S| ~3 od} ; {SHATHOHYgag 3 From the data in table 1 (Appendix A) on Sr-90 production and an assumed average fission yield of Sr-90, it would also be possible to derive an approximate total fission yield figure for any of the listed operations, both in termf of weapons with total yields of less 1 megaton and those with total yields of over 1 megaton. It would thus be possible to derive a total fission yield for all U. S. operations through the Redwing Operation of approximately )6 megatons. This is more accurate than the 50 megaton figure given in the Joint Committee on Atomic Energy Hearings as the total fission yield of ali U. 5. weapons tested thru 1957. (See Appendix B). lh. Since the yields of only a few devices in PPG operations subsequent to Sandstone, have been published or may be declassified and yield information exchanged with the British has been carefully selected to avoid giving the total energy; yield in any given operation, it would not be possible to derive fission - fusion ratio information on the thermonuclear tests in these operations. Therefore, it is recommended that the data on Sr-90 production presented in Appendix A be declassified subject to the following provisions? 8 A ‘ (a) That release of additional yield information on tests in the Operations Ivy, Castel and Redwing (those involving thermonuclear devices) will be carefully reviewed prior to any exchange or declassification of such data (bo) Data on fissionable material used in individual devices after Crossroads operations is not to be released (c) Similar information on Sr~90 production for subsequent test Were? es! . yin Sayee (io eae 7p TeedLONE LNShereerae A ger ” wes