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.

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.

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
(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.

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
^*富山大学トリチウム科学センター
〒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 ZrNiH_2.2. 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.

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 IKENO^3
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.

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 2180㎝^-1 was observed, which is assigned to the N-T stretch. Although the bands at 1560 and 1204㎝^-1 were initially strong, they became relatively weak by Tβ-irradiation. On the other hand, the band at 1655 and 1400㎝^-1, as well as 1700㎝^-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.

原　正憲^*、金坂　績^*、渡辺　国昭^**、兜森　俊樹^***
富山大学トリチウム科学センター
^*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㈱室蘭研究所
〒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.

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

Hitoshi MIYAKE, Masao MATSUYAMA, Kuniaki WATANABETohru 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.

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:

-Good characteristics similar to uranium (U)

-Easy to handle

-Incombustible materials

 

　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.