Hostname: page-component-8448b6f56d-mp689 Total loading time: 0 Render date: 2024-04-24T01:32:24.985Z Has data issue: false hasContentIssue false

Sodium Zirconium Phosphate [NZP] as a Host Matrix for High Level Radioactive Wastes

Published online by Cambridge University Press:  11 February 2011

Yoshimi Seida
Affiliation:
Nuclear Chemical Engineering Center, Institute of Research and Innovation, Takada 1201, Kashiwa, 277–0861, Japan
Mami Yuki
Affiliation:
Nuclear Chemical Engineering Center, Institute of Research and Innovation, Takada 1201, Kashiwa, 277–0861, Japan
Kazunori Suzuki
Affiliation:
Nuclear Chemical Engineering Center, Institute of Research and Innovation, Takada 1201, Kashiwa, 277–0861, Japan
Toshio Sawa
Affiliation:
Nuclear Chemical Engineering Center, Institute of Research and Innovation, Takada 1201, Kashiwa, 277–0861, Japan
Get access

Abstract

Various elements (Cs, Sr, Ba, Zr, Ru, Pd, Ce, Nd, Gd, Fe, Cr, Ni, Mo and Te) in the simulated high-level radioactive wastes generated from commercial PUREX reprocessing were immobilized by a ceramic solidification using sodium zirconium phosphate, NaZr2(PO4)3 as a host matrix. The convertibility of the elements to the specific M, A and X sites in NZP crystal structure was determined with consideration of stoichiometry, charge balance and ion size of each element. Small disk samples of NZP waste form containing the elements were prepared by the sol-gel synthesis followed by calcination and compression sinteration at high temperature. The physicochemical structures such as produced phase in the waste forms and dispersion of the embedded elements in the NZP waste forms were investigated by means of XRD and SEM/EDX. Chemical behavior of the embedded elements and the limit of substitution of the NZP structure for the elements were investigated by the series of analysis. Moreover, in order to increase the limit of substitution of NZP, the effectiveness of pretreatment with heating the sol-gel products at 473–773K was experimentally investigated. The capability of embedding of NZP for the elements in HLW has been discussed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1) Scheets, B. E., Komarneri, S., Fajun, W., Yang, L. J., Ollinen, M. and Roy, R., Stability of NZP Waste Forms and Their Application to ICPP Waste, Mat. Res. Soc. Symp. Proc., 44, 903910 (1985)Google Scholar
2) Troole, A. Y., Stefanovsky, S. V. and Bogomolova, L. D.: EPR of Fe3+ and Cr3+ ions in NZP ceramics, Mat. Res. Soc. Symp. Proc., 556, 99106(1999)Google Scholar
3) Hawkins, H. T. and Scheets, B. E.: Monophasic Sodium Zirconium Phosphate (NZP) as a Host Structure for The Immobilization of Reprocessed High-Level Commercial Wastes, Environmental Issues and Waste Management Technologies, 709715(1998)Google Scholar
4) Roy, R., Vance, E. R. and Alamo, J.: [NZP], A New Ceramic Radiophase for Ceramic Nuclear Waste Forms, Mat. Res. Bull., 17, 585589(1982)Google Scholar
5) Seida, Y., Yuki, M. and Suzuki, K.: Sodium Zirconium Phosphate [NZP] as Immobilization Matrix for High Level Nuclear Waste, Bull. Institute of Research and Innovation, 22(2), 47(2002)Google Scholar