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 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
May 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
June 2026
Nuclear Technology
Fusion Science and Technology
Latest News
Getting back to yes: A local perspective on decommissioning, restart, and responsibility
For 45 years, Duane Arnold Energy Center operated in Linn County, Ia., near the town of Palo and just northwest of Cedar Rapids. The facility, owned by NextEra Energy, was the only nuclear power plant in the state.
In August 2020, a historic derecho swept across eastern Iowa with winds approaching 140 miles per hour. Damage to the plant’s cooling towers accelerated a shutdown that had already been planned, and the facility entered decommissioning soon after, with its fuel removed in October of that year. Iowa’s only nuclear plant had gone off line.
Today the national energy landscape looks very different than it did just six short years ago. Electricity demand is rising rapidly as data centers, artificial intelligence infrastructure, advanced manufacturing, and electrification expand across the country. Reliable, carbon-free baseload power has become increasingly valuable. In that context, Linn County has approved the rezoning necessary to support the recommissioning and restart of Duane Arnold and is actively supporting NextEra’s efforts to secure the remaining state and federal approvals.
Eric Sykes (NWMO), Stefano D. Normani (Univ of Waterloo), Lorrie Fava, Darren Janeczek (MIRARCO)
Proceedings | 16th International High-Level Radioactive Waste Management Conference (IHLRWM 2017) | Charlotte, NC, April 9-13, 2017 | Pages 859-866
The ability to conceptualize and represent uncertainty in the geometry, dimensionality, and parameterization of key geosphere processes is a necessary element in the development of credible geosphere models. In crystalline rock typical of the Canadian Shield, these three-dimensional geosphere models are principally composed of discrete fracture network models and numerical groundwater models, which when combined, form an integrated platform for the on-going synthesis of geosphere data.
Fracture network modelling involves using three-dimensional, geostatistical tools for creating realistic, structurally possible models of fracture zone networks within a geosphere that are based on field data. The fracture network models, by honouring and incorporating available site data, allow for a greater understanding of the geometry and interconnectivity of the fractures in a quantitative manner. MoFrac, based upon the legacy fracture network modelling software FXSIM3D, is a new fracture network modelling tool capable of generating fracture network geometry composed of both stochastic and deterministic features.
The groundwater modelling methodologies applied within this project were developed and tested within the NWMO Geoscience Technical R&D program, and provide a numerical framework to assemble and integrate geosphere data including topography, surface water features, fracture networks, and hydraulic conductivities. These geosphere data, when synthesized into a three-dimensional geosphere conceptual model, form the basis for the integrated groundwater systems models. These models provide a quantitative assessment of suitability and facilitate a full understanding of the influences of geosphere factors such as topography, surface water features, and fracture zone geometry and interconnectedness. The numerical groundwater modelling software HGS was employed for this study.
A representative sub-regional scale test case based upon Canadian Shield data was used in order to demonstrate the modelling workflow. Performance measures include groundwater heads, velocity magnitudes, Mean Life Expectancies (MLEs), and depth of recharge of a surficial tracer.
