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Volume 7, Issue 2
Displaying 1-8 of 8 articles from this issue
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Shoji NOMOTO, Takehiko YASUNO, Hisashi NAKAMURA1970 Volume 7 Issue 2 Pages 61-66
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMeasurements using nuclear emulsions have been made on the neutron spectra and on the fine structure of neutron fluxes in the cell of the I.4 core of the fast critical assembly at the Japan Atomic Energy Research Institute. The 1-4 core is a graphite-diluted fast core with 3:1 volume ratio of 20% enriched metallic uranium and graphite. The nuclear emulsions were irradiated in two typical patterns of arrangement of the cell (systems with graphite plates (a) bunched and (b) distributed among fuel plates).
For the distributed graphite plate system a marked discrepancy was found between the direct measurements and calculations based on the Monte Carlo method. This is attributed to anisotropy in the incident neutron flux due to the parallel plate arrangement of the simulated materials. It is concluded that Reines' formula requires correction to amount for such anisotropy, even when the emulsions are irradiated at the core center. A simple method for treating this anisotropy- is proposed for use in fine structure analysis. The method utilizes, in part, the calculated results.View full abstractDownload PDF (487K) -
Sunao SUGIHARA, Shosuke IMOTO1970 Volume 7 Issue 2 Pages 67-71
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe behavior in hydrolysis of uranium monocarbonitrides (UC1-xNx) of various compositions has been studied and compared with the hydrolysis of UN and UC. The products of the hydrolysis were found to be H2, CH4, C2H6, C3H8, NH3, CH3NH2, C2H5NH2 and C3H7NH2, and did not vary qualitatively with the composition (C/N), while quantitatively their relative amounts, and also the temperature of formation were found to be markedly affected by the composition. The more carbon-rich compounds tended to be easily hydrolyzed below 100°C, as in the case of UC, while the amenity to hydrolysis was found significantly weaker with the nitrogen-rich compounds, as with UN. The hydrolysis of carbonitrides is characterized by the formation of amines, which were found particularly abundant in the case of UC0.53N0.47 (C:N=1:1).
To elucidate the mechanism of the reaction under study, a mechanically mixed specimen of UN and UC was hydrolyzed. No amines were observed to be generated in this case. This finding was considered suggestive of two plausible mechanisms, namely, mutual interaction between free radicals located within short distances of each other, and the hydrogenation of skeletons such as C-C-N.View full abstractDownload PDF (347K) -
Takao HAYASH, Mitsuo KUDOH1970 Volume 7 Issue 2 Pages 72-81
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA method of temperature control in capsule irradiation, vacuum control method, was presented in the previous paper(1) in which both theoretical analysis and experimental results were discussed on the key factors of the method and on its applications. The present paper deals with the characteristics of the transient performance of this method. The theoretical analysis and experimental results are found to be in very good agreement, based on which the mechanism of the automatic temperature control of this system, is explained, and the key factors composing this system, discussed in the previous paper, are substantiated.View full abstractDownload PDF (644K) -
Itaru MICHIYOSHI, Tsuyoshi NAKAJIMA1970 Volume 7 Issue 2 Pages 82-91
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThis paper deals with an analysis of flow characteristics and heat transfer of a Bingham plastic fluid in laminar flow through concentric annuli.
The friction factor obtained for a given Hedstrom number in fully established flow varies with the radius ratios of the annular space and of the bounds of the plug region.
The Nusselt numbers at the two wall surfaces in both fully developed and thermal entrance regions are calculated under the conditions of uniform internal heat generation and uniform but mutually differing heat fluxes at the two wall surfaces. Analytical results show that the Nusselt numbers become negative or infinite under certain thermal conditions at the walls.View full abstractDownload PDF (574K) -
Tetsuo HASHIMOTO, Tadaharu TAMAI, Rokuji MATSUSHITA, Yoshiyuki KISO1970 Volume 7 Issue 2 Pages 92-96
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe effect of carriers on the chemical behavior of 131I produced from the 130Te(n, r)131Te→β-131I processes was investigated with paper electrophoresis, autoradiography and r-ray spectrometry.
If no carrier was added, the chromatograms of the iodine species revealed significant deposits of an unexpected chemical species between the spots of the iodide and iodate species. The addition of either iodate or periodate as carrier converted the species into iodate in the former case, and into iodate and periodate in the latter.
Referring to the already known exchange reactions between different iodine species, hence was concluded that the species observed in the experiment without carrier was the iodite species (IO-2), as surmised by previous authors.View full abstractDownload PDF (317K) -
Masao MATSUI, Hiroshi SEKI, Takashi KARASAWA, Masashi IMAMURA1970 Volume 7 Issue 2 Pages 97-104
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSSystematic studies on the LET effect in the radiolysis of organic liquids have been initiated using various types of heavy ions accelerated by cyclotron. First, the effects of differences in irradiation conditions, in particular beam current, stirring speed and concentration of solutes have been examined. Aerated aqueous ferrous sulfate solutions (Fricke solutions) were subjected to irradiation by protons and He ions of various energies, to take advantage of the well-established reaction mechanism of the system. Experimental results obtained under various conditions were analyzed on the basis of the diffusion kinetics model. It was revealed that meticulous care must be taken to control the experimental conditions in studying radiolysis with heavy ions. The oxidation yields of ferrous ions were also determined as a function of linear energy transfer.View full abstractDownload PDF (592K) -
Tadaoki YAMASHITA, Kunio SAKAI, Saburo KITAMURA1970 Volume 7 Issue 2 Pages 105-110
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSCaSO4 : Pb, Mn has been found to be free from the serious disadvantage of rapid fading possessed by CaSO4 : Mn, the most sensitive thermoluminescence phosphor available so far. A study has been made on the effect of lead and manganese content on CaSO4, and it is concluded that lead in CaSO4 produces new traps for radiation energy, resulting in improvement of the properties of the phosphors for dosimetry. The optimum content of such activator additives was found to be 0.2 n14/7 of lead and 3 m% of manganese.
The improved phosphor thus obtained produces glow peaks at 160° and 190°C, and the energy yield of the thermoluminescence is about 4 %, which is twice that of CaSO4 : Mn. The more significant properties of this phosphor from the viewpoint of application to radiation dosimetry include:
(1) Linear responce from 50μR to 104R
(2) Minimum detectable dose of 50μR±25 % by experimental reader
(3) Fading rate of 5 % in a weekView full abstractDownload PDF (416K) -
Kensuke SHIRAISHI1970 Volume 7 Issue 2 Pages 111-112
Published: February 25, 1970
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (155K)
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