Is there a build-up of radon gas within the IWCS at NFSS?
Yes, there was a buildup of radon gas in the IWCS shortly after the residues were sealed in this cell. Radon-222 ingrowth occurs at a rate proportional to its half-life of 3.82 days, and equilibrium conditions are quickly established between radon-222 and its short-lived decay products. These decay products are solid particulates which quickly attach to the surfaces of nearby solid particles. This natural decay process of a gas to solid charged particulates greatly limits the amount of gas buildup in the IWCS, and equilibrium conditions were established long ago.
