Stirring system for radioactive waste water storage tank.

A stirring system for 100-m(3) radioactive liquid waste tanks was constructed to unify radioactive concentrations in the tank. The stirring system is effective in certifying that the radioactive concentrations in the tanks are less than the legal limits before they are drained away as waste liquid. This system is composed of discharge units, pipe lines, and a controller. The performance of the system was assessed by comparing the calculated red ink and 32P concentrations with those monitored at six locations in the tanks. The concentration reached equilibrium after stirring 60 to 120 min with discharge units equipped with six fixed openings configured in differing directions. Residual chlorine in city water used for dilution occasionally bleached the red ink and reduced its concentration. The adsorption of 32P by slime on the walls of the tanks storing actual waste water lowered the equilibrium concentration.