Why consider subseabed disposal of high-level nuclear wastes

There exist large areas of the deep seabed that warrant assessment as potential disposal sites for high-level radioactive wastes because (1) they are far from seismically and tectonically active lithospheric plate boundaries; (2) they are far from active or young volcanoes; (3) they contain thick layers of very uniform fine-grained clays; (4) they are devoid of natural resources likely to be exploited in the foreseeable future; (5) the geologic and oceanographic processes governing the deposition of sediments in such areas are well understood, and have been remarkably insensitive to past oceanic and climatic changes; and (6) sedimentary records of tens of millions of years of slow, uninterrupted deposition of fine-grained clay support predictions of the future stability of such sites. Data accumulated to date on the permeability, ion-retardation properties, and mechanical strength of pelagic clayey sediments indicate that they can act as a primary barrier to the escape of buried radionuclides. Work in progress should determine within the current decade whether subseabed disposal is environmentally acceptable and technically feasible, as well as address the legal, political, and social issues raised by this new concept