Tritium supply and use: a key issue for the development of nuclear fusion energy

Full power operation of the International Thermonuclear Experimental Reactor (ITER) has been delayed and will now begin in 2035. Delays to the ITER schedule may affect the availability of tritium for subsequent fusion devices, as the global CANDU-type fission reactor fleet begins to phase out over the coming decades. This study provides an up to date account of future tritium availability by incorporating recent uncertainties over the life extension of the global CANDU fleet, as well as considering the potential impact of tritium demand by other fusion efforts. Despite the delays, our projections suggest that CANDU tritium remains sufficient to support the full operation of ITER. However, whether there is tritium available for a DEMO reactor following ITER is largely uncertain, and is subject to numerous uncontrollable externalities. Further tritium demand may come from any number of private sector “compact fusion” start-ups which have emerged in recent years, all of which aim to accelerate the development of fusion energy. If the associated technical challenges can be overcome, compact fusion programmes have the opportunity to use tritium over the next two decades whilst it is readily available, and before full power DT operation on ITER starts in 2035. Assuming a similar level of performance is achievable, a compact fusion development programme, using smaller reactors operating at lower fusion power, would require smaller quantities of tritium than the ITER programme, leaving sufficient tritium available for multiple concepts to be developed concurrently. The development of concurrent fusion concepts increases the chances of success, as it spreads the risk of failure. Additionally, if full tritium breeding capability is not expected to be demonstrated in DEMO until after 2050, an opportunity exists for compact fusion programmes to incorporate tritium breeding technology in nearer-term devices. DD start-up, which avoids the need for external tritium for reactor start-up, is dependent upon full tritium breeding capability, and may be essential for large-scale commercial roll-out of fusion energy. As such, from the standpoint of availability and use of external tritium, a compact route to fusion energy may be more advantageous, as it avoids longer-term complications and uncertainties in the future supply of tritium

Nuclear Physics for Cultural Heritage

Nuclear physics applications in medicine and energy are well known and widely reported. Less well known are the many important nuclear and related techniques used for the study, characterization, assessment and preservation of cultural heritage. There has been enormous progress in this field in recent years and the current review aims to provide the public with a popular and accessible account of this work. The Nuclear Physics Division of the EPS represents scientists from all branches of nuclear physics across Europe. One of its aims is the dissemination of knowledge about nuclear physics and its applications. This review is led by Division board member Anna Macková, Head of the Tandetron Laboratory at the Nuclear Physics Institute of the Czech Academy of Sciences, and the review committee includes four other members of the nuclear physics board interested in this area: Faiçal Azaiez, Johan Nyberg, Eli Piasetzky and Douglas MacGregor. To create a truly authoritative account, the Scientific Editors have invited contributions from leading experts across Europe, and this publication is the combined result of their work. The review is extensively illustrated with important discoveries and examples from archaeology, pre-history, history, geography, culture, religion and curation, which underline the breadth and importance of this field. The large number of groups and laboratories working in the study and preservation of cultural heritage across Europe indicate the enormous effort and importance attached by society to this activity

Towards Resilience to Nuclear Accidents:Financing Nuclear Liabilities via Catastrophe Risk Bonds

In light of the 2011 Fukushima disaster, recent discussion has focused on finding the best nuclear storage options, maximizing the oversight power of global institutions, and strengthening safety measures. In addition to these, the development of dependable liability coverage that can be tapped in an emergency is also needed and should be considered thoughtfully. To succeed, financing is essential using special-purpose instruments from the global bond market, which is as big as US$175 trillion. Thus, in this paper, for the first time, a two-coverage-type trigger nuclear catastrophe (N-CAT) risk bond for potentially supplementing the covering of U.S. commercial nuclear power plants (NPPs) beyond the coverage per the Price Anderson Act as amended, and potentially other plants are proposed and designed worldwide. The N-CAT peril is categorized by three risk layers: incident, accident, and major accident. The pricing formula is derived by using a semi-Markovian dependence structure in continuous time. A numerical application illustrates the main findings of the paper.</jats:p

Nuclear electromagnetic dipole response with the Self-Consistent Green's Function formalism

