Development of methods for reprocessing and reuse of tritium breeder materials in broader approach activities

Hoshino, Tsuyoshi

Journal of Nuclear Materials, 442(1-3), p.S425 - S428, 2013/11

https://doi.org/10.1016/j.jnucmat.2013.03.009

Development of reprocessing and reuse of this spent breeder including unburned Li is important from viewpoint of effective utilization Li as a limited resource. This activity has been started between Japan and the EU in the Broader Approach activities. The effect of solvent on dissolution of LiTiO powder was evaluated. LiTiO powder with 99.9% purity was prepared as a starting powder. Solubility of Li was evaluated from the measurement result of the Li content in solution by ICP (inductively coupled plasma) atomic emission spectrometry. Peroxide hydrogen (HO) was selected as solvent. Most of LiTiO was soluble in room temperature, and then the solubility of Li were larger than 90%.

The Effect of sintering time on synthesis of plasma sintered beryllides

Kim, Jae-Hwan; Nakamichi, Masaru

Journal of Nuclear Materials, 442(1-3), p.S461 - S464, 2013/11

https://doi.org/10.1016/j.jnucmat.2012.10.013

First-principles thermodynamic calculations of diffusion characteristics of impurities in -iron

Tsuru, Tomohito; Kaji, Yoshiyuki

Journal of Nuclear Materials, 442(1-3), p.S684 - S687, 2013/11

https://doi.org/10.1016/j.jnucmat.2013.03.051

Since the solute impurities have an effect on the embrittlement through segregation under irradiation, the solute stability of impurity elements is of considerable importance. In the present study, the diffusion characteristics of large-radius impurities in -Fe are investigated by first principles calculations. According to the classical diffusion and transition state theories, diffusion coefficient were evaluated nonempirically. The vacancy formation energy and binding energy between impurity and vacancy were obtained by first principles density functional theory (DFT) calculations. And the migration energy was calculated by nudged elastic band method collaborated with DFT. Consequently, it is confirmed that the binding energy between large-radius impurity and vacancy is larger than that with equivalent size of the solvent element, and that the migration enthalpies of these impurities are quite small compared with self diffusion.

Microsegregation in a F82H plate

Sakasegawa, Hideo; Tanigawa, Hiroyasu

Journal of Nuclear Materials, 442(1-3), p.S18 - S22, 2013/11

https://doi.org/10.1016/j.jnucmat.2013.01.322

Through the Broader Approach (BA) activity in Japan, F82H-BA07 heat of 5 tons prepared applying electrosrag remelting (ESR) has been studied as a step toward a larger-scale melting about 20 tons. From the result of elemental mapping images using electron probe microanalysis (EPMA), micro-segregation of at least four metallic elements such as chromium, tungsten, vanadium and manganese was found as stripes parallel to the hot rolling direction. In the case of tungsten segregation, the maximum difference of content was about 1.0 wt% between the observed stripes. This difference could cause differences in nano-metric structures between stripes, and affect mechanical properties. In this presentation, we discuss how much micro-segregation should be decreased considering effects of micro-segregation on nano-metric structures and mechanical properties in addition to the result of optimization of homogenizing condition.

Effect of cation exchange on hydrogen adsorption property of mordenite for isotope separation

Kawamura, Yoshinori; Iwai, Yasunori; Munakata, Kenzo*; Yamanishi, Toshihiko

Journal of Nuclear Materials, 442(1-3), p.S455 - S460, 2013/11

https://doi.org/10.1016/j.jnucmat.2012.11.003

Zeolite easily exchanges its cation to another. In this work, synthetic mordenite type zeolite (Na-MOR) was used as start material. And, its cation (Na) has been exchanged by Li, K, Mg and Ca. Then, adsorption capacities of H and D on them were investigated at 77 K, 159 K, 175 K and 195 K. Adsorption capacities on Li-MOR and Ca-MOR became larger than that on Na-MOR at low pressure range. Oppositely, that on K-MOR became smaller. In case of alkaline metal, cation with small atomic number may lead to large adsorption capacity.

Mechanical properties of friction stir welded 11Cr-ferritic/martensitic steel

Yano, Yasuhide; Sato, Yutaka*; Sekio, Yoshihiro; Otsuka, Satoshi; Kaito, Takeji; Ogawa, Ryuichiro; Kokawa, Hiroyuki*

Journal of Nuclear Materials, 442(1-3), p.S524 - S528, 2013/09

https://doi.org/10.1016/j.jnucmat.2012.10.038

Friction stir welding was applied to the wrapper tube materials, 11Cr-ferritic/martensitic steel, intended for fast reactors and defect-free welds were successfully produced. Then, the mechanical and microstructural properties of the friction stir welded steel were investigated. The hardness values of the stir zone were about 550 Hv, and they had hardly any dependence on the rotational speed, although they were much higher than that of the base material. However, tensile strengths and elongations of the stir zones were better at 298 K, compared to those of the base material. These excellent tensile properties were attributable to the fine grain formation during friction stir welding. A part of this study is the result of "Friction stir welding of the wrapper tube materials for Na fast reactors" carried out under the Strategic Promotion Program for Basic Nuclear Research by the Ministry of Education, Culture, Sports, Science and Technology of Japan.

