The partitioning and transmutation technology (P&T) is an important methods for the safety, efficiency and sustainable development of nuclear energy. The extraction separation method is a research hotspot in the aspect of “separation”. The diglycolamides have shown good extraction performance and selectivity to trivalent lanthanides/actinides, and have been widely studied in this aspect. In this paper, N, N′-dimethyl-N, N′-dioctyl diglycolamide (DMDODGA) was synthesized and the complexes were characterized by 1H NMR titration, Luminescence emission spectroscopy and other spectroscopic methods. The stable structure of the complexes in the gas phase were obtained through DFT. The interaction and coordination properties between the ligand and Ln(III) were analyzed by means of IGMH, EDA and ETS-NOCV methods. The results show that lanthanides with DMDODGA mainly form 1:3 complexes, and the coordination mode is electrostatic interaction with some covalency. For light lanthanides, the interaction mainly occurs between the 5d orbitals of the lanthanide and the 2p orbitals of O in DMDODGA, while for heavy lanthanides, it mainly involves the 4f orbitals of the lanthanide and the 2p orbitals of O. The coordination covalency between DMDODGA and heavy lanthanides is stronger, so the complexes of DMDODGA with heavy lanthanides is more stable.

Uranium recovery from acidic nuclear effluents remains challenging because many solid adsorbents rely on complex multi-step synthesis or covalent functionalization, limiting scalability and practical deployment. Herein, a facile and scalable solid-phase molecular self-assembly (SPMSA) strategy is developed to engineer supramolecular sheets for U(VI)adsorption. The sheets are fabricated by adding aqueous poly7(diallyldimethylammonium chloride) (PDADMAC) and poly(sodium 4-styrenesulfonate) (PSS) solutions into octyl(phenyl)-N,N-diisobu-tylcarbamoylmethylphosphine oxide (CMPO) under stirring, inducing liquid-solid phase separation to form a CMPO-impregnated precipitate that can be readily compressed into supramolecular sheets, termed PP-C. The PP-C sheets are readily scalable, and show stable U(VI) adsorption over a broad acidity range, with batch preparation demonstrated at the hundred-gram scale and potential for further expansion. Spectroscopic analyses indicate that U(VI) adsorption is mainly associated with CMPO coordination through phosphoryl and carbonyl donor groups, with additional electrostatic interactions from PSS sulfonate groups. Benefiting from these combined interactions, PP-C sheets exhibit a high equilibrium adsorption capacity of 1092 mg center dot g-1 at 40 g center dot L-1 U(VI), and maintain strong selectivity in the presence of 100-fold excess of competing ions. gamma-irradiation up to 200 kGy and adsorption-desorption cycling tests further demonstrate radiation tolerance and preliminary regenerability. Furthermore, because the SPMSA-based sheet construction relies on broadly applicable supramolecular interactions, PP sheets provide a general platform for encapsulating diverse hydrophobic extractants, enabling tunable separation selectivity via extractant selection. Overall, this work establishes an extractant-impregnated SPMSA strategy that integrates adjustable separation with scalable operations for metal ion separation.

The traditional aqueous-organic biphasic extraction for separating radioactive metal ions faces major challenges due to heavy reliance on volatile organic solvents and the resulting refractory radioactive waste. Herein, we propose a customizable, sustainable, and efficient separation strategy for radioactive ions by using liquid-liquid phase separation (LLPS) phenomenon in two coexisting aqueous phases. Unlike conventional organic extraction systems, the LLPS platform operates without forming a bulk organic extraction phase. The LLPS is formed by sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTAB), and hexafluoroisopropyl alcohol (HFIP) (termed as SCH-extraction system) and enables customized encapsulation of commercial extractants. The selectivity of SCH-extraction system can be precisely tuned by adjusting parameters like the type of extractant and solution acidity, making it highly versatile for various separation scenarios. In simulated high-level liquid waste (HLLW), the strategy achieved the separation factors of UO 2 2 + /Nd3+ reaching 2.33 × 104, outperforming existing methods. This superior efficiency is driven by a dual mechanism: hydrophobic entrapment of metal-extractant complexes and electrostatic attraction to the negatively charged condensate interface. Based on this, a thermodynamic model is proposed, providing rational design principles for optimizing the system for diverse separation applications. This strategy holds significant promise for separating valuable radioactive metal ions.

