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Statement of David E. Baldwin, Associate Director for Energy, Lawrence Livermore National Laboratory and John C. Crawford, Vice President, Sandia National Laboratories, California, to the Subcommittee on Research and Development of the Committee on Environment and Public Works, United States Senate, Washington, DC, March 22, 1993 (open access)

Statement of David E. Baldwin, Associate Director for Energy, Lawrence Livermore National Laboratory and John C. Crawford, Vice President, Sandia National Laboratories, California, to the Subcommittee on Research and Development of the Committee on Environment and Public Works, United States Senate, Washington, DC, March 22, 1993

Testimony was submitted to the Senate on the environmental impacts of accelerated research and development of hydrogen-based energy systems. The advantages of hydrogen in transportation systems, in fuel cells for electric vehicles and power plants, and in energy storage from off-peak electricity production were described. The largest barrier to using hydrogen in the transportation sector is the on-board storage of enough fuel to provide an adequate driving range in an urban environment. Production methods and costs were also discussed. The authors believe a coordinated demonstration program with US industry is needed to develop the best technologies for hydrogen-fueled vehicles.
Date: March 18, 1993
Creator: Baldwin, D. E. & Crawford, J. C.
System: The UNT Digital Library
Limits on high-order harmonic generation from single-atom calculations (open access)

Limits on high-order harmonic generation from single-atom calculations

In the quantum mechanical calculations of electron and photon emission from atoms in strong laser fields we have employed a single-active-electron (SAE) model. We determine the effect of the time varying electric field of the laser on each of the valence electrons separately. The active electron in each calculation moves in the time-independent mean field of the remaining, unexcited electrons and the nucleus. This approach works well for the rare gas atoms, at least partially because the neglected double or higher excitations involve states well above the ionization threshold. The photoelectron and photon emission spectra calculated using this technique agree quantitatively with observed emission rates. In this paper we will present a simple semiclassical model for high intensity ionization which reproduces the observed harmonic emission spectra obtained in this regime and which provides considerable insight into the dynamics of this process. The basic models has been used in the past to predict electron energy distributions in the tunneling regime and we will use it here for harmonics.
Date: August 18, 1993
Creator: Kulander, K. C. & Schafer, K. J.
System: The UNT Digital Library
Generation of harmonic radiation using the multi-cavity free-electron laser (open access)

Generation of harmonic radiation using the multi-cavity free-electron laser

An FEL provides a convenient method of reaching short wavelengths by resonating with an input source at the fundamental wavelength while providing bunching at a harmonic of the fundamental. Recently schemes have been proposed that use two wiggler segments, one resonant at the fundamental to pre-bunch the beam, the other lasing at the desired (third) harmonic. A similar effect, with some advantages and some disadvantages, can be achieved using the Multi-Cavity FEL (MC/FEL). The MC/FEL employs several short cavities, operating in an oscillator-like manner, to achieve high output power. In this paper we consider the use of the MC/FEL as a means of generating harmonics. We investigate the competitiveness of this option in comparison with other harmonic generation schemes, in terms of the total wiggler length needed, the saturated power achieved, and the restrictions imposed by mirror reflectivity.
Date: August 18, 1993
Creator: Krishnagopal, S. & Sessler, A. M.
System: The UNT Digital Library
Environmental restoration and decontamination & decommissioning safety documentation. Revision 2 (open access)

Environmental restoration and decontamination & decommissioning safety documentation. Revision 2

This document presents recommendations of a working group designated by the Environmental Restoration and Remediation (ER) and Decontamination and Decommissioning (D&D) subcommittees of the Westinghouse M&O (Management and Operation) Nuclear Facility Safety Committee. A commonalty of approach to safety documentation specific to ER and D&D activities was developed and is summarized below. Allowance for interpretative tolerance and documentation flexibility appropriate to the activity, graded for hazard category, duration, and complexity, was a primary consideration in development of this guidance.
Date: May 18, 1993
Creator: Hansen, J. L.; Frauenholz, L. H. & Kerr, N. R.
System: The UNT Digital Library
Incorporating long-term climate change in performance assessment for the Waste Isolation Pilot Plant (open access)

Incorporating long-term climate change in performance assessment for the Waste Isolation Pilot Plant

The United States Department of Energy (DOE) is developing the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico for the disposal of transuranic wastes generated by defense programs. Applicable regulations (40 CFR 191) require the DOE to evaluate disposal-system performance for 10,000 yr. Climatic changes may affect performance by altering groundwater flow. Paleoclimatic data from southeastern New Mexico and the surrounding area indicate that the wettest and coolest Quaternary climate at the site can be represented by that at the last glacial maximum, when mean annual precipitation was approximately twice that of the present. The hottest and driest climates have been similar to that of the present. The regularity of global glacial cycles during the late Pleistocene confirms that the climate of the last glacial maximum is suitable for use as a cooler and wetter bound for variability during the next 10,000 yr. Climate variability is incorporated into groundwater-flow modeling for WIPP PA by causing hydraulic head in a portion of the model-domain boundary to rise to the ground surface with hypothetical increases in precipitation during the next 10,000 yr. Variability in modeled disposal-system performance introduced by allowing head values to vary over this range is insignificant compared to …
Date: September 18, 1993
Creator: Swift, P. N.; Baker, B. L.; Economy, K.; Garner, J. W.; Helton, J. C. & Rudeen, D. K.
System: The UNT Digital Library
Parametric variations of ion transport in TFTR (open access)

