Role of canister integrity on ocean bed disposal of solid radioactive wastes: Part I - Parent radionuclides

Uni dimensional model has been developed to compute spatial and temporal distribution of radionuclide concentration in seawater from sea bed disposal of solid radioactive wastes for 1000 y, contained in canisters of different integrity. The model is also extended to evaluate the concentration in seawater for times beyond the dumping period. The model takes into account oceanic diffusion, leaching from canisters, physical decay, geochemical elimination and reflection at boundaries. In addition, a radiological model comprising various exposure pathways to man, from ocean routes is used to evaluate the effective dose equivalent (EDE) to man. The results broadly indicate that the radionuclides studied can be classified into 2 categories based on EDE computed for canisters of different integrity. The first category consists of α emitting and some long-lived radionuclide s, for which the EDE to man is not significantly reduced by increasing the canister integrity except that the maximum exposure is shifted to future generations. The second category includes fission and activation radionuclides and the EDE from these nuclides can be reduced drastically by increasing the canister integrity. (author). 24 refs., 5 tabs