29. 



so that the waste was pumped into the crib and seeped into the soil. 

 Considerable safety factors have been added to limit activity seep- 

 age. Over a hundred wells were drilled for monitoring plants, soil, 

 and the underground regions. 



The cribs under construction are filled with rock, and gravel 

 of varying sizes, and then a waterproof paper covered with a topping 

 of soil. The waste is discharged into the central zone. The rock 

 and gravel fill is simply a cheap way to maintain a cavern; timbering 

 is costlier. 



CHAIRMAN HESS: Are there two long-life elements going into 

 the cribs in any appreciable amount? 



DR. CHRISTY: No, not in any appreciable amount. 



MR. LINDSEY: I would like to elucidate this a little more. 

 Those fission products that do go overboard have this column of soil, 

 250 or 300 feet high, to filter through before they get to the water 

 table, and the tests that we have run indicate that this soil has very 

 good absorption properties for picking out all the elements remaining. 

 The crib is used until the monitoring picks up the first trace of the 

 first salt coming through in the water table; the use of that crib is 

 then discontinued. In some cases a concrete cap is put on top of the 

 crib area so no surface water can percolate down through this column 

 of soil to absorb fission products. 



At Hanford we have a deep column of soil with excellent absorp- 

 tion qualities and we can dispose therefore of large quantities of low 

 level waste as a routine procedure. What we need now is a process 

 which will dispose of the high level wastes, and that will remove the 

 elements that have long life, and remove those that are not absorbed 

 readily by the soil. 



DR . HENRY C . THOMAS: Have any studies been made of the 

 distribution of the absorbed elements under the crib? To do this, 

 would you have to sample every six feet and determine the change in 

 the composition of the material? 



MR. LINDSEY: I would like Mr. Lieberman to answer that. 



MR. JOSEPH A. LIEBERMAN: There has been a little of that 

 done. We are dealing only with the low level waste from which the 



