Monolithic cement-solidified products of simulated evaporator concentrates from LWR packaged in 200l drums have been subjected to leach tests of radionuclides. The leach tests were carried out under the condition which simulates hydrostatic pressure, temperature and flow velocity on the sea bed of 5, 000m depth. The principal results are obtained as follows:
(1) No radioactivity in the leachant could be detected during the test extended to 675hr on a cement-solidified product with asphalt capping. Water ingress through the asphalt capping layer was not perceived.
(2) Solidified packages with intentionally prepared bare surface were tested to find out leaching coefficients (apparent diffusion coefficients) F
l. Values of F
l were found to be 1.6×10
-4 for
137Cs and 1.2×10
-9cmcm
2/day for
60Co, in case of the blast furnace slag cement (C-class) solidified product of simulated waste from BWR. As to the Portland cement-solidified product of simulated PWR waste, F
l was 1.5×10
-3 cmcm
2/day for
137Cs.
(3) By using these leaching coefficients, a long-term estimation of the amounts leached out was attempted considering the decay of radionuclides.
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