efforts on 3-4 March were directed at cleaning up "hot spots"; hence, the decreaseir
average topside intensities is due mainly to natural radioactive decay.
At the time of Shot ROMEO on 27 March, the BAIROKO was steaming in
company with the EPPERSON southeast of Bikini Atoll.
At approximately 1400 hours,
it returned to Bikini and anchored in the lagoon where it remained until 5 April. At
2000 hours on 28 March, the BAIROKO began receiving secondary fallout from the
ROMEOcloud (Reference !0).
Average intensities on the flight deck peaked at 25
mR/hr during the early morning hours of 29 March, and the ship's washdown system
was turned on intermittently between 0130 and 0400 hours. There is no mention in the
BAIROKO's deck log that further efforts were made to decontaminate the ship on 29
March.
On 30 March, intensities were down to approximately 10 mR/hour.
Figure 2-
{2 shows the buildup and decay of the Shot ROMEOfallout on the flight deck of the
BAIROKO.
Also shown is the Shot BRAVO background radiation on the ship and its
contribution ta the total recorded intensity.
The BAIROKO did not receive any more
fallout following the four remaining shots in the test series.
In addition to exposure from fallout, the BAIROKO's saltwater piping system
became contaminated while at anchor in Bikini Lagoon.
By 4 March, "the average
intensity in berthing spaces below the hanger deck was less than 2 milliroentgens per
hour (gamma only)" and on 8 March, "the saltwater piping systems did not exceed 2
milliroentgens per hour (gamma only)" (Reference 17). This reference also states that
"all fresh water samples from the evaporators tested by Task Group 7.1 have shown
1/5000 micro curies per milliliter or less." The ship contamination model developed in
Section 2 is used to determine the crew's exposure due to ship contamination. Specific
dates and times in and- out of the lagoon, along with corresponding integrated
inténsities, are detailed below.
Time at Bikini Lagoon
Month
March
In
03/0834-12/1720
13/0720-26/2034
April
27/1400-05/1226
Integrated Intensity (mR)
Out
In
12/1720-13/0720
26/2034~-27/1400
53
108.3
49.7
16.2
Out
1.9
0.8