(9) Source sise, IVY MIKE indicated that the arrent sethods
of predicting fall-out on the assumption of a point source (or at best, 5
very small source) were not acceptable for high ylelds. Consequently, CASTLE
forecasting was originally made on the sasumption.cf 9 circular source
approximately 1§ miles in radius (i.e. the approximate radius of fall-cut
crosavwind and updnd from MIKE).
BRAVO results indicated thie to be somewad
small, and probably more like an eilipee with a semi-eminor axis of about
25 miles.
For the barge shots, the L5-aile eireular radius (actually nore
elliptieal than circular) appeared to be adequate.
Tienet effeet of the
above was to consider the surface RiDEX constructed om a point source type
analysis as a generating elawnt.
Shifting the point sarce RADEX arcund
a source area selected in accordance vith yield end type of burst generated
the complete area which shouldbe considered in the surface RiIDEX.
4
similar adjustment wes made to the Air RADEX forecaste with excellent
results in defining the areas of contamination waich resulted.
f. Construction of RADEXES and Fall-cut Plots, Generally
speaking, the RADEX ares (RiMiclogical BXelusion ares) ws considered to be
&@ limited fall-out area for the first six hours post-shet in the vicinity
of the teat aite amt for the primary use of test personnel and equipment.
Area fall-cut plots were conaideryd ta be the entire area of significant
fall-out, to’ inelude infinity isodcee lines of at least 50 roentgens, and
in seme cases dow to 10. rcentgens.
The RADEX was used es a operational
devies to define dangercus areas and to deny entry of task force units into
Certain areas exsept under spesifie suthorisation, 2 a consequence, it
owe
way given wide dissemination throughout the task forces for the information