Prof.
Neil Hyatt
(University of Sheffield)
01/11/2017, 08:30
National and international collaborative waste management programs
Oral Presentation
Decommissioning and clean up of nuclear facilities requires the development of new technologies to condition radioactive wastes, producing passively safe waste packages of minimal volume, to reduce storage and disposal costs. We have applied hot isostatic pressing to demonstrate conceptual wasteforms for ion exchange materials and sludges present on the Sellafield site, UK, and Fukushima...
Dr
Greg Lumpkin
(ANSTO)
01/11/2017, 09:00
National and international collaborative waste management programs
Oral Presentation
With the aim of creating novel ceramics with high radiation tolerance and ionic mobility, multiple samples with A-B-O stoichiometries ranging from 215 to 227 were synthesized and characterized by a combination of SEM, XRD, and TEM methods. Single-phase defect-fluorite-type compounds with A = Sm or Yb and B = Ti, Zr, and/or Sn are reported; whereas, pyrochlore compounds were also found as a...
Dr
adel mesbah
(ICSM Marcoule, France)
01/11/2017, 09:15
National and international collaborative waste management programs
Oral Presentation
The share of nuclear energy in order to supply electricity continues to increase, which makes a growing need for more uranium resources. Currently uraninite (UO2) and coffinite (USiO4) are the two most abundant and exploited minerals. With the exhausting of these resources, other minerals are currently considered and are subject to multiple studies. Among them brannerite (UTi2O6) represents...
Mr
Sean Barlow
(University of Sheffield)
01/11/2017, 09:30
National and international collaborative waste management programs
Oral Presentation
Ce3NbO7 weberite-type materials, an inactive analogue for Am3NbO7, have potential use in americium radioisotope thermoelectric generators to be developed by the European Space Agency for scientific missions beyond the orbit of Jupiter. Ceramics with greater than 97% purity were synthesised by thermal solid-state reaction and analytically characterised by X-ray diffraction, neutron diffraction,...
Dr
Zhaoming Zhang
(ANSTO)
01/11/2017, 09:45
National and international collaborative waste management programs
Oral Presentation
A multi-phase titanate waste form was synthesized using high temperature sintering in air or Ar with the composition of Ca0.71Y0.088Ce0.52Hf0.22Ti2Ox. The phase assemblage was investigated as a function of the sintering atmosphere. X-ray diffraction measurements indicated that oxidizing sintering atmosphere (air) favors the formation of pyrochlore, whereas neutral environment (Ar) promotes the...
Mr
Robert Aughterson
(ANSTO)
01/11/2017, 10:00
National and international collaborative waste management programs
Oral Presentation
The structure types within the Ln2TiO5 (Ln = lanthanides) system have similarities with many of the proposed phases within the titanate ceramic waste-form Synroc. Certain compounds might also be suitable for inert matrix fuel applications. Previous studies have shown a relationship between lanthanide radii and polymorph type for the Ln2TiO5 system. By using multiple lanthanides the average...
Dr
Stéphanie Szenknect
(ICSM)
01/11/2017, 10:45
National and international collaborative waste management programs
Oral Presentation
Minerals belonging to the monazite family, REEPO4 (REE: Y, Sc, La to Dy) could incorporate in their structure substantial amounts of Th and U [1]. Moreover, monazites maintain their crystallinity even after geological times of exposure to self-irradiation. Therefore, this phase appears as a promising candidate for the specific conditioning of transuranic elements (AnIV,AnIII). Already, many...
Dr
adel mesbah
(Institut de Chimie Séparative de Marcoule, UMR 5257 CEA/CNRS/UM/ENSCM, Site de Marcoule, BP 17171, 30207 Bagnols-sur-Cèze cedex, France)
01/11/2017, 11:15
National and international collaborative waste management programs
Oral Presentation
Monazite, i.e. LnPO4 (Ln = La-Gd), has been widely studied as specific ceramic for the conditioning of trivalent and tetravalent actinides.1 Owing to its chemical and structural flexibility, the monazite allows a variety of possible substitutions following different mechanisms.2 Among them, the so-called cheralite-family, i.e. Ln1-2xCaxAnIVxPO4. In this frame, the major part of protocols...
Dr
Stefan Neumeier
(Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research - IEK-6: Nuclear Waste Management and Reactor Safety, 52425 Jülich, Germany)
01/11/2017, 11:30
National and international collaborative waste management programs
Oral Presentation
Phosphate ceramics with monazite structure are considered as potential waste forms for the conditioning of specific nuclear waste streams (e.g. minor actinides and plutonium) due to their outstanding properties. In this study, the incorporation of actinides (Cm3+ and Pu3+) into the monazite structure has been investigated combining X-ray diffraction (XRD) as well as X-ray absorption- (XAS) and...
Dr
adel mesbah
(ICSM Marcoule, France)
01/11/2017, 11:45
National and international collaborative waste management programs
Oral Presentation
The management and the conditioning of radwaste represents a major challenge in the nuclear industry. Therefore a variety of host matrices have been studied, including several phosphate based ceramics.1 They represent promising candidates for the specific conditioning of actinides (III, IV) owing to their easy way of preparation and high chemical durability.2
The incorporation of actinides in...
