tion products may account for as much as 20-50% of the photon intensity during the first day post detonation, however, most Na-24 and Mn-56 activity remained close to the point of creation. Bikini Atoll. In the case of BRAVO this was near Namu Island, It is doubtful that Na-24 and Mn-56 contributed to exposure rate at Rongelap Island because they were created hundreds of kilometers away. An assessment of the exposure rate contribution from the accounted for nuclides at distances far from the detonation site was approximated based on studies of fallout composition at the Nevada Test Site (Hi81). An approximation of the exposure rate due to all unaccounted for nu- clides listed above would be less than 1% of the total exposure rate on day 0.5 post detonation. This may not be a fair comparative assessment since a device like BRAVO was not reported as being studied at the Nevada Test Site. e. Input Data to Kinetics Equations A check on the activity per unit fission data at any time was made. The theoretical activity of unfractionated iodine isotopes following 10,000 thermonuclear fissions of U-238 as given by Crocker (Cr65) were compared to the activity at any time following fission of U-238 with 14 MeV neutrons as calculated here. The comparison calculation was made using decay schemes from Table of the Isotopes (Le78), independent yield data for fission products from the National Nuclear Data Center (EN82) or from Crocker (Cr65) and Eq. 4. The Crocker yields were based on a slightly different neutron energy spectrum than that used inthe calculation made here. The kinetics equations, verified yield data and decay scheme approach resulted in remarkably similar results when compared to Crocker. The maximum difference, approximately 50% was for I-134 at two hours post detonation. All iodine isotope activities were within 20% of 20