scholarly journals Comparison of Sodium Zirconium Phosphate-Structured HLW Forms and Synroc for High-Level Nuclear Waste Immobilization

1996 ◽  
Vol 465 ◽  
Author(s):  
V. N. Zyryanov ◽  
E. R. Vance
Keyword(s):  
Zirconium Phosphate ◽  
Hot Isostatic Pressing ◽  
Sodium Zirconium ◽  
Dissolution Behaviour ◽  
Metal Bellows ◽  
Order Of Magnitude ◽  
Precipitation Phenomena ◽  
Nuclear Waste Immobilization ◽  
High Level ◽  
Sodium Zirconium Phosphate

ABSTRACTThe incorporation of (a) Cs and Sr as; (b) simulated actinides, and (c) simulated Purex waste in sodium zirconium phosphate (NZP) has been studied. The samples were prepared by sintering, by hot pressing and by hot isostatic pressing in metal bellows containers. The short-term chemical durability of the phosphate-based material containing Purex waste was within an order of magnitude ofthat for Synroc-C, as measured by 7-day MCC-1 tests at 90°C. The dissolution behaviour showed evidence of re-precipitation phenomena, even after times as short as 28 days. Potential for improvement of NZP-based ceramics for HLW management is discussed.

Stability of NZP Waste Forms and their Application To ICCP Waste

1984 ◽  
Vol 44 ◽  
Author(s):  
B. E. Scheetz ◽  
S. Komarneni ◽  
W. Fajun ◽  
L. J. Yang ◽  
M. Ollinen ◽  
...  
Keyword(s):  
Zirconium Phosphate ◽  
Processing Plant ◽  
Chemical Processing ◽  
Stability Studies ◽  
Waste Forms ◽  
Sodium Zirconium ◽  
Phosphate Phase ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Sodium Zirconium Phosphate

AbstractThe crystal structure of NaZr2(PO4)3, (NZP), contains three distinct crystallographic sites which between them can readily accommodate the majority of elements that are present in high level nuclear waste. The applicability of this host phase to the immobilization of mixed zirconia/alumina waste from the Idaho Chemical Processing Plant (ICPP) was demonstrated. A waste form consisting of CaF2, a number of NZP phases and F-apatite was prepared and the results of leach testing reported. Detailed stability studies of the host sodium zirconium phosphate phase were also conducted as a function of temperature, pH and time.

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

2002 ◽  
Vol 757 ◽  
Author(s):  
Yoshimi Seida ◽  
Mami Yuki ◽  
Kazunori Suzuki ◽  
Toshio Sawa
Keyword(s):  
Zirconium Phosphate ◽  
Sol Gel ◽  
Radioactive Wastes ◽  
Charge Balance ◽  
Small Disk ◽  
Host Matrix ◽  
Waste Forms ◽  
Sodium Zirconium ◽  
High Level ◽  
Sodium Zirconium Phosphate

ABSTRACTVarious 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.

Comparison of sodium zirconium phosphate and calcium zirconium phosphate structures for the retention of fluoride

2013 ◽  
Vol 299 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Ambarish Dey ◽  
Amit Das Gupta ◽  
Debrata Basu ◽  
Ritu D. Ambashta ◽  
P. K. Wattal ◽  
...  
Keyword(s):  
Zirconium Phosphate ◽  
Sodium Zirconium ◽  
Sodium Zirconium Phosphate

Relationship Between Thermal Expansion and Crystal Chemical Parameters in Diborides

1986 ◽  
Vol 30 ◽  
pp. 503-510
Author(s):  
H.A. McKinstry ◽  
Lai Daik Chai ◽  
R.V. Sara ◽  
K.E. Spear
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Zirconium Phosphate ◽  
Hexagonal Structure ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Chemical Parameters ◽  
X Ray ◽  
Sodium Zirconium ◽  
Sodium Zirconium Phosphate

Thermal expansion is an interesting, ubiquitous and neglected property of materials. Recently, Lenain et al. (1985) and Limaye (1986) have been investigating anisotropy in the low-expansion structures of the sodium zirconium phosphate family. In the hexagonal structure one axis expands while another contracts. In going from the calcium to the strontium analog the anisotropy actually changes sign. A change in anisotropy between CrB2 and TiB2 had been observed by R.V. Sara (1960). The results in Fig. 1 obtained by high temperature x-ray diffraction measurements indicate that for TiB2 the thermal expansion of the c-axis is greater than the expansion of the a-axis, whereas for CrB2 the reverse is true.

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