Operation Hardtack - Radiological Safety - Report to the Scientific Director

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Report to the Scientific Director Los Alamos Scientific Laboratory — Los Alamos, New Mexico

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This report contains a description of the mission, organization and activities of Task Unit 6, Task Group 7.1, Joint Task Force SEVEN, during Operation Hardtack. Task Unit 6 was charged with the responsibility of providing radiolo~cal safety support for the Scientific Task Group, TG 7.1. The various chapters are devoted to a discussion of the activities engaged in by the Task Unit and the organization necessary to provide adequate radiological safety support for a weapons test operation of the magnitude of Operation Hardtack. Radiological survey results of the atolls following firing of the various devices are presented. Special problems arising during the operation are discussed.

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Task Unit 6 (TU-6) wishes to aclmowledge the cooperation and support of the following organizations. Their combined efforts were largely responsible for the success of the radiological safety operations during Operation Health Division, Los Alamos Scientific Laboratory (LASL) . Supply and Property Department, LASL Albuquerque Operations Office, Atomic Energy Commission (AEC) Holmes and Narver, Inc. (H&N), Los Angeles, Calif. Office of the Chief Chemical Officer, Washington, D. C. U. S, Army First Radiological Safety Support Unit, Chemical International Business Machines Corporation (IBM), Albuquerque, New Mexico, and Birmingham, Ala. In addition, the following individuals are to be credited with making significant Contributions t~t ~terially assisted TU-6 during all phases of Thomas L. Shipman, Health Division, LASL William E. Nolan, Health Physics Group, University of California Simon Shlaer, Health Division, LASL

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Procurement of Personnel Training of Personnel Facilities and Services Shots and Survey Results Film Processing and Record Posting Chapter 2 Eniwetok Operations 2.1 – Cactus Radiation Intensities

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2.2– Butternut Radiation Intensities 2.3 – Koa Radiation Intensities 2.5 – Yellowwood Radiation Intensities 2.6 – Magnolia Radiation Intensitiess 2.7 – Tobacco Radiation Intensities 2.8 – Rose Radiation Intensities 2.10 – Linden Radiation Intensities 2. 11– Elder Radiation Intensities 2. 12– Oak Radiation Intensities 2. 14– Dogwood Radiation Intensities 2.15 – Pisonia Radiation Intensities 2.16 – Olive Radiation Intensities 2.17– Pine Radiation Intensities Chapter 3 Bikini Operations 3.1 – Fir Radiation Intensities 3.2 – Nutmeg Radiation Intensities 3.3 – Sycamore Radiation Intensities 3.4 – Maple Radiation Intensities 3.6 – Redwood Radiation Intensities 3.7– Hickory Radiation Intensities 3.8 – Cedar Radiation Intensities 3.9 – Poplar Radiation Intensities 3.10 – Juniper Radiation Intensities Chapter 2 Eniwetok Operations 2.1 – Firing Schedule, Eniwetok Atoll Clmpter 3 Bikini Operations 3.1- Firing Schedule, Bikini Atoll

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The mission of TU-6 was as follows: a. Perform all ground and aerial monitoring services associated ti the scientific mission except those in conjunction with aircraft and airborr collection of scientific data; assist TG 7.5 radiological safety (rad-safe) o: ganization during the operational phase. b. Provide laboratory and technical assistance to all task groups. c. Provide all official personnel dosimetry services for Joint Task d. Issue and maintain monitoring instruments and protective clothin e. Supply decontamination facilities for personnel, vehicles, and eq~ The operational concepts, calling for firing capabilities at both Bikin and Eniwetok atolls, demanded a Task Unit organization that provided two separate and independent rad-safe groups. Accordingly, separate organiza tions were established at Bikini and Eniwetok with over-all cent rol being m tained by the Commander of TU-6 (cTu-6). The organization at each atol was similar, varying only with the number of personnel assigned to the va ious sections. Each organization contained the following sections, as show in the organization chart in Fig. 1.1: a. Dosimetry and Records Section for maintaining personnel dosime b. Plotting and Briefing Section for conducting all radiological SUI%’

