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ANS Student Conference 2025
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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.
Weston M. Stacey, Jr.
Nuclear Science and Engineering | Volume 36 | Number 3 | June 1969 | Pages 389-401
Technical Paper | doi.org/10.13182/NSE69-A18736
Articles are hosted by Taylor and Francis Online.
A stochastic kinetic theory for space- and energy-dependent, zero power, nuclear reactor models is constructed from a last collision probability argument. The space and energy domains are partitioned into discrete cells. Equations are developed for the probabilities for transitions among the possible states of the reactor, and an equation is obtained for the probability generating function for these transition probabilities. Equations for the mean values, variances, covariances and correlation functions of the neutron and precursor distributions are derived. The stochastic distributions of neutrons and precursors are found to be space- and energy-dependent in subcritical reactors, but to attain a space- and energy- independent asymptotic form in supercritical reactors. The asymptotic distribution in a supercritical reactor is identical for the neutron and precursor distributions, and depends upon the manner in which the reactor is made supercritical. A method for applying the theory to low-source start-up calculations is suggested. The influence of spatial stochastic effects upon such calculations is demonstrated.