巻号一覧
21 巻, 11 号
選択された号の論文の11件中1～11を表示しています
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Makio OHKUBO, Yuuki KAWARASAKI1984 年 21 巻 11 号 p. 805-813
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーNeutron transmission, scattering and capture experiments on the separated isotope 183W were carried out in the resonance region, using a time-of-flight spectrometer of the Japan Atomic Energy Research Institute linear accelerator. A 6Li-glass and a 7Li-glass detectors were used in pair-wise to determine the spins by detecting scattered neutrons and capture γ-rays. Resonance parameters E and 2gΓn were deduced up to 1.1 keV by analyzing the transmission data. Average level spacing <D> and s-wave strength function S0 were derived to be <D>=13.3±1 eV, S0= (1.24±0.22)×10-4 below 1.1 keV. Spins of 41 resonances were determined up to 900 eV from the capture and scattering experiments. The result on spin values supports the (2J+1) law on level density. The dependence of Γγ on spin values is inferred. Frequent appearence of spacing of 173 eV between two arbitrary levels is discussed.抄録全体を表示PDF形式でダウンロード (546K) -
Yoshiaki KIYANAGI1984 年 21 巻 11 号 p. 814-823
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーNumerical and experimental studies of the wing geometry moderator are performed in order to examine (a) the effects of the target position and the moderator thickness on the beam intensity and on the pulse shapes emitted from a polyethylene thermal moderator, and (b) the optimum thickness of the moderator.
The beam intensity emitted from the moderator is expressed by an integration of t12 product of the source neutron distribution and the beam intensity produced by a unit intensity point source in the moderator. By applying this expression mechanism is analyzed for the optimum target position and the saturation phenomena of the intensity and the pulse width emitted from the moderator. The optimum target position is at about 2 cm from the neutron emission surface for moderators thicker than 4 cm and at about half of the moderator thickness for thinner ones. The intensity and the pulse shapes emitted from the moderator vary little if the target distance is varied around the optimum one and become close to the saturated ones at about 8 cm thickness. It is indicated by the analysis of figures of merit that a moderator of 46 cm thickness is optimum.抄録全体を表示PDF形式でダウンロード (619K) -
Rainer MOORMANN1984 年 21 巻 11 号 p. 824-835
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーMassive ingress of air into the core of a high-temperature gas cooled reactor is among the accidents with a low occurrence frequency, but there are still gaps in understanding with respect to its consequences. In the present paper, massive air ingress combined with a delayed start of the afterheat removal system is investigated and compared to air ingress accidents with normal operation of the afterheat removal procedure. A computer programme REACT/THERMIX used for these accident analyses is described. For a high-temperature gas cooled reactor with a pebble bed core, it is shown that massive air ingress has no real safety endangering consequences even if the operation of the afterheat removal system is delayed by 6 h.抄録全体を表示PDF形式でダウンロード (985K) -
Yasuaki SHIINA1984 年 21 巻 11 号 p. 836-843
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーFlow around a circular, square and trapezoid-type turbulence promoter was studied putting it in a center of channels or on a wall for low Reynolds number. Frequencies and power spectrum intensities of shedding vortices behind a promoter were measured.
