| 1. |
- Cederwall, Bo, 1964-
(författare)
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A novel 3D-imaging and characterisation technique for special nuclear materials in radioactive waste
- 2023
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Ingår i: EPJ NUCLEAR SCIENCES & TECHNOLOGIES. - : EDP Sciences. - 2491-9292. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- A novel technique for non-destructive assay (NDA) of radioactive waste called ARCTERIX (Advanced Radwaste Characterisation based on Tomographically Enhanced Radiation Imaging without X-rays) is presented. The concept is based on a 3D-tomographic imaging technique for special nuclear materials - neutron-gamma emission tomography (NGET). ARCTERIX takes the NGET principle from its original application area of nuclear security systems into the realm of radioactive waste assay with its special characteristics and challenges. By adding localisation and imaging of SNM inside shielded waste containers to the array of existing techniques used for radioactive waste characterisation, ARCTERIX complements the state of the art in passive and active NDA interrogation methods. It is aimed primarily at the class of mixed, long-lived radioactive waste that is commonly called "legacy" or "historic" waste which has special safety, security and safeguards concerns due to its mixed composition, commonly poor documentation, and the frequent presence of SNM. The ARCTERIX concept provides rapid imaging and characterisation of nuclear materials in radioactive waste with a high degree of automation and high throughput capabilities, making it possible to quickly scan large radioactive waste inventories for the presence of special nuclear materials with minimal manual intervention. The first ARCTERIX prototype system has demonstrated a high technological readiness for the implementation of the technique in a commercial stand-alone system for rapid assessment of radioactive waste drums or in a system operating in conjunction with established techniques.
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| 2. |
- Demaziere, Christophe, 1973, et al.
(författare)
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Advanced numerical simulation and modeling for reactor safety - contributions from the CORTEX, McSAFER, and METIS projects
- 2022
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Ingår i: EPJ Nuclear Sciences and Technologies. - : EDP Sciences. - 2491-9292. ; 8
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Forskningsöversikt (refereegranskat)abstract
- This paper gives an account of three projects funded by the European Union that heavily rely on numerical modeling and simulations of nuclear reactors: the CORTEX project (CORe monitoring Techniques and EXperimental validation and demonstration), the McSAFER project (High-Performance Advanced Methods and Experimental Investigations for the Safety Evaluation of Generic Small Modular Reactors), and the METIS project (MEthods and Tools Innovations for Seismic risk assessment). The CORTEX project focuses on neutronic simulations, the McSAFER project considers neutronic, thermalhydraulic, and thermo-mechanic simulations, whereas the METIS project investigates simulations for seismic assessments. Although the projects have different objectives, they present some common features in terms of the complementary modeling approaches used in each project and in terms of verification and validation programs. The main achievements of the projects are presented in the paper covering the technical aspects of the respective projects, training, education, and dissemination activities, as well as utilization and cross-fertilization. All three projects lead to the advancement in nuclear reactor modeling in the above areas, with the development of new simulation capabilities beyond the state-of-the-art.
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| 3. |
- Demaziere, Christophe, 1973, et al.
(författare)
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Advanced numerical simulation and modelling for reactor safety − contributions from the CORTEX, HPMC, McSAFE and NURESAFE projects
- 2020
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Ingår i: EPJ Nuclear Sciences and Technologies. - : EDP Sciences. - 2491-9292. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Predictive modelling capabilities have long represented one of the pillars of reactor safety. In this paper, an account of some projects funded by the European Commission within the seventh Framework Program (HPMC and NURESAFE projects) and Horizon 2020 Program (CORTEX and McSAFE) is given. Such projects aim at, among others, developing improved solution strategies for the modelling of neutronics, thermal-hydraulics, and/or thermo-mechanics during normal operation, reactor transients and/or situations involving stationary perturbations. Although the different projects have different focus areas, they all capitalize on the most recent advancements in deterministic and probabilistic neutron transport, as well as in DNS, LES, CFD and macroscopic thermal-hydraulics modelling. The goal of the simulation strategies is to model complex multi-physics and multi-scale phenomena specific to nuclear reactors. The use of machine learning combined with such advanced simulation tools is also demonstrated to be capable of providing useful information for the detection of anomalies during operation.
