Underground nuclear power plant siting

This study is part of a larger evaluation of the problems associated with siting nuclear power plants in the next few decades. This evaluation is being undertaken by the Environmental Quality Laboratory of the California Institute of Technology in conjunction with The Aerospace Corporation and several other organizations. Current efforts are directed toward novel approaches to siting plants within the State of California. This report contains the results of efforts performed by The Aerospace Corporation to provide input information to the larger evaluation relative to underground siting of large central station nuclear power plants. Projections of electric power demand in California and the country as a whole suggest that a major increase in generating capacity will be required. The problem is complicated beyond that of a large but straightforward extension of capital investment by increased emphasis on environmental factors combined with the early stage of commercial application and regulation of nuclear power sources. Hydroelectric power generation is limited by the availability of suitable sites, and fossil fueled plants are constrained by the availability of high quality fuels and the adverse environmental and/or economic impact from the use of more plentiful fuels. A substantial increase in the number of nuclear power plants is now under way. This source of power is expected to provide the maj or portion of increased capacity. Other power sources such as geothermal and nuclear fusion are unlikely to satisfy the national needs due to technical problems and the lack of a comprehensive development program. There are several problems associated with meeting the projected power demand. Chief among these is the location of acceptable and economic plant sites. Indeed a sufficient number of sites may not be found unless changes occur in the procedures for selecting sites, the criteria for accepting sites, or the type of site required. Placement of a nuclear plant underground has been suggested as an alternative to present siting practices. It is postulated that the advantages of underground siting in some situations may more than compensate for added costs so that such facilities could be preferred even where surface sites are available. By virtue of greater safety, reduced surface area requirements, and improved aesthetics, underground sites might also be found where acceptable surface sites are not available. Four small European reactors have been constructed partially underground but plans for large size commercial plants have not progressed. Consequently, the features of underground power plant siting are not well understood. Gross physical features such as depth of burial, number and size of excavated galleries, equipment layout, and access or exit shafts/tunnels must be specified. Structural design features of the gallery liners, containment structure, foundations, and gallery interconnections must also be identified. Identification of the nuclear, electrical, and support equipment appropriate to underground operation is needed. Operational features must be defined for normal operations, refueling, and construction. Several magazine articles have been published addressing underground concepts. but adequate engineering data is not available to support an evaluation of the underground concept. There also remain several unresolved questions relative to the advantages of underground siting as well as the costs and other possible penalties associated with this novel approach to siting. These include the degree of increased safety through improved containment; the extent and value of isolation from falling objects, e. g. aircraft; the value of isolation from surface storms and tidal waves; the value of protection from vandalism or sabotage; the extent by which siting constraints are relieved through reduced population-distance requirements or aggravated by underground construction requirements; and the value to be placed upon the aesthetic differences of a less visible facility. The study described in this report has been directed toward some of these questions and uncertainties. Within the study an effort has been made to identify viable configurations and structural liners for typical light water reactor nuclear power plants. Three configurations are summarized in Section 3. A discussion of the underground gallery liner design and associated structural analyses is presented in Section 4. Also addressed in the study and discussed in Section 5 are some aspects of containment for underground plants. There it is suggested that the need for large separations between the plant and population centers may be significantly reduced, or perhaps eliminated. Section 6 contains a brief discussion of operational considerations for underground plants. The costs associated with excavation and lining of the underground galleries have been estimated in Section 7. These estimates include an assessment of variations implied by different seismic loading assumptions and differences in geologic media. It is shown that these costs are a small percentage of the total cost of comparable surface plants. Finally, the parameters characterizing an acceptable underground site are discussed in Section 8. Material is also included in the appendices pertaining to foreign underground plants, span limits of underground excavations, potential siting areas for underground plants in the State of California, pertinent data from the Underground Nuclear Test Program, and other supporting technical discussions

Population policies and education: exploring the contradictions of neo-liberal globalisation

The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives

Large-Scale Atomistic Simulations of Environmental Effects on the Formation and Properties of Molecular Junctions

Using an updated simulation tool, we examine molecular junctions comprised of benzene-1,4-dithiolate bonded between gold nanotips, focusing on the importance of environmental factors and inter-electrode distance on the formation and structure of bridged molecules. We investigate the complex relationship between monolayer density and tip separation, finding that the formation of multi-molecule junctions is favored at low monolayer density, while single-molecule junctions are favored at high density. We demonstrate that tip geometry and monolayer interactions, two factors that are often neglected in simulation, affect the bonding geometry and tilt angle of bridged molecules. We further show that the structures of bridged molecules at 298 and 77 K are similar.Comment: To appear in ACS Nano, 30 pages, 5 figure

Current polarity-dependent manipulation of antiferromagnetic domains

Antiferromagnets have several favourable properties as active elements in spintronic devices, including ultra-fast dynamics, zero stray fields and insensitivity to external magnetic fields. Tetragonal CuMnAs is a testbed system in which the antiferromagnetic order parameter can be switched reversibly at ambient conditions using electrical currents. In previous experiments, orthogonal in-plane current pulses were used to induce 90° rotations of antiferromagnetic domains and demonstrate the operation of all-electrical memory bits in a multi-terminal geometry. Here, we demonstrate that antiferromagnetic domain walls can be manipulated to realize stable and reproducible domain changes using only two electrical contacts. This is achieved by using the polarity of the current to switch the sign of the current-induced effective field acting on the antiferromagnetic sublattices. The resulting reversible domain and domain wall reconfigurations are imaged using X-ray magnetic linear dichroism microscopy, and can also be detected electrically. Switching by domain-wall motion can occur at much lower current densities than those needed for coherent domain switching

