Repository logo


ANSTO Publications Online

Welcome to the ANSTO Institutional Repository known as APO.

The APO database has been migrated to version 8.3. The functionality has changed, but the content remains the same.

ANSTO Publications Online is a digital repository for publications authored by ANSTO staff since 2007. The Repository also contains ANSTO Publications, such as Reports and Promotional Material. ANSTO publications prior to 2007 continue to be added progressively as they are in identified in the library. ANSTO authors can be identified under a single point of entry within the database. The citation is as it appears on the item, even with incorrect spelling, which is marked by (sic) or with additional notes in the description field.

If items are only held in hardcopy in the ANSTO Library collection notes are being added to the item to identify the Dewey Call number: as DDC followed by the number.

APO will be integrated with the Research Information System which is currently being implemented at ANSTO. The flow on effect will be permission to publish, which should allow pre-prints and post prints to be added where content is locked behind a paywall. To determine which version can be added to APO authors should check Sherpa Romeo. ANSTO research is increasingly being published in open access due mainly to the Council of Australian University Librarians read and publish agreements, and some direct publisher agreements with our organisation. In addition, open access items are also facilitated through collaboration and open access agreements with overseas authors such as Plan S.

ANSTO authors are encouraged to use a CC-BY licence when publishing open access. Statistics have been returned to the database and are now visible to users to show item usage and where this usage is coming from.

Discover

Communities in ANSTO Publications Online

Select a community to browse its collections.

