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NRC approves TerraPower construction permit
Today, the Nuclear Regulatory Commission announced that it has approved TerraPower’s construction permit application for Kemmerer Unit 1, the company’s first deployment of Natrium, its flagship sodium fast reactor.
This approval is a significant milestone on three fronts. For TerraPower, it represents another step forward in demonstrating its technology. For the Department of Energy, it reflects progress (despite delays) for the Advanced Reactor Demonstration Program (ARDP). For the NRC, it is the first approval granted to a commercial reactor in nearly a decade—and the first approval of a commercial non–light water reactor in more than 40 years.
Carol Braester, Roger Thunvik
Nuclear Technology | Volume 79 | Number 3 | December 1987 | Pages 371-376
Technical Paper | Heat Transfer and Fluid Flow | doi.org/10.13182/NT87-A34026
Articles are hosted by Taylor and Francis Online.
An analysis of the confidence of flow solutions for stochastically generated hard rock formations study was carried out with the aid of a simplified synthetic model. The formation was conceptualized as a fracture network with a known geometric structure intersecting an impervious mass rock while fracture permeability was considered a stochastic process. Safety analysis of radioactive waste repositories includes prediction of travel times of possibly contaminated water particles from the repository to the biosphere. While such calculations require that rock properties, such as permeability, be known over the entire flow domain, only limited information is available in practice, and interpolation methods are called for. An a priori model was constructed as a first step, with fracture permeabilities generated according to a given probability distribution; this a priori model was considered the “true” formation. In a second step, a limited amount of information, similar to that obtained in reality from boreholes, was used to construct a conditioned-by-measurement model. Identical flow tests were performed on formations represented by the two models, and the flow rate ratios resulting from these tests served as the measure of confidence of the stochastically generated formation. Results with a two-dimensional flow domain and a particular data set, show uncertainty values between 46 and 61%, corresponding to borehole spacing from 10 to 100 m intersecting 11 and 2%, respectively, of the total number of fractures in the network. Results with a three-dimensional flow domain show uncertainty values between 17 and 50%, corresponding to borehole spacing from 25 to 100 m intersecting 0.2 and 0.02%, respectively, of the total number of fractures. Calculations indicate that stochastically generated formation properties may lead to nonconservative results. This suggests that overestimation methods such as using permeability values obtained from an envelope passing through the highest values should be employed in order to obtain conservative results.
