kJ/mol;羟胺过量时,消耗单位亚硝酸时的反应放热量为 ΔE5=194.9 kJ/mol.基于获得的亚硝酸与肼或羟胺的反应热数据,对核燃料后处理工艺流程中1BP调料过程中的温度升高情况进行了计算分析,并通过工艺实验进行了验证.

Hydroxylamine nitrate is the reduction of plutonium stripping unit (2B) .T he simulation of one-stage of 2B was studied in this paper ,a new model and algorithm on reductive stripping of plutonium with hydroxylamine nitrate from 30% TBP/n-dodecane were proposed based on iterative model ,and a computer program for simulating the sin-gle stage was developed .The calculation results were compared with the data obtained from literature .The results show that the experimental results agree well with the cal-culation results by the model ,and the accuracy of the model is better than that of litera-ture model .The influence of time span of calculation on the accuracy was analyzed .

The effect factors on reductive stripping of high content plutonium with hydroxyl‐amine nitrate(HAN) from 30% TBP/OK were studied in this paper .The results show that prolonging the contact time ,reducing HNO3 concentration and increasing the temperature all are favorable to reductive stripping of Pu (Ⅳ) .Although increasing the HAN concentration is also in favor of reductive stripping of Pu (Ⅳ) ,it’s not visible for increasing percentage of reductive stripping Pu when the HAN concentration is more than 0.4 mol/L .Increasing the hydrazine concentration is also in favor of reductive stripping of Pu (Ⅳ) ,but the percentage of reductive stripping Pu is reduced with increasing of the hydrazine concentration w hen the hydrazine concentration is more than 0.2 mol/L .The effect of nitrate ion concentration on reductive stripping of Pu (Ⅳ ) is greatly and the percentage of reductive stripping reduces with the increasing of concentration of plutonium . The process of reductive stripping for high content plutonium is affected significantly by the distribution of plutonium between liq‐uid and organic .

Background: Plutonium was one of the most radionuclides and the reducing of Pu(IV) had been researched extensively. It was one of the main research directions that Pu(IV) was reduced by hydrazine derivatives. Purpose:The direction of the study of the separation of Np(VI) from Pu(IV) could be pointed out and crucial basic data for it could be obtained by the study of the quantitative structure-activity relationships (QSAR) between the half-reaction times of reducing Pu(IV) and their physicochemical parameters. Methods: 3D structure of hydrazine derivatives was optimized and their energy was calculated by density functional theory (DFT) with B3LYP method and 6-311+(3d,3p) basis set and the most stable structure was obtained. The physicochemical parameters such as hydrophobic parameters etc. that can describe the structure were gained by HyperChem. Results: The interconnectedness between the half-reaction times and their physicochemical parameters was analyzed, and the QSAR equation with a good correlation is obtained, finally. Conclusion: The result showed that the hydrophobic parameter was the most important factor affecting the reduction rate of Pu(IV) by hydrazine derivatives, and was negatively correlated with Pu(IV) reduction rate.

PUREX process was the only commercialized hydrometallurgy reprocessing process,which could recycle the uranium and plutonium in spent nuclear fuel successfully. Pu(Ⅲ)should be oxidized to Pu(Ⅳ)before it was extracted into TBP-diluent in plutonium purification cycle of PUREX process.Meanwhile,the reductants in 1BP feed,such as hydroxamine,hydrazine and U(Ⅳ)should be oxidized.Previous research showed that N2 O4 was an excellent and salt-free oxidant to the reductants.Therefore,oxidation of the reducta-nts by nitrous gases mentioned above were studied in glass packed column in a gas liquid con-current flow model.The results show that the dosage of N2 O4 ,the reaction time in column and reaction temperature have significant impact on the oxidation of the reductants.When the residence time of the 1BP feed in glass column is 3 min and the dosage of N2 O4 is 1.2 times higher than that of the total reductants,more than 99.9% of reductants are oxidized, and the oxidation rate of Pu(Ⅲ)is also higher than 99.9%.

The influences of the time of phase contact,the phase ratio,the concentration of HNO3 on the extraction of Zr in nitric acid solution and the influences of flow ratio,the con-centration of HNO3 in 2AF,the stage number of the extraction and scrubbing sections and the concentration of uranium in 2AF on counter current extraction process have been studied in this work.The results show that there is a significant impact for the removal of Zr by flow ratio (2AF∶2AX),the concentration of HNO3 in 2AF,the stage number of the scrubbing section.Though there is a limited impact for the removal of Zr by the concentration of urani-um in 2AF.The better extraction technology was verified through bench scale test.The decontamination factor (DF)of Zr is about 1 63,much higher than the design value.