Evaporation of the reactor wastes is accomplished in a 
two stage evaporating system. An over-all decontamination factor 
of the order of 108 is achieved, The waste is evaporated to 35% 
solids; beyond this point certain materials in the slurry residue 
would start to crystallize. The residue is then jetted to one 
of a group of holding tanks. 
There are "General Purpose Evaporators" for various low 
activity wastes, including those from the laboratories. A special 
evaporator is provided to handle the higher level laboratory 
wastes. 
Tank Storage 
The evaporator residue is received in 750,000 gallon 
tanks constructed of steel and concrete. The tanks are equipped 
with cooling coils to dissipate radioactive decay heat. An air 
space separates the steel wall from the outer shell of reinforced 
concrete. The steel tank rests on a saucer-like bottom which 
would catch and allow detection of any leakage from the tank 
into the annular air space. All of the tanks are buried under- 
ground for effective shielding. Gas filtering devices on the 
tank vents prevent radioactive contamination of the atmosphere, 
Clay 100 to 200 feet thick underlies the storage tank 
area, Laboratory tests have show this clay to be a very good 
ion exchange medium. It therefore provides a factor of safety 
in case of damage to the tanks. Monitoring wells surround the 
area, warning of any leakage outward from the storage area. 
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