Hydrogen generated from clean and renewable energy sources has been considered as an alternate fuel to carbon based fossil fuels for several decades. Although many advances in hydrogen production and usage have been made, storing hydrogen remains a significant challenge. Many drawbacks including energy intensive processes, low volumetric densities, and safety concerns are associated with storing hydrogen as pressured or liquefied. Solid state hydrogen storage is considered to be the most promising method as a safe and effective storage option, but there is still no material or method that satisfies the requirements for a practical approach. A feasible hydrogen storage media should address several issues including targeted storage capacities, thermodynamics and hydrogen sorption kinetics, and safety. Nanostructured materials can provide tailor-made properties for storing and releasing hydrogen to fulfill, at least, the partial requirements. This short review, not a comprehensive review of all the materials or technologies in hydrogen storage, summarizes some of the recent developments in application of nanostructures for solid state hydrogen storage; particular attention has been devoted to the most recent development of nanocomposites with tuned dehydrogenation temperatures and kinetics through the control of pore size and surface chemistry.

This work sought to evaluate the explosion severity on hydrogen enrichment in methane-air mixture explosion. For this purpose, different hydrogen mixture compositions ranges between 4 to 8%2v/v were considered. This work was performed using CFD tool FLACS that has been well validated for safety studies on both natural gas/methane and hydrogen system. FLACS is used to validate the maximum pressure and flame speed predicted by the CFD tool for combustion of premixed mixtures of methane and hydrogen against the experimental data. Experimental work was carried out in a closed pipe containing 90-degree bends with a volume of 0.41 m(3), operating at ambient conditions. From the experiment observation, it shown that the coupling effect of bending and thermal diffusivity gave the dramatic influent on explosion severity in hydrogen-methane/air at very lean concentration. However, simulation results showed that FLACs is under-predicting the overpressure at very lean concentration of hydrogen in methane/air mixtures. It can be said that lower hydrogen content in methane/air mixture limits the hydrogen diffusivity, leading to the decrease of the burning rate and flame speeds. It is also demonstrated that the presence of 90-degree bend in closed pipe system increases the simulated flame speeds to the factor of 2-3, as compared to the experimental data. There are significant discrepancies between experimental and simulation, however, the results seem conservative in general.

The work described here concerns the development of fibre sensors and networks for monitoring trace gases such as methane, acetylene, carbon dioxide, carbon monoxide and hydrogen sulphide, all of which are important in environmental or safety monitoring. A 45-point fibre sensor network using a single DFB laser source has been installed on a landfill site to assess the distribution of methane generation across the site, with detection levels from

Thermal oxidation of silicon is an important process step in MEMS device fabrication. Thicker oxide layers are often used as structural components and can take days or weeks to grow, causing high gas costs, maintenance issues, and a process bottleneck. Pyrolytic steam, which is generated from hydrogen and oxygen combustion, was the default process, but has serious drawbacks: cost, safety, particles, permitting, reduced growth rate, rapid hydrogen consumption, component breakdown and limited steam flow rates. Results from data collected over a 24 month period by a MEMS manufacturer supports replacement of pyrolytic torches with RASIRC Steamer technology to reduce process cycle time and enable expansion previously limited by local hydrogen permitting. Data was gathered to determine whether Steamers can meet or exceed pyrolytic torch performance. The RASIRC Steamer uses de-ionized water as its steam source, eliminating dependence on hydrogen and oxygen. A non-porous hydrophilic membrane selectively allows water vapor to pass. All other molecules are greatly restricted, so contaminants in water such as dissolved gases, ions, total organic compounds (TOC), particles, and metals can be removed in the steam phase. The MEMS manufacturer improved growth rate by 7%2over the growth range from 1 mu m to 3.5 mu m. Over a four month period, wafer uniformity, refractive index, wafer stress, and etch rate were tracked with no significant difference found. The elimination of hydrogen generated a four-month return on investment (ROI). Mean time between failure (MTBF) was increased from 3 weeks to 32 weeks based on three Steamers operating over eight months.

As one of the main experimental facilities in the Japan Proton Accelerator Research Complex (J-PARC), an intense spallation neutron source (JSNS) driven by a 1 MW proton beam is being constructed. Cryogenic hydrogen at supercritical pressure is selected as a moderator. The total nuclear heating at the moderators is estimated to be a 3.7 kW. A hydrogen system to cool the moderators has been designed. The most severe off-normal event for the cryogenic hydrogen system is considered to be a hydrogen leak when a pipe cracks. In such a case, the hydrogen must be discharged to atmosphere quickly and safely. An analytical code that simulates the pressure change during a hydrogen leak was developed. A pressure rise analysis for various sized cracks was performed, and the required sizes for relief devices were determined. A safety valve size is phi 42.7 mm and a rupture disc for vacuum layer should have a diameter of 37.1 mm, respectively.

