This paper presents evaluation of the atmospheric dispersion models DIPCOT and RIMPUFF which are incorporated for
operational use in Decision Support Systems for nuclear emergencies. The evaluation is performed through comparisons of model results
with real-scale measurements of gamma radiation dose rates in air obtained during the routine operation of the HIFAR Research Reactor
located in Sydney, Australia. The area surrounding the reactor is characterized by moderately complicated topography and varying land
cover. A total of 16 days have been computationally simulated, covering all atmospheric stability conditions. Qualitative and quantitative
model evaluation is carried out, using comparisons of paired in space and time calculated and measured gamma dose rates, statistical indices,
scatter plots, and contour plots. The models performance is satisfactory for a number of cases, while for others the performance is poor. This
can be attributed to a number of factors, mainly uncertainties in the prediction of meteorological conditions
