Detailed assessment of the Heiss Dampf Reaktor hydrogen deflagration experiments E12

The contribution by the Heiss Dampf Reaktor Safety Program, phase III, to t he German containment hydrogen research activities were two fold: 1. to confirm the findings of the experiments in the Battelle Model Contain ment (BMC) in volumes of typically similar to 100 m(3) by similar ones at a larger scale with a total volume of 500 m(3) 2. to broaden the database for assessing the emerging modeling strategy for larger scales toward more realistic subcompartment sizes. To supplement the results obtained in the BMC in a propel; controlled manne r for additional model development and computer code verification a total o f;seven experiments was performed, and the following positions for hydrogen ignition were examined: test group E12.1: hydrogen deflagration in a vertically oriented subcompart ment test group E12.2: ignition close to the vent test group E12.3: accelerated jet ignition in a horizontal direction. The maximum peak pressure occurred for E12.3.3 at 1.8 bars under typical ac celerated jet ignition conditions far 12 vol% initial H-2 concentration. Be cause of larger vent openings, maximum peak pressures were generally lower than observed in BMC tests, whereas maximum temperatures were substantially higher reaching 1000 degrees C and above. A few comparisons between data a nd code results from CONTAIN, RALOC-HYDCOM, and CONTAIN/BASSIM computations are shown, indicating the need for further improvements.