17 research outputs found

    Redundancy of Supply in the International Nuclear Fuel Fabrication Market: Are Fabrication Services Assured?

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    For several years, Pacific Northwest National Laboratory (PNNL) has been assessing the reliability of nuclear fuel supply in support of the U.S. Department of Energy/National Nuclear Security Administration. Three international low enriched uranium reserves, which are intended back up the existing and well-functioning nuclear fuel market, are currently moving toward implementation. These backup reserves are intended to provide countries credible assurance that of the uninterrupted supply of nuclear fuel to operate their nuclear power reactors in the event that their primary fuel supply is disrupted, whether for political or other reasons. The efficacy of these backup reserves, however, may be constrained without redundant fabrication services. This report presents the findings of a recent PNNL study that simulated outages of varying durations at specific nuclear fuel fabrication plants. The modeling specifically enabled prediction and visualization of the reactors affected and the degree of fuel delivery delay. The results thus provide insight on the extent of vulnerability to nuclear fuel supply disruption at the level of individual fabrication plants, reactors, and countries. The simulation studies demonstrate that, when a reasonable set of qualification criteria are applied, existing fabrication plants are technically qualified to provide backup fabrication services to the majority of the world's power reactors. The report concludes with an assessment of the redundancy of fuel supply in the nuclear fuel market, and a description of potential extra-market mechanisms to enhance the security of fuel supply in cases where it may be warranted. This report is an assessment of the ability of the existing market to respond to supply disruptions that occur for technical reasons. A forthcoming report will address political disruption scenarios

    Six Years of Chandra Observations of Supernova Remnants

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    We present a review of the first six years of Chandra X-ray Observatory observations of supernova remnants. From the official "first-light" observation of Cassiopeia A that revealed for the first time the compact remnant of the explosion, to the recent million-second spectrally-resolved observation that revealed new details of the stellar composition and dynamics of the original explosion, Chandra observations have provided new insights into the supernova phenomenon. We present an admittedly biased overview of six years of these observations, highlighting new discoveries made possible by Chandra's unique capabilities.Comment: 82 pages, 28 figures, for the book Astrophysics Update

    Proceedings of the Virtual 3rd UK Implementation Science Research Conference : Virtual conference. 16 and 17 July 2020.

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    Offline versus online suicide-related help seeking: changing domains, changing paradigms

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    Objective: Suicidal individuals are among the most reluctant help-seekers, which limits opportunities for treating and preventing unnecessary suffering and self-inflicted deaths. This study aimed to assist outreach, prevention, and treatment efforts by elucidating relationships between suicidality and both online and offline help seeking. Method: An anonymous online survey provided data on 713 participants, aged 18-71 years. Measures included an expanded General Help-Seeking Questionnaire and the Suicidal Affect-Behavior-Cognition Scale. Results: General linear modeling results showed that, as predicted, face-to-face help-seeking willingness decreased as risk level increased. However, for emerging adults help-seeking likelihood increased with informal online sources as risk increased, while other online help-seeking attitudes differed little by risk level. Linear regression modeling determined that, for suicidal individuals, willingness to seek help from online mental health professionals and online professional support sites was strongly related (ps < .001). Help seeking from social networking sites and anonymous online forums was also interrelated, but more complex, demonstrating the importance of age and social support factors (ps < .001). Conclusion: These findings show that the Internet has altered the suicide-related help-seeking paradigm. Online help seeking for suicidality was not more popular than face-to-face help seeking, even for emerging adults. However, treatment and prevention professionals have good reasons to increase their online efforts, because that is where some of the highest risk individuals are going for help with their most severe personal problems

    Evaluation of a Business Case for Safeguards by Design in Nuclear Power Reactors

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    Safeguards by Design (SbD) is a well-known paradigm for consideration and incorporation of safeguards approaches and associated design features early in the nuclear facility development process. This paradigm has been developed as part of the Next Generation Safeguards Initiative (NGSI), and has been accepted as beneficial in many discussions and papers on NGSI or specific technologies under development within NGSI. The Office of Nuclear Safeguards and Security funded the Pacific Northwest National Laboratory to examine the business case justification of SbD for nuclear power reactors. Ultimately, the implementation of SbD will rely on the designers of nuclear facilities. Therefore, it is important to assess the incentives which will lead designers to adopt SbD as a standard practice for nuclear facility design. This report details the extent to which designers will have compelling economic incentives to adopt SbD

    Effects of mexiletine on hyperexcitability in sporadic amyotrophic lateral sclerosis: Preliminary findings from a small phase II randomized controlled trial

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    BackgroundTo collect preliminary data on the effects of mexiletine on cortical and axonal hyperexcitability in sporadic amyotrophic lateral sclerosis (ALS) in a phase 2 double- blind randomized controlled trial.MethodsTwenty ALS subjects were randomized to placebo and mexiletine 300 or 600- mg daily for 4 wk and assessed by transcranial magnetic stimulation and axonal excitability studies. The primary endpoint was change in resting motor threshold (RMT).ResultsRMT was unchanged with 4 wk of mexiletine (combined active therapies) as compared to placebo, which showed a significant increase (P = .039). Reductions of motor evoked potential (MEP) amplitude (P = .013) and accommodation half- time (P = .002), secondary outcome measures of cortical and axonal excitability, respectively, were also evident at 4 wk on mexiletine.ConclusionsThe relative stabilization of RMT in the treated subjects was unexpected and could be attributed to unaccounted sources of error or chance. However, a possible alternative cause is neuromodulation preventing an increase. The change in MEP amplitude and accommodation half- time supports the reduction of cortical and axonal hyperexcitability with mexiletine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/166371/1/mus27146_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/166371/2/mus27146.pd

    Effects of mexiletine on hyperexcitability in sporadic amyotrophic lateral sclerosis: Preliminary findings from a small phase II randomized controlled trial

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    © 2020 Wiley Periodicals LLC Background: To collect preliminary data on the effects of mexiletine on cortical and axonal hyperexcitability in sporadic amyotrophic lateral sclerosis (ALS) in a phase 2 double-blind randomized controlled trial. Methods: Twenty ALS subjects were randomized to placebo and mexiletine 300 or 600 mg daily for 4 wk and assessed by transcranial magnetic stimulation and axonal excitability studies. The primary endpoint was change in resting motor threshold (RMT). Results: RMT was unchanged with 4 wk of mexiletine (combined active therapies) as compared to placebo, which showed a significant increase (P =.039). Reductions of motor evoked potential (MEP) amplitude (P =.013) and accommodation half-time (P =.002), secondary outcome measures of cortical and axonal excitability, respectively, were also evident at 4 wk on mexiletine. Conclusions: The relative stabilization of RMT in the treated subjects was unexpected and could be attributed to unaccounted sources of error or chance. However, a possible alternative cause is neuromodulation preventing an increase. The change in MEP amplitude and accommodation half-time supports the reduction of cortical and axonal hyperexcitability with mexiletine
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