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SUGGESTIONS FOR 1F:CLUSIONIN THE ENVIRONMENTAL IllPACTSTATEbiENTFOR THE ENINETOK ATOLL CLEANUP The testing of nuclear detonation requires testing grounds that, among other factors, are remote from populated areas. Previously, two tests'had been conducted at Bikini Atoll in June and July 1946 under Operation Crossroads and, earlier, near Alamogordo, New Mexico '- on 16 July 1945 as Operation Trinity. However, for a continuing program of testing, Bikini suffered deficiencies in that the land winds to permit construction of a major airstrip.' This led to the selection of Eniwetok Atoll for testing nuclear detonations, a selection administratively approved by President Truman on 2 December The selection of Eniwetok Atoll was based on a study of possible ocean sites made by Captain J. S. Russell, USN, Deputy Director of the Division of,Military Applications, and by Dr. Darol K. Froman of the LOS Alamos Scientific Laboratory. In regard to possible fallout, Eniwetok Atoll was well located by having hundreds of miles of open sea lying from the Atoll in the westwardly direction of the prevailing winds. Washington Press, Seattle, 1926)
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. . The first of the groups assembled to conduct nuclear weapons tests on Eniwetok Atoll organizationally came into being on 18 October 1947. Called Joint Task Force Seven, the group was composed of personnel from many !I.S. governmental Agencies.* Not having significant gfiruid facilities on Eni\;retokAtoll, the Task Force Seven operated from their,many surface ships. Three nuclear detonations were made in this Operation Sandstone, which occurred_,duringApril and Inlayin 1948.3 The detonations were on 200 ft. towers; the-first on Engebi, the second on Biijiri, and the third on Runit. The largest yield was the second .with a yield of 49 kilotons.4s5 This kiloton terminology means that . the explosive energy of the nuclear 6f high explosive. (A table at the of these and the following tests at location, height of burst, position detonation equals 49 thousand tons end of this section gives for each (airdrop, barge, ground surface, or undereater) of nuclear explosive, cloud height, and yield.) In preparation for the next series of nuclear tests, the Atomic Energy Commission in mid-1949 decided to facilitate further testing by refurbishing Eniwetok with improving ground-based structures and by providing more adequate technical facilities? based on a survey submitted by Holmes and Narver, 1949. The Commission approved the recommendation April 1949, and the contract was signed in June.6 This work was Inc., on 7 January for construction in 4. Samuel Glasstone, The Effects of FluclearI:'eanons Department of the_-' "Tabulation of Data on Announced b!uclearDetonations by All house for Federal Scientific & Tech info, Springfield, Va.
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On 31 January 1950, President Truman made public the decision to develop a thermonuclear bomb, a decision which, of course, was to have great impact on Eniwetok Atoll. Test of weapons with such large increases in yield and fallout radiation are not suitable for tests on the continental United States, but are better suited'for the remoteness of the Pacific Proving Ground. To facilitate tests of devices that at first were limited to the 20-kiloton nominal yield of the Hiroshima weapon, the Nevada Proving Ground, near Las Vegas, Nevada, was additionally established in the autumn of 1950. The.first tests there were in a 1951 series starting on 27 January. The Eniwetok Atoll test series also planned for 1951 was designated as Operation Greenhouse and included, among other tests, activities related to thermonuclear research, but not yet involving a full thermonuclear explo- . sion. Between.7 April and 24 Flay 1951, four tests from.towers were conducted A full thermonuclear explosion was achieved the following year in the 1952 test series Operation Ivy at Eniwetok Atoll,u This involved only two tests, but ones of considerable significance and consequences. The first was Test Ffike, the first thermonuclear detonation , which was a ground level explosion amounting to 10.4 megatons (equivalent of 10.4 million tons of high explosive) on 1 November 1952 on a small island, Elugelab (Eluklapin in Marshallese, and Flora by the U.S. code name), at the north end of the Atoll. Being a surface explosion and having this large yield, Test.Plikeactually removed this small island from the Atoll chain. A large reinforced concrete building built on the nearby large island of Engebi to test effects of pressure was partly damaged. The second test of Operation Greenhoyse was a "high yield" explosion, Test King, from an air drop over Runit Island.
