x . ) i —_— — ) . FALL OUT (Authority: Commander Russel Maynard, Headquarters, JIF 132) Maximum expected on Eniwetok and Parry with worst probably wind condition is delayed airborne contamination that could raise the level of the island to hr/nr after 10 hours or same level out at distance of 180 miles, Red-safety limits of exposure are: .3r/week on life time basis. Total allowable ons time dosage for IVY is 3r measured gamma only with special provision for pilots of sampling aircraft of 20r measured gemma only. A one time dosage of 25r is currently used in civil defense con= cepts of operations but is not applicable as a general guide in IVY -/*/™ 4 t- unlese as an accident. are Vv However, no one is expected to be exposed to radiation rates approaching hrfhour, If such levels as these should be experienced on the islends of Eniwetok and Parry, a level of hr/hour after 10 hours does not actually decay very rapidly according to cal@< culations for such delayed fall out. However, from actual field exper- ienee, it has been found that weathering (i.e., wind, rain showers, etc.) ef such fall ont on the grourmi reduces the levels by more than 50% in one dey or according to tables: 10 hours = 4 r 20 hours - 2 r LO hours - lr 60 hours = 5 F Little is to be gained by covering large regular objects since when the reentry can be attempted for persons, levels of radiation on the equip= ment will in general be low. However, where equipment open te airborne contamination is complex, such as radio consoles or power control benks or motor generators, fail out contamination can be materially reduced fram collecting in such inaccessible spots by some covering, Hoods, when closed, on vehi¢le angines should suffice te reduce oily, greasy surfaces me pe 8 .