Pool aerosol retention

Aerosol physics during transport is modeled in MELCOR by MAEROS, which includes particle agglomeration and different retention mechanisms including thermophoresis, diffusiophoresis, brownian diffusion and gravitational deposition. Aerosol retention in water pools is of interest in the V-LPIS sequence, when water pools may exists above the ruptured pipe in the auxiliary building it could also be of interest in the water present in the secondary side of steam generators in the SGTR sequence. 

A-8a. K. Fischer and W. Hafher, Retention of Aerosols in Water Pools, BF-V38.070-01, Battelle Engineering Corp., Frankfurt am Main, Germany, March 1994, and A-8b. D.A. Powers, A Simplified Model of Decontamination by BWR Steam Suppression Pools,... 

MELCOR incorporates TRAPMELT models to treat the behavior of vapors released from the core. It includes nucleation in the gas volume condensation onto surfaces, such as on suspended aerosols and structures. Retention by water pools is evaluated by SPARC. MELCOR considers surface heating by decay energy and revaporization of previously deposited materials. This phenomenon could be of importance later in the accident, when support plates degrade and collapse into the water pools present in the bottom of the vessel releasing steam. 

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