the circulating winds. As a consequence, the up=-wind or cressewind distances become critical, the lateral spread of tho early fall-eut being such that relatively high radiation intensitics can oceur in these directions. For Operation CASTLE, it was assumed that the problems raised by this phencmens mad most likely cecur at HIXINI. This atoll, being relatively narrow along <l@ north-south axis, with ground zeros along the northern reef, and camp sites on the south (ENINMAN and ENYU), was assumed to be particularly suscep rible to the crossewind and up-wind fall-out. It was assumed that with detona- ‘sLens along the northern reef, with ylelds on the order of MIKE ant fired iwder the ground sere conditions of MIKE, fall-out on the ENINMAN camp ceuld 4e expected to reach a mocimm of 1.0 to 10.0 reentgens per hour within about 4s to three hours aftor H-hour, This could mean a delay of from one to. two weeks in putting the ENINMAN camp back into full time eperation. Condi- “ions on ENYU were assumed to be considerably better due to the greater distances from cero points and its relatively up=-wind pesitien. For the shots involved, the reef shot southwest of NAM) and the barge shots in the vicinity of YUROCHI, it was expected that the NAMJ siot should give thse mest trouble since its firing conditions would vary nearly approximate those of MIXES. Here the conditiens for heavy fall-out, namely the u-take of a large quantity of coral (to which the radioactive particles could cendense), would be such that the coral particle scavenging action should be as efficient as MIKE, resulting in considerable fall-out in the atoll area cross-wind and Up=cind, Since the barge shots were tobe fired in water of a depth approxi- mately that of the MIKE crater, it was expected that little coral cr bettom material would be taken up into the "hot" cloud, Consequently, the scaveng~ ing action in the atoll region was expected to be greatly lessened. [t snuid also be noted that the conditions for a highly radieactive base surge would