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[en] Full text: Japanese embrittlement trend curve (ETC) of neutron irradiated reactor pressure vessel (RPV) steel is defined in Japan Electric Association Code (JEAC) 4201. The current version of JEAC 4201, JEAC 4201-2013, first calculates the microstructural formation by neutron irradiation, which is then used to predict the mechanical property change in terms of transition temperature shift. In order to improve the prediction capability of the Japanese ETC we have revisited the modelling of microstructural formation through a very detailed investigation of the Atom Probe Tomography data of the Japanese surveillance materials, and then tried to improve the prediction of the amount of embrittlement. In this paper, we report the current status of the activity to develop the modified ETC in Japan. (author)
[en] In addition to EDF contributions to the Technical Working Group on Life Management of NPP (TWG-LM NP), the nuclear engineering division benefits from a complementary multidisciplinary research program devoted to vibration risk of steam generators tubes. The R&D Division carries on this 10-years program which is labeled Qual-IFS-GV. The aim of this communication is to describe the main results of the first six years of the program and to present the planned activities for the next four. Qual-IFS-GV was started focusing on the vibration risk associated with the tube bundle. Even if the perimeter was further extended, tubes vibration-related topics remain the main subject of the program. Four disciplinary departments of the R&D division contribute to the activities which include: thermal hydraulics analysis of the SG, prediction of tubes vibration, fatigue analysis, wear prediction, deposition mechanisms on the shell-side. These contribution will be detailed in the paper. (author)
[en] In recent years, annual electricity consumption in France amounted to around 470 TWh, 90% being decarbonized; at the same time, oil and natural gas consumption has been around 900 TWh and 450 TWh respectively. At present, electricity accounts for only a quarter of energy consumption. Energy savings alone will not be enough to move away from oil and natural gas: as equally anticipated for Germany and Great Britain, French reliance on electricity will have to increase significantly to replace oil and gas consumption. Various recent projections underestimate this growth. However, erroneous assumptions would affect the security of our energy supply and the daily life of the French people; the impacts on the cost of electricity and energy in general, and on the competitiveness of our economy would be considerable. In this position paper, the National Academy of Technologies of France (NATF) proposes a reasonable assessment of electricity demand in 2050. It points out that the European electricity system will be more vulnerable in coming years. It proposes some principles for the choice of economic data to be used in optimisation models. On the basis of these elements, it highlights some key points for managing change in the electricity system.
[fr]La consommation annuelle d'electricite en France a ete d'environ 470 TWh, decarbonee a plus de 90%; dans le meme temps, les consommations de petrole et de gaz naturel ont ete respectivement d'environ 900 TWh et 450 TWh. L'electricite ne represente aujourd'hui que le quart de la consommation d'energie. Les seules economies d'energie ne suffiront pas a sortir du petrole et du gaz naturel: comme le prevoient egalement l'Allemagne et la Grande-Bretagne, le recours a l'electricite en France devra croitre significativement pour se substituer aux consommations de petrole et de gaz. Diverses estimations recentes sous-estiment cette croissance. Or des anticipations erronees affecteraient la securite de notre approvisionnement energetique et la vie quotidienne des francais; les impacts sur le cout de l'electricite et des energies en general, et sur la competitivite de notre economie seraient majeurs. Dans cet avis, l'Academie des technologies propose une evaluation raisonnable de la demande d'electricite en 2050. Elle rappelle que le systeme electrique europeen sera plus fragile dans les prochaines annees. Elle propose quelques principes pour le choix des donnees economiques a retenir dans les optimisations. A partir de ces elements, elle souligne quelques points clefs de la conduite du changement du systeme electrique.
[en] Recently, Fe-based superconductors have shown promising properties of high critical temperature and high upper critical fields, which are prerequisites for applications in high-field magnets. Critical temperature, T, is an important characteristic correlated with crystallographic and electronic structures. By doping with foreign ions in the crystal structure, T can be modified, which however requires significant manpower and resources for materials synthesis and characterizations. In this study, we develop the Gaussian process regression model to predict T of doped Fe-based superconductors based on structural and topological parameters, including the lattice constants, volume, and bonding parameter topological index H. The model is stable and accurate, contributing to fast T estimations.
[en] The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture launched a new Coordinated Research Project (D1.50.19) called “Monitoring and Predicting Radionuclide Uptake and Dynamics for Optimizing Remediation of Radioactive Contamination in Agriculture'', in October 2019. Within the CRP, the high-throughput characterization of soil properties and the estimation of soil-to-plant transfer factors of radionuclides are of critical importance. As already highlighted in Soils Newsletter Vol. 43, No. 1, July 2020, for several decades, soil researchers have been successfully using near and mid-infrared spectroscopy (MIRS) techniques to estimate a wide range of soil properties (Carbon, Nitrogen, CEC, Clay, Sand, pH, ...). In recent years, soil science researchers are increasingly shifting their focus from traditional modeling techniques such as PLSR (Partial Least Squares Regression) to new classes of algorithms, such as Ensemble Learning (Random Forest, Boosting, …) or Deep Learning (Convolutional Neural Networks), that have proven to outperform PLSR on most (if not all) soil properties prediction in a large data regime.
[en] Our yearly Joint FAO/IAEA Division staff training at Seibersdorf, funded by the FAO Headquarters in Rome, was organized from 12-16 October 2020 by the SWMCNL. This time the staff training was about the theoretical and practical principles of mathematical processing of (mid-infrared) spectral datasets for the prediction of characteristics of soils, plants, food or insects. The focus of the training was on the use of traditional partial least squares regression and advanced machine learning approaches, with case studies in Python or similar open-source data analysis toolboxes.
