scholarly journals LONG-TERM HAZARD OF RADIOACTIVE WASTES PRODUCED BY THE ENRICHED URANIUM, Pu- -$sup 238$U, AND $sup 233$U--Th FUEL CYCLES.

1971 ◽  
Author(s):  
M. J. Bell ◽  
R. S. Dillon
Keyword(s):  
Radioactive Wastes ◽  
Fuel Cycles ◽  
Enriched Uranium

Achieving Resource Sustainability in China Through the Thorium Fuel Cycle in the Candu Reactor

2010 ◽  
Author(s):  
Peter G. Boczar ◽  
Bronwyn Hyland ◽  
Keith Bradley ◽  
Sermet Kuran
Keyword(s):  
Fuel Cycle ◽  
Close Approach ◽  
Natural Uranium ◽  
Fissile Material ◽  
Energy Potential ◽  
Candu Reactors ◽  
Fuel Cycles ◽  
Resource Sustainability ◽  
Enriched Uranium

The CANDU® reactor is the most resource-efficient reactor commercially available. The features that enable the CANDU reactor to utilize natural uranium facilitate the use of a wide variety of thorium fuel cycles. In the short term, the initial fissile material would be provided in a “mixed bundle”, in which low-enriched uranium (LEU) would comprise the outer two rings of a CANFLEX® bundle, with ThO2 in the central 8 elements. This cycle is economical, both in terms of fuel utilization and fuel cycle costs. The medium term strategy would be defined by the availability of plutonium and recovered uranium from reprocessed used LWR fuel. The plutonium could be used in Pu/Th bundles in the CANDU reactor, further increasing the energy derived from the thorium. Recovered uranium could also be effectively utilized in CANDU reactors. In the long term, the full energy potential from thorium could be realized through the recycle of the U-233 (and thorium) in the used CANDU fuel. Plutonium would only be required to top up the fissile content to achieve the desired burnup. Further improvements to the CANDU neutron economy could make possible a very close approach to the Self-Sufficient Equilibrium Thorium (SSET) cycle with a conversion ratio of unity, which would be completely self-sufficient in fissile material (recycled U-233).

CAREM X INPRO Case Study

2004 ◽  
Author(s):  
Pablo C. Florido ◽  
Dari´o Delmastro ◽  
Daniel Brasnarof ◽  
Osvaldo E. Azpitarte
Keyword(s):  
Nuclear Reactor ◽  
Fuel Cycle ◽  
High Level Waste ◽  
Fuel Cycles ◽  
Surface Intermediate ◽  
Geological Repository ◽  
Enriched Uranium ◽  
Intermediate Storage ◽  
High Level

Argentina is performing CAREM X Nuclear System Case Study based on CAREM nuclear reactor and Once Through Fuel Cycle, using SIGMA for enriched uranium production, and a deep geological repository for final disposal of high level waste after surface intermediate storage in horizontal natural convection silos, to verify INPRO (International Project on Innovative Nuclear Reactors and Fuel Cycles) methodology. Projections show that developing countries could play a crucial role in the deployment of nuclear energy, in the next fifty years. This case study will be highly useful for checking INPRO methodology for this scenario. In this contribution to ICONE 12, the preliminary findings of the Case Study are presented, including proposals to improve the INPRO methodology.

Overview of the U.S. Department of Energy Advanced Waste Forms Development

2018 ◽  
Author(s):  
Kimberly Gray ◽  
John Vienna ◽  
Patricia Paviet
Keyword(s):  
Nuclear Fuel ◽  
Fuel Cycle ◽  
Nuclear Fuel Cycle ◽  
The United States ◽  
Department Of Energy ◽  
High Level Waste ◽  
Fuel Cycles ◽  
Waste Forms ◽  
The U.S

In order to maintain the U.S. domestic nuclear capability, its scientific technical leadership, and to keep our options open for closing the nuclear fuel cycle, the Department of Energy, Office of Nuclear Energy (DOE-NE) invests in various R&D programs to identify and resolve technical challenges related to the sustainability of the nuclear fuel cycle. Sustainable fuel cycles are those that improve uranium resource utilization, maximize energy generation, minimize waste generation, improve safety and limit proliferation risk. DOE-NE chartered a Study on the evaluation and screening of nuclear fuel cycle options, to provide information about the potential benefits and challenges of nuclear fuel cycle options and to identify a relatively small number of promising fuel cycle options with the potential for achieving substantial improvements compared to the current nuclear fuel cycle in the United States. The identification of these promising fuel cycles helps in focusing and strengthening the U.S. R&D investment needed to support the set of promising fuel cycle system options and nuclear material management approaches. DOE-NE is developing and evaluating advanced technologies for the immobilization of waste issued from aqueous and electrochemical recycling activities including off-gas treatment and advanced fuel fabrication. The long-term scope of waste form development and performance activities includes not only the development, demonstration, and technical maturation of advanced waste management concepts but also the development and parameterization of defensible models to predict the long-term performance of waste forms in geologic disposal. Along with the finding of the Evaluation and Screening Study will be presented the major research efforts that are underway for the development and demonstration of waste forms and processes including glass ceramic for high-level waste raffinate, alloy waste forms and glass ceramics composites for HLW from the electrochemical processing of fast reactor fuels, and high durability waste forms for radioiodine.