Rare copy number variation in cerebral palsy

As per publisher: published online 22 May 2013Recent studies have established the role of rare copy number variants (CNVs) in several neurological disorders but the contribution of rare CNVs to cerebral palsy (CP) is not known. Fifty Caucasian families having children with CP were studied using two microarray designs. Potentially pathogenic, rare (<1% population frequency) CNVs were identified, and their frequency determined, by comparing the CNVs found in cases with 8329 adult controls with no known neurological disorders. Ten of the 50 cases (20%) had rare CNVs of potential relevance to CP; there were a total of 14 CNVs, which were observed in <0.1% (<8/8329) of the control population. Eight inherited from an unaffected mother: a 751-kb deletion including FSCB, a 1.5-Mb duplication of 7q21.13, a 534-kb duplication of 15q11.2, a 446-kb duplication including CTNND2, a 219-kb duplication including MCPH1, a 169-kb duplication of 22q13.33, a 64-kb duplication of MC2R, and a 135-bp exonic deletion of SLC06A1. Three inherited from an unaffected father: a 386-kb deletion of 12p12.2-p12.1, a 234-kb duplication of 10q26.13, and a 4-kb exonic deletion of COPS3. The inheritance was unknown for three CNVs: a 157-bp exonic deletion of ACOX1, a 693-kb duplication of 17q25.3, and a 265-kb duplication of DAAM1. This is the first systematic study of CNVs in CP, and although it did not identify de novo mutations, has shown inherited, rare CNVs involving potentially pathogenic genes and pathways requiring further investigation.Gai McMichael, Santhosh Girirajan, Andres Moreno-De-Luca, Jozef Gecz, Chloe Shard, Lam Son Nguyen, Jillian Nicholl, Catherine Gibson, Eric Haan, Evan Eichler, Christa Lese Martin and Alastair MacLenna

Aortic valvuloplasty of calcific aortic stenosis with monofoil and trefoil balloon catheters: practical considerations

In order to evaluate the relation between balloon design (monofoil, trefoil) and valvular configuration, experimental aortic valvuloplasty was performed in four post-mortem hearts with calcific aortic sten

Late Holocene climate: Natural or anthropogenic?

For more than a decade, scientists have argued about the warmth of the current interglaciation. Was the warmth of the preindustrial late Holocene natural in origin, the result of orbital changes that had not yet driven the system into a new glacial state? Or was it in considerable degree the result of humans intervening in the climate system through greenhouse gas emissions from early agriculture? Here we summarize new evidence that moves this debate forward by testing both hypotheses. By comparing late Holocene responses to those that occurred during previous interglaciations (in section 2), we assess whether the late Holocene responses look different (and thus anthropogenic) or similar (and thus natural). This comparison reveals anomalous (anthropogenic) signals. In section 3, we review paleoecological and archaeological syntheses that provide ground truth evidence on early anthropogenic releases of greenhouse gases. The available data document large early anthropogenic emissions consistent with the anthropogenic ice core anomalies, but more information is needed to constrain their size. A final section compares natural and anthropogenic interpretations of the δ13C trend in ice core CO2

Haboob Dust Storms and Motor Vehicle Collision-related Trauma in Phoenix, Arizona

Background: The Sonoran Desert region, encompassing most of southern Arizona, has an extreme climate that is famous for dust storms known as haboobs. These storms lead to decreased visibility and potentially hazardous driving conditions. In this study we evaluate the relationship between haboob events and emergency department (ED) visits due to motor vehicle collisions (MVCs) in Phoenix, Arizona.Methods: This study is a retrospective analysis of MVC-related trauma presentations to Phoenix, AZ, hospitals before and following haboob dust storms. These events were identified from 2009–2017 primarily using Phoenix International Airport weather data. De-identified trauma data were obtained from the Arizona Department of Health Services (ADHS) Arizona State Trauma Registry (ASTR) from seven trauma centers within a 10-mile radius of the airport. We compared MVC-related trauma using six- and 24-hour windows before and following the onset of haboob events.Results: There were 31,133 MVC-related trauma encounters included from 2009–2017 and 111 haboob events meeting meteorological criteria during that period. There was a 17% decrease in MVC-related ED encounters in the six hours following haboob onset compared to before onset (235 vs 283, P = 0.04), with proportionally more injuries among males (P &lt; 0.001) and higher mortality (P = 0.02). There was no difference in frequency of presentations (P = 0.82), demographics, or outcomes among the 24-hour pre-and post-haboob groups.Conclusion: Haboob dust storms in Phoenix, Arizona, are associated with a decrease in MVC-related injuries during the six-hour period following storm onset, likely indicating the success of public safety messaging efforts. Males made up a higher proportion of those injured during the storms, suggesting a target for future interventions. Future public-targeted weather-safety initiatives should be accompanied more closely by monitoring and evaluation efforts to assess for effectiveness

Food for pollinators: quantifying the nectar and pollen resources of urban flower meadows

Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many ‘pollinator-friendly’ seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data exist. Our approach should inform the design of new seed mixes to ensure continuity in floral resource availability throughout the year, and to identify suitable species to fill resource gaps in established mixes