Large-scale experiments show that whenever a loss of coolant accident occurs water pools are generated. Stratification of steam-saturated gas develops above growing water pools causing a different thermal hydraulics in the subcompartment where the water pool is located. Hereafter, the LWR Aerosols Containment Experiment (LACE) LA4 experiment, performed at the Hanford Engineering Development Laboratory, will be studied; this experiment exhibited a strong stratification, at all times, above a growing water pool. JERICHO and AEROSOLS-B2 are part of the Ensemble de Systèmes de Codes d'Analyse d'Accident des Réacteurs à Eau (ESCADRE) code system, a tool for evaluating the response of a nuclear plant to severe accidents. These two codes are used here to simulate respectively the thermal hydraulics and the associated aerosol behavior. Code results have shown that modeling large containment thermal hydraulics without taking into account the stratification phenomenon leads to large overpredictions of containment pressure and temperature. If the stratification, above the water pool, is modeled as a zone with a higher steam condensation rate and a higher thermal resistance (that is acting as a barrier to heat exchanges with the upper and larger compartment), ESCADRE predictions match experimental data quite well. The stratification region is believed to be able to affect aerosol behavior; aerosol settling is improved by steam condensation on particles and by diffusiophoresis and thermophoresis. In addition, the lower aerosol concentration throughout the stratification might cause a nonnegligible aerosol concentration gradient and consequently a driving force for the motion of smaller particles toward the pool.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Condensed Matter Physics
Passalacqua, R., Tarabelli, D., & Renault, C. (1996). Light water reactor aerosol containment experiment LA4 simulated by JERICHO and AEROSOLS-B2 codes. Nuclear Technology, 116(3), 283 - 292. https://doi.org/10.13182/NT96-A35284