[en] Monte Carlo analysis of a Time-of-Flight (TOF) experiment can be utilized to examine the accuracy of nuclear cross section data. Accurate determination of this data is paramount in characterization of reactor lifetime. We have developed a methodology to examine the impact of modifying the current cross section libraries available in ENDF-6 format (1) where deficiencies may exist, and have shown that this methodology may be an effective methodology for examining the accuracy of nuclear cross section data. The new methodology has been applied to the iron scattering cross sections, and the use of the revised cross sections suggests that reactor pressure vessel fluence may be underestimated. (authors)