developed from Figure 10 for six different yield weapons and for two
different burst heights above the ground and indicates the percentage
of fall-out to be expected in these cases.
TABLE 2
Ht.of Burst
Yield
(feet )
1k?
50
1K
5 KT
5 kt
10 KT
180
Radius of Fireball]
28
% Fell-out
Relative to
That From a
Surface Burst
50
180
-56
25
50
340
015
67
50
460
460
222
ell
75
100
50 kT
Fireball (ft)
Height of Burst
100
100
10 kt
Radius of
340
30
48
57
50 kT
100
50
870
-06
86
500 xT
500 KT
50
100
2200
2200
02
205
95
89
50
2900
-02
° 95
1000 KT
1000 KT
100
870:
12
2900
203
73
95
An uncertainty of great potential importance exists in the current
state of knowledge regarding the maximum dose rate intensities that are
likely to be encountered on the ground following a true land surface
burst.
This uncertainty exists because only one nuclear detonation has
occurred thus far on a true land surface, and this one experience was
for the relatively low yield of 1.2 kilotons at Operation JANGIE.
A
crater and lip dose rate of 7500 r/hr at H+l hour was recorded after
this shot.
Although scaling laws would predict an increase in crater
and lip dose rates with increase in yield, such higher dose rates have
not been observed following the large yield surface detonations at IVY
and at CASTLE; instead, the highest well substantiated dose rate readings at 1 hour after burst for any of these shots appear to lie in the
range of 5,000 to 10,000 r/hr.
Some have theorized that this is due to
' the fact that the crater lips have been washed by waves and that the
48