Archive for September, 2011

Rongelap Wanderings

September 22, 2011

Tales from the Nuclear Age

Copyright© 2011 by Charles Glassmire

 Sept. 21, 2011

 Rongelap Wanderings

           The wanderings of the Marshall Islands peoples begin in May of 1946. The United States is preparing for Operation Crossroads, a series of atomic bomb tests on Bikini Atoll, which might contaminate their home islands of Bikini and/or Rongelap, which are part of the Marshalls chain. Prior to the test the U.S. explains to the assembled tribe what is to happen with this new weapon which is for “the good of all mankind and to end all wars”. The natives reluctantly agree to leave their homes temporarily. Following the test, Rongelap survives Crossroads, and they are repatriated. The Bikinians are banished to Rongerik island.

          Years pass for the Rongerik natives, and back at home in their island paradise yet more tests loom on the horizon. The 1954 test labeled Bravo Shot detonates a new type of device named “Thermonuclear”. The wind changes direction the day before Bravo, and the test inadvertently contaminates the 82 Rongerik natives (estimates vary up to 95) living on the island.

          Unable to be rescued for some 51 hours after the detonation, these people live, eat, work and sleep in a snow-like fallout of strange (radioactive) white flakes which coats everything. By the second day they are showing symptoms of Acute Radiation Gastrointestinal Syndrome: nausea, vomiting, diarrhea, weeping skin “burns”, swelling of neck, arms and legs, and somewhat later, hair loss. At this time they are evacuated by the U.S. Navy and taken to Kwajalein Island for medical treatment.

          Miraculously, after several weeks, the skin wounds heal (ironically radiation has a somewhat cauterizing effect on local skin areas) and no deaths occur. Slowly the population seems to recover, but the long term effects are unknown. Preliminary estimates seem to indicate they have received much higher doses (especially to some internal organs) than even the Japanese survivors of Hiroshima and Nagasaki – an estimated 100-175 rads on adult age average. (Note: 450 rads short-term whole body exposure is sufficient to kill 50% of the exposed adult population).

          In 1954 there is no medical experience at these high dose levels. But as their homes are too highly contaminated to return, they have become people without a country. As wards of the U.S. government they are relocated to Ejit Island, Majuro to await their fate.

          Within a few days in early March, upon realizing that the human doses were unusually high on rongelap, in addition to their medical care, the AEC and Joint Task Force initiates a study of the medical effects on the population, in order to increase knowledge of biological effects and treatments at these higher dosages. The effort is called “Project 4.1” and is classified SECRET RESTRICTED, as are most weapons effects studies. The main project terminates after 2.5 months, but then the AEC decides that semi-annual and yearly follow-up exposure studies would be uniquely valuable.     Organizations in the project are Oak Ridge National Laboratory, the Naval Medical Research Institute, Naval Radiological Defense Laboratory, Naval Air Station Kwajalein, Los Alamos National Laboratory, Univ. of Washington Applied Fisheries Laboratory and Hanford Atomic Power Operations. Ongoing results are subsequently published as a Project 4.1 final report* and in journals such as JAMA.

          But the long term effects are still awaiting the people of Rongelap, now residing on Ejit. Life is difficult there. There is limited food and water. One main staple crab species consumes its own shell after moulting, and thus increases the residual radioactivity when eaten. Some fish in the bay sicken the villagers with high fever and nausea and chills, but they are eaten anyway. Cesium 137 (137C) deposits in the ground and, behaving like Phosphorous chemically, is taken up by the cocoanut trees and concentrates radiation in the cocoanuts.

          Finally three years later, in 1957 the U.S. government declares Rongelap safe for repatriation. The report declares the area “clean and safe…” but contains a disclaimer “… in spite of slight lingering radiation”. The native population is delighted to be allowed to return to their homes, but they are warned to eat only canned foods (supplied by the U.S. government) and to avoid northern portions of the atoll. Meanwhile the United States continues to run nuclear tests in the Marshalls. By 1963 thyroid tumors begin to appear among those exposed to Bravo…

(to be continued …)

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*Cronkite et.al., Study of Response of Human Beings Accidentally Exposed to Significant Fallout Radiation, Operation CASTLE-Final Report Project 4.1, Report #WT-923 (October 1954). Also see WT-936, 937, 938, 939.

