Operation Sandstone - Nuclear Explosions - 1948

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Monitors are assigned to survey work as follows: 2 Ioiiitors Enlwetok Island (See para. III B 6). 12 ” To Survey Zero Island 4 ” To Survey Islands adjacent to Two groups of two Monitors each will Monitor Wlri, Rojoa and Runit Islands and other islands adjacent to Zero Island. %ch group will carry radio equipFour Groups of those monitors each will monitor Zero Ali buildings and other construction on the island, including special AEC construction, will be marked to assist In orientations and preparations of radii mossagos to Radops. Vhcre construction and other terrain features do not perr?it adequate orientations a system of marked stakes will be installed. All monltoring.groups will be issued appropriate maps for the accomplishment of their mission and will have adequate facilities for radio communlcatlon. A. Monitor requirements for service tests not under 1. Bu Y and D to expose structions and instruments, taking photographs of structures both before and after explosion. “After” photographs to be taken from xray plus 2 to xray plus TO. One monitor per day. B. Monitor Rehuiremcnts for Service Tests underJTG-7.6. 1. JTG-7.6 to collect film badges, neutron detectors, etc., from xray plus 2 to xray plus 8,. Three monitors per day. 2. JTG-7.6 to collect cascade lmpactors and collective protectors on xray plus 2 xray plus 3, and xray plus 13. One monitor per day. ; fret? xray plus 2 to xray plus 13. One monitor per day.

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Notes on Operations The C-47 with monitortook off from Eniwetok30 minutes following the test, Northeastof the zero islandand upwind, it encountereda small amount of falloutalmost at once,but proceededon its mission at 5#00 ft, with a backgroundof 4 mr/hr. Phase one consisted of flightsover the craterat variousaltitudesin order to determinethe radiationintensityabove the-crater, It was flown at heightsup to 5sOQOf'to During this survey,readingswere radioedin code to the USS MT MCKINIJEwheneverthe plane crossedan active area, Phase III includeda check of the islandsto the west of the test island at an altitudeof 200 feet, Readingsof 500 mr/hr were obtainedover the on these islands, Phase II, a check of the air over the craterat 5,000 to 1L),OOOfeet elevation,was then begun but the intensityat .A furthersurveywas made on X-RAY-plus1, followedby a recheck on &RAY-plus 6, at which time the groundmonitorswere also surveying the crater, Final analysis of these data is awaitingstudy of the decay curves,but it appearsthat excellentresultswere obtained, Evidenceof fall-outan the islandsadjacentto the test island was later confirmedby the ground survey., and two assistants, The first members of this party arrivedon Eniwetok Island,30 March, A radiologicalsafetycenterwas establishedin the radiochemistrylaboratory,,This locationwas in close proximityto the drone par- area and Frovedto be ideal for the missionat hand, P and continual watch was kept on this curcuitwith the RadSafeCenter on the MT MCKINLEYand Radops on the BAIROKO, Canpleterehearsalswere held on PRTER X-RAY Day with the drone landingsand it was estimated that two monitorscould handle the filter removaloperation,, At 0725 followingthe shot the first drone plane landed, The drone planeswere not parked together, This causedsome confusionand it was very di?Yicultfor the monitorsto keep in contactwith all the on their way to the states, None of the personnelinvolvedreceived the tolerancelimit of 3 r on this mission, After all of the filters were removed it WLLSapparentthat thc;airpersonnelcould remove their data fram the drones,as well as the film badgeswithout exceediq the

