Description of the production program, ensuing requirements on the batch annealing plant and measures designed to ensure their fulfillment. Survey of annealing product and furnace chamber dimensions, installed loads and annealing temperatures. Makeup of the annealing stacks and temperature measurements under the hood. Variation in time of circulating gas temperature, determination of the core temperature, precalculation of the annealing time. Change-over to annealing under hydrogen: advantages ensured by the use of hydrogen, protective gas safety system, economic efficiency considerations.

An accidental hydrogen release within an equipment enclosure may result in the presence of detonable mixture in a confined environment. From a safety standpoint, it is then useful to assess the potential for damage. In that context, numerical simulation of the sequence of events subsequent to detonative ignition provides a useful tool, although with obvious limitations. This article describes the procedure, summarizes two case studies, and reviews the limitations. First, a hydrogen dispersion pattern is obtained from numerical simulation of dispersion, using a commercial package designed primarily for incompressible flow. This dispersion cloud is then used as the initial condition in an inviscid, compressible, reactive flow simulation. To force detonative ignition, a sufficiently large amount of energy is deposited in a small region that corresponds to the ignition location. Chemistry is modeled using a single step Arrhenius model. Because the wave thickness is small compared with the computational domain, a fine mesh is needed, limiting the practicality of the process to two-dimensional geometries. This is the most significant limitation; it is conservative. The two cases described in the paper include an electrolyzer, in which a small release occurs, leading potentially to some damage to the enclosure, and a reformer, in which the consequences are potentially more serious. (C) 2007 Elsevier Ltd. All rights reserved.

This paper presents a concept for an implantable micro-pump based on hydrogen-generating gas cells. The gas-generating cell is separated from the drug reservoir by an expandable latex membrane. The system offers linear drug delivery with flowrates ranging from 8 nl/s to 2 mu l/s and a total delivery volume of up to 160 ml. Drugs can be dispensed over a wide backpressure range. The device is scalable based on the size of the gas-producing cell and requires no external energy source. Possible fields of application include in vivo local drug delivery for chemotherapy, diabetes, and pain management.

The residential sector accounts for about a third of the total world energy consumption. Energy efficiency, Renewable Energy Sources and Hydrogen can play an important role in reducing the consumptions and the emissions and improving the energy security if integrated (Efficiency, Res, Hydrogen) systems are developed and experimented. The paper analyzes a real residential 100 square meters house, where energy efficiency measures and RES technologies have been applied, sizing a hydrogen system (electrolyzer, metal hydrides and fuel cell) for power backup, taking into consideration its dynamic behavior, experimentally determined. The technologies used are already available in the market and, except hydrogen technologies, sufficiently mature. Through energy efficiency technologies (insulation, absorbers, etc), the maximum electrical and thermal power needed decreases from 4.4 kW(e) to 1.7 kW(e) (annual consumption from 5000 kWh to 1200 kWh) and from 5.2 kW, to 1.6 kW(t) (annual consumption from 14,600 kWh to 4500 kWh) respectively. With these reduced values it has been possible to supply the consumptions entirely by small photovoltaic and solar thermal plants (less than 10 m(2) each). The hydrogen backup even if remains the most expensive (versus traditional batteries and gasoline generator), satisfying all the electric needs for one day, increases the security and allows net metering. Moreover the low-pressure hydrogen storage system through metal hydrides guarantees system safety too. Finally the system modularity can also satisfy higher energy production. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

The research programs at the CEA in the field of safety in nuclear reactors are carried out in a framework of international partnerships. Their purpose is to develop studies on: - The methods allowing for the determination of earthquake hazards and their consequences; - The behaviour of fuel in an accident situation; - The comprehension of deflagration and detonation phenomena of hydrogen and the search for effective prevention methods involving an explosion risk; - The cooling of corium in order to stop its progression in and outside the vessel thereby reducing the risk of perforating the basemat; - The behaviour of the different fission product families according to their volatility for the UO2 and MOX fuels. (C) 2012 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Cryogenic leak detection is critical to space missions, particularly for avoiding launch delays. The real-time, multi-location, early leak detection of oxygen and hydrogen down to ppm levels is extremely important for safety, reliability, and economic reasons. One of the significant challenges in meeting these requirements has been the drift effect that is caused by the exposure to extreme temperatures. This paper discusses the effect of the development of a sensor supporting matrix to improve the overall behavior of oxygen and hydrogen optical sensors at cryogenic temperatures. These achievements offer great advances in the fiber optic leak detection of cryogenic oxygen and hydrogen, specifically for space applications. Emphasis on operational conditions such as -150 K and vacuum environments, in addition to performance characteristics such as sensitivity (10 ppm) and response time (similar to 3 sec), are addressed in this paper.

