Papers by Keyword: Uranium Enrichment

Abstract: The growth condition,malonaldehyde (MDA),accumulation of uranium,glutathione (GSH),non-protein sulfhydryl (-SH) and phytochelatins (PCs) in Chinese cabbage subjected to different uranium stresses were investigated.The results showed that Chinese cabbage was sensitive to high dose of uranium concentrations.From the perspective of the adsorption quantity of uranium,the adsorption capacity of uranium in roots was obviously better than in stem and leaf. under 20 mg/L uranium stress,the MDA content significantly increased by 125% than the control group.And the analysis of the non-enzymes indicated that the SH,GSH,PCs played an important role in the process of eliminating uranium poison with the increase of the SH,GSH,PCs under increasing uranium concentrations.

Abstract: The Ordos basin Chang 7 hydrocarbon source rocks are the most important rock strata of premium oil source formed during the largest lake flood period of the terrestrial lacustrine. Our study found that the bottom of the rocks are rich in radioactive uranium. Element geochemical studies showed that the rocks are also rich in C, S, P, Cu, V, Mo and other pro-life elements but not rock-forming minerals-related lithophile elements Li, Zr, Sr, etc. Their uranium content has obvious positive correlation with phosphorus, sulfur, iron, organic carbon content, but not with major rock-forming elements. Petrography and scanning electron microscopy revealed the rocks are rich in pyrite, phosphate rock and striped organic matters. These features indicate that uranium enrichment and the presence of these minerals are closely related. The significantly positive correlation of the ratio of uranium to trace elements such as U/ (U+Ni) and U/Sc indicates that anoxic environment played an important role in uranium enrichment. Electron microprobe analysis found for the first time uranium ore and independent titanium-containing uranium minerals in phosphate rocks in the area. α radiation photography and sequential chemical extraction found that 50% of uranium present as independent uranium and its isomorphic minerals in the phosphate rocks, 20% is absorbed to pyrite and organic matter, and less than 10% is absorbed on clay minerals.

Abstract: Since the 1970's, global efforts have been going on to replace the high-enriched (>90% 235U), low-density UAlx research reactor fuel with high-density, low enriched (<20% 235U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U3Si2 dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U3Si2 (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development.