Background: Uranium hexafluoride (UF6) is nasty stuff. It is highly toxic, reacts violently when exposed to water or moist air, and is corrosive to most metals. It also incorporates a radioactive heavy metal (uranium), and it gives off two of the most biologically damaging types of radioactive emissions known: alpha radiation and neutrons. So who wants it? And why? Hex, as it is called in the industry, is one of the very few uranium compounds that can be turned into a gas at a relatively low temperature. And that gas is whats needed in uranium enrichment plants. At room temperature, however, it is a solid -- but look out if it happens to get wet! Uranium enrichment is a process whereby two almost identical types of uranium -- uranium-238 and uranium-235 -- are separated by using the fact that one of them (U-235) is ever-so-slightly lighter than the other one (U-238). It is a very slow, difficult, energy-intensive process, but it is necessary for most applications, whether civilian or military. The concentration of U-235 can only be increased (enriched) by separating out and discarding most of the U-238 (called depleted uranium). Some nuclear bombs require highly-enriched uranium (HEU), and most nuclear power reactors require low-enriched uranium (LEU). Neither of these products would be possible without hex. In order to enrich uranium, the uranium has to be in the form of a gas -- so you can diffuse it through membranes that act like very fine filters, or spin it in a centrifuge to make the heavier stuff (U-238) go to the outside wall and the lighter stuff (U-235) stay closer to the center. And thats why about 85 percent of all Canadas uranium production is exported in the form of uranium hexafluoride, manufactured at the Port Hope conversion facility on the shores of Lake Ontario. --------- There are very few nuclear materials that are nastier than uranium hexafluoride, but high-level radioactive liquid waste (HLLW) fits the bill. HLLW contains dozens of fiercely radioactive materials as well as uranium, in a highly corrosive acidic solution that remains liquid even at normal temperature and pressure. This material (HLLW) has never before been shipped over public roads, but within weeks, or months, Canada plans to start shipping dozens of convoys of this radioactive waste material in liquid form from Chalk River, Ontario, to Savannah River, South Carolina. There have been no public hearings on either side of the Canada/US border to consider the environmental implications of a loss-of-containment, or emergency measures to be taken in the event of such an accident, or alternatives such as solidifying the liquid before transporting it or foregoing the transport altogether. Nor has there been any justification given as to why this material must be shipped in liquid form, when solidification technology already exists and is in regular use. Gordon Edwards. P.S. It is not generally known that UF6 is a neutron emitter. Neutron radiation is very harmful to living things. It is not often encountered outside of a nuclear reactor. However it was discovered early in the 20th century that when an alpha emitter like uranium is in close contact with a very light element like fluorine, the alpha particles given off by uranium atoms will knock neutrons out of the nucleus of the lighter element. Neutrons are among the most penetrating types of atomic radiation and are particularly harmful to living cells. GE
Posted on: Wed, 19 Mar 2014 19:36:30 +0000
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