Defence in depth (DiD) is a concept that has been used for many years alongside tools to optimise nuclear safety in reactor design, assessment and regulation. The 2011 Fukushima Daiichi nuclear power ...plant accident provided unique insight into nuclear safety issues and raised questions about the tools used at nuclear power plants, including the effectiveness of the DiD concept, and whether DiD can be enhanced and its implementation improved. This report is intended primarily for nuclear regulatory bodies, although information included herein is expected to be of interest to licensees, nuclear industry organisations and the general public.
Countries around the world continue to implement safety improvements and corrective actions based on lessons learnt from the 11 March 2011 accident at the Fukushima Daiichi nuclear power plant. This ...report provides a high-level summary and update on these activities, and outlines further lessons learnt and challenges identified for future consideration. It focuses on actions taken by NEA committees and NEA member countries, and as such is complementary to reports produced by other international organisations.
Possible enhancement of ionospheric Total Electron Content (TEC) immediately before the 2011 Tohoku‐oki earthquake (Mw9.0) has been reported by Heki (2011). Critical responses to it often come in two ...stages; they first doubt the enhancement itself and attribute it to an artifact. Second (when they accept the enhancement), they doubt the significance of the enhancement among natural variability of space weather origin. For example, Kamogawa and Kakinami (2013) attributed the enhancement to an artifact falsely detected by the combined effect of the highly variable TEC under active geomagnetic condition and the occurrence of a tsunamigenic ionospheric hole. Here we closely examine the time series of vertical TEC before and after the 2011 Tohoku‐oki earthquake. We first demonstrate that the tsunami did not make an ionospheric hole, and next confirm the reality of the enhancement using data of two other sensors, ionosonde and magnetometers. The amplitude of the preseismic TEC enhancement is within the natural variability, and its snapshot resembles to large‐scale traveling ionospheric disturbances. However, distinction could be made by examining their propagation properties. Similar TEC anomalies occurred before all the M ≥ 8.5 earthquakes in this century, suggesting their seismic origin.
Key Points
Tsunami does not make an ionpsheric hole
TEC enhancement, changes in foEs and declination started together
All earthquakes exceeding M8.5 are preceded by TEC enhancements
The U.S. Congress asked the National Academy of Sciences to conduct a technical study on lessons learned from the Fukushima Daiichi nuclear accident for improving safety and security of commercial ...nuclear power plants in the United States. This study was carried out in two phases: Phase 1, issued in 2014, focused on the causes of the Fukushima Daiichi accident and safety-related lessons learned for improving nuclear plant systems, operations, and regulations exclusive of spent fuel storage. This Phase 2 report focuses on three issues: (1) lessons learned from the accident for nuclear plant security, (2) lessons learned for spent fuel storage, and (3) reevaluation of conclusions from previous Academies studies on spent fuel storage.
La tomographie par émission monophotonique (TEMP) est utilisée pour diagnostiquer et surveiller le système squelettique. Cependant, en raison de l’activité injectée, son utilisation est liée à une ...augmentation de l’exposition au rayonnement du patient.
Estimer la dose de rayonnement reçue par les patients lors d’une scintigraphie osseuse et établir leur niveau de référence diagnostique local (NRD).
Dans cette étude princeps prospective réalisée de septembre à novembre 2023, les données de 87 patients ayant subi une scintigraphie osseuse ont été collectées. Le NRD a été déterminé en fonction du 75e centile de la distribution de 99mTc-HMDP administrés, selon les recommandations de la Commission Internationale de Protection Radiologique (CIPR). La dose efficace a été calculée en utilisant le logiciel MIRDcalc v1.2.
L’âge moyen des patients était 55 ans. Ces patients ont reçu une activité d’injection d’environ 874,6 MBq de 99mTc-HMDP correspondant au NRD, ce qui a donné une dose efficace de 3,30 mSv. Le NRD proposé et la dose efficace pour l’acquisition respectaient les normes internationales.
Cette étude présente le processus de mise en œuvre et les résultats du premier NRD national pour la Médecine Nucléaire en Côte d’Ivoire comme moyen d’optimisation de l’exposition aux rayonnements.
Why are the east sides of formerly industrial cities more deprived? To answer this question, we use individual-level census data and create historical pollution patterns derived from the locations of ...5,000 industrial chimneys and an atmospheric model. We show that this observation results from path-dependent neighborhood sorting that began during the Industrial Revolution, as prevailing winds blew pollution eastward. Past pollution explains up to 20% of observed neighborhood segregation in 2011, even though coal pollution stopped in the 1970s. We develop a quantitative model to identify the role of neighborhood effects and relocation rigidities underlying this persistence.
