The experimental investigation of a prototypical set‐up simulating a loss of flow accident
in a helium‐cooled breeding blanket first wall mock‐up under typical heat load conditions is presented.
The experimental campaign reproduces the expected DEMO thermal‐hydraulics conditions
during normal and off‐normal situations and aims at providing some insight into the fast transients
associated with the loss of flow in the blanket first wall. The experimental set‐up and the definition
of the experimental matrix are discussed, including pre‐test analysis performed in support of these
activities. The major experimental results are discussed, and a procedure of using the acquired data
for validating and calibrating the RELAP‐3D model of the mock‐up is introduced. All these activities
contributed to the creation of a relevant theoretical and practical experience that can be used in
further studies concerning incidental transients in real‐plant scenarios in the framework of DEMO
plant fusion safety activities
