Abstract The LEPRICON adjustment procedure involves combining both differential and integral data, including covariances and sensitivities, in such a way that calculated spectral fluences at important locations within a pressure vessel of an operating PWR can be adjusted with significantly reduced uncertainties. The procedure allows simultaneous combination of integral dosimetry measurements performed at a reactor surveillance location with measurements performed in geometrically simpler benchmark facilities. An application of this technique is given to an existing PWR, and the results consistently indicate a need for significant (∼ 8%) adjustments in the total inelastic cross section of iron in the region between 3 and 8 MeV using cross sections and covariances from ENDF/B-V. Dosimetry cross sections were taken mainly from a revised version of ENDF/B-V and were found to require relatively small adjustments. Covariances of the spectral fluences are reduced by factors lying between two and four.