A new sodium plugging model, based on first principles, has been developed and is described in this work. It integrates experiment data on the rate of formation of sodium oxide deposits, obtained from the upgraded Sodium Plugging Loop (SPL) at Argonne National Laboratory, with previous literature data referred to both small and large channels. In the SPL, deposits are caused by the cooling-induced precipitation, upon the stainless steel walls, of sodium oxide from dissolved oxygen impurities. The novel feature of the model consists of modeling the sodium oxide deposits as highly porous, with most of the deposit volume occupied by sodium interstitial to sodium oxide, as revealed during previous investigations. The new first principles plugging model is shown to provide a consistent understanding of the currently existing body 'of data encompassing turbulent and laminar forced convection flow regimes as well as laminar natural convection flow of sodium, small and large sodium channel sizes, and orifice plates and lengthy sodium channels.
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