Evaluation of Enewetak Radioactivity Containment

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Evaluation of Enewetak National Research Council, Washington, DC Defence Nuclear Agency, Washington, DC

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NOTKE: Tho project that ia the subject of this report waa a * ro&d by the Governing Board of the National Research ColWcil, wt.JaE ~s are drawn from the COuncilu of the National tiemy of Scienc ts, tbe National Academy of Engineering, and the Instituteof Medicin!). The members of the comittee responsible for the re~rt were chos (m fix their special qtences and with regard for appropriate bali ,11~. ‘rtiis report has been reviewed by l group other then the a according to procedures approved by a Report ~iew ~ittee ting of members of the National ~demg of Sciences, the Nati Academy of engineering, and the Instituteof Nadicine. ‘WE NATIONAL RESEARCHCOUNCIL was aatabliabedby the Nati(d Academy of Sciences in 1916 to associate the broad ~nity cf sci~e and technology with the Aca~emy’s pu~e of furthering knowl~dge and of advising the federal government. ‘f33eCouncil operates in w i*A general policies determined by the Acadq under the au its Congressionalcharter of 1863, which establishesthe Acad has becoae the principal operating agemcy of both the Mationa: Acmdw of Sciences and the National Acadw of ~gineering in the corduct of their services to the gwernment, the pblic, and the scienti engineering couazunities. It is administeredjointly by both and the Institute of Medicine. The National Academy of Engin the Institute of Medicine were established in 1964 and 1970, zeapectively, under the charta of the National.Academyof Sciences. THE COMMISSION ON SOCIOTECENICAL BYBTR4B is one of the ma r components of the Nations& Research Council and has general res Sibf.lity for the cognizance over those program areas concernedwith ph ical, technological,and i~dustrial systems that are or may be depl ad in the public or private sector to serve societal needs. THE ADVISORY BOARD OH THE BUXLT ENVTRONNENTis that unit the Cormaisaionon Sociotechnical Systems which focuseson those s er~tific and technologicalissues that are critical to tbe lmprwement f national policies and programs for the built environment. TMs report was prepared under contract number DNAO02-80-C-001 the National Academy of Sciences and tbe Defense Nuciear Agent Rx information regarding this docuee Advisory Board on the Built Environment, National Research Cou cil.

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Chapter 1--SQNMARY AND CONCLUSIONS Nature of tbe Islands The Rmwetak people Location of the contamination Nature of the Problem Safety of Operators Filling of the crater The Drilling Program

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Camittee on Evaluation of Znewatak Advisory Board on the Built ~vironmexk National Research Ouncil

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Evaluationof Enewetak RadioactivityContainment March Evaluation of Enewetak RadioactivityContainment National Research Council I Advisory Board on the Built Environment llLDefense Nuclear Agency Between 1948 and 1958 the Enewetak Atoll in the Marshall Islands w nuclear explosions,part of the government’snuclear testing program. demands of the Enewetak people, the government in 1972 decided to rehab In the cleanup process, radiologicallycontaminatedsoil and debris frc atoll’s <:;landswere placed in a massive, domed concrete containment st one of the bomb craters on Runit Island. In order to provide the peopl the MarshalleseCoverrment with an objective assessment of the nontainn safety, the Defense Nuclear Agency asked the AdvisoryBoard on the Buil the National Research Council to study the matter. The committee appoi I the study concentratedon two issues: (1) the potential hazard of tr~ transported to the surrounding environmentfrom the structure, and (2) sequence of events that would affect the structure’sphysical integrit~ active hazards that would result from preachmentof the dome. ~The comn concludes that the containment structure uresents no health hazard to t now or In the future. The committee went on to recommend periodic ins~ dome. Runit Island, on which the dome is situz~ed,was found to be un~ toxic plutonium particles in the soil and was placed off-limits foreve] the committee examined the possible radiation hazard on nearby Enjebi I nuclear weapons, nuclear testing program,-radiologicalcleanup, radioat uranics, plutonium,nuclear hazards, nuclear waste containment structu] DNA, Enewetak Atoll, Marshall I:lands, Cactus Crater, Runit Island, En: :This report has been approved for its distribution is unlimited ed ED condocz tion of tbe

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Function of the Dome Radionuclides in the Dome Transuranics in the SurroundingEnvironment Comparisons with Other Locations Transuranics in Marine Foods Eazards Associated with Leaching from the Cent Hazards Associated with Breachhg of the Conta

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CHI= ON EVALUATION OF BNEWETM mIoAcTIVITY a ROBERT W. MORSE, Woods F.oleoceanographic Institution, Node JOHN P. GNAKDINGER, Soil Testing Services, me., N@hbrook, STEPHEN M. KIM, RMC Technical Services, Radiation Management COLIN A. MAWSON, Ottawa, Ontario, Canada WILLIAM F. MERRITT, Health Sciences Division, Chalk River Nu Lahoratories, Chalk River, Ontario, Canada ALFRED A. YEE, Alfred A. Yee and Aasooiates, Inc., Honolulu, JAMES R. SMITH, Principal Staff Officer DAVID STARK, Consultant CLARET H. HEIDER, Editorial Consultant DELPHINE D. GLAZE, Administrative Secretary BETTY LOU WELIS, Secretary

