Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 83-85).

Throughout the history of the Annular Core Research Reactor (ACRR), Transient Rod (TR) A has experienced an increased rate of failure versus the other two TRs (B and C). Either by pneumatic force or electric motor, the transient rods remove the poison rods from the ACRR core allowing for the irradiation of experiments. In order to develop causes for why TR A is failing (rod break) more often, a better understanding of the whole TR system and its components is needed. This study aims to provide a foundational understanding of how the TR pneumatic system affects the motion of the TRs and the resulting effects that the TR motion has on the neutronics of the ACRR. Transient rod motion profiles have been generated using both experimentally-obtained pressure data and by thermodynamic theory, and input into Razorback, a SNL-developed point kinetics and thermal hydraulics code, to determine the effects that TR timing and pneumatic pressure have on reactivity addition and reactivity feedback. From this study, accurate and precise TR motion profiles have been developed, along with an increased understanding of the pulse timing sequence. With this information, a safety limit within the ACRR was verified for different TR travel lengths and pneumatic system pressures. In addition, longer reactivity addition times have been correlated to cause larger amounts of reactivity feedback. The added clarity on TR motion and timing from this study will pave the way for further study to determine the cause for the increased failure rate of TR A.

Le 16 novembre 1942, dans le désert du Nouveau-Mexique, J. Robert Oppenheimer suggéra à son homologue militaire, le Général Leslie Groves, que la Los Alamos Ranch School d'Ashley Pond serait une localisation idéale pour l'établissement d'un laboratoire secret où continuer la recherche sur la conception et la construction de la bombe atomique. Cet événement scella le destin du Nouveau-Mexique, surnommé la « terre d'enchantement », qui se vit alors octroyé une nouvelle identité en tant que berceau de l'ère nucléaire. Le laboratoire de Los Alamos a déclenché la troisième colonisation de la région : une conquête scientifique financée par le gouvernement fédéral et entretenue par la course à l'armement avec l'Union Soviétique. Le long du Rio Grande, les installations nées à la suite du Projet Manhattan ont révolutionné l'ordre social, économique et démographique établi dans l'État tout en y produisant des bouleversements environnementaux et culturels. Et pourtant, soixante–dix ans plus tard, le Nouveau-Mexique demeurait l'un des cinq États les plus pauvres du pays malgré son Eldorado nucléaire. Cette thèse évalue l'ambivalence et les multiples facettes de l'héritage du Projet Manhattan au Nouveau-Mexique. En estimant la durabilité et la répartition des profits générés par l'industrie nucléaire en termes d'emplois, d'éducation et de niveau de vie, cette thèse interroge l'étendue réelle des gains perçus par les populations locales grâce à cette révolution vers le nucléaire et la haute technologie, ainsi que l'évolution des coûts socio-économiques et environnementaux qu'il a fallu et qu'il faudra encore payer pour la panacée nucléaire. Depuis l'arrivée des premiers pionniers atomiques à Los Alamos, les populations natives du Nouveau-Mexique (qu'il s'agisse des Indiens pueblos, des villageois hispaniques ou des ranchers anglos) ont dû s'adapter aux changements en dents de scie d'un nouvel ordre reposant sur des fonds fédéraux, eux–mêmes déterminés par la scène politique internationale et ils furent confrontés à une concurrence de plus en plus rude avec les nouveaux arrivants, c'est-à-dire les immigrés du nucléaire venant d'autres États. L'association du pouvoir militaire, du gouvernement et de l'omniprésente confidentialité a renforcé les mécanismes du complexe militaro-industriel et scientifique local, ce qui a maintenu la région dans son statut de colonie interne des États-Unis. Depuis les années 1980, une prise de conscience progressive de la société concernant les conséquences environnementales et sanitaires de la radioactivité a entraîné des réactions antinucléaires au Nouveau-Mexique. Dès lors, de nombreuses voix précédemment restées dans le silence se sont levées pour mettre en évidence une autre vision de l'héritage nucléaire dans l'État. Cette perspective locale des participants les plus modestes, les oubliés de l'avènement de l'ère nucléaire, manque de reconnaissance historique. Par conséquent, l'objectif de cette thèse est d'examiner la relation entre ces Nouveaux-Mexicains et l'industrie nucléaire locale. / On November 16, 1942, in the New Mexican desert, J. Robert Oppenheimer suggested to his military counterpart, General Leslie Groves, that Ashley Pond's Los Alamos Ranch School would be an ideal location for the establishment of a secret laboratory to pursue research on the design and construction of the atomic bomb. This event sealed the fate of New Mexico, dubbed the “Land of Enchantment,” which acquired a new identity as the cradle of the nuclear age. The Los Alamos Laboratory paved the way to a third colonization of the area; a scientific conquest funded by the Federal Government and maintained by the arms race with the Soviet Union. Along the Rio Grande, the derivative installations of the Manhattan Project revolutionized the social, economic, and demographic order in the state while introducing environmental and cultural disruptions. And yet, seventy years later, New Mexico was still among the five poorest states in the nation despite its nuclear Eldorado. This thesis assesses the double-edged quality and the multiple facets of the Manhattan Project's legacy in New Mexico. By evaluating the durability and distribution of the benefits entailed by the nuclear industry in terms of jobs, education, and standards of living, this dissertation focuses on the question of the extent to which local populations actually gained from this high-technology revolution, and of the environmental, socio-economic price, which has been and will have to be paid for the nuclear bonanza. Since the settlement of the first atomic pioneers in Los Alamos, the native populations of New Mexico—be they Indian Pueblo dwellers, Hispanic villagers, or Anglo ranchers—have had to adapt to the ups and downs of the new order based on a dependence on federal funds that were, in turn, determined by global politics, and to face an increasingly harsh competition with outsiders, i.e. nuclear immigrants to the state. A combination of military and government power with secrecy built up the mechanism of a local military-industrial and scientific complex, which maintained the region's status as an internal colony of the United States. Since the 1980s, growing public awareness of environmental and health consequences of radioactivity have prompted antinuclear reactions in New Mexico. Thereupon, many previously unheard voices have spoken up to shed a new light on the nuclear heritage in the state. This local perspective of the humblest, forgotten participants in the advent of the nuclear age lacks historical recognition; therefore, the purpose of this dissertation is to address the relations between New Mexicans and the local nuclear industry.

