Status Report on H2-DDT Model and Criteria Verification: Stage of CFD Tools for H2-DDT Model and Criteria Verification versus Validation - With Some Illustrating Examples

[Automatically extracted and translated] The assessment of the integrity of containments under severe accident conditions is an important safety issue for technical systems. In case of severe accidents in water-cooled nuclear reactors, significant quantities of hydrogen and steam could be released into the atmosphere of the containment, reaching flammability or even detonability limits. To control accidental hydrogen combustion, different safety measures have been developed as part of the defense-in-depth concept, including additional accident management strategies. The objective of the research is to develop a common safety approach to protect the worker, the population, and the environment from any damage that could result from the use of nuclear energy. Within the scope of the EC research on severe accidents, models and criteria for prediction of deflagration-to-detonation transition (DDT) in hydrogen-air-steam systems are being developed, based on the project specification. The working task of the FZJ is addressed to model and criteria verification. During the time period under review from January to June 1997, the research team in the ISRI of the FZ-Jülich has made progress in scientific/technical computing for safety research activities, towards achieving computational fluid dynamic tools (CFD) using vector/parallel processing capabilities.