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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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.
Jeffrey A. Favorite
Nuclear Science and Engineering | Volume 155 | Number 2 | February 2007 | Pages 321-329
Technical Paper | Mathematics and Computation, Supercomputing, Reactor Physics and Nuclear and Biological Applications | doi.org/10.13182/NSE07-A2666
Articles are hosted by Taylor and Francis Online.
Standard variational estimates for perturbations in inhomogeneous transport problems were applied to internal-interface perturbations in coupled neutron-photon problems. Absolute gamma-ray line leakages and ratios of line leakages were the quantities of interest. Gamma-ray spectroscopy using the deterministic multigroup discrete-ordinates code PARTISN was accomplished with a 130-group neutron library and a 120-group photon library with narrow bins centered around gamma lines of interest. Perturbed integrals were evaluated using a volume and a surface formulation, and issues involving negative fluxes (required in the adjoint calculation for line ratios) were addressed. Numerical test problems used a 252Cf source surrounded by a material containing nitrogen and hydrogen; the thickness of this material was perturbed ±86%. The ratios of the 1.8848-, 2.2246-, and 5.2692-MeV thermal neutron capture lines were very well estimated using the variational estimates, even for macroscopic-size perturbations of internal interface locations; the volume-integral formulation for the perturbed integrals was generally more accurate than the surface-integral formulation for estimating ratios. For estimating absolute leakages, the Roussopolos functional in the surface-integral formulation was clearly superior when the gamma-producing shell was thickened, but it produced negative estimates when the shell was thinned.
