in this report will be directed to environment levels on Bikini and
Eneu, the islands being rehabilitated by DOI.
‘
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Comparison of External Radietion Survey Results
Table I of this report is & summary of external radiation levels
for Bikini and Fneu.
These data indicate that the 1967 values for
Bikini and Eneu were essentially correct.
It is suggested that the
values for 1969 are not different enough to warrant recalculating external
exposures and that Dr. Gustafson's values in Table III ofAttachment 1
and Table VIII of Attachment 2 still apply.
The estimates in the column labeled "Modified" in Table IIi of
to
Attachment 1 are obtained by assuming that the village area or areas
around homes are covered with a Layer of clean coral gravel 1 to 2
inches in depth.
A further reduction in.external dose may be expected
by a factor of two to ten for that exposure received during time spent
Sndoor's since homes are to be constructed from concrete blocks made
from local materials.
This reduction may be optimized by selecting
sand and aggregate for meking concrete from locations in the Atoll
having the lowest levels of radioactivity.
The external exposure estimates in Table VIII of Attachment 2 are
based on the assumpticn that 2 inches of clean coral gravel ‘coverthe
ground around housing.
However, a shielding factor for concrete block
psseohtodlf 0
77 — 33%