Two main meetings were organized in this WP7 “Containment” in the past six months. One took place in Garching (Germany), hosted by GRS on June 28-29, 2010. Four workshops were devoted to benchmarks that started at the end of 2009 on the following subjects: containment sprays, hydrogen combustion, steam condensation, and generic containment benchmark. The other meeting, hosted by IVS in Bratislava (Slovakia) on July 8th 2010, was devoted to the topic of ex-vessel fuel-coolant interaction.
Modelling of containment sprays
The first phase of this benchmark ended. The exercise consisted in simulating an elementary heat and mass transfer experiment: separate uniform droplets were generated and observed in a vessel with a controlled atmosphere. For this exercise, both Lumped-Parameter (LP) and Computational Fluid Dynamics codes (CFD) were used. The following organizations presented their results: IRSN (organizer) and EDF (France), GRS and KIT (Germany), UJV (Czech Republic), UJD SR (Slovak Republic), NRG (The Netherlands), UNIPI and RSE (Italy), and LEI (Lithuania).
Modelling of hydrogen combustion
A significant milestone was reached on this benchmark on hydrogen combustion (flame acceleration and deflagration to detonation transition). The benchmark consists in simulating experiments on hydrogen combustion performed in the ENACCEF facility in CNRS/Orléans (France). The following organizations presented their results: IRSN (organizer), AREVA NP GmbH (Germany), GRS, RUB, NUBIKI (Hungary), KAERI (Korea) and LEI.
Modelling of steam condensation
The meeting in Garching was also an opportunity to compare results of the steam condensation benchmark that started in January 2010. Experiments that were performed in the CONAN facility (University of Pisa) were simulated with CFD codes. The results of following organizations were compared at the workshop: UNIPI (organizer), CEA (France), FZ Jülich (Germany), KIT, JSI (Slovenia), NUBIKI, UJV, and AECL (Canada). The next step will be the comparison of simulations and experiments with lower flow velocities.
Development of a generic containment model
In Garching, first results of the benchmark that started in January 2010 were presented and discussed. The purpose is to compare code results by simulating a transient in a precise and single containment model, based on the containment of a German nuclear power plant. The following organizations presented their results (all calculated with LP codes): FZ Jülich (organizer), AREVA NP GmbH, GRS, RUB, NUBIKI, UJV, UNIPI, ERSE, NRG, IRSN, ENEA (Italy), TUS (Bulgaria), JSI, and VTT (Finland). The next step has been the submission of revised calculations in October 2010. Apart from that, KIT proposed a new generic containment geometry for use in a similar exercise with CFD codes.
Ex-vessel fuel-coolant interaction
At the meeting in Bratislava, the role of the void in explosions was discussed further, and a report will be issued soon. Another topic of discussion was the analysis and pre-calculations of the planned fuel-coolant interaction test on the DISCO facility at KIT within the LACOMECO FP7 project. Finally, calculations of a debris bed formation experiment (probably the DEFOR experiment at KTH in Stockholm), to be carried out together with members of the SARNET WP5 Corium and Debris Coolability, were also discussed.

Contact: Ivo Kljenak, ivo.kljenak@ijs.si