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. . Associated with the greater yield of Mike, which was dozens of times greater than previously experienced, was a corresponding increase in the fallout radiation. Contrary to expectations, the winds prevailing at the time were from the south or southeast,Tand so most of the radioactive debris fell on the open seas to the north and northwest. Nevertheless, fallout did occur on the northern islands of the Atoll. Since these islands continued to be uninhabited, no harm resulted to humans from this local fallout. . U.S. tests were conducted only at the Nevada Proving Grounds in 1953, thereupon starting the pattern of tests entirely at the Nevada Proving Grounds or the Pacific Proving Grounds,each on alternate years. The next series of tests in the Pacific was in 1954 under the name Operation Castle. It involved a task force, which retained the number Task Force Seven of the 1947 force. m not been used for nucledr tests since‘1946. The 15;megaton thermonuclear tests Bravo in this series was conducted on the surface in Bikini Atoll on 1 March 1954%= The radioactivity of this Bravo event was particularly troublesome by unexpectedly being carried to the east, rather than to the north as had been fore-. seen. Harmful amounts of radioactivity fell out on the inhabitedatolls of ROngelaF Ailinginae, and Rongerik and on the Japanese fishing ship Fukuryu Plaru. These events resulted sharply renewed interest in radiological consequences, with principal focus on the Bikini series of tests. The Atomic Bomb Effect Research Commission. which had been established after the atomic bombing of Japan, Shunkotsu Maru of the Japanese Fisheries Training Marshall Islaid area for surl*eypurposes; this was followed by a U.S. cruise on the Coast Guard Cutter Roger B. Taney under the name
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; Operation Castle.continued with other tests at Bikini Atoll, but . with an enlarged exclusion of the oceanic'areas of possible fallout. The only detonation of Operation Castle made in Eniwetok Atoll was the Nectar shot, detonated on 14 May 1954 on a barge in the lagoon over the By 1954 the large island of had become a barren, sandy island trees had long since disappeared. Engebi (Janet in the U.S. code name) from which the coconut palms and other This major island.of 291 acres had been subjected to World War II bombardment and, by 1954, to four series of nuclear. weapons tests. The nuclear explosions produced blast and irradiated the island by instantaneous radiation from nuclear detonations and by delayed radiation of fallout. Nevertheless, colonies of rats continued to thrive on this -even though casulties resulted from the tests. _~ The 1956 series of tests in the Pacific Proving Ground was. called Operation Redwing. These took place at both Bikini and Eniwetok Atolls, with eleven . at Eniwetok Atoll. Part of Bogan Island (Irene in the U.S. code name) was removed on 6 June 1956 by test Seminole, which was positioned on the land surface. This Seminole crater is on the east side of the remainder.of Bogan Island. The other surface test in Operation Redwing was test Lacrosse, irhich formed a*crater at the Northern tip of Runit Island (Yvonne is the U.S. code name) in the tide lands on the ocean side of the island. One Bikini test in Operation Redwing was an airplane drop of a thermonuclear bomb 4313: with a yield.of several megatons.
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Early in 1958 a 'moratorium against further testing of nuclear explosions. . was under consideration, partly in reaction to international concern about the world-wide fallout of radioactivity from nuclear tests by the several nuclear nations. Before the moratorium,however, an intensive series of tests called Operation Hardtack was'conducted. Operation Hardtack tooliplace in 1958 both . at Eniwetok Atoll as Phase I and at the Nevada Proving Grounds as Phase II, thereby breakin,0 the pattern of alternate testing years at the sites. Bep_en 5 May and 26 July 1958, &nt&two tests were conducted at Eniwetok under Operation Hardtack, Phase 1: This one intense period of testing thereby constitutedlover half of the 43 total tests conducted at the Atoll over the entire ten years of testing. Following Operation Hardtack, the joint . moratorium on testing by the U.S., and the U.S.S.R. started on 31 October . 1958. This marked the end~of all nuclear tests at Eniwetok. The intervening __ '15 years until the present time have allowed some natural restoration of . vegetation on affected islands and have provided the time for a tremendous decrease in the residual radioactivity resulting from the tests. %o islands were altered in this Operation Hardtack, Phase I. The , test Koa was a surface explosion on the small island Bogeirik (Bokaidrik in Marshallese and Helen by the U.S. code name). This test removed the island from the Atoll, The other was Test Cactus at the northwest tip of Runit Island (Yvonnc by the' U.S. codgname). This produced a crater nearby and to the Southvest of the La Crosse crater.
