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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.
Pinky Batheja, Feroz Ahmed, L. S. Kothari, Otohiko Aizawa
Nuclear Science and Engineering | Volume 89 | Number 4 | April 1985 | Pages 366-380
Technical Note | doi.org/10.13182/NSE85-A18629
Articles are hosted by Taylor and Francis Online.
Using diffusion theory and the eigenfunction expansion method, a detailed time-dependent study of fast neutrons has been made for three iron assemblies: infinite, 1 m3, and 0.5 m3. Various results have been obtained by taking two different source energies, namely, 14.47 and 1.0076 MeV. All the calculations have been carried out using the 50-group cross-section set of Ahmed et al. For the 1.0076-MeV source, (a) the time-dependent spectra exhibit two distinct peaks up to ∼50 ns, (b) energy variation of the mean slowing down time shows “anomalous” behavior similar to that observed by Bey non et al., and (c) the most probable time has two different values for some energy groups below ∼240 keV, in conformity with the results of White et al. The double values of (except for the 40th and 41st groups) and the “anomalous” behavior observed in cease when we take the source energy to be 14.47 MeV. Further, for all values of energy Ei, the values of both and decrease as the size of the assembly is reduced. It has been shown that in the two larger assemblies, pseudoasymptotic conditions are established in certain time intervals. It was determined that some energy groups tend to cluster and decay with the same decay constant after a certain time.