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

Published online by Cambridge University Press:  10 February 2011

A. T. Emrén
Affiliation:
Dept. Nuclear Chemistiy, Chalmers University of Technology, S-41296 Göteborg, Sweden, allan@nc.chalmers.se
Randy Arthur
Affiliation:
QuantiSci, Inc., 3900 So. Wadsworth Blvd., #555, Denver, CO 80235, USA, r_arthur@quantisci.com
Pierre D. Glynn
Affiliation:
U.S. Geological Survey, 432 National Centre, Reston, VA, 20191, USA, pglynn@usgs.gov
Jude McMurry
Affiliation:
AECL, Whiteshell Laboratories, Pinawa, MB ROE1L0 Canada, mcmunryj@aecl.ca
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Abstract

Four 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.

Type
Research Article
Copyright
Copyright © Materials Research Society 1999

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References

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