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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

The EMC: Development of a New Equipment for Recovering Old Nuclear Wastes From Fontenay-aux-Roses CEA Center - 18017 - 18471

The discharge of nuclear wastes from the Fontenay-aux-Roses CEA center, to conform with storage facilities, is a key issue of the cleaning and dismantling program, both for old nuclear wastes - produced during the R and D nuclear activities period-, and for the current wastes from the dismantling activities. In order to address this double issue, a new equipment, specific to mid-radiant and highly-radiant (MI/HI) solid wastes, is being designed by CEA. The Measurement and Conditioning Equipment, (EMC) aims at radiological characterization of wastes and their conditioning so that they respect the acceptance criteria of the storage facilities. The EMC is currently being studied and should be operated in 2020. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Perception of the risks of CEA Cadarache Research Centre: Reconciling the Fears with the Challenges - 19362

The CEA Cadarache Research Centre is one of the 10 research centres of the French Commission of Atomic and Alternative Energies (CEA). Distributed throughout various research platforms, the studies of the Centre focus on nuclear fission, nuclear fusion, new energy technologies (hydrogen, solar, biomass) and fundamental research in the field of vegetal biology. The French government asked nuclear professionals to open their communication channels and to provide the Local Information Commission (CLI) and the public with all the information they requested. In its concern for its image and following a policy of transparency pursued over these last few years, the Cadarache Centre has sought to reduce the population's anxiety to a level judged consistent with the actual risks involved in the activities carried out within the Cadarache Research Centre. The Communications and Public Affairs Department has been entrusted with the task of developing a communication strategy aimed at improving the surrounding population's perception of the Centre. In a first step, we tried to find out what the current perception of the Cadarache Research Centre might be by conducting a survey among the local population. Our results showed a better knowledge of the Centre's activities than had been anticipated but there is still a lack of understanding that could lead to unnecessary anxiety in the event of an incident on the site. We worked on the elaboration of the communication campaign in consultation with psychology experts who took into account the results of the survey. This year, four actions will be implemented along with the decision to conduct a new survey every two to three years. Furthermore, the setting up of a lasting structure of exchange with the population will be pursued in a form that has yet to be determined. The effects of our communication campaign have now been evaluated following the results of this second survey, two years later. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Comparison of Results from Recent NNSA and CEA Measurements of the 239 Pu(n, f) Prompt Fission Neutron Spectrum

The National Nuclear Security Administration (NNSA)/DP French Alternative Energies and Atomic Energy Commission (CEA)/DAM agreement on cooperation on fundamental science is a U.S.-French collaborative effort to combine intellectual and experimental resources and further the relevant nuclear science. Recently, both the NNSA and CEA experimental teams performed high-statistics measurements of the 239 Pu(n, f) prompt fission neutron spectrum (PFNS) at the Los Alamos Neutron Science Center, both of which were recently published in the journal Physical Review C. These separate measurements used the same experimental area and a common neutron detector array, but differ in many aspects, including background assessments, data acquisition systems and philosophies, fission detectors, and PFNS extraction techniques. Hence, some aspects of the experimental methods and associated uncertainties are highly correlated while others are independent. The results from both measurements broke new ground for PFNS measurements given their higher accuracy and more detailed study of corrections necessary for the measured quantity compared to existing literature measurements, and both will significantly impact PFNS nuclear data evaluations for the foreseeable future. Here, the focus of this work is to document a comparison of the results from these distinct measurements in terms of the acquired data, the PFNS results, and the measured average PFNS energies. While systematic differences between the PFNS results are present on the 1–3% level, the acquired data relative to each respective measurement at low incident neutron energies are in remarkable agreement, as are the conclusions regarding the magnitude and position of features in the PFNS relating to second-chance fission, third-chance fission, and pre-equilibrium neutron emission.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Spectral indices measurements using miniature fission chambers at the MINERVE zero-power reactor at CEA using calibration data obtained at the BR1 reactor at SCK.CEN