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ADVISORY BOARD ON THE BUILT ENVIRONMENT I WERNBR A. BAUM, College of Arts and Sciences, P1OCMS State m Je r.city, G. DAY D=, Small Homes--Building Research council, University of Illinois. JOHN C. HORNIZW, General Electric Company, Schenectady,New Yorh GEORGH S. JHNKINS, Consultation Networks Inc., Washington, D.C. OLIVHR H. JONES, Oliver Jones and Aasoc<ates,Manns Choice, STANISLAV V. KASL, Department of Epidemiologyand public Health Yale University, New Haven, Connecticut NcGREGOR, Coamunity Facilities Department, Internati-L 1 wgy Universityof North Carolina, Chapel Hill SHIRLEY P. WEISS, Department of City and Regional Planning, Tbe Cliversity of North Carolina, Chapel Hill

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LEE S. GARRETT, Arlington, Virginia MAXINE SAVITZ, Deputy As8i8tant Secretary for Conservation, Of Cite of Comervation and Solar ~ergy, Department of Energy, Washi igton, D.C. of Standarda, Washington, D.C. JOSXPE ii.ZEITEL, Kastern Solar Utilization Network, Portland, Oregon

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Betu-en 1948 and 1958 Enewetak Atoll in the Marshall Islands for u.S. nuclear weapons testing and 43 devices were exploded here. In 1972 the federal government announced that it would rehabil tate the atoll and return it to the gwernment af the Trust Territory o the Pacific Islands and, subsequently to the Enewetak people, who had been moved to Ujelag in 1947, 125 miles southwest of Enewetak. The Enewetak rehabilitationeffort involvedmany departmen s of the federal gwernmant with the Defense Nuclear Agency (DNA) being charged with the major radiologicalcleanup responsibility. In the pr Ss of this cleanup, radiologicallycontaminated soil and debris fr many of the islands in the atoll were collected and transported to R t Island on the eastern side of the atoll. The contaminatedmaterial contained in a soil-cement matrix in (%ctus Crater* which had een formed by one of the nuclear detonations. fiis material was rrounded by a concrete key-wall and cwered by a concrete cap. I In crder to prwide the people of Enewetak and the Mershaaese government with an objective assessment of the safety of this ment structure, the DNA r,eguestedthe National Acad;my of Sci ces, through the M3visory Board on the Built Environment (ABBE) o the National Research Council, to ‘assess the effectivenessof th Cactus Crater structure in preventing harmful auu..untsof radioactive from becoming available for internal or extern-.L human exposure”; e DNA added later that this assessment should b~ “set against an un rstanding of the expected living patterns r E the people of En tak in terms of their degree of contfi.-::with Rur.it Island and their The committee appointed to cenclue%the study concentrated rimarily on two issues: (1) the potentia.. ported to the surrounding enviro~wrmt from the structuze in i present configuration, and (2) possible sequences of events that COU1 affect the structure’s physical integrity and an estimation of radio~tive hazards that might result from the dome’s brmachment. Two su idiary issues also concerned the committee and are commented on in t namely, possible hazards associated with the quarantined isla of lFormerly the Building Research Advisory Board (BRAB).

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remit where the domb in located, and possible hazards fr~ fisl products that maY arise if the northern island of Enjebi is ref Although this committee’s charge was not expressly directed lxx hazards associated with the resetb.lementof rnjebi, it must be emphasized that the risks from the conmnaption of food grown il northern islands are high compared with any conceivable risk a) from rupture of the dome. The reader of thin report will discover that thetc-ttee heavily on information furnished by government agencies and th Insofar as possible it attmspted to assess the qual these data and, in one Important instance (the drilling progr described in the report), supervised the a~isitia of new i about the quality of the dew’s construction and the concentr radioactivity contained within it. In its interpretationof hazards associated with the dome the committee depended heavilf on data acquired by groups at the Lawrence Livermore L8hOratCrieS led DY v. ~. sampling and analysis procedures used by these groups. In ad{ition# all the work on the Bnewetak cpwation done by these groups b s been subjected to critical review by a select panel of experts fro! oiher government laboratories and from universities; much of the WC:k d.SO is published in scientific journals and, thus. has been subj=!ted to peer review there. The -ttee therefore is satisfied that the information it has received concerning environmental sampling, analysis, and dose assessment is of high quality. The Committee on Evaluation of Bnewetak Radioactivity Con”a inment wishes to acknowledge the cooperation of the manY individualswho Provided extensive information and assistance. The committee la particularly grateful to Thomas Jeffers, Director for bgistics and Ray, Deputy for Pacific Operation, Nev’?daCW.erationsOffice, Department Command, DNA* Kirtland Air Porte Base, XeLt:=zicor William Wb ison, California; victor Noshkin, Marine Sciences, mvironmental s ierices David Stark, Concrete Materials Resear&h Department, Portlan Cement Amwciation, Skokie, Illinois.

