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Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
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Smarter waste strategies: Helping deliver on the promise of advanced nuclear
At COP28, held in Dubai in 2023, a clear consensus emerged: Nuclear energy must be a cornerstone of the global clean energy transition. With electricity demand projected to soar as we decarbonize not just power but also industry, transport, and heat, the case for new nuclear is compelling. More than 20 countries committed to tripling global nuclear capacity by 2050. In the United States alone, the Department of Energy forecasts that the country’s current nuclear capacity could more than triple, adding 200 GW of new nuclear to the existing 95 GW by mid-century.
A. Berge Gureghian, Yih-Tsuen Wu, Budhi Sagar, Richard B. Codell
Nuclear Technology | Volume 104 | Number 2 | November 1993 | Pages 272-296
Technical Paper | Special Issue on Waste Management / Radioactive Waste Management | doi.org/10.13182/NT93-A34890
Articles are hosted by Taylor and Francis Online.
Exact analytical solutions based on Laplace transforms are derived for describing the one-dimensional space- and time-dependent advective transport of a decaying species in a layered, fractured, saturated rock system. The rock layers are parallel and horizontal and of uniform thickness. The fracture intersects normally to the rock layers and is of varying aperture across its length. The fracture network is serial in nature and of uniform thickness within each layer. Fluid movement is assumed to be exclusive to the fracture network. These solutions, which account for advection in fracture, molecular diffusion into the rock matrix, adsorption in both fracture and matrix, and radioactive decay, predict the concentrations in both fracture and rock matrix and the cumulative mass in the fracture. The solute migration domain in both fracture and rock is assumed to be semi-infinite with nonzero initial conditions. The concentration of each nuclide at the source is allowed to decay either continuously or according to some periodical fluctuations where both are subjected to either a step or band release mode. Two numerical examples related to the transport of 237Np and 245Cm in a five-layered system of fractured rock are used to verify these solutions with several well-established evaluation methods of Laplace inversion integrals in the real and complex domain. In addition, with respect to the model parameters, a comparison of the analytically derived local sensitivities for the concentration and cumulative mass of 237Np in the fracture with the ones obtained through a finite difference method of approximation is also reported. Both of these comparisons show excellent agreement. In spite of some limitations (i.e., assumptions of zero dispersion in the fracture and infinite matrix diffusion), the new features embedded in the reported solutions allow one to deal with commonly witnessed layered media above the water table, when groundwater flow is under steady-state conditions. In addition the residual concentrations in both fracture and rock, coupled with the realistic option of periodically fluctuating decaying source, are considered. These solutions are useful for verifying the accuracy of numerical codes designed to solve similar problems and, above all, cost-effective for performing sensitivity and uncertainty analyses of scenarios likely to be adopted in performance assessment investigations of potential nuclear waste repositories.
