Nuclear Commons^™

W-Boson Production With Large Transverse Momentum At The Lhc, Nikolaos Kidonakis, Richard J. Gonsalves, Agustin Sabio Vera

Faculty Articles

We study W-boson production with large transverse momentum, Q_T, in pp collisions at the LHC. We calculate the complete NLO corrections and the soft-gluon NNLO corrections to the differential cross section. The NLO corrections are large but they do not reduce the scale dependence relative to LO, while the NNLO soft-gluon corrections, although small, significantly reduce the scale dependence and thus provide a more stable result.

Production Of Large Transverse Momentum W Bosons At The Tevatron, Nikolaos Kidonakis, Agustin Sabio Vera

Faculty Articles

We discuss the production of W bosons at large transverse momentum in p pbar collisions at the Tevatron Run I and II. W boson hadroproduction is a process of relevance in testing the Standard Model and in estimates of backgrounds to new physics. The next-to-leading order cross section in the region of large transverse momentum is dominated by threshold soft-gluon corrections which arise from incomplete cancellations near partonic threshold between graphs with real emission and virtual graphs due to the limited phase space available for real gluon emission. In this contribution it is shown how, by including next-to-next-to-leading-order (NNLO) soft-gluon …

Soft-Gluon Corrections In Hard-Scattering Processes Through Nnnlo, Nikolaos Kidonakis

Faculty Articles

I discuss soft-gluon corrections in hard-scattering processes and their resummation. I present master formulas for the expansion of the resummed cross section through NNNLO and discuss the significance of these corrections in a number of processes.

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix: Neutronic Evaluation Of Zro2-Mgo Inert Fuels, E. Fridman, A. Galperin, E. Shwageraus

Fuels Campaign (TRP)

Various fuel cycle concepts for plutonium incineration in existing PWR loaded with Inert Matrix Fuel (IMF), in which uranium is replaced by neutron-transparent inert matrix material, are currently under investigation at BGU. Some of the studied designs include ZrO₂-based IMF with annular fuel geometry and ZrO₂-MgO based IMF with the relative amount of MgO varied from 30v/o to 70v/o. These concepts are analyzed via detailed three-dimensional full core simulation of existing PWR including thermal-hydraulic feedback. The whole core simulations are carried out with the SILWER code. The SILWER code, which is a part of the ELCOS …

University Of Nevada, Las Vegas Transmutation Research Program Annual Report Academic Year 2005-2006, Anthony Hechanova, Rebecca Arbour

Transmutation Research Program Reports (TRP)

It is my pleasure to present the UNLV Transmutation Research Program’s fifth annual report that highlights the academic year 2005 – 2006. Supporting this document are the many technical reports and scientific papers that have been generated over the past five years.

In the fifth year of our program, we saw amazing growth in the Radiochemistry Ph.D. program with a total of 12 students in the second year of the program (twice the number we anticipated in the program proposal). In the back of this issue, under Infrastructure Augmentation, you will find some news about the new academic programs sponsored …

Investigation Of Optical Spectroscopy Techniques For On-Line Materials Accountability In The Solvent Extraction Process, Gary Cerefice, Kenneth Czerwinski

Safeguards Campaign (TRP)

The long-term goal of this project is the evaluation of optical spectroscopy-based techniques for the on-line, real-time determination of actinide element concentrations in fuel recycling plant process streams. To generate the information necessary to evaluate the potential of these systems, initial experiments will focus on determining the detection limits for UV/Vis and LFS will be measured for the actinide elements under chemical conditions representative of the process streams for the UREX+ process. The system will then be systematically explored to examine the impact of acid concentration, nitrate concentration, redox potential, diluent concentration, ligand concentration, and contaminant/ fission product concentration on …

Optical Spectroscopy: Quarterly Report: 01/01/06 – 03/31/06, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Safeguards Campaign (TRP)

Progress report for the quarter: laser system alignment finished, site visit scheduled for final spectrometer configuration; initial studies on UO2 2+/NO3 -/H+ completed; preliminary data regression in progress; preliminary work on uranyl/AHA and organic/aqueous interface systems started.

