ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Jun 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
Fusion Science and Technology
July 2025
Latest News
The U.S. Million Person Study of Low-Dose-Rate Health Effects
There is a critical knowledge gap regarding the health consequences of exposure to radiation received gradually over time. While there is a plethora of studies on the risks of adverse outcomes from both acute and high-dose exposures, including the landmark study of atomic bomb survivors, these are not characteristic of the chronic exposure to low-dose radiation encountered in occupational and public settings. In addition, smaller cohorts have limited numbers leading to reduced statistical power.
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.