Fixed-fugacity option for the EQ6 geochemical reaction path code

Delany, J.M.; Wolery, Thomas J.

doi:10.2172/59350

Cited by 12 publications

(17 citation statements)

References 9 publications

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“…The rate at which a reactant dissolves can be negative, in which case the "reactant" is actually a product precipitating according to the rate law instead of instantaneously to satisfy solubility equilibrium. This is the principle behind the option to specify precipitation kinetics [Delany, Puigdomenech, and Wolery, 1986]. Unfortunately, few kinetic data exist yet for geochemical precipitation reactions.…”

Section: K-4mentioning

confidence: 99%

Compliance Assessment Document for the Transuranic Wastes in the Greater Confinement Disposal Boreholes at the Nevada Test Site, Volume 2: Performance Assessment

Cochran¹,

Beyeler²,

Brosseau³

et al. 2001

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Intermediate depth disposal operations were conducted by the U.S. Department of Energy (DOE) at the DOE's Nevada Test Site (NTS) from 1984 through 1989. These operations emplaced highspecific activity low-level wastes (LLW) and limited quantities of classified, "special case" transuranic (TRU) wastes in 37 m (120-ft) deep, 3 m (10 ft) diameter Greater Confinement Disposal (GCD) boreholes.Four boreholes contain about 60,000 kg (132,000 lb.) of classified TRU waste packages, containing less than 330 curies of Plutonium-239. All of the TRU wastes emplaced in the GCD boreholes are classified for national security reasons and cannot be disposed of in the DOE's Waste Isolation Pilot Plant.The U.S. Environmental Protection Agency's (EPA's) 40 CFR 191 defines the requirements for protection of human health from disposed TRU wastes. This EPA standard sets a number of requirements, including probabilistic limits on the cumulative releases of radionuclides to the accessible environment for 10,000 years. This report presents the performance assessment (PA) that has been conducted to determine if disposal of TRU waste in the GCD boreholes complies with the EPA's 40 CFR 191 requirements.Sandia National Laboratories completed this PA using all available information and an Iterative PA Methodology, which focused work on uncertainty reduction in a cost-effective fashion that does not overestimate system performance and assured defensibility. The simplicity of the conceptual models of the GCD disposal system allowed them to be implemented in Microsoft ® Visual Basic™ macros in an Access™ database. This PA model is built from a mathematical expression for mass conservation that includes the operation of a number of transport processes, including dissolution, precipitation, reversible chemical sorption onto soil, advection, diffusion, dispersion, radioactive decay and ingrowth, plant uptake, and bioturbation. The mathematical model and implementing code was used to calculate a complementary cumulative distribution function of integrated normalized release to the accessible environment for 10,000 years and probability distributions of dose based on two exposure conditions for the 1,000 year individual protection requirements.The primary conclusions of this PA are that the disposal of TRU wastes in the GCD boreholes will, at most, result in minuscule doses to individuals, and that the GCD disposal system easily meets the EPA's 1985, 40 CFR 191 requirements for disposal of TRU waste. Further, there is a strong, reasonable expectation that actual system performance will be better than what is simulated in this PA.vi ACKNOWLEDGMENTS

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Section: K-4mentioning

confidence: 99%

Compliance Assessment Document for the Transuranic Wastes in the Greater Confinement Disposal Boreholes at the Nevada Test Site, Volume 2: Performance Assessment

Cochran¹,

Beyeler²,

Brosseau³

et al. 2001

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“…This option has been described elsewhere (Delany and Wolery, 1984). It assumes that the reacting system (of any of the above discussed types) is in contact with a large external gas reservoir, such that specified gas species move to or from that resewoir in order to maintain specified fixed fugacities in the reacting system.…”

Section: Systems Open To External Gas Reservoirsmentioning

confidence: 99%

“…References Nordstrom, D K , et al , 1979, A comparison Delany and Wolery (1984), Delany (1985), Jackson (1988). The examples presented here were run on a Sun SPARCstation IPC using optimized code, using the "W" format input files and the "RIO" com and hmw data files.…”

mentioning

confidence: 99%

EQ6, a computer program for reaction path modeling of aqueous geochemical systems: Theoretical manual, user`s guide, and related documentation (Version 7.0); Part 4

Wolery¹,

Daveler²

1992

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226

179

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“…Once saturation of a reactant occurs, its dissolution rate is set to zero. The incorporation of precipitation rate laws as a function of reaction progress and time is currently in progress and will be available in the next release version of the EQ3/6 software package expected in early 1986 [see Delany et al (1986) for a description of the precipitation kinetics option].…”

Section: Eq3/6 Software Packagementioning

confidence: 99%

Reaction of Topopah Spring tuff with J-13 water: a geochemical modeling approach using the EQ3/6 reaction path code

Delany¹

1985

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DISCLAIMERThis report wat prepared at an account of work iponiored by an agency of the United States Government. Neither Ike United States Government nor any agency thereof, nor any of their em ployed, make* any warranty, expreai or implied, or aaiiimei any legal liability or responsi bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herain do not necessarily state or reflect those of the United Stales Government or any agency thereof.

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Fixed-fugacity option for the EQ6 geochemical reaction path code

Cited by 12 publications

References 9 publications

Compliance Assessment Document for the Transuranic Wastes in the Greater Confinement Disposal Boreholes at the Nevada Test Site, Volume 2: Performance Assessment

Compliance Assessment Document for the Transuranic Wastes in the Greater Confinement Disposal Boreholes at the Nevada Test Site, Volume 2: Performance Assessment

EQ6, a computer program for reaction path modeling of aqueous geochemical systems: Theoretical manual, user`s guide, and related documentation (Version 7.0); Part 4

Reaction of Topopah Spring tuff with J-13 water: a geochemical modeling approach using the EQ3/6 reaction path code

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