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Volume 11, Issue 12
Displaying 1-9 of 9 articles from this issue
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Tsunekazu AKIYOSHI, Akira KATASE, Yoshihisa WAKUTA, Masateru SONODA1974 Volume 11 Issue 12 Pages 523-534
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSEnergy spectra of neutrons scattered inelastically from natural samples of Ta, W, Au, Hg, T1, Pb and Bi have been studied at an incident energy of 14 MeV, using time-of-flight technique. Angular distributions were also measured for Ta and Bi. The energy spectra from 2MeV to 4 MeV were found to be qualitatively consistent with the prediction from statistical theory taking account of effects of nuclear pairing and shell structure. The Fermi gas level density parameter and the nuclear temperature were obtained by considering the contribution of the (n, 2n) reaction. The variation of level density parameter plotted against mass number was found to agree with the trend predicted theoretically by Newton. Angular distributions proved to be symmetric about 90° and the spin cut-off parameter was estimated to be about 5.8 for Ta and 4.3 for Bi. Cross sections for the (n, n') and (n, 2n) reactions were obtained.View full abstractDownload PDF (944K) -
A.I.M. RITCHIE, S.P. MOO1974 Volume 11 Issue 12 Pages 535-544
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe buckling concept is used in conjunction with diffusion asymptotic theory and examined with particular reference to pulsed systems. It is shown that the definition of buckling depends on the problem posed. The following three problems are considered :
(1) Comparison of a one mode diffusion theory calculation with experimental spatial distributions, with particular reference to pulsed fast systems
(2) Comparison of measured and calculated extrapolation distances in pulsed thermal systems
(3) Extrapolation distance appropriate to decay constant estimations in thermal systems.View full abstractDownload PDF (772K) -
R. SMYTH1974 Volume 11 Issue 12 Pages 545-553
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSAn investigation was carried out with the object of determining the physical effects of separation and the associated reattachment and redevelopment, upon the heat transfer charac-teristics of turbulent flow in pipes and to compare the results of these flow conditions with the fully developed one-dimensional condition and with a recently developed numerical technique for the solution of recirculating flows.
Separation of the flow was induced in a 4 ft length of 2 in. internal diameter nicrome tube of wall thickness 0.001 in. by means of a sudden enlargement of diameter at the entry of the tube. The tube was electrically heated by the passage of a current along its length. The first 25 in. of the tube was metered by thermocouples which gave the wall temperatures and from these the local heat transfer rates and Reynolds numbers up to 5 x 104 using air as the working fluid.View full abstractDownload PDF (646K) -
Mikio MORIOKA1974 Volume 11 Issue 12 Pages 554-560
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe volume oscillation of bubbles is a fundamental problem associated with the behavior of coolant in nuclear reactors and with reactor safety. Many studies have been reported on the oscillation frequency of a single bubble. Based on theory governing the behavior of single bubble, an accurate theory is derived on the natural frequencies of two pulsating spherical bubbles placed in an infinite liquid. The problem is reduced to calculation of the effect of a bubble on the inertial constant of the other bubble. Bispherical coordinates are introduced to calculate the velocity potential. The effects of liquid compressibilty and viscosity on the natural frequency are shown to be negligible. The most prominent result is that two kinds of frequencies are found to exist when two bubbles oscillate in phase and 180° out of phase. Examination further reveal that the analysis presented here includes Shima's solution as a special case. Numerical calculations substantiate the prediction that the resonant frequency of many bubbles is smaller than that of a single bubble.View full abstractDownload PDF (456K) -
Keisuke KOBAYASHI1974 Volume 11 Issue 12 Pages 561-570
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIt is shown that the monoenergetic diffusion equation in multi-region r-z geometry can be solved by the finite Fourier transformation method which has successfully been applied to x-y geometry. In this method, a system of linear algebraic equations is derived for Fourier co-efficients of fluxes and currents at the material boundaries between regions of constant cross sections, and all the boundary values are determined by solving this equation.
Numerical examples are presented for a problem featuring a fixed source and multiple regions, and the results are compared with those obtained from the current difference method. It is shown that the present method yields a better result with relatively few terms of expansion.View full abstractDownload PDF (616K) -
Eiko AKATSU, Toshi TOMIZAWA, Yasuyuki ARATONO1974 Volume 11 Issue 12 Pages 571-574
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSMost 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 2.7yr, 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 pre-sent work describes a method of separating 125Sb from fission products with use made of silica gel-itric 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±0.19)×10-1 mCi/gU at June 1972.View full abstractDownload PDF (338K) -
Possibilities of Using Organic Substances as MonitorToshiyuki NAKAJIMA, Shigueo WATANABE1974 Volume 11 Issue 12 Pages 575-582
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA new method is proposed for estimating the amount of exposure to γ-rays sustained by victims involved in a radiation accident. The concept is to use as measure of exposure the quantity of free radicals generated in organic materials by irradiation, and to determine this quantity through its relation to the electron spin resonance shown by substance containing such radicals. Applying this method, a minimum exposure of about 100 R could be estimated with measurements at room temperature. The monitor substances taken up for the present series of experiments included nails and hair taken from exposed persons, plastic button, polyethylene powder, lucite, paper and wool. The experiments were aimed at determining the sensitivity, the fading with lapse of storage time after irradiation and the effects of differences in condi-tions of storage such as temperature, illumination, and washing before measurement. The method thus developed should prove useful for estimating the extent of exposure, to serve in deciding the medical treatment to be applied.View full abstractDownload PDF (584K) -
Toshikazu TAKEDA, Seiichi TAKEDA1974 Volume 11 Issue 12 Pages 583-587
Published: December 25, 1974
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (279K) -
1974 Volume 11 Issue 12 Pages e1
Published: 1974
Released on J-STAGE: January 08, 2009
JOURNAL FREE ACCESSDownload PDF (28K)
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