Testing Broken U(1) Symmetry in a Two-Component Atomic Bose-Einstein Condensate

We present a scheme for determining if the quantum state of a small trapped Bose-Einstein condensate is a state with well defined number of atoms, a Fock state, or a state with a broken U(1) gauge symmetry, a coherent state. The proposal is based on the observation of Ramsey fringes. The population difference observed in a Ramsey fringe experiment will exhibit collapse and revivals due to the mean-field interactions. The collapse and revival times depend on the relative strength of the mean-field interactions for the two components and the initial quantum state of the condensate.Comment: 20 Pages RevTex, 3 Figure

Treatment of plutonium process residues by molten salt oxidation

Molten Salt Oxidation (MSO) is a thermal process that can remove more than 99.999% of the organic matrix from combustible {sup 238}Pu material. Plutonium processing residues are injected into a molten salt bed with an excess of air. The salt (sodium carbonate) functions as a catalyst for the conversion of the organic material to carbon dioxide and water. Reactive species such as fluorine, chlorine, bromine, iodine, sulfur, phosphorous and arsenic in the organic waste react with the molten salt to form the corresponding neutralized salts, NaF, NaCl, NaBr, NaI, Na{sub 2}SO{sub 4}, Na{sub 3}PO{sub 4} and NaAsO{sub 2} or Na{sub 3}AsO4. Plutonium and other metals react with the molten salt and air to form metal salts or oxides. Saturated salt will be recycled and aqueous chemical separation will be used to recover the {sup 238}Pu. The Los Alamos National Laboratory system, which is currently in the conceptual design stage, will be scaled down from current systems for use inside a glovebox

Developing Large-Scale Research in Response to an Oil Spill Disaster: a Case Study

Research conducted in the wake of a disaster can provide information to help mitigate health consequences, support future recovery efforts, and improve resilience. However, a number of barriers have prevented time-sensitive research responses following previous disasters. Furthermore, large-scale disasters present their own special challenges due to the number of people exposed to disaster conditions, the number of groups engaged in disaster response, and the logistical challenges of rapidly planning and implementing a large study. In this case study, we illustrate the challenges in planning and conducting a large-scale post-disaster research study by drawing on our experience in establishing the Gulf Long-term Follow-up (GuLF) Study following the 2010 Deepwater Horizon disaster. We describe considerations in identifying at-risk populations and appropriate comparison groups, garnering support for the study from different stakeholders, obtaining timely scientific and ethics review, measuring and characterizing complex exposures, and addressing evolving community health concerns and unmet medical needs. We also describe the NIH Disaster Research Response (DR2) Program, which provides a suite of resources, including data collection tools, research protocols, institutional review board guidance, and training materials to enable the development and implementation of time-critical studies following disasters and public health emergencies. In describing our experiences related to the GuLF Study and the ongoing efforts through the NIH DR2 Program, we aim to help improve the timeliness, quality, and value of future disaster-related data collection and research studies

Application of molten salt oxidation for the minimization and recovery of plutonium-238 contaminated wastes

This paper presents the technical and economic feasibility of molten salt oxidation technology as a volume reduction and recovery process for {sup 238}Pu contaminated waste. Combustible low-level waste material contaminated with {sup 238}Pu residue is destroyed by oxidation in a 900 C molten salt reaction vessel. The combustible waste is destroyed creating carbon dioxide and steam and a small amount of ash and insoluble {sup 2328}Pu in the spent salt. The valuable {sup 238}Pu is recycled using aqueous recovery techniques. Experimental test results for this technology indicate a plutonium recovery efficiency of 99%. Molten salt oxidation stabilizes the waste converting it to a non-combustible waste. Thus installation and use of molten salt oxidation technology will substantially reduce the volume of {sup 238}Pu contaminated waste. Cost-effectiveness evaluations of molten salt oxidation indicate a significant cost savings when compared to the present plans to package, or re-package, certify and transport these wastes to the Waste Isolation Pilot Plant for permanent disposal. Clear and distinct cost advantages exist for MSO when the monetary value of the recovered {sup 238}Pu is considered

