This work presents results of computer simulation of two experiments which aim at measuring the threshold activation reaction rates in 12C, 19F, 27Al, 59Co, 63Cu, 65Cu, 64Zn, 93Nb, 115In, 169Tm, 181Ta, 197Au, and thin samples placed inside and outside a 0.8 GeV proton-irradiated 4-cm thick W target and a 92-cm-thick W-Na composite target of 15 cm diameter both. In total, more than 1000 values of activation reaction were determined in both the experiments. The measured reaction rates were compared with the rates simulated by the LAHET code with the use of several nuclear databases for the respective excitation functions, namely, MENDL2 together with MENDL2P for cross sections of protons and neutrons up to 100 MeV, and with the recently developed IEAF-2001 that provides neutron cross sections up to 150 MeV. A comparison of simulation-to-experiment agreement obtained with MENDL2 and IEAF-2001 is presented. The agreement between simulation and experiment has been found general satisfactory for both databases. However, further studies should be done to improve the simulation of production of secondary protons and high-energy neutrons, as well as the high-energy neutron elastic scattering. Our results allow to conclude about the reliability of the transport codes and databases used to simulate the accelerator driven systems (ADS), particularly with Na-cooled W targets. High-energy threshold excitation functions to be used in the activation-based unfolding of neutron spectra inside the ADS can also be inferred from these results.