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Washing down and deco+amination of the droneswas accomplished by the air monitors. The ?,ashing was completedby the morning of activitywas observedin any of the salt or well water intakes. By &BAY-plus 3 the island and swimmingbeacheswere clearedand by X-RAY-plus5 the &ones were clearedfor flightto Kwajalein, The purpose of the Ta&-u;M operationwas to procurea soil sample from the craterat the point of detonationof the atomicweapon, A tank revetmentwas built on each of the test islandslocatedas far as possiblefram the zero point, In this revetmentthe chassisof a light tank, brilliantlypaintedfor easy visibility,was concealedat the time of the test, It was equippedwith remote contMs,which permittedthe vehicleto move eitherright, left, or forward, It was also fittedwith a scoop in front for the purpose of liftingup a sample of the.soiL, When obtainedthis samplewas divided into two parts,the smallerpart was taken to the laboratoryon board the USS BAIROHD,and the other to Eniwetokwhere it was loaded on aircraftand flown to the S.osAlamos laboratoriesin the United States., The tank was operatedby remote controlfrom a helicopter,after its operationhad been checkedby a ground operator,and it was guided by this means to the craterand return, Ifa for any reason>the helicopter and its standbylost control,the tank operationcouldbe taken over by an auxiliaryset of controlequipent in the IEM which brought the party to the island, The ICMalso carriedanadditionaltankfor use if the firsttankfailed, . The monitorsassignedto this mission on X-F&y'Daywere LCDB Vandergriftand ET, Way, Dr, Bowman,who was in charge of the mission, the drone filterremoval,as the Tank m took off for the test island, The ICM picked up the monitorsfrom the BAIROKOand beachedat the lower end of the islandnot far frcunthe Tank Revetment, No damage had been done to the tank by the blast other than loss of the antenna, This was replaced,the tank was startedand driven out of the revetmentto his arrival at lll0, the tank controllinghelicopterwas calledfrom the jeep to lay out the flag markers,beyond which it would be unsafe for the tank controllinghelicopterto fly0 The tank performedwell, and made two runs with sampleswhich were consideredtoo low in intensity, On the third attemptthe tank was stalledin the craterand co&i not be moved by rem&e control, The reservetank could not be used because it was now minus its radio antennawhich it had sacrificedfor the first tank,

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The first samplewas taken for study,,anddivided, The first part arrivedwith ICDR Vandergriftat the RAIROKOat l,330;-and-the secondarrivedat Rniwetokwith I& Roy by 1'740;The pafiy became contaminatedto some extentand arrangementswere made to clear this party at Eniwetok, The tank controloperatorwas subjectto some exposure,and to proteotthis operationa second helicoptercontaininga monitorw&s dispatchedto accompanyand ranain forwardof the operatingplane, This missionconsistedof the dispatchby helicopter,of members of the l&J=-3 group to the land cable on the test island,in orderto assistin the recoveryof samples, It was essentialthat certainof the sampleson the land cablebe recoveredas quicklyas possiblein order to take proper technical measurements, Nindingthe cable on to the drum of the winch took cqnsiderabletimes and startingthe drum promptlysaved time for theAVR party which later came to the island to completethe c'ollectionof the samples, A monitorwas sent as monitor for this party to accanpanyDr, Ogle and his assistants, The duties of the monitorincludedthe clearing of the landingfor the other helicopters,standingby while-thewinch was started,going foPivardalong the cable in a jeep with Dr, Ogle to recmer samplesnear the zero point and later openingup the cache and startingthe radio communication, Three helicopterswere used, It was found after X-RAY Day that the operationwould be facilitatedif six men were sent in on this On X=RAY Days a monitorclearedthe landingof the other planes, and went to the cachewhere he found the door blcrPvnin and the radio inoperable, Severalof the sampleswere missingfrom the cable as it was wound in, and Dr, Ogle with the monitorwent forwardto locatethese samples, The missionwas accomplishedin less than two hours with very low exposure(200mr) to all personnel, The monitorthen returnedto the AVR and accompaniedanunschtzdaledwater cable party0 No saxzp3.e~~-*- were found eitherafloat or en the bottom of the lagoon,as far as could be seen0 S!WC the party went quite close to the zero point inthewater, considerablymore exposurewas the result0 H~ever, the total received was well within the toleranceestablished,%ore of the missing samples were recoveredin latertrips to the island,

