95. 



sealing of any pit. Adsorption by the clay minerals 

 seems to show signs of promise, but in the ground this 

 reaction is reversible and therefore not reliable as a 

 "sealing" method. Long monitoring of low-level wastes 

 may give valuable data on these problems. 



(3) Conclusions. Disposal in shale pits is too risky in our 

 present state of knowledge. The method, however, may 

 have promise, and continued research on adsorption and 

 sealers is recommended. 



(4) Significant parts of the discussion leading to above sum- 

 mary. 



If the material is placed in shale pits, deposition of 

 solids will occur at the bottom and produce sealing there. 

 The clear supernatant with some high radioactivity will 

 pass out the sides. 



Can we assume pH control? 



Only at great cost and increase in volume. (ORNL) 



The question has been raised of the effect of zirconium 

 and the possibility of zirconium recovery. 



Zirconium is tetravalent and has a high replacement 

 value for other adsorbed ions and would displace the 

 strontium. 



Couldn't we use nonradioactive material to seal and 

 then place in it the radioactive material? Then the mem- 

 brane would be self-sealing. 



Ideal conditions are being assumed. There is a great 

 variation in rocks in their cementing abilities to the ex- 

 tent that probably no one would place his stamp of ap- 

 proval on it. 



If the shale is thick and stable it might be a good 

 gamble, since it could be monitored. 



Sealing depends on the interaction with the rock. Dilu- 

 tion may damage the gel. 