**Estimation of the Baseline Number of Cancers Among Marshallese and the Number of Cancers Attributable to Exposure to Fallout from Nuclear Weapons Testing Conducted in the Marshall Islands”, Nat’l. Cancer Ins., Dept. H&HS, Sept. 2004.

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What Went Wrong?

September 2, 2011

Tales from the Nuclear Age

Copyright© 2011 by Charles Glassmire

 Sept. 2, 2011

 What went Wrong?

           To the astonishment of the scientific community, the Bravo shot of the 1954 Operation Castle had gone very wrong. Expecting a detonation magnitude of 3 to 5 megatons from this early thermonuclear device, the actual shot had measured out at over 15 megatons. The generated debris cloud had become many times greater in size than calculated and, together with an unexpected wind shift before the shot, had spread fallout eastward into some of the populated Marshall Islands of Rongelap, Rongerik and others. Test buildings had been destroyed, measuring instruments vaporized, abandoned ships sent to the bottom of the Bikini lagoon, 28 U.S. service men on the Rongerik weather station had been exposed, a Japanese fishing boat had been contaminated (later resulting in a fisherman’s death), and several hundred Marshallese received doses of radiation much higher than permissible levels.

          Some 200 of these Rongelap natives had been moved south to escape the fallout for safe treatment to Kwajalein Island. They abandoned their fallout-contaminated homes and belongings, and now, being temporary wards of the U.S. government, were a population without a country.

          Why was the Bravo shot three times more powerful than expected? The answer lies in the assumptions made by the Los Alamos designers regarding an isotope of the element Lithium, called Lithium seven ( 7Li )

         First we must note that a thermonuclear weapon is really two weapons in one. An “ordinary” atomic bomb is first set off and the heat and X-rays from this bomb are used to set off the second thermonuclear weapon, causing the hydrogen to fuse and releasing copious energy.

          To put Hydrogen gas into a Hydrogen Bomb, the gas must first be condensed to cryogenic temperatures. The first H Bomb test (Ivy Mike) had successfully done this, but the equipment to keep the gas cold was enormous, heavy, and cumbersome. No way could this approach ever become a usable weapon.

          So on this second test (Castle Bravo), the Hydrogen was supplied as a solid chemical called Lithium Deuteride, using heavy Hydrogen (called “Deuterium”). It didn’t need to be kept cold, and Lithium was an especially nice choice to be in the bomb because it has a very low binding force holding its nucleus together. Thus its nucleus is likely to break apart and give up extra energy to the detonation.

         But there was a “gotcha”.

          About 7 percent of natural lithium is the lithium 6 isotope (6Li), and 92 percent is the Lithium 7 isotope (7Li). Lithium 6 is expensive to make, but is more desirable since it was considered to fission easily in the detonation. So the Lithium Deuteride for the test was enriched to 40% Li 6 at great expense. The designers assumed Li 7 didn’t enter into the reaction much at all.

          Big mistake.

          Unknown at the time, it turns out Li 7 also fissions when hit with a neutron, giving off an alpha particle, a tritium nucleus and another neutron! The tritium (which is very heavy Hydrogen) then fuses with the deuterium and hydrogen floating around, adding to the fusion power released in the explosion! In addition, the free neutron increased the neutron flux available. This additional neutron flux then increased the fissions in the atomic bomb part of the detonation, releasing more fission power to the detonation!

          So failing to account for the behavior of the Lithium 7 isotope added severely to the released power of the thermonuclear explosion and also increased the amount of fallout generated. The Hydrogen reaction doesn’t produce any fission products. The fission products come from the atomic bomb part of the device, when atoms split apart creating other lighter radioactive atoms. The presence of higher neutron flux makes more fissions and generates more radioactive fallout.

          Perhaps there is some lesson here in the stumbling progression of human endeavors, especially among those who dare to meddle with the fundamental forces of the universe.

          As to the migration of the innocent Rongelap population, their journey is ongoing and will be continued in the next installment…

 (to be continued …)