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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.
Isao Murata, Detlef Filges, Frank Goldenbaum
Nuclear Science and Engineering | Volume 159 | Number 3 | July 2008 | Pages 273-283
Technical Paper | doi.org/10.13182/NSE159-273
Articles are hosted by Taylor and Francis Online.
A new importance estimation method, which is based on the adjoint function definition, has been proposed especially for the weight window (WW) technique of MCNP, which is well known as one of the most powerful variance-reduction techniques in Monte Carlo codes. The method employs the scattering point base importance estimation, unlike the WW generator (WWG) of MCNP for the point detector function. Every scattering point has an adjoint contribution to the detector, with which a space-, energy-, and angle-dependent importance for WW could be estimated. From the numerical test calculations, the basic performance was confirmed to be better than WWG by comparing figure-of-merit values. It would be expected that the performance of WWG would be well improved by using the present method instead of the current MCNP routine of accumulating the detector contribution for the F5 tally. The presently proposed method would be a strong tool to estimate the importance applicable to various variance-reduction techniques in Monte Carlo codes.