This keyword is used for fine-tuning of the pathways and uncertainty calculations. If it is present then the pathways and uncertainty calculations do a look-ahead over the entire cooling phase and add any dominant nuclides that appear in the late-time dominant nuclide lists to the list of target nuclides created at the ZERO time for use in the pathways calculation.

This keyword should be used with care as it may lead to slow calculations or even code failure through heap exhaustion because of large numbers of target nuclides in the pathways calculation. If this is a problem then the keyword PATHRESET provides an alternative approach. This keyword requires UNCERTAINTY to be included in the input.

Example usage:

< -- Control phase -- >
...
FISPACT
* Title of the simulation
< -- Initial phase -- >
...
UNCERTAINTY 2
...
< -- Inventory phase -- >
...