[en] Full text: SOTERIA, “Safe long term operation of light water reactors based on improved understanding of radiation effects”, is a project partly funded by the European Commission as part of the EU framework programm for Research and Innovation “Horizon 2020”. SOTERIA started in September 2015 and gathers together 24 European research centers and industrial partners from 11 different countries. The project will run until 2019 under the coordination of CEA. SOTERIA proposes a comprehensive research approach in order to achieve these ambitions by enabling nuclear power plant operators, as well as regulators, to better understand and thereby predict the ageing phenomena occurring in reactor pressure vessels and internal steels in order to ensure a safe long-term operation of existing European nuclear power plants. SOTERIA will provide further knowledge and tools to manage the ageing of nuclear power plants by addressing 4 specific technical objectives: 1- Carry out experiments assessing neutron flux and fluence effects on reactor pressure vessels and internal steels in pressurised water reactors. 2- Evaluate the residual lifetime of reactor pressure vessels by taking into account metallurgical heterogeneities. 3- Assess the effect of the chemical and radiation environment on embrittlement in internals. 4- Develop models for the assessment of ageing mechanisms in RPV and internals and set of an integrated computer-based platform including the new modelling tools. Models considered in this SOTERIA are: • Nanofeature models to better simulate the evolution due to irradiation in both RPV steels and internals. • Mechanical models to better simulate hardening & embrittlement for RPV steels, hardening and swelling for internals structures. • Mechanical models specific to fracture behaviour • IASCC models or models taking into account chemical and environmental aspects Modelling tools are integrated in a computer-based platform including a chain of modules grouping different models for different parameters to be taken into account in the life-time assessment. A lot of work has been done in the previous FP6 PERFECT and FP7 PERFORM 60 projects concerning the development of a numerical platform. With respect to the existing PERFORM 60 platform, SOTERIA develop tools available as independent modules so that it could be possible to obtain answers to the different industrial key questions (for example the prediction of the ductile to brittle transition temperature or the prediction of the irradiated microstructure). Assessment of modelling tools will be carried out on industrial cases. In this presentation we will present the interface of the platform through case studies assessing the ageing of NPP components subjected to irradiation. (author)
[en] Lumbar spine MRI interpretations have high variability reducing utility for surgical planning. This study evaluated a convolutional neural network (CNN) framework that generates automated MRI grading for its ability to predict the level that was surgically decompressed. Patients who had single-level decompression were retrospectively evaluated. Sagittal T2 images were processed by a CNN (SpineNet), which provided grading for the following: central canal stenosis, disc narrowing, disc degeneration, spondylolisthesis, upper/lower endplate morphologic changes, and upper/lower marrow changes. The grades were used to calculate an aggregate score. The variables and the aggregate score were analyzed for their ability to predict the surgical level. For each surgical level subgroup, the surgical level aggregate scores were compared with the non-surgical levels. A total of 141 patients met the inclusion criteria (82 women, 59 men; mean age 64 years; age range 28–89 years). SpineNet did not identify central canal stenosis in 32 patients. Of the remaining 109, 96 (88%) patients had a decompression at the level of greatest stenosis. The higher stenotic grade was present only at the surgical level in 82/96 (85%) patients. The level with the highest aggregate score matched the surgical level in 103/141 (73%) patients and was unique to the surgical level in 91/103 (88%) patients. Overall, the highest aggregate score identified the surgical level in 91/141 (65%) patients. The aggregate MRI score mean was significantly higher for the L3-S1 surgical levels. A previously developed CNN framework accurately predicts the level of microdecompression for degenerative spinal stenosis in most patients.
[en] We used an ultrasound-enhanced scintillation proximity assay to accurately determine the levels of complement decay-accelerating factor (CD55) for the early detection and assessment of the progression of pleural metastatic lung cancer. We found that the expression of CD55 in metastatic tumor tissues is 2.8 times higher than that in the serum at the early stages. We also found that the concentration of CD55 in serum decreases with the progression of metastasis. These results suggest that CD55 is a potential biomarker for the prediction of pleural metastatic lung cancer. (author)
[en] The author proposes an assessment of the environmental print of our energy future and thus of the expected benefits of energy transition, by using a life cycle analysis as a tool. For example, he reports the analysis of the evolution of the environmental performance of the photovoltaic sector, of the whole Danish wind energy fleet, of the self-consumption of renewable energies, or the assessment of energy scenarios by 2030 at the scale of an insular territory (the Reunion Island). Thus, after a brief overview of environmental impacts of energy, and a presentation of the adopted method, the author addresses the assessment of the environmental performance of energy production: development of models for wind energy, photovoltaic energy, hydroelectric energy, thermal plants, use of these models to represent the technological, space and time variability of these systems, multi-criterion comparison of the environmental impacts of the different energy production sectors. Based on the use of the same approach, the author then presents results related to different energy storage sectors (power-to-hydrogen, power-to-methane, pump storage power stations, compressed air, electrochemical batteries), and a multi-criterion comparison. Based on the previous results, the author addresses environmental impacts of renewable energies in the case of self-consumption by using two scenarios (wind energy with a long-term or seasonal storage, photovoltaic production with a short-term or daily storage). The last chapter reports the application of the method to the case of the Reunion Island