SUBJECT:
Radiological Survey of Downwind jitolls Contaminated by BRAVO
that ono survey metor could not be properly zoro adjusted.
Tho four remining
‘N/PDR-39, still oporated officicntly and socmed to bo in good working ordor,
@ne (1) cach Bockman MX-5, and one (1) cach AN/PDR-274 was
for any low intonsity chocks noccssary.
Two (2) cach calibrated AN
brought alor
T1B, we)
on hand to servo as spargs in tho ovont of operational failure with tho AN/PDR-
None of theso instrumants woro roquirod.
*
6. Tho avorago and‘ maximum gamma doso ratos measurod on tho various islar
of cach atoll aro plottod in Figures 1 through 5. All moasurements wero mde ai
waist hoight unless othorwisc indicatcd,
The mximum readings do not include
moasurements mado with tho instrument next to a contaminated surfaco.
Dotailed survoys woro mado of all tho inhabited localitios.
Typical
readings aro givon in Tablos 1 and 2 for tho nativo villago of Rongolap Island,
and the 1G 7.4 camp on Mniwctak Island.
In gencral, the villages and the camps
appeared to havo slightly lewcr averago doso ratos than the romaindcor of tho
island. This can porhaps be ascribed to difforent gcomotry of the contaminatia
and to slightly grcatcr penotration into the leoso gravol in the nativo village:
Tho doso ratcs inside the native huts appoared to bo almost tho samo as the doe
rato outside,
The doso rato in the middlo of tho military barracks, tents, and
shacks was 1/3 to 1/2 that outsido, This reduction is probably largely a Boome
cffoct. The dose rato foll off rapidly on tho beach below the high tide ork,
Thero was no ovidence of rain washing off the contaminatcd mtcrial., The foila,
on the windward sidos of tho islands appcarod to be slightly abovo avcrago con—
tamination.
,
TABLE 1
TYPICAL READINGS IN RONGELAP VILLAGE — 8 MARCH
Location
Dose Rato (ar/hr)
Rongolap Island (average)
375
Center of village
Noar central cistern
280
300
Near northern cistcrn
350
Near southern cistcrn
220
TABLE 2
TYPICAL READINGS IN CAMP ON ENIWET#K Is. - 10 MiRGH
Location
Outside Dose
Rato (or/hr)}
Inside Deseo Rate {or/nr)
Eniwotak Island (average)
280
--
“= 260
160
Mess hall
Tent, cdge of min camp
Latrinc
Slecping quarters
Dispensary
220
270
260
220
119
175
9%
ore anssscencacemaasanal