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研究報告14-1
解説
深田 智、西川 正史
九州大学工学部応用原子核工学科
〒812 福岡市東区箱崎6-10-1
Satoshi FUKUDA, Masabumi NISHIKAWA
Department of Nuclear Engineering, Faculty of Engineering, Kyushu University
Hakozaki, Higashi-ku, Fukuoka 812
(Received August 1, 1994); accepted November 28, 1994)
ABSTRACT
Several methods for tritium recovery from liquid lithium, Li-Pb eutectic alloy, aqueous salt solution or fluoride salt (Flibe) of the breeding materials of a fusion reactor were comparatively investigated based on engineering designs. The methods of a permeation window, an yttrium particle bed and molten salt extraction were promising for liquid lithium. The methods of a permeation window, counter-current extraction in a packed bed and cold trapping in a Na or NaK loop were hopeful for tritium recovery from Li17 Pb83 eutectic. The methods of helium gas purging and vacuum extraction were successfully applied to the Flibe blanket. Although any of the tritium recovery systems resulted in realistic figures of engineering design, extensive research based on materialistic and chemical viewpoints is necessary for resolving impurity effects and various interactions in the tritium recovery systems.
研究報告14-2
解説
杉崎 昌和、橋爪 健一
九州大学工学部応用原子核工学科
〒812 福岡市東区箱崎6-10-1
Masayasu SUGISAKI, Kenichi HASHIZUME
Department of Nuclear Engineering, Faculty of Engineering, Kyushu University
Hakozaki, Higashi-ku, Fukuoka-shi 812
(Received August 11, 1994; accepted November 28, 1994)
ABSTRACT
Formulation of electromigration based on irreversible thermodynamics is given, and experimental techniques to determine the effective valence of hydrogen isotopes in metals are explained. Literature data of the effective valence of hydrogen isotopes in metals are extensively surveyed and the data in group-V metals are reviewed in detail. Recent theories to decompose the effective valence into direct and wind valences are reviewed, and the validity of the recent theory to calculate the magnitude of the wind valence of hydrogen isotopes in group-V metals is discussed.
研究報告14-3
論文
長谷川 淳*、堀井 一宏*、松山 政夫**、渡辺 国昭**
*富山大学工学部
**富山大学水素同位体機能研究センター
〒930富山市五福3190
Kiyoshi HASEGAWA*, Kazuhiro HORII*, Masao MATSUYAMA**, and Kuniaki WATANABE**
*Faculty of Engineering, Toyama University
**Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received September 22, 1994; accepted November 28, 1944)
ABSTRACT
The authoes have reported that the oxidation
of tritium is considerably accelerated by irradiation a mixture gas of
HT(H2)-O2 with UV-photons, and this UV-stimulated
HT oxidation is mainly due to the formation of intermediates such as ozone
and activated oxygen species. This suggests that the oxidation will be
much more enhanced in the presence of excess ozone in the reaction system.
To examine this possibility, effects of the
excess ozone on the UV-stimulated HT oxidation was experimentally studied
on the one hand, and reaction mechanisms were investigated by developing
a computer simulation program applicable to the three-component system
of HT(H2)-O2 -O3. The formation rate of
HTO was measured for gasmixtures consisting of O2(75.5 torr),
O3(0.5-2% of O2), H2(0.1-3% of O2)
and HT(H2/HT=12000).
The experiments showed considerable enhancement
of the HTO production rate in the presence of excess ozone by UV-photons
from a low pressure mercury lamp (5W). The time course of the reaction
was reproduced quite well by computer simulation, indicating that the assumed
reaction mechanism is valid. This is also supported by observations that
the computer simulation reproduced the experimentally observed dependence
of ozone decomposition rate on ozone and hydrogen pressures under the UV-irradiation.
Those results showed that UV-stimulated HT oxidation was accelerated by
about 14000 times in the presence of excess ozone. It strongly suggests
that the UV-stimulated oxidation in the presence of excess ozone will be
applicable to tritium handling systems as a non-catalytic tritium removal
method.
研究報告14-4
論文
松山 政夫、渡辺 国昭、諸住 正太郎
富山大学水素同位体機能研究センター
〒930 富山市五福3190
Masao MATSUYAMA, Kuniaki WATANABE and Shotaro MOROZUMI
Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received August 11, 1994; accepted November 28, 1994)
ABSTRACT
Absorption and desorption characteristics of hydrogen were examined for a ZrNi-alloy capsule fabricated to prevent the scater of fine powder. The ZrNi-alloy capsule was fabricated by compression molding of ZrNi-alloy pellet and stainless steel powder mixed with a given amount of magnesium powder. It was found that the fraction of 5% of magnesium was the best for absorption of hydrogen. In addition, it was revealed that the ZrNi-alloy capsule was not broken by hydride formation at the hydrogen concentration of ZrNiH2.2. The characteristics of dissociation pressure on the ZrNi-alloy capsule were almost the same as those on bare ZrNi powder. From those results, it was concluded that the ZrNi-alloy capsule enveloped in the sintered stainless steel over-layers was feasible for preventing the scatter of fine powder of hydrogen storage materials.
