Two aspects of hydrogen risk

The hydrogen risk in nuclear reactors is an extensive problem which includes several aspects i.e.: the prediction of the total amount of hydrogen release, its mixing with air and possibility of overconcentration in parts of the containment, burning via deflagrations or detonations, mitigation, containment integrity etc. An extensive amount of work has already been devoted to this problem. The scope of this paper is to present two subjects related to hydrogen risk in PWR containments which are in progress at CEA.DEMT and which to the authors knowledge have been unsufficiently investigated up to now. The first is the possibility of stratification of hydrogen in a large volume when injected from the bottom. The related experimental work is described in section II. The second is the computation of detonation shock waves in confined or semi-confined volumes (section III) and the resulting impulsive load on the containments