441 research outputs found

    AN EVALUATION OF THE SUBSTITUTION OF ZIRCALOY FOR STAINLESS STEEL IN N.S. SAVANNAH FUEL-ELEMENT CONTAINERS. Summary Report

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    The possibility of reducing fuel-cycle costs for the N.S. SAVANNAH by replacing the stainless steel fuelelement containers in the permanent reactor core structure by similar containers of a zirconium alloy was investigated. These containers, although not integral parts of the fuel-bearing components, are located within the active core and divide the core into 32 separate channels into which the fuel elements are placed. Areas of investigation included reactor physics, fuel-cycle economics, materials compatibility, structural design, and reactor hazards. A summary of the method of analysis and results is given for each area ot investigation. Calculations indicated that the substitution of Zircaloy containers would increase core reactivity about 6% DELTA k and control- rod worth about 4% DELTA k. Fuel-cycle costs would be reduced about 26%. Zircaloy-4 appears to be compatible with the reactor system, except for some uncertainty with respect to fretting corrosion, which can be resolved only by tests. The substitution of cold-worked Zircaloy for stainless steel in the container assembly would necessitate only minor design modifications. Although this evaluation is strictly applicable only to the N.S. SAVANNAH reactor, the results demonstrate the feasibility and advantages of using zirconium alloys for in-core capital-cost components. (auth

    Building a Social Mandate for Climate Action: Lessons from COVID-19

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    The COVID-19 imposed lockdown has led to a number of temporary environmental side effects (reduced global emissions, cleaner air, less noise), that the climate community has aspired to achieve over a number of decades. However, these benefits have been achieved at a massive cost to welfare and the economy. This commentary draws lessons from the COVID-19 crisis for climate change. It discusses whether there are more sustainable ways of achieving these benefits, as part of a more desirable, low carbon resilient future, in a more planned, inclusive and less disruptive way. In order to achieve this, we argue for a clearer social contract between citizens and the state. We discuss how COVID-19 has demonstrated that behaviours can change abruptly, that these changes come at a cost, that we need a ‘social mandate’ to ensure these changes remain in the long-term, and that science plays an important role in informing this process. We suggest that deliberative engagement mechanisms, such as citizens’ assemblies and juries, could be a powerful way to build a social mandate for climate action post-COVID-19. This would enable behaviour changes to become more accepted, embedded and bearable in the long-term and provide the basis for future climate action

    Rift structure and sediment infill of hyperextended continental crust: insights from 3D seismic and well data (Xisha Trough, South China Sea)

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    Three‐dimensional seismic and well data from the deepwater Xisha Trough are used to investigate the rift structure and sediment infill of a region formed adjacently to the initial oceanic ridge of the South China Sea (SCS). The high‐quality data permitted a detailed analysis of features such as: (1) detachment faults soling out at the Moho, (2) rotated and thinned continental blocks covered by thick sediment, and (3) changes in the location of basin depocenters resulting from detachment faulting. During the continental rifting phase (Eocene to earliest Oligocene), faulting was broadly distributed in Xisha Trough and resulted in the generation of isolated grabens/half‐grabens filled by proximal sediment sources. During continental breakup in the Northwest Ocean Sector of SCS (Oligocene), extension became restricted to a narrow region where highly tilted continental blocks and thin crust were formed. Sediment was, at that time, fed to distal depocenters, which are presently bounded by listric faults rooted in a basal detachment. Later in a second stage (early Miocene), synchronously with continental breakup in the Southwest Ocean Sector of the SCS, the study area was blanketed by thick sediment. During the two continental breakup events, the hyperextended Xisha Trough was affected by closely spaced, small‐scale faults rather than large basement‐related structures. Our study highlights the effect of continental breakup as a way to broaden sediment influx from multiple sources into deepwater basins. As a corollary, this work recognizes two distinct breakup sequences in the Xisha Trough, and concludes on their geodynamic significance to the SCS

