発表論文 2006年

[2006_01]

Interactions between molten Flibe and metallic Be

M. Haraa, Y. Hatanoa, M.F. Simpsonb, G.R. Smolikc, J.P. Sharpec, Y. Oyad, K. Okunoe, M. Nishikawaf, T. Teraid, S. Tanakad, R.A. Anderlc, D.A. Pettic, D.-K. Szeg

a Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

b Argonne National Laboratory - West, P.O. Box 2528, Idaho Falls, ID 83403-2528, USA

c Idaho National Engineering and Environmental Laboratory (INEEL), P. O. Box 1625, Idaho Falls, ID 83415-2218, USA

d The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan

e Shizuoka University, Ohya 836, Shizuoka 422-8529, Japan

f Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

g University of California, San Diego, La Jolla, CA 92093-0427, USA

Abstract

[2006_02]

Quantitative measurement of beryllium-controlled redox of hydrogen fluoride in molten Flibe

M.F. Simpsona, G.R. Smolika, J.P. Sharpea, R.A. Anderla, D.A. Pettia, Y. Hatanob, M. Harab, Y. Oyac, S. Fukadad, S. Tanakac, T. Teraic, D.-K. Szee

a Idaho National Laboratory, P.O. Box 2528, Idaho Falls, ID 83403, United States

b Hydrogen Isotope Research Center, Toyama University, Japan

c University of Tokyo, Japan

d Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Japan

e University of California at San Diego, United States

Abstract

[2006_03]

Applicability of β-ray-induced X-ray spectrometry to in situ measurements of tritium retention in plasma-facing materials in ITER

M. Matsuyamaa, Y. Torikaia, N. Bekrisb, M. Gluglab, A. Erbec, W. Naegelec, N. Nodad, V. Philippse, P. Coadf, K. Watanabea

a Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

b Tritium Laboratory, FZK, EURATOM Association, D-76021 Karlsruhe, Germany

c Intitute for Materials Research II, FZK, EURATOM Association, D-76021 Karlsruhe, Germany

d National Institute for Fusion Science, Oroshi-cho, Toki-shi, Gifu 509-5292, Japan

e Institute for Plasma Physics, FZJ, EURATOM Association, TEC, 52425 Julich, Germany

f EURATOM/UKAEA Fusion Association, Culham Science Center, Abingdon, Oxon OX14 3DB, UK

Abstract

    Applicability of β-ray-induced X-ray spectrometry (BIXS) for in situ measurements of tritium retention by plasma-facing materials in ITER was examined using two γ-emitters and a divertor tile with metallic supports employed during D-T fusion experiments in JET. Measurements of the tile with a γ-emitter showed that the presence of the γ-field has no influence in the shape of the β-ray-induced X-ray spectra, although the whole intensity in the observed energy region was dependent on radioactivity of the γ-emitters. To simulate more accurately the in-vessel environment of PFMs, one of the divertor tiles with metallic supports was subjected to BIXS measurements. Although the metallic supports were gamma active, no significant effect was observed on the recorded X-ray spectrum. These results clearly indicate that BIXS can be applied to in situ measurements of tritium retention by PFMs with a simple shielding of the X-ray detector.

Keywords: Tritium retention; In situ measurement; BIXS; Plasma-facing materials; ITER

[2006_04]

JUPITER-II molten salt Flibe research: An update on tritium, mobilization and redox chemistry experiments

D.A. Pettia, G.R. Smolika, M.F. Simpsona, J.P. Sharpea, R.A. Anderla, S. Fukadab, Y. Hatanoc, M. Harac, Y. Oyad, T. Teraid, D.-K. Szee, S. Tanakad

a Fusion Safety Program Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415, USA

b Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan

c Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

d University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

e University of California at San Diego, La Jolla, CA 92093-0427, USA

Abstract

    The second Japan/US Program on Irradiation Tests for Fusion Research (JUPITER-II) began on April 1, 2001. Part of the collaborative research centers on studies of the molten salt 2LiF-BeF2 (also known as Flibe) for fusion applications. Flibe has been proposed as a self-cooled breeder in both magnetic and inertial fusion power plant designs over the last 25 years. The key feasibility issues associated with the use of Flibe are the corrosion of structural material by the molten salt, tritium behavior and control in the molten salt blanket system, and safe handling practices and releases from Flibe during an accidental spill. These issues are all being addressed under the JUPITER-II program at the Idaho National Laboratory in the Safety and Tritium Applied Research (STAR) facility. In this paper, we review the program to date in the area of tritium/deuterium behavior, Flibe mobilization under accident conditions and testing of Be as a redox agent to control corrosion. Future activities planned through the end of the collaboration are also presented.

