In this study, we limited our questions to ORNL, discussing their models with almost a dozen staff members from four divisions. We collected some low-level data about the models, and also tried to gain a sense of the philosophy of the modeler, and how each model fit into the larger perspective of ORNL`s and the scientific community`s efforts. Time and budget prevented us from conducting any larger study, but we have no reason to suppose that conclusions about ORNL`s models and modelers could not be extended to the larger scientific community.

We report on the design details of the first ultraviolet (UV) free-electron laser (FEL) oscillator driven by low-energy electrons from a radio-frequency linear accelerator. In our experiment we used a high-current, high brightness electon beam in combination with a wiggler of novel design to produce an FEL that lased at wavelengths from 369--380 nm using 45.9--45.2 MeV electrons. In addition we performed a proof-of principle experiment that demonstrated the first ever photolithography on a photoresist-coated silicon wafer using an FEL light source.

Many workstation based emergency response dispersion modeling systems provide simple Gaussian models driven by single meteorological tower inputs to estimate the downwind consequences from accidental spills or stack releases. Complex meteorological or terrain settings demand more sophisticated resolution of the three-dimensional structure of the atmosphere to reliably calculate plume dispersion. Mountain valleys and sea breeze flows are two common examples of such settings. To address these complexities, we have implemented the three-dimensional-diagnostic MATHEW mass-adjusted wind field and ADPIC particle-in-cell dispersion models on a workstation for use in real-time emergency response modeling. Both MATHEW and ADPIC have shown their utility in a variety of complex settings over the last 15 years within the Department of Energy`s Atmospheric Release Advisory Capability project.

A number of anomalies have been observed for fissile material arrays. This paper will review anomalous behavior associated with interstitial array moderation and correct one previously-mis-identified anomaly. Most arrays show a maximum k{sub eff} with low-density water moderation. An earlier study, however, did not show this maximum for unreflected 5{times}5{times}5 and 10{times}10{times}10 arrays of 15-kg {sup 235}U spheres. Our present calculations with MCNP and KENO V.a, however, show low-density maximums for both unreflected and reflected arrays of these units. We conclude that the earlier calculations for unreflected arrays were in error -- perhaps due to problem setup or code errors. The reactivity enhancement due to fissile material density reductions, however, still exits and is now seen to occur for both unreflected and water-reflected arrays.

Longitudinal space-charge waves develop on heavy-ion inertial-fusion pulse from initial mismatches or from inappropriately timed or shaped accelerating voltages. Without correction, waves moving backward along the beam can grow due to the interaction with their resistively retarded image fields, eventually degrading the longitudinal emittance. A simple correction algorithm is presented here that uses a time-dependent axial electric field to reverse the direction of backward-moving waves. The image fields then damp these forward-moving waves. The method is demonstrated by fluid simulations of an idealized inertial-fusion driver, and practical problems in implementing the algorithm are discussed.

The increasing emphasis on envirorunental issues, waste reduction, and improved efficiency for industrial processes has mandated the development of new chemical and physical sensors for field or in-plant use. The Lawrence Livermore National Laboratory (LLNL) has developed a number of technologies for sensing physical and chemical properties. Table 1 gives some examples of several sensors. that have been developed recently for environmental, industrial, commercial or government applications. Physical sensors of pressure, temperature, acceleration, acoustic vibration spectra, and ionizing radiation have been developed. Sensors developed at LLNL for chemical species include inorganic solvents, heavy metal ions`, and gaseous atoms and compounds. Primary sensing technologies we have employed have been based on optical fibers, semiconductor optical or radiation detectors, electrochemical activity, micromachined electromechanical (MEMs) structures, or chemical separation technologies. The complexities of these sensor systems range from single detectors to more advanced micro-instruments on-a-chip. For many of the sensors we have developed the necessary intelligent electronic support systems for both local and remote sensing applications. Each of these sensor technologies are briefly described in the remaining sections of this paper.