The present paper deals with specific safety issues resulting from the coupling of a nuclear reactor (very high temperature reactor, VHTR) with a hydrogen production plant (HYPP). The first part is devoted to the safety approach consisting in taking into account the safety standards and rules dedicated to the nuclear facility as well as those dedicated to the process industry. This approach enabled two main families of events to be distinguished: the so-called internal events taking place in the coupling circuit (transients, breaks in pipes and in heat exchangers) and the external events able to threat the integrity of the various equipments (in particular the VHTR containment and emergency cooling system) that could result from accidents in the HYPP. By considering a hydrogen production by means of the iodine/sulfur (IS) process, the consequences of the both families of events aforementioned have been assessed in order to provide an order of magnitude of the effects of the incidents and accidents and also in order to propose safety provisions to mitigate these effects when it is necessary. The study of transients induced by a failure of a part of the HYPP has shown the possibility to keep the part of the HYPP unaffected by the transient under operation by means of an adapted regulation set. Moreover, the time to react in case of transfer of corrosive products in the VHTR containment has been assessed as well as the thermohydraulic loading that would experience the coupling pipes in case of very fast uncoupling of the facilities aiming at avoiding an excessive pressurization of the VHTR containment. Regarding the external events, by applying a method used in the process industries, the bounding representative scenarios have been identified on the basis of their consequences but also on the basis of their occurrence frequency. The consequences of the selected bounding scenarios, calculated taking into the source-term, the atmospheric dispersion and the pressure and toxic effects induced respectively by a hydrogen unconfined vapour cloud explosion (UVCE) and a sulfur dioxide release have been assessed. The resulting safety distance of about 100 m for the UVCE is fairly acceptable in terms of performance (head loss and thermal loss) of the coupling system. However, the longer safety distance (about 1.5 km) calculated for a SO(2) release implies to foresee a long distance to settle the control room of the site or to foresee provisions able to stop very fast the SO(2) leak. (C) 2011 Elsevier B.V. All rights reserved.

A gas recycling system to prevent losses of isotopically enriched hydrogen gas has been developed for the operation of a liquid target (2.7 1) used by the Radiative Muon Capture group at TRIUMF. The experimental requirements for high gas purity (chemical impurities below 10(-9)), low operating pressure (below 1 bar abs) and high loading pressure (about 10 bar needed for a palladium purifier) together with the usual hydrogen safety requirements were satisfied with a metal hydride storage device in combination with a small pump/compressor system. A description of the complete system together with its characteristic operational data are given in this paper.

The article summarises results of quantitative risk assessment for the operation of six large gasholders in the area of great industrial agglomeration in the Czech Republic. Gasholders for storing combustion gases contain significant amounts of dangerous substances, especially of carbon monoxide and hydrogen. That is why safety reports on these gasholders were prepared in the framework of implementation of the SEVESO 11 Directive. Although gasholders have gradually been shut down in the world, they still bring the heavy industry in the area of the city of Ostrava a considerable financial saving. Chosen industrial plants actually combust cheap waste gases, i.e. coking, converter and blast-furnace gases instead of natural gas. As a consequence, the gasholders are not expected to be closed in the near future either. With regard to the age (the oldest gasholder is more than 60 years old) and a high population density in the area concerned, it was necessary to do a detailed risk analysis. Many methods, from simple screening and indexing methods (Selection Method from Purple Book CPR 18E. IAEA-TECDOC-727 method, method based on the Dow's Fire and Explosion Index), through the systematic HAZOP method, modelling of the dispersion of toxic gas releases up to the determination of risk probability and societal acceptability were employed for the assessment of risks of the gasholders. The goal of the article is to present results of the assessment of risks connected with the operation of the large gasholders, to furnish information about possible operational problems and to verify the applicability of recognised methods of risk analysis for these specific serious sources of risks. (C) 2004 Elsevier Ltd. All rights reserved.