Abstract A simple model of thermal-hydraulic feedback for the neutronic analysis of a PWR core was developed and implemented into an overall calculational system. A series of numerical experiments were carried out to establish the coefficients of the cross-section adjustment formulas. A benchmark comparison calculations of a ZION-2 (Impink et al., 1979) first-cycle demonstrated the validity of the model and overall improvements of the quality of the neutronic analysis. For PWRs the thermal-hydraulic feedback has a second-order effect on the results of the neutronic analysis, therefore application of the simplified models generate reasonably accurate results. Actual implementation of the model into the BGUCORE calculational system (Galperin et al., 1985) is described and demonstrated.