Eiko Akatsu

Determination of traces of ruthenium by addition of cerium(IV) and atomic absorption spectrometry

Abstract The sensitivity of the determination of ruthenium by flame atomic absorption spectrometry is increased 60 times by adding 1 × 10 −2 M cerium(IV). Calibration is linear over the range of 0.05–5 μg ml −1 ruthenium. A method applicable to nitrosylruthenium complexes is described. The increased sensitivity results from formation of ruthenium tetroxide.

Radiochemical studies on the solvent extraction of several elements in Mn(No3)2.6H2O-and CaCl2.6 H2O-Tri-n-Butyl Phosphate systems

Abstract A solvent extraction study was carried out at 30° with organic phases of tri- n -butyl phosphate(TBP) in dodecane and inorganic phases of molten manganese nitrate hexahydrate (m.p. 25.8°). Distribution ratios of several rare earth and actinide elements and fission products were determined with TBP solutions of various concentration. The values obtained were higher than those in TBP-nitric acid system. Calcium chloride hexahydrate (m.p. 29.9°) was also used in a similar way.

Liquid-liquid extraction of several elements in the system of fused Ca(NO3)2. 4H2O and tri-n-butyl phosphate

Abstract The liquid-liquid extraction of several elements of actinides and fission products was radiochemically studied in the system of fused calcium nitrate tetrahydrate and tri- n -butyl phosphate in n -paraffin diluent at 45°C. The solvation number of several elements in the organic phase was graphically determined by the dilution method using the obtained distribution ratios. The solvates were similar to those in the aqueous nitrate and the anhydrous nitrates eutectic-tri- n -butyl phosphate systems.

SOLVENT EXTRACTION BEHAVIOR OF MACROAMOUNTS OF ELEMENTS IN 100% TBP-NITRIC OR HYDROCHLORIC ACID SYSTEMS

The acid dependence curves of 15 inorganic ions in macroamounts were surveyed for the system of 100% TBP-HC1 and HNO3, and compared with results obtained in tracer work previously reported. In most cases, theKd values measured in a system containing 0.1m/l salt are little different from those determined by radioactive tracers. The acid dependence behavior of ferric and zinc chloride were especially studied with varying metal ion concentrations. Additional experiments were carried out for ferric and zinc chloride in the system of 1 % (w/v) TBPO and 5 % (w/v) TOPO toluene-HCl. In these cases theKd values lowered with increasing chloride concentration.

Ion Exchange Behaviors of Inorganic Ions in Ion Exchange Resins of Diaion SKN-1 and SAN-1

The distribution ratios of 42 inorganic ions were radiochemically determined in a system of Diaion SKN-1 in H-form and 0–4M hydrochloric acid, and in another system of Diaion SAN-1 in Cl-form and 1–9M hydrochloric acid. The results are presented in an arrangement that follows the sequence of the periodic table. Several data were also obtained on Amberlite IRN-77 and −78 for comparison.

Separation of zirconium from fission products in silica gel—nitric acid systems

Abstract A method for the separation of zirconium from fission products based on the system 100–200 mesh silica gel—2.0 M nitric acid is described. Decontamination factors are over 500 for 95 Nb, 106 Ru, 124 Sb, 137 Cs, molybdate and uranium(VI), and the yield of zirconium is 98 %.

Radiochemical studies on the liquid-liquid extraction of several elements in fused manganese nitrate hexahydrate-tri-n-butyl phosphate in various diluents

Abstract The liquid-liquid extraction of several elements was radiochemically studied in several fused manganese nitrate hexahydrate (m.p. 25.8°)-tri- n -butyl phosphate diluent systems at 30°; the diluents were xylene, chloroform and 1-hexanol. The distribution ratios of several elements were higher than those in nitric acid systems with each diluent. The dependence or the distribution ratios on various diluents was almost similar to that in nitric acid systems.

Flow Rate and Decontamination Factor of 137Cs and 131I through Mixed Resin Bed

Aqueous solutions of 131I and of 137Cs were passed through an ion exchange resin column. The resin bed consisted of a 2:1 mixture of cation and anion exchange resins, Diaion SKN-1 in H form and Diaion SAN-1 in OH form. The decontamination factors for these radioisotopes were determined at various flow rates, i.e., space velocities of 25–200. The decontamination factor decreased with increasing flow rate for both radioisotopes. The Kd value of l37Cs between Diaion SKN-1 and water was about half that of 131I between Diaion SAN-1 and water, but D.F. of 137Cs was higher. Distribution of 137Cs in the resin column was also studied. Most of radioactivity was found at the top of the resin column.

Separation of Antimony-125 in Fission Products

Most of the known radioactive nuclides of antimony produced by neutron irradiation of uranium have fission yields below 1% and have half-lives below 60 days. An exception is 125Sb with a half-life of 2.7 yr, which raise its relative importance among the fission products with lapse of time after irradiation, and after 1 yr of cooling, its radioactivity is no longer negligible. This circumstance has led to its being separated from such sources as fall-out. No studies have so far been reported on using the nitrate system for this separation, though it is utilized in the reprocessing of spent fuel and in the dissolution of uranium samples. The present work describes a method of separating 125Sb from fission products with use made of silica gel—nitric acid system, and an example of its application to the separation of 125Sb from the spent fuel of JPDR-1. The fuel was irradiated from Oct. 1963 to Sep. 1969. The amount of 125Sb measured after separation was (1.7± O.19)×10−1Ci/gU at June 1972.

A Method of Preparing of Cobalt-58

Carrier-free 58Co produced through (n, p) reaction, is usually prepared by ion exchange, but in this study the graded multistage solvent extraction method was successfully applied to the separation of 58Co from nickel. Nickel sponge of high purity was irradiated for 151ir in the JRR-1 reactor at Tokai. A dilute hydrochloric acid solution of about 0.2 mC of 58Co was obtained from l g of nickel sponge by the above mentioned method. The radiochemical purity was determined by means of γ-spectrometry and decay curve measurement.