Simulation of containment thermal-hydraulics in the Marviken Blowdown 16 experiment with ASTEC and CONTAIN codes

The boiling heavy water reactor Blowdown 16 experiment, which was performed in the Marviken experimental facility, was simulated with the ASTEC and CONTAIN codes. The main purpose of the work was the assessment of the codes for simulating thermal-hydraulic phenomena in a BWR containment at accident conditions. Simulated pressures, atmosphere temperatures and wetwell pool masses are compared to experimental measurements. The results show that both codes satisfactorily reproduced the overall containment thermal-hydraulic behaviour. The simulations also allow a more detailed understanding of the governing mechanisms during the performed experiment.