Wasteforms for waste from advanced reprocessing
- PDF / 419,366 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 61 Downloads / 208 Views
Wasteforms for waste from advanced reprocessing
Y-H Hsieh 1, D. Horlait 1, S. Humphry-Baker 1, E.R. Vance 2, D.J. Gregg 2, L. Edwards 2, T.D. Waite 3 and W.E. Lee 1 1
Centre for Nuclear Engineering, Imperial College London, London, SW7 2AZ, United
Kingdom 2
Institute of Materials Engineering, Australian Nuclear Science and Technology Organization
(ANSTO), Kirrawee, NSW 2232, Australia 3 School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia ABSTRACT EURO-GANEX aims to recycle both major and minor actinides. As the final waste composition is free from actinides, adapted immobilization matrices should be developed. Synroc is a potential wasteform that has proven itself to be efficient in immobilizing high-level wastes (HLW). In this study, a new composition of Synroc, Synroc-Z, is designed and characterized. The key modification is in decreasing the amount of zirconolite phase, which is the main host phase for actinides and increasing the amount of other phases (hollandite and perovskite). As designed the obtained amount of zirconolite is lower than in Synroc-C compositions. Synroc-Z samples were synthesized with a waste loading of 20 wt.% at various temperatures and pressures via hot-pressing to determine the optimum process parameters, which were determined to be 1150-1200qC and 20 MPa, respectively. INTRODUCTION A number of processes are being developed to improve current reprocessing technology, PUREX (Plutonium Uranium Redox EXtraction), by further separating the remaining wastes [1]. A promising method is the so-called Group Actinide Extraction (GANEX) process, which primarily recycles major and minor actinides together [2]. A novel development of GANEX, called EURO-GANEX, has been designed and tested at NNL (National Nuclear Laboratory, UK) and JRC-ITU (Joint Research Centre- Institute for Transuranium Elements, Germany) [3,4]. EURO-GANEX tests at both institutions got very high recoveries of transuranium product (e.g. higher than 99.8% of recoveries in actinides and minor actinides at JRC-ITU hot cell test )[4]. The remaining radioactive waste stream is therefore likely
4255 Downloaded from https:/www.cambridge.org/core. University of Arizona, on 26 Apr 2017 at 00:36:28, subject to the Cambridge Core terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2017.217
to be exclusively fission products (FPs). This modification requires new immobilization matrices to be developed that are tailored to accommodating actinide-free waste streams [3,4]. A potential wasteform for immobilizing HLW from EURO-GANEX is Synroc (Synthetic rock). Synroc is a family of advanced crystalline ceramics comprised mainly of 4 titanate phases: hollandite, perovskite, zirconolite and rutile. Each phase incorporates a different set of radioactive waste elements (see Table I), therefore it is possible to tailor the matrices of Synroc to particular waste streams by adjusting the ratio of the different titanate components [5-7]. An excess of r
Data Loading...
