The authors have measured the relaxation time of hot electrons in short pulse laser-solid interactions using a picosecond time-resolved x-ray spectrometer and a time-integrated electron spectrometer. Employing laser intensities of 10{sup 17}, 10{sup 18}, and 10{sup 19} W/cm{sup 2}, they find increased laser coupling to hot electrons as the laser intensity becomes relativistic and thermalization of hot electrons at timescales on the order of 10 ps at all laser intensities. They propose a simple model based on collisional coupling and plasma expansion to describe the rapid relaxation of hot electrons. The agreement between the resulting K{sub {alpha}} time-history from this model with the experiments is best at highest laser intensity and less satisfactory at the two lower laser intensities.

Development and poverty eradication are urgent andoverriding goals internationally. The World Summit on SustainableDevelopment made clear the need for increased access to affordable,reliable and cleaner energy and the international community agreed in theDelhi Declaration on Climate Change and Sustainable Development on theimportance of the development agenda in considering any climate changeapproach. To this end, six countries (Australia, China, India, Japan,Republic of Korea and the United States) have come together to form theAsia Pacific Partnership in accordance with their respective nationalcircumstances, to develop, deploy and transfer cleaner, more efficienttechnologies and to meet national pollution reduction, energy securityand climate change concerns consistent with the principles of the U.N.Framework Convention on Climate Change (UNFCCC). The APP builds on thefoundation of existing bilateral and multilateral initiativescomplements.APP has established eight public-private sector Task Forcescovering: (1) cleaner fossil energy; (2) renewable energy and distributedgeneration; (3) power generation and transmission; (4) steel; (5)aluminium; (6) cement; (7) coal mining; and (8) buildings and appliances.As a priority, each Task Force will formulate detailed action plansoutlining both immediate and medium-term specific actions, includingpossible "flagship" projects and relevant indicators of progress by 31August 2006. The partnership will help the partners build human andinstitutional capacity to strengthen cooperative efforts, and will seekopportunities …

Aluminum clad research reactor spent nuclear fuel (SNF) is currently being consolidated in wet storage basins (pools). Approximately 20 metric tons (heavy metal) of aluminum-based spent nuclear fuel (Al-SNF) is being consolidated for treatment, packaging, interim storage, and preparation for ultimate disposal in a geologic repository. The storage and disposal of Al-SNF are subject to requirements that provide for safety and acceptable radionuclide release. The options studied for interim storage of SNF include wet storage and dry storage. Two options have also been studied to develop the technical basis for the qualification and repository disposal of aluminum spent fuel. The two options studied include Direct Disposal and Melt-Dilute treatment. The implementation of these options present relative benefits and challenges. Both the Direct Disposal and the Melt-Dilute treatment options have been developed and their technical viability assessed. Adaptation of the melt-dilute technology for the treatment of spent fuel offers the benefits of converting the spent fuel into a proliferation resistant form and/or significantly reducing the volume of the spent fuel. A Mobile Melt-Dilute system concept has emerged to realize these benefits and a prototype system developed. The application of the melt-dilute technology for the treatment of legacy nuclear materials has been …

Two-dimensional magnetohydrodynamic simulations are performed using the ZEUS-2D code to investigate the dynamics of a collapsar that generates a GRB jet, taking account of realistic equation of state, neutrino cooling and heating processes, magnetic fields, and gravitational force from the central black hole and self gravity. It is found that neutrino heating processes are not so efficient to launch a jet in this study. It is also found that a jet is launched mainly by B{sub {phi}} fields that are amplified by the winding-up effect. However, since the ratio of total energy relative to the rest mass energy in the jet is not so high as several hundred, we conclude that the jets seen in this study are not be a GRB jet. This result suggests that general relativistic effects, which are not included in this study, will be important to generate a GRB jet. Also, the accretion disk with magnetic fields may still play an important role to launch a GRB jet, although a simulation for much longer physical time {approx} 10-100 s is required to confirm this effect. It is shown that considerable amount of {sup 56}Ni is synthesized in the accretion disk. Thus there will be a …

The ultrafast pulses from X-ray free-electron lasers will enable imaging of non-periodic objects at near-atomic resolution [1, Neutze]. These objects could include single molecules, protein complexes, or virus particles. The specimen would be completely destroyed by the pulse in a Coulomb explosion, but that destruction will only happen after the pulse. The scattering from the sample will give structural information about the undamaged object. There are many technical challenges that must be addressed before carrying out such experiments at an XFEL, which we are doing so with experiments at FLASH, the soft-X-ray FEL at DESY.

Chloride (Cl{sup -}) salt processing in strong acids is used to recycle plutonium (Pu) from pyrochemical residues. The Savannah River National Laboratory (SRNL) is studying the potential application of nitrogen dioxide (NO{sub 2}) gas to effectively convert dissolved pyrochemical salt solutions to chloride-free solutions and improve recovery operations. An NO{sub 2} sparge has been shown to effectively remove Cl{sup -} from solutions containing 6-8 M acid (H{sup +}) and up to 5 M Cl{sup -}. Chloride removal occurs as a result of the competition of at least two reactions, one which is acid-dependent. Below 4 M H+, NO2 reacts with Cl- to produce nitrosyl chloride (ClNO). Between 6 M and 8 M H{sup +}, the reaction of hydrochloric acid (HCl) with nitric acid (HNO{sub 3}), facilitated by the presence of NO{sub 2}, strongly affects the rate of Cl{sup -} removal. The effect of heating the acidic Cl{sup -} salt solution without pre-heating the NO{sub 2} gas has minimal effect on Cl{sup -} removal rates when the contact times between NO{sub 2} and the salt solution are on the order of seconds.

The formation and growth of sigma ({sigma}) phase in 2205 duplex stainless steel was observed and measured in real time using synchrotron radiation during isothermal heat treating at temperatures between 700 C and 850 C. Synchrotron experiments were performed on this material at the Advanced Photon Source (APS) while isothermally holding the samples for times of up to 10 hr. During the isothermal hold, sigma formed in quantities up to 22% as the ferrite transformed to a mixture of sigma and austenite phases. In addition, sigma formed at 850 C was heated to 1000 C to observe its dissolution. The amounts of sigma that formed, and the dissolution temperature of sigma were compared to the results predicted by Thermocalc, showing differences between the calculated and measured values. The synchrotron data was further modeled using a modified Johnson-Mehl-Avrami analysis to determine kinetic parameters for sigma formation. The initial JMA exponent, n, at low fractions of sigma was found to be approximately 7.0, however, towards the end of the transformation, n decreased to values of approximately 0.75. Because of the variable value of n, it was not possible to determine reliable values for the activation energy and pre-exponential terms for the JMA …