A theoretical investigation into the behavior of helium gas in the primary heat transport system (PHTS) of the SP-100 space nuclear power system was performed. Results indicate that helium gas dissolved in the primary coolant will most likely diffuse out of solution directly into existing bubbles i n the system accumulators/gas separators before reaching a concentration sufficient to drive a nucleation process elsewhere in the loop. Differences in individual loop flow rates of only a f e w percent were demonstrated to have a significant impact on the relative gas diffusion rates in the loop accumulators. Small bubbles (<15 pm radius) which m a y e s c a p e the gas separators will not expand from temperature and pressure changes as they circulate in the PHTS. Bubbles smaller than =40 pm in radius will eventually collapse by mass diffusion. NOMENCLATURE 2 As WA NuAB = mass transfer surface area (m ) -mass transfer rate (kg of He/sec) = dimensionless mass transfer Nusselt number (also known as the Sherwood Number) CO = analytic He concentration in 3 bulk Li (kg/m ) Cs = saturation concentration of He in 3 bulk Li (kg/m ) * Cs = saturation concentration of He in 3 Li at low flow accumulator (kg/m ) 3 AC, = CO-C = supersaturation (kg/m ) AC, = CO-C = supersaturation at low flow k * 3 accumulator (kg/m ) AC,/C = relative supersaturation (dimensionless) DAB = diffusion coefficient of He 2 in Li (m /sec) Dh D. = annulus inner diameter (m) = channel hydraulic diameter (m) DO K L n Pr pL pV P g R r r C r r' eq Re sc T V "b wA a r P P U $ = annulus outer diameter (m) = Henry's Law Constant (m /s ) = length of annulus (m) = amount of inert gas (moles) = Prandtl Number (dimensionless) = liquid pressure at operating 2 2 conditions (Pa) = liquid vapor pressure at temperature T (Pa) = inert gas partial pressure inside bubble (Pa) (J/mole -K ) = Universal Gas Constant = 8 . 3 1 4 4 = bubble radius (m) = vapor bubble radius at incipient nucleation (m) = bubble radius at mass and mechanical equilibrium (m) = radius of liquid meniscus in the equivalent cavity at surface pre -conditioning temperature and pressure (m). = Reynolds Number = pDhV/p (dimensionless) = Schmidt Number = p/pDAB (dimensionless) = liquid temperature (K) = liquid velocity in the channel (m/s) = gas bubble volume (m ) 3 = mass transfer rate (kg/s) = rc/r' (dimensionless) = ratio of gas removal rate at low flow accumulator to gas removal rate at full flow accumulator -AC:/AC, (dimensionless) = Li dynamic viscosity (kg/m-s) = Li density (kg/m ) = Li surface tension ( N , " ) = a measure of inert gas concentration in the nucleation cavity, a function of cavity geometry, contact angle, and moles of gas in the cavity (m-N/K) 3
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.