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| 4. |
- Ekberg, Christian, 1967, et al.
(författare)
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Fuel fabrication and reprocessing issues: the ASGARD project
- 2020
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Ingår i: EPJ NUCLEAR SCIENCES & TECHNOLOGIES. - : EDP Sciences. - 2491-9292. ; 6
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Forskningsöversikt (refereegranskat)abstract
- The ASGARD project (2012-2016) was designed to tackle the challenge the multi-dimensional questions dealing with the recyclability of novel nuclear fuels. These dimensions are: the scientific achievements, investigating how to increase the industrial applicability of the fabrication of these novel fuels, the bridging of the often separate physics and chemical communities in connection with nuclear fuel cycles and finally to create an ambitious education and training platform. This will be offered to younger scientists and will include a broadening of their experience by international exchange with relevant facilities. At the end of the project 27 papers in peer reviewed journals were published and it is expected that the real number will be the double. The training and integration success was evidenced by the fruitful implementation of the Travel Fund as well as the unique schools, e.g. practical and theoretical handling of plutonium.
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| 5. |
- Lewis, A.M., et al.
(författare)
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Templates of Expected Measurement Uncertainties for Neutron-Induced Capture and Charged-Particle Production Cross Section Observables
- 2023
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Ingår i: EPJ Nuclear Sciences & Technologies. - : EDP Sciences. - 2491-9292. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a template of expected uncertainties and correlations for measurements of neutron-induced capture and charged-particle production cross sections. Measurements performed in-beam include total absorption spectroscopy, total energy detection, γ-ray spectroscopy, and direct charged-particle detection. Offline measurements include activation analysis and accelerator mass spectrometry. The information needed for proper use of the datasets in resonance region and high energy region evaluations is described, and recommended uncertainties are provided when specific values are not available for a dataset.
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| 6. |
- Lewis, Amanda M., et al.
(författare)
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Templates of expected measurement uncertainties for total neutron cross-section observables
- 2023
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Ingår i: EPJ NUCLEAR SCIENCES & TECHNOLOGIES. - : EDP Sciences. - 2491-9292. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a template of expected uncertainties and correlations for measurements of total neutron cross-section observables by transmission. Measurements with time-of-flight and mono-energetic neutron sources are covered. The information required for evaluations in the resonance region and high energy region is detailed, along with the template of uncertainties and correlations that can be used in the absence of other information.
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| 7. |
- Neudecker, Denise, et al.
(författare)
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Templates of expected measurement uncertainties
- 2023
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Ingår i: EPJ NUCLEAR SCIENCES & TECHNOLOGIES. - : EDP Sciences. - 2491-9292. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The covariance committee of CSEWG (Cross Section Evaluation Working Group) established templates of expected measurement uncertainties for neutron-induced total, (n,gamma), neutron-induced charged-particle, and (n,xn) reaction cross sections as well as prompt fission neutron spectra, average prompt and total fission neutron multiplicities, and fission yields. Templates provide a list of what uncertainty sources are expected for each measurement type and observable, and suggest typical ranges of these uncertainties and correlations based on a survey of experimental data, associated literature, and feedback from experimenters. Information needed to faithfully include the experimental data in the nuclear-data evaluation process is also provided. These templates could assist (a) experimenters and EXFOR compilers in delivering more complete uncertainties and measurement information relevant for evaluations of new experimental data, and (b) evaluators in achieving a more comprehensive uncertainty quantification for evaluation purposes. This effort might ultimately lead to more realistic evaluated covariances for nuclear-data applications. In this topical issue, we cover the templates coming out of this CSEWG effort-typically, one observable per paper. This paper here prefaces this topical issue by introducing the concept and mathematical framework of templates, discussing potential use cases, and giving an example of how they can be applied (estimating missing experimental uncertainties of 235U(n,f) average prompt fission neutron multiplicities), and their impact on nuclear-data evaluations.
