ABSTRACT
This chapter presents an overview of some of the areas of concern in using computer codes to model fission-product aerosol behavior in the reactor cooling system (RCS) of a water-cooled nuclear reactor during a loss-of-coolant accident. The chapter presents a case study, based on the development at Atomic Energy of Canada Limited (AECL) of a prototype coupled thermalhydraulics/aerosol code package, CATHENA/PACE, to illustrate one approach to building an RCS aerosol behaviour code, and the variation in results that might be expected from different aerosol model assumptions. It begins by outlining the CATHENA/PACE strategy and rationale for the coupled thermalhydraulics/aerosol equations. The numerical methods and strategies in CATHENA/PACE are described briefly and several code calculations based on an S2D test case are presented to illustrate the effects of different model and numerical parameters. In particular, the effect of a simple model for bend deposition is described based on centripetal force.
