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The article discusses the factors that led to the weakening of U.S. export controls on bomb-grade uranium. The Energy Policy Act of 2005 which includes an amendment that eased off restrictions on the export of highly enriched uranium was forced into law by foreign producers of medical isotopes, their U.S.-based lobbyists, sectors of the U.S. medical community and the compliant lawmakers. The primary agitator for this was Canada's Nordion, the world's largest producer of medical isotopes and the main supplier to the U.S.

The article presents a timeline of the history of the Fast Flux Test Facility (FFTF) of the U.S. Construction of the plutonium breeder reactor program started in December 1970. Congress ends funding for the Clinch River reactor in November 1983. A Tri-Party Agreement was signed by the Energy Department with the Environmental Protection Agency and the Washington State Ecology Department to clean up the Hanford site. During operations, the FFTF produced isotopes for medical and industrial purposes, tritium for the U.S. fusion research program and conducted research for Japan's breeder program.

An understanding of the factors influencing the isotopic composition of body water is important to determine the isotopic composition of tissues that are used to reconstruct movement patterns of humans. The δ2H and δ18O values of body water (δ2Hbw and δ18Obw) are related to the δ2H and δ18O values of drinking water (δ2Hdw and δ18Odw), but clearly distinct because of other factors including the composition of food. Here, we develop a mechanistic geographical information system (GIS) model to produce spatial projections of δ2Hbw and δ18Obw values for the USA. We investigate the influence of gender, food, and drinking water on the predicted values by comparing them with the published values. The strongest influence on the predicted values was related to the source of δ2Hdw and δ18Odw values. We combine the model with equations that describe the rate of turnover to produce estimates for the time required for a non-resident to reach an isotopic equilibrium with a resident population. [ABSTRACT FROM AUTHOR]

The Radiochemical Engineering Development Center (REDC) at the Oak Ridge National Laboratory is the production, storage, and distribution center for the heavy-element research program of the U.S. Department of Energy. The REDC and the neighboring High Flux Isotope Reactor (HFIR) were built to produce quantities of transuranium elements for use in national and international research programs and since 1966 has been the main center of production for transcurium elements in the United States. In 2009, REDC successfully completed Campaign 74, its latest Bk-249/Cf-252 production campaign. The Transuranium Analytical Laboratory (TAL), located within REDC, provides the needed chemical and radiochemical analyses on a wide variety of nuclear matrixes in support of these production campaigns of transcurium isotopes. Titrations, dissolutions, separations, and dilutions of high activity samples are completed in hot-cells and glove-boxes in preparation for analytical radiochemistry determinations completed at the TAL in support of the REDC's mission. Within Campaign 74, the Transuranium Analytical Laboratory implemented a quick and reliable radiochemical method for the determination of Bk-249 that was used throughout the purification process at key hold points to ensure the delivery of a final purified product. [ABSTRACT FROM AUTHOR]

Argonne National Laboratory of the United States and Kharkov Institute of Physics and Technology of Ukraine have been collaborating on the conceptual design development of an electron accelerator-driven subcritical facility. The facility will be utilized for performing basic and applied nuclear research, producing medical isotopes, and training young nuclear specialists. This paper presents the design and analyses of the biological shield performed for the top section of the facility. The neutron source driving the subcritical assembly is generated from the interaction of a 100-kW electron beam with a natural uranium target. The electron energy is in the range of 100 to 200 MeV, and it has a uniform spatial distribution. The shield design and the associated analyses are presented including different parametric studies. In the analyses, a significant effort was dedicated to the accurate prediction of the radiation dose outside the shield boundary as a function of the shield thickness without geometrical approximations or material homogenization. The MCNPX Monte Carlo code was utilized for the transport calculation of electrons, photons, and neutrons. Weight window variance-reduction techniques were introduced, and the dose equivalent outside the shield can be calculated with reasonably good statistics. [ABSTRACT FROM AUTHOR]

Neutrons have always been produced by spallation reactions with the high energy beams hitting various targets at CERN, but it was not before 2000 that neutrons were produced on purpose for experiments related to problems in nuclear astrophysics and technology. Initiated by Carlo Rubbia and his colleagues [1] and supported as a European project [2] the construction of n_TOF facility started in 2000. In parallel, the n_TOF Collaboration was established with about 120 participants from more than 30 institutes, mostly from the EU, but also from the United States and Russia, to build the experimental equipment for neutron cross-section measurements and to prepare the first measurement campaign from 2002 to 2004. The main goal of the n_TOF project was “to produce, evaluate and disseminate cost-effectively neutron induced reaction cross sections for isotopes relevant to the Stellar Nucleosynthesis, to Nuclear Physics and to the concept for an Accelerator Driven System. In total, 40 fission and capture cross-sections in the mass range between 24Mg and 245Cm have been successfully measured during the first campaign. Presently, the n_TOF Collaboration is preparing for the second campaign 2009-2012 after the facility was refurbished and after a new spallation target has been installed. [ABSTRACT FROM AUTHOR]

Modern Nuclear Physics requires access to higher yields of rare isotopes, that relies on further development of the In-flight and Isotope Separation On-Line (ISOL) production methods. The limits of the In-Flight method will be applied via the next generation facilities FAIR in Germany, RIKEN in Japan, and RIBF in the United States. The ISOL method will be explored at facilities including ISAC-TRIUMF in Canada, SPIRAL-2 in France, SPES in Italy, ISOLDE at CERN, and eventually at the very ambitious multi-MW EURISOL facility [1]. ISOL and in-flight facilities are complementary entities. While in-flight facilities excel in the production of very short lived radioisotopes independently of their chemical nature, ISOL facilities provide high Radioisotope Ion Beam (RIB) intensities and excellent beam quality for 70 elements. Both production schemes are opening vast and rich fields of nuclear physics research. [ABSTRACT FROM AUTHOR]

Several techniques are available to forensic researchers to age-date and fingerprint gasoline releases to the environment. These techniques include the use of isotopes, chemical ratios, and groundwater flow rates, among many others. A case study is presented which describes the use of these methods congruently to assess the time frame of a gasoline release and assess whether or not more than one release had occurred. The principles discussed herein can be used to estimate the age(s) of subsurface gasoline releases in the 50 United States and the U.S. Territories in the Caribbean. [ABSTRACT FROM AUTHOR]

The recent controversy over the use of MTBE within gasoline to boost oxygen content and decrease carbon monoxide emissions to the atmosphere has led to a proposed phase-out of this compound by 2002. This paper is a preliminary investigation into the use of gas chromatography isotope-ratio mass spectrometry (GCIRMS) to determine both carbon and hydrogen isotopic compositions of MTBE as a means of differentiating sources of MTBE. Three pure MTBE samples were purchased from chemical distributors. Little variation of the δ 13 C values were observed although the samples had isotopically distinct δ-D values. Four different methods of obtaining carbon isotope ratios of neat MTBE, MTBE in gasoline, and MTBE in water are described, and the precision and accuracy of each is discussed. The carbon isotopic compositions of MTBE within 10 gasoline samples from three different areas of the United States show a wide range of carbon isotope compositions. This novel method of MTBE analysis could be valuable in forensic investigations. [ABSTRACT FROM AUTHOR]

Introduces a series of articles on several issues concerning isotopic practitioners and ecologists, highlighted at the 3rd International Conference on Applications of Stable Isotope Techniques to Ecological Studies in Flagstaff, Arizona.

Editorial. Comments on the emergence of forensic techniques to examine different sources of perchlorate in the environment. Examples of perchlorate-impacted facilities in the U.S.; Use of stable isotope analysis; Toxicological implications of perchlorate exposure; Observations by environmental scientists.