DECLASSIFIED a Authorin gegfg A or MEETING or EVALUATION COMMISSION roe ATOMIC BOMB TESTS AND THE STAFF OF COMMAFDER JOINT TASK FORCE ONE HELD IN NAVY DEPARTMENT WASHINGTON D C AT 0950 ON SATURDAY 50 MARCH 1946 PRESENT The President s Evaluation a Representative Walter G Andrews Commission Dr arl T Compton Senator Carl A Hatch RepresentatiVe Andrew J May Mr W S Newell DP J R Oppenheimer Senator Leverett Saltonstall Mr Fred Searles Jr Joint Task Force ONE Vice Admiral W H P Blandy Commo J A Snackenberg Bean Adm W S Parsons Z gag Sen A L McAuliffc Re Adm T A Solbergx Rear Adm F J Lowry Brig Gen T S Power Brig Gen T J Bette g gt e Dr R A Sawyer Dr J Von Neumann Dr D Z Bechler Col J D Frederick Capt R S Quachenbush Col D S Blakelock Capt L A Kniskern Capt K Lyman Capt H Rivers Col W D Ganey Col H B Smith Capt S Brodie Capt H R Carson Capt A A Cumberledge G Li Capt P Foley Aanhattan Engineer Dist a Maj Gen L R Groves Col H C Gee Lt Col J A Derry t Adm Blandy Opened the meeting by stating that he had suggested the meeting in order to acquaint the President s Evaluation mission with the plans and preparations for the test and to answer any questions that the Commission might desire to ads He suggested that a chairman be appointed so that he could address correspondence for the Commission to one person He also stated that he would appoint one or more officers to act as secretaries to the Commission of they so desire 9' DECLASSIFIED Authority 770 Adm Blenly described the origin of the atomic bomb tests which began with a request from Gen Arnold of the Army Air Forces to the Joint Chiefs of Staff suggesting that the battleship NAGATO oe as target for atomic bomb tests by the air Force which request vas closely followed by a preposal from Fleet Admiral King to the effect that a number of Naval vessels be used in a test of atomic bombs - 5 Adm Blandy then read the directive to him from the Joint Chiefs of Staff which was issued on ll January and-contained the general purposes and requirements of the test and which authorized him to deal directly with the various military and naval agencies involved in the test Adm Blandy then proceeded to describe the organization of the Joint Task Force staff and gave the duties of the various members 0 the staff pointing out the participation of both Wavy and Army members as well as civilians in the higher echelons He then went over the chart showing the organization of the Te Force into Task Groups and explained the function of each of these Task droups 5 Following this Adm Blandy mentioned the reason for placing Army equipment on the dechs of the ships under test and stated that the great distance of the detonation from the nearest shore made it desirable that the Army ground equipment be exposed on the ships rather than on shore 6 He then discussed the function of the drones to be used in the Operation Both Army and Navy drones will be used to obtain samples of the air after the eXplosion to assist in determining measurement of bomb efficiency He also mentioned the plans for use of a sea plane unit and a destroyer squadron to follow the contamie nated area of water after each test 7 Adm Blandy explained that no personnel will be in the Bikini Atoll at the time of the test the natives of Bikini having been evacuated to Rongerih prior to the test He then went over the organization of the technical staff and mentioned the duties of the Technical Director Dr Sawyer the Director of Ship Mat rial Rear Adm T a Solberg the Safety Adviser Capt Lyon and the Radiological Safety Adviser Col Warren factors which resulted in the selection 8 Adm Blandy listed the as follows of Bikini for the tests l Its remoteness from inhabited areas 2 Freedom from storms 5 Anchorage of sufficient size a Favorable wind and ocean current conditions He showed the location of Bikini in the Marsralls area and indicated the distances from various importalt bases as stated that the island of 7 Ujelang is uninhabited and that Eniwetoh which is to the west of Bikini will have to be temporarily evacuated for the tests in view of possibility of contamination either from airworm waterwcarried radioactivitV as then gave a 'ist of the ships 2 DECLASSIFIED Authority 3770 _gi l 0t d as tavgets for the tests as-follows 5 battleships e cruisers 2 carriers 17 8 submarines 25 merchant type vessels 1 concrete drydoch 2 concrete barges 25 LGT's 6 LOI's 6 LST's l2 small boats In answer to a question from Mr Searles as_to how the total number had been determined he stated that the Joint Chiefs of Staff had directed the use of representative ships of various types'and sufficient numbers to give the preper gradation of damage Additional ships are used to carry instruments 9 - Adm Blandy then read the plan for the operation which he had submitted to the Joint Chiefs of Staff and stated that all major features had been approved by the Joint Chiefs of Staff and that he had consulted both the armed services and the scientists as to these major features before submitting the plan for approval The Fish and Wild Life Service cf the Department of Interior has also given its approval to the location for the tests 10 He stated that animals are being used on some of the ships to test biological effects