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Hafnium Hydroxide Complexation and Solubility: the Impact of Hydrolysis Reactions on the Disposition of Weapons-Grade Plutonium

Published online by Cambridge University Press:  10 February 2011

G. Cerefice ,
M. Draye ,
K. Noyes  and
K. Czerwinski
G. Cerefice
Affiliation:
Nuclear Engineering Department, Massachusetts Institute of Technology, Cambridge, MA
M. Draye
Affiliation:
Nuclear Engineering Department, Massachusetts Institute of Technology, Cambridge, MA
K. Noyes
Affiliation:
Nuclear Engineering Department, Massachusetts Institute of Technology, Cambridge, MA
K. Czerwinski
Affiliation:
primary contact: Bldg. 24–210, 77 Mass. Ave., Cambridge, MA. 02139 kczer@mit.edu
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Abstract

The stability constants for the complexation of hafnium by hydroxide ions is investigated by potentiometric titration over a range of ionic strengths (1m = 0.1 to 6.6 molal). The stability constants are determined from the titration data using the HYPERQUAD suite of programs. The stability constants at infinite dilution are determined using the Specific Ion Interaction Theory from the stability constants determined by titration. The results are shown with the error given as 2 standard deviations.

log β11 (Hf(OH)3+) = 13.84 ± 0.54log β12 (Hf(OH)2 2+) = 25.71 ± 0.39log β13 (Hf(OH)3 +) = 36.24 ± 0.88log β14 (Hf(OH)4 0) = 45.52 ± 0.80

The solubility product of Hf(OH)4 (s) is determined in 0.1 M NaC1O4 by measuring the total hafnium in solution that is in equilibrium with an excess of hafnium hydroxide solid under an argon atmosphere. The total Hf concentration is determined by ICP-AES. The solubility product is determined using the stability constants measured for the H f hydrolysis products in 0.1 M NaClO4. The precipitate examined is confirmed to be a hydroxide by IR spectroscopy. For Hf(OH)4 (s) in 0.1 M NaC1O4, the solubility product is log Ksp (Hf(OH)4 (s)) = −51.8 ± 0.5

The solubility and stability constants determined are used, along with literature values for plutonium solubility and complexation constants, to examine the behavior of hafnium and plutonium under the conditions expected at Yucca Mountain.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 556: Symposium QQ – Scientific Basis for Nuclear Waste Management XXII , 1999 , 1025
Copyright
Copyright © Materials Research Society 1999

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References

REFERENCES

[1] Van Konynenburg, R. “Baseline Ceramic Formulation” Presentation. RW/MD Technical Exchange Meeting, Argonne National Laboratory. (10/1/97)Google Scholar
[2] Ebbinghaus, B. B. “Summary of Immobilization Form Development” Presentation RW/MD Technical Exchange Meeting. Lawrence Livermore National Laboratory. (9/1/98)Google Scholar
[3] Grenthe, I.; Plyasunov, A.; and Spahiu, K. “Estimation of Medium Effects on Thermodynamic Data”. Modelling in Aquatic Chemistry. Nuclear Energy Agency, OECD. Paris. (1997) pp. 32 5 - 4 2 7.Google Scholar
[4] Baes, C.F.; and Mesmer, R.E. The Hydrolysis of Cations. Krieger Publishing Co., Malabar, Florida. (1976) pp. 147–168.Google Scholar
[5] Smith, R.M.; and Martell, A.E. Critical Stability Constants, Volume 4: Inorganic Complexes. VCH Publishers, New York. (1988)Google Scholar
[6] FanghÄNel, Th; Neck, V; and Kim, J.I. “The Ion Product of H20, Dissociation Constants of HICO 3 and Pitzer Parameters in the System Na7/H'/OH-/HCO 3-/COf2/C104-/H 20 at 25°C “ J. Sol. Chem. 25, 327. (1996)Google Scholar
[7] Gans, P. Data Fitting in the Chemical Sciences. Wiley, Chichester. (1992)Google Scholar
[8] Gans, P.; Sabatini, A.; and Vacca, A. “Investigation of Equilibria in Solution: Determination of Equilibrium Constants with HYPERQUAD.” Talanta. 43, 10. (1996) pp. 1739–1753.Google Scholar
[9] Tsoulfanidis, N. Measurement and Detection of Radiation. Hemisphere Publishing. New York. 1983.Google Scholar
[10] BOC Gases. “Argon Information Sheet.” Available at http://www.boc.com/gases/index.htm. (1997)Google Scholar
[11] Lierse, C.. Chemisches Verhalten von Plutonium in Natorlichen, Aquatischen Systemen: Hydrolyse, Carbonatkomplexierung und Redoxreaktionen. Ph.D. Thesis. Institut ffr Radiochemie der Technischen Universitgt Miinchen. (4/7/85).Google Scholar
[12] Cerefice, G.; Draye, M.; Noyes, K.L.; and Czerwlnski, K. “Environmental Behavior of Hafnium for the Disposal of Weapons-Grade Plutonium.” Waste Management Symposium 98. Tucson, AZ. (3/4/98). http://www.wmsym.org/Google Scholar