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to date as rqqts came in and an iso-inten&.ty3&1e of.&1 r per day in the lagoonwa%%as al.30 plottedon this chart, The'surfacsand air radexeswere plotteddaiiy from weather data obtaintdfrom Aerologyo Uti&zing a vector analysisof the wind and 30,000 feet were determined, Thesepatternswere plottedon charts with a superimposedpolar gria, From the f&-out patterns,the surface radax,given as two bear-s from nero point, and also recommendations as to the directionof the third pass for each drone plane motherwere Definitecriteriawere used to determinewhether or not the day from 45@0 feet or beluw, did not extendbetween9o"T or 170°T from zero poi.nt,'theday was consideredoperational, If the fall-outfrun the day was~consideredquestionablewith moderatehazard, If the fallout from 35,000 feet or belao fell on these islands,the day was conThreedays precedingthe test a forecastfor a test day was made, and on the day before the test day the latestweatherforecastwas presentedat MOO, Actualwinddatawas plottedat intervalsfromthis time to 0300 at which time the last baloon soundingwas made and the data was preparedfor the briefing, Considerableradioactivitywas found on the islandswest of the elsewherewere sl&ht, A consolzdatedreportwas preparedand a3l the evidencesof fall-outnoted during the days followingthe test, Joint Task Force 7 statingthat the stiey of all the perfmeterislands had been completed,and reccmtnendedthat long term closureof the islands from Yeiriwestward to the southwestpassam inclusivebe instituted becauseof the radioactivitydiscoveredalong the beachesand the evidences lagoonbmrhes on these islandsfor swimmingwas recortznendedO Dust collectorshad been set up on each of the principalships of the Task Force, and were examineddaily8togetherwith a carefulcheck of the evaporatorso Severalsurveyswere made on the test islandand the gradualretreat of the iso-ihtensitylines was plottedin Radop,

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On the fifth day after the test, a guard of two monitors each morningand afternoonwas set up on the test island,and the Beach ~adsafeCenterestablished, This made the islandmore accessibleto the engineerswhowere to work,on..theportionwhere the intensityof radiaticnwas now below tolerancelimits. It considerablyreducedthe monitordemand on Task Group '7&, and at the same time insureda closer watch on the many partiesthat had mission on the test island, The bogged ix&k was recoveredfrom the crater,and work was begun by the engineersto destroythe remainsof the test structureson the islandin order to preventany unauthorizedpersonsfrom obtainingany informationon the effectsof the tests, off the test islandfor YOXE Day0 and final preparationsfor YOKR test werewellunderwayO Two days later the island of X-RAY test was closed to all personnelo Installationof stakes,and the paintingof numberson various structuresof the test islandfacilitatedislandsurveys0 Three stakes at hundredyard intervalswere placed on the islandimmediatelyto the north of the seropointforuse inanysurveys thatmightbe made in this direction, The stakes on the test islandswere not locatedon a systematicradial manner from the zero point as was the case in test X-RAY, because the engineerstructureswere locatedfnaclearedstrip extendingalong the lagoonTide of the islandsand about 300 yards wide, It was plannedto ignore9for all praaticalpurposes, the extensivepalm grove on the ,portionof the islandtuward the ocean,and which was expected to become a mass of tangledrubbleas a result of the test, All of the island surveymonitorswere throughlybriefed,, Becauseof the evidenceof fall-outfrom the X-RAY teat, it was decidedby higherauthorityto maintainmonitors‘onthe destroyerpatrols untilYoxE-plus40 Accordinglya monitorwas assignedto each of following A huge cloud resultingfrcm the exptisionof the atanicweapon was still plainly&dent thousandsof feet above the zero islandwhen the four helicopters-came in on the southerntip of the island for a landing, The landingwas made about twentyminutesafter H hour, Major Coo? in a jeep with Dr, Ogle a-d Mr, Ldnnenbergerwent along the land cable to assist in recoveringthe samplesat variouspaints along it, Major Sheppard

