A Single Phase ([Nzp]) Ceramic Radioactive Waste Form

1982 ◽  
Vol 15 ◽  
Author(s):  
Rustum Roy ◽  
L.J. Yang ◽  
J. Alamo ◽  
E.R. Vance
Keyword(s):  
Radioactive Waste ◽  
Single Phase ◽  
Waste Form ◽  
Chemical Model ◽  
Crystal Chemical ◽  
Ceramic Waste ◽  
Molar Ratios ◽  
Loading Level ◽  
Waste Forms ◽  
Waste Loading

ABSTRACTIt has been shown that between 10 and 20% of a simulated PW–4b radwaste composition can be incorporated into a single nhase with the NZP (= ‘MaZr2 P3 o12’) structure. By changing the P/Na and Zr/Na molar ratios (i.e., adjusting the crystal chemical model of where each ion is located in the structure) it has been possible to outline a very ‘forgiving’ compositional regime both at the 10% and the 20% waste loading level within which one obtains one ([NZP]) or two ([NZP] and [monazite]) phases. We have also succeeded in substituting Tio2 for Zro2 in making a TiO2-rich [NTP] waste form analogous to the [NZ]] materials.Thus we have succeeded in creating monophasic and diphasic ceramic waste forms which can be sintered below 1000° C. Only preliminary leach data have been obtained at 25° and 300°C, and they place this material with good ceramic forms.

scholarly journals Synroc development—Past and present applications

2017 ◽  
Vol 4 ◽  
Author(s):  
Eric R. Vance ◽  
Dorji T. Chavara ◽  
Daniel J. Gregg
Keyword(s):  
Glass Ceramic ◽  
Intermediate Level ◽  
Waste Form ◽  
Spent Fuel ◽  
Process Technology ◽  
Technology Platform ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Produce Glass ◽  
Waste Loading

ABSTRACTSynroc has evolved over the last 40 years from the titanate full-ceramics developed in the late 1970s to a technology platform that can be applied to produce glass, glass–ceramic, and ceramic waste forms and where there are distinct advantages in terms of waste loading and suppressing volatile losses.A first of a kind Synroc plant for immobilizing intermediate level waste arising from Mo-99 production is currently in detailed engineering at ANSTO.Since the year 2000, Synroc has evolved from the titanate full-ceramics developed in the late 1970s to a technology platform that can be applied to produce glass, glass–ceramic, and ceramic waste forms and where there are distinct advantages in terms of waste loading and suppressing volatile losses. Furthermore recent efforts have focused strongly on waste form development for plutonium-bearing wastes in the UK, for different options for the immobilization of Idaho calcines and most recently developing an engineered waste form for the intermediate level wastes arising from 99Mo production, for the Australian Nuclear Science and Technology Organisation (ANSTO). A variety of other studies are currently in progress, including engineered waste forms for spent fuel and investigating the proliferation risks for titanate-based waste forms containing highly enriched uranium or plutonium. This paper also attempts to give some perspective on Synroc waste forms and process technology development in the nuclear waste management industry.

Aging Studies of Pu-238 and -239 Containing Calcium Phosphate Ceramic Waste-forms

2013 ◽  
Vol 1518 ◽  
pp. 73-78 ◽  
Author(s):  
Shirley K. Fong ◽  
Brian L. Metcalfe ◽  
Randall D. Scheele ◽  
Denis M. Strachan
Keyword(s):  
Calcium Phosphate ◽  
Accelerated Aging ◽  
Waste Form ◽  
Calcium Phosphate Ceramic ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Aging Studies ◽  
Flow Through ◽  
Pyrochemical Reprocessing

ABSTRACTA calcium phosphate ceramic waste-form has been developed at AWE for the immobilisation of chloride containing wastes arising from the pyrochemical reprocessing of plutonium. In order to determine the long term durability of the waste-form, aging trials have been carried out at PNNL. Ceramics were prepared using Pu-239 and -238, these were characterised by PXRD at regular intervals and Single Pass Flow Through (SPFT) tests after approximately 5 yrs.While XRD indicated some loss of crystallinity in the Pu-238 samples after exposure to 2.8 x 1018 α decays, SPFT tests indicated that accelerated aging had not had a detrimental effect on the durability of Pu-238 samples compared to Pu-239 waste-forms.

Progress on Ongoing Waste form HIP projects at ANSTO

MRS Advances ◽  
2018 ◽  
Vol 3 (20) ◽  
pp. 1059-1064 ◽  
Author(s):  
Eric R. Vance ◽  
Dorji T. Chavara ◽  
Daniel J. Gregg
Keyword(s):  
Spent Nuclear Fuel ◽  
Technology Development ◽  
Hot Isostatic Pressing ◽  
Waste Form ◽  
Process Technology ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Produce Glass ◽  
Form Development ◽  
Year 2000

Abstract:Since the year 2000, Synroc has evolved from the titanate full-ceramic waste forms developed in the late 1970s to a hot isostatic pressing (HIP) technology platform that can be applied to produce glass, glass–ceramic, and ceramic waste forms and where there are distinct advantages over vitrification in terms of, for example, waste loading and suppressing volatile losses. This paper describes recent progress on waste form development for intermediate-level wastes from 99Mo production at ANSTO, spent nuclear fuel, fluoride pyroprocessing wastes and 129I. The microstructures and aqueous dissolution results are presented where applicable. This paper provides perspective on Synroc waste forms and recent process technology development in the nuclear waste management industry.

