Quantity and Nature of LWR Aerosols Produced in the Pressure Vessel during Core Heatup Accidents - A Chemical Equilibrium Estimate.

摘要

The degree of vaporization of LWR core materials was estimated using a highly idealized procedure involving (1) specification of the phases that are present for both structural and fuel material; (2) estimation of the vapor pressures exerted by the individual components of each phase; and (3) assuming a degree of vaporization of each phase constituent, to allow equilibration between gaseous and condensed species within the assumed pressure vessel volume. The degree of vaporization of many core materials is limited by other complex factors such as local mass transport conditions and solid-phase diffusion rates; however, the results obtained in this study serve to illustrate the types of driving forces for vaporization that are present and to give some indication of the composition of the vaporized material. In addition to estimated degrees of vaporization, information is included regarding the projected chemical forms of the condensed material for the expected range of oxygen potentials in the reactor vessel.