W. R. Kennedy, 8-6
122518
"CLOSE IN FALLOUT" FROM CASTLE BRAYO
K-6
Tre folloving measurements were made at various tims at the places indicated
following the March 1, 1954 detonation at Bikini Atcll. Gpeed of movement to
all points is based on a measurement by a recording gamm meter located on
Eniwetqx Island, Rongerik Atcll.
~
The meter indicated start of arrival at
H + 7-3/4 hours, with an estimted peak reading at H + 6-3/5 hours.
distance is 135 nautical mileg, so a mean speec of 17 knots
the calculations. Extrapolated decay has been based on the
‘the
been used in
T°? rate. Ho
gllovance bas been mide for weathering prior to measurement, so the valucs
are probably Low.
The boxb was a surface burst of 15 Megatons, 50% fission. The “hot line” of
the fallout pattern was aomvhat to the north of all the locations listed
below.
Kabelle Island, Roagelap Atoll, is the closest to the “hot line”,
but still probably somo distance from it.
island
Dste-
Reading
Raigelap
D+ 7
375
103
H¢6
Location
time
me/hr
Distance
Estimted
sea miles
Estimated
Arrival time
Xabelle
D+25
1000
108
Enivetgk
D+ 7
280
135
H+8
Utirik
D+3
170
276
H+16.2
Peak reading
© R/hr
B+ 6.35
Estimted
DP c-
600 R
235 R/hr
7500 B
ll B/nr
LhO R
1 B/hr
&1 R
Ava Sigua Tay
VALLIAN Ro K¥eusstier
Wu.
R.
Kennedy
WRKi be
ec: 0.W. Stopinskt
ER. Benis
File
RG
326 US ATOMIC ENERGY
COMMISSION
Location
Set|
F-23
B-17>
CollectionLec a atc Cedber
Folder BRAVO
POPIED/DOE
RANL RO
wnertint
Oetober 20, 1961
Carl Buckland, H-1