In case of a severe accident in light water reactors (LWR) a high amount of hydrogen, up to about 20 000 m(n)(3), might be generated and released into the containment. The mixture, consisting of hydrogen and oxygen, may either burn or detonate, if ignited. In case of detonation the generated shock wave may endanger the integrity of the containment or safety-related systems. Consequently, an effective removal of hydrogen is required. Hydrogen and oxygen react exothermally at catalytically acting surfaces, already at room temperature, and this is used in catalytic recombiners. It is recommended to combine recombiners with spark or catalytic igniters, in order to cover a broader spectrum of accident sequences. In this contribution, state of the art of hydrogen removal devices are reviewed and the possibilities for innovative methods, making use of the phenomena arising in the containments, using further components will be illustrated accordingly. (C) 2000 Elsevier Science S.A. All rights reserved.

In a near future, with an increasing use of hydrogen as an energy vector, gaseous hydrogen transport as well as high capacity storage may imply the use of high strength steel pipelines for economical reasons. However, such materials are well known to be sensitive to hydrogen embrittlement (HE). For safety reasons, it is thus necessary to improve and clarify the means of quantifying embrittlement. The present paper exposes the changes in mechanical properties of a grade API X80 steel through numerous mechanical tests, i.e. tensile tests, disk pressure test, fracture toughness and fatigue crack growth measurements, WOL tests, performed either in neutral atmosphere or in high-pressure of hydrogen gas. The observed results are then discussed in front of safety considerations for the redaction of standards for the qualification of materials dedicating to hydrogen transport. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

By limiting the pipes thickness necessary to sustain high pressure, high-strength steels could prove economically relevant for transmitting large gas quantities in pipelines on long distance. Up to now, the existing hydrogen pipelines have used lower-strength steels to avoid any hydrogen embrittlement. The CATHY-GDF project, funded by the French National Agency for Research, explored the ability of an industrial X80 grade for the transmission of pressurized hydrogen gas in large diameter pipelines. This project has developed experimental facilities to test the material under hydrogen gas pressure. Indeed, tensile, toughness, crack propagation and disc rupture tests have been performed. From these results, the effect of hydrogen pressure on the size of some critical defects has been analyzed allowing proposing some recommendations on the design of X80 pipe for hydrogen transport. Cost of Hydrogen transport could be several times higher than natural gas one for a given energy amount. Moreover, building hydrogen pipeline using high grade steels could induce a 10 to 40%2cost benefit instead of using low grade steels, despite their lower hydrogen susceptibility. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

The application of combinational chemistry has been changing since it was first described almost two decades ago. This review highlights relevant innovative ideas using the combinatorial chemistry approach, fodusing on the present and future scope of this technology and its general acceptance among the scientific community. Recent developments include solid-supported reagents, catalysts, scavengers and purification, resin technology (polymer-supported chemistry on monolithic disks); reporter resins for solid-phase organic chemistry; dynamic combinational libraries; natural product-based libraries and chemical genetics; and microreactors.

Liquid hydrogen at 20 K was harmlessly released at Turin's Porta Susa station over a period of seven hours on 9 July 1991 through the safety valve of a dewar-type tank on a railway wagon following the loss of the vacuum between its two walls. Commercially available programs were unable to model this type of release in the unusual conditions in which this hydrogen had been stored. A model illustrating the course of the accident was therefore worked out. A start was made by examining the changes in the physical and thermodynamic properties of the hydrogen progress in the dewar to find out how long it had taken to build up the pressure needed to open the safety valve. Owing to the complex geometry of the insulating layer in the interspace of the dewar on which the liquefaction of the air took place, the heat exchange coefficient could not be determined a priori. It was therefore assumed and subsequently quantified by means of an iterative process. The thermodynamic data were then used to examine the outflow of the hydrogen from the venting line. Flow dynamic calculations showed that the hydrogen was entirely lost through the safety valve and that pressure losses along the approx. 3-m line were negligible. The model also showed that the speed of the outflow was subsonic. The speed evaluated will enable the dispersion of the hydrogen and hence the areas at risk to be evaluated in the subsequent stages of the study. (c) 2005 Elsevier Ltd. All rights reserved.

The use of hydrocarbon-hydrogen mixtures has been proven to be a valuable system for emission reduction and flame stabilisation. For the assessment of process hazards and the safe design of process equipment handling ethanol-hydrogen, the knowledge of safety parameters, such as maximum pressure, maximum rate of pressure rise and burning velocity, is required. In this work, the explosion behaviour of pure ethanol and ethanol-hydrogen/air mixtures is studied for different initial temperature and equivalence ratio. Experimental tests are carried out in a 5 dm(3) closed cylindrical vessel.