Densifications and mechanical properties of single-phase Gd2Zr2O7 ceramic waste forms with improved TRPO waste load

2020 ◽  
Vol 40 (13) ◽  
pp. 4613-4622
Author(s):  
Zhangyi Huang ◽  
Qiuyao Li ◽  
Yutong Zhang ◽  
Junjing Duan ◽  
Haomin Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Waste Load

scholarly journals INFLUENCE OF THE CRYSTAL-CHEMICAL STRUCTURE IN CALCIUM-PHOSPHATE NANOCOMPOSITE ON THE FORMATION OF ELECTROSURFACE AND ACID-BASIC PROPERTIES

2021 ◽  
Vol 6 (2) ◽  
pp. 89-99
Author(s):  
M. Troubitsin ◽  
Viet Hung Hoang ◽  
L. Furda
Keyword(s):  
Calcium Phosphate ◽  
Chemical Structure ◽  
Single Phase ◽  
Aqueous Suspension ◽  
Chemical Precipitation ◽  
Crystal Chemical ◽  
Active Centers ◽  
X Ray ◽  
Molar Ratios ◽  
Design Values

The single-phase modified nanostructured hydroxyapatites and biomimetic calcium-phosphate nanocomposite (BMHAP) doped by silicate and carbonate anions are synthesized by chemical precipitation in aqueous solutions. The chemical composition of the obtained samples is studied by energy dispersive X-ray spectroscopy using a scanning electron microscope. It is shown that the obtained molar ratios are close to the design values in all samples. The influence of different modifying ions in the crystal-chemical structure of hydroxyapatite (HAp) on the electrosurface properties of the synthesized products has been studied. Unmodified hydroxyapatite, silicate-substituted hydroxyapatite, and BMHAP particles are found to carry a negative charge in an aqueous suspension at pH = 7, while carbonate-substituted HAp particles had a positive charge. It is revealed that the introduction of silicate and carbonate anions into the HAp structure is accompanied by an increase in negative values of the zeta-potential from -1.05 to -4.29 mV. The change in the distribution of active centers on the surface of modified nanostructured hydroxyapatites is studied by the adsorption of acid-base indicators method with pKax in the range from -0.3 to +12.8. In contrast to stoichiometric hydroxyapatite, in BMHAP the neutral Bronsted centers prevails, and their concentration is 48.38 mmol-eq/g

The Sorption and Mechanical Properties of the Modified Concrete Matrix Used for Conditioning of Radioactive Waste

2009 ◽  
Author(s):  
Daniela Dogaru ◽  
Ortenzia Niculae ◽  
Gheorghe Dogaru ◽  
Gheorghita Jinescu ◽  
Octavian G. Duliu
Keyword(s):  
Mechanical Properties ◽  
Radioactive Waste ◽  
Bending Strength ◽  
The Other ◽  
Sorption Properties ◽  
Waste Form ◽  
Anionic Polyelectrolyte ◽  
Waste Forms ◽  
Laboratory Investigations ◽  
Concrete Matrix

The paper describes the results obtained in the laboratory investigations on the mechanical and sorption properties of the cement-based radioactive waste form containing two kinds of sludge in different concentrations. One of them simulates the sludge obtained by treatment of liquid radioactive effluents using an anionic polyelectrolyte named PA-type, and the other one simulates the sludge obtained by decontamination of contaminated surfaces using a hydrogel named pNaAc-type. The influence of the concentration of sludge on the compressive as well as on bending strength of the cement-based radioactive waste forms was studied. The sorption properties of two radionuclides were studied.

Towards a Silicate Matrix for the Immobilisation of Halide-rich Wastes

2013 ◽  
Vol 1518 ◽  
pp. 91-96 ◽  
Author(s):  
M. R. Gilbert
Keyword(s):  
Solid Solutions ◽  
Single Phase ◽  
Xrd Analysis ◽  
Inert Atmosphere ◽  
Secondary Phases ◽  
Silicate Matrix ◽  
Ceramic Waste ◽  
Waste Forms ◽  
Trivalent Actinides

ABSTRACTSingle-phase calcium chlorosilicate and sodalite, two potential ceramic waste-forms for the immobilisation of CaCl2-based pyroprocessing wastes, have been fabricated at temperatures below the volatilisation point of CaCl2. Solid solutions doped with Sm3+ as an inactive analogue for trivalent actinides have been fabricated and characterised. XRD analysis shows both phases will successfully accommodate Sm3+, with the sodalite in particular remaining single-phase. Fabrication of Sm-doped calcium chlorosilicate in air results in the formation of SmOCl and Ca(Si2O5) secondary phases, however, calcination in an inert atmosphere is shown to successfully retard the formation of SmOCl allowing for higher levels of doping.

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