Uranium nitride-silicide advanced nuclear fuel: Higher efficiency and greater safety

The development of new nuclear fuel compositions is being driven by an interest in improving efficiency/lowering cost and increasing safety margins. Nuclear fuel efficiency is in large measure a function of the atomic density of the uranium, that is, the more fissionable uranium available per unit volume the less fuel volume that is required. Proliferation concerns limit the concentration of fissile 235U, and thus attention is directed to higher overall uranium content fuel. Among the options are the high temperature phases U3Si2 and composite UN- U3Si2 where the design would have the more water-stable U3Si2 surround the more soluble, but higher uranium density UN grains. (Uranium metal of course has the highest atomic density, however its low melting point, high degree of swelling under irradiation, and chemical reactivity eliminate it from consideration.) Another advantage of the nitride and silicide phases are their high thermal conductivity, greatly exceeding the current standard UO2 fuel, with the high conductivity potentially allowing the fuel to operate at a higher power density. Please click Additional Files below to see the full abstract

The making of a maritime explorer: the early career of Matthew Flinders

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal for Maritime Research on 09/08/2016, available online: https://www.tandfonline.com/doi/full/10.1080/21533369.2016.1172839This article examines the early career of Matthew Flinders (1774–1814) to determine the ways in which his training as a navigator, hydrographer and cartographer prepared him for undertaking the first circumnavigation of Australia in the Investigator between 1801 and 1803. Two main questions are answered in relation to this theme. First, why was such a young naval officer as Flinders (he was 26) selected to lead such an important voyage of discovery? And, second, in what ways did the choice of Flinders as the commander of the Investigator reflect the training he had received? The article argues that the making of Flinders as a maritime explorer was forged through his successive nautical achievements in the 1790s, partly in relation to William Bligh’s second breadfruit voyage to the Pacific in 1791–1792 and partly in relation to voyages along the coasts of New South Wales and Van Diemen’s Land that Flinders undertook between 1795 and 1800. During that period, Flinders jointly discovered Bass Strait and circumnavigated Van Diemen’s Land: these were the two most significant geographical discoveries in Australia since the era of Captain Cook. The article shows that when he returned from Port Jackson to London in 1800, Flinders was the most experienced candidate with knowledge of Australian waters who was available to lead the Investigator expedition. It also argues that Flinders placed himself in a highly favourable position to be selected as the leader of the circumnavigation through demonstrating to Sir Joseph Banks, his patron, that he had a thorough, up-to-date knowledge of what needed to be discovered about Australia through maritime exploration. Throughout, there will be an emphasis on the nautical skills Flinders acquired rapidly as a young midshipman and lieutenant and on his determination and initiative to devote his career to Australian discovery.The research was supported by an Australian Bicentennial Fellowship, Menzies Centre for Australian Studies, King’s College, London