• Transactions of the Korean hydrogen and new energy society
• /
• v.18 no.4
• /
• pp.399-405
• /
• 2007

The hyper-eutectic Mg-33.5%Ni alloy was rapidly solidified by melt spinning process. The melt-spun Mg-33.5%Ni has amorphous structure and crystallization occurred above $162^{\circ}C$. The hydriding and dehydriding rates of melt-spun Mg-33.5%Ni increased with cycle and high rate of hydrogen storage occurred at 3rd cycle. The maximum hydrogen amount absorbed in melt-spun Mg-33.5%Ni at $300^{\circ}C$ is about 4.5%.

• Nuclear Engineering and Technology
• /
• v.56 no.3
• /
• pp.824-831
• /
• 2024

In order to investigate the occurring processes during long-term dry storage of spent fuel assemblies, a joined project called SPIZWURZ, between the Karlsruhe Institute of Technology and the Gesellschaft für Anlagen-und Reaktorsicherheit (GRS), was started. Aim of the SPIZWURZ project is the determination and quantification of the influence of texture and elastic strain on diffusion and solubility of hydrogen in three different zirconium alloys used in western Europe during a long-term cooling transient (1 K/d) starting at 400 ℃. The strain in the cladding of an irradiated spent fuel rod shall be measured. Models predicting the formation of radial oriented hydrides will be validated, improved, and implemented in the GRS fuel rod performance code TESPA-ROD. This paper describes the SPIZWURZ project and already obtained first results.

• Transactions of the Korean hydrogen and new energy society
• /
• v.15 no.3
• /
• pp.250-256
• /
• 2004

Magnesium and its alloys have the high potential as hydrogen storage materials because of their highest hydrogen storage capacity, low density and abundant resources. But poor kinetic properties of hydriding and dehydriding and high working temperature have limited their practical applications. In this study, the Mg-Ni binary alloys with different amount of Ni were produced by gravity casting and characterized in order to investigate the relationship between the microstructures and hydriding properties. The maximum hydrogen absorption capacity decreased, but the absorption kinetics increased with Ni content. The difference in the absorption kinetics was resulted from the differences in the sort and shape of primary solid phases and eutectic microstructure.

• Carbon letters
• /
• v.10 no.1
• /
• pp.19-22
• /
• 2009

In this work, the hydrogen storage behaviors of carbon nanotubes (CNTs)/metal-organic frameworks-5 (MOF-5) hybrid composites (CNTs/MOF-5) were studied. Hydrothermal synthesis of MOF-5 was conducted by conventional convection heating using 1-methyl-2-pyrrolidone (NMP) as a solvent. Morphological characteristics and average size of the CNTs/MOF-5 were also obtained using a scanning electron microscopy (SEM). The pore structure and specific surface area of the CNTs/MOF-5 were analyzed by N2/77 K adsorption isotherms. The capacity of hydrogen storage of the CNTs/MOF-5 was investigated at 298 K/100 bar. As a result, the CNTs/MOF-5 had crystalline structures which were formed by hybrid synthesis process. It was noted that the CNTs/MOF-5 can be potentially encouraging materials for hydrogen adsorption and storage applications at room temperature.

• Transactions of the Korean hydrogen and new energy society
• /
• v.26 no.2
• /
• pp.120-126
• /
• 2015

Recently, the ever-increasing use of fossil fuels for rapid industrial development and population significantly caused an environment pollution and global warming such as climate change. So research and development of sustainable and eco-friendly energy have been performed. Especially the interest in nuclear fusion fuel was significantly increased from the developed countries. The system of fusion energy production was tritium separation, storage and delivery, and purification. Republic of Korea is in charge of Storage and Delivery System (SDS) in the International Thermonuclear Experimental Reactor (ITER). Welding part of the SDS bottles for storing the tritium is known to be susceptible to hydrogen embrittlement. In this study, conducted a study for the relaxation of the stability and hydrogen embrittlement of the weld area. The hydrogen heat treatment was processed through the Pressure-Composition-Temperature (PCT) device according to the time variation. Also mechanical properties such as impact test and hardness test according to using the alkaline cleaning liquid for hydrogen embrittlement relief and the fracture was observed by scanning electron microscopy (SEM) after the mechanical properties evaluation.

