A central radiec repair centerand a 1¢°7.3 radiec equipment .pool.were maintained on board the BAIROKO by two Slectronics Techni¢iens assigned from the Staff of CTC 7.3. This force was sufficient to celibrato all instruments of TG 7.3 brought to them for calibration, end to repair all rediac instroments which shipe' persermelwere “unable to repair. In rddition, these ITs instructed cll ships! personnel who required instruction in use and maintencnce of radiae equipment. Monitoring drills were onde rerlistic by the use of rediation sources. | On 1 March 195%, ct O645M, the first nuclear explosion (REAYO) of Operrtion CASTYE wes: detonated. Prior to the cotonation, shine of Task Group 7.3 hed been deployed at ‘see. generoily in the soutk- eest ounicant from ground zero. This disposition an¢. its location were brsad on four principal factors, (a) the latest OST¥ SEVEN redex, (db) the requirements of the Commander Scientific Task Group (C2G 7.1) that ESTES (aGC.12) end CUATISS (aV-4) be vositioned bout 12 miles from SNYU Islend for relicble CRF communicetions end Reydist purposes; (c}'the recuirement that shive de disposes at safe ¢istences (ft least 70 miles) fren ground zero to rroid hercful heet, and bleet effects, end (d) tho requirement of reasontble concensretion for communicrtions en¢ control pamposes. Prior to the dotonnation end beceuse lrter wind cate begrn to indicete an casterly component, some of the sneller and slower units were directed to move-to the south, but the lerge> stipe “wore rete!net in the localities indiceted in view of the fore Jzae-6