An irradiation exposure profile was calculated and subsequent experimental measurements using nondestructive dosimetry procedures were obtained for the reactor pressure vessel of the Portable Medium Power Plant (PM-2A). Near the core centerplane at the inner edge of the vessel, the maximum calculated exposure is 1.6 × 1019 n ≥ 1 MeV/cm2 and the maximum calculated activity from the 54Fe (n,p) 54Mn reaction is 1.9 × 107 dis/(cm3 sec) as of July 9, 1965. The average of calculated-to-measured 54Mn activity for 25 azimuthal locations at the core centerplane is 1.05. This agreement is within the uncertainties of either the calculated or experimental results.