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.

Polyphase Ceramic and Glass-Ceramic forms for Immobilizing ICPP High-Level Nuclear Waste

1983 ◽  
Vol 26 ◽  
Author(s):  
Alan B. Harker ◽  
John F. Flintoff
Keyword(s):  
Glass Ceramic ◽  
Glass Matrix ◽  
Hot Isostatic Pressing ◽  
Glass Frit ◽  
Processing Plant ◽  
Chemical Processing ◽  
Chemical Additives ◽  
High Level Nuclear Waste ◽  
High Level ◽  
Consolidation Temperature

ABSTRACTPolyphase ceramic and glass-ceramic forms have been consolidated from simulated Idaho Chemical Processing Plant wastes by hot isostatic pressing calcined waste and chemical additives at 1000°C or less. The ceramic forms can contain over 70 wt% waste with densities ranging from 3.5 to 3.85 g/cm3, depending upon the formulation. Major phases are CaF2, CaZrTi2O7, CaTiO3, monoclinic ZrO2, and amorphous intergranular material. The relative fraction of the phases is a function of the chemical additives (TiO2, CaO, and Si02) and consolidation temperature. Zirconolite, the major actinide host, makes the ceramic forms extremely leach resistant for the actinide simulant U238. The amorphous phase controls the leach performance for Sr and Cs which is improved by the addition of SiO2. Glass-ceramic forms were also consolidated by HIP at waste loadings of 30 to 70 wt% with densities of 2.73 to 3.1 g/cm3 using Exxon 127 borosilicate glass frit. The glass-ceramic forms contain crystalline CaF2, Al2O3, and ZrSiO4 (zircon) in a glass matrix. Natural mineral zircon is a stable host for 4+ valent actinides.

GEL Adsorption Processing for Waste Solidification in 'NZP' Ceramics

1983 ◽  
Vol 26 ◽  
Author(s):  
L.J. Yang ◽  
S. Komarneni ◽  
R. Roy
Keyword(s):  
Zirconium Phosphate ◽  
Adsorption Process ◽  
Hydrothermal Conditions ◽  
Waste Solution ◽  
Waste Forms ◽  
Sodium Zirconium ◽  
Reducing Conditions ◽  
Adsorption Processing ◽  
Nzp Ceramics ◽  
Sodium Zirconium Phosphate

ABSTRACTSimulated PW-4b waste solution along with Na additive was mixed with Zr-P-O gel, dried and then fired to form the desired sodium zirconium phosphate, NaZr2 (PO4) 3 [NZP] ceramic. NZP and monazite were the only phases produced upon firing at 900°C with 10 to 40% of PW-4b mixed with the gel. CsZr2(PO4) 3 which is isostructural with NZP was also identified when fired under reducing conditions. The -200 mesh powders of these waste forms prepared under reducing conditions showed excellent leach resistance under hydrothermal conditions.Alternatively, PW-4b and Three Mile Island (TMI) wastes were adsorbed on Zr-P-O gel in a column. The gel was dried, pelletized and fired to form the desired [NZP] ceramic. Cesium was found to be selective on the Zr-P-O gel because no breakthrough of Cs was detected up to 38 column volumes of TMI waste. Thus, it is possible to use a tailored gel to sorb Cs and/or Sr from accident waste water and then fired the bed to form the [NZP] ceramic below 1000°C. The main advantages of the gel adsorption process are its simplicity and its enormous compositional flexibility.

Glass-Ceramic Waste Forms for Immobilizing Plutonium

1996 ◽  
Vol 465 ◽  
Author(s):  
T. P. O'Holleran ◽  
S. G. Johnson ◽  
S. M. Frank ◽  
M. K. Meyer ◽  
M. Noy ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
High Level Waste ◽  
Processing Plant ◽  
Chemical Processing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Diffraction Patterns ◽  
High Level

ABSTRACTResults are reported on several new glass and glass-ceramic waste formulations for plutonium disposition. The approach proposed involves employing existing calcined high level waste (HLW) present at the Idaho Chemical Processing Plant (ICPP) as an additive to: 1) aid in the formation of a durable waste form and 2) decrease the attractiveness level of the plutonium from a proliferation viewpoint. The plutonium, PuO2, loadings employed were 15 wt% (glass) and 17 wt% (glass-ceramic). Results in the form of x-ray diffraction patterns, microstructure and durability tests are presented on cerium surrogate and plutonium loaded waste forms using simulated calcined HLW and demonstrate that durable phases, zirconia and zirconolite, contain essentially all the plutonium.

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.

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
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