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.
Conference Spotlight
2026 Nuclear Energy Conference & Expo (NECX)
August 24–27, 2026
Dallas, TX|Hilton Anatole
Latest Magazine Issues
Aug 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
September 2026
Nuclear Technology
Fusion Science and Technology
August 2026
Latest News
NRC issues draft EA/FONSI for Duane Arnold restart
Efforts by NextEra Energy to restart the Duane Arnold nuclear power plant as early as 2029 continue to move forward with the Nuclear Regulatory Commission's preliminary environmental assessment and determination that the restart would have no significant environmental impacts.
On Thursday, the NRC posted a draft environmental assessment and a finding of no significant impact for the Palo, Iowa, facility; the Federal Register notice was published on Monday. The Department of Energy’s Office of Energy Dominance Financing is a cooperating agency on the draft EA, as the DOE is considering providing financial assistance to the restart project.
R. Fischer, L. Giannone, J. Illerhaus, P. J. McCarthy, R. M. McDermott, ASDEX Upgrade Team
Fusion Science and Technology | Volume 76 | Number 8 | November 2020 | Pages 879-893
Technical Paper | doi.org/10.1080/15361055.2020.1820794
Articles are hosted by Taylor and Francis Online.
The results of transport modeling codes, e.g., GENE for the plasma core or SOLPS-ITER for the plasma edge, depend critically on reliable profile and equilibrium estimates. The propagation of uncertainties (UP) of input quantities to the results of modeling codes, e.g., power and particle exhaust and plasma stability, is frequently neglected because of the costs of running the codes as well as because of the missing uncertainty quantification of input quantities. The situation becomes even more cumbersome if profile gradients and their uncertainties are of major concern for transport analyses.
Two different techniques are presented to estimate profiles, profile gradients, their uncertainties, and candidate profiles for UP in modeling codes. Markov Chain Monte Carlo sampling of the posterior probability density of an integrated data analysis approach is applied to estimate electron density and temperature profiles. Nonstationary Gaussian process regression is applied to estimate ion temperature and angular velocity profiles. Both methods provide in a natural way profile gradients, profile logarithmic gradients, and their uncertainties.
Modeling codes benefit also from reliable equilibrium reconstructions and quantification of the uncertainty of various equilibrium parameters. For the analysis of diagnostics data, the position and uncertainty of flux surfaces as well as of the magnetic axis are important. For plasma transport and stability codes, the estimation of uncertainties of current and q-profiles is presented. For plasma edge codes the position of the separatrix contour and its uncertainty at various poloidal positions is of primary interest especially if steep profile gradients are present. Examples of uncertainties and their sources in magnetic scalar quantities, profiles, and separatrix contours are shown.