Parametric variations of ion transport in TFTR

This paper is divided into three roughly independent sections. The first is a historical review of the twenty year history of experimental ion heat transport measurements from many tokamaks. The second is a study of ion heat transport in Ohmic TFTR plasmas which shows that {chi}i {approximately} {chi}e {approx} 15{chi}i{sup neo}. Thus, ion heat transport is demonstrated to be strongly anomalous even the absence of auxiliary heating. The third section describes the variation of {chi}i with local ion temperature in TFTR during auxiliary heating, with emphasis on characterizing the differecens between transport in the L-mode and supershot regimes. The results are consistent with the conjecture that improved ion energy confinement in supershot plasmas is caused by a high ratio of T{sub 1}/T{sub e}.
Date: March 18, 1993
Creator: Scott, S. D.; Barnes, C. W. & Ernst, D.
System: The UNT Digital Library
Technology development for recirculating heavy-ion accelerators (open access)

Technology development for recirculating heavy-ion accelerators

The {open_quotes}recirculator,{close_quotes} a recirculating heavy-ion accelerator has been identified as a promising approach for an inertial fusion driver. System studies have been conducted to evaluate the recirculator on the basis of feasibility and cost. The recirculator has been shown to have significant cost advantages over other potential driver schemes, but some of the performance requirements exceed the capabilities of present technology. The system studies identified the high leverage areas where advances in technology will significantly impact the cost and performance of a recirculator. One of the high leverage areas is the modulator system which generates the acceleration potentials in the induction cells. The modulator system must be capable of generating the acceleration potentials at peak repetition rates in excess of 100 kHz with variable pulse widths. LLNL is developing a modulator technology capable of driving induction cells using the latest in solid state MOSFET technology. A small scale modulator has been built and tested to prove the concept and the next version is presently being designed. The objective is to demonstrate a modulator operating at 5 kV, 1 kA, with 0.2--1 {mu}s pulse widths while driving an induction cell at >100 kHz within the next year. This paper describes the …
Date: May 18, 1993
Creator: Newton, M. A. & Kirbie, H. C.
System: The UNT Digital Library
Fundamental theory of light for applications: Notes for five informal lectures (open access)

Fundamental theory of light for applications: Notes for five informal lectures

These notes give an overview of some aspects of the quantum theory of light and its interaction with matter. A description is given of basic emission and absorption processes, as well as the theory of photodetection and optical coherence. Basic research in this area is increasingly relevant to areas of technological importance, including microlaser devices and the noise characteristics of semiconductor lasers.
Date: June 18, 1993
Creator: Milonni, P. W.
System: The UNT Digital Library
Large-scale testing of structural clay tile infilled frames (open access)

Large-scale testing of structural clay tile infilled frames

A summary of large-scale cyclic static tests of structural clay tile infilled frames is given. In-plane racking tests examined the effects of varying frame stiffness, varying infill size, infill offset from frame centerline, and single and double wythe infill construction. Out-of-plane tests examined infilled frame response to inertial loadings and inter-story drift loadings. Sequential in-plane and out-of-plane loadings were performed to determine the effects of orthogonal damage and degradation on both strength and stiffness. A combined out-of-plane inertial and in-plane racking test was conducted to investigate the interaction of multi-directional loading. To determine constitutive properties of the infills, prism compression, mortar compression and various unit tile tests were performed.
Date: March 18, 1993
Creator: Flanagan, R. D. & Bennett, R. M.
System: The UNT Digital Library
The role of heating and current drive in ITER (open access)

The role of heating and current drive in ITER

This report discusses and summarize the role of heating and non-inductive current drive in ITER as: (1) ITER must have heating power sufficient for ignition. (2) The heating system must be capable of current drive. (3) Steady-state operation is an ``ultimate goal.`` It is recognized that additional heating and current drive power (beyond what is initially installed on ITER) may be required. (4) The ``Ultimate goal of steady-state operation`` means steady-state with Q{sub CD} {ge} 5. Unlike the ``Terms of Reference`` for the ITER CDA, the ``ITER Technical Objectives and Approaches`` for the EDA sets no goal for the neutron wall load during steady-state operation. (5) In addition to bulk current drive, the ITER heating and current drive system should be used for current profile control and for burn control.
Date: October 18, 1993
Creator: Nevins, W. M. & Haney, S.
System: The UNT Digital Library
Neutron streaming through shield ducts using a discrete ordinates/Monte Carlo method (open access)

Neutron streaming through shield ducts using a discrete ordinates/Monte Carlo method

A common problem in shield design is determining the neutron flux that streams through ducts in shields and also that penetrates the shield after having traveled partway down the duct. Obviously the determination of the neutrons that stream down the duct can be computed in a straightforward manner using Monte Carlo techniques. On the other hand those neutrons that must penetrate a significant portion of the shield are more easily handled using discrete ordinates methods. A hybrid discrete ordinates/Monte Carlo cods, TWODANT/MC, which is an extension of the existing discrete ordinates code TWODANT, has been developed at Los Alamos to allow the efficient, accurate treatment of both streaming and deep penetration problems in a single calculation. In this paper we provide examples of the application of TWODANT/MC to typical geometries that are encountered in shield design and compare the results with those obtained using the Los Alamos Monte Carlo code MCNP{sup 3}.
Date: August 18, 1993
Creator: Urban, W. T. & Baker, R. S.
System: The UNT Digital Library
Fundamental theory of light for applications: Notes for five informal lectures (open access)

Fundamental theory of light for applications: Notes for five informal lectures

These notes give an overview of some aspects of the quantum theory of light and its interaction with matter. A description is given of basic emission and absorption processes, as well as the theory of photodetection and optical coherence. Basic research in this area is increasingly relevant to areas of technological importance, including microlaser devices and the noise characteristics of semiconductor lasers.
Date: June 18, 1993
Creator: Milonni, P.W.
System: The UNT Digital Library