Journal of Nuclear Science and Technology

Contribution of Heavier Nucleus on Neutron Slowing Down in Hydrogenous Mixture, (I)

Ryokichi TANAKA, Hiroji MOCHIZUKI, Tuneaki HAMAGUCHI, Kotaro NAGATO

1965 Volume 2 Issue 3 Pages 83-90
Published: 1965
Released on J-STAGE: February 28, 2008

DOIhttps://doi.org/10.3327/jnst.2.83

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The problem of neutron slowing down in hydrogenous mixtures was studied from an analytical approach. The coupled slowing down equations derived from P1-diffusion, using the G.G. or Fermi approximations, were solved consistently, and detailed expressions for special cases are discussed. It is shown that, in a system comprising two kinds of nuclei, the neutron energy spectrum has a transient term near a source, representing an interference effect between the neutron moderation by the two different kinds of nuclei. The consequence of the G.G. approximation is limited mainly to the transient region so long as absorption and leakage are negligible. When the mass of the non-hydrogenous nucleus becomes infinitely large, our general expression for the neutron energy spectrum derived from the G.G. approximation coincides with the result from the simple S.G. method.

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Distortion of Neutron Collision Density due to Resonance Scattering and Absorption

Hideo KUROI, Hiroshi MITANI

1965 Volume 2 Issue 3 Pages 91-98
Published: 1965
Released on J-STAGE: February 28, 2008

DOIhttps://doi.org/10.3327/jnst.2.91

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An analytical method for obtaining the collision density and the resonance integral in a homogeneous mixture of moderator and absorber is presented. The method incorporates ortho-normal expansion without any approximation such as narrow or wide resonance.
A new ortho-normal set of functions of which the weight function is of shifted Breit-Wigner type is introduced for this purpose.
Sample calculations are carried out for a mixture of ⁵⁹Co and heavy water, which is a typical case far removed from the two approximations mentioned.
Comparison of the results with numerically obtained exact solutions shows that the first four terms of the expanded series are sufficient to express the collision densities in this case.

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The Effect of Cylindrical Holes in a Moderator on the Passage of Virgin Neutrons from a Point Source

Hirokazu MURASE, Tamotsu SEKIYA, Tokuo SUITA

1965 Volume 2 Issue 3 Pages 99-103
Published: 1965
Released on J-STAGE: February 28, 2008

DOIhttps://doi.org/10.3327/jnst.2.99

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The mean free path and the mean square free path of 14 MeV neutrons, generated isotropically from a d-t point source located at the center of the moderator region of a square lattice composed of parallel circular cylindrical holes in water, are calculated for various void ratios. Very interesting inequalities between the axial and transversal components of the mean free path and the mean square free path are found, which contradict with the results of Behrens for homogeneous neutron sources. We may conclude that the effects on the free path lengths of the position of the point source located in an anisotropic and heterogeneous medium cannot be neglected.

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Decontamination of Cationic Radioactive Isotopes by Cationic Surfactants

Yoshiki WADACHI, Kazuo TAKADA, Yoshito YAMAOKA, Syun NOGUCHI

1965 Volume 2 Issue 3 Pages 104-107
Published: 1965
Released on J-STAGE: February 28, 2008

DOIhttps://doi.org/10.3327/jnst.2.104

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A study was made of the decontaminating mechanism of the cationic radioactive isotopes ⁶⁰CoCl₂ and ⁴⁵CaCl₂ by the cationic surfactants dodecyl benzyl dimethyl ammonium chloride and cetyl pyridinium bromide, by means of washing and paper chromatographic experiments. A reference experiment was also carried out with sodium dodecyl sulfate, to compare the effect of the above cationic surfactants with anionic ones. These experiments indicated that micelle formation was indispensable for the anionic surfactant, while this was not necessary for the cationic surfactant, since the monomer contributed to the decontaminating process. This means that the ionic process assumes a very important role in the decontamination of cationic radioactive isotopes by cationic surfactants in the absence of fatty soils.

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Separation of ^{141, 144}Ce, ⁹¹Y and ⁹⁵Zr-⁹⁵Nb from Fission Products by Tri-n-Butylphosphate

Tomitaro ISHIMORI, Yoshii KOBAYASHI

1965 Volume 2 Issue 3 Pages 108-111
Published: 1965
Released on J-STAGE: February 28, 2008

DOIhttps://doi.org/10.3327/jnst.2.108

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Separation of fission products was carried out by solvent extraction using tri-n-butyl phosphate (TBP). ^{144, 144}Ce, ⁹¹Y and ⁹⁵Zr and ⁹⁵Nb were extracted with TBP from a freshly prepared nitric acid-potassium bromate solution. These nuclides in TBP were successively back-extracted with various aqueous solutions: ^{141, 144}Ce with hydrogen peroxide and nitric acid solution, ⁹¹Y with hydrochloric acid solution, and ⁹⁵Zr-⁹⁵Nb with oxalic acid solution. The other nuclides were not extracted by the TBP and remained in the nitric acid and potassium bromate solutions.

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Separation of Promethium and Americium by Reversed Phase Chromatography

Kenju WATANABE

1965 Volume 2 Issue 3 Pages 112-114
Published: 1965
Released on J-STAGE: February 28, 2008

DOIhttps://doi.org/10.3327/jnst.2.112

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Errata Vol.2, No.1 (January, '65)

1965 Volume 2 Issue 3 Pages 114
Published: 1965
Released on J-STAGE: April 21, 2008

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