Mutsuaki Shinagawa

Short-lived isotopes of lanthanum, cerium and praseodymium in neutron irradiated uranium☆

Abstract The separation of fission product La, Ce and Pr was performed within 90–180 sec by electromigration. As a supporting electrolyte, the solution of nitrilotriacetic acid ([NTA] = 3·7 × 10−3M, pH = 2·0, μ ∼ 0·05) was used. Rapid location of the zone on the paper strip reached after migration was obtained by color reaction of the carrier added to the irradiated uranyl nitrate solution. The γ-ray spectrum of each element was measured by a Ge(Li) detector connected with 512 channel pulse-height analyzer. In lanthanum fraction, at early times two prominent photopeaks at 395 keV ( T 1 2 = 40 ± 2 sec ) and 541 keV ( T 1 2 = 43 ± 3 sec ) were observed. From their decay rates, we presumed that they could be attributed to 144La ( T 1 2 = 41 sec ) whose γ-ray energies have not yet been reported. The two other photopeaks at 619 and 642 keV were assigned to the 14 min 143La and 92 min 142La. In Ce fraction, the photopeaks assigned to the 3 min 145Ce and to the 14 min 146Ce were observed, while no photopeaks could definetely be assigned to the 65 sec 147Ce. Some unreported γ-rays of 145Ce were found to be 233, 300, 429 and 915 keV. In Pr fraction, the 2·0 min 148Pr (γ-ray energy = 300 keV) and 12 min 147Pr (the photopeaks at 123 and 313 keV) were identified.

Rapid Separation of Fission-Product Rare Earths and Yttrium by Electromigration

The separation of fission-product La, Ce, Pr, Nd and Y was performed in 4 min by electro-migration. As complexing agent, nitrilotriacetic acid was used at two concentrations of the NTA ion selected so as to optimize mutual separation of the elements. Rapid location of the zone on the paper strip reached after migration was obtained by color reaction of the carrier added to the irradiated sample. The purity of the elements thus separated was checked by γ-ray spectrometry. At the higher concentration of NTA ([[NTA]=1.0×10−2M, pH=4.1) under which all of rare earths and Y migrate toward the anode, the elements were well separated from each other, although appreciable amounts of other F.P. were also found in each fraction. On the other hand, at the lower NTA concentration ([NTA]=4.0 × 10−3M, pH=2.0) where the F.P. all migrate toward the cathode, each zone contained the isotopes of the respective element almost exclusively, except for a few small photo-peaks attributable to other elements. In each fraction, the...

Gamma-Ray Energies and Half-Lives of Praseodymium-148 and -149

Rapid separation using NTA in paper electromigration was applied to the study of the γ-decay of 148Pr and 149Pr produced in the fission of 235U. The γ-ray spectrum was measured with a high-resolution Ge(Li) detector. The γ-transitions found to decay with half-lives shorter than 3 min were: 135, 162, 256, 300, 511, 614, 696, 868, 1,022 and 1,248 keV. Of these, the values of 300 keV, and of 135 and 162 keV were in fair agreement with those reported for 148Pr and 149Pr. The decay plot of the strong photopeak of 300 keV presented good linearity and the accurate half-life of 148Pr could be determined as 2.30±0.03 min, which is longer than the 1.98 min reported for 148Pr. Similar decay plots of both photopeaks at 135 and 162 keV gave a half-life of 2.9±0.1 min for 149Pr, which again is longer than the reported value of 2.3 min. Other low intensity photopeaks at 256, 696, 868 and 1,022 keV decaying with half-lives of 2.1∼2.4 min can possibly be attributed to 148Pr. The γ-transitions of 110, 578 and 742 keV repor...

Studies on Ionic States of Ruthenium by High Voltage Electrophoresis

As a method of rapid separation, high voltage electrophoresis (H.V.E.) was applied to analyze various ionic species of Ru (III) and Ru (IV) present in solutions. Change of the ionic forms in solution after preparation, and as well as their ultimate equilibrium state, were investigated in chloride media. In a similar manner, the effect of complexing agents, i.e. lactic acid, oxalic acid and nitrilo-triacetic acid, on the ionic forms of Ru(III) and Ru(IV) were surveyed. The results obtained were as follows. 1. Various ionic species of ruthenium coexisting in a dilute hydrochloric acid solution separated into four or five zones of migration in the case of Ru (III) and six or seven zones in the case of Ru (IV), after periods depending on their mobility. 2. Using an equilibrated sample, it was found that the ionic species practically did not change during a separation time of 5 to 18 min. Consequently, one can follow the kinetic changes of the ionic species if the reaction rate is not too high for neglecting r...