This study systematically investigates the removal performance of cesium iodide (CsI) using modified kaolin-based adsorbents under various operating conditions. The adsorbents were prepared through a combined modification strategy involving thermal activation, calcium oxide (CaO) incorporation, and subsequent acid leaching. The effects of gas flow rate, adsorption temperature, and environmental atmosphere on CsI capture were systematically evaluated. The physicochemical properties of the adsorbents were characterized using different characterization methods. The results demonstrate that the combined modification strategy significantly enhances both the CsI capture capacity and the chemical stability of the adsorbents. For instance, the adsorption capacity of Kaolin-CaO-C-H reaches approximately 160 mg/g under optimal conditions. These findings indicate that the modification process effectively tailors the pore structure and active sites of the adsorbent, thereby improving its efficiency in capturing volatile cesium during high-temperature volatilization processes.

To address the need for efficient and selective separation of plutonium (Pu) in nuclear fuel reprocessing, four ortho-phenoxy diamide extractants were synthesized based on the proven extraction performance of diamide ligands. The extraction behavior of Pu(iv) in nitric acid media and coordination mechanisms was systematically investigated through combined experimental and theoretical approaches. By rationally tuning steric and electronic effects within the ligand structures, the role of cooperative coordination by multi-oxygen donor in governing Pu(iv) extraction performance was elucidated. The extraction efficiency of Pu(iv) follows the order L2 (ButoBenzoDODA) > L1 (n-OctDODA) > L3 (ClBenzoDODA) > L4 (BenzoDODA). The distribution coefficients of Pu(iv) increase markedly with increasing HNO3 concentration and ligand concentration, and stable 1 : 2 metal-to-ligand complexes are formed during extraction. Compared with various competing metal ions, all ligand systems exhibit a pronounced extraction preference toward Pu(iv), among which L2 shows the best overall performance, achieving a maximum distribution ratio of 12.37 and maintaining good recyclability over multiple extraction-stripping cycles. Density functional theory (DFT) calculations with experimental study reveal that the Pu-O(C[double bond, length as m-dash]O) interactions are mainly electrostatic in nature, with amide oxygen atoms serving as the primary coordination sites and ether oxygen atoms providing cooperative stabilization. The superior extraction performance of L2 is attributed to its more favorable electronic structure, consistent with the experimental observations. Overall, this study clarifies the synergistic roles of steric and electronic effects in Pu(iv) extraction and provides a theoretical and experimental basis for the rational design of high-performance plutonium extractants.

The metallic cladding of spent nuclear fuel rods in nuclear power plants can be safely and efficiently cut using fiber lasers. Therefore, it is of great importance to develop silica fibers capable of transmitting high-power laser in high-radiation environments. However, inherent hydroxyl (OH) and chlorine (Cl) impurities in silica fibers adversely affect their radiation resistance. To fabricate silica fibers with high radiation resistance, this study prepared a series of glass samples with varying Cl/OH content using the Vapor Axial Deposition (VAD) method. The effects of radiation on the optical properties of the samples with different impurity concentrations, along with the underlying mechanisms, were investigated using absorption spectroscopy, photoluminescence spectroscopy, electron paramagnetic resonance (EPR), and photothermal absorption microscopy. Passive delivery fibers with a core diameter of 100 mu m were fabricated using the rod-in-tube method. The influence of OH and Cl impurities on the fiber attenuation, laser delivery performance, and temperature rise coefficient was studied. The results indicate that the radiation resistance of medium-OH, Cl-free fibers is far superior to that of low-OH, high-Cl fibers. This research provides a reference for applying high power laser technology in high-radiation scenarios.