Engineering design of contact-type liquid level sensor for measuring thickness validation of liquid lithium jet in IFMIF/EVEDA lithium test loop

Kanemura, Takuji; Kondo, Hiroo; Suzuki, Sachiko*; Hoashi, Eiji*; Yamaoka, Nobuo*; Horiike, Hiroshi*; Furukawa, Tomohiro; Ida, Mizuho; Nakamura, Kazuyuki; Matsushita, Izuru*; et al.

Fusion Science and Technology, 62(1), p.258 - 264, 2012/07

https://doi.org/10.13182/FST12-A14144

In the Engineering Validation and Engineering Design Activities (EVEDA) project of the International Fusion Materials Irradiation Facility (IFMIF), which is one of the Broader Approach (BA) activities, thickness variation of a liquid lithium (Li) jet simulating the IFMIF Li target is planned to be measured in the EVEDA Li Test Loop (ELTL). For this purpose, a contact-type liquid level sensor was developed, which can detect contacts between a probe and Li. Analysis of the contact signals yields average jet thickness and amplitude distribution. One of the key development requirements is to drive the probe by 0.1 mm step with positioning accuracy of 0.01 mm under the vacuum condition of 10Pa. To satisfy such a requirement, the sensor's own weight load and moment load were calculated, and based on those calculation results a powerful motor and a friction-reduced ball screw were selected and strong structure was adopted. We have successfully completed the design work of the sensor.

Overview of materials research and IFMIF-EVEDA under the Broader Approach framework

Nishitani, Takeo; Tanigawa, Hiroyasu; Yamanishi, Toshihiko; Clement Lorenzo, S.*; Baluc, N.*; Hayashi, Kimio; Nakajima, Noriyoshi*; Kimura, Haruyuki; Sugimoto, Masayoshi; Heidinger, R.*; et al.

Fusion Science and Technology, 62(1), p.210 - 218, 2012/07

https://doi.org/10.13182/FST12-A14137

Recent progress in the material related researches and the IFMIF/EVEDA project, which are carried out under the Broader Approach (BA) framework, is reported. In the International Fusion Energy Research Center (IFERC) project of BA, the R&D building was completed March 2010 at the Rokkasho BA site. R&Ds on reduced activation ferritic/ martensitic (RAFM) steels as structural material, SiC/SiC composites as a flow channel insert material and/or alternative structural material, advanced tritium breeders and neutron multipliers, and tritium technology relevant to the DEMO operational condition are progressed in Japan and EU. In the IFMIF/EVEDA project, the fabrication of the injector for the IFMIF prototype accelerator was completed at the CEA Saclay, and the first proton beam was obtained in May, 2011. The IFMIF lithium target test loop was completed in March 2011, and a lithium flow of 5 m/s was obtained.

Effects of carbon impurity on microstructural evolution in irradiated -iron

Abe, Yosuke; Suzudo, Tomoaki; Jitsukawa, Shiro; Tsuru, Tomohito; Tsukada, Takashi

Fusion Science and Technology, 62(1), p.139 - 144, 2012/07

https://doi.org/10.13182/FST12-A14126

Static and dynamic interactions between SIA loops and carbon impurities as a major impurity in -iron was studied using atomic-scale computer simulations to clarify possible mechanisms of trapping of SIA loops by carbon impurities. It was found that bindings of carbon-vacancy complexes with SIA loops are so strong when they locate inside the loop habit plane. This situation would be realized below 450 K at which carbon-vacancy complexes become to dissociate. At higher temperatures, it can be expected that the dissociated interstitial carbon atoms tend to migrate towards the loop periphery due to the internal stress field associated with SIA loops, and this could attribute to the continuous 1D motion of SIA loops with dragging impurities as observed by experiments. A long-term microstructural evolution induced by radiation damage was also simulated by taking into account the trapping and detrapping rates of SIA loops deduced from the knowledge obtained in this study.

Analysis of test matrix and design status of test modules of IFMIF

Wakai, Eiichi; Kikuchi, Takayuki; Yokomine, Takehiko*; Yamamoto, Michiyoshi; Soldaini, M.*; Polato, A.*

Fusion Science and Technology, 62(1), p.246 - 251, 2012/07

https://doi.org/10.13182/FST12-A14142