Combined Radiation Detection Methods For Assay Of Higher Actinides In Separation Processes (Afci), Denis Beller, Warnick Kernan

Safeguards Campaign (TRP)

The ultimate objective of this project is to develop technology to detect and accurately measure quantities of higher actinides in processing systems without taking frequent samples. These systems include used fuel receipt, separations batches, and pipelines. A variety of measurements may be combined to calculate flow rates of actinide elements with a to-be-determined precision. Nuclear and decay characteristics of materials during processing will be acquired, conceptual designs of monitoring systems will be developed, radiation transport studies will be conducted to develop an understanding of operational regimes, and experiments will be performed to confirm performance. Radiation transport and scoping studies will …

Neutron Multiplicity Measurements Of Target/Blanket Materials, Denis Beller

Transmutation Sciences Physics (TRP)

The U.S. Advanced Fuel Cycle Initiative (AFCI) is a program to develop economic and environmental methods to reduce the impact of waste from commercial nuclear fuel cycles. One concept for near-complete destruction of waste isotopes from used nuclear fuel is accelerator-driven transmutation. High-power accelerators would be used to produce high-energy charged particles, which then collide with heavy metal targets to create a cascade of neutrons. These neutrons then cause nuclear reactions in subcritical systems.

To design these systems, complex reactor physics computer codes and highly detailed data libraries are used to compute the reactivity of systems, reaction rates, destruction rates, …

Development Of Dose Coefficients For Radionuclides Produced In Spallation Targets, Phillip W. Patton, Mark Rudin

Transmutation Sciences Physics (TRP)

Dose coefficients permit simple determination of radiation dose associated with various exposure scenarios, and ultimately permit radiation safety personnel to assess the health risks to workers in a nuclear facility. Specifically, radiation safety personnel use dose coefficients to determine the radiation dose incurred to a tissue or organ system from a given exposure. These parameters are often expressed in terms of Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACs).

The research consortium comprised of representatives from several universities and national laboratories has successfully generated internal and external dose conversion coefficients for twenty radionuclides produced in spallation neutron sources. …

Reactor Physics Studies For The Afci Reactor-Accelerator Coupling Experiments (Race) Project, Denis Beller

Transmutation Sciences Physics (TRP)

The specific research objective of this three-year project is to design and conduct an accelerator driven experiment. This experiment will help demonstrate in the U.S. the ability to design, compute, and conduct ADSS experiments; and to predict and measure source importance, coupling efficiency, sub-critical reactor kinetics and source-driven transients. In addition, databases will be created for both steady state and transient ADSS experiments for the nuclear community to develop and test new computational codes and methods, and the importance of a driving neutron source in various regions of different subcritical assemblies will be mapped. Experiments will be conducted and compared …

Dissolution, Reactor, And Environmental Behavior Of Zro2-Mgo Inert Fuel Matrix, Kenneth Czerwinski

Fuels Campaign (TRP)

This project examines inert fuels containing ZrO₂ and MgO as the inert matrix, with the relative amount of MgO varied from 30% to 70% in ZrO₂. Reactor physics calculations are used to examine suitable quantities of burnable poisons from the candidate elements Gd, Er, or Hf with reactor grade Pu providing the fissile component, with up to 10% of ²³⁹Pu. Ceramics are synthesized and characterized based on the reactor physics results. The solubility of the fuel ceramics, in reactor conditions, reprocessing conditions, and repository conditions, are investigated in a manner to provide thermodynamic data necessary for …

Impact Of The Synthesis Process On Structure Properties For Afci Fuel Candidates, Thomas Hartmann

Fuels Campaign (TRP)

Advanced Fuel Cycle Initiative research on transmutation fuels includes mono-nitride ceramic fuel forms, and consists of closely coordinated “hot” actinide and “cold” inert and surrogate fuels work. Matrix and surrogate materials work involves three major components: (1) fuel matrix synthesis and fabrication, (2) fuel performance, and (3) fuel materials modeling. The synthesis and fabrication component supports basic material studies, as well as actinide fuel fabrication work through fuel fabrication process development. Fuel performance studies are examining the tolerance of nitride-type fuel to heavy irradiation damage. The fuel materials simulation work involves both atomistic and continuum scale modeling employing first principles, …

Solution-Based Synthesis Of Nitride Fuels, Kenneth Czerwinski, Thomas Hartmann

Fuels Campaign (TRP)

A wide variety of fuel concepts are considered for advanced reactor technology including metals, metal oxides or metal nitrides as solid solutions or composite materials. Nitride fuels have appropriate properties for advanced fuels including high thermal conductivity, thermal stability, solid-state solubility of actinides, fissile metal density, and suitable neutronic properties. A drawback of nitride fuels involves their synthesis. A key parameter for preparing oxide fuels is the precipitation step in the sol-gel process. For nitride fuels, the current synthetic route is carbothermic reduction from the oxide to the nitride. This process step is based on solid phase reactions and for …