Evaluation of methods for seismic analysis of mixed-oxide fuel fabrication plants

Guidelines are needed for selecting appropriate methods of structural analyses to evaluate the seismic hazard of mixed-oxide fuel fabrication plants. This study examines the different available methods and their applicability to fabrication plants. These results should provide a basis for establishing guidelines recommending methods of analysis to ensure safe design against seismic hazards. Using the Westinghouse Recycle Fuels Plant as representative of future mixed-oxide fuel fabrication plants, critical structures and equipment (systems, components, and piping/ducting) were identified. These included the manufacturing building and 11 different pieces of equipment. After examination of the dynamic response characteristics of the building and the different methods available to analyze equipment, appropriate methods of analyses were recommended. Because critical equipment analysis and test methods generally use floor-response spectra as their seismic input loading, several methods used to generate floor spectra were also examined. These include the time-history approach and the Kapur and Biggs approximate methods. The examination included the effect of site characteristics and both horizontal and vertical structural response. (auth

BE Ursae Majoris: A detached binary with a unique reprocessing spectrum

New infrared photometry, optical and UV spectrophotometry, and a photographic ephemeris are presented for the detached binary BE UMa. Results show the primary to be a DO white dwarf with an effective temperature of 80,000 + or - 15,000 K and a mass of 0.6 + or - 0.1 solar masses. No evidence is found for variability of the primary. The main sequence secondary star is shown to be of early M spectral type, with a formal range of M1 to M5 being possible. A reflection effect in reprocessed line and continuum radiation is produced by EUV radiation from the primary incident on the secondary atmosphere. It is suggested that the temperature of the reprocessed component of the secondary's atmosphere is in the 5000 to 8500 K range, and that emission lines of decreasing ionization form deeper in the irradiated envelope. Relatively narrow He II and high excitation metal lines are formed from recombination and continuum fluorescence processes

Legal Education at a Crossroads: Innovation, Integration, and Pluralism Required!

We conclude in this Article that expanded practice-based, experiential education will provide foundational learning for the successful transition from law student to law practice, and that clinical education (in-house clinics, hybrid clinics, and externships) is crucial to the preparation of competent, ethical law graduates who are ready to become professionals. We urge law schools to require each graduate complete a minimum of twenty-one experiential course credits over the three years of law school, including at least five credits in law clinics or externships. Twenty-one required credits (or roughly 25 percent of the eighty-three required credits for graduation from an American Bar Association (ABA)-approved law school) would bring legal education closer to, although still below, the experiential and clinical education course requirements of other professions

Legal Education at a Crossroads: Innovation, Integration, and Pluralism Required!

We conclude in this Article that expanded practice-based, experiential education will provide foundational learning for the successful transition from law student to law practice, and that clinical education (in-house clinics, hybrid clinics, and externships) is crucial to the preparation of competent, ethical law graduates who are ready to become professionals. We urge law schools to require each graduate complete a minimum of twenty-one experiential course credits over the three years of law school, including at least five credits in law clinics or externships. Twenty-one required credits (or roughly 25 percent of the eighty-three required credits for graduation from an American Bar Association (ABA)-approved law school) would bring legal education closer to, although still below, the experiential and clinical education course requirements of other professions

Seismic Safety Study

During the past three decades, the Laboratory has been proactive in providing a seismically safe working environment for its employees and the general public. Completed seismic upgrades during this period have exceeded $30M with over 24 buildings structurally upgraded. Nevertheless, seismic questions still frequently arise regarding the safety of existing buildings. To address these issues, a comprehensive study was undertaken to develop an improved understanding of the seismic integrity of the Laboratory's entire building inventory at the Livermore Main Site and Site 300. The completed study of February 2005 extended the results from the 1998 seismic safety study per Presidential Executive Order 12941, which required each federal agency to develop an inventory of its buildings and to estimate the cost of mitigating unacceptable seismic risks. Degenkolb Engineers, who performed the first study, was recontracted to perform structural evaluations, rank order the buildings based on their level of seismic deficiencies, and to develop conceptual rehabilitation schemes for the most seriously deficient buildings. Their evaluation is based on screening procedures and guidelines as established by the Interagency Committee on Seismic Safety in Construction (ICSSC). Currently, there is an inventory of 635 buildings in the Laboratory's Facility Information Management System's (FIMS's) database, out of which 58 buildings were identified by Degenkolb Engineers that require seismic rehabilitation. The remaining 577 buildings were judged to be adequate from a seismic safety viewpoint. The basis for these evaluations followed the seismic safety performance objectives of DOE standard (DOE STD 1020) Performance Category 1 (PC1). The 58 buildings were ranked according to three risk-based priority classifications (A, B, and C) as shown in Figure 1-1 (all 58 buildings have structural deficiencies). Table 1-1 provides a brief description of their expected performance and damage state following a major earthquake, rating the seismic vulnerability (1-10) where the number 10 represents the highest and worst. Buildings in classifications A and B were judged to require the Laboratory's highest attention towards rehabilitation, classification C buildings could defer rehabilitation until a major remodel is undertaken. Strengthening schemes were developed by Degenkolb Engineers for the most seriously deficient A and B classifications (15 total), which the Laboratory's Plant Engineering Department used as its basis for rehabilitation construction cost estimates. A detailed evaluation of Building 2580, a strengthening scheme, and a construction cost estimate are pending. Specific details of the total estimated rehabilitation costs, a proposed 10-year seismic rehabilitation plan, exemption categories by building, DOE performance guidelines, cost comparisons for rehabilitation, and LLNL reports by Degenkolb Engineers are provided in Appendix A. Based on the results of Degenkolb Engineers evaluations, along with the prevailing practice for the disposition of seismically deficient buildings and risk-based evaluations, it is concluded that there is no need to evacuate occupants from these 58 buildings prior to their rehabilitation

Overview of crash and impact analysis at Lawrence Livermore National Laboratory

This work provides a brief overview of past and ongoing efforts at Lawrence Livermore National Laboratory (LLNL) in the area of finite-element modeling of crash and impact problems. The process has been one of evolution in several respects. One aspect of the evolution has been the continual upgrading and refinement of the DYNA, NIKE, and TOPAZ family of finite-element codes. The major missions of these codes involve problems where the dominant factors are high-rate dynamics, quasi-statics, and heat transfer, respectively. However, analysis of a total event, whether it be a shipping container drop or an automobile/barrier collision, may require use or coupling or two or more of these codes. Along with refinements in speed, contact capability, and element technology, material model complexity continues to evolve as more detail is demanded from the analyses. A more recent evolution has involved the mix of problems addressed at LLNL and the direction of the technology thrusts. A pronounced increase in collaborative efforts with the civilian and private sector has resulted in a mix of complex problems involving synergism between weapons applications (shipping container, earth penetrator, missile carrier, ship hull damage) and a more broad base of problems such as vehicle impacts as discussed herein

A Unique Concept for Liquid Level and Void Fraction Detection in Severe Fuel Damage Tests

This report describes a direct-contacting liquid level and void fraction detection system that is being developed by Pacific Northwest Laboratory. The measurement technique could be used in the severe fuel damage tests that will be conducted at the Power Burst Facility, Idaho Falls, Idaho, and at the ESSOR reactor, Ispra, Italy. The detection system could also be retrofitted for commercial operating reactors to provide definitive thermal-hydraulic information. The technique can provide unambiguous, real-time data on liquid level and void fraction during normal reactor operation as well as during shutdown and accident conditions