Subduction zone plate boundary megathrust faults accommodate relative plate motions with spatially varying sliding behavior. The 2004 Sumatra‐Andaman (Mw 9.2), 2010 Chile (Mw 8.8), and 2011 Tohoku ...(Mw9.0) great earthquakes had similar depth variations in seismic wave radiation across their wide rupture zones – coherent teleseismic short‐period radiation preferentially emanated from the deeper portion of the megathrusts whereas the largest fault displacements occurred at shallower depths but produced relatively little coherent short‐period radiation. We represent these and other depth‐varying seismic characteristics with four distinct failure domains extending along the megathrust from the trench to the downdip edge of the seismogenic zone. We designate the portion of the megathrust less than 15 km below the ocean surface as domain A, the region of tsunami earthquakes. From 15 to ∼35 km deep, large earthquake displacements occur over large‐scale regions with only modest coherent short‐period radiation, in what we designate as domain B. Rupture of smaller isolated megathrust patches dominate in domain C, which extends from ∼35 to 55 km deep. These isolated patches produce bursts of coherent short‐period energy both in great ruptures and in smaller, sometimes repeating, moderate‐size events. For the 2011 Tohoku earthquake, the sites of coherent teleseismic short‐period radiation are close to areas where local strong ground motions originated. Domain D, found at depths of 30–45 km in subduction zones where relatively young oceanic lithosphere is being underthrust with shallow plate dip, is represented by the occurrence of low‐frequency earthquakes, seismic tremor, and slow slip events in a transition zone to stable sliding or ductile flow below the seismogenic zone.
Key Points
Seismic radiation from megathrust earthquake rupture varies with depth
A 4‐domain model of radiation segmentation is introduced for megathrusts
Strong‐ground motions originate from the down‐dip region
The postseismic Global Navigation Satellite System (GNSS) time series after the 2011 Tohoku‐oki earthquake is often empirically explained by one or more logarithmic and exponential decay functions. ...However, a function model with these decay functions struggles to illuminate various deformation mechanisms. Here, we propose a new function model incorporating laboratory‐derived constitutive laws (power‐law flow and velocity‐strengthening friction) utilized in mechanical postseismic models of the last decade. We demonstrated that our function model accurately predicts the decade‐long time series of inland GNSS stations, including coastal areas where significant postseismic uplift continues now. Moreover, it decomposes them into displacements due to viscoelastic relaxation and afterslip, similar to results produced by previous stress‐dependent postseismic models of the 2011 Tohoku‐oki earthquake. This physics‐based function model is an effective tool to ease the process of forecasting long‐term GNSS time series by dividing them into two dominant mechanisms at the plate interface and the surrounding viscoelastic mantle.
Plain Language Summary
Functional modeling is a standard tool to fit and predict the time series of surface displacements by geodetic observations. Previous studies used single or several logarithmic and exponential functions to fit the geodetic time series following the 2011 Tohoku‐oki earthquake. Although these functions work well in fitting the time series, they hardly explain the various elementary processes contributing to the displacement time series. Here, we developed an alternative function model that mimics ground motion after the Tohoku‐oki earthquake. The model includes postseismic slip on the megathrust interface (afterslip) and flow movement of the surrounding mantle (viscoelastic relaxation). The model uses mathematical expressions that are based on the slip and flow behaviors of rocks in laboratory experiments. The newly proposed model predicts the 10‐year time series accurately. Moreover, it breaks them down into viscoelastic relaxation and afterslip contributions. The space‐time patterns of these two components are similar to the results of the previous postseismic deformation models of the 2011 Tohoku‐oki earthquake. Our functional model can help forecast future ground motions and understand the deformation mechanisms related to megathrust earthquakes.
Key Points
Proposing a function model based on power‐law creep and rate‐strengthening frictional slip
Prediction of decadal Global Navigation Satellite System (GNSS) time series of the 2011 Tohoku‐oki earthquake
Decomposition of postseismic GNSS time series into the displacement due to viscoelastic relaxation and afterslip
To contribute to tsunami early warning systems, we investigated the currently achievable speed of tsunami inundation simulations on a parallel computer as well as the benefits of high‐resolution and ...faster than real‐time inundation predictions. We found that a 5 m resolution inundation simulation can be 75 times faster than real time, requiring only 1.5 min to overview the inundation situation in Sendai City for the 2011 Tohoku tsunami. We developed a novel parallel tsunami model based on the well‐known TUNAMI‐N2 model and achieved 9.17 tera Floating‐point Operations Per Second (FLOPS) on 9469 CPU cores. The present model can accurately hindcast the observed inundated regions of the 2011 Tohoku tsunami using tsunami source estimations of the tFISH and tFISH/RAPiD algorithms, which can be instantly derived from real‐time observation data. The present high‐resolution predictions can provide clear images of imminent hazards/disasters and can provide guidance for appropriate evacuation actions.
Key Points
Five‐meter‐resolution inundation forecasting is 75 times faster than real time
Inundation of the 2011 Tohoku tsunami is reproduced within 1.5 min
High‐resolution prediction provides well‐localized hazard information
From ISIS propaganda videos to popular regime-backed TV series and digital activism, the Syrian conflict has been dramatically affected by the production of media, at the same time generating in its ...turn an impressive visual culture. Yet what are the aesthetic, political and material implications of the collusion between the production of this sheer amount of visual media being continuously shared and re-manipulated on the Internet, and the performance of the conflict on the ground? This ethnography uses the Syrian case to reflect more broadly on how the networked age reshapes contemporary warfare and impacts on the enactment of violence through images and on images. In stark contrast to the techno-utopias celebrating digital democracy and participatory cultures, Donatella Della Ratta’s analysis exposes the dark side of online practices, where visual regimes of representation and media production dramatically intertwine with modes of destruction and the performance of violence. Exploring the most socially-mediated conflict of contemporary times, the book offers a fascinating insight into the transformation of warfare and life in the age of the internet.
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