DNA 1240H=2 It 48 difficult to obtain a coherent picture of the distribution of activity below the water surface, since available records do not agree well on this subject. According to Ref. 82, the maximdose rate encountered by the depth probe on the first day was 27 mr/hr at 1.5 hr after burst, at a mean lamina depth of 60 meters. At D+ 12.5 hr, about 21.5 mr/hr was recorded at a mean lamina depth of 122 meters, and at D+ 70.2 hr, a level of 23.6 m/hr was recorded at a mean lamina depth of 265 meters. According to Ref. 31, the GITR located at station 2 on the YAG-4O (about 30 ft below the water surface) provided another source of early in-situ dose-rate information from Shot Wigwam. The first pass through the contaminated area by the YAG-40 at 51 min after detonation took 25 min, and the unshielded keel station (station 2) accumlated a 3-r dose in that time and registered dose rates that peaked at more than 10 r/fnr. The water-sampling and analysis portion of Project 2.4 obtained samples of contaminated water from beneath the keel of the YAG-40 at a depth of about 30 f* and from 18 inches below the water surface. Early radiochemical analyses of a number of samples were made, and results are presented in units of counts/sec vs time after burst, and in mc/ml vs time after burst. It was concluded that the specific activity of the contaminated sres varied considerably from location to location, and the limited mumber of samples precluded any generalization regarding the total contaminated volume of water. Late-time water analyses and depth probes of the area, described in Ref. &, indicate that activity in the water was detectable ea late as 3 weeks after the shot. The results of this late survey were meager because the radioactive water did not move in the predicted fashion, and was not located until late in the period allotted for the operation. In May 1962, a nuclear devi cA2: detonated at about 670 ft in very deep water. Reduction of the data from Operation Sword- fish has not been completed, but aerial surveys were able to easily track the contaminated patch for 6 daye after detonation, and the surface ship was tracking the patch et least through D + le days. 3. Summary Water-contamination data from muclear water-surface and underwater bursts are limited, as the preceding paragraphs illustrate. Observations of the penetration of activity from water-surface bursts at Operations Castle and Redwing indicate that most of the water-borne activity became well mixed and remained above the thermocline for periods of many days. It was aleo observed that radiation levels in the water were low, not in excess of 1 r/fhr in situ. However, since few measurements were obtained earlier thnn H + 7 hr on any shot, mixing and decay probably ASL® BEST AVAIL copy 17-98 oe aN ge ne ee ne ren ce ee