N. Yoshida¹, N. Yugami², Y. Kimura², T. Fujiwara¹, K. Araki¹, R. Yoshihara¹, H. Watanabe¹, M. Tokitani³, S. Masuzaki³, Y. Hatano⁴, M. Matsuyama⁴, Y. Oya⁵, K. Okuno^5
1Research Institute for Applied Mechanics, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan
²Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan
³National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292, Japan
⁴ Hydrogen Isotope Research Center, Organization for Promotion or Research, University of Toyama, Gofuku, Toyama 930-8555, Japan
⁵Faculty of Science, Shizuoka University, Ohya, Suruga-ku, Shizuoka 422-8529, Japan

Abstract
Modification of the plasma facing surface of LHD and its effects on the retention and desorption of He were examined by exposing 316L stainless steel coupons to LHD plasmas. In the erosion dominant area, formation of dense He bubbles and mixing of deposited impurities (C, O, Fe, Cr, Ni) occurred in a subsurface region of about 20 nm-thick. In the deposition dominant area, the surface was covered by a porous carbon rich layer. Retention of He was saturated in both areas. In the erosion dominant area, He was trapped by the radiation-induced defects formed in the very thin subsurface region. The concentration of He trapped in the impurity deposition (He/C) in the deposition dominant area was estimated to be 0.9%.

Akira Taguchi^*, Tomohiro Ozaki
Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan

Abstract
Pt nanoparticles sputter-deposited on α-Al₂O₃ support were investigated by FE-SEM measurements and CO chemisorption studies. Pt nanoparticles formed in the early stages of sputter deposition were well isolated, and the particle size distribution of Pt nanoparticles evaluated by FE-SEM measurements was narrow. Longer sputter deposition resulted in growth and coalescence of Pt nanoparticles. Such a transition of Pt from nanoparticles to film by sputter deposition was properly evaluated by CO chemisorption studies.

Masao Matsuyama^a,*, Shinsuke Abe^a, and Katsutoshi Tusima^b
aHydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan
^bFaculty of Science, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan

Abstract
The applicability of a freezing technique to the reduction of the volume of waste water contaminated with radioactive materials such as ¹³⁷Cs, ⁹⁰Sr, and ⁹⁰Y has been examined. Simulated waste water containing a trace amount of added non-radioactive cesium (ca. 20 wt. ppm) was used in this study. A cooling pipe was immersed in the simulated waste water, and the cesium concentration in the ice produced around the pipe and the residual water were measured by an atomic absorption spectrometry after a given time. The temperature of the cooling fluid flowed through the pipe was regulated below 273 K using a conventional cooling device. The cesium concentration in the formed ice was found to be more 200 times lower than that in the initial simulated waste water. The same results were obtained for waste water with added radioactive cesium (¹³⁷Cs), and similar phenomena observed for simulated water containing strontium, yttrium, and NaCl with cesium. It was suggested that the cesium concentration is strongly affected by the number of bubbles in the ice, crystal size of the ice, and the total impurity concentration in the waste water. Our results indicate that freezing is a promising candidate technique for the processing of radioactive waste water.

Masanori HARA^a,*, Fumina NAKANO^a, Shinsuke ABE^a, Masato NAKAYAMA^a
aHydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan

Abstract
In liquid scintillation counting, quenching correction of the sample is indispensable for measuring radioactivity. The chemical quenching is corrected by a quenching correction curve obtained with a quenched standard set. In this work, the applicability of a quenched standard set to various chemical substances was studied using angle distributions in 2D scintillation spectra. The quenching dependence of the angle distributions measured from various chemical quenchers was found to coincide. Namely, the relationship between the chemical quenching and the angle distribution is maintained whatever chemical substances is used. This result indicates that a single quenched standard can be used to correct for the effect of various chemical quenchers.

Hideki Nishizawa, Mitsuhiro Inoue, Takayuki Abe
Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan

Abstract
Lithium phosphorous oxynitride (LiPON) electrolytes for solid-state lithium batteries were prepared using the polygonal barrel-sputtering system. When sputtering was carried out at an N₂ gas pressure of 4 Pa and an AC power of 100 W for 120 min using a Li₃PO₄ target plate, a worm-like deposition was formed on the planer silicon substrate. An N1s peak was observed at around 400 eV in the X-ray photoelectron spectroscopy survey spectrum of the sputtered sample. This N1s peak was deconvoluted into two peaks: one at 397.4 eV ascribed to P-N<P bond formation and the other at 399.0 eV reflecting P-N=P bond formation. Based on these data, the formed deposit was assigned to LiPON. The ion conductivity of the prepared LiPON was evaluated by impedance measurements. A semicircle was obtained in the Cole-Cole plot, from which the ion conductivity was determined to be 1.8 × 10^-6 S cm^-2, close to those of typical LiPON films in the literature (1.7 × 10^-6-6.4 × 10^-6 S cm^-2). Thus, LiPON films can be prepared by the polygonal barrel-sputtering system.

Satoshi Akamarua^a,*, Saki Furusato^a, Masanori Hara^a, Masao Matsuyama^a
Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan

Abstract

To understand the hydrogen absorption and desorption behaviors of Pd under air, we performed real time measurements of the electrical resistance of Pd under gas mixture with various oxygen contents. The hydrogen absorption rate was independent of oxygen concentration. Conversely, the hydrogen desorption rate in the presence of oxygen was faster than that without oxygen, suggesting that the additional desorption path including water formation reaction appears in the hydrogen desorption process in the presence of oxygen. The hydrogen concentration in Pd at equilibrium decreased with increasing oxygen concentration in gas phase because the hydrogen adsorption sites become partially occupied by oxygen atoms.