Polarographic studies on the catalytic wave of hydrogen with cobalt(II) sulphide

SummaryContinuing the studies of catalytic hydrogen evolution on mercury cathodes, results are reported about the influence of cobalt(II) sulphide on the polarographic hydrogen wave in ammonia ammonium chloride buffer. The influence of the concentration of thioacetamide and of the kind of supporting electrolyte on polarograms and instantaneous current-time curves is discussed. Furthermore, the gas evolving from a mercury pool cathode by controlled potential electrolysis was detected and identified. A mechanism of the catalytic action of cobalt(II) sulphide is proposed.ZusammenfassungAls Fortsetzung von Arbeiten über die katalytische Wasserstoffabscheidung an Quecksilberkathoden wurde eine systematische Untersuchung über den Einfluß von Kobalt(II)-sulfid auf die polarographische Wasserstoffstufe in Ammoniak-Ammoniumchlorid-Puffer angestellt. Der Einfluß der Konzentration des Fällungsmittels und der Zusammensetzung des Leitelektrolyten auf das Polarogramm und auf die Gestalt von Strom-Zeit-Kurven am Einzeltropfen wird ausführlich diskutiert. Das bei der potentiostatischen Elektrolyse an einer Quecksilberpool-Kathode entwickelte Gas wurde ebenfalls untersucht. Ein Mechanismus für die katalytische Wirkung des Kobalt(II)-sulfids wird vorgeschlagen.

Selective Gaseous Electro-Deposition of Lead-212 and Tellurium-208 from RdTh Source

Fractional electro-deposition of 212Pb and 208T1 from RdTh source using a capsule equipped with three electrodes was carried out under normal pressure. The experiment was conducted with variations brought to the applied voltage, the interval between the electrodes, time allowed for deposition and grid conditions. The active deposit thus obtained was examined by radiochemical and autoradiographical methods. Measurements of the active deposits on the electrodes showed that 212Pb had deposited on the grid net, and 208T1 on the target. The mechanism of the electro-deposition process under electric field with and without a grid is discussed on the basis of the decay pattern shown by each nuclide.

Behaviors of Impurities in Liquid Sodium, (II): Effect of Oxygen on Behavior of Hydrogen in Liquid Sodium

The behavior of hydrogen in liquid sodium containing relatively large amounts of oxygen were investigated with the aid of the hydrogen sensor of niobium membrane. The partial pressure of the hydrogen in liquid sodium at hot zone of a cold-trapped natural circulation sodium loop was measured as functions of temperatures of the cold trap and the hot zone of the loop. It was observed that at constant cold trap temperature the partial pressure of hydrogen in sodium increases with increasing the hot zone temperature. This study also showed that, keeping the temperature of hot zone constant, a logarithmic plot of hydrogen concentration calculated from the equilibrium hydrogen partial pressure vs. the reciprocal temperature of cold trap yields a straight line whose slope is nearly equal to that on the solubility of sodium hydroxide in sodium. Finally, it was observed that the permeation of hydrogen in sodium through a niobium membrane is a process controlled by diffusion. But the permeability for hydrogen in nio...

Separation Factor of Hydrogen and Deuterium by Suspension Electrolysis Using Mercury Cathode

The electrolytic separation factor between hydrogen and deuterium was examined using mercury or else platinum cathode immersed in IF NH4Cl in 10v/oD2O water containing cobalt sulfide powder in suspension. Several other kinds of powdered materials in suspension were also studied. In the case of mercury pool electrode, the materials added in suspension were effective in enhancing the hydrogen/deuterium separation factor, but powder suspension was ineffective on platinum plate electrode. The powdered material added in suspension served as catalyst on the hydrogen evolution reaction at the mercury cathode. The influence of the applied potential on the separation factor was studied over the temperature range of 15°~80°C. The results provided an indication of the rate-determining steps governing the electrolytic hydrogen evolution. The experimental values obtained for the separation factor and activation energy gave an insight into the mechanism of the rate-determining step of the hydrogen evolution at the work...

Effect of the addition of boron compounds on hydrazine formation in the radiolysis of an aqueous solution of ammonia

The effect of boron compound additives on hydrazine formation in the radiolysis of an aqueous solution of ammonia has been studied. Suitable boron compounds such as NH4BF4 and C2H5NH2BF3 were used as source of 10B(n, α)7 Li reaction. Ammonium hydroxide containing an additive was irradiated with thermal neutrons in the reactor KUR. When NH4BF4 was added to 15 M ammonium hydroxide, the yield of hydrazine depended on the boron concentration but did not depend on the irradiation time. On the other hand, hydrazine formed in the presence of C2H5NH2BF3 had a maximum value at about 5xl021eV/ml absorption dose. The characteristics of the added boron compounds are discussed with comparisons made between radiolysis incited by in-pile and 60Co γ irradiation. The effects of the additives are explained in terms of the hot atom effect of 10B(n, α)7Li reaction and the protecting effect of the resulting Lewis type acid, which inhibits the decomposition of hydrazine by scavenging the ·H and ·NH2 radicals.

The Construction of Charge-Spectrometer

The charge-spectrometer was constructed for the observation of the ionic fragments and the charge distribution following nuclear transformation. The optimum condition to collect and accelerate the ions in the source volume was confirmed for the 85 Kr of β- ·decay.Then, the correction factors for charge 1, 2, ……were determined and it was known that the correction factor depended pro portionally on the charge of ion.