Aerodynamic effects of the EBR-II containment vessel complex on effluent concentration

Dispersion measurements of a tracer, uranine dye in solution, were made around a reactor complex to 600 meters from release point, in stable and unstable atmospheres. The tracer was released from the northeast side of the EBR-II reactor containment vessel and sampled at the one meter level by 90 high-volume air samplers. Some 24 releases for 30-minute periods were analyzed. Techniques of dispersal, collection and analysis of the tracer are included. Meteorological measurements during tests included vertical and horizontal wind direction and velocity fluctuations at the six meter level at one upwind and several downwind locations and vertical temperatures at several levels on a 74 meter tower. It was found that the increase of the product of vertical and horizontal turbulence downwind of the structures over that in open terrain could exceed a factor of 15 at 100 meter downwind for 5-minute periods and averaged a factor of 5.0 for 30-minute periods. A counteracting measure is the factor of two decrease of the wind speed in the wake cavity of the structure. The average maximum arc concentrations were found to be proportional to the -0.6 power of distance downwind. No simple power law relationship was found for σy with distance downwind. Predictions of σy from σθ via the empirical relationship σy =0.035σθX0.87 were excellent. Several formulae were tested for calculating the diffusion in the wake of an obstacle. (author)