CHAPTER 17 The final report, "Mechanism and Extent of the Early Dispersion of Radioactive Products in the Water,"® which was not issued until March 1962, states that it "ie the result of painstaking analysis of measuremente obtained,” but "for a mumber of reasons the measurements left something to be desired." According to this analysis, 32% of the total activity in the water was found in the thermocline (at 110 meters) and above, and 68% at depths of 200 to 300 meters. The deep activity was found to be complexly distributed in laminae that moved more or less independently of the surface and other waters. It was concluded that the mechanism that gave rise to this distribution was an emergence of a deep colum of water at early times following the detonation and a subsequent mixing of these deeper waters with the surface layers and their sinking to an intermediate depth as a result of instability. It is postulated that the emergence of the colum gave rise to a mass of water moving from east to west on the surface, perhaps due to the earth's rotation. Values given in Ref. 8 of early-time maximum radioactivity at the water surface, as determined by survey aircraft, are higher by factors of 3 to 7 than those given in Ref. 31. According to Ref. &, the 27 min, 33 min, and 130 min maximm surface dose rates over the radioactive c™ pool of 550 r/hr, 230 r/hr, and & r/hr, respectively, were derived by arbitrarily doubling aircraft results thet had been corrected to 3 ft above water. This doubling was done to roughly reduce these measure- ments to in-situ measurements made by the probe. The area of surface activity at H + 30 min is tabulated as 5.5 sq. mi. According to Ref. 31, the earliest aerial survey at H + 19 min established that the principal contaminated zone of water was about 2.5 miles in diameter, with an area of about 5.3 square miles, and at that time dose rates varied between 32 and 70 r/hr at 3 ft above the water. Several sets of radiac data-telemetering transmitters were dropped into the water by eircraft at various times from H + 2 min to D +1 day. It was planned for these instruments to measure the dose rates in about the top 6 inches of water and transmit the information to the primary radar room aboard the CVL-49. Of the original 5 sets dropped, telemetering pulses were received from only four. Of these, two units were of too high a range to produce data, and one unit transmitted intermittently. One unit produced consistent and apparently reliable data (although no range and bearing information was obtainable) that compared satisfactorily with information obtained from another unit dropped at D+ 5.3 hrs. Available telemetered data indicate that dose rates in the top few inches of water somewhere in the area of the original circular upwelling were about 40 r/hr at about 1 hr after burst, and decreased to about 1.5 r/hr at 6.67 hr (400 min). ABLE BEST AVAIL coPY. 17-97 Se ee ee rte eee nenaen Se ee