Spectral indices are parameters of major importance to characterize a multiplying medium and to evaluate performances of neutronics calculation tools as well as quality of associated nuclear data. Experiments performed in 2004 at the CEA MINERVE facility loaded with the R1-UO{sub 2} lattice [1], using homemade miniature fission chambers and calibration data acquired at the SCK.CEN BR1 facility in 2001 [2], resulted in ambivalent conclusions. On one hand, spectral indices involving only fissile isotopes gave relevant results and consistent discrepancies between calculation and experiment. On the other hand, spectral indices involving both fissile and fertile isotopes showed inconsistent results depending on the type of calibration data used. In particular, the {sup 238}U(n,f)/{sup 235}U(n,f) spectral indices resulted in values far from the calculations in all cases. In 2004, those differences between measurement and calculation were mainly attributed to an imprecise knowledge of the isotopic composition of the deposits loaded in the {sup 238}U chambers. At that time, priorities in the development of programs in MINERVE and other considerations about the manufacturing and calibration of new fission chambers did not allow to further investigate these discrepancies. In 2009, the preparation of a new program at the EOLE facility [1] and changes in the regulatory framework for management of fission chambers motivated the manufacturing of new detectors. At the same time, the re-installation of the R1-UO{sub 2} lattice in MINERVE gave the opportunity to carry out a new spectral indices measurement campaign. Nevertheless, although the isotopic composition of active deposits was better known than previously, the comparison between experimental results and calculations still resulted in inconsistent discrepancies. A sensitivity study indicated afterwards that, among all parameters to be considered for the analysis and the assessment of final uncertainty, calibration data have the greatest impact. In April 2010, a new calibration campaign conducted again at the BR1 facility allowed the CEA to reanalyze the spectral indices measurements performed in 2009. With this new set of calibration data, the experimental values of spectral indices finally matched the calculation results within the uncertainty margins. In addition, the confrontation of data from 2001 and 2010 calibration campaigns, both performed with the same experimental conditions, allowed to shed on the light dead time correction issues in the monitoring of calibration measurements. At the end, this also explained the inconsistencies observed during the 2004 campaign. This paper first, presents the two different analysis methods for getting the experimental value of a spectral index and, lists main parameters that influence the determination of the experimental value. It then details the calibration processes that are set-up at the MINERVE and BR1 facilities, describes the various experiments carried out and finally comments the results obtained. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2012

Spectral indices measurements using miniature fission chambers at the MINERVE zero-power reactor at CEA using calibration data obtained at the BR1 reactor at SCK.CEN

Spectral indices measurements performed in 2004 at the CEA MINERVE facility loaded with the R-UO{sub 2} lattice, using calibration data acquired at the SCK center dot CEN BR1 facility in 2001, resulted in ambivalent conclusions. On one hand, spectral indices involving only fissile isotopes gave consistent discrepancies between calculation and experiment. On the other hand, spectral indices involving both fissile and fertile isotopes, in particular the {sup 238}U(n, f)/{sup 235}U(n, f) spectral index, showed inconsistent results depending on the type of calibration data used. For different reasons, no definitive explanation was given at that time. In 2009, the preparation of the AMMON program at the EOLE facility motivated the manufacturing of a new set of detectors. At the same time, the re-installation of the R1-UO{sub 2} lattice in MINERVE provided the opportunity to carry out again a spectral indices measurement campaign. Nevertheless, although the isotopic compositions of active deposits were better known than previously, the comparison between experimental results and calculations still lead to inconsistent discrepancies. In April 2010, a new calibration series conducted again at the BR1 facility allowed the CEA to reanalyze the spectral indices measurements performed in 2009. With these very latest calibration data, experimental values of spectral indices finally matched calculations within the uncertainty margins. This paper also sums up the work that has been achieved to explain the incoherencies observed in 2004. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2022

CEA Contribution to the PIP-II Linear Accelerator

The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018, and will deliver 10 low-beta cryomodules as In-Kind Contribution to the PIP-II project, with cavities supplied by LASA-INFN and power couplers and tuning systems supplied by Fermilab. This paper presents the CEA scope of work that includes the design, manufacturing, assembly and tests of the cryomodules and the upgrade of the existing infrastructures to the PIP-II requirements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Neutron Activation and Thermoluminescent Detector Responses to a Bare Pulse of the CEA Valduc SILENE Critical Assembly

This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 11, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

Miller, Thomas Martin↗
DOE OSTI2016

Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6 LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6 LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2024

Mechanical Engineering Safety Note 1012910313-AA: CEA LTIC Structural Integrity

The LRU Target Insert Cryostat (LTIC) is the end effector of the NIF Cryogenic Target Positioner (CryoTarpos), which houses a cooling system to support cryogenic target experiments at NIF. The LTIC maintains a target at micron level positional stability and millikelvin level temperature stability during a NIF shot and is also subject to a portion of the blast load governed by the solid angle subtended by the blast shield at the front of the system. This MESN evaluates loading of the CEA LTIC, a redesigned LTIC to be fielded at Laser Megajoule (LMJ) in France, which has been designed to lay out requirements agreed upon between LLNL and CEA personnel. The LMJ version of CryoTarpos is referred to as the PCC. A high-level system overview of the LTIC on the PCC is shown.