of the bomb and that although protests had been received on the use of animals the lcision has been made to use them because scientists have insisted that this biological information cannot be obtained by alone ' This data is of great importance to the military me 1 for protection of our men and-will a so furnish information of value to scientists in general ll Adm Blandy went over the schedule of the tests as at present set up which includes the target date for the first test air drop from a as 1 July and the second test with the bomb either on surface or under water to take place abcu three weeks after the test the exact date dependina on the results of 541M the first t e stated that the underwater hot for the second test will greater effect ships he the giving neat data for the a which indicates that seven days tab er 1 53 -v showed a chart It in July and eight days in will be sui ls for air operations seven days in July and twelve days in August questionable and the others Will be unsatisfactory 12 Representative Andrews inquired as to the plans for the iommission while they wait for the second test and Adm Blandy stated that there will be no time to return the ships to the mainland oetween tests but that arrangements will be made for a brief cruise to some of the more interesting places in the irea such as Teresa Guam Saipan etc l5 Admo Blandy then explained the reasons why tLe third or deep vater test could not be held this year namely the great difficulty in completing the proper design in ti for the test is also mentioned the great latitude given to civilian scientists in the planning and execution of the tests and stated that the survey vessel party now in the area includes hydrographors cean igraphers biologists and geologists who are out there obtaining important scientific information 5 Adm Blandy mentioned the participation of foreigners as rservers in the tests and stated that invitations for the foreign pobservers are now in the hands of the state Department These observers include two representatives from each of the nations who are members of the CWO Atomic Energy Commission and in addition eight additional from England and four-from Canada that there will be press representatives and gho are being selected by Dr Jewett of the Ne ional Academy of clones He stated also a number of scientists 15 Ads Blandy then went over the target array for the air bunst mentioned-the security classification of the exact arra secret as are also the details of measurements and of damage lb Senator Est rmation is secret and Adm Blandy stated that the exact bombing altitUde exact and the details of tie bomb are highly secret Adm Blandy explained the reasons tie array are very close together blast pressure drops off rather that it is desired to allow for pOSw re that the bomb will burst near at 17 In going over the array why ships near the center of which are l the fact that tn quickly with distance and 2 sible bombing errors and ins least one large ship 'by the Joint Chiefs of Staff 18 He then described the distriiution of fuel and ammunition in the Tarious ships and stated that an attempt was made to represent practical war conditions at an anchorate He stated that burning oil would be the worst hazard for secondary fires The amount of oil in the ships near the center has been decreased centage of the normal ammunition although they have a high per 1 19 Representative May inquired whether the explosion of this ammunition would cause confusion in the results Adm Blandy stated that he felt enough information will be obtained under the proposed conditions and that war experience such as the explosion of the Mt Hood indicated that explosions in one ship are not too damaging to other ships in the vicinity The'hazard of burning fuel in the wrter is serious and for this reason the ships to windward have been loaded with a lesser amount of fuel oil than those to leeward 20 idm Blandy then went over the target array fer the second shot ant stated that although final approval had not been given by the Joint Chiefs of Staff they had given tentative approval and that the array was subject to revision after the first test He 1 stated that he intends to submit a plan to the Joint chiefs of Staff for approval in case that it is necessary to eliminate the a drop test Dr Compton inquired if minor changes could be made after Test air drop and Adm Blandy answered in the affirmative Senator Saltonstall inquired as to the use of various orientations of the various ships and Adm Blandy replied that an attempt was made within the limitation of practical seamanship to obtain both bow on and beam on presentation of the various ships although this is not practicable among the ships that are very close in because of the difficulty ineplanting le necessary moorings the effect is a He stated that this array had been approved as being top ch requested that the Commission be told what infoe height of burst the exact depth for the second test ir Mi @1011an a DECLASSIFIED Authority '770 I w 3% ained in some cases by having two lines of the same type on different bearing from the point of detonation Senator Saltonstall also inquired as to why not have some ships with no ammunition Adm Blandy stated this