-5The Committee recommends that the surface shot be carried out first followed by the scaled underground shot on schedule, unless some adverse occurrence becomes evident, in which case the Committee would review the evidence for further discussion. These changes in criteria and recommendations are based largely on the consideration of the study and oral presentation of Felt. Dr. Gaelan A copy of the written study is attached as Appendix I. Dr. Felt pointed out that itwas the feeling of the Los Alamos Laboratory Test Group that the deep underground test was unnecessary from a radiologic:l safety point of view. This opinion was based on their consideration of the Trinity data which most nearly approximatethe surface burst. He has constructed a theoretical model, scaled to fit the Trinity data amd the conclusions of this work indicate that the surface burst would probably be the safer, with the scaled underground being the second choice, and the deep underground the third. It was the feeling of the Committec thet the selection in order of bursts should be made on the basis of considering the shot one Imows most about; thus, the surface shot which most closely repeats Trinity should come first. It was pointed out thet the height of the cloud is one of the important factors to consider from the radiological safety point of view. The higher the cloud the better the chances are for dilution, dispersion of the radioactivity, and minimal concentration of radio- activity on the ground due to fall-out. There is evidence that the radioactivity is concentrated at the top of the cloud. The Ranger shots showed that the path of the low clouds will be greatly dependent on the terrain, The fall-out from the lower portion of the cloud will be more dependent on turbulence factors, The higher clouds are sheared and the radioactivity dispersed more quickly due to the higher wind velocities, with grsater chance of predicting the stability of the higher winds. There was considerable discussion regarding the level of radio- activity that outside populations should be allowed to take ~ a memo by Dr. Shipman, Appendix II, was read by Dr. Warren. Dr. Shipman points out that an exposure of 5 to lOr is not likely to harm anyone, and that this would be in line with the AEC emergency dose of lOr,