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and briefing all personnel going into radiological exclusion areas (radex). c. Monitor Section for providing all monitoring services and mmmir d. Supply Section for providing rad-safe supplies and laundry servic e. Decontamination Section for operating facilities for personnel and f. Instrument Repair Section for maintaining rad-safe instruments. g{ Laboratory Section for determining the amount of radioactivity in soil, water, air, and food samples. At the start of the operation the Eniwetok organization strength was i that at Bikini, 45. The total was later reduced to 78. All supply problem were handled through J-4, located at Eniwetok. The master files of photodosimetry records were maintained at Eniwetok and the film badges issued the Eniwetok Dosimetry and Records Section. Responsibility for radiological safety for TG 7.5 personnel was not a function of TU-6 during Hardtack, in contrast with past operations. Howev H&N rad-safe personnel were utilized within the TU-6 organization and rad safe support for both TG 7.1 and TG 7.5 was provided by the Task Unit. 1.3 Procurement of Personnel Personnel for manning Tu-6 were obtained Air Force. The majority was obtained from the Corps unit stationed at Ft. McClellan, Alabama. * down of the total personnel utilized by TU-6: a. Army -- 95 officers and enlisted men. b. Navy -- 8 officers and enlisted men. from the Army, Navy, anc First RSSU, a Chemical The following is a breakC. Air Force -- 12 officers and enlisted men. d. IASL -- 4 civilian health physicists as advisors. e. UCRL -- 3 civilian health physicists as advisors. 1.4 Training of Personnel . Training of TU-6 personnel was carried out in several places. The majority of the First RSSU personnel received training at Ft. McClellan, ~ Alabama, the unit providing its own training staff. Approximately 40 members of the First RSSU participated as trainees in Operation Plumbbob at ‘ the Nevada Test Site with the Reynolds Electric and Engineering Co. rad-sa group. Instrument repair personnel received extensive training at the Navy

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at the Navy facility at Treasure Island, San Francisco, Calif., and at LASL. The four Navy hospital corpsmen who provided the bulk of the laboratory services were trained by LASL Health Division personnel. Dosimetry and Records personnel received extensive training in the use of IBM equipment at Ft. }lc Clellan, Ala. This training was conducted by the Birmingham, Ala., office of IBM, Scientific project personnel in TG 7.1 and contractor personnel in TG 7.5 were requested to provide their own monitors for recovery and construction missions. A four islands specifically to train approximately seven weeks. trained at the school. day school was operated at Parry and Enyu such monitors. The school was in session for Personnel from TG 7.3 and TG 7.4 were also

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2.1 Facilities and Services In support of the operations at Eniwetok Atoll, check points controlli entry and exit from contaminated areas were established under the directi of the Operation Section of the Rad-Safe Center as required. Main check points utilized at all times were located at the air dispatcher’s office and the marine landing. As the situation demanded, other check points were e tablished at the personnel pier and on islands in the atoll other than Parq All persons entering or returning from a radex area were processed thro~ these check points. An area was considered a full radex area if the contamination exceeded 100 mr/hr and full protective clothing was required fc entry into it. Limited radex areas were established as necessary where f contamination was in excess of 10 mr/hr but less than 100 mr/hr. In the areas the clothing requirements were dictated by the situation and the job be performed. In those cases in which alpha contamination presented a pr lem, no hard and fast rule concerning full radex areas was established. G erally speaking, a contamination level of 1,000 counts per minute on the ~ Eberline PAC 3G alpha meter indicated that fuU protective clothing should 1 used; however, the type of work to be done in the contaminated area was O considerable importance in establishing clothing requirements. 2.1. 1– Personnel decontamination facilities were located across the S; from the Rad-Safe Building, as they were during Operation Redwing. The ; facilities consisted of clean and “hot” change areas and showers. A total ! approximately 6,200 individuals were processed through the Eniwe~ok check” points from 1 May to 20 Au@st 1958. of these, 860 were processed throul the personnel decontamination stat ion. Laundry services necessary to nd~ tain the protective clothing were provided by H&N under the direction of. thl Supply Section of the Rad-Safe Center. -4

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,nd the job to area was Of For the Quince and Fig events it was necessary to establish a personnel decontamimtion station on Runit. The traffic through this decontamination =tztion was very heavy and clothing requirements were such that it was nec - ~ssarv to move the laundry barge from Bikini to handle the laundry load.. si~ce the primary problem was : !-e clothing had to be disposed ~ie contamination to acceptable .;isposed of in many cases. one of alpha contamination, a large part of of because it was found too difficult to reduce levels. Respirators and full face masks were surgeon caps, gloves, and coveralls had to be 2.1.2– The equipment decontamination station on Parry Island processed I total of 800 items, including 56 vehicles and 9 helicopters. Numerous ~icces of small equipment were cleaned up for the various projects and for I!&N. Normal procedure called for all heavy equipment returning from shot :slmds to be monitored on removal from boats and directed to the decontami-. ~ation station if necessary. Versene and citric acid were the common decon- :.~min~ting agents employed, and a steam generator was used to provide hot <olutions for the necessary washing. When equipment was not needed immei!:ltely it was held in a ?thot~~parking lot for varying len~hs Of time before ~ccontamimtion in order to reduce contamination levels by radioactive decay 2.1 .3—The Operations Section of the Rad-Safe Center was responsible : )r the conduct of all radiological surveys on the atoll, the majority of which :ere made by H-19 helicopters. H-21 helicopters were not used for survey ;’~rToses since the possibility of excessive crew dosage was always present (:UCto the configuration of the aircraft. In contrast to the H-19, where the ;-iiot’s compartment was located above the engine, the H-21 provided no ~h!clding at all for the flight crew since the pilot fs compartment was simply I p!xstic bubble on the nose of the plane. !lilcd survey of the entire atoll at H+6 to H+8 hr, and detailed surveys on ~S required. The basic instrument used in the aerial surveys was the “~~ ‘p DR-39 survey meter modified to read up to 500 r/hr. The logarithmic “~le instrument built by Jordan Electronics, Inc., that proved so successful ‘n %~tion Redwing could not be made to operate properly and so it was r.cVcr used, When necessa~, data were radioed back to the Rad-Safe Center ‘rem the sumey helicopter by means of the helicopter radio net. Plotting 2M briefing stations were maintained at the Rad-Safe Center and the J-3 O!f!cc. Ground surveys of islands in the atoll were conducted when required. The helicopter survey technique called for the pilot either to land the 2i‘cr~ft at the desired spot SO that a ground reading could be obtained or to ‘-~~~ a SlOWpass over the desired spot at an elevation of 25 feet. Readings