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its assessment of the effectivenessof Crater structure in preventing harmful amounts of radioactivity om becoming available for internal or external human exposure, the Committee on ~aluation of Enewetak RadioactivityContainmentor ized a drilling program to obtain cores through the entire depth of finished containment structure, visited Enewetak Atoll to ~~in the structure and observe tne drilling operation reviewed all rele t data and reports connected with the cleanup program, and intervi ad key individuals associated with the program, including those re nrisiblefor radiation measurements and their interpretation. Duri its deliberations, the committee focused on such issues as the natur of the radioactive materials contained within the structure, the PO ible changes that might occur to the structure as time passes, the wa in which radioactive material now contained in the structure concei lY might be transported elsewhere, and the radioactive risks to whi the people of Enewetak would be exposed in the most extreme of these 1.1 The Containment Structure The committee believes that the Cactus Crater containment strlcture and its contents present no credible health hazard to the people )f Enewetek, either now or in the future. The fuaction of the containment structure, as the committee p kr-- ceives it~ is to prevent hazardous human exposure to the radioact.ve material buried within it, and the committee beiieves it in bighl? unlikely that any sequence of events would prevent the structure :rom performing this function. Any flushing or spilling of the Contea:s of the structure into the lagoon or ocean that mlghh occur as a resu.t of cracking, settlement or ‘tom damage will not create an meccept tile radioactive hazard. Indead. even if the entire radioactiveconteits of the containment structure were to find its wq into the lagoon, no unacceptable hazard would result. Although no significant radioactivehazard would bticreated i ! the comtahment structure were to fail in any way, it is prudent to m bintain the physical integrity of the strecture in order that it may continue to prevent direct human access to the radioactive materi.1 it contains. Thus, inspection of the dome should take place periodi:ail.y

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and after severe storms. Cracking or settling of the panels shod not b? of concern, but breaches in the riprap should be repaired to pr ide protection against wave action during storms. The committee was asked that its assesmnt of the Cactus Crat structure be ‘set against an understanding of the expected living patterns of tbe people of Enewetak in terms of their degree of con with Runit Island and their axposure otherwise to residual radioac ity on the atoll.- In this zegard the committee makes t= ccxment There is a hazard of uncertain ma~+tude on Runit Island bacau e of the possible presence of plutonium not located and removed duri 9 the cleanup (a situation unique to Runit), andv for this reason, it has been made off-limits, a status thz &ttee does not dispute. It is likely, however, that the people of lMmtetsk and others beli Runit to be off-limits becsuse of hazards amsociatadwith the containment structure. The ccwnittae therefore emphasizes that i conclusion regarding the safety of the structure shculd not be in rpreted to mean that Runit is thought to be harmleas. It may well that am important future function of the containment structure wi be to serve as a reminder to everyone that the island is to be avoid in view of the Wssible presence of plutonium there. It is likely that the Dri-Eniebi sooner or later will resettl their home isl&ds in the ncrthekn part of the atoll. Radiation exposures associated with such a move far exceed any exposures tb be associated with the d-e or with the radioactivityremaining i lag-. Indeed, for people who might live on Emjebi in the near future, radiation exposures due to strontiutu-+~oz cesium-137 in locally grown foods may become excessive in relation to current u standards for a ge%eral population, especially if food is not imp from other islands of the atoll or from outside.

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2.1 Nature of the Is?.ands The Marshall Islands, which comprise the eastern part of Marshalla consist of 29 coral atolls and 5 coral islands havi land arua of only 70 square miles (Figure 1). Each atol~ con many separate islands connected by coral reefs that usually f enclosure around a central lagoon. “Tlw temperature in the Marshalls averages about 80°F with seasonal variation. The northern islands receive about 60 in rain annually and the sou’fiernislands, about three times the but moisture rapidly drains out of the soil end the islands a tively arid. The amount of rainfall also varies considerably to year in the northern islands and droughts are ccnamon. m consist of coconut, pandanusc arrowroot, and bread fruit. Fz conditions are not infrequent because of drought even though and lagoons provide a stable source of marine food (Tobin 194 Prior to World War II, the economy of the Narshalls was t subsistence crops and fishing, supplemented by the export of dried meat of the coconut). This continues to be the case tc most of the islands; however, govwz::mentactivities at Majurc the missile range on Kwajalein M* mw major sources of eaplc hence, of income for the people in the MarshaUs. In 1977, the total population of the islands was estimstt 25,000. Of these, 8,000 were at Najuro and 5,000 on Ebye Zsl Kwajalein. A portion of the money earned “>yMarshallese eapl these two centers filters back to the subsistence-basedMar sumably, the economy at Enewetak after resettlementwill be t subsistence crops and fishing, incomes from relatives employe Majuro and Kwajalein, export crops (initiallynonexistent), ? su?port programs insofar as they continue to exist after inde Enewetak …