Approved for public release, distribution is unlimited / This thesis analyzes the feasibility, functionality, and usability of Ultra Wideband technology as an alternative to 802.11 in wireless mesh networks for multiple DoD contexts. Ultra wideband and wireless mesh network technologies and applications are researched and analyzed through multiple field and lab experiments for usability in current, real-world situations. Hardware and software investigations are conducted to determine any implementation issues between ultra wideband and wireless mesh networks. A detailed assessment is conducted of the various elements and operational constraints for developing an ultra wideband mesh network that can be utilized to improve situational awareness in network-centric operations. Through joint research with Lawrence Livermore National Laboratories, various hardware and software components are developed to create a test bed for tactical level ultra wideband and mesh networking experimentation in a highly mobile environment. This thesis also lays the groundwork into future ultra wideband and mesh networking applications. / Lieutenant, United States Navy

No description available.

This work seeks to illustrate the potential benefits afforded by implementing aspects of fluid dynamics, especially the latest computational fluid dynamics (CFD) modeling approach, through numerical experimentation and the traditional discipline of physical experimentation to improve the calibration of the severe reactor accident analysis code, MELCOR, in one of several spent fuel pool (SFP) complete loss-of-coolant accident (LOCA) scenarios. While the scope of experimental work performed by Sandia National Laboratories (SNL) extends well beyond that which is reasonably addressed by our allotted resources and computational time in accordance with initial project allocations to complete the report, these simulated case trials produced a significant array of supplementary high-fidelity solutions and hydraulic flow-field data in support of SNL research objectives. Results contained herein show FLUENT CFD model representations of a 9x9 BWR fuel assembly in conditions corresponding to a complete loss-of-coolant accident scenario. In addition to the CFD model developments, a MATLAB based control-volume model was constructed to independently assess the 9x9 BWR fuel assembly under similar accident scenarios. The data produced from this work show that FLUENT CFD models are capable of resolving complex flow fields within a BWR fuel assembly in the realm of buoyancy-induced mass flow rates and that characteristic hydraulic parameters from such CFD simulations (or physical experiments) are reasonably employed in corresponding constitutive correlations for developing simplified numerical models of comparable solution accuracy. / text