An analysis of plutonium immobilization versus the "spent fuel" standard

Safe Pu management is an important and urgent task with profound environmental, national, and international security implications. Presidential Policy Directive 13 and analyses by scientific, technical, and international policy organizations brought about a focused effort within the Department of Energy (DOE) to identify and implement long-term disposition paths for surplus Pu. The principal goal is to render surplus Pu as inaccessible and unattractive for reuse in nuclear weapons as Pu in spent reactor fuel. In the Programmatic Environmental Impact Statement and Record of Decision for the Storage and Disposition of Weapons- Usable Fissile Materials (1997), DOE announced pursuit of two disposition technologies: (1) irradiation of Pu as MOX fuel in existing reactors and (2) immobilization of Pu into solid forms containing fission products as a radiation barrier. DOE chose an immobilization approach that includes �use of the can-in-canister option.. . for a portion of the surplus, non-pit Pu material.� In the can-in-canister approach, cans of glass or ceramic forms containing Pu are encapsulated within canisters of HLW glass. In support of the selection process, a technical evaluation of retrievability and recoverability of Pu from glass and ceramic forms by a host nation and by rogue nations or subnational groups was completed. The evaluation involved determining processes and flowsheets for Pu recovery, comparing these processes against criteria and metrics established by the Fissile Materials Disposition Program and then comparing the recovery processes against each other and against SNF processes

Nanostructured Polymer Lithography for Photovoltaic Applications

The self-assembly of diblock copolymers into ordered domains holds great potential to furthering the efficiency of photovoltaic devices. Solutions containing polystyrene-block-poly(ethylene oxide) (PS-b-PEO) and poly(methyl methacrylate) (PMMA) were applied to silicon wafers from toluene solutions. Hexagonally ordered domains, with pore sizes ranging from 10-30 nm, were obtained by annealing films in solvent vapor, with the best results produced from a humidified benzene environment. Exposing the films to UV light cross-linked the polystyrene matrix and degraded the PMMA. Removal of the PMMA and PEO produced an ordered polystyrene template, which can be used for nanolithography for the deposition of quantum dots onto the wafers. Details of the film preparation, annealing times and conditions, and characterization will be presented

Effects of harvest season on carcass characteristics of lambs in the Intermountain West

Objective: The objectives of this study were to survey characteristics including hot carcass weight (HCW), 12th rib fat thickness (RFT), body-wall thickness (BWT), longissimus muscle area (LMA), USDA yield grade (USDA YG), percentage closely trimmed retail cuts (RC), and calculated yield grade (Calc YG) of lamb carcasses in the Intermountain West to determine the effects of season of slaughter and interrelationships among carcass characteristics. Materials and Methods: Lamb carcass characteristics were evaluated in 2 commercial Intermountain West processing plants over one year (n = 10,027). Carcasses were evaluated by season: spring (December–April, n = 2,322) and summer (May–August, n = 7,705). Results and Discussion: Carcasses of lambs slaughtered in the spring had 3.4 kg heavier HCW (P = 0.04) than those slaughtered in the summer. Subcutaneous fat (RFT; P = 0.06) and Calc YG (P = 0.09) tended to be greater in the spring than summer. Correlation coefficients and models of fit with a linear covariate of HCW indicated negative relationship between HCW and RC and positive relationship with all other carcass traits (P \u3c 0.001). Overall, graded lamb carcasses exceeded commercial processing plant preferred HCW (38.6 kg) by 5% (mean = 40.5 kg) and industry acceptable RFT (6 mm) by 25% (mean = 8.03 mm). Furthermore, 70% of lamb carcasses exceed 6 mm RFT. Implications and Applications: Season of slaughter contributed to differences in HCW and USDA YG but no other carcass characteristics. Still, carcass data surveyed from the largest lamb-producing region of the United States suggests that the degree of fatness exceeds industry preferences. Although abattoirs mitigate adverse effects of excessive fat through trimming and diverse market outlets, industry-wide efforts that agree on acceptable standards of trimness are needed. Transparent dialog across industry segments should be prioritized in addition to consistent integration of value-based pricing to reduce the proportion of excessively finished lambs

Global Ethics and Nanotechnology: A Comparison of the Nanoethics Environments of the EU and China

The following article offers a brief overview of current nanotechnology policy, regulation and ethics in Europe and The People’s Republic of China with the intent of noting (dis)similarities in approach, before focusing on the involvement of the public in science and technology policy (i.e. participatory Technology Assessment). The conclusions of this article are, that (a) in terms of nanosafety as expressed through policy and regulation, China PR and the EU have similar approaches towards, and concerns about, nanotoxicity—the official debate on benefits and risks is not markedly different in the two regions; (b) that there is a similar economic drive behind both regions’ approach to nanodevelopment, the difference being the degree of public concern admitted; and (c) participation in decision-making is fundamentally different in the two regions. Thus in China PR, the focus is on the responsibility of the scientist; in the EU, it is about government accountability to the public. The formulation of a Code of Conduct for scientists in both regions (China PR’s predicted for 2012) reveals both similarity and difference in approach to nanotechnology development. This may change, since individual responsibility alone cannot guide S&T development, and as public participation is increasingly seen globally as integral to governmental decision-making

Highly efficient separation of actinides from lanthanides by a phenanthroline-derived bis-triazine ligand

The synthesis, lanthanide complexation, and solvent ex- traction of actinide(III) and lanthanide(III) radiotracers from nitric acid solutions by a phenanthroline-derived quadridentate bis-triazine ligand are described. The ligand separates Am(III) and Cm(III) from the lanthanides with remarkably high efficiency, high selectivity, and fast extraction kinetics compared to its 2,2'-bipyridine counterpart. Structures of the 1:2 bis-complexes of the ligand with Eu(III) and Yb(III) were elucidated by X-ray crystallography and force field calculations, respec-tively. The Eu(III) bis-complex is the first 1:2 bis-complex of a quadridentate bis-triazine ligand to be characterized by crystallography. The faster rates of extraction were verified by kinetics measurements using the rotating membrane cell technique in several diluents. The improved kinetics of metal ion extraction are related to the higher surface activity of the ligand at the phase interface. The improvement in the ligand's properties on replacing the bipyridine unit with a phenanthroline unit far exceeds what was anticipated based on ligand design alone

Measurement of the WW Boson Mass

A measurement of the mass of the $W$ boson is presented based on a sample of 5982 $W \rightarrow e \nu$ decays observed in $p\overline{p}$ collisions at $\sqrt{s}$ = 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a fit to the transverse mass spectrum, combined with measurements of the $Z$ boson mass, the $W$ boson mass is measured to be $M_W = 80.350 \pm 0.140 (stat.) \pm 0.165 (syst.) \pm 0.160 (scale) GeV/c^2$.Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures (submitted to PRL