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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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NNSA awards BWXT $1.5B defense fuels contract
The Department of Energy’s National Nuclear Security Administration has awarded BWX Technologies a contract valued at $1.5 billion to build a Domestic Uranium Enrichment Centrifuge Experiment (DUECE) pilot plant in Tennessee in support of the administration’s efforts to build out a domestic supply of unobligated enriched uranium for defense-related nuclear fuel.
Wilmer A. Coloma, Antonella L. Costa, Claubia Pereira, Clarysson A. M. da Silva
Nuclear Technology | Volume 206 | Number 4 | April 2020 | Pages 554-564
Technical Paper | doi.org/10.1080/00295450.2019.1662668
Articles are hosted by Taylor and Francis Online.
Analysis of the power time series evolution is used to investigate a stable or unstable process after the disturbance in a light water reactor of the boiling water reactor (BWR) type. Several different methodologies are currently used and the uncertainties of the various approaches are in some cases very different. In this work, the time series model known as the Autoregressive Moving Average model was used to calculate the decay ratio (DR), and the natural frequency (NF) due to power oscillations in a BWR. The method consists of locating the appropriate dominant pole of the transfer function. The autoregressive methods are quite often used to study the stability of BWR reactors. In this work the Box-Cox transformation is implemented to stabilize the variances of the power signals in order to maintain the linear assumptions that the calculation of DR and NF needs; that is, to correct biases in the distribution of errors to stabilize the variance and mainly so that the signal approaches a linear behavior. The MATLAB code was used for this purpose. This work also presents a nonlinear analysis of the power series, determining the values of the largest Lyapunov exponents with Rosenstein’s algorithm in order to analyze the stability of the system. The results of the DR and NF calculated by the used methodology are very close to the values obtained in the benchmark.