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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.
William T. Sha, Alan E. Waltar
Nuclear Science and Engineering | Volume 44 | Number 2 | May 1971 | Pages 135-156
Technical Paper | doi.org/10.13182/NSE71-A19663
Articles are hosted by Taylor and Francis Online.
A two-dimensional (R - Z) integral model for characterizing fast reactor excursions from accident inception through core disassembly is presented. For predisassembly calculations, a Eulerian geometric model is used and multichannel heat-transfer computations are performed. Reactivity feedback due to Doppler broadening, coolant density change and voiding, and fuel movement are taken into account. A Lagrangian coordinate system is used in the disassembly phase, wherein the neutronics balance consists of Doppler broadening and material motion. A unique feature of the model is the ability to accommodate a pointwise Energy-Density-Dependent Equation-of-State according to the local sodium inventory that actually exists at the time of disassembly. By providing a consistent basis for establishing the effective reactivity ramp rate, Doppler coefficient, appropriate Equation-of-State, and temperature distribution at the start of core disassembly, much of the arbitrariness normally associated with large accident analyses can be removed. For most accident analyses, this model predicts a significantly lower energy yield during a superprompt critical nuclear excursion than would be computed by using the conventional modified Bethe-Tait analysis.