[en] Hydrolysis properties of metal cations and fundamental principles of the potentiometric titration of free acid in aqueous solutions containing metal cations were described. The published papers and reports for the alkalimetric and acidimetric titration of free acid were surveyed, and the applicability of these titration methods to the uranium and/or plutonium solutions were discussed. This technical report also includes the various results obtained from the authors' researches to establish the alkalimetric and acidimetric titration methods for the determination of free acid in nitric acid solutions containing uranium and/or oxalic acid, and aluminum. The procedure manuals used in chemical processes and the newly prepared manuals based on the authors' researches are appended. (author). 26 refs., 54 figs

[en] For the purpose of developing the future nuclear fuel recycle system, the design study of the advanced nuclear fuel recycle system is being conducted. This report describes intermediate accomplishments in the conceptual system study of the advanced nuclear fuel recycle system. Fundamental concepts of this system is the recycle system using molten salt which intend to break through the conventional concepts of purex and pellet fuel system. Contents of studies in this period are as follows, 1)feasibility study of the process by Cd-cathode for nitride fuel, 2)application study for the molten salt of low melting point (AlCl3+organic salt), 3)research for decladding (advantage of decladding by heat treatment), 4)behavior of FPs in electrorefining (behavior of iodine and volatile FP chlorides, FPs behavior in chlorination), 5)criticality analysis in electrorefiner, 6)drawing of off-gas flow diagram, 7)drawing of process machinery concept (cathode processor, vibration packing), 8)evaluation for the amounts of the high level radioactive wastes, 9)quality of the recycle fuels (FPs contamination of recycle fuel), 10)conceptual study of in-cell handling system, 11)meaning of the advanced nuclear fuel recycle system. The conceptual system study will be completed in describing concepts of the system and discussing issues for the developments. (author)

[en] The influence was studied of the concentrations (at room temperature) of di-n-butylphosphoric acid (DBP) and a mixture of 26% of di-(2-methylbutyl)- and 74% of di-(3-methylbutyl)phosphoric acids (D2, 3MBP) (range of concentrations of the acids ∼0.2·10^-3 35·10^-3 mole/liter), nitric acid (0-12 mole/liter), nature of the organic solvent (OS-CCl₄ and n-decane), the presence in the OS phase of a neutral organophosphorus extractant (S-TBP or a mixture of 26% of tri-(2-methylbutyl)- and 74% of tri-(3-methyl butyl) phosphates (T2, 3MBP)) on the distribution of DBP and D2, 3MBP in water-HNO₃-OS-S two-phase systems. It was found that the interphase distribution of the acids (HA) studied can be described on the basis of a model

[en] For the reprocessing of irradiated nuclear fuel, the PUREX process based on the principle of the solvent extraction using tributyl phosphate is the only industrially established process. Moreover recently, the research on the recycling of all actinides such as neptunium, americium and curium in addition to uranium and plutonium has been carried out. Hereafter, it is considered that the integrated reprocessing like this will be a powerful selection. If the process for adjusting the valence of actinides by only the excitation with light is developed, great merits are obtained, and the amount of waste discharged from fuel reprocessing plants is reduced remarkably. The attempt of utilizing photochemistry for fuel reprocessing has been done since 1970s, and the basic study on the photochemistry of actinides has been carried out in USA, Russia, Japan, India and others. However, it is difficult to evaluate the effect that the light-induced process exerts to the PUREX process. The low temperature distribution process of uranium and plutonium and the adjustment of the valence of neptunium to pentavalence are reported. (K.I.)

[en] The risks from routine discharges and accidental releases from nuclear chemical plant are considered. The role of 'tolerability' in deriving design guidance is discussed. Application of single plant criteria on the multiplant Sellafield site is then considered, and an evaluation of the overall risk is presented. (author)

[en] Technetium interferes in reductive partitioning of uranium and plutonium by catalyzing destruction of hydrazine, a stabilizer added to prevent oxidation of U(IV) by nitrous acid. In this communication, computer simulation results of technetium removal step by using a high acid scrub have been compared with the results from a published flowsheet. (author)

No abstract available

[en] The simple method of inhibition of nitration of extractant TBP by nitric acid in hydrocarbon solvent by the way of urea small additions (0.5-1g/l) intake in aqueous phase of extraction system is developed. It is shown that urea is produced the protecting effect on reaction of nitration of organic phase even in the presence of strong oxidizer - Cr(6)

[en] The nuclear power industry has been anchored to reactor systems based on uranium (natural and enriched) since its inception. Its long term sustainability was to be further enhanced by closing the fuel cycle with reprocessing and recycle of plutonium produced in the first generation reactors as MOX fuel in thermal or fast reactors. India believes that reprocessing and recycle of uranium and plutonium to be among the best of long term strategies for the safe management of spent fuel. We are interested in both uranium and thorium fuel cycles to meet our short as well as long term objectives. The paper describes the advantages of opting for a closed fuel cycle and the current status of our program on reprocessing and radioactive waste management and plutonium recycle options

No abstract available