The code RENONS for the prediction of nonvolatile species release from liquid surfaces into a gas

Abstract

In the field of nuclear safety, the release of volatile and nonvolatile species from liquid surfaces into a gas atmosphere is important for aerosol source term considerations. In case of a hypothetical fast breeder reactor accident with tank failure, primary coolant sodium with suspended or solved fuel particles and fission products may be released into the containment. The code package REVOLS/RENONS calculates, based on theoretical mechanistic models, the release of these species from the pool surface into the inert gas atmosphere of the inner containment. Hereby, the module REVOLS calculates the RElease of VOlatile Species (Koch et al., 1991). Whereas the evaporative release of the volatile species is governed by diffusive and convective transport processes, the release of the nonvolatile may be governed by mechanic processes entraining droplets from the wavy surface under conditions of convection in the atmosphere. The modular structured code RENONS (RElease of NONvolatile Species) calculates the liquid entrainment rate of nonvolatile species from pool surfaces by a parallel gas flow. Hence, the influence of the system temperatures, the pool inventory and the geometry as well as the decisive influence of the thermal hydraulic conditions on the entrainment rate can be investigated.