Microscopic calculations of the electromagnetic response of medium-mass nuclei are now feasible thanks to the availability of realistic nuclear interactions with accurate saturation and spectroscopic properties, and the development of large-scale computing methods for many-body physics. The purpose is to compute isovector dipole electromagnetic (E1) response and related quantities, i.e. integrated dipole cross section and polarizability, and compare with data from photoabsorption and Coulomb excitation experiments. The single-particle propagator is obtained by solving the Dyson equation, where the self-energy includes correlations non-perturbatively through the Algebraic Diagrammatic Construction (ADC) method. The particle-hole ($ph$) polarization propagator is treated in the Dressed Random Phase Approximation (DRPA), based on an effective correlated propagator that includes some $2p2h$ effects but keeps the same computation scaling as the standard Hartree-Fock propagator. The E1 responses for $^{14,16,22,24}$O, $^{36,40,48,52,54,70}$Ca and $^{68}$Ni have been computed: the presence of a soft dipole mode of excitation for neutron-rich nuclei is found, and there is a fair reproduction of the low-energy part of the experimental excitation spectrum. This is reflected in a good agreement with the empirical dipole polarizability values. For a realistic interaction with an accurate reproduction of masses and radii up to medium-mass nuclei, the Self-Consistent Green's Function method provides a good description of the E1 response, especially in the part of the excitation spectrum below the Giant Dipole Resonance. The dipole polarizability is largely independent from the strategy of mapping the dressed propagator to a simplified one that is computationally manageableComment: 14 pages, 12 figure

Nuclear Matter and Nuclear Dynamics

Highlights on the recent research activity, carried out by the Italian Community involved in the "Nuclear Matter and Nuclear Dynamics" field, will be presented.Comment: Proceedings of the 12th Conference on Problems in Theoretical Nuclear Physics, to appear in Journal of Physics, Conference Serie

Nuclear Forces and Nuclear Structure

After a historical review, I present the progress in the field of realistic NN potentials that we have seen in recent years. A new generation of very quantitative (high-quality/high-precision) NN potentials has emerged. These potentials will serve as reliable input for microscopic nuclear structure calculations and will allow for a systematic investigation of off-shell effects. The issue of three-nucleon forces is also discussed.Comment: Invited Talk presented at Nuclear Structure '98, Gatlinburg, Tennessee, August 10-15, 1998; 15 pages, 6 figures, aipproc2.sty and epsfig.st

Dark matter assisted Dirac leptogenesis and neutrino mass

We propose a minimal extension of the standard model with U(1)_{B-L} \times Z_{2} symmetry. In this model by assuming that the neutrinos are Dirac (i.e. $B-L$ is an exact symmetry), we found a simultaneous solution for non zero neutrino masses and dark matter content of the universe. The observed baryon asymmetry of the universe is also explained using Dirac Leptogenesis, which is assisted by a dark sector, gauged under a U(1)_D symmetry. The latter symmetry of the dark sector is broken at a TeV scale and thereby giving mass to a neutral gauge boson Z_D. The standard model Z-boson mixes with the gauge boson Z_D at one loop level and thus paves a way to detect the dark matter through spin independent elastic scattering at terrestrial laboratories.Comment: 12 pages, 10 figures. Accepted for publication in Nuclear Physics

Nuclear deficit : why nuclear weapons are natural, but Scotland doesn’t need nature

This article argues that millennial Scottish culture has been animated in large part by a push to overcome a historiographical compulsion built into the modern British state’s understanding of nature. This understanding of nature became the foundational principle of government during the Financial Revolution and British unification in the 1690s−1710, then was made the subject of a universal history by the Scottish Enlightenment of the later eighteenth century, and has remained in place to be extended by neoliberalism. The article argues more specifically that the British association of progress with dominion over the world as nature demands a temporal abstraction, or automation, reducing the determinability of the present, and that correspondingly this idea of nature ‘softens’ conflict in a way that points to weapons carrying perfectly abstracted violence. Nuclear weapons become an inevitable corollary of the nature of British authority. Against this, twenty-first century Scottish cultures, particularly a growing mainstream surrounding independence or stressing national specificity, have noticeably turned against both nuclear weapons and the understanding of nature these weapons protect. These cultures draw from a 1980s moment in which anti-nuclear action came both to be understood as ‘national’, and to stand in relief to the British liberal firmament. These cultures are ‘activist’ in the literal sense that they tend to interrupt an assumption of the eternal that stands behind both nuclear terror and its capture of nature as dominion over the world. A dual interruption, nuclear and counter-natural, can be read in pro-independence cultural projects including online projects like Bella Caledonia and National Collective, which might be described as undertaking a thorough ‘denaturing’. But if the question of nature as resources for dominion has been a topic for debate in the environmental humanities, little attention has been paid to this specifically British ‘worlding’ of nature, or to how later constitutional pressures on the UK also mean pressures on this worlding. Andreas Malm’s Fossil Capital (2016), for example, a powerful account of the automation of production in the British industrial revolution, might be related to the automation of ideas of progress pressed during the Scottish Enlightenment, and entrenching a dualism of owning subject and nature as object-world that would drive extraction in empire. Finally, this article suggests that this dualism, and the nature holding it in place, have also been a major target of the ‘wilderness encounters’ that form a large sub-genre in twenty-first century Scottish writing. Such ‘denaturing’ encounters can be read in writers like Alec Finlay, Linda Cracknell, Thomas A. Clark, and Gerry Loose, often disrupting the subject standing over nature, and sometimes explicitly linking this to a disruption of nuclear realism