Page:Operation Crossroads 1946.pdf/57

 EXCLUSION AREAS AND OPERATION LIMITS

Surface Operations

To reduce the chance of exposing task force personnel to radiation, several surface areas were defined by the Operation Plan to which access was forbidden or restricted (Reference C.9.206, p. VII-(C)-9):


 * 1. Surface Survey Sector. This was a forbidden surface area outside the lagoon. It was bounded by two bearings drawn from the detonation point and by a radius that increased with time after the detonation


 * 2. Red Line. This line surrounded the lagoon area within which the radiation level was 1 R/24 hours or higher. This boundary was separate from the Red Arc that defined airspace limits.


 * 3. Blue Line. This line marked the boundary between the lagoon area with a radiation level more than 0.1 R/24 hours and the area with a lower level. Vessels could operate in the lagoon area between the Blue and Red Lines only for specified periods of time with permission from the Radiological Safety Control Unit. Vessel movement outside of the Blue Line was governed only by regular Navy rules.


 * 4. Anchorage Area Able. Ships could anchor in this area, provided they were ready to get underway on 1 hour notice.


 * 5. Anchorage Area Baker. An unrestricted anchorage area.

In addition, certain operational limits were specified. No manned ships were to be closer than 10 nmi (18.5 km) from the ABLE detonation, and most were to be 20 nmi (37 km) away (Reference B.0.1, p. E-IV-1). In case of fallout on the ships, nonessential personnel were to be sent below decks, the ship closed up, and exposed personnel were to strip off their outer clothing before taking cover. If necessary, men in coveralls and gas masks were to decontaminate contaminated areas of the ship after fallout ended (Reference B.0.1, p. E-IV-7).

Before each test all ships were to have full freshwater tanks. Distilling plants and heat exchangers were not to be operated until the Radiological Safety Section had declared the saltwater to be used was radiologically safe. If the equipment had to be operated before radiological clearance had been given, special monitoring attention was required (Reference B.0.1, p. E-IV-10).

In order to gain access to classified or radioactive areas, the leader of a work party was required to present an identification card and a letter of authority. There were letters for damage control, instrumentation, observer, press, and radsafe parties, among others (Reference B.0.3).

Aerial Operations

Initially Joint Task Force One Operation Plan 1-46 (OpPlan 1-46) prescribed certain general safety precautions for air operations. It specified that all aircraft aloft from H-2 hours to H+30 minutes carry a radiation monitor with monitoring equipment. Exceptions were the bomb-drop and pressure-gauge-drop

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