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With the continuous growth of the fourth-generation nuclear reactor, the oxidation of irradiated graphite (i-graphite) has become a great concern worldwide in recent years, not only for the far-reaching significance in the treatment of i-graphite waste, but also for the safety evaluation of the reactor. Fission products (FPs) and activation of impurities are generated in i-graphite during reactor operation and inevitably released as radioactive dust when i-graphite is oxidized. The investigation of the binding mechanism between nuclides and graphite dust is vital for further separating procedures of off-gas decontamination. Herein, the mechanism of FP release during the oxidation of High-Temperature Gas-Cooled Reactors’ matrix graphite was explored with Strontium (Sr) as an example. The Sr-loaded matrix graphite was prepared by impregnation and characterized by secondary ion mass spectrometry (SIMS), X-ray powder diffraction (XRD), scanning electron microscope-energy dispersive spectrometer (SEM-EDS), and Raman spectra. The released Sr chemical speciation was extrapolated as SrCO3 through the investigation of the temperature and air flow rate effects on oxidation products. Additionally, the main morphology of the released fragment was identified as SrCO3 clusters anchored at the edge of graphite. The ab initio calculations revealed the mechanism for the anchoring of SrCO3 at the edge of graphite via adsorption. These findings provide a novel understanding of Sr-releasing behavior when i-graphite is oxidized.

Owing to the limitation of a large genome size (~13 Gb), the genetic and gene mapping studies on faba bean (Vicia faba L.) are lagging far behind those for other legumes. In this study, we selected three purified faba bean lines (Yundou 8137, H0003712, and H000572) as parents and constructed two F2 populations. These two F2 populations, namely 167 F2 plants in Pop1 (Yundou 8137×H0003712) and 204 F2 plants in Pop2 (H000572×Yundou 8137), were genotyped using a targeted next-generation sequencing (TNGS) genotyping platform, and two high-density single nucleotide polymorphisms (SNP) genetic linkage maps of faba bean were constructed. The map constructed from Pop1 contained 5 103 SNPs with a length of 1 333.31 cM and an average marker density of 0.26 cM. The map constructed from Pop2 contained 1 904 SNPs with a greater length of 1 610.61 cM. In these two F2 populations, QTL mapping identified 98 QTLs for 14 agronomic traits related to the flowers, pods, plant types and grains. The two maps were then merged into an integrated genetic linkage map containing 6 895 SNPs, with a length of 3 324.48 cM. These results not only lay the foundation for fine mapping and map-based cloning of related genes, but can also accelerate the molecular marker-assisted breeding of faba bean.