Keywords: JUPITER-II; Flibe; Molten salt

[2006_05]

Monitoring of tritium in diluted gases by detecting bremsstrahlung X-rays

W.M. Shua, M. Matsuyamab, T. Suzukia, M.F. Nishia

a Tritium Engineering Laboratory, Japan Atomic Energy Research Institute, Ibaraki 319-1195, Japan

b Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

Abstract

    For developing an alternative mean for on-line and real-time tritium monitoring, the method of detecting bremsstrahlung X-rays was examined by measuring the counting rate of bremsstrahlung X-rays as a function of pressure in two mixed tritium gases diluted with hydrogen or helium. At a constant tritium partial-pressure ratio of 0.010, the relationship between the counting rate of bremsstrahlung X-rays, X (cpm) and the total pressure, P (Pa) can be expressed as X = 4.1×105 (1-e-4.0 P/100,000). The counting rate depends only on tritium partial-pressure and the total pressure if the mixed gases contain no other species but hydrogen isotopes and helium isotopes. In addition, the relation between X and P can be simplified to a linear function in the low-pressure region of P<<2.5×104 Pa.

Keywords: Tritium; Monitoring; Bremsstrahlung X-rays; Absorption coefficient

[2006_06]

Development of a tritium separation process using SDGC

Y. Morimotoa, S. Kojimaa, T. Sasakia, M. Matsuyamab, M. Harab, S. Akamarub, M. Numataa, T. Katoa, K. Watanabeb

a JGC Corporation, 2205 Narita-cho, Oarai-machi, Higashiibaraki-gun, Ibaraki 311-1313, Japan

b Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

Abstract

    A self-developing gas chromatography (SDGC) process using a column packed with Pd-at.% Pt alloy powder was studied for hydrogen isotope separation at room temperature. Separation experiments of a deuterium-tritium (50% D2-50% T2) mixture were carried out using the same SDGC column. The concentrations of tritium in the recovered hydrogen isotope gas were 80 and 75% at 50 and 70% recovery of tritium, respectively. The result of the deuterium-tritium separation experiments suggested considerable potential for the applicability of the SDGC column to the D-T separation process at room temperature.

Keywords: Self-developing gas chromatography; Pd-Pt alloy; Tritium; Isotope separation

[2006_07]

Influence of oxygen and carbon on performance of superpermeable membranes

Y. Hatanoa, A. Livshitsb, Y. Nakamurac, A. Busnyukb, V. Alimovb, C. Hiromia, N. Ohyabuc, K. Watanabea

a Hydrogen Isotope Research Center, Toyama University, Toyama 930-8555, Japan

b Bonch-Bruyevich University, 61 Moika, St. Petersburg 191186, Russia

c National Institute for Fusion Science, Oroshi-cho 322-6, Toki 509-5292, Japan

Abstract

    In order to understand the applicability of superpermeable membranes for tritium recovery from fusion exhaust gas containing impurities, the influence of oxygen and carbon on the performance of Nb and V membranes was examined by laboratory scale experiments. No significant degradation due to oxygen was observed if the membrane temperature was sufficiently high, i.e. above 700 K, and the bulk oxygen concentration was below 1.5 at.%. It was also possible to avoid the influence of carbon deposition by the operation at high temperatures through the conversion of carbon deposited layer into carbide layer.

