ABSTRACT
This report contains a description of the mission, responsibilities, organization, and
activities of Tast Unit 7, the Radiological Safety Unit of Task Group 7.1 during Operation
Castle. The chapters are devoted to a general discussion of the organization, activities, and
recommendations of the scientific sections necessary to implement a thermonuclear test
radiological-safety unit.
Appendixes and illustrations contain specific details of certain operational procedures,
radiological situation data, and fall-out decay curves.
As a result of Rad-Safe operations during Castle, it was determined that contamination
resulting from high-yield surface bursts creates radioactive hazards over such large areas
that land-based operations at the Pacific Proving Grounds are in constant jeopardy. Watersurface detonations of thermonuclear devices created less of a radiological problem than
ground-surface d-_tonations; however, the most important factor in the over-all radiological
Situation was the disposition of the winds between 10,000 and 60,000 ft at the time of detonation.