design principfes of nuclear explosives. fhe evolution of atelivery systens seetrslike1y to carry nore practical import ance in the future, as it has alreadlr done fnz cnna rroavcA/35/392 English Annex Page 38 C, Nuclear testing Bf. A most crueial question is vhat influence nuclear-weapon tests nay have onthe fut're developnent of varheads, as the s.nsver is of central inportlnce to theefforts to achieve a comprehensive test ban. The nuc]ear test activity is stilr_considerable. Since the first nucl_ear explosion in l9)+5 the nuclear plwers haveperforraed more than 1,200 nuclear tests. The exact nrimber is not officiallyknovn, but some more detailed figures are given in chapter fV. 87- According to Anerican sources, 11/ united states tests during the late fg70swere conducted for the fol_l,owing naii--purposes: (a) Tmprovement of yield-to-weight ratiosr (b) Reduction of varhead cost anal special nuclear naterial and consumption: (c) Enhancement of warhead safetyi (d) fncrease of veaI)on controL to prevent unauthorized use; (") Tailoxing of weapons effects to specific nilitary needs: (f) Understanding of long-tern cb.emical and structu"al stability. This reflects the technofogicar trends d.escribed. above. The list contains thep'rloses fox advanced crevel-op'ent and testing stated to be important iu view ofthe possibility of a comprehensive test ban. A naJor purpose for testing isnormarly the requirenxents caused. by adaptation of l./arhead.s to nel, or nodif.iedlrcapon systenrs or vehicles. BB: The distribution, by percentage, of tests made in the United States from theend of 1963 to 19?1 ( exctuding 21 "pr.ovshare " tests for civir obJectives) h.; ;;;"presented 12/ as foltovs. 1]/ Effgcts of a gonprehensirre test ban treaty on united states nationslthe Strategic Arms LinitationTalks and the comprehensive ?est Ban treaty of the rntelligence and Mir-itaryApplication of Nucrear Energy subcomnittee of the conmittee on Arms services,House of Rep"esent at ives , 95th Congress, Second Session, August 19T8.