would be desirable if we had enough ships of each type to give a good comparison but that the array has had to be a compromise between realism and technical factors and no ammunition condition-is approximated in the case of some ships which have a minimum amount on board Bl Adm Blandy then proceeded to state the information which the servicesdesire to obtain from these tests He stated tiat the material bureaus in the Navy are interested in obtaining information to assist them in designing ships and equipment the tacticia d are interested in information regarding the effect on naval formations and the strategists want to know the effect of the bombs on the disposition of bases and fleets The Army Air Forces wish to know the value of naval vessels as targets under various conditions and the Army Ground Forces want to know the effect of the bomb on the various types of equipment ve May inquired 'f there were encugh Japanese rgets for the test Adm Blandy stated that very ew ships we serviceable that the Negato and Sahawa are being used and that we available submarines of modern construction are being saved for other studies and are not being used in the atomic bomb tests 22 Represents as i ships to use a or Jatch inquired whether Adm Blandy had discussed the L4 apprOpriate mmittees of the House and Senate and he this should be done since there exists some misunder he purposes of the test Adm Blandy stated he had House and Senate val Affairs Gom discussed lans with tn are a technical mittees and test and no Ta -aid he wished to emphasize the emonstration of power 24 adm Blandy then explained the need for a rehearsal and briefly described the plan for evacuation of the lagoon before the test He also stated that the MT MCKINLEY and one instrumentation ship would be about ten miles from the lagoon during the test and that all other ships would be no closer than twenty miles 25 Adm Parsons then discussed the technical aspects of the operation and gave as the item of highest priority the measurement of the bomb as a nuclear fission bomb He stated that there are many unknown factors regarding this type of bomb and it is important that exact information regarding its efficiency be determined He then stated that as an item of secondary priority is the determina tion of the eXplosive efficiency of the bomb as a blast engine 'He stated that the effect on ships cannot be predicted without actually molding the test Dr Oppenheimer inquirei whether the information could not be otained from model tests Adm Parsons and Capt Knishern stated that the complicated structure and the stiffness of the ships were factors which could not be properly duplicated in odelS Dr Op enheimer suggested that the reliability of model tests could be estimated after the atomic bomb tests Adm Parson stressed the fact the the ships must be treated as deformable Oodies rather than rigid bodies as is the practice with model tests as e - DECLASSIFIED 1 Authorlty 87701 I d that there is great difficulty in scaling all the various _gactors affecting the results Adm Solberg agreed that we need-v fame results of a full scale test before model tests can be used 26 Adm Parsons described the plan for exposing equipment including tanks airplanes etc on the target ships and also electronic recording instruments graphic recording instruments and simple medhanical instruments sucn as oil drums which will give good measurements of pressure because of the long duration of the pressure pulse 37 eds Solberg went-over the problems of the Director of Ship Material including the preparation of the ships insuring proper water tight integrity the coordination of the test requirements of Army and Navy activities the problem of inspection after the test and the complex instrumentation installation including instrument design and training of personnel He stated that his organization is ready to go ahead with the tests as planned 28 Adm Parsons went on to explain that the atomic bomb differs from conventional explosives not only in the order of magnitude of the heat energy but also in the radioactivity effects In view of the great heat intensity any plan to test ships as inert targets without fuel or ammunition would be artificial since the behavior of the ships under norsal cond'tions of loading When subjected to the extreme pressure and heat would be different from that of ships not carrying that load 29 Dr Sawyer briefly discussed the instrumentation and stated that the details of instrumentation the exact disposition of ins truments and the data of the instruments will be highly classified He stated that details are described in the instrumentation annex which will be available to the Commission He mentioned the remote measurements that will be made to determine what effects of the atomic bomb can be measured at great distances from the explosion and also mentioned the other types of measurements to be made at the location of the test He also stated that it is difficult to predict the effects of the explosion f-om the brief data on the earlier bombs and also that no one knows how much under water-shock is required to destroy a ship 50 Sept Lyon the Safety Adviser described briefly the plans for insuring safety both from radiological