Critical density iteration
set iter nuc CYCLES KEFF NZAI ZAI1 ZAI2 ... ZAINZAI [ NMAT MAT1 MAT2 ... MAXNMAT ]
|CYCLES||: number of additional inactive cycles to run for the convergence of the iteration|
|KEFF||: target k-eff for the iteration|
|NZAI||: number of different nuclides (ZAI) included in the iteration|
|ZAIi||: the ZAI (e.g. 50100 for boron 10 ground state) of the nuclide to be included in the iteration|
|NMAT||: number of different materials included in the iteration (optional parameter)|
|MATi||: the name of the material to be included in the iteration|
- If a list of materials is not given, all materials that contain the included nuclides are included in the iteration.
- The initial concentration of the nuclides to be iterated should be larger than zero.
- The critical concentration iteration currently only works for nuclides that have a reactivity effect mainly through neutron absorption. Specifically, critical concentrations of fissile, moderating or reflecting nuclides cannot be iterated using this card.
An output variable ITER_NUC_FACTOR is included in the main [INPUT]_res.m results file. The output variable gives the mean multiplicative scaling factor applied to atomic density of the iterated nuclides to achieve a critical system.
If the batch history recording is set on (see set his) the [INPUT]_his[STEP].m history output file will contain batch-wise estimates for the scaling factor, which can be used to ensure the convergence of the scaling factor during the inactive cycles.
Serpent will first execute the inactive cycles