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The radiolytic behaviors of aqueous ammonia solutions under γ-ray irradiation were investigated, focusing on several factors, including initial ammonia concentration, absorbed dose, and H3BO3 concentration. The main species including ammonia, H2O2, nitrogen oxides, and H2, were quantitatively analyzed. The results revealed the significant influence of the initial ammonia concentration on the radiolytic behavior of the aqueous ammonia solution. The existence of ammonia in the solution exhibited suppression of the concentrations of H2O2 and O2. Furthermore, the radiolysis of aerated aqueous ammonia solution led to the formation of nitrogen oxides (NO2− and NO3−). This process was driven by multiple oxidation reactions, in which O2 and ·OH played crucial roles. Interestingly, the addition of H3BO3 provided protection to ammonia during γ irradiation, while the concentration of H2O2 was increased. [ABSTRACT FROM AUTHOR]

In this work, the effects of the tungsten (W) converter and molybdenum target thickness on the 99Mo yield in the production of 99Mo via 100Mo(γ, n)99Mo photonuclear reaction were studied. The FLUKA program was applied to simulate the optimal size of the targets for the production of 99Mo under 50 MeV electron conditions, where the thicknesses of the W and Mo targets were 0.3 and 1.4 cm, respectively. The relative error between the calculation and the experimental results was less than 8%. The process of irradiating natural (natMo) and enriched (100Mo) molybdenum targets using electrons with a 1 mA average beam current was further simulated. The specific activity of enriched 100Mo is nearly ten times higher than that of natMo. The use of 100Mo targets also produces fewer radioactive impurities. This study provides a guidance on the size of W conversion and molybdenum targets, as well as the selection of molybdenum species, when producing 99Mo via photonuclear reaction. [ABSTRACT FROM AUTHOR]

A mathematical model of co-decontamination process (1A) containing U(VI), Pu(IV), Zr(IV), and Ru(III) was developed with a high-performance Iteration of Extraction Equilibrium (ITEE) algorithm. ITEE algorithm not only guarantees the positive solution set but also possesses better computational efficiency than L-BFGS-B and fsolve algorithms. This model was used to study the effects of the HNO3 concentration and the location of the feed stage on the extraction and decontamination efficiencies. The results show HNO3 is beneficial to the extraction of U, Pu, and Zr. More extraction stages boost the extraction of U and Pu into the organic phase. [ABSTRACT FROM AUTHOR]