WATEQ4F -- User's manual with revised thermodynamic data base and test cases for calculating speciation of major, trace and redox elements in natural waters

1991 ◽  
Author(s):  
J.W. Ball ◽  
D. Kirk Nordstrom
Keyword(s):  
Data Base ◽  
Thermodynamic Data ◽  
Natural Waters ◽  
Test Cases

The Modeler's Influence on Calculated Solubilities for Performance Assessments at the Äspö Hard-Rock Laboratory

1999 ◽  
Vol 556 ◽  
Author(s):  
A. T. Emrén ◽  
Randy Arthur ◽  
Pierre D. Glynn ◽  
Jude McMurry
Keyword(s):  
Data Base ◽  
Thermodynamic Data ◽  
Hard Rock ◽  
Solid Phase ◽  
Performance Assessments ◽  
Test Cases ◽  
Data Bases ◽  
Standard Data ◽  
System A ◽  
Rock Laboratory

AbstractFour researchers were asked to provide independent modeled estimates of the solubility of a radionuclide solid phase, specifically Pu(OH)4, under five specified sets of conditions. The objectives of the study were to assess the variability in the results obtained and to determine the primary causes for this variability.In the exercise, modelers were supplied with the composition, pH and redox properties of the water and with a description of the mineralogy of the surrounding fracture system A standard thermodynamic data base was provided to all modelers. Each modeler was encouraged to use other data bases in addition to the standard data base and to try different approaches to solving the problem.In all, about fifty approaches were used, some of which included a large number of solubility calculations. For each of the five test cases, the calculated solubilities from different approaches covered several orders of magnitude. The variability resulting firom the use of different thermodynamic data bases was in most cases, far smaller than that resulting from the use of different approaches to solving the problem.

Validation of the SKBU1 Uranium Thermodynamic Data Base for its use in Geochemical Calculations with EQ3/6

1988 ◽  
Vol 127 ◽  
Author(s):  
Jordi Bruno ◽  
Ignasi Puigdomenech
Keyword(s):  
Data Base ◽  
Thermodynamic Data ◽  
Carbonate Concentration ◽  
Wide Range

ABSTRACTA validation of the SKBUl uranium thermodynamic data base is performed. Experimental solubilities for schoepite, rutherfordite, UO2(am) and UO2(c) determined in a wide range of pH, PCO2, carbonate concentration and temperature are compared to calculated ones by using EQ3NR.

The Solubility of Actinides in the Near-Field

1985 ◽  
Vol 50 ◽  
Author(s):  
F. T. Ewart ◽  
R. M. Howse ◽  
H. P. Thomason ◽  
S. J. Williams ◽  
J. E. Cross
Keyword(s):  
Data Base ◽  
Thermodynamic Data ◽  
Near Field ◽  
Geochemical Modelling ◽  
Actinide Elements

AbstractThe solubility of some of the radiologically important actinide elements have been determined in a water whose chemistry was representative of that believed to exist in potential repositories in the U.K. The solubilities of the actinides have been determined as a function of the pH of the water. The results of these experiments have been compared with the results of predictions made using the PHREEQE geochemical modelling code in order to test and validate the data base used in the model. In the light of these comparisons, suggestions are made for alternative values for the thermodynamic data and for further studies.

scholarly journals The Chemkin Thermodynamic Data Base

1990 ◽  
Author(s):  
R. Kee ◽  
F. Rupley ◽  
J. Miller
Keyword(s):  
Data Base ◽  
Thermodynamic Data

scholarly journals Nagra/PSI Chemical Thermodynamic Data Base 01/01

2002 ◽  
Vol 90 (9-11) ◽  
Author(s):  
W. Hummel ◽  
U. Berner ◽  
E. Curti ◽  
F. J. Pearson ◽  
T. Thoenen
Keyword(s):  
Radioactive Waste ◽  
Data Base ◽  
Thermodynamic Data ◽  
Critical Appraisal ◽  
Fission Products ◽  
Performance Assessments ◽  
The Other ◽  
Chemical Thermodynamic ◽  
Carbonate Complexes

