This paper presents the experience of the company Ericsson Nikola Tesla (ETK) in the application of VRLA batteries. After a short comment. on conventional lead acid batteries, the paper explains the reasons for introduction of VRLA batteries and presents our experience considering their quality, performance, hydrogen evolution, safety, service life etc. Stress is put on some internal and external factors which affect useful life, such as positive grid corrosion, ambient temperature and charging voltage. ETK also gained experience in relation to adaptation of some UPS systems to VRLA batteries. The article concludes with the list of important advantages and disadvantages of VRLA batteries compared with the flooded ones.

The safety of hydrogen release and discharge from a fuel cell vehicle was evaluated using CFD (Computational Fluid Dynamics) tests in various situations. First, the validity of the locations of the hydrogen sensors installed in Hyundai fuel cell vehicle and the workshop were tested. In addition, the discharge tests of the fuel cell vehicle based on SAE J2578 were conducted in non-ventilated, ventilated and outdoor modes. Through these tests, it was verified that the hydrogen sensor locations are suitable for the detection of hydrogen leakage and SAE J2578 regulation is satisfied in the fuel cell vehicle.

In depth studies of cold neutron sources have been carried out at the Petersburg Nuclear Physics Institute since the early 1970's. The 18 MW WWR-M reactor has been developed to allow a cold source to produce at experimental installation a polarized cold neutron flux of 6x10(8)n/cm(2)s and an ultracold neutron flux of 6x10(3) n/cm(2)s. Experience gained with the WWR-M and other reactors has resulted in a safety strategy. That includes the hazards of operating hydrogen and also provided insight into the reactivity effects of a cold source on the reactor core.

Future energy scenarios envisage a widespread use of hydrogen as energy vector. Installations handling and storing relevant quantities of hydrogen will probably spread around the territory, both in industrial sites and residential areas, arising concerns on the safety aspects. In the present contribution, a novel consequence-based approach is applied to the inherent safety assessment of hydrogen production and distribution system. Alternative scenarios were assessed for the hydrogen system chain from large scale production to final small scale users. Hydrogen transportation and delivery was included in the analysis, introducing a rather innovative aspect for quantitative inherent safety analysis. The inherent safety fingerprint of the system is quantified by a set of Key Performance Indicators (KPIs), which take into account the actual analysis of expected consequences and the safety performance of the equipment. Several case studies were defined to populate the chain systems, considering both commercial technologies and novel alternatives. The KPIs showed the possible safety improvements switching from conventional to alternative technologies as well as critical safety issues that call for their future development.

Hydrogen and oxygen generation due to the radiolysis of water is a recognized hazard in pipe systems used in the nuclear industry, where the accumulation of hydrogen and oxygen at high points in the pipe system is expected, and explosive conditions exist. Pipe ruptures at nuclear facilities were attributed to hydrogen explosions inside pipelines, in nuclear facilities, i.e., Hamaoka, Nuclear Power Station in Japan, and Brunsbuettel in Germany. Prior to these accidents an ignition source for hydrogen was questionable, but these accidents, demonstrated that a mechanism was, in fact, available to initiate combustion and explosion. Hydrogen explosions may occur simultaneously with water hammer accidents in nuclear facilities, and a theoretical mechanism to relate water hammer to hydrogen deflagrations and explosions is presented herein.

Moderator cell of the cold neutron source (CNS) is an important component of China Advanced Research Reactor (CARR). It is a critical problem to keep the void fraction of two-phase hydrogen in the moderator cell to a specified range. Many mockup tests should be carried out for the purpose of the proper design of CARR. However, it is impossible to use hydrogen as test fluid because of the safety and economy consideration, therefore, experiments in order to select a suitable working fluid to study the void fraction were carried out. An annular vessel having the same size with the actual moderator cell was used as test section. Deionized water, alcoholic solution, sucrose solution and sodium chloride solution with different concentrations were used as working fluid to find out the influences of physical properties, such as density, viscosity and surface tension, of two-phase mixture on void fraction. The tests proved that the ratio of surface tension to density of liquid phase has great influence on void fraction, the larger the ratio, the smaller the void fraction. So Freon 113 can be used as working fluid to simulate the void fraction in the two-phase hydrogen thermosiphon loop in the CNS of CARR.

