Evaluation on the disposal of radioactive wastes into the North Pacific

Evaluation on deep sea disposal of radioactive waste into the North Pacific on the basis of diffusion process is done using a simplified model. The results of calculation by employing different sets of diffusion coefficients on the horizontal and vertical directions show that for the smaller diffusion coefficients discrepancies between relative concentration of nuclides and the law of radioactive disintegration are greater. For larger coefficients, concentration above the site of release approaches mean, homogeneous concentration which satisfies the rule of radioactivity. From oceanographic and radiological view points, it is concluded that 102 cm2/s and 108 cm2/s respectively of diffusion coefficient of the vertical and horizontal directions are appropriate and reasonable in the North Pacific for the purpose of dose evaluation. A New definition of the high-level radioactive waste and other matter is given as follows: (a) 10 Ci/t for β/γ emitter (except tritium), 1 Ci/t for 90Sr plus 137Cs, (b) 104 Ci/t for tritium, (c) No long-lived α emitter may be dumped. (auth.)