SummaryThe Nagra/PSI Chemical Thermodynamic Data Base has been updated to support performance assessments of the planned Swiss repositories for radioactive waste. The update from version 05/92 to 01/01 involved major revisions for most of the actinides and fission products. Altogether, more than 70% of the database contents have been revised. Data for U, Np, Pu, Am and Tc recommended by the NEA TDB project were considered in the update. Thermodynamic data for Th, Sn, Eu, Pd, Al, and solubility and metal complexation of sulphides and silicates were extensively reviewed. Data for Zr, Ni and Se were examined less rigorously as these elements are currently being reviewed in phase II of the NEA TDB project. Our experiences from this two year team effort can be summarised as follows. Detailed in-house reviews and critical appraisal of NEA recommendations greatly improved the chemical consistency and quality of the selected data. On the other hand, we could discern major gaps in the data, especially missing carbonate complexes. In some systems,

Metastable Phase Formation in Multi-Component Aluminium Alloys

2007 ◽  
Vol 263 ◽  
pp. 31-40 ◽  
Author(s):  
Alfred Peter Miodownik ◽  
N. Saunders ◽  
J.P. Schille ◽  
Zhan Li Guo
Keyword(s):  
Data Base ◽  
Phase Formation ◽  
Aluminium Alloys ◽  
Thermodynamic Data ◽  
Metastable Phase ◽  
Equilibrium Conditions ◽  
Metastable Structures ◽  
Metastable Phase Formation ◽  
Commercial Aluminium ◽  
Cct Diagrams

Many Aluminium alloys use the precipitation of metastable phases to generate optimum properties. The effect of including additional structures such as θ’ and GP zones is described in the context of a hierarchy of metastable structures. Extending a Thermodynamic data base that has been designed solely to deal with equilibrium conditions is a vital prerequisite to handling the heattreatment of aluminium alloys. It is then possible to generate TTT and CCT diagrams, using the Johnson-Mehl-Avrami treatment previously applied in to other materials providing provision is made for the presence of supersaturated quenched-in vacancies. Calculations using JMatPro are given for the expected behavior of commercial aluminium alloys of increasing complexity, including AA319, AA6061 and AA7075.

Chemical Speciation of Hg(II) with Environmental Inorganic Ligands

2004 ◽  
Vol 57 (10) ◽  
pp. 993 ◽  
Author(s):  
Kipton J. Powell ◽  
Paul L. Brown ◽  
Robert H. Byrne ◽  
Tamas Gajda ◽  
Glenn Hefter ◽  
...  
Keyword(s):  
Organic Matter ◽  
Complex Formation ◽  
Numerical Modelling ◽  
Thermodynamic Data ◽  
Natural Waters ◽  
Chemical Speciation ◽  
Interaction Coefficients ◽  
Low Concentrations ◽  
The Common ◽  
Inorganic Ligands

Abstract Complex formation between Hg(ii) and the common environmental ligands Cl−, OH−, CO32−, SO42−, and PO43− can have profound effects on Hg(ii) speciation in natural waters with low concentrations of organic matter. Hg(ii) is labile, so its distribution among these inorganic ligands can be estimated by numerical modelling if reliable values for the relevant stability constants are available. A summary of critically reviewed constants and related thermodynamic data is presented. Recommended values of log10βp,q,r° and the associated reaction enthalpies, ΔrHm°, valid at Im = 0 mol kg−1 and 25°C, along with the equations and specific ion interaction coefficients required to calculate log10βp,q,r values at higher ionic strengths and other temperatures are also presented. Under typical environmental conditions Hg(ii) speciation is dominated by the reactions Hg2+ + 2Cl− ↔ HgCl2(aq) (log10β2° = 14.00 ± 0.07), Hg2+ + Cl− + H2O ↔ Hg(OH)Cl(aq) + H+ (log10β° = 4.27 ± 0.35), and Hg2+ + 2H2O ↔ Hg(OH)2(aq) + 2H+ (log10*β2° = −5.98 ± 0.06).

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