Pyrochemical reprocessing has emerged as a crucial alternative to conventional hydrometallurgical methods for the reprocessing of spent nuclear fuel (SNF), particularly for high-burnup SNF from advanced reactors. Unlike the Plutonium Uranium Recovery by Extraction (PUREX) process, which encounters challenges with high-burnup SNF, pyrochemical reprocessing facilitates the direct processing of short-cooled fuel through electroreduction and electrorefining in molten salt. This review presents the research advancements in electroreduction and electrorefining within the context of pyrochemical reprocessing of SNF, systematically introducing the latest findings across five key areas: the electroreduction of oxide SNF pellets composed of various materials, anode materials, solid cathode materials, liquid cathode materials, and molten salt systems utilized in the electroreduction and electrorefining processes. Finally, the article summarizes the pressing issues currently facing electroreduction and electrorefining and proposes directions for future research.

This project designed and created a large-scale pyrolysis incineration system that decomposes waste tributyl phosphate/kerosene (TBP/OK) solvent from the plutonium/uranium process (PU-REX) in the nuclear industry. This system consists of a suspension preparation system (SPS), a pyrolysis and ash discharge system (PADS), and a combustion furnace and gas treatment system (CGS). The preparation of a waste TBP/OK emulsified suspension in the SPS, continuous operation experiments of the PADS and CGS, and pyrolysis incineration experiments were conducted. The results show that the SPS achieved the automatic preparation and feeding of emulsified suspensions at 30 kg/h. The PADS decomposed 99.99% of the TBP/OK emulsified suspensions and fixed more than 99% of phosphorus. The CGS burned the pyrolysis gas without diesel oil and purified more than 99.995% of the radioactive nuclides. This system showed great feasibility, stability, continuity, and safety, proving the compatibility between multiple systems of this new design. This paper marks a significant step in pyrolysis incineration technology for the nuclear industry.

In this work, a molecular simulation method was used to study the adsorption of seven combustion products (CO₂, H₂O, SO₂, N₂, O₂, NO and NO₂) on three zeolites with different topological structures (4A, MIF and MOR). Adsorption isotherms of pure components and mixtures at a wide range of temperatures (253–333 K) were calculated using the Monte Carlo method, obtaining equilibrium parameters including the adsorption capacity, adsorption heat and energy distribution. The calculation results indicated that 4A zeolite with more micropores has a stronger adsorption performance for CO₂. The presence of water significantly reduced the CO₂ capture efficiency of the three zeolites, and the CO₂ adsorption amount decreased by more than 80%. Adsorption kinetics was studied using the molecular dynamic (MD) method, MFI and MOR, with channel-type pore structures exhibiting stronger gas diffusion performance, though their separation efficiency was not high. A 4A zeolite has the potential for kinetic separation of CO₂.

Austenitic stainless steel is renowned for its exceptional corrosion and mechanical properties, yet it remains susceptible to localized corrosion, such as pitting in the presence of aggressive ions or/and extreme environmental conditions. Critical pitting temperature (CPT) serves as a key metric for evaluating the susceptibility to pitting corrosion, and its accurate prediction is essential for engineering pitting-resistant alloys. In this work, through optimized feature selection processes, three critical features − standard reduction potential (\({E}_{\max }\)), valence electron (\({{VEC}}_{{sum}}\)), and geometric parameters (\(\lambda\)) − are identified as crucial descriptors for CPT. Utilizing interpretable machine learning techniques, a predictive model for CPT is developed and confirmed via cross-validation, demonstrating superior predictive accuracy. This work not only deepens our understanding of the underlying factors affecting pitting but also facilitates the development of austenitic stainless steel with improved resistance to pitting corrosion.