Now showing 1 - 5 of 5

Recent Submissions

  • Thumbnail Image
    Item type: Item ,
    Determination by x-ray fluorescence of Caesium and other elements from Hanford waste simulates in the application of Synroc for high level radioactive waste remediation
    (Australasian Ceramic Society, 1998) Foy, JJ; Blagojevic, N
    At the Hanford Reservation near Richland, USA, there is a complex of 149 single-shelled tanks (SSTs) and 28 double-shelled tanks (DSTs) storing 9.7 x 1018 Bq (260 MCi) of radioactive waste awaiting remediation [1]. The Synroc process [2] developed by the Australian Nuclear Science and Technology Organisation (ANSTO) at Lucas Heights may be able to provide an effective solution for permanent containment and immobilisation of the highly radioactive caesium (137Cs) component of the Hanford waste. Decontamination of the liquid component of the waste, plus sludge washings, involves the absorption of caesium (Cs) on a suitable inorganic ion-exchange material. For Synroc, Cs-loaded sodium silico-titanate [4] would be a suitable precursor. We are preparing this ion-exchanger and a screening study using distribution coefficients (Kd) as a measure of efficiency is being undertaken. This work entails precise analysis of Cs and this forms the subject of the present paper. The concentration of caesium in Hanford waste simulates can be determined by various techniques. The Los Alamos National Laboratory has used radioactive tracers for simulates with a caesium concentration of 6 μg.l-1 [3]. Sandia National Laboratories have used flame atomic absorption spectrophotometry (AAS) [4]. At Lucas Heights Research Laboratories Cs in solution has been determined by electrothermal atomic absorption spectrophotometry (AASET) which has a detection limit of 2 μg.l-1 [5]. When Cs is absorbed on a solid matrix, analysis is further complicated. Quantitative chemical analysis by solution techniques requires sample preparation. An initial step of taking up minerals in a suitable flux (e.g. lithium metaborate) is uncomplicated, but with compounds containing titanium (Ti), the next step of making a solution, requires a special procedure involving a quenching liquid containing 5 % (v/v) of 30 % (w/v) hydrogen peroxide mixed with 2.5 % (w/v) tartaric acid dissolved in 3 % (v/v) nitric acid [6]. To avoid problems associated with having to quantitatively dissolve titanates to form stable solutions for subsequent analysis of Cs and other elements by atomic absorption spectrophotometry or inductively coupled plasma mass spectrometry (ICP-MS), analysis of solid material by wavelength dispersive X-ray fluorescence (WDXRF) was selected for this study. An advantage of WDXRF is that it is a multi-element technique capable of determining Cs and all other elements present in the liquid Hanford simulate and solid ion-exchange materials. Ti analysis by WDXRF is a common standard procedure for rocks and minerals and the analytical parameters are well known. XRF has also been used for the analysis of the chemical composition of sodium titanate [7] so the analysis of sodium silico-titanates should have few complications. For XRF the form of sample preferred for presentation to the detector is a glass disc. The major concern with Cs analysis that there may be some loss of this element during the preparation of the glass disc, because Cs had been found to volatilise from borosilicate glass melts [8]. While powders can be analysed by XRF, relatively large amounts ( 6 to 10 g ) are needed and there are other technical problems such as the difficulty of duplicating particle size and controlling the homogeneity of the sample, for the reasons analysis in the form of powders is not suitable for precision analysis.
  • Thumbnail Image
    Item type: Item ,
    Production of titanate microspheres by sol-gel and spray-drying
    (Australasian Ceramic Society, 1998) Sizgek, E; Bartlett, JR; Brungs, M
    Synroc is a multi-component titanate ceramic, designed to immobilise High Level Waste (HLW) from nuclear fuel reprocessing plants [1]. The Synroc concept involves immobilising the elements present in HLW within an assemblage of mutually compatible, thermodynamically stable mineral phases, namely hollandite (BaAl2Ti6O16), zirconolite (CaZrTi2O7), perovskite (CaTiO3) and anatase (TiO2). These minerals are formed during calcination and hot-pressing of a precursor powder containing TiO2, ZrO2, Al2O3, BaO and CaO in relative mass abundances of 71.4, 6.6, 5.4, 5.6 and 11 percent, respectively. Synroc precursor powders have been previously produced by various methods, such as oxide and alkoxide-hydrolysis routes [2]. However, various technological aspects of HLW processing make the use of free-flowing, dust-free, highly sinterable precursor powders desirable. Such powders have been produced by spray-drying colloidal precursors, yielding microspherical particles with controlled morphology [3]. These particles were readily impregnated with 20 wt% simulated HLW solutions, calcined at 750°C and subsequently hot-pressed to produce dense Synroc monoliths. This paper discusses the preparation of the microspherical precursor particles by spray-drying and
  • Thumbnail Image
    Item type: Item ,
    Aqueous milling and near net shape forming of SiAlON ceramics
    (Australasian Ceramic Society, 1998) Bendeich, PJ; Walls, PA
    A relatively new technique known as “Gelcasting” has the potential for producing near net shaped ceramics in large or small quantities without the limitations of conventional processing techniques such as difficult binder removal, formation of density gradients in the green state or limited shape complexity. The gelcasting technique involves dispersing a ceramic powder in a solution containing an organic monomer. Green ceramic articles are then formed by pouring the dispersion into a mould and polymerising the monomer to form a gel that retains the shape of the mould. Drying and sintering follow to produce a dense near net shape ceramic component. A major disadvantage to the gelcasting technique has been the need to use toxic acrylamide monomer as a gelling agent. Two aspects of the gelcasting process were examined in this study with a view to adapting it to the production of SiAlON components: (i) dispersion of multi component oxide and nonoxide ceramic powder mixes in aqueous media; and (ii) replacement of the organic monomer with a non-toxic polysaccharide (gellan gum) while attempting to retain controllable gelling properties. Milling aqueous based slurries has several advantages over their organic counterparts. Use of aqueous slurries reduces material costs, waste disposal and potential fire hazards. Aqueous milling also takes advantage of the enhanced effects of electrostatic forces which can aid in obtaining higher solids loadings. The SiAlON in this study was produced from the ceramic powder components Si3N4, AlN, Y2O3, and Al2O3. These components are usually milled in isopropylalcohol (IPA) to prevent hydrolysis of the AlN component. Hydrolysis of AlN in an aqueous media is a self sustaining process producing hydroxyl ions which raise the pH which in turn increases the rate of hydrolysis. The rate of hydrolysis has been reported to be significantly reduced by maintaining a pH below 7. AlN can be purchased with a hydrophobic protective coating. However, the milling process necessary to homogenise the powder components will remove this coating. Commercial SiAlON ceramics utilise synthesised 21R polytypoid as a replacement for AlN. This Al and N rich SiAlON phase, Al7O3N5, is resistant to hydrolysis during aqueous milling. Betz 1190 dispersant was used in conjunction with low pH to reduce the viscosity and raise the solids content of the slurries. The dispersant is a polymer with positively charged head groups distributed along it’s length. These head groups are attracted to the particles primarily by hydrogen/chemical bonding promoting dispersion in two ways; (i) the individual particles have a net positive charge, due primarily to the dispersant charge, this promotes long range repulsion between particles and (ii) the polymeric portion of the adsorbed dispersant acts as a physical (steric) barrier around the ceramic particles preventing short range particle-particle interaction. The low pH of the solution enhances the positive surface charge on the ceramic particle surfaces. Gellan gum has been developed as a substitute for agar in microbiological media. It has rheological properties superior to the those of agar and exhibits a gelling mechanism which could replace acrylamide monomer. Gellan gum can be prepared over a wide range of pH values, including acidic conditions. This provides versatility when selecting the method of dispersion. Gelled solutions can be formed with as little as 0.05 wt % in water. In addition it has low viscosity when heated above 75°C. It has several advantages over agar such as lower viscosity for a given solution concentration and the ability to form irreversible gels by the addition of divalent cations.
  • Thumbnail Image
    Item type: Item ,
    Diffusion of Nb in BaTi03 single crystal
    (Australasian Ceramic Society, 1998) Dupre, B; Ijjaali, M; Kowalski, K; Nowotny, J
    Diffusion coefficient of Nb in BaTiO3 was determined in the temperature range 1573-1773 K. The obtained diffusion data are in good agreement with the chemical diffusion coefficient of undoped BaTiO3. The process of Nb incorporation into BaTiO3 is not detectable below 1573 K.
  • Thumbnail Image
    Item type: Item ,
    Semiconducting properties of Cr-doped Co0
    (Australasian Ceramic Society, 1998) Dupre, B; Ijjaali, M; Kowalski, K; Nowotny, J
    Both electrical conductivity and thermopower were studied for Cr-doped CoO polycrystalline in the p(O2) range between 10-5 and 105 Pa and the temperature range between 1273 and 1373 K. The effect of Cr on the properties of CoO is discussed in terms of defect structure and semiconducting properties.