Reprocessing of MOX fuel is a critical technology for sustainable nuclear energy. Its primary objectives include the extraction of reusable uranium and plutonium resources, and recovering long-lived actinide elements to provide conditions for transmutation disposal and eliminate long-term radioactive risks brought by nuclear energy development. The aqueous reprocessing technology has formed a relatively mature process technology in the reprocessing of ordinary thermal reactor spent fuel, so it is a practical route for the MOX fuel reprocessing. However, due to the significantly higher burnup, plutonium content, and fission product content of spent MOX fuel compared to thermal reactor spent fuel, there are substantial differences in the processes of shearing and dissolution, uranium/plutonium separation, as well as in radiation protection, criticality safety, and waste management. Consequently, the development of reprocessing technologies for spent MOX fuel is both highly significant and challenging. Currently, several countries such as France, Russia, India, and China, have initiated research on reprocessing technologies for high-burnup MOX fuel. This paper reviews the global research and practical experiments in spent MOX fuel reprocessing, with a focus on the chemical separation processes, and also provides a brief discussion on shearing and dissolution, backend processes, and waste disposal. As MOX fuel is the most mature fuel type for fast reactors, the current status of aqueous reprocessing technology for MOX fuel is mainly introduced.

In the PUREX process, organic salt-free reductants are employed in uranium-plutonium separation and subsequent purification stages to minimize secondary waste generation during nuclear fuel reprocessing. This practice inevitably yields acidic liquid waste streams containing residual reductant and excess nitric acid. Methylhydrazine (MMH), an organic salt-free reductant independently developed in China, has been introduced for these applications. Efficient removal of unreacted MMH from such radioactive acidic waste is essential to ensure process stability and facilitate safe, compliant disposal of high-level liquid waste. Conventional oxidative destruction methods such as those based on sodium nitrite or nitrogen oxides are limited by several critical drawbacks: they introduce salts into the waste matrix, generate substantial quantities of radioactive off-gas, complicate downstream waste solidification and volume reduction, and pose elevated operational hazards. To overcome these limitations, this study develops and evaluates a Ru/C-catalyzed decomposition pathway for MMH in nitric acid media. Through comprehensive product analysis, kinetic and mechanistic investigation of the catalytic reaction, and systematic assessment of catalyst deactivation pathways, we identify nitrogen (N2), nitric oxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O) as the principal gaseous decomposition products, and methanol (CH3OH) and methylamine (CH3NH2) as the dominant liquid-phase species. The reaction mechanism and principal causes of Ru/C deactivation including nitric acid-induced metal leaching and surface oxidation are elucidated. These findings not only validate the technical feasibility of MMH integration into industrial PUREX operations but also provide a scientifically grounded basis for scaling up and optimizing salt-free reductant destruction processes.

This study systematically investigates the removal performance of cesium iodide (CsI) using modified kaolin-based adsorbents under various operating conditions. The adsorbents were prepared through a combined modification strategy involving thermal activation, CaO addition, and subsequent acid leaching. The effects of gas flow rate, adsorption temperature, and atmosphere on CsI capture were systematically evaluated. The physicochemical properties of the adsorbents were characterized using multiple techniques. The results demonstrate that the combined modification strategy significantly enhances both the CsI capture capacity and the chemical stability of the adsorbents. For instance, the adsorption capacity of Kaolin-CaO-C-H reaches approximately 160mg/g under optimal conditions. These findings indicate that the modification process effectively tailors the pore structure and active sites of the adsorbent, thereby improving its efficiency in capturing volatile cesium during high-temperature volatilization processes.

