92 



(p. 5). In view of the severe adverse environmental impact that the ocean dumping 

 of municipal sewage sludge has caused in the ocean waters of the New York Bight, 

 this low priority is both suprising and disturbing. I would like to know the reason 

 for assigning sewage sludge dumping to a low priority in the Federal Plan. 



Answer. The national policy for the ocean dumping of sewage sludge is that it will 

 cease in 1981. Given the extensive research that has occurred over the last decade, 

 the local nature of the problem, and the current legislated policy, the interagency 

 committee members agreed that a low priority should be placed on the research 

 needs in this area. 



Questions From Mr. Pritchard and Answers 



Question 1. What work has been done on the criteria for the selection of sites for 

 sub-seabed nuclear waste disposal? 



Answer. Several years of DOE-sponsored work have been devoted to establishing 

 criteria for the selection of sites for sub-seabed nuclear disposal. The major criteria 

 are that: the sea floor chosen be of long-term stability; it be covered with a thick 

 layer of sediment; and it be at any abyssal depth. The best sites, therefore, would be 

 in abyssal hill regions at the center of tectonic plates, with a 5 to 100 meter 

 thickness of red clay sediment. 



Question 2. Is any work being done to map proposed sites? What type of mapping 

 and profiling will be done? 



Answer. Some work has been conducted using conventional echo sounders for 

 defining the surficial shape of the seafloor, and high energy sonic profilers for 

 subsurface structure. Finer scale mapping will have to be obtained over the sites, 

 when selected. 



Question 3. Based on the work up to this date on seabed disposal of radioactive 

 waste, are there any studies which conclude that seabed is not viable and we should 

 not conduct further studies? 



Answer. To our knowledge, five years of research have yielded no technical 

 reasons why seabed disposal should not be studied further, and considered as a 

 viable disposal option. 



Question 4- Has any work been conducted en the method of waste implementation 

 in the deep seabed in geologically inactive sites? 



Answer. Yes. The method currently being discussed is to use elongate conisters 

 that would penetrate the sea floor and bury themselves in the sediment. 



Other alternative strategies are being considered including free-fall penetration, 

 jet assist, and drilling. 



Question. 5. Would we have to develop new technology for the transportation and 

 disposal of radioactive wastes? 



Answer. New technology for the transportation and disposal of radioactive wastes 

 will in all probability need to be developed. This is of particular importance for the 

 deployment of the canisters so that penetration in the sediments can be achieved 

 safely and effectively. 



Question 6. Are there any methods of retrieving implanted waste canisters from 

 beneath the seabed if the need arises? 



Answer. To our knowledge there are no proven methods of retrieving implanted 

 waste canisters from beneath the seabed if the need arises. Such methods will need 

 to be devised if retrieval in the future is a consideration. 



Question 7. Does NOAA have the capability to monitor the entire disposal process 

 should sub-seabed disposal become a viable option? 



Answer. Yes, provided Class I ships can be dedicated when such disposal oper- 

 ations are taking place. Ships of that size are needed to tow devices that can 

 monitor the abyssal depths remotely. In situ sensors, which can be retrieved by 

 surface vessels, will also need to be used. 



Question 8. Do submersibles exist that can travel to the depths where disposal 

 might take place? 



Answer. The U.S. Navy's TRIESTE II is a manned-submersible that can work at 

 depths up to 6,00m. 



Question 9. Can the sediment withstand the high heat that nuclear waste gener- 

 ates? 



Answer. One of the key unknowns is the behavior of the sediments. The heat 

 emanating from a canister during its initial 500 years may cause part of the 

 sediments to rise and parts may harden into a brick-like substance. Experiments are 

 planned to test the response of clay sediments to implanted heat sources. 



Question 10. What do we know about the dose rate to deep sea organisms? 



Answer. We do not know very much about this problem. This is being addressed 

 in a number of ways, including studies in areas where low-level radioactive waste 

 have been deposited. 