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| 8. |
- Pavel, Gabriel Lazaro, et al.
(författare)
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Education, training and mobility, knowledge management: towards a common effort to ensure a future workforce in Europe and abroad
- 2023
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Ingår i: EPJ Nuclear Sciences and Technologies. - 2491-9292. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Continuous and future-oriented education and training as well as knowledge management for young talents are required for the safe and reliable operation of nuclear reactors and nuclear facilities in Europe. A dedicated line of collaborative projects addresses the specific needs, such as lack of personnel (project ENEN+: “attract, retain and develop new nuclear talents beyond academic curricula”). State-of-the-art approaches and in-depth knowledge are provided when it comes to reactor physics (project GRE@T-PIONEeR: “graduate education alliance for teaching the physics and safety of nuclear reactors”) or nuclear radiochemistry (project A-CINCH: “augmented cooperation in education and training in nuclear and radiochemistry”). A highly skilled nuclear engineer must undergo experimental work to better observe theoretical principles at work. Following the ENEEP (European nuclear experimental educational platform) initiative, a network of research reactors and special laboratories is made available for performing such activities. Another issue found is that the results of Euratom-funded research activities are spread across multiple platforms and websites making it difficult to find relevant information within a reasonable timeframe. Such a situation requires the application of knowledge management actions. The PIKNUS project aims to define a concept of a knowledge management method and tool to improve the sharing and availability of Euratom research results. All projects successfully demonstrate that European collaboration could address certain needs to attract, develop and retain young talents in future-oriented nuclear fields.
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| 9. |
- Samuelsson, Karl, 1987-, et al.
(författare)
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An improved method to evaluate the "Joint Oxyde-Gaine" formation in (U,Pu)O-2 irradiated fuels using the GERMINAL V2 code coupled to Calphad thermodynamic computations
- 2020
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Ingår i: EPJ NUCLEAR SCIENCES & TECHNOLOGIES. - : EDP Sciences. - 2491-9292. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- In this work, two different thermodynamic softwares, ANGE using the TBASE database, and OPENCALPHAD using the TAF-ID (Thermodynamics of Advanced Fuels - International Database), have been integrated into the GERMINAL V2 fuel performance code (of the PLEIADES platform) in order to evaluate the chemical state of (U, Pu)O-2 fuel and fission products in sodium cooled fast reactors. A model to calculate the composition and the thickness of the "Joint-Oxyde Gaine" (JOG) fission product layer in the fuel-clad gap has been developed. Five fuel pins with a final burnup ranging between 3.8 and 13.4% FIMA (Fissions per Initial Metal Atom) have been simulated, and the calculated width of the fission product layer have been compared with post irradiation examinations. The two different thermodynamic softwares have been compared in terms of computation time and predicted fuel-to-clad gap chemistry. The main elements and phases encountered in the fission productlayer have been identified, and the impact of the changing oxygen potential has been explored.
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| 10. |
- Siefman, Daniel, et al.