Spent nuclear fuel reprocessing plays a pivotal role in achieving a closed nuclear fuel cycle. However, traditional research approaches face significant obstacles due to the highly radioactive environment, limited availability of experimental data, and the inherent complexity of the underlying mechanisms. Artificial intelligence (AI), with its strength in extracting intricate patterns and making predictions from sparse data, offers promising solutions to these longstanding challenges. Recent advancements have demonstrated the potential of AI in diverse domains, including image recognition, process modeling, materials discovery, process control, data analytics, and safety assessment. By addressing the limitations of conventional methods in data handling and mechanistic modeling, AI enhances system safety and operational efficiency under extreme conditions. Furthermore, it complements traditional physics-based approaches, paving the way for transformative research paradigms. As the volume of accessible data grows and algorithms continue to evolve, AI applications in spent fuel reprocessing are expected to expand—enabling fully integrated, self-optimizing control systems and proactive safety monitoring. These developments promise to significantly reshape the landscape of nuclear fuel reprocessing technologies.

Diglycolamide ligands show good extraction performance for Ln(III) and An(III) and have good application prospects in the field of HLLW separation. In this study, two asymmetric diglycolamides with ethyl branches at the α and β positions of long alkyl chains were synthesized through a microwave-assisted silane-mediated improved amidation method: N,N'-dimethyl-N,N'-bis(1-ethylhexyl) diglycolamide (DMDEHDGA, L1) and N,N'-dimethyl-N,N'-bis(2-ethylhexyl) diglycolamide (DMD2EHDGA, L2). The ligands' extraction and coordination behaviors were studied using extraction and spectroscopic titration, and the electronic structures and bonding properties of the ligands and complexes were analyzed using density functional theory (DFT). The results show that both ligands have better extraction performance for heavy Ln(III), and the extraction performance of L1 is stronger than that of L2. The complexes exhibit a non-centrosymmetric structure, and the branched chain of L1 directly affects the coordination. The complexes are formed through electrostatic interactions with covalent bond characteristics between the ligands and Ln(III). Combined with relevant conclusions regarding DMDODGA, an isomer of the ligand with a linear substituent, it was found that the addition of a branched chain provides varying degrees of steric hindrance and electron-donating effects, leading to differences in extraction and coordination properties among ligands with different structures.

Imidazolium cation-based ionic liquids (ILs) are promising optimized components for lithium-ion batteries (LIBs) electrolytes to improve their performances. Besides, in the recycling of lithium from spent LIBs, imidazolium ionic liquids can serve as extractants for other metal ions. The study of the separation of lithium and imidazolium ions will promote the application of ILs in LIBs. Electrodialysis is an environmentally friendly method for separating Li+ and [Bmim]+ cations without the need for additional chemical reagents. In order to study the separating mechanism of monovalent selective cation exchange membrane for Li+ and [Bmim]+, this paper reported the membrane pore size by Ferry Faxen equation, the selectivity and the diffusion coefficient of the two ions in membrane, and the permselectivity of membrane at different current densities through electrodialysis process and discussed the process of electrodialysis separation of the two ions using Nernst-Planck equation. The results indicate that the spatial size of [Bmim]+ hydrated ion is close to or larger than the membrane pore size, and [Bmim]+ ion has a strong interaction with the sulfonic acid groups on the surface of the membrane. The two reasons above lead to the effective separation of two ions.

Utilizing laser technology for the dismantling and cutting of fast reactor assembly represents a viable nuclear fuel reprocessing technology for future applications. The commonly adopted procedure involves removing the hexagonal tube and end structures of the assembly without compromising the integrity of the fuel rods, which are then cut into short segments. Therefore, mastering the laser cutting parameters that ensure high-quality cuts of the hexagonal tube while minimizing damage to the internal component rods is essential. This study investigates the impact of laser cutting parameters on the quality of cuts in stainless steel hexagonal tubes. Optimal conditions-3.5 m/min cutting speed, -1.5 mm focal position, 4800 W power, and nitrogen at 15 MPa-produced minimal kerf width (0.438 mm), surface roughness (4.21 mu m), and slagging length (0.206 mm). These findings highlight the importance of precise parameter control in laser cutting for nuclear applications, offering significant improvements in efficiency and safety for fast reactor fuel reprocessing.

