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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.
L. Eric Smith, Naeem M. Abdurrahman
Nuclear Technology | Volume 140 | Number 3 | December 2002 | Pages 328-349
Technical Paper | Radiation Measurements and Instrumentation | doi.org/10.13182/NT02-A3343
Articles are hosted by Taylor and Francis Online.
A Monte Carlo study of the neutron slowing-down spectrometry technique for measuring fissile isotopic content in irradiated fuel has been completed. The neutron spectrometer system is characterized in terms of design, slowing-down time relation, isotopic response functions, and assay signals. The nonlinear effect of interrogating neutron self-shielding for a high fissile content fuel is compared to the same parameter for a low fissile content fuel. Simulated assays of 23 different fuel assemblies with a broad range of total fissile mass content (1.3 to 83 wt%) and fissile isotopic ratios are performed and analyzed using two different methods: a linear system model using a least-squares regression analysis and a radial basis neural network. Mean errors using the linear system model for the 23 different fuel types were approximately 20% for 235U and 43% for total plutonium. The radial basis neural network assay signal solutions showed promising results, considerably better than the linear model: 4.9% for 235U, 5.4% for total plutonium, and 0.5% for total fissile content.