No endeavor is risk-fire and as we realize the inherent risks in society, our only viable solution is to manage the risk. Application of an integrated risk management program of a large technological system like the DOE complex is a difficult, task; but it is the only rational means to optimize the risk-benefit equation. An effective risk management culture-within the DOE complex will in the long run, ensure a consistent response to mitigate identified risks. An effective risk management program provides responsible administrative planning and logical application of the best technical analyses. It requires the involvement of all personnel. Our objective in this paper is to point out broad perspectives that raise concerns about future DOE ask management issues and to suggest some possible remedies.

The fracture toughness of brittle intermetallic compounds can be improved by ductile-phase reinforcements. Effectiveness of the ductile phase in bridging cracks, and therefore increasing, the composite toughness, is known qualitatively to depend upon the extent of debonding, between the two phases. Numerical crack-growth simulations are used here to provide semi-quantitative predictions of the influence of interfacial debonding on the macroscopic stress-displacement behavior and, hence, the fracture toughness of an idealized Pb/glass composite. The interfacial toughness required to cause debonding, characterized by a constant critical energy release rate, is varied parametrically. As expected, higher interfacial toughness results in less interphase debonding, higher composite strength, and greater ductile-phase constraint. Consequently, the increase in ductile-phase triaxiality can potentially accelerate internal void formation and growth or facilitate cleavage fracture, either of which would likely decrease the toughness of the composite.

There is no technical basis for setting a time limit of 10,000 years on the regulated performance of a nuclear waste repository. First, accurate prediction of releases for such periods is not possible. Second, there is nothing unique about 10,000 years. Third, equally toxic materials, which never transform to non-toxic substances by radioactive decay, have no long-term requirements. And fourth, over a 10,000 year time frame, social and natural disasters will dwarf the worst possible outcomes of repository placement. Analyses could be required to extend as long as doses above current radiation protection guidelines are possible (perhaps several million years), but these results should be recognized as qualitative information rather than evidence of quantitative compliance with exact numerical limits. Concern for what will happen over long times can be addressed for the next several hundred years by maintaining waste retrievability. At that time, uncertainty about future performance should have been reduced significantly.

HIPROTECT (pronounced High-protect) is a system designed to protect national archaeological and natural treasures from destruction by vandals or looters. The system is being developed jointly by the Lawrence Livermore National Laboratory and the University of California at Riverside under the DOD Legacy Resource Management Program. Thousands of archaeological sites are located on military bases and national park lands. Treasure hunters or vandals are pillaging and destroying these sites at will, since the sites are generally located in remote areas, unattended and unprotected. The HIPROTECT system is designed to detect trespassers at the protected sites and to alert park officials or military officials of intrusions. An array of sensors is used to detect trespassers. The sensors are triggered when a person or vehicle approaches the site. Alarm messages are transmitted to alert park officials or law enforcement officials by way of a cellular telephone link. A video and audio system is included to assist the officials in verifying that an intrusion has occurred and to allow two-way communication with the intruders.

High energy electron beams (HEEBs) with megavolt energies represent a new generation of charged particle beams that rapidly deposit up to several hundred joules/pulse over areas on the order of a few square millimeters to 100s of square centimeters. These pulsed beams have energies in the 1 to 10 MeV range, which enables the electrons to deposit large amounts of energy deeply into the material being processed, and these beams have short pulse durations (50 ns) that can heat materials at rates as high as 10{sup 10} {degrees}C/s for a 1000 {degree}C temperature rise in the material. Lower heating rates, on the order of 10{sup 4} {degrees}C/s, can be produced by reducing the energy per pulse and distributing the total required energy over a series of sub-ms pulses, at pulse repetition frequencies (PRFs) up to several kHz. This paper presents results from materials processing experiments performed on steel with a 6 MeV electron beam, analyzes these results using a Monte Carlo transport code, and presents a first-order predictive method for estimating the peak energy deposition, temperature, and heating rate for HEEB processed steel.