Evaluation of Long-Term Irradiation Field in Geological Disposal of High-Level Radioactive Wastes

2000 ◽  
Vol 37 (sup1) ◽  
pp. 310-315
Author(s):  
H Sawamura ◽  
K Nishimura ◽  
M Naito ◽  
T Ohi ◽  
Y Ishihara ◽  
...  
Keyword(s):  
Radioactive Wastes ◽  
Geological Disposal ◽  
Irradiation Field ◽  
High Level

scholarly journals Representation of estuarine, coastal and marine biosphere systems within post-closure performance assessments supporting geological disposal of higher activity radioactive wastes in the UK

2015 ◽  
Vol 79 (6) ◽  
pp. 1467-1474 ◽  
Author(s):  
R. C. Walke ◽  
M. C. Thorne ◽  
J. T. Smith ◽  
R. Kowe
Keyword(s):  
Sediment Accumulation ◽  
Radioactive Wastes ◽  
Performance Assessments ◽  
Geological Disposal ◽  
Marine Systems ◽  
Quantitative Evidence ◽  
Potential Contaminant ◽  
Estuarine Coastal ◽  
The Uk

AbstractRadioactive Waste Management Limited (RWM) is tasked with implementing geological disposal of the United Kingdom's (UK) higher activity radioactive wastes. This paper describes how RWM's biosphere modelling capability has been extended from a solely terrestrial model to allow potential contaminant releases to estuarine, coastal and marine systems around the UK to be represented. The new models aim to strike a balance between being as simple as can be justified, erring on the side of conservative estimates of potential doses, while also representing the features and processes required to reflect and distinguish UK coastal systems. Sediment dynamics (including meandering of estuaries and sediment accumulation) are explicitly represented in a simplified form that captures the accumulation and remobilization of radionuclides. Long-term transitions between biosphere systems (such as from a salt marsh to a terrestrial system) are outside the scope of the study. The models and supporting data draw on information about the UK that is representative of present-day conditions and represent potential exposures arising from both occupational and recreational habits.?Generic calculations demonstrate that potential doses to humans arising from releases to estuarine, coastal and marine systems are typically more than two orders of magnitude lower than those for equivalent releases to terrestrial systems via well water and groundwater discharge to soil. The extended capability (i) ensures that RWM is able to undertake assessments for potential coastal site contexts, if and when required, and (ii) provides RWM with quantitative evidence to support the principal focus on terrestrial releases ( particularly for more generic assessments).

scholarly journals A Critical Review of the Recent Improvements in Minimizing Nuclear Waste by Innovative Gas-Cooled Reactors

2008 ◽  
Vol 2008 ◽  
pp. 1-18 ◽  
Author(s):  
E. Bomboni ◽  
N. Cerullo ◽  
G. Lomonaco ◽  
V. Romanello
Keyword(s):  
Nuclear Waste ◽  
Critical Review ◽  
Simplified Models ◽  
Geological Disposal ◽  
Fuel Cycles ◽  
Multiple Recycling ◽  
High Level ◽  
Coupling Current ◽  
The University

This paper presents a critical review of the recent improvements in minimizing nuclear waste in terms of quantities, long-term activities, and radiotoxicities by innovative GCRs, with particular emphasis to the results obtained at the University of Pisa. Regarding these last items, in the frame of some EU projects (GCFR, PUMA, and RAPHAEL), we analyzed symbiotic fuel cycles coupling current LWRs with HTRs, finally closing the cycle by GCFRs. Particularly, we analyzed fertile-free and Pu-Th-based fuel in HTR: we improved plutonium exploitation also by optimizing Pu/Th ratios in the fuel loaded in an HTR. Then, we chose GCFRs to burn residual MA. We have started the calculations on simplified models, but we ended them using more “realistic” models of the reactors. In addition, we have added the GCFR multiple recycling option usingkeffcalculations for all the reactors. As a conclusion, we can state that, coupling HTR with GCFR, the geological disposal issues concerning high-level radiotoxicity of MA can be considerably reduced.

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