Journal of Nuclear Science and Technology
Online ISSN : 1881-1248
Print ISSN : 0022-3131
6 巻, 4 号
選択された号の論文の12件中1~12を表示しています
  • Mitsuru KOIKE, Enzo TACHIKAWA, Takao MATSUI
    1969 年 6 巻 4 号 p. 163-169
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    The γ-radiolysis of aqueous boric acid solutions of relatively high concentration has been studied. Boric acid significantly promotes hydrogen formation up to 10-7 molm/l but does not increase oxygen and hydrogen peroxide to any appreciable extent. Since boric acid reacts at a relatively slow rate with species formed by the primary process of water radiolysis, when an effective scavenger for e-aq - the precursor of H2 - such as NO-3 is present, boric acid has no effects upon the total yield of H2 in the range of concentrations studied. However, the yields of other products of the radiolysis - H2O2 and NO-2 -are significantly reduced at high concen-trations of boric acid when NO-3 is present.
    These results are explained by established reaction schemes for the radiolysis of aqueous solution. Based upon the behavior of NO-2 from nitrate solutions, it is suggested that -2 reacts with H3BO3 or H2BO3 radicals, the plausible reaction product from the reaction,
    H3BO3 + OH → H2O + H2BO3.
  • Joseph S. ROSEN
    1969 年 6 巻 4 号 p. 170-181
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    The calculus of variations is used to optimize the proton shield weight consistent with certain proton attenuation requirements, for voids which are bounded by general surfaces and shielded by some or all available materials suitable for proton shields. The thickness of the shielding materials and their order at each point are found in terms of a variable Lagrange multiplier, the relative stopping powers and densities of the eligible shielding materials and the geometry of the void surface at the point. Regions on the surface of the void are delineated wherein all the prescribed shielding materials can be used, while in other regions some of these materials must be dropped in a given order.
  • Yasutake OSAWA
    1969 年 6 巻 4 号 p. 182-193
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    A study was made of the oxidizing behavior at high temperature (800°C1, 800°C) in vacuum of UC, UN and U(C, N) samples containing added oxygen in excess amounts, through observa-tions of gas release, X-ray diffraction analysis, and microphotography.
    The oxidation in vacuum of UC and U(C, N) was found to proceed above 1, 200°C by stepwise reactions from one temperature interval to the next, the process differing however according to the chemical state of the oxygen present in the samples. In the temperature range below 1, 200°C, the UC and U(C, N) samples reacted violently with the free oxygen present in dissolved state, to form UO2. Between 1, 200° and 1, 400°C the UO2 thus produced reacted with the UC or U(C, N), forming solid solutions of U(C, O) and U(C, N, O) respectively: Above 1, 600°C, these solid solutions gradually decomposed back into UC and U(C, N), and U. In all stages of oxidation, large amounts of CO - and N2 in the case of U (C, N) - evolved from the samples as reaction products. In the case of UN, no reaction was observed below 1, 200°C, and only oxidized above that temperature to form UO2 and N2 by the action of the dissolved oxygen present.
    These results indicate that in the case of UC and U(C, N), the quantity of gases evolving from the oxidation is dictated by the total amount of oxygen contained in the samples, while that from UN is dependent on the amount of molecular oxygen alone.
  • Hiroshi MIZUTA, Takanobu KAMEI
    1969 年 6 巻 4 号 p. 194-202
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    The results of some quantitative studies on resonance interference are presented. The calcu-lations were performed on a FORTRAN IV program RICM2, which solves numerically the slow-ing down of neutrons over many resonance levels in a two region lattice, and gives reaction rates, average cross sections and effective resonance integrals of the nuclides concerned.
    Three combinations of resonant nuclides, 235U-238U, 239Pu-238U and 239Pu-240PU, were considered, in conjunction with three oxide fuel rod radii, 0.2, 0.5 and 2.0 cm, the moderator (light water) to fuel volume ratio being maintained constant at 2.0. An energy range below 150eV has been covered by the present calculations. The effects of resonance interference have been found to be appreciable in this energy range.
  • Kaoru UENO, Masakatsu SAEKI, Tomitaro ISHIMORI
    1969 年 6 巻 4 号 p. 203-206
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    A reverse-phase chromatographic isolation procedure for Nb from Mo and Tc is given. The separation is performed with TBP (tri-n-butyl phosphate) on celite column.
    Molybdenum oxide was irradiated with 20 MeV bremsstrahlung, which produces a mixture of 93mMo, 99Mo; 99mTc; 91mNb, 95Nb and 96Nb. The irradiation was applied to a 6 N HCI solution of the target. Separation was repeated twice, which resulted in isolation of the radioniobium with a decontamination factor of 104 both for Mo and for Tc.
    Decay analysis of the activity showed that radioniobium thus separated was composed of 91mNb, 95mNb, 95Nb and 96Nb. The γ-spectrum of 96Nb was obtained by subtraction of the spectrum taken 119 hr after the end of irradiation from that of 74 hr.
  • Fujio TACHIBANA, Akira OYAMA, Mamoru AKIYAMA, Shunsuke KONDO
    1969 年 6 巻 4 号 p. 207-214
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    The heat transfer characteristics of non-concentric annuli with various eccentricities and also of a seven-rod cluster were experimentally determined by means of mass transfer technique. A coating of naphthalene was applied to the surface of the test rod and changes in its thickness measured. The mass transfer coefficients have been represented in terms of Colburn's j-factor, with which both the average and local values were analyzed. The measured average heat trans-fer j-factors were found to be in part equal to those for smooth round ducts, but the circumfer-ential variations of the local factors for the eccentric annulus did not agree with the theoretical prediction proposed by Dwyer & Yu. The existence of secondary flow in the seven-rod cluster is also discussed.
  • Analysis of Doppler Limited Power Burst
    Hidemasa KATO, Munemaro IMAI
    1969 年 6 巻 4 号 p. 215-220
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
    The power excursion characteristics of a water-moderated UO2 fuel reactor were investigated by pulse operation tests on the Hitachi Training Reactor. A series of pulse operation tests were performed without mishap with reactivity insertions up to 1.20% Δk/k, corresponding to a reactor period of 15 msec. With a reactivity insertion of 1.20% Δk/k, the peak power and energy release to the time of peak power were found to be restricted by the Doppler effect to 118 MW and 4.1 MW•sec respectively. Comparison were made between experimental and calcu-lated values of peak power and energy for various published resonance integral temperature coefficients.
  • 1969 年 6 巻 4 号 p. 220a
    発行日: 1969年
    公開日: 2008/04/18
    ジャーナル フリー
  • 1969 年 6 巻 4 号 p. 220b
    発行日: 1969年
    公開日: 2008/04/18
    ジャーナル フリー
  • Toshio HONDA, Takeo KIKUCHI
    1969 年 6 巻 4 号 p. 221-222
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
  • Kazumi IWAMOTO
    1969 年 6 巻 4 号 p. 222-224
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
  • Ryosuke YOKOTA, Saburo NAKAJIMA, Kazuyoshi BINGO
    1969 年 6 巻 4 号 p. 224-226
    発行日: 1969/04/25
    公開日: 2008/04/18
    ジャーナル フリー
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