SURVEY INFORMATION
Tabulations for the islands cf 31ikini Atoi. on the following pages will
indicate:

].

the background gamma exposure rates as measured with a
Baird Atomic NE-1484 scintillator calibrated against !37¢c,

2,

a summary of the radiological waste removal and disposal,

3.

results of sample analyses and,

4.

when appropriate, projection of the background decay as a
function of time.

CONCENTRAT ION-EXPOSURE RATE RELATIONSHIP

In order to estimate the expected reduction in exposure rate for the
various iSlands as a function of time, it was necessary to develop
weighting factors for each of the gamma emitting radionuclides identified
In the analysis of soil samples.
For purposes of this report, it was assumed that the various radionuclides
were uniformly distributed by depth throughout the soil and that the only
change in relative concentrations is due to the differential decay rates.
This is obviously an oversimpiification but would tend to give conservative
results.

The data of Crocker, Connors, anc Wong’

(4)’

were used to indicate

the relative effect of each nuclide on the exposure rate.

Since 102Mpp

was not among the nuclides included in their tabulation, data from their
table were normalized by effective energy and number of photons per
disintegration and plotted.

The exposure rate factor for 1 O2MRb

effective energy 0.62 MeY was taken from this curve and corrected
for 2.96 gamma per disintegration.*

The final tabulation of the composite

exposure rate reduction was then calculated using the decay factor,
initial concentration and exposure rate weighting factor.

*Decay scheme taken from Table of the Isotopes - Ledever, Hollander, and
Pertman.

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