In order to establish a D-T fusion reactor as an energy source, it is not enough to have a DT burning plasma, and economical conversion of fusion energy to electricity and/or heat, a large enough margin of tritium breeding and tritium safety must be simultaneously achieved. In particular, handling of huge amount of tritium needs significant efforts to ensure that the radiation dose of radiological workers and of the public is below the limits specified by the International Commission on Radiological Protection (ICRP). In this paper, after the introduction of tritium as a fuel of DT reactors and as a radioisotope of hydrogen, tritium safety issues in fuel cycle and blanket systems are summarized. In particular, in-vessel tritium inventory, the most important and uncertain tritium safety issue, is discussed in detail.

The effect of hydrogenation on structure and properties of TC21 alloy by die forming and sintering using hydrogenated powder was researched by means of the room-temperature die forming and sintering in protection air to produce titanium alloy. The results show that the structure of TC21 titanium sintered body using hydrogenated powder with hydrogen content of 0.39 wt%2by die forming and sintering is thinner and the density is higher than the others. The compression strength and compressive yield strength of TC21 sintered body with hydrogen content of 0.39 wt%2are well. With hydrogen content increasing, the structure of TC21 production using hydrogenated powder by die forming and sintering gets well and the grain size becomes smaller. After annealing, the structure of TC21 titanium production gets more uniformity and refinement obviously, and the hydrogen content of TC21 alloy safety state is achieved. In the end, the density and mechanical property of TC21 titanium alloy sintered body with hydrogen content of 0.39wt%2is the best.

The influence of hydrogenation on structure and properties of TC4 alloy by die forming and sintering using hydrogenated powder was researched and the modification mechanism was analyzed by means of the room-temperature die forming and sintering in protection air to produce titanium alloy. The results show that, with the increase of hydrogen content and sintering temperature, the structure of TC4 titanium production using hydrogenated powder by die forming and sintering was changed from Widmanstaten structure to duplex structure. The density of TC4 titanium production shows a rise trend gradually. After annealing, the structure of TC4 titanium production gets more uniformity and refinement obviously, the compress yield limit shows a rising trend gradually, and the hydrogen content of TC4 alloy safety state is achieved. The density and mechanical property of TC4 titanium alloy with hydrogen content of 0.42wt%2is the best.

GASFLOW-II is a finite-volume computer code that solves the time-dependent compressible Navier-Stokes equations for multiple gas species in a dispersed liquid water two-phase medium, The fluid-dynamics algorithm is coupled to the chemical kinetics of combusting gases to simulate diffusion or propagating flames in complex geometries of nuclear containments. GASFLOW-II is therefore able to predict gaseous distributions and thermal and pressure loads on containment structures and safety related equipment in the event combustion occurs. Current developments of GASFLOW-II are focused on hydrogen distribution, mitigation measures including carbon dioxide inerting, and possible combustion events in nuclear reactor containments. Fluid turbulence is calculated to enhance the transport and mixing of gases in rooms and volumes that may be connected by a ventilation system. Condensation, vaporization, and heat transfer to walls, floors, ceilings, internal structures, and within the fluid are calculated to model the appropriate mass and energy sinks.

Two years ago Telecom Italia has started a program to test fuel cell based systems as an alternative to batteries and gensets for the backup power requirements of the telecommunications industry. Fuel cell technology looks very promising for this application and several solutions are being proposed by various manufacturers, so Telecom Italia is continuing the program, testing different systems in order to evaluate their real performances and to determine parameters and requirements for a future standardization. All tests are performed in strict collaboration with the system's manufacturer and their results are shared and jointly evaluated. This paper deals with the tests performed on the ElectraGen (TM) system, manufactured by IdaTech and distributed in Italy by RENCO SpA. This system, expressly designed to provide stand-by power for critical power applications, uses a combination of a Proton Exchange Membrane (PEM) fuel cell and energy storage devices (batteries or ultracapacitors) to provide uninterrupted backup power to an existing -48 Volt DC power system. The system operates as a stand-by service and continuously monitors existing DC bus voltage. It can be configured both to respond instantly to voltage drops or for a delayed response to minimize fuel consumption when coupled with existing battery systems. The system is fueled by commercial grade (99.95%2dry) hydrogen, supplied in standard hi pressure bottles or produced by a fuel processor via steam reforming of a water/methanol mixture. The fuel reformer guarantees extended run times with a very compact fuel source. All the safety issues resulting from the transport and storage of hi-pressure hydrogen are overridden. As in a previous paper on this matter, the joint-authorship approach provides unique perspectives from both the manufacturer, IdaTech, and the end-user, Telecom Italia Spa, across the phases of the Held trials