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Aerospace Nuclear Science & Technology
Organized to promote the advancement of knowledge in the use of nuclear science and technologies in the aerospace application. Specialized nuclear-based technologies and applications are needed to advance the state-of-the-art in aerospace design, engineering and operations to explore planetary bodies in our solar system and beyond, plus enhance the safety of air travel, especially high speed air travel. Areas of interest will include but are not limited to the creation of nuclear-based power and propulsion systems, multifunctional materials to protect humans and electronic components from atmospheric, space, and nuclear power system radiation, human factor strategies for the safety and reliable operation of nuclear power and propulsion plants by non-specialized personnel and more.
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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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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.
Deokjung Lee
Nuclear Science and Engineering | Volume 174 | Number 3 | July 2013 | Pages 300-317
Technical Paper | doi.org/10.13182/NSE12-27
Articles are hosted by Taylor and Francis Online.
The impact of the dynamic condensation of energy groups on the convergence characteristics of the coarse mesh finite difference (CMFD) algorithm has been analyzed within the framework of two-group (2-G) one-node (1-N) local kernel (CMFD1N) and one-group or 2-G global CMFD formulations. Three algorithms were analyzed by the method of linearizing the nonlinear algorithms and applying Fourier analysis to the linearized algorithms: partial current sweep (PCS), CMFD1N, and CMFD1N with dynamic condensation (CMFD1N-DC). Because of the dynamic condensation, the spectral radius of the CMFD1N-DC algorithm is influenced by the other two algorithms; i.e., it shows a similar behavior to the PCS algorithm for small mesh sizes and a similar behavior to the CMFD1N algorithm for large mesh sizes. From the theoretical derivation, it was shown that the spectral radius is determined by the combination of partial current spectrum update in the local PCS kernel and the current correction factor update in the global CMFD. Specifically, the convergence properties of the CMFD1N-DC algorithm follow those of the PCS algorithm for small mesh sizes since the energy spectrum is only updated in the local kernel. It was also observed that the relaxation parameter for the CMFD1N-DC algorithm needs to be determined with the fast group cross-section data because of the dynamic condensation.
