Management of Commercially Generated Radioactive Waste - U.S. ...

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food chains and ultimate consumption of seafood and radiation exposures to man. Although
there is some question as to the applicability of these models to the subseabed disposal
option, the following summary of results using these models is presented until such time as
better estimates of radiation exposures to man from subseabed disposal are available.
The individual doses resulting from the consumption of surface fish, deep-ocean fish,
or plankton are expected to be well below the maximum permissible levels. External indi-
vidual doses(a) from contamination of coastal sediments are expected to be fractions of
the ICRP dose limit for both skin and whole body irradiation. The largest annual internal
population doses to the whole body and bone due to the consumption of surface fish would be
about 4 x 104 and 105 man-rems, respectively. The largest annual external population
doses from contaminated sediments would be about 103 to 10 man-rems for both skin and
whole body. These large population doses would occur during the early stages of
postemplacement and would decrease during the later stages.
As an attempt to provide a further yardstick against which to compare the results of
the calculations, Table 6.1.15 gives the concentrations of nuclides predicted by the
modeling, as well as the natural activity in seawater.
6.1.4.6 Cost Analysis
An estimate of capital, operating, and decommissiong costs for subseabed disposal has
been made for both spent fuel disposal and HLW disposal (Bechtel 1979a). Both are based on
penetrometer emplacement. All estimated costs are in January 1978 dollars.
TABLE 6.1.15. Levels Of Natural And Wastes Radionuclides In Seawater
Max Widespread Surface Water
Conc. Predicted From Postulated
Natural Activity In Waste Disposal Operation,
Nuclide Seawater, Ci/cm 3 Ci/cm 3 (No Containment)
Actinides
Pb-210 (1 - 9) x 10-11 2 x 10-15
Pb-210 1 x 10-10 2 x 10-15
Ra-226 1 x 10-10 2 x 10-15
Th-230 (0.6 - 14) x 10-13 2 x 10-1 7
Th-234 1 x 10-9 1 x 10-15
U-234 1 x 10-9 1 x 10-15
U-238 1 x 10-9 4 x 10-15
Pu-239
1 x 10-12
Fission Products
H-3 2 x 10-10 1 x 10-12
Sr-90
4 x 10-10
1-129 3 x 10-11 3 x 10-1 4
Cs-137
6 x 10-10
(a) Based on world population