Chapter 5 SUMMARY, DISCUSSION AND CONCLUSIONS 5.1 SUMMARY In Chapters 3 and 4, independent sets of data relating to the radioactivity of sea water which had received fallout were presented. Computations were carried out so as to pro- vide isointensity contours for Shots 5 and 6 as though the fallout had been received by a fixed plane at mean sea level. Dose rates at H+ 1 hour or H+ 12 hours are calculated at 3 feet above the fixed plane. Dose rate contours for Shot 5 are based upon the direct measurement of gammaactivity in the sea water by towed radiation meters. A comparison of these results with those calculated from laboratory analysis of sea water samples taken at 23 locations is made in Table 5.1 and shows good agreement. Contours showing accumulated dosages at H + 50 hours were also plotted for Shot 5. One conclusion evident from these contoursis that total doses of 250 r or more could have been accumulated throughout an area of about 5,000 square miles. Contours for Shot 6 were calculated from water sample data; aerial survey traces were used to sketch in contours where water sampling was not done. Using these contoursfor Shots 5 and 6, the radioactivity appearing in the fallout area was summed in Chapter 4 to provide the fraction of the debris from the devices which appeared in fallout. Ten percent of the debris from Shot 5 and 8.5 percent of that from Shot 6 was accounted for within the fallout contours as drawn from radiation meter and water sample data. 5.2 DISCUSSION AND CONCLUSIONS The agreement between the two sets of results for Shot 5 is gratifyingly good; it is recognized that the several arbitrary assumptions and approximations madein this report may have introduced systematic absolute errors which are extremely difficult to evaluate at this time. Nevertheless, it is concluded that radiation instruments submerged in the ocean and water sampling at representative locations and depths each result in data from which the fallout pattern can be determined satisfactorily for certain types of det- onation. To accomplish this, supporting oceanographic and radiological data are needed. The principal deficiencies of the present work are believed to lie in the quality of the supporting data. It is evident that on future surveys better data are needed in the following areas: (1) rate and depth of mixing of fallout; (2) physical and radiochemical characteristics of fallout, especially particulate size and radioactive decay; (3) times of arrival of fallout over the fallout area; (4) details of the action of ocean currents in dispersing fallout; (5) spectral distribution of gamma radiation from fallout; (6) relationship between intensity of a gammaradiation field and radioactivity per unit area of the source which produces the field; (7) calibration of radiation measuring devices both for field measurements and laboratory measurements and throughoutthe full range of gamma energies; and (8) accurate geographical positioning of all ships, planes and stations conducting surveys or collecting samples. The two survey approaches described above give almost duplicate numerical results, but each hasits inherent advantages. The direct gammaradiation meter is well suited 77