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Further tests did occur i@nthe Pacific, but they were in the vicinity of Johnston Island and Christmas Island;? so far to the east that there was no effect upon Eniwetok.Atoll. These tests followed the 1 September 1961 announcement by the U.S.S.R. of its intention to resume nuclear testing. The U.S.S.R.'tests occurred within days of this announcement. Bfanymonths later the United States started testing under a series called Operation Dominic, but, as just stated, not at was completed by the end of 1962 and which was signed in September 1963. except those conducted underground. Eniwetok Atoll. This test series was followed by the Limited Test Ban Treaty, This Treaty prohibited all nuclear‘tests Although underground tests have been conducted in the continental United States and at Amchitka in Alaska, none have been conducted at Eniwetok Atoll. . In these test series, a total of 43 nuclear detonations or attempts at nucleardetonatkolishave been nude at distribution of these 43 tests follows: Eniwstok %IGl:. The geographical 14 Information obtained from W. Robison, Lawrence Livermore Laboratory, * This island no longer exists. It was removed by test Plikc on 1 November 1952. undenqater craters from Nike and Koa overlap each other.
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The posi'tioning ok 35 of the nuclear explosives Positionins Number of Tests Of course, land surface tests were the mosf destructive to the physical'condition of the islands by producing still-existing craters or by removing an island entirely. Most barge tests were offshore on the lagoon side off the islands of Runit (Yvonne) and Enjebi (Janet). Being generally west of these islands, the tests produced radioactivity that the prevailing winds from the northeast 'generally carried away from the island and over the lagoon. In either the case of a successful nuclear detonation or the case of an unsuccessful nuclear detonation, a spread of radioactivity results in addition to physical damage to the land; vegetation, and animals. .In the case of a successful detonation, the following principal radioactive results are: 1. .fission products resulting from the fission of the uranium or plutonium used for the nuclear explosive, with (Their 27- and 28-year half lives, respectively, roughly correspond to human lifetimes, sothzydo not decay appreciably in an acceptable waiting period, nor do they decay sufficiently slowly to result in a low amount of radioactivity.
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cobalt-60, largely from activity induced in iron used for'towers, for decay more acceptable). various isotopes of plutonium produced from the neutrons by uranium in 'thenuclear detonation. The unconsumed plutonium and/or uranium used for the nuclear explosive but not having undergone fission. (When nuclear explosives misfire, the chemical-type high explosive used for assembling these nuclear components ultimately endsinstead in spreading ’ Tritium induced in water by neutrons and from thermonuclear reactions. (However, the mobility of the water in the ocean Even misfires or near misfires (low yield) of nuclear explosives result in a spread of radioactivity, as is seen by Item 4. In these misfire-cases, the residual uranium or plutonium is deposited over a much smaller area than for the case of the spread from a nuclear explosive (perhaps square yards of spread in the former case, but worldwide or at least square miles in latter). Some misfires are essentially intentional in that they are safety tests. A particular concern in a misfire is the spread of plutonium-239; the lower radio-. logicalhazard of uranium-235 causes very much less of a radiological concern when used as the nuclear material. This plutonium‘concern is complicated by its long 24-thousand year half life for decay, which is far too long for planning on decay to eliminate the hazard. l. Just such difficulties of plutonium contamination have occurred around Runit Island. For example, the test Scaevola in Operation Hardtack I was a
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one-point safety tCSt. Therefore, it was planned only to explode by hi'gh dxplosive but not by a nuclear explosion. Local spreads of plutonium esist near the middle of this long, narrow island.
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HEIGHT OF TYPE OF GEOGRAPHICAL COCRDIKATES ROKTH LAT * EAST LOSC YIELD REXARKS’ l
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euting” the rqwrt of the radiological mawa em l.md to difficultfar vbich ata9 be bard to carnet Ia the future if a document such aa this ts cfrculated. 5eiw uuclarrifted, it ham a potentially vide teadetrhip. War would be reluctant tr, l ee lnythiug dfrtributcd which d&at prejudice tha apewi9, the repart, aad the )mdgeaeat, and recandatfarv baaed on