4. PLANNING AND CONDUCTING NEVADA TESTS Origin of a Series _ As weapons developmental work progresses,‘ new ideas origi- nate in the weapons laboratories, new requirements for weapons are posed by the military, or important new questions are asked as to design, efficiency or effects. .As the various test projects accumulate, a series is scheduled tentatively for some ' future period, generally about two years away. The winnowing out of test proposals for a specific series may begin a year in advance. Usually at about eight months in advance, plans are sufficiently firm to begin the procedures es- sential to starting construction and organization. At about five months, programming has progressed to the selection of an operating period and determination of total number of shots. Each Shot Justified for Technical Necessity Each Nevada. shot must be justified as to its safety, but before then it must have been justified as to its importance to the nation. Only tests which are vital to national atomic pro- grams, only those which contribute directly to the defense of this Nation and of the free world, are admissible. The Nevada Test Site Planning Board examines each proposed nuclear test to determine whether it is technically necessary, whether it can be fired safely in Nevada or must be transferred to the Pacific, and whether the device and its associated experiments can be ready at the time required. If the test meets all the criteria it is incorporated into the schedule for a Nevada series. Operating Considerations Requirement for Technical Success. Each experimental device fired must be designed so the required diagnostic and effects information sought can be obtained with the minimum expenditure of fissionable materials. Requirements may include a new type of instrumentation to obtain diagnostic or effects data, and if so there must be assurance the data sought will be obtained. Public Safety Requirement. No shot is scheduled in Nevada until a determination has been made that its firing will be ac- ceptable under established criteria for offsite radicactive fall- out. Because height of the detonation above ground level is a determining factor in nearby off-site fallout, a device that ‘ Llhy, “<p %, -13- I ‘