Transmission of Aerosol through Micro-Channel Flow

PHILIP JONES, Samuel Durbin, Adrian Perales, Sandia National Labs

     Abstract Number: 605
     Working Group: Health-Related Aerosols

Abstract
The formation of a stress corrosion crack (SCC) in the canister wall of a dry cask storage system (DCSS) has been identified as a potential issue for the long-term storage of spent nuclear fuel. The presence of an SCC in a storage system could represent a through-wall flow path from the canister interior to the environment. Modern, vertical DCSSs are of particular interest due to the commercial practice of using relatively high backfill pressures (up to approximately 800 kPa) in the canister to enhance internal natural convection. This pressure differential offers a comparatively high driving potential for blowdown of any particulates that might be present in the canister. In this study, the rates of gas flow and aerosol transmission of a spent fuel surrogate through an engineered microchannel with dimensions representative of an SCC were evaluated experimentally using coupled mass flow and aerosol analyzers. The microchannel opening diverges linearly from 13 μm on the upstream side to 27 μm on the downstream side. The width and depth are 12.7 mm and 8.89 mm respectively. Both polydisperse and 1-3 micron seed stock of cerium oxide, CeO2, were used as a surrogate aerosols to spent fuel. A pressurized tank containing air or helium was actively seeded with aerosols and allowed to discharge to ambient conditions through the microchannel while aerosol spectrometers measured conditions upstream and downstream of the simulated SCC. These testing efforts serve to better understand the effects of upstream particle size and driving pressure on the transmission of aerosolized spent fuel particles through a SCC during a hypothetical release.

SAND2024-06598A