Journal of Nuclear Science and Technology
Online ISSN : 1881-1248
Print ISSN : 0022-3131
Volume 4, Issue 4
Displaying 1-9 of 9 articles from this issue
  • Shoichiro NAKAMURA, Toyohiko TSUCHIY, J. Tsunetaka WAJIMA WAJIMA
    1967 Volume 4 Issue 4 Pages 159-163
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    To present a simple method for calculating the worth of control rods in multiregion reactor cores, the well model approximation is applied to the finite difference diffusion code. The results of calculation are compared with experimental results obtained on the Ozenji Critical Facility, and also with calculations using transport equivalent constants. With its simplicity, the method proposed is accurate enough to suffice amply for most cases where only the reactivity is the end result sought, although the application of this method is limited to control rods inserted in the core region, and gives no information about the detailed neutron flux distribution around the control rod.
    Download PDF (341K)
  • Fission Gas Release from UO2-Graphite Mixture during Irradiation
    Seishi YAJIMA, Yuichiro KAMEMOTO, Muneo HAND, Shigeru YAMAGISHI, Takes ...
    1967 Volume 4 Issue 4 Pages 164-170
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    Fission gas release from a UO2-graphite mixture was studied during irradiation with the use of the Fission Gas Release Loop in the JRR-3 reactor. The release rates of fission krypton and xenon increased proportionally with neutron flux (6×1010-6×1012n/cm2•sec) and exponentially with temperature (400°-1, 000°C). A burst of fission gas was observed when the specimen was abruptly heated to a higher temperature. These results can be explained by a mechanism whereby fission gas is trapped in defects created in graphite by fission fragments and released through annealing of the defects.
    Download PDF (500K)
  • Tadashi KUBOTA, Shuichiro TAKAHASHI
    1967 Volume 4 Issue 4 Pages 171-176
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    Several rare earth metal oxide dispersions in UO2-Eu2O3, Dy2O3 and Sm2O3 were subjected to steep temperature gradient at near melting temperature of UO2 to investigate the compatibility of rare earth metal oxides with UO2.
    The principal results obtained are as follows :
    (1) Grains of massive form having a directional growth tendency were formed in the central region of the UO2 containing the dispersions of rare earth metal oxides. No signs of columnar grain growth were observed, such as have been reported in UO2 free of added elements.
    (2) The original shapes of all three rare earth metal oxide particles were lost in the massive grain region.
    (3) Various particular characteristics were observed in the microstructure of the different rare earth metal oxide-UO2 systems.
    Download PDF (2759K)
  • Yoshihiko KANEKO, Ryosuke KUROKAWA, Fujiyoshi AKINO, Kenji SUMITA
    1967 Volume 4 Issue 4 Pages 177-184
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    A series of pulsed neutron experiments was performed to investigate the chemical binding effect on the neutron slowing down time. Bursts of D-T neutrons of 1 μsec width were generated in a hexagonal prism with 240 cm high with 120 cm flanks, made of reactor grade graphite with a density of 1.54. The slowing down neutrons were detected by bare as well as energy-selective filter-covered BF3, counters, and analyzed with a 256 channel time analyzer. Slowing down times in graphite were deter-mined by interpreting the increment of the difference of events between the two counters to be due to the contribution made by the fraction of the slowing down neutrons at the time of measurement that was below the cut-off energy of the filter. The results of measurements showed good agreement with calculation based on the crystal model
    Download PDF (492K)
  • Yoshiaki MARUYAMA
    1967 Volume 4 Issue 4 Pages 185-189
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    High purity 18F was prepared by irradiating 1g of lithium hydroxide or otherwise 0.14g of enriched lithium carbonate containing 50% 6Li in the pneumatic tube of a TRIGA-II research reactor at a thermal neutron flux of 1.2×1012 n/cm2•sec.
    After cooling for 20min, the irradiated lithium hydroxide was dissolved in distilled water. The resulting 18F was separated from the irradiated target by passing the lithium hydroxide solution successively through ion exchange columns of H-, OH- and H-forms. Use was also made of the Co-form ion exchange column in place of the H-form for the elimination of impurities. In the case of 6Li enriched lithium carbonate, the irradiated lithium carbonate was dissolved in hydrochloric acid, and ion exchange columns of Ag-, OH- and H-forms were used for purifying the 16F. The product 18F was obtained in the form of water containing 18F. The chemical yield for the purification of 18F was about 80% and the final radioactive impurities were less than 1ppm.
    A neutron activation method for determining the isotopic abundance of 6Li was developed using the nuclear reactions 6Li(n, α)3H and 16O(t, n)18F. Aqueous solutions containing lithium were irradiated in pneumatic tube for 1hr. 18F was separated by steam distillation from the irradiated solutions and precipitated as magnesium fluoride. The chemical yield for the separation of 18F was about 80%. The sensitivity limit was estimated to be 4μg of natural lithium.
    Download PDF (346K)
  • Exchange Resin
    Kazuo WATARI, Kiyoko IMAI, Masami IZAWA
    1967 Volume 4 Issue 4 Pages 190-194
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    The adsorption and desorption of 137Cs on copper ferrocyanide-anion exchange resin, prepared in the manner previously reported in this Journal in a Short Note, are presented in detail.
    This resin can also be used for the concentration of the 137Cs found in sea water. The nuclide is adsorbed effectively on the resin from water, hydrochloric acid below 4M, and on nitric acid below 1M. After adsorpaion on the resin, 137Cs is eluted easily with either nitric acid (>6M), ammonium water, or silver nitrate solution.
    Adsorption on the resin is specific for 137Cs, and the action is due entirely to the ferrocyanide moiety of the resin.
    This method is more efficient than the co-precipitation method with copper ferrocyanide for the concentration of radiocesium from a large volume of sea water
    Download PDF (351K)
  • Seishi TAKED, Hiroshi NISHIHARA
    1967 Volume 4 Issue 4 Pages 195-204
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    An elementary method of wave form analysis for semiconductor detectors under certain working conditions is derived from a simple model of pulse formation. Agreement of the calculation with the corresponding experimental results is satisfactory.
    The experiments were carried out on an M-8311-A-50 detector (TOSHIBA, 2, 500Ωcm, p-type Si). The load resistance was in the range 100-50, 000Ω. The amplitude and the rise-time have been found to be in the ranges 1-6mV and 3-9ns, respectively. The energy spectrum of detector pulse for low load impedance extends up to ca. 50 Mc.
    Download PDF (1575K)
  • Masahiko UTSURO, Toshikazu SHIBATA
    1967 Volume 4 Issue 4 Pages 205-208
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    Download PDF (311K)
  • Yoshiki WADACHI, Shingo TASHIRO
    1967 Volume 4 Issue 4 Pages 208-209
    Published: April 25, 1967
    Released on J-STAGE: April 18, 2008
    JOURNAL FREE ACCESS
    Download PDF (103K)
feedback
Top