Nitrate Anion Exchange in Pu-238 Aqueous Scrap Recovery Operations

Strong base, nitrate anion exchange (IX) is crucial to the purification of {sup 238}Pu solution feedstocks with gross levels of impurities. This paper discusses the work involved in bench scale experiments to optimize the nitrate anion exchange process. In particular, results are presented of experiments conducted to (a) demonstrate that high levels of impurities can be separated from {sup 238}Pu solutions via nitrate anion exchange and, (b) work out chemical pretreatment methodology to adjust and maintain {sup 238}Pu in the IV oxidation state to optimize the Pu(IV)-hexanitrato anionic complex sorption to Reillex-HPQ resin. Additional experiments performed to determine the best chemical treatment methodology to enhance recovery of sorbed Pu from the resin, and VIS-NIR absorption studies to determine the steady state equilibrium of Pu(IV), Pu(III), and Pu(VI) in nitric acid are discussed

Child car restraints: Mandating type and seating row according to age with positive effect in regional city in Queensland, Australia

Road trauma is a leading cause of child injury worldwide. In highly motorised countries, injury as a passenger represents a major proportion of all child road deaths and hospitalisations. Australia is no exception, particularly since there are high levels of private motor vehicle travel to school in most Australian states. Recently the legislation governing the type of car restraints required for children aged under 7 years has changed in Australia, aligning requirements better with accepted best practice. However, it is unclear what effect these changes have had on children’s seating positions or the types of restraints used. A mixed methods evaluation of the impact of the new legislation on compliance was conducted at three times: baseline (Time 1); after announcement that changes were going to be implemented but before enforcement began (Time 2); and after enforcement commenced (Time 3). Measures of compliance were obtained using two methods: road-side observations of vehicles with child passengers; and parental self-report (intercept interviews conducted at Time 2 and Time 3 only). Results from the observations suggested an overall positive effect. Proportions of children occupying front seats decreased overall and use of dedicated child seats increased to almost 40% of the observed children by Time 3. However, almost a quarter of the children observed still occupied front seats. These results differed from those of the interview study where almost no children were reported as usually travelling in the front seat, and reported use of dedicated restraints with children was almost 90%, over twice that of the observations

Recycle of scrap plutonium-238 oxide fuel to support future radioisotope applications

The Nuclear Materials Technology (NMT) Division of Los Alamos National Laboratory has initiated a development program to recover and purify plutonium-238 oxide from impure feed sources in a glove box environment. A glove box line has been designed and a chemistry flowsheet developed to perform this recovery task at large scale. The initial demonstration effort focused on purification of {sup 238}PuO{sub 2} fuel by HNO{sub 3}/HF dissolution, followed by plutonium(III) oxalate precipitation and calcination to an oxide. Decontamination factors for most impurities of concern in the fuel were very good, producing {sup 238}PuO{sub 2} fuel significantly better in purity than specified by General Purpose Heat Source (GPHS) fuel powder specifications. The results are encouraging for recycle of relatively impure plutonium-238 oxide and scrap residue items into fuel for useful applications. A sufficient quantity of purified {sup 238}PuO{sub 2} fuel was recovered from the process to allow fabrication of a GPHS unit for testing. The high specific activity of plutonium-238 magnifies the consequences and concerns of radioactive waste generation. This work places an emphasis on development of waste minimization technologies to complement the aqueous processing operation. Results from experiments allowing more time for neutralized solutions of plutonium-238 to precipitate resulted in decontamination to about 1 millicurie/L. Combining ultrafiltration treatment with addition of a water-soluble polymer designed to coordinate Pu, allowed solutions to be decontaminated to about 1 microcurie/L. Efforts continue to develop a capability for efficient, safe, cost-effective, and environmentally acceptable methods to recover and purify {sup 238}PuO{sub 2} fuel

Burn and Bury Option for Plutonium.

Cubic-stabilized zirconia (ZrO2 doped with, for instance, MgO, CaO, Y2O3) is a fluorite-structure oxide that exhibits high chemical stability and durability. It is an actinide-host phase in which actinides have high solubility (over 10 wt.% for uranium and plutonium). In fact, cubic zirconia is isostructural with actinide oxides such as urania (UO2), plutonia (PuO2), and thoria (ThO2). Cubic zirconia exhibits good radiation damage resistance and so it is attractive as an actinide-bearing nuclear fuel-form and as an actinide-host waste form. We propose that cubic zirconia be used as a material to assist with the dispositioning of the global surplus plutonium inventory (both weapons- and reactor-derived plutonium). Plutonium can be incorporated in a cubic zirconia matrix and destroyed by burning in an existing light-water reactor and then buried in a geologic repository (perhaps without further processing); alternatively, the plutonium-bearing zirconia can be sent directly to a repository.JRC.E-Institute for Transuranium Elements (Karlsruhe