Chapter 5 CONCLUSIONS and RECOMMENDATIONS 5-1 CONCLUSIONS The most striking difference between the fission~product| obtained for the Castle tests occurs in the regionof the trough of the fission yield curve; ! mn ~s 4 OA — | ee With the exception of Shot 3,4. — 4 a ' ‘}itcan be shown from the heavy-element data that pluto- nium fissions were a negligible fraction of the total fissions in the Castle detonations. The U25"/f ratios for the series clearly indicate that the events were of a thermonuclear nature. | The presence Of measurable amounts of the heavier plutonium isotopes such as Pu2® in the debris is evidence of the thermonuclear nature of the Castle events. —, The isotope Pb°?wasreported for Shots 3. 4, and 5, ee ——~" Only rough estimates could be made of the modal specific beta activity values, since the observed frequency distributions covered a broad spectrum of specific activities with no pronounced peaks. Modal values for the barge shots were much greater than those from island shots. The! gas sampling system proved to be a satisfactory collection system, provided certain operational and maintenance techniques were employed in its use. Radioactive gases of interest resulting from the explosions were detected close- in to the si site of detonation. i . a ——ne-Sorre lations could be made between radioactive gas concentrations and the characteristics of the particular device under test due to the extreme variations of these quantities. The causes of these variations are not readily apparent, but may be due to non-representativeness of samples, fractionation of gaseous debris, cross-contamination of an in- advertent nature in the sampling equipment or in laboratory analysis. 5-2 RECOMMENDATIONS All future U. S. nuclear tests should be monitored employing present 43