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stayedwith the rminder of the party in the "tricinityof thc.wd&h, All but lO0 ms*8?the cable was recoveredwith all of the samples excepttwo of the multiplesamples. The winch and cable remainedcool (50 mr) duringmore than half of the operation,and then began to get rapidlyhigher intensitiesuntil it reached 15,000mr at six inches. A piece of metal, supposedlya link from the tower cablewas found near the winch testinghigherthan 5,ooOmr, This materialwas removedto c safe distancefran the operation, Major Cook ttrossedthe causeway,i: with Dr, Ogle, approachingthe zero point to a readingof 20,000mr/hr and returned, The missionwas entirelysuccessful,all members of the party takingproper precautionsin harxWng the sampleswith gloves and tongs, and no overaqxxurcs were obtained, copters9beachingon the islandby an ICVP that had been picked up by wedged and the party at this stationreceivedsome contaminationon their clothingwhile forcingan entrance, A cameraplaced onthe causewaywas All of the personnelreturnedon the AVR 38, and were checked for contaminationon boardingthe USS BAIROKO, Meanwhilethe sampleshad been flown by helicopterto the laboratorieson the USS AlBEWRIE for final analyses, The entire operationwas completedearlierand more efficiently than in test X-RAY, Follcwingthe test, the USS BAIEQKOweighedanchorand was proceeding slowly to its anchorageoff the test island,precededby four boats patrow the lagoonwaters ahead of the ship, Two otherboats preceded the rest of the JTF 7 fleet to their anchorageoff the islandto be used for test ZEBRA, These boats were trackedand plottedby radar and the readingsof radiationintensitiesin the water were transmittedin code to the Padsafe Centerand to Radops on the BAIROKO, Isa-intensitylines of water contsminationin the lagoonbetweenthe anchorageand the test islandswere plottedfor the informxtionof the Task ForceRadiological The backgroundcount of radioactivityon the bridge of the USS BAIROKObegan to raise noticeablyimmediatelyfolJ.owingthe test, but the amountwas not alarmingand it was decidednot to changethe anchorage. This increasein backgroundwas also observedat the same tdmc on Parry The survey of the test craterfrom the air was begun by ICDR King in a C-47, but he was forced to turn back when his plane receivedso much fall-outfrom the cloud that the readdngsin the plane began exceeding the daily tolerance,

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'At H-plus3 hours two monitorsboarded the Tank IQd as it came by the BAIROKOand proceededto the zero islandto await Dr, Bowman who was to fly to the islandby helicopterafter supervisingthe removal of filtersfrom the drone planes at Enixetok, Dr, Bowman arrivedat l.050, and flagswere placedat the center of the causewaymarking the limit of safetyfor the tank controllinghelicopter, The helicopterin which the tank operator,was ridingwas forced down by engine troubleon another island,and causedsome delay before he couldbe flown in for the operation, At IL30 the operationwas ready, The tank that had bean stationedin the revetmentduring the test was drivenmanual3yto the causeway,and from thenceproceededunder remote controloperationto.the crater formedby the test weapon0 The tank soon becamebogged down, and effortsto get it startedagain were unavailing.‘The reservetank that had been broughtup in the,ICM was then sent in and successfullyobtaineda soil sample from the desiredpoint,returningto the uncontaminatedand of the island, This soil samplewas divided,a small portionbeing sent to the laboratories on the USS BAIEUXO,and the remainderbeing taken to ELwetok by one of the monitors. This lattersample reachedEniwetokby 1510 and was dispatched by air to laboratoriesin the United States. During this entireoperationa standbyhelicopterwith a monitor took up a positionnear the tank controllinghelicopter,in order to insure landedto investigatethe troublewith the tank, the monitor in the other hslfcoptercheckedmost of the islandat an altitudeof 500 feet, except that portionin the vicinityof the zero point., The evaporatorson the BAIFtOKO.andon for radioactivityand found satisfactory, The northeastperimetersurvey of the 0930 in two dukws, ESrtensiveevidenceof fall-outzas found on all the islandsof this section, A detailedsurveywas impracticablewithin the restrictionsof a routinemission,and readingshad to be taken while moving rapidlyalong the beaches in the dukws. Only tilf of the islands plannedfor survey'couldbe covered before tolerancedoses had been_ receivedby all personnel, Some evidenceof water contamination was observed,and all resultswere reportedin detail to F&dopswhere a At about d0 hours the backgroundon the flight deck and hanger deck of the USS BAIROKObegan to noticeablyincrease, and it shortly became evidentthat appreciablefall-outwas occurdngon the ship, About the same tdme, it was reportedthat fall-outhad occuredon Wjalein,, and stepswere taken to fly water samplesto t3e 'Laboratorieson the MIROKO for study. Hourly samplesof filterpapers from the dust collectorswere taken

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throughoutthe day, and studiesof beta countmade in the laboratory, a cascade5mp&cto2Mas operatedat the same time, …