30. 



cesium and strontium has not been removed completely. The ferro- 

 cynide method is excellent, it is relatively new, and is more effec- 

 tive with cesium and strontium than other methods. The process and 

 procedure used in disposing of the supernatants containing the rest 

 of the fission products is based on laboratory experiments: soil col- 

 umns are made up to simulate the soil profile and then the actual 

 waste is passed through; from this is determined how much waste can 

 be passed through the column before a contaminant will "break 

 through" at the specific deposits under consideration. Strontium is 

 usually the critical element. Let's say five column volumes of this 

 waste are in the laboratory column out in the field. We will put in the 

 equivalent say, of two columns of waste. (These are not necessarily 

 the figures or proportions actually used.) I understand there is some 

 strontium put in the ground in Hanford, however, no strontium has 

 been detected in the ground water. If, by chance, some contaminant 

 passed through the exchange columns and down to ground water, its 

 half-life must have been short and by the time it traveled to the 

 Columbia River its effectiveness must have disappeared. 



To answer your question specifically, there is laboratory infor- 

 mation on the point you make, but in the field, it is very difficult to 

 get comparable data. It is more a case of detecting activity at differ- 

 ent levels rather than getting the spectrum. Ruthenium is expected to 

 be at the bottom, strontium close to the top, and the others appear 

 between; this distribution has been established as a result of laboratory 

 work. 



DR. DAVID T. GRIGGS: There has been mention of longer life 

 elements: does that refer to the fission products that were mentioned? 



DR. CHRISTY: Consider plutonium. 



DR. GRIGGS: Are there any longer life fission products? 



DR. CHRISTY: Plutonium is of most concern. 



DR. GRIGGS: Will that information be available? 



DR. CULLER: Sure. There are a lot of them. The list is quite 

 long. 



DR. CHRISTY: Other chemicals present in these wastes, in ad- 

 dition to the fission products, are the following: 