Results show that vortices behind the trapezoid cylinder were the strongest and the widest. Flow characteristics behind the trapezoid cylinder were similar to that behind the circular cylinder. Vortices behind the square cylinder were the weakest and the narrowest. Adequate shape of turbulence promoter for augmentation of heat transfer was discussed.抄録全体を表示PDF形式でダウンロード (2004K) -
Hitoshi SAKAI, Toshihide TSUJI, Keiji NAITO1984 年 21 巻 11 号 p. 844-852
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーThe oxidation of iron was investigated by Rutherford backscattering spectroscopy at 573 K under the oxygen partial pressure from 10-1 to 105 Pa for 324 h. In the first stage of oxidation, thickness of the oxide film reached the maximum around 1 Pa. In the second stage the oxidation obeyed the parabolic rate law. From 10-1 to 10-0.5 Pa the parabolic rate constant increased with increasing oxygen partial pressure due to the growth of magnetite, whereas from 1 to 100.5 Pa hematite covered magnetite but the parabolic rate constants were kept still high values possibly due to the presence of grain boundaries. Between 10 and 104.3 Pa the protective hematite coverage over magnetite kept the parabolic rate constants low regardless of oxygen partial pressure. At 105 Pa a sharp increase of the parabolic rate constant was observed due to the simultaneous growth of hematite and magnetite. The oxygen concentration in water for the inhibition of the corrosion may correspond to the oxygen partial pressure for the formation of protective film in gas phase around 573 K.抄録全体を表示PDF形式でダウンロード (3143K) -
Toshihiko YAMANISHI, Masahiro KINOSHITA1984 年 21 巻 11 号 p. 853-861
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーCharacteristics of a cryogenic distillation column having a small inner diameter (2 cm) were studied by separating N2 and Ar for Dixon Ring, Coil Pack, Helix and Heli-Pak. The size of the packings was 1/6 of the inner diameter of the column. The overall HETP value represented no dependence on the vapor flow rate regardless of the packing species used. A tendency common in the four packing species was that the discrepancy between the calculated and experimentally observed Ar concentrations at the middle of the column was enhanced by the decrease in the vapor velocity. This result is ascribed to the pheno-menon that the effective vapor/liquid interface area of a portion near the large condenser differs from that near the wire holding the packings. Packings having small void fractions and densely-coiled structure like Coil Pack made this problem more serious. Dixon Ring has an exceptionally large void fraction, nevertheless it presents an adequately large vapor/liquid interface area. In fact, it presented the best set of results of the lower pressure drop, smaller HETP and more readiness in predicting column behavior by the stage model.抄録全体を表示PDF形式でダウンロード (2442K) -
Shingo MATSUOKA, Hirone NAKAMURA, Takaaki TAMURA, Takemi TAKANO, Yasuo ...1984 年 21 巻 11 号 p. 862-870
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーNeutron activation technique was used to measure the amounts of I, Ag and Na elements in zeolite samples. The samples were nonradioactive before the activation analysis ; this facilitated various operations to investigate the chemical form of the sorbed iodine. It was found that the Ag+ ions positioned in three types of sites react differently with iodine as follows :
AgX•I2n, a physical adsorption product, released iodine immediately upon contact with water. (AgI)+ having a strong chemical bond did not release iodine either by heating or by submerging. (Ag …I)+ has a bond dissociation energy of several kcal•mol-1. When the sample was placed under water, part of the (Ag …I)+ ions released iodine very slowly and the remainder changed to thermally stable (AgI)+ ions. Ion-exchange reaction with aqueous sodium nitrate solution converted all of the (Ag …I)+ ions into stable AgI product. The Ag (3)+ ions reside in the inaccessible site for I atoms. The ratio of the populations was determined as :Ag(1)+ : Ag (2)+ : Ag (3)+= 0.33 : 0.51 : 0.16.抄録全体を表示PDF形式でダウンロード (687K) -
Takao TSURUTA, Norimichi JUTO1984 年 21 巻 11 号 p. 871-876
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーAs a highly sensitive, simple and non-radioactive neutron dosimeter, CR-39 plastic plates doped with a boron compound : ortho-carborane were prepared. After thermal neutron irradiation, the plates were etched in an aqueous solution of 30%KOH, at 60°C for 2 to 16 h. The etch-pits generated by 10B(n, α)7Li reactions were then counted using an optical micro-scope or an automatic track counting system. The density of the etch-pits on an irradiated plate increases with the etching time. When the etching time is kept constant, the etch-pit density is proportional to the irradiated thermal neutron fluence. The proportional constant is termed "sensitivity", which is 4.2×10-4 for a plate containing ortho-carborane at a con-centration of 0.5% by weight and for etching time of 16 h. By considering background counts, a thermal neutron dose of 0.025 mSv can be measured with this plate. The plates are insensitive to visible-, UV-, X-, β- and γ-rays and are easy to handle because the detector and converter are incorporated. There is no possibility of underestimating the dose equivalent due to fading. Furthermore, the isotopes of boron are not radioactive and thus are radio-logically safe.抄録全体を表示PDF形式でダウンロード (2639K) -
Tsutomu SAKURAI, Yoshihide KOMAKI, Akira TAKAHASHI, Mishiroku IZUMO1984 年 21 巻 11 号 p. 877-879
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーPDF形式でダウンロード (256K) -
Yoshiaki FUJITA, Katsuhei KOBAYASHI, Itsuro KIMURA, Saim SELVI1984 年 21 巻 11 号 p. 879-881
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーPDF形式でダウンロード (210K) -
Masahiro OSAKABE, Yasuo KOIZUMI, Kanji TASAKA1984 年 21 巻 11 号 p. 882-884
発行日: 1984/11/25
公開日: 2008/04/18
ジャーナル フリーPDF形式でダウンロード (184K)
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