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Division Spotlight
Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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!
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Latest News
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
M. Gentili, B. Fontaine, G. Rimpault
Nuclear Technology | Volume 192 | Number 1 | October 2015 | Pages 11-24
Technical Paper | Fission Reactors | doi.org/10.13182/NT14-123
Articles are hosted by Taylor and Francis Online.
Fast reactor designs are currently being revisited aiming at having a consolidated safety dossier. In that frame, studying any perturbation of nominal operating condition is mandatory.
Among different initiators, particular attention is being paid to reactivity insertion due to core assembly bowing and deformation and induced lattice readjustments as a consequence of events such as earthquakes.
In this study, a deterministic calculation scheme based on the mesh projection method has been used in order to evaluate the reactivity changes occurring in a deformed sodium fast reactor core.
With the microscopic cross sections calculated by ECCO, full three-dimensional core calculations are being conducted with ERANOS (DIF3D), VARIANT, and SNATCH to solve neutron transport equations in either diffusion, nodal variational, or Sn transport approximations.
A simple analytical model based on perturbation theory has been developed to identify the main phenomena leading to changes in the core reactivity. Reactivity changes induced by small deformations can be estimated as a summation of reactivity perturbations of individual subassemblies.
The results obtained with this method have been checked by comparing them to those obtained with Monte Carlo simulations. A good agreement is being found allowing the use of this method in realistic problems with significant computer resource reduction.
The different contributions to the reactivity changes confirm the results of the analytical model.
