巻号一覧
後続誌
6 巻, 3 号
選択された号の論文の8件中1～8を表示しています
- |<
- <
- 1
- >
- >|
-
中村 勝一, 志水 秀文, 田中 浩史, 丹羽 健夫1964 年 6 巻 3 号 p. 129-134
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーCore-tank of UTR-B is separated in six sections. Each section has a length of 83.3mm in east-west direction, and holds a fuel element which has a length of 76.2mm in the same east-west direction.
It may be expected that the reactivity of this reactor would be changed, if each fuel element is shifted towards the center line of the core-tank or in the opposite direction.
We examined this possible reactivity change due to the slight shift of the fuel elements, and obtained the following results; if each fuel element is shifted toward the center line of the core-tank, the reactivity of the reactor increases and the critical mass decreases. If each fuel element is shifted outward in the opposite direction, the reactivity of the reactor decreases and the critical mass increases.
This effect is smallest in near the center line of the core-tank, and the farther the position is off the center line, the larger the effect becomes. But in near the side of the core-tank, this effect comes small again.
This may be affected by the thermal neutron flux distribution and the importance function. We have measured the thermal neutron flux distribution in the core-tank, and calculated the importance function.
The curve of the statistical weight vs. position of the core-tank had shown to have a same tendency of the experimental results.抄録全体を表示PDF形式でダウンロード (305K) -
山本 一雄1964 年 6 巻 3 号 p. 134-143
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーBy heating the mixture of UO2 and graphite in vacuum at 1, 600° to 2, 000°C, UC or UC2 without unreacted UO2 was obtained. Each of these carbides was milled in hexane, compacted into shapes in argon atmosphere and the sintered in vacuum (10-4mmHg) at 1, 800° to 2, 000°C. High purity and high density (95% th.D.) pellets were thus obtained. Examining these sinterd pellets by carbon analysis, metallographic observation and X-ray diffraction, the following facts were revealed.
(1) UC sintered pellet had a monophase structure with a grain size of 50100μ and the stoichiometric composition.
(2) UC2 sintered pellet was composed of UC2 phase with grain size of 50100μ and UC phase of about 10%.
(3) Sinterability of UC2 markedly decreased with increasing carbon content in the range of 8.6 to 8.9_??_. This change was attributed to the presence of free carbon.
(4) Maximum carbon content of UC2 phase at the temperature range of 1, 800° to 2, 500°C was determined as 8.6±0.1_??_, that is, the composition of this phase could be expressed as UC1.86±0.02.
(5) The kinetics of transformation of cubic UC2 to tetragonal one was regarded as a martensitic diffusionless one.抄録全体を表示PDF形式でダウンロード (2889K) -
西村 佳寿雄, 岩瀬 昭和, 高橋 敏猛, 柳沢 一二三, 福光 良雄, 松延 広幸, 前島 享1964 年 6 巻 3 号 p. 144-153
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーThe comparisons of nuclear characteristics were made between the circular cell (BR-2 type core unit cell), and the rectangular cell (ETR type core unit cell) in the Material Engineering Test Reactor. The uranium weight ratio of U-Al alloy for the meat of fuel plates is taken as a parameter. Design parameters such as critical mass, average flux of the loop per unit power, allowable maximum flux of the loop, mass coefficient and void coefficient were examined as criterions for the comparisons. In view of co-existence of beryllium and light water in the circular cell, the advantage of beryllium was studied. In the calculation, the thermal utilization of the circular cell was estimated as exactly as possible, solving the space dependent thermalization formula. The conclusions obtained by this study include,
(1) We can load the fuels in the rectangular cell more tightly than in the circular cell. But we can not find the essential difference in each case if we can adjust the weight ratio parameter easly.
(2) When we desire high allowable flux of the loop or high flux of the loop per unit power, we may adjust the uranium weight ratio in accordance with the requirement.
(3) If we fill up the gap of the tightly loaded circular cells with beryllium which has smaller absorption cross section than light water, and if we can adjust the uranium weight ratio easily according to the requirement, it might be said that the circular cell has some advantage because of the improved thermal utilization.
(4) We can take the negative void coefficient in the circular cell more easily than the rectangular one.抄録全体を表示PDF形式でダウンロード (529K) -
西島 寅次, 川田 俊行1964 年 6 巻 3 号 p. 154-158
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーThe behavior of sintered UO2 pellets (96.0% T. D.) at elevated temperature was preliminarily investigated and following results were obtained:
(1) Hardness was measured in the temperature range from -180° to 800°C: With increasing temperature hardness of UO2 decreased rapidly at the lower temperature range and slowly in the temperature range above 200°300°C. For comparison, hardness of several kinds of metal was measured under the same condition as UO2, among which tungsten showed similar temperature dependence of hardnass with UO2.
(2) Microscopic observation was done around the indentation caused by the diamond pyramid indenter of the Vickers hardness tester: It was found that the number of cracks in the specimen indented decreased gradually with increasing temperature and disappeared completely in the specimens indented above 500°C.
(3) Specimens were annealed in hydrogen atmosphere after indented at various temperatures: No change was observed in the specimens indented at relatively low temperatures. While in the speciments indented at temperatures above 400°C, abnormal grain growth was observed around the indentation after annealing at 1, 700°C.
Finally these experimental facts were discussed and it was concluded that they would be due to the plastic nature of UO2.抄録全体を表示PDF形式でダウンロード (990K) -
融解ビスマス-LiCl-KCl共融混合物系における銅の挙動山岸 滋, 亀本 雄一郎1964 年 6 巻 3 号 p. 158-164
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーThe chemical state and distribution coefficient of copper in the fused bismuth-fused LiCl-KCl system were investigated at 550°C in argon or air atmosphere with and without oxidant and reductant.
In argon atmosphere, a compound of monovalent copper was more stable than a compound of divalent copper in the fused LiCl-KCl. Then, the cupric chloride added to the fused LiCl-KCl was converted to a colorless compound of monovalent copper with lapse of time. On the other hand, a compound of divalent copper was stable in air atmosphere. The distribution coefficient of copper between fused bismuth and fused LiCl-KCl was 3 and 1×102 in argon and air atmosphere, respectively, at 550°C.
It was found that the distribution of copper between fused bismuth and fused LiCl-KCl was influenced in argon atmosphere by the presence of reductant or oxidant. Using a bismuth-magnesium alloy (0.2%Mg) in place of bismuth, little copper was extracted from the alloy into the fused LiCl-KCl and the distribution coefficient of copper was made 2×10-3. When excess bismuth chloride was added to the fused LiCl-KCl as an oxidant, copper was almost completely extracted from the fused bismuth into the fused LiCl-KCl and oxidized to a divalent compound. After the bismuth chloride added was used up for the oxidation of copper, the copper extracted in the fused salt was converted to the monovalent state and transfered back into the fused bismuth until an equilibrium was established.抄録全体を表示PDF形式でダウンロード (428K) -
1964 年 6 巻 3 号 p. 165-177
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーPDF形式でダウンロード (739K) -
1964 年 6 巻 3 号 p. 178-180
発行日: 1964/03/30
公開日: 2009/03/26
ジャーナル フリーPDF形式でダウンロード (212K) -
1964 年 6 巻 3 号 p. 186
発行日: 1964年
公開日: 2009/03/26
ジャーナル フリーPDF形式でダウンロード (76K)
- |<
- <
- 1
- >
- >|