available at a number of other sites. 



The second most promising method seems to be in forming a 

 silicate brick or slag which would hold all elements of the waste in 

 virtually insoluble blocks. These could be stored in sheds on the 

 surface in arid areas or in dry mines. 



Separation of the Cs and Sr isotopes from the waste and their 

 storage in small packages or surface tanks would of course greatly 

 simplify the general problem of waste disposal. Research on the 

 feasibility of such separation should be pushed. 



Finally, disposal of waste in porous media such as sandstones 

 at comparatively great depth may eventually be possible. Unlike 

 oil, the waste would be denser than the normal saline water contained 

 in such beds provided the heat generated by radioactive decay after 

 emplacement is not sufficient to reverse the density relationship. 

 Instead of concentrating in and being immobilized in tops of anticlines 

 it would sink to floors of synclines. Deep synclines with closure 

 would be preferred as disposal structures inasmuch as they would 

 largely immobilize the waste if it was not allowed to become too hot. 

 The great difficulty with this potential method is that the character 

 of the waste fluid would have to be drastically changed to permit it to 

 disperse in the porous medium without clogging the pore space.— 

 Acid aluminum nitrate wastes would almost certainly form a gel -like 

 substance if pumped into a sandstone. Extraction of the radioactive 

 elements from the much larger bulk of aluminum nitrate appears at 

 present to be a prohibitively expensive process. If processes were 

 changed to produce waste without this unfavorable character deep 

 disposal would become much more reasonable. The possibility that 

 great dilution of aluminum nitrate waste fluid might alleviate pore 

 space clogging should be investigated though it does not seem likely 

 that the problem will be solved in this way. Folded rocks containing 

 porous beds in which suitable structures could be located are widely 

 distributed in the United States. 



The above remarks indicate the most promising avenues on 

 which research should be pressed. Besides these, it is necessary 

 to train a number of geologists in the attributes of the wastes and the 

 possible solution of the problems of their disposal. Geological in- 

 vestigation of a large number of potential sites for processing plants 



— Edwin Roedder (USGS) (1956) Disposal of high aluminum radioac- 

 tive waste solutions by injection into aquifers. 