    Prospects for radical emissions reduction through behaviour and lifestyle change

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    Over the past two decades, scholars and practitioners across the social sciences, in policy and beyond have proposed, trialled and developed a wide range of theoretical and practical approaches designed to bring about changes in behaviours and lifestyles that contribute to climate change. With the exception of the establishment of a small number of iconic behaviours such as recycling, it has however proved extremely difficult to bring about meaningful transformations in personal greenhouse gas emissions at either the individual or societal level, with multiple reviews now pointing to the limited efficacy of current approaches. We argue that the majority of approaches designed to achieve mitigation have been constrained by the need to operate within prevailing social scientific, economic and political orthodoxies which have precluded the possibility of non-marginal change. In this paper we ask what a truly radical approach to reducing personal emissions would look like from social science perspectives which challenge the unstated assumptions severely limiting action to date, and which explore new alternatives for change. We emphasise the difficulties likely to impede the instituting of genuinely radical societal change regarding climate change mitigation, whilst proposing ways that the ground could be prepared for such a transformation to take place

    The impact of COVID-19 related regulations and restrictions on mobility and potential for sustained climate mitigation across the Netherlands, Sweden and the UK: a data-based commentary

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    Human behaviour change is necessary to meet targets set by the Paris Agreement to mitigate climate change. Restrictions and regulations put in place globally to mitigate the spread of COVID-19 during 2020 have had a substantial impact on everyday life, including many carbon-intensive behaviours such as transportation. Changes to transportation behaviour may reduce carbon emissions. Behaviour change theory can offer perspective on the drivers and influences of behaviour and shape recommendations for how policy-makers can capitalise on any observed behaviour changes that may mitigate climate change. For this commentary, we aimed to describe changes in data relating to transportation behaviours concerning working from home during the COVID-19 pandemic across the Netherlands, Sweden and the UK. We display these identified changes in a concept map, suggesting links between the changes in behaviour and levels of carbon emissions. We consider these changes in relation to a comprehensive and easy to understand model of behaviour, the Opportunity, Motivation Behaviour (COM-B) model, to understand the capabilities, opportunities and behaviours related to the observed behaviour changes and potential policy to mitigate climate change. There is now an opportunity for policy-makers to increase the likelihood of maintaining pro-environmental behaviour changes by providing opportunities, improving capabilities and maintaining motivation for these behaviours

    From ‘greenest government ever’ to ‘get rid of all the green crap’: David Cameron, the Conservatives and the environment

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    The environment was David Cameron’s signature issue underpinning his modernization agenda. In opposition the ‘Vote Blue, Go Green’ strategy had a positive impact on the party’s image: the environment operated as a valence issue in a period of raised public concern, particularly about climate change, and Cameron’s high-profile support contributed to the cross-party consensus that delivered radical change in climate policy. Although the Coalition government has implemented important environmental measures, the Conservatives have not enhanced their green credentials in government and Cameron has failed to provide strong leadership on the issue. Since 2010, climate change has to some extent been transformed into a positional issue. Conservative MPs, urged on by the right-wing press, have adopted an increasingly partisan approach to climate change, and opinion polls reveal clear partisan divisions on climate change amongst public opinion. As a positional issue climate change has become challenging for the Conservatives, showing them to be internally divided, rebellious and inclined to support producer interests. This article makes a contribution to our understanding of Conservative modernization, while also challenging the dominant assumption in the scholarly literature that the environment, particularly climate change, is a valence issue

    Global and local concerns: What attitudes and beliefs motivate farmers to mitigate and adapt to climate change?

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    In response to agriculture\u27s vulnerability and contribution to climate change, many governments are developing initiatives that promote the adoption of mitigation and adaptation practices among farmers. Since most climate policies affecting agriculture rely on voluntary efforts by individual farmers, success requires a sound understanding of the factors that motivate farmers to change practices. Recent evidence suggests that past experience with the effects of climate change and the psychological distance associated with people\u27s concern for global and local impacts can influence environmental behavior. Here we surveyed farmers in a representative rural county in California\u27s Central Valley to examine how their intention to adopt mitigation and adaptation practices is influenced by previous climate experiences and their global and local concerns about climate change. Perceived changes in water availability had significant effects on farmers\u27 intention to adopt mitigation and adaptation strategies, which were mediated through global and local concerns respectively. This suggests that mitigation is largely motivated by psychologically distant concerns and beliefs about climate change, while adaptation is driven by psychologically proximate concerns for local impacts. This match between attitudes and behaviors according to the psychological distance at which they are cognitively construed indicates that policy and outreach initiatives may benefit by framing climate impacts and behavioral goals concordantly; either in a global context for mitigation or a local context for adaptation
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