danger and from more conventional dangers such as fire fumes and explosions He went over the general plan for safety reconnaissance and monitoring of hazardous areas before approaching the target ships after the tests and the continuance of monitoring as long as hazards exist in the area including the tracing of the contaminated water and air in the vicinity of the blast he stated that special glasses will be required to be worn by all observers and that these glasses will be provided in adequate numbers 51 den Groves then mentioned that he advocated the presence of large quantities of ammunition and fuel on board ships but Authority i kw agreed to reduce the amount from full because of the all evidence due to secondary damage inasmuch as no men will be on board the target ships to fight fires during the test He stated that the distant measurements to be made were to be considered very secret as would also all data regarding the bembs he also stated the effect on the Manhattan Engineering District of the postpon nent of the test and emphasized that if the test is again postponed it will be impossible to carry it out due to the fact that he will not be able to furnish the proper scienw tific assistance ytfhat he had iianger of destroying 52 Adm Blandy said that he would arrang- air transportation for those members of the Commission requiring it and stated that it will not be necessary for the Committee to leave the mainland earlier than the 25th of June if they go by air Senator Hatch requested Ade Blandy to work out a schedule for the Commission to include dates of departure and return to the U S 55 Representative Andrews stated that there is opposition to the ideas of the tests in certain quarters and that it would seem advisable to publicize the tests and sujgest that perhaps the Joint Chiefs of Staff should make some relerse indicating the importance of the test 54 Senator Hatch stated that he has heen inferred by Senator 3 Walsh that unless the Joint Chiefs of Staff feel there is an overwhelming reason for holding the tests he Senator Walsh would favor calling them eff and he stated that so far no such overwhelming reason had been advanced asked Adm Blaidy if he could make Chiefs of Ste and Ada Blandy leases in behalf of the Joint and what 55 Te Andrews Representat of the Joint a release in bed stated is had alr Chiefs of Staff would be gained several What the tests i would consist of 56 Mr Nowell stated that from the shipbuilders point of view there are overwielning rcrsons why the tests should be held He stated that it would be impossible to design ships against atomic warfare without the hind of knowledge ereectcd to be obtained from the test 57 Representative Andrews stated that should tell the president of the Senate and the Speaker of the House the overwhelming reason for holding the tests Senator Hatch stated that since there is so much wrong information out on weat can be obtained from the tests there should be some positive explanation given to the public the Joint Chiefs of Staff 58 r Compton stated that evidence at Hiroshima show physical effects which could not be'anticipt results of the New Hexico exioriment also that i under water will produce_defferent effects from and that the bomb is still eiperieental and Nagasani from the explosion so over land munm I DECLASSIFIED Authority 770 Gen Groves stated that from the Army standpoint it would be important to have the Joint Chiefs of Staff issue a statement along the lines suggested by Representative Andrews Gen Groves also stated that he understood the fact that we are using all these ships as targets will not prevent us from obtaining data applicable to-design of new ships Adm Solberg confirmed his view and stated that certain caisson tests held at Norfolk showed that new design can be improved from properly instrumented esperiments 40 Col Blaheloeh gave a brief resume of the shore contruction activities in Bikini Atoll Capt Quachenbush then gave a summary of the photographic program including photographs by Army and Navy aircraft both movie and still also photographs from towers on the atoll and photographs from the ships He stated that the photo graphic program involves-about 20 airplanes and 500 photographers 41 Adm 'Blandy then stated the effect that postponement would have on Navy peesonnel He sta ed that 1 September is the deadline for demobilization of the Navy and that personnel used after that date must volunteer if they were eligible for release He also stated that the ta get ships being used except for the five heavy hull submarines and the IEDEPERDENCE were already slated for diSposal 42 The President s Evaluation Commission and Joint Task Force staff then proceeded to the air operations war room for briefing on the air operations plan First Gen Mciuliff described the participation of the Army ground forces whose part is to display representative Army equipment and to analyze the effect of the bomb on it 43 Gen Power ass'sted by Col Ganey and Capt Foley wont ever the complete plan of air-operations for Day the day of the first test and stated that except for the presence of the bombing planes the air plan for the second test would be essentially the same 12 Horacio Rivero Captejsn TJSN