570 



- 6 - 



In the areas currently under study, the ocean is four to six 

 kilometers — or about three miles — deep and the bottom consists 

 of fine-grained clay sediments with an average thickness of 400 

 meters (1300 feet) overlaying the basement rock. These clay - 

 sediments have high sorption coefficients for some 

 radionuclides. 



In addition, while the ocean water is not considered a primary 



barrier to radionuclide transport, it would provide additional 



safety since it provides a barrier to accidental or intentional 



intrusion, and acts as a dispersal medium for decayed 



radionuclides which may eventually reach the water/sediments 

 level. 



Subseabed Disposal Program 



Background 



The Department of Energy and its predecessor agencies have been 

 conducting research into the subseabed alternative for nuclear 

 waste disposal since 1974. 



To coordinate the international assessment of seabed disposal, 

 in 1976 a Seabed Working Group (SWG) was established under the 

 auspices of the Nuclear Energy Agency of the Organization for 

 Economic Cooperation and Development (NEA/OECD). The SWG has 

 conducted annual meetings since that time. 