Diglycolamides show good selectivity for trivalent lanthanides and actinides and have good application prospects in the treatment of high level liquid waste (HLLW). In this study, two asymmetric diglycolamides with methyl groups at the α-position and β-position of the branched chains were synthesized through a microwave-assisted silane-mediated method: N,N'-dimethyl-N,N'-di(1-methylheptyl) diglycolamide (DMDMHDGA, L1) and N,N'-dimethyl-N,N'-di(2-methylheptyl) diglycolamide (DMD2MHDGA, L2). The extraction performance of these two ligands for Ln3+ was tested in the HNO3 system. The coordination properties of the ligands with Ln3+ were studied by spectroscopy, and the coordination properties of the complexes were analyzed by density functional theory (DFT). Both ligands have better extraction performance for heavy Ln3+ over light Ln3+, while the extraction ability of L2 to light Ln3+ is relatively stronger than that of L1. The ligands form 2:1 complexes with Ln3+, which has a noncentrosymmetric octahedral structure. The ligands primarily form complexes with Ln3+ through electrostatic interactions with covalent characteristics. Differences in the positions of the branched chains lead to steric hindrance and electron-donating effects, thereby influencing their extraction and coordination behaviors toward Ln3+.

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.

The simulated spent nuclear fuel segment were oxidized at 500 degrees C, which is very important to the voloxidation. The results demonstrate that the average of oxidation rate is 0.395 cm/hr. Besides, the oxide layer formed between the pellet and the hull caused that oxidation carried out along the axial direction of the segment, and the oxidation of the segment meet the crack-spallation model. Finally, by measuring the oxidation rates at different oxygen volume fractions, it was confirmed that the simulated spent fuel segments oxidation macroscopically manifests as a first-order reaction. In addition, the rate-limiting step mainly affected by oxygen concentration.

Hydroxylamine nitrate (HAN) and hydrazine nitrate (HN) are commonly found in radioactive waste solutions in nuclear fuel reprocessing, and their efficient removal is essential for waste treatment processes. In this study, six activated carbon carriers were selected to prepare Ru/AC catalysts for the simultaneous catalytic decomposition of HAN and HN, with the aim of exploring the effect of carrier properties on catalytic performance. The catalyst’s activity was evaluated in a batch reaction unit, and its structural properties were characterized using N2 physical adsorption, XRD, SEM, and TEM techniques. The results revealed that the catalyst’s activity was primarily determined by the carrier’s particle size and specific surface area. Additionally, corrosion-induced damage to the pore structure and Ru loss were identified as the main factors responsible for catalyst deactivation. This study highlights the importance of optimizing carrier structure to enhance the activity and stability of Ru/AC catalysts.

Fast-neutron reactors are an important representative of Generation IV nuclear reactors, and due to the unique structure and material properties of fast reactor fuel, traditional mechanical cutting methods are not applicable. In contrast, laser cutting has emerged as an ideal alternative. However, ensuring the stability of optical fibers and laser cutting heads under high radiation doses, as well as maintaining cutting quality after irradiation, remains a significant technical challenge. Here, we study the performance changes in optical fibers exposed to a total radiation dose of 105 Gy, focusing on power transmission and thermal characteristics. By integrating irradiated optical fibers with irradiated laser cutting heads, simulated cutting experiments on the hexagonal tubes of spent fuel from fast reactors (fast reactor simulation assembly) were conducted. Critical cutting quality parameters, including kerf width, surface roughness, and slagging length, were analyzed. The results indicate that, while the power transmission performance of irradiated optical fibers shows slight degradation, its impact on cutting quality is minimal. High-quality cutting can still be achieved under optimized parameters. This study confirms the feasibility of laser cutting technology in high-radiation environments and provides essential technical support for its application in nuclear fuel reprocessing.