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2/24/67
PLAN FOR MEASUREMENT OF EXTERNAL NUCLEAR RADIATION
LEVELS AT BIKINI ATOLL, MARCH 1967
Purpose.
The purpose of this plan is to describe procedures to be
used (te-obtaining-date-thet-wittprovide-e-besta] for determining external
radiation levels that exist on various islands of Bikini Atoll.
Discussion.
.
In order to establish the levels of radiation that may
be found at Bikini Atoll, it may be worthwhile to review briefly the data
collected during the most recent sampling mission conducted in 1964 by the
University of Washington, under contract with the Division of Biology and
Medicine, and to present for comparison the reported levels for Rongelap
Atoll at the time of repatriation.
The attached Table presents these data.
The average level of external radiation on Rongelap Island (0.03 mr/hr)
at the time the inhabitants were returned was only slightly higher than
the average value used for natural background radiation for the U. S. population of about 100 to 200 mr/yr. or about 0.02 mr/hr.
The average level
on Bikini Island in 1964 was about 0.04 mr/hr with Enyu Island at a somewhat
lower level of 0.01 mr/hr.
These two islands contain the major land masses
within the atoll and as such represent the most likely areas of habitation.
Though these values are low, it is important to determine with confidence
the range of external radiation levels that exist on Bikini Atoll.
Such
external radiation exposures, above background, must be added to that from
internal emitters in order to arrive.at the total dose any permanent resi-
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- dent may receive from past tests.
Considering the uncertainties inherent
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