The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
Tae M. Ahn - One of the best experts on this subject based on the ideXlab platform.
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Multiple lines of evidence for performance of the canister and Waste form in long-term Nuclear Waste Disposal: Reviews
Progress in Nuclear Energy, 2016Co-Authors: Tae M. AhnAbstract:Abstract The time scales required for Nuclear Waste Disposal are very large compared with those for other engineering endeavors. Because of this, there are many uncertainties associated with the quantitative performance assessment of canisters containing high-level radioactive Waste in a Waste form. Multiple lines of evidence can be helpful in building confidence in the long-term behavior (corrosion and dissolution) of the canister and Waste form. These lines of evidence are derived from long-term supports and probabilistic models and developed based on shorter term tests, bounding and conservative approaches, and available observations on natural analogs. This paper presents the progress made for important lines of evidence considered in quantitatively assessing radionuclide release behavior from canisters and Waste forms. This paper considers risk-significant issues for canisters and Waste forms (i.e., risk informed approach) in the probabilistic performance assessment of the Disposal system which has also other components such as geology and hydrology.
François Gauthier-lafaye - One of the best experts on this subject based on the ideXlab platform.
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2 billion year old natural analogs for Nuclear Waste Disposal: the natural Nuclear fission reactors in Gabon (Africa)
Comptes Rendus Physique, 2002Co-Authors: François Gauthier-lafayeAbstract:Abstract Two billion years ago, the increase of oxygen in atmosphere and the high 235 U/ 238 U uranium ratio (>3%) made possible the occurrence of natural Nuclear reactors on Earth. These reactors are considered to be a good natural analogue for Nuclear Waste Disposal. Their preservation during such a long period of time is mainly due to the geological stability of the site, the occurrence of clays surrounding the reactors and acting as an impermeable shield, and the occurrence of organic matter that maintained the environment in reducing conditions, favourable for the stability of uraninite. Hydrogeochemical studies and modelling have shown the complexity of the geochemical system at Oklo and Bangombe (Gabon) and the lack of precise data about uranium and fission products retention and migration mechanisms in geological environments. To cite this article: F. Gauthier-Lafaye, C. R. Physique 3 (2002) 839–849.
Stefano Tarantola - One of the best experts on this subject based on the ideXlab platform.
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On the relative importance of input factors in mathematical models: Safety assessment for Nuclear Waste Disposal
Journal of the American Statistical Association, 2002Co-Authors: Andrea Saltelli, Stefano TarantolaAbstract:This article deals with global quantitative sensitivity analysis of the Level E model, a computer code used in safety assessment for Nuclear Waste Disposal. The Level E code has been the subject of two international benchmarks of risk assessment codes and Monte Carlo methods and is well known in the literature. We discuss the Level E model with reference to two different settings. In the first setting, the objective is to find the input factor that drives most of the output variance. In the second setting, we strive to achieve a preestablished reduction in the variance of the model output by fixing the smallest number of factors. The emphasis of this work is on how to define the concept of importance in an unambiguous way and how to assess it in the simultaneous occurrence of correlated input factors and non-additive models.
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Scenario and Parametric Uncertainty in GESAMAC. A Methodological Study in Nuclear Waste Disposal Risk Assessment.
Computer Physics Communications, 1999Co-Authors: David Draper, António Pereira, Pedro Prado, Andrea Saltelli, Ryan Cheal, Sonsoles Eguilior, Bruno Mendes, Stefano TarantolaAbstract:Abstract We examine a conceptual framework for accounting for all sources of uncertainty in complex prediction problems, involving six ingredients: past data, future observables, and scenario, structural, parametric, and predictive uncertainty. We apply this framework to Nuclear Waste Disposal using a computer simulation environment — GTMCHEM — which “deterministically” models the one-dimensional migration of radionuclides through the geosphere up to the biosphere. Focusing on scenario and parametric uncertainty, we show that mean predicted maximum doses to humans on the earth's surface due to 1–129, and uncertainty bands around those predictions, are larger when scenario uncertainty is properly assessed and propagated. We also illustrate the value of a new method for global sensitivity analysis of model output called extended FAST .
Michael E. Kraft - One of the best experts on this subject based on the ideXlab platform.
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Policy Design and the Acceptability of Environmental Risks: Nuclear Waste Disposal in Canada and the United States
Policy Studies Journal, 2000Co-Authors: Michael E. KraftAbstract:This article examines the controversial process of developing high-level Nuclear Waste Disposal policy in Canada, with some comparison to experience in the United States. It argues that a policy design perspective can assist in understanding the difficult social and political issues associated with Waste Disposal and the environmental and health risks that it poses. I examine several critical questions related to such an endeavor and link them to long-term goals of building a sustainable society. Success in formulating and implementing a Nuclear Waste policy in Canada will depend on the nation's capacity to create requisite processes of public participation. Particularly important are those actions that can help the public understand and assess environmental risks, including related ethical and social issues, and build public trust and confidence in the siting processes and the implementing agencies.
S.t. Reis - One of the best experts on this subject based on the ideXlab platform.
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Thermal characterization of iron phosphate glasses for Nuclear Waste Disposal
Optical Materials, 2011Co-Authors: A.s. Pinheiro, Z.m. Da Costa, Maria José Valenzuela Bell, V. Anjos, Noelio O. Dantas, S.t. ReisAbstract:This paper reports on the thermal properties of iron phosphate glasses with the following wt.% composition: 40Fe2O3–60P2O5. Such glasses are currently being investigated for Nuclear Waste Disposal. Open photoacoustic cell (OPC) and heat capacity techniques were performed to determine thermal diffusivity, thermal conductivity and heat capacity of the glasses. Results were compared with borosilicate glass where OPC and Thermal lens where performed. Moreover, the present paper demonstrates the semiconducting-like behavior of iron phosphate glasses.