研究報告14-5
論文
芦田 完1、渡辺 国昭1、寺下 尚克2、多々 静夫2、池野 進3
1富山大学水素同位体機能研究センター
2富山大学工学部物質工学科
3地域共同研究センター
〒930 富山市五福3190
Kan ASHIDA1, Kuniaki WATANABE1, Maoyoshi TERASHITA2, Sizuo TADA2, Susumu IKENO3
1Hydrogen Isotope Research Center, Toyama University
2Material Science and Engineering, Faculty of Engineering, Toyama University
3Center for Cooperative Research, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received September 7, 1994; accepted November 30, 1994)
ABSTRACT
Electroless Pd plating on Zr3Al2 granules was prepared as a protective layer on the getter alloy surface. The absorption of deuterium obeyed the first order kinetics with respect to the deuterium pressure for both Zr3Al2 and Pd/ Zr3Al2. The rate determining step for absorption was the dissociation reaction of gaseous and/or adsorbed deuterium molecules on the surface. The activation energy was evaluated to be 7.4 and 8.9 kJ/mol (D2) for Zr3Al2 and Pd/ Zr3Al2, respectively. In addition, the durability against impurity gases for deuterium absorption was also demonstrated using CO2 and N2 as impurity gases. Exposure to these impurity gases caused a reduction of the absorption rate of deuterium. The extent of the reduction for Pd/Zr3Al2 was smaller than that for bare Zr3Al2. The effectiveness of the Pd-overlayer against impurity gases was in the order of N2>CO2. The results could be explained in terms of different absorption propertyes of deuterium between Pd and Zr.
研究報告14-6
論文
金坂 績、織田 和宏
富山大学理学部
〒930 富山市五福3190
Isao KANESAKA and Kazuhiro ODA
Faculty of Science, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received September 7, 1994;accepted November 28, 1994)
ABSTRACT
The infrared spectra of polypyrrole contacting with T2O gas were observed for ca. 100 days. After adding T2O(1.2 Ci; isotopic purity: 15%) the band at 2180p-1 was observed, which is assigned to the N-T stretch. Although the bands at 1560 and 1204p-1 were initially strong, they became relatively weak by Tβ-irradiation. On the other hand, the band at 1655 and 1400p-1, as well as 1700p-1, because relatively strong by Tβ-irradiation. This is explained in that the quinonoid-type structure with partially aromatic-type structure decreases and a structure with probable C=N bonds is formed. It was also found that many carbonyl defects are formed on both the atmosphere and Tβ-radiolysis.
研究報告14-7
論文
原 正憲*、金坂 績*、渡辺 国昭**、兜森 俊樹***
*富山大学理学部
**富山大学水素同位体機能研究センター
〒930 富山市五福3190
***日本製綱所且コ蘭研究所
〒051 室蘭市茶津町4
Masanori HARA*, Isao KANESAKA*, Kuniaki WATANABE**, Toshiki KABUTOMORI***
*Faculty of Science, Toyama University
**Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
***The Japan Steel Works, Ltd.
4 Chatsu-cho, Muroran-shi, Hokkaido 051, JAPAN
(Received September 7, 1994; accepted November 28, 1994)
ABSTRACT
Zirconium-alloys such as ZrNi and ZrCo have
been developed so far as promising materials for storage, supply and recovery
of tritium. They, however, easily lose their ability of reversible absorption-desorption
of tritium in the presence of impurity gases such as O2, H2O,
CO2, CO and others. Although we have developed a method to lower
this contamination effect, there is another possibility for the degradation
of their properties by repeated heat cycles in a hydrogen atmosphere.
To examine this possibility, we studied the
changes in the characteristics of those alloys for hydrogen absorption
and desorption owing to the heat cycles in the presence of hydrogen in
a system. The samples were used as grains. They were first exposed to a
hydrogen gas to prepare respective hydrides of a form of ZrMH3,
where M is Ni or Co. Subsequently, the changes in the absorption-desorption
characteristics were measured in a closed system during heat cycles between
room temperature and 600℃.
No significant change in the equilibrium
pressure of hydrogen was observed up to 50 heat cycles for ZrNi. X-ray
diffraction analysis revealed that the sample kept ZrNi structure before
and after the heat cycles. The hydride formed was always ZrNiH3.
