An HMS/RRAC Analysis of A High-Level Radioactive Waste Tank Farm

[摘要] References(22)It has been observed that a high-level radioactive waste tank generated quantities of hydrogen and nitrous oxide mixture that are potentially well within flammability limits. These gases are produced from chemical and nuclear decay reaction in a slurry of radioactive waste materials. The slurry is covered by a thick crust and containing sodium nitrate and nitrite salts. Significant amounts of combustible and reactant gases accumulate under the crust over a 110- to 120-day period. These gases cause the crust to rupture, allowing the gases to vent into the air cover-gas space above the crust. We postulated an ignition source for the hydrogen/nitrousoxide/air mixture after it has vented into the cover gas, and we calculated the resulting pressure and temperature loading on the double-walled waste tank using the three-dimensional, time-dependent fluid dynamics coupled with the chemical kinetic computer code HMS (Hydrogen Mixing Studies).The waste tank farm has a ventilation system designed to maintain a slight negative gage pressure during normal operation. We modeled the ventilation system with TRAC (Transient Reactor Analysis Code), and we coupled these two best-estimate accident analysis tools to model the ventilation system response to pressures and temperatures generated by the hydrogen combustion. Significant pressure are produced by this event, which could possibly threaten the tank's integrity.

[学科分类] 环境科学（综合）