The prediction of 2D thermal detonations and resulting damage potential

The main purpose of this paper is to introduce a new concept for the processes responsible for the escalation and propagation of steam explosions. The concept recognizes that initially only a small quantity of coolant around each coarsely premixed melt mass ''sees'' the fragmenting debris coming off it, hence it is called the concept of ''microinteractions''. We also derive the analytical basis for it, define the nature of the requisite constitutive laws and related experimental data, and demonstrate that this concept is essential for the prediction of steam explosion energetics in large-scale premixtures in 2D geometries. We also provide the first numerical illustrations of this concept, implemented in the computer code ESPROSE.m. Further, we provide the first numerical results of steam explosions in large water pools, i.e. ex-vessel explosions. These results reveal two important mechanisms for explosion ''venting'' and thus for reducing the dynamic loads on adjacent structures. We conclude that, taken together, the ''microinteractions'' and ''venting'' make realistic predictions of steam explosion loads feasible and within reach in the near future. (orig.)