(författare)
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Data assimilation of post-irradiation examination data for fission yields from GEF
- 2020
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Ingår i: EPJ NUCLEAR SCIENCES & TECHNOLOGIES. - : EDP SCIENCES S A. - 2491-9292. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear data, especially fission yields, create uncertainties in the predicted concentrations of fission products in spent fuel which can exceed engineering target accuracies. Herein, we present a new framework that extends data assimilation methods to burnup simulations by using post-irradiation examination experiments. The adjusted fission yields lowered the bias and reduced the uncertainty of the simulations. Our approach adjusts the model parameters of the code GEF. We compare the BFMC and MOCABA approaches to data assimilation, focusing especially on the effects of the non-normality of GEF's fission yields. In the application that we present, the best data assimilation framework decreased the average bias of the simulations from 26% to 14%. The average relative standard deviation decreased from 21% to 14%. The GEF fission yields after data assimilation agreed better with those in JEFF3.3. For Pu-239 thermal fission, the average relative difference from JEFF3.3 was 16% before data assimilation and after it was 12%. For the standard deviations of the fission yields, GEF's were 100% larger than JEFF3.3's before data assimilation and after were only 4% larger. The inconsistency of the integral data had an important effect on MOCABA, as shown with the Marginal Likelihood Optimization method. When the method was not applied, MOCABA's adjusted fission yields worsened the bias of the simulations by 30%. BFMC showed that it inherently accounted for this inconsistency. Applying Marginal Likelihood Optimization with BFMC gave a 2% lower bias compared to not applying it, but the results were more poorly converged.
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| 11. |
- Sjöstrand, Henrik, 1978-, et al.
(författare)
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Efficient use of Monte Carlo : The Fast Correlation Coefficient
- 2018
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Ingår i: EPJ N - Nuclear Sciences and Technologies. - : EDP Sciences. - 2491-9292. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Random sampling methods are used for nuclear data (ND) uncertainty propagation, often in combination with the use of Monte Carlo codes (e.g., MCNP). One example is the Total Monte Carlo (TMC) method. The standard way to visualize and interpret ND covariances is by the use of the Pearson correlation coefficient, rho = cov(x, y)/sigma(x) x sigma(y), where x or y can be any parameter dependent on ND. The spread in the output, sigma, has both an ND component, sigma(ND), and a statistical component, sigma(stat). The contribution from sigma(stat) decreases the value of rho, and hence it underestimates the impact of the correlation. One way to address this is to minimize sigma(stat) by using longer simulation run-times. Alternatively, as proposed here, a so-called fast correlation coefficient is used, rho(fast) = cov (x, y)-cov (x(stat), y(stat))/root sigma(2)(x)-sigma(2)(x,stat).root sigma(2)(y)-sigma(2)(y,stat) .In many cases, cov (x(stat), y(stat)) can be assumed to be zero. The paper explores three examples, a synthetic data study, correlations in the NRG High Flux Reactor spectrum, and the correlations between integral criticality experiments. It is concluded that the use of rho underestimates the correlation. The impact of the use of rho(fast) is quantified, and the implication of the results is discussed.
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| 12. |
- Thierry-Chef, Isabelle, et al.
(författare)
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Health effects of ionising radiation in paediatrics undergoing either cardiac fluoroscopy or modern radiotherapy (The HARMONIC project)
- 2023
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Ingår i: The European Journal of Physics N (EPJ-N). - 2491-9292. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The use of ionising radiation (IR) for medical diagnosis and treatment procedures has had a major impact on the survival of paediatric patients. Although the benefits of these techniques lead to efficient health care, evaluation of potential associated long-term health effects is required. HARMONIC aims to better understand the increased risk of cancer and non-cancer effects after exposure to medical IR in children with cancer treated with modern external beam radiotherapy (EBRT) – radiation energy in MeV range – and in children with cardiac defects diagnosed and treated with cardiac fluoroscopy procedures (CFP) – radiation energy in keV range. The project investigates, among survivors of paediatric cancer, potential endocrine dysfunction, cardiovascular and neurovascular damage, health-related quality of life and second (and subsequent) primary cancer (SPC). The cardiac component builds a pooled cohort of approximately 90 000 paediatric patients who underwent CFP during childhood and adolescence to investigate cancer risk following exposure to IR and explore the potential effects of conditions predisposing to cancer. HARMONIC develops software tools to allow dose reconstruction in both EBRT and CFP to enable epidemiological investigations and future optimisation of treatments. With the creation of a biobank of blood and saliva samples, HARMONIC aims to provide a mechanistic understanding of radiation-induced adverse health effects and identify potential biomarkers that can predict these effects.
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