# Keyword:ERROR

ERROR nerror
parent(i) daughter(i) ermat(i) i=1,nerror

This keyword inputs the number nerror of reactions and the identifiers of the parent and daughter of each reaction and (optionally) the fractional error of the reaction cross section. In versions of FISPACT prior to 3.0, the user had to input a value of the fractional error, but this is now available from the EAF or ENDF uncertainty files.

If data from the uncertainty le are to be used then ermat must be set to -1. If the keyword is absent, then all ermat values default to -1. Note that if no uncertainty data exist in the library then the fractional error must be input; using -1 will cause an error message to be printed. This keyword should only be used following the keyword SENSITIVITY to give the error in the number of atoms of a nuclide due to the speci ed reactions; for routine calculations the uncertainty calculations are automatically performed by a simplified method. Parent-daughter pairs listed must also appear in the SENSITIVITY list.

An example of this keyword is:

Example usage:

< -- Control phase -- >
...
FISPACT
* Title of the simulation
< -- Initial phase -- >
...
ERROR 2
Li7 Li8 -1.0
Be9 He6 -1.0
...
< -- Inventory phase -- >
...


In this case the two reactions specified by these parent-daughter pairs are considered, with the uncertainty being obtained from the nuclear data uncertainty files.