Keywords: Superpermeation; Tritium; Recovery; Niobium; Vanadium

[2006_08]

Effect of a magnesium depletion on the Mg-Ni-Y alloy hydrogen absorption properties

M. Hara, S. Morozumi, K. Watanabe

Hydrogen Isotope Research Center, Toyama University, Toyama 930-8555, Japan

Abstract

    To improve the hydrogen absorption properties of Mg2Ni, three kinds of specimens were prepared. They were denoted as MGNIY, DeMg-MGNIY and DeMg-MIX. The first one was a cast Mg-Ni-Y alloy, the second was prepared by vacuum heating of MGNIY to remove some part of Mg and the third was prepared by vacuum heating of a mixture of pulverized Mg-Y and Mg2Ni. The term DeMg denotes removal of Mg by vacuum heating. These samples were characterized by XRD, SEM and EPMA and found to be composed of Mg, Mg2Ni and crystallographically unknown phases. Each material was found to have its own distribution of yttrium. The composition of the crystallographically unknown phase was determined by EPMA to be MgYNi3. Yttrium-alloying and subsequent DeMg treatment caused a significant improvement in the hydrogen absorption rate. It showed hydrogen uptake amounting to about 3 mass % for DeMg-MGNIY at 473K in 80ks, although the improvement at room temperature could not be distinguished from that of Mg2Ni. MGNIY gave similar absorption properties with those of DeMg-MGNIY at 473K, but showed significantly slower absorption rate than Mg2Ni at room temperature. The properties of DeMg-MIX were found to be similar to those of Mg2Ni at both temperatures. On account of the sample characterization, it was concluded that the improvement in hydrogen uptake by DeMg-MGNIY and MGNIY at 473K was due to their specific yttrium-distribution and catalytic activity.

Keywords: Mg-based alloys; Hydrogen absorption; Magnesium depletion; Mg2Ni; Yttrium-alloying

[2006_09]

ステンレス鋼中のトリチウムの分布

鳥養祐二, 村田大樹, Ralf-Dieter PENZHORN, 赤石憲也, 渡辺国昭, 松山政夫

Hydrogen Isotope Research Center, Toyama University, Toyama 930-8555, Japan

Abstract

    To investigate the behavior of hydrogen uptake and release by 316 stainless steel (SS316), as-received and finely polished stainless steel specimens were exposed at 573K to tritium gas diluted with hydrogen. Then tritium concentration in the exposed specimens was measured as a function of depth using a chemical etching method. All the tritium concentration profiles showed a sharp drop in the range of 10μm from the top surface up to the bulk. The amount of tritium absorbed into the polished specimens was three times larger than that into the as-received spacimen. However, the polishing effects disappeared by exposing to the air for a long time.

[2006_10]

Detritiation of type 316 stainless steel by treatment with liquids at ambient temperature

R.-D. Penzhorn, Y. Torikai, M. Matsuyama, K. Watanabe

Hydrogen Isotope Research Center, Toyama University, Toyama 930-8555, Japan

Abstract

   The detritiation efficiency of type 316 stainless steel (SS316) using liquids reagents (distilled deionized water, concentrated aqueous ammonia or a diluted hydrochloric acid/nitric acid mixture) was investigated at ambient temperature by means of liquid scintillation counting (LSC) and β-ray-induced ×-ray spectrometry (BIXS). After a fast initial removal of tritium trapped on the outermost surface of SS316 with a rate in the order water < ammonia < acid mixture a slow chronic liberation of tritium into all three liquids sets in. First results indicate that chronic release occurs with a rate of approx. 0.2% per day. The long-term release was found to be largely independent from the kind of liquid agent into which the metal is submerged and from the initial loading of the SS316 specimen. From a practical point of view, the release rate of tritium into liquids is too slow for conditioning applications. Complementary evidence for the occurrence of a chronic liberation of tritium from SS316 into air at ambient temperature was obtained from tritium depth profiling of aged specimens by acid etching.

[2006_11]

Magnetic properties of palladium and palladium-platinum alloy of various hydrogen content

Masanori Haraa, Junichi Sakuraib, Satoshi Akamarua, Kuniaki Watanabea, Katsuhiko Nishimurab, Katsunori Morib, Masao Matsuyamaa

aHydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan

bFaculty of Engineering and Science, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan

Abstract

    Magnetic properties of palladium and palladium-platinum alloy (Pd-Pt) of different hydrogen content were measured in a hydrogen atmosphere at ambient temperature using a superconducting quantum interference device (SQUID) magnetometer. It was found that the magnetic susceptibility of Pd and Pd-Pt alloy decreased with increasing hydrogen content. These results were attributed to a change in the electronic structure of the valence band. Increasing hydrogen content in Pd and Pd-Pt alloy causes the Fermi level to rise and the density of states at Fermi level to decrease. Since the magnetic susceptibility is proportional to the density of states at the Fermi level, the magnetic susceptibility decreases with increasing hydrogen content. The magnetic susceptibility of Pd-Pt was smaller than that of Pd over the whole hydrogen content range. This was ascribed to the higher position of the Fermi level of Pd-Pt than that of Pd.