Contrarily, ZrCo showed drastic changes in the absorption-desorption characteristics
in 50 heat cycles. X-ray diffraction analysis showed that the ZrCoH3
initially formed was decomposed to ZrHx + ZrCo2. Namely, the
disproportionation of ZrCo took place. It is noteworthy that the disproportionation
reaction did not occur in the absence of hydrogen isotopes in the system.
On account of these observations, it was concluded that the degradation
of absorption-desorption characteristics of ZrCo is due to the ease in
disproportionation, and hence its ability is kept for a large number of
heat cycles, namely storage, supply and recovery operations.
研究報告14-8
論文
小林 徹*、坂本 章*、後藤 克巳*、三宅 均**、松山 政夫**、渡辺 国昭**
**富山大学理学部
**富山大学水素同位体機能研究センター
〒930 富山市五福3190番地
Tohru KOBAYASHI*, Akira SAKAMOTO*, Katsumi GOTO*, Hitoshi MIYAKE**, Masao MATSUYAMA**,Kuniaki Watanabe**
*Faculty of Science, Toyama University
**Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
(Received September 21, 1994; accepted November 28, 1994)
ABSTRACT
Conventional gas chromatographic separation
of hydrogen isotopes is based on the isotope effect on physical adsorption.
It inevitably requires low working temperature, for example liquid nitrogen
temperature. On the other hand, hydrogen isotopes are easily absorbed by
palladium with considerable isotope effects at moderately high temperatures.
This property is useful for gas chromatographic separation of hydrogen
isotopes around room temperature. One problem of this application is the
effects of supporting materials of Pd. The supporting materials often severely
interfere with the isotope separation. In this study, Al2O3
was selected as a model of supporting materials. Its effect on the separation
of hydrogen and deuterium from a 50%H2-50%D2 mixture
gas was examined and compared with support-free Pd.
Pd/Al2O3 packed columns
showed very poor separation above room temperature, whereas considerably
better results were obtained by the support-free Pd. Thermal desorption
study on the adsorption and desorption of deuterium for those materials
revealed that the Al2O3-supported acts as a sink
of deuterium atoms spilled from the Pd surface by forming adsorbed water,
HDO(a), and hydroxyl group, OD(a) with exchange reactions of residual H2O(a)
and /or OH(a). As a consequence, the isotope effect on the adsorption or
adsorption of hydrogen isotopes by Pd was obscured by isotope effects of
the exchange reactions, leading to the poor separation. This study revealed
the importance of hydrophilic supporting materials for the development
of gas chromatographs for hydrogen isotope separation work at room temperature.
研究報告14-9
論文
二村 嘉明*、土谷 邦彦**、今泉 秀樹**、河村 弘**、兜森 俊樹***、脇坂 祐一***
*富山大学水素同位体機能研究センター
〒930 富山市五福3190
**日本原子力研究所
〒311-13茨城県東茨城郡大洗町成田町新堀3607
***株式会社 日本製綱所
〒051 北海道室蘭市茶津町4丁目
Yoshiaki FUTAMURA*, Kunihiko TSUCHIYA**, Hideki IMAIZUMI**, Hiroshi KAWAMURA**, Toshiki
KABUTOMORI***, Yuichi WAKISAKA***
*Hydrogen Isotope Research Center, Toyama University
Gofuku 3190, Toyama 930, JAPAN
**Japan Atomic Energy Research institute
3607 Shinbori, Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki-ken 311-13, JAPAN
***The Japan Steel Works, Ltd.
4 Chatsu-cho, Muroran-shi, Hokkaido 051, JAPAN
(Received September 21, 1994; accepted November 28, 1994)
ABSTRACT
In situ irradiation test of fusion blanket is planed in JMTR using lithium ceramics and beryllium as tritium breeders and neutron multipliers, and it is necessary for the recovery of tritium gas to develop metal getters. Characteristic of several materials were estimated and Zr9Ni11 alloy, chosen in the report, was one candidate for a metal getter. It has a variety of advantages as compared to other metal getters:
Zr9Ni11 alloy was fabricated
and the equilibrium dissociation pressure of hydrogen was measured and
evaluated on amounts of hydrogen absorption (H/M) at 20, 100, 200 and 300
℃. It was evident from this measurement that Zr9Ni11
alloy had broad and stable plateaus when H/M was more than 0.33 (50 cm3/g).
The equilibrium dissociation pressure of Zr9Ni11
alloy was less than 10-4Pa within H/M=0.13 (20cm3/g).
These results thus show Zr9Ni11
alloy to be a preferable material for recovery of tritium gas.