scholarly journals Transient and Steady-State Radionuclide Transport Through Penetrations in Nuclear Waste Containers

1986 ◽  
Vol 84 ◽  
Author(s):  
P. L. Chambre ◽  
W. W.-L. Lee ◽  
C. L. Kim ◽  
T. H. Pigford
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Nuclear Waste ◽  
Porous Rock ◽  
Intimate Contact ◽  
Transfer Rates ◽  
Diffusive Mass Transfer ◽  
Solutions Of Equations ◽  
Multiple Holes ◽  
Significant Mass

AbstractIn this paper we analyze the transport of radionuclides through penetrations in nuclear waste containers. Penetrations may result from corrosion or cracks and may occur in the original container material, in degraded or corroded material, or in deposits of corrosion products. We do not consider how these penetrations occur or the characteristics of expected penetrations in waste containers. We are concerned only with the analytical formulation and solutions of equations to predict rates of mass transfer through penetrations of specified size and geometry. Expressions for the diffusive mass transfer rates through apertures are presented. We present numerical illustrations for steady-state mass-transfer rates through a circular hole, including concentration isopleths. The results are extended to multiple holes, including a criterion for hole spacing wherein superposition of single-hole solutions can be used. Results illustrated for holes in thin-walled containers show that significant mass transfer can occur even if a small fraction of the container area is perforated. We also illustrate the case of holes facing a water gap, instead of being in intimate contact with porous rock. In this case the radionuclide flux from many small holes approaches that from a bare waste cylinder.

scholarly journals Mass Transfer in a Geologic Environment

1984 ◽  
Vol 44 ◽  
Author(s):  
S. J. Zavoshy ◽  
P. L. Chambre' ◽  
T. H. Pigford
Keyword(s):  
Mass Transfer ◽  
Analytical Solution ◽  
Dissolution Rate ◽  
Surface Chemical Reaction ◽  
Porous Rock ◽  
Important Species ◽  
Rate Of Dissolution ◽  
Diffusive Mass Transfer ◽  
Dissolved Species ◽  
Surface Liquid

AbstractA new analytical solution is presented that predicts the rate of dissolution of species from a waste package surrounded by a wet porous medium. By equating the rate of diffusive mass transfer into the porous rock to the rate of liquid-surface chemical reaction, an analytical solution for the timedependent dissolution rate and the time-dependent concentration of dissolved species at the waste surface is obtained. From these results it is shown that for most of the important species in a package of radioactive waste the surface liquid quickly reaches near-saturation concentrations and the dissolution rate can be predicted by the simpler theory that assumes saturation concentrations in the surface liquid.

scholarly journals Mass Transfer Coefficients for a Non-Newtonian Fluid and Water With and Without Antifoam Agents

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Robert A. Leishear ◽  
Hector N. Guerrero ◽  
Michael L. Restivo ◽  
David J. Sherwood
Keyword(s):  
Mass Transfer ◽  
Nuclear Waste ◽  
Large Scale ◽  
Test Results ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Transfer Rates ◽  
Mass Transfer Processes ◽  
Fluid Levels ◽  
Oxygen Measurements

Mass transfer rates were measured in a large scale system, which is consisted of an 8.4 m tall by 0.76 m diameter column, containing one of the three fluids: water with an antifoam agent, water without an antifoam agent, and AZ101 simulant, which simulated a non-Newtonian nuclear waste. The testing contributed to the evaluation of large scale mass transfer of hydrogen in nuclear waste tanks. Due to its radioactivity, the waste was chemically simulated and due to flammability concerns, oxygen was used in lieu of hydrogen. Different liquids were used to better understand the mass transfer processes, where each of the fluids was saturated with oxygen, and the oxygen was then removed from the solution as air bubbled up or sparged through the solution from the bottom of the column. Air sparging was supplied by a single tube, which was co-axial to the column; the decrease in oxygen concentration was recorded, and oxygen measurements were then used to determine the mass transfer coefficients to describe the rate of oxygen transfer from solution. Superficial, average, sparging velocities of 2 mm/s, 5mm/s, and 10 mm/s were applied to each of the liquids at three different column fill levels, and mass transfer coefficient test results are presented here for combinations of superficial velocities and fluid levels.

Radionuclide Transport through Perforations in Nuclear Waste Containers

1987 ◽  
Vol 112 ◽  
Author(s):  
Cyrus K. Aidun ◽  
Sanford G. Bloom ◽  
Gilbert E. Raines
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Nuclear Waste ◽  
Wall Thickness ◽  
Release Rate ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Concentration Field ◽  
Analytical Models ◽  
Waste Form

AbstractPrevious analytical models for the steady-state radionuclide release rate through perforations in nuclear waste containers into the surrounding medium, are based on a zero wall thickness assumption. In this paper we investigate the effect of the wall thickness on the mass transfer rate through isolated circular holes. We solve the steady-state diffusion equation for the concentration field and derive a model based on the analytical solution. By direct comparison, we show that the zero wall thickness model overpredicts the mass transfer rate by about 1300 percent for a circular hole with 1 cm radius and a wall thickness of 10 cm. As expected, the zero-thickness model becomes even less accurate as the hole radius decreases; it predicts a greater release rate from a large number of small holes than the mass transfer rate from an uncontained waste form cylinder. In contrast, the results predicted by our model remain bounded for isolated holes and never exceed the mass transfer from an uncontained waste form.

Diffusive mass transfer in island films

1978 ◽  
Vol 125 (7) ◽  
pp. 489-525 ◽  
Author(s):  
Ya.E. Geguzin ◽  
Yu.S. Kaganovskii
Keyword(s):  
Mass Transfer ◽  
Diffusive Mass Transfer ◽  
Island Films
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