Principles of the expression of uncertainty in measurements are briefly rev
iewed and special aspects of the uncertainty quantification in NAA are disc
ussed in detail regarding the relative and k(0)-standardization in both mod
es of the technique, i.e., INAA and RNAA A survey of uncertainty sources is
presented and calculation of the combined uncertainty is demonstrated by a
n example of manganese determination in biological material by RNAA.