Dr
Eric R Vance
(ANSTO)
01/11/2017, 13:30
Oral Presentation
Spent fuel has long been unofficially classified as HLW which is cooled for a few years to allow the dissipation of short-lived fission products and then is to be contained in thick-walled Cu or carbon steel containers for deep repository disposal where it is argued that the containers will perform immobilisation for ~105 yr. However immobilisation assumes highly reducing conditions in which...
Dr
Yingjie Zhang
(ANSTO)
01/11/2017, 13:45
National and international collaborative waste management programs
Oral Presentation
Glass-ceramics have attracted recent attention as they have the advantage of combining the chemical flexibility of glasses with the excellent durability of ceramics, making them potential waste forms for the immobilization of actinide wastes with processing chemicals. Glass-ceramics based on titanate ceramic phases, e.g. zirconolite, pyrochlore and brannerite have been developed at ANSTO. The...
Ms
Stephanie Thornber
(University of Sheffield)
01/11/2017, 14:00
National and international collaborative waste management programs
Oral Presentation
The UK has over 100 tonnes of separated PuO2 stored at the Sellafield site. The UK policy for managing this plutonium stockpile is to reuse this material as MOx fuel. However, not all of the material is suitable for reuse and a proportion has been classified as higher activity waste. These plutonium wastes, and any material which is not ultimately reused, will require immobilization, in a...
Dr
Linggen Kong
(Australian Nuclear Science and Technology Organisation)
01/11/2017, 14:15
National and international collaborative waste management programs
Oral Presentation
The actinide immobilisation research group at ANSTO has been investigating pyrochlore glass-ceramics for plutonium immobilisation. A novel method of glass ceramic preparation via a soft chemistry route has been designed recently. Significant advantages over a more traditional mixed oxide route include removal of the need for an organic solvent in synthesis and milling steps, and product devoid...
Dr
Paul C. M. Fossati
(Imperial College London)
01/11/2017, 14:30
National and international collaborative waste management programs
Oral Presentation
High-Level Waste (HLW) resulting from fuel reprocessing is immobilised in a borosilicate glass matrix, particularly in France and the UK.
Some HLW components have higher melting points than the glass, and thus never disolve into the melt.
Other crystalline phases may also form during fabrication due to limited solubility.
Separation could also occur later through a process of...
Dr
Josef Matyas
(Pacific Northwest National Laboratory)
01/11/2017, 15:15
National and international collaborative waste management programs
Oral Presentation
Various volatile radionuclides are being released into gas streams and aqueous solutions during reprocessing of used nuclear fuel and vitrification of radioactive waste. Radioactive iodine-129 is of a particular concern because of its long half-life of 15.7 million years and the potential for biological processes to concentrate iodine. A number of materials are being developed worldwide to...
Prof.
John McCloy
(Washington State University)
01/11/2017, 15:45
National and international collaborative waste management programs
Oral Presentation
Iodine-129, released in the off-gas stream during nuclear fuel reprocessing, is problematic due to its long half-life, high mobility in the earth’s environment, incorporation into the human thyroid, and difficulty in immobilizing it using traditional vitrification methods. Iodosodalite (Na8Al6Si6O24I2) has been considered as to immobilize iodine-129 due to feasibility of synthesis at low...
Dr
EUGENIA KUO
(Australian Nuclear Science and Technology Organisation)
01/11/2017, 16:00
National and international collaborative waste management programs
Oral Presentation
Sodalites have been investigated experimentally for the capture and long-term containment of iodine-129, a significant and hazardous waste product of the nuclear fuel cycle. Sodalites are zeolite-type structures commonly occurring in nature in alkaline igneous rocks and having the prototype formula Na$_8$(AlSiO$_4$)$_6$Cl$_2$. The crystal structure is based around $\beta$-cages consisting of...
Prof.
Evgeny Alekseev
(Forschungszentrum Jülich)
01/11/2017, 16:15
National and international collaborative waste management programs
Oral Presentation
Using extreme pressure (10GPa/1200°C) we obtained a new modification of U2O5 with an extraordinary dense structure. The crystal structure of resulting HP (high pressure)-U2O5 is dramatically differs from ambient pressure polymorph so called delta-U2O5. The structure of HP-U2O5 is more related to the cubic UO2 than to the layered delta-U2O5. Using state of the art ab initio methods we reveal...
Mr
Gabriel Murphy
(University of Sydney)
01/11/2017, 16:45
Novel techniques in waste-form development (including glass, ceramic, metallic, and composite waste forms)
Oral Presentation
In situ investigations of nuclear waste form related materials under extreme conditions are highly desirable for understanding and optimising applications of these materials, however they are often exceedingly challenging from a safety and radiological perspective. As a part of our investigations into actinide materials, we have developed a number of novel experimental methodologies which...
Ms
Bella Zubekhina
(researcher, V.G. Khlopin Radium Institute (KRI), St-Petersburg, Russia)
01/11/2017, 17:00
National and international collaborative waste management programs
Oral Presentation
Immobilization of bulk liquid high level waste (HLW) in Synroc ceramic is well-known reliable way for final isolation of waste from biosphere. It is proposed the alternative method of synthesis of titanate Synroc-like ceramic. Radionuclide incorporation into crystalline titanate host-phases can be provided as a result of direct radionuclide sorption from liquid HLW using non-selective sorbent...
