Taoie |.

Comparison of gross
fission procuct
total external. doses
for
.
.
Ps

computer
Strauss?

calculations

(hours)

Rongeiap

(northern oart)

(racs)

51

nongelao

(southeastern part)

Rongerik

(southeastern part)

Ctirik

by

Previous
Estimates

Dunning!

(roentgens)

2000

(6]

110

173

[5]

58

24

<100

{5}

30

340

78

.(5]

vV10

{5]

=

78

0.33

and

Ref.

1300

51

Ailinginae
(Sifo Island)

estimates

Present
Caleulations

Evacuation Time

Atoll

vs.

With the modified MATHEW-ADPIC code suite, it is possible to calculate the

instantaneous immersion dose rate from gross fission products as.a function of
time.

This ean be done for any time inteval.

Figures 2a to 2f show surface

immersion dose rate contours for every three hours from one hour after Bravo cloud
stabilization time to H+16 hours.

Note that after an easterly traverse, most of the

cebris reaches the trade wind level; the contour pattern moves south and finally

toward the southwest.
Individual Nuclides

Calculations were made of instantaneous and time-integrated concentrations
at 2 m g50ve the surface for the several atolls affected by Castle-Bravo.
nuclides

considered

were

Te-129,

I[-131,

I-138,

(Cs-137,

and

Eu-155.

The
These

calculations agree well with observations at Rongelap and Ailinginae atolls, but are
too high at Rongerik and too low at Utirik atoll. The surface concentrations for
mangalac. Doth the northern and southeastern darts of the atoll, and for Ailiginue
Atoll are presented in Figures 3a to Se. The time of arrival of the first Bravo debris
is in agreement with reports made by the inhabitants.

Select target paragraph3