ANALYSES OF HYDROGEN DISPERSION - GASFLOW COMPUTER-PROGRAM FOR DETERMINATION OF HYDROGEN DISTRIBUTION IN PRESSURIZED-WATER REACTORS

A contract about cooperation in research among the Karlsruhe Research Center (FZK), Siemens, and the German operators has been concluded wit hin the conceptual design development of the European Pressurized Wate r Reactor (EPR) as early as in 1993. This cooperation serves to study and manage accident phenomena exceeding the design basis. consequently , these activities not only contribute to finding conceptual designs f or future plants, but also add to the safety of operation of current n uclear power plants. One key research area within this cooperation is the demonstration, on the basis off thorough scientific research, of h ydrogen management in accident scenarios. Activities in this field foc us not only on experimental proof, but also on the further development and application of the multidimensional finite difference computation program called Gasflow. The program allows integral analysis to be ca rried out of hydrogen transport and the way in which hydrogen mixes in the atmosphere within the containment. In addition, countermeasures c an be modeled, such as the use of recombiners and igniters for hydroge n removal. The suitability of Gasflow has been demonstrated by means o f validation calculations of integral tests in the Superheated Steam R eactor (HDR) and in the Battelle model containment.