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taken at 25 feet were multiplied by a factor of 2 in order to obtain a reasonable approximation of the true ground reading. The factor of 2 was expe rimentally determined and checked at various times during the operation. Experience indicated further that any reading taken from an altitude of 50 feet or higher was extremely clifficult to correct to true ground values due to the asymmetry in the radiation fields and the topography of the various islands. 2.1.4- Monitors for recovery parties were provided by TU-6 when necessary. Demand was quite small except for the Quince snd Fig events when 28 TU-6 monitors were used. ~ general, however, projects provided their own monitors as members of the recovery party. Monitors were responsible to the party leaders, who were expected to accept a monitor’s advice and plan their operations accordingly. 2.1.5- Laboratory facilities at Eniwetok for radiochemistry work were obtained from the U, S. Army Signal Corps. The AN/MDQ-l radiochemistry laboratory trailer was parked near the Rad-Safe Building and used for aH sample preparation and counting. Approximately 450 water, food, and soil samples were processed and counted. Primary interest was centered in gross beta-gamma activity or total alpha activity. No detailed radiochemistry studies were required or attempted. In addition, numerous air filter samples were counted for alpha activity following the Quince event. 2.2 Shots and Survey Results In the course of the operation, contamination from any one shot did not materially interfere with preparations for subsequent events. This was due in large part to the fact that most of the devices were fired on barges seve ral hundred yards off shore rather than on the surface of an island or on towers. In comparison with Operation Redwing, on-site contamination during Hardtack was remarkably light. Fall-out from the Fir event on Bikini contributed approximately 1,200 to 1,500 mr total dose to those living at Eniwetok Atoll but this did not interfere with any Eniwetok operations. Close rad-safe control over accumulated dosages was effective in countering the dosage received from the Fir fall-out. Very little decontamination of land areas was required since the contamination levels at critical stations were generally quite low. The alpha contamination resulting from the Quince event required very close control and considerable decontamination effort at the zero site in : order that preparation for the Fig event could proceed. Table 2,1 gives a summary of the various events at Eniwetok Atoll. ~ The H+4 hr survey results are indexed by figure number in Table 2.1. i

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s due to lthe jland or on 1 ing at Eniwetok 3 zero site in TABLE 2.1- FIRING SCHEDULE, ENfWETOK ATOLL It is to be noted from the various surVey ‘n ~’~~ckreceived considerable fall-out from the several events at Runit. results that the photo tower ‘c combination of barge zero sites coupled with the normal wind conditions ‘lPP~mntly resulted in continual Contamination of the photo tower. This WIS

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in marked contrast to previous operations. The photo tower, to all intent~’ and purposes, was of no use during the Hardtack events. r. The two underwater shots introduced complications in obtaining the de, sired contamination information. On the Wahoo shot the monitoring was d from a Navy seagoing tug (ATF). Surface contamination was somewhat I@ so the time delay in reaching the target ships was considerable. The tug ~ aIso used for obtaining a water sample for radiochemistry yield determinate”- This operation proved quite successful in that a useful sample was obtained,’ without contaminating the ship significantly and with no more than 1 r toti dose received by anyone engaged in the sampling operation. For the Umbre event landing craft (LCM) from the H&N boat pool were used for the moni~ toring operation with considerable success. Surface contamination was quite low (highest reading observed was 5 r/hr), and within 90 min following det nation all target ships had been monitored and recovery operations were p”. ceeding. A Navy seagoing tug was once again used for water sampling wit out trouble. The tug obtained the water sample at …