• Transactions of the Korean hydrogen and new energy society
• /
• v.22 no.6
• /
• pp.780-786
• /
• 2011

Mg hydride had high hydrogen capacity (7.6%), lightweight and low cost materials and it was promising hydrogen storage material at high temperature. However, commercial applications of the Mg hydride are currently hindered by its high absorption/desorption temperature, and very slow reaction kinetics. one of the approaches to improve the kinetic is $MgH_x$ intermixed with carbon. And it shows that carbon and carbon allotropes have a beneficial effect on hydrogen sorption in Mg. The graphene is a kind of carbon allotropes which is easily desorbed reaction at low temperatures because its reaction is exothermic. In this work, the effect of graphene concentration on the kinetics of Mg hydrogen absorption reaction was investigated. The $MgH_x$-Graphene composites has been prepared by hydrogen induced mechanical alloy (HIMA). The synthesized powder was characterized by XRD and simultaneous TG, DSC analysis. The hydrogenation behaviors were evaluated by using a sievert's type automatic PCT apparatus. In this research, results of kinetic profiles exhibit hydrogen absorption rate of $MgH_x$-5wt.% and 10wt.% graphene composite, as 1.25wt.%/ms, 10.33wt.%/ms against 0.88wt.%/ms for $MgH_x$ alone at 473K.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.1
• /
• pp.202-211
• /
• 1995

Heat and hydrogen transfer characteristics have been experimentally investigated for a hydride reaction bed, in which hydride material LaN $i_{4,7}$A $l_{0.3}$ is contained for hydrogen storage. This problem is of particular interest in the design of metal hydride devices such as metal-hydride refrigerators, heat pumps, or metal-hydride storage units. Transient behavior of hydrogen transfer through the hydride materials as well as heat transfer is studied during absorption and desorption processes in detail. The experimental results obtained indicate that the mass flow of the hydrogen is strongly affected by the governing parameters, such as the initial pressure of the reaction bed, absorption or desorption period, and cooling or heating temperature. These mass transfer results are along with the heat transfer rate between hydride materials and heat transfer medium in the reaction bed.d.d.

• Journal of the Korean Ceramic Society
• /
• v.38 no.10
• /
• pp.867-870
• /
• 2001

The carbon nanomaterials were prepared using the thermal chemical vapor deposition with ${C_2}{H_2}$ on the Ni-graphite mixture as a supported catalyst. The samples were identified by SEM, TEM, Raman spectroscopy, and the hydrogen storage measurement by electrochemical method was also carried out. The purity of carbon nanotube prepared using ground mixture was higher than that of unground one. Also, the amount of hydrogen storage of purified carbon nanomaterials was more than that of unpurified one.

• Transactions of the Korean hydrogen and new energy society
• /
• v.9 no.2
• /
• pp.85-92
• /
• 1998

The hydrogenation behavior of $Mg_2Ni$ powder prepared by ball milling has been studied. Ball milled $Mg_2Ni$ was transformed to an amorphous-like state after 200hr ballmilling, and crystallized to $Mg_2NiH_x$ by hydrogenation at got. The hydrogen storage capacity gradually increased as a function of ball milling time. $Mg_2Ni$ by 400hr ballmilling shows higher hydrogen storage capacity (3H/M) than $Mg_2Ni$ by VIM(Vacuum Induction Melting).

• Transactions of the Korean hydrogen and new energy society
• /
• v.16 no.2
• /
• pp.122-129
• /
• 2005

The characteristics of hydrogen storage have been investigated in the Ti-Cr-Mo and Ti-Cr-V ternary alloys with bcc structure. The alloys were melted by arc furnace and remelted 4-5 times for homogeneity. The lattice parameters, microstructures and phases of the alloys were examined by SEM, EDX and XRD, and the Pressure-Composition isotherms of the alloys were measured. From these data the relationship of the maximum and effective hydrogen storage capacities vs. chemical composition, lattice parameter and the radius of tetrahedral site were analyzed and discussed. The results showed that all of these alloy, in the range of the this study, had mainly bcc solid solutions with small amount of Ti segregation due to a lower melting point of Ti compared with other elements. Lattice parameters of the alloys were very near to the atomic average values of lattice parameters of the constituent elements. It was also found that maximum hydrogen storage capacities of the Ti-Cr-Mo alloys increased with increasing Ti content and the radius of tetrahedral site but the effective hydrogen storage capacities decreased after showing the maximum. The hydrogen storage capacities of the Ti-Cr-V alloys were almost same even though the V contens were quite different from alloy to alloy and this could be attributed to the almost same Ti/Cr ratio of the alloys. The maximum effective hydrogen storage capacity of the Ti-Cr-Mo alloys was revealed at Ti content of about 40${\sim}$50 at% and radius of tetrahedral site of 0.43${\sim}$0.45 nm. The Ti-Cr-V alloys showed the hydrogen storage capacities of 3.0 wt% and effective hydrogen storage capacities of 1.5 wt%.