Keywords: palladium alloy; hydride; Fermi level; density of states; magnetic susceptibility

[2006_12]

Surface coating of small SiO2 particles with TiO2 thin layer by using barrel-sputtering system

Satoshi Akamaru, Shingo Higashide, Masanori Hara, Takayuki Abe

Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

Abstract

    Surface coating of small SiO2 particles with a thin TiO2 layer was carried out by using a hexagonal barrel-sputtering system. In order to determine suitable sputtering conditions, the TiO2 layer was deposited on a glass substrate by reactive sputtering under given total pressures, oxygen fractions, and substrate temperatures. The analysis of X-ray diffraction patterns and ultraviolet-visible absorption spectra showed that the preparation of a TiO2 layer with the rutile phase requires a high total pressure at room temperature whereas that with the anatase phase requires a moderate total pressure at 498 K. The surface coating of SiO2 particles by TiO2 layer was performed under the conditions suitable for either the rutile or anatase phase. It was found from scanning electron microscope, energy-despersion spectrometer, and ultraviolet-visible absorption measurements that the surface of SiO2 particles was successfully coated with a thin uniform TiO2 layer with the rutile or anatase phase.

Keywords: Titanium oxide; Barrel-sputtering system; Surface coating; Powdery materials

[2006_13]

Phase transition and electrochemical capacitance of mechanically treated manganese oxides

Akira Taguchi, Sachio Inoue, Satoshi Akamaru, Masanori Hara, Kuniaki Watanabe, Takayuki Abe

Hydrogen Isotope Research Center, Toyama University, Gofuku 3190, Toyama 930-8555, Japan

Abstract

    Mechanical grinding (MG) leads to a sequential phase transition of γ-MnO2 to form the thermodynamically stable α-Mn2O3 and, subsequently, Mn3O4 depending on the duration of MG treatment. By MG treatment for 150h, α-Mn2O3 became a predominant species. A subsequent transition to Mn3O4 was observed on further MG treatment for 200h. The particle size of the resultant manganese oxides was reduced to as small as 20nm after 300h of MG treatment. The change in the specific capacitance of manganese oxides obtained was monitored by XRD and electrochemical experiments. It was observed that the specific capacitance of MG-treated manganese oxides depends on the amount of γ-MnO2 left without phase transition.

Keywords: Manganese oxides; Phase transition; Mechanical grinding; Supercapacitor

[2006_14]

A Newly Developed Non-Destructive Tritium Measurement Technique and Its Application to V-4Cr-4Ti Alloy

LIU Xiang1, CHEN Xue2, H.HOMMA3, Y.HATANO3, M.MATSUYAMA3

1Southwestern Institute of Physics, Chengdu 610041,China

2Sichuan General Fire Brigade, Chengdu 610072,China

3Hydrogen Isotope Research Centre, Toyama University, Gofuku3190, Toyama 930-8555, Japan

Abstract

    A non-destructive and in-situ technique for the measurement of tritium in materials, namely β-ray-induced X-ray spectrometry(BIXS), has been developed recentry. In the present study a V-4Cr-4Ti alloy was pre-heated at 1000℃ for 2 h to form a recrystallization structure before the tritium absorption experiments were conducted. Firstly the hydrogen isotope gas was chamber. Then hydrogen isotope absorption tests of V-4Cr-4Ti alloy were performed at 400℃ and the atomic concentration of hydrogen isotope in V-4Cr-4Ti alloy was estimated as 0.17% with a tritium content of approximately 2.5 ppm. Experimental results indicate that BIXS is a quite useful tool for quantitatively measuring the tritium content and tritium exist in the pre-heated V-4Cr-4Ti alloy.

Keywords: tritium, V-4Cr-4Ti, β-ray-induced X-ray spectrometry, tritium measurements