Development of an Integral Model of a Radioactive Jet Released Accidentally from a Nuclear Reactor

Summary

This paper concerns the theoretical study of a hot jet with internal heat generation issued vertically into a horizontal cross-flow. The study focuses on the initial region of the jet, where the initial momentum and buoyancy of the jet are still influent. The main objective of this study is to predict the height reached by the jet in order to give initial conditions to large scale polluant transport models. The model MICAR developed by CEA is based upon an integral formulation: The conservation equations are integrated in a cross-section through the jet. It requires an empirical model for the mass flow of the entrained fluid.

Parametric studies are done with the model. Attention is focused on the trajectoreis and on the dilution of a polluant contained in the emission. External parameters which have been covered are :

• Internal heat generation,

• Ratio of wind velocity to jet velocity,

• Ambient stratification.