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Concept

Uranium 236

Publications associées (18)

The isotopic signature of U(V) during bacterial reduction

Marinella Mazzanti, Rizlan Bernier-Latmani, Radmila Faizova, Ashley Richards Brown, Margaux Camille Andréa Molinas

The two-step electron transfer during bacterial reduction of UVI to UIV is typically accompanied by mass-independent fractionation of the 238U and 235U isotopes, whereby the heavy isotope accumulates in the reduced product. However, the role of the UV inte ...

2024

Analysis of the preliminary campaign for the PETALE program

Andreas Pautz, Vincent Pierre Lamirand, Axel Guy Marie Laureau, Thomas Jean-François Ligonnet

The PETALE program aims to provide new experimental data to constrain the stainless steel nuclear data. In this frame, a preliminary measurement campaign has been performed to characterize the neutron flux in key positions of the CROCUS reactor and to deve ...

EDP SCIENCES S A2023

Determination of the activity inventory and associated uncertainty quantification for the CROCUS zero power research reactor

Andreas Pautz, Vincent Pierre Lamirand, Mathieu Hursin, Pavel Frajtag

The paper describes the source term estimation of CROCUS, the zero power research reactor of EPFL, to be used for dispersion analysis under accidental conditions. To fulfil regulatory requirements, the source term of the CROCUS fuel is estimated through Mo ...

2019

Non-crystalline tetravalent uranium species in the subsurface: formation and stability

Luca Loreggian

Uranium (U) contamination of ground and surface waters poses an acute hazard on the ecosystem and human health. Since the discovery of microbial U(VI) reduction, U bioremediation has been explored as a promising and cost-effective method compared to tradit ...

EPFL2019

Conceptual Design of a Sustainable Waste Burning Molten Salt Reactor

Boris Aviv Hombourger

For an energy source to qualify as sustainable, it must maximize the efficiency with which it uses natural resources while minimizing the amounts of waste it produces. Currently deployed nuclear power plants however use a very limited amount of the energy ...

EPFL2018

Products of in situ corrosion of depleted uranium ammunition in Bosnia and Herzegovina soils

Rizlan Bernier-Latmani, Barbora Bártová, Yuheng Wang, Konstantin von Gunten

Hundreds of tons of depleted uranium (DU) ammunition were used in previous armed conflicts in Iraq, Bosnia and Herzegovina, and Serbia/Kosovo. The majority (>90%) of DU penetrators miss their target and, if left in the environment, corrode in these postcon ...

Amer Chemical Soc2016

Analysis of Advanced Sodium-cooled Fast Reactor Core Designs with Improved Safety Characteristics

In order to meet the steadily increasing worldwide energy demand, nuclear power is expected to continue playing a key role in electricity production. Currently, the large majority of nuclear power plants are operated with thermal-neutron spectra and need r ...

EPFL2012

Neutronics Experiments and Analysis Related to Strong Moderation Heterogeneity in LWRs

The Supercritical-Water-Cooled Reactor (SCWR) is the Generation IV reactor concept most closely related to current light water reactors (LWRs). The SCWR builds on the vast experience with today's LWRs and supercritical coal-fired power plants. Water at sup ...

EPFL2012

Experimental validation of reaction rate distributions for a SVEA-96+ BWR assembly with hafnium control blades

Rakesh Chawla, Michaël Plaschy

The accurate estimation of reactor physics parameters related to the presence of cruciform absorber blades in boiling water reactors (BWRs) is important for safety assessment and for achieving flexible operation during the cycle. Characteristics that are a ...

Atomic Energy Society of Japan2009

Impact of new gadolinium cross sections on reaction rate distributions in 10x10 BWR assemblies

Rakesh Chawla

Radial distributions of the total fission rate and the238U- capture-to-total-fission (C 8/F tot) ratio were measured in SVEA-96+ and SVEA-96 Optimal assemblies during the LWR-PROTEUS program. Fission rates predicted using MCNPX with JEFF-3.1 cross sections ...

American Nuclear Society2009

Characterisation of radial reaction rate distributions across the 92-pin section of a SVEA-96 Optima2 assembly

Rakesh Chawla, Michaël Plaschy

Characterisation of the SVEA-96 Optima2 boiling water reactor assembly, in terms of the radial distributions of normalised total fission and 238U capture rates, is reported at its central elevation, i.e. at the 92-pin section, where the one-third part-leng ...

Elsevier Science Ltd.2008

Comparison of 3D reaction rate distributions measured in an optima2 BWR assembly with MCNPX predictions

Rakesh Chawla, Michaël Plaschy

As part of a joint research programme between the Paul Scherrer Institute (PSI) and swissnuclear, with the co-operation of the Leibstadt nuclear power plant in Switzerland and fuel suppliers Westinghouse Sweden, measurements and calculations have been made ...

Elsevier Science Ltd.2008

Management of actinide waste inventories in nuclear phase-out scenarios

Rakesh Chawla, Marco Cometto

The improvement of the "radiological cleanliness" of nuclear energy is a primary goal in the development of advanced reactors and fuel cycles. The multiple recycling of actinides in advanced nuclear systems with fast neutron spectra represents a key option ...

Elsevier Ltd2008

Radial and azimuthal 235U fission and 238U capture distributions in BWR UO2 pins: CASMO-4 and MCNP4C versus activation foil measurements

Rakesh Chawla, Michaël Plaschy

In the context of the LWR-PROTEUS program, radial and azimuthal 235U fission (F5) and 238U capture (C8) rate distributions have been calculated for zero-burnup pins of a Westinghouse SVEA-96 Optima2 boiling water reactor fuel assembly using the stochastic ...

ANS2007

Characterisation of high-burnup LWR fuel rods through gamma tomography

Stefano Caruso

Current fuel management strategies for light water reactors (LWRs), in countries with high back-end costs, progressively extend the discharge burnup at the expense of increasing the 235U enrichment of the fresh UO2 fuel loaded. In this perspective, standar ...

EPFL2007

Comparisons of deterministic neutronic calculations with Monte Carlo results for an advanced BWR fuel assembly with hafnium control blades

Rakesh Chawla, Michaël Plaschy, Filippo Tani

From the neutronic viewpoint, the optimization of BWR core designs is strongly related to the accurate determination of flux variations inside and around fuel assemblies. These fluctuations, which are mainly due to the high heterogeneity of the fuel and mo ...

Atomic Energy Society of Japan2006

Optimised non-invasive method to determine 238U-captures-to-total-fissions in reactor fuel

Rakesh Chawla

High-resolution gamma spectroscopy was performed on individual fuel rods of a fresh, highly heterogeneous Boiling Water Reactor (BWR) fuel assembly, after irradiation at low power in the PROTEUS reactor at PSI, to determine the ratio of neutron captures in ...

Elsevier2006

Within-pin 238U-capture distributions: CASMO-4 and MCNP vs. activation foil measurements

Rakesh Chawla

The design of modern BWR assemblies is governed by general requirements such as safe and reliable performance, optimal fuel utilization and cycle length, and a high degree of flexibility in reactor operation. These requirements are fulfilled via the use of ...

ANS2005