Radiation measurements were made during recent high power, high neutron yield experiments, and used to calibrate the neutronics simulation of the radiation shielding system. The results indicate that the present radiation shielding is more effective than predicted by the initial design estimates. This is attributed to the effects of changes in the experimental configuration since the initial design and to the design margin included to accommodate initial uncertainties in material properties and distributions. With the present radiation shielding, the production of 5 × 1020 D-T neutrons/yr will result in a total annual dose equivalent at the PPPL property line of less than the 10 mrem/yr design objective.