Accumulator hydrogen generation

The hydrogen generation and the decomposition of water (as an essential part of the electrolyte) during charging periods shall be considered in more detail under lead-acid accumulators. 

The Zone 2A canyon eievator pit and Room 109 are the only two areas in the HCF where waste will be accumulated. By the time that the waste is moved into Room 109, the hydrogen generation rate is sufficiently low as to preclude accumulation to flammable levels (Mitchell and Naegeli 1999). The normal Zone 2A ventilation flow of 1800 cfm (which Includes flow into the SCB s) will preclude any appreciable hydrogen concentrations in Room 109 or the Zone 2A canyon. 

Since no charge can accumulate on any metal surface, the electrons generated by the anodic reaction must aD be used up by the cathodic reaction. This can only occur in Fig. 1 where the anodic and cathodic reaction Unes cross. At this point, the rate of the anodic reaction, the corrosion rate, equtds the rate of the cathodic reaction—in this case, hydrogen generation. This rate is called the open-circuit corrosion rate, abbreviated The potential at which the lines cross is called the open-circuit corrosion potential, abbreviated This type of plot is called an Evans... 

Explosions and fire may arise from electrical shorting, leaking fuel pipes, dust accumulation (spontaneous combustion) and from hydrogen generation during battery charging. The truck itself can be the source of ignition if operated in flammable atmospheres... 

The above discussion has assumed that the crack is loaded in mode 1 (the crack opening mode, with a tensile stress normal to the plane of the crack). Hydrogen has relatively little effect in modes II or III, as these generate shear stresses at the crack tip, rather than tensile stresses, and the shear behaviour of steels is relatively little affected by hydrogen, presumably because dilation of the lattice at the crack tip (which does not occur in modes II and III) is required for hydrogen accumulation. 

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