Microbe-based hydrogen production is a potentially cost-effective, non-polluting approach to the production of hydrogen. Research efforts are underway to identify, isolate, and enhance microbial strains which facilitate direct sunlight-to-hydrogen conversion. These efforts are hampered by a lack of adequate instruments to rapidly detect and pinpoint hydrogen producers. There is a need for assays which provide sufficient sensitivity, short response times, scalability, and compatibility with high-throughput methodologies to allow for rapid screening of microbe colonies. GVD Corporation is assisting the National Renewable Energy Laboratory (NREL) in the development of a quick, simple assay that will identify hydrogen producing microbes. This approach could have broader applicability for low-cost hydrogen safety sensors.

Liquid hydrogen is a candidate energy carrier for delivery renewable energy to the public and industry. Unfortunately, the public's first response to the proliferation hydrogen fuel is not associated with hydrogen's environmental benefits but instead focuses on the safety issues and hydrogen's dubious association with the Hindenburg disaster. Before regulations and the market drive hydrogen to the fuel of chose, the safety issues must be systematically addressed and interdisciplinary techniques defined for application. The paper proposes a generic methodology for performing hazards assessments of integrated systems in the hydrogen fuel cycle. The cycle elements include production, stationary storage, transport, and transfer operations. A generic assessment is presented for one such process in the fuel cycle. The assessment approach utilizes the chemical industry standard HAZOP procedure. Standardization of review questions include materials of construction, process control, leak detection, confined space, and ignition sources. Recommended approaches for addressing unanalyzed events is also presented. The Nevada Test Site is developing the capability to safely integrate liquid hydrogen based energy systems using new generation technologies. These technologies must be qualified in a systems approach. The Nevada Test Site's HAZMAT Spill Center has the capability to support testing and verification of liquid hydrogen systems and components which will be needed for deployment of a safe infrastructure.

Helium is commonly used as a tracer gas for leakage measurements across the world. This gas is easy to use without safety issues and enables to measure a very wide magnitude of leakage rates with well proven detectors (Mass Spectrometers). Nevertheless, shortage and price increase of helium in several world areas, encourage industry users to look for alternative tracing gases for leakage measurement. The Valve Commission of CETIM has decided to investigate the use of two alternative tracer gas mixtures in the field of packing fugitive emissions testing according to ISO 15848-1. This standard allows the use of Helium and Methane as tracer gases. The leakage measurements based on Hydrogen tracer gas has been developed in the recent years, with the use of Hydrogen (5%2-Nitrogen (95%2 mixture for safety concerns. The test programme involves comparative fugitive emission measurements on graphite packing, following ISO 15848-1 test procedure with Helium, Hydrogen (5%2Nitrogen (95%2 and Methane (10%2-Nitrogen (90%2 mix tracer gases. Several measuring methods are investigated as sniffing, accumulation, flushing and global vacuum using the relevant detectors for the different gases and measurement methods. Whereas the measurements did not appear to be sensitive enough with the Methane (10%2-Nitrogen (90%2 for some measurements methods, the Hydrogen (5%2-Nitrogen (95%2 mixture has shown a good potential for fugitive emission measurements according to ISO 15848-1.

Safety is of paramount importance in the design of hydrogen-powered vehicles. Inherent safety is an important design consideration in modern engineering safety practice. Through inherent safety, systems are designed to be safe without extensive protective systems. Quantified risk assessment can play a valuable role in optimizing the safety features of the on-board hydrogen system. Protective safety systems can sometimes fail to function and quantification can help to indicate where redundant systems may be required as well as how often they must be functionally checked. The size of flammable zones from some types of open air leaks can provide guidance for the design of vehicle systems.