42 ENGINEERING↗
DOE OSTI2024

Stable and high voltage and power output of CEA-MFCs internally connected in series (iCiS-MFC)

The voltage output of a single MFC is normally less than 0.8 V, often less than 0.3 V at maximum power output, which greatly limits the application of MFCs. When MFCs are scaled up, however, increasing reactor size has typically resulted in decreased power density. In this study, we developed a novel MFC configuration that contains multiple cloth electrode assemblies in which the MFCs were internally connected in series (iCiS-MFC). The iCiS-MFC, equivalent to 3 CEA-MFCs, produced a high voltage output over 1.8 V and a maximum power density of 3.5 W m -2 using carbon cloth cathodes containing activated carbon as the catalyst. This power density is 6% higher than that reported for a similar smaller CEA-MFC, indicating that power can be maintained during scale-up with a greater than 33-fold increase in total cathode surface area and greater than 20-fold increase in reactor volume. High stability was also demonstrated based on the performance of the iCiS-MFC over a period of one year of operation. The high power and stability is likely due, in part, to a more efficient means of current collection through the internal series connection, which also avoids the use of expensive current collectors. These results clearly demonstrate the great potential of this MFC design for further scaling-up.

25 ENERGY STORAGE↗
NASA NTRS1982

Comparison of the CEAS and Williams-type barley yield models for North Dakota and Minnesota

The CEAS and Williams type models were compared based on specified selection criteria which includes a ten year bootstrap test (1970-1979). Based on this, the models were quite comparable; however, the CEAS model was slightly better overall. The Williams type model seemed better for the 1974 estimates. Because that year spring wheat yield was particularly low, the Williams type model should not be excluded from further consideration.

Leduc, S.↗
DOE OSTI2012

Light ion source for proton/deuteron production at CEA Saclay for the Spiral2 project

The production of rare radioactive ion beam (RIB) far from the valley of stability is one of the final purposes of the Spiral2 facility in Caen. The RIB will be produced by impinging a deuteron beam onto a carbon sample to produce a high neutron flux, which will interact with a uranium target. The primary deuteron beam is produced by an ion source based on ECR plasma generation. The deuteron source and the low energy beam transport (LEBT) has been assembled and tested at CEA Saclay. Diagnostics from other laboratories were implemented on the LEBT in order to characterize the deuteron beam produced and compare it to the initial simulations. The ion source has been based on a SILHI-type source, which has demonstrated good performances in pulsed and continuous mode, and also a very good reliability on long term operation. The 5 mA of deuteron beam required at the RFQ entrance is extracted from the plasma source at the energy of 40 kV. After a brief description of the experimental set-up, this article reports on the first beam characterization experiments.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Materials Data on CeAs by Materials Project

CeAs is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ce3+ is bonded to six equivalent As3- atoms to form a mixture of corner and edge-sharing CeAs6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ce–As bond lengths are 2.99 Å. As3- is bonded to six equivalent Ce3+ atoms to form a mixture of corner and edge-sharing AsCe6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2013

BDDR, a new CEA technological and operating reactor database

The new application BDDR (Reactor database) has been developed at CEA in order to manage nuclear reactors technological and operating data. This application is a knowledge management tool which meets several internal needs: -) to facilitate scenario studies for any set of reactors, e.g. non-proliferation assessments; -) to make core physics studies easier, whatever the reactor design (PWR-Pressurized Water Reactor-, BWR-Boiling Water Reactor-, MAGNOX- Magnesium Oxide reactor-, CANDU - CANada Deuterium Uranium-, FBR - Fast Breeder Reactor -, etc.); -) to preserve the technological data of all reactors (past and present, power generating or experimental, naval propulsion,...) in a unique repository. Within the application database are enclosed location data and operating history data as well as a tree-like structure containing numerous technological data. These data address all kinds of reactors features and components. A few neutronics data are also included (neutrons fluxes). The BDDR application is based on open-source technologies and thin client/server architecture. The software architecture has been made flexible enough to allow for any change. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2012

Treatment of G1 Baskets at the CEA Marcoule Site - 12027

In the dismantling program for the first-generation French reactors in accordance with the nonproliferation treaty, the CEA is in charge of cleanup and dismantling operations for the facilities at Marcoule, including the decladding units. The G1 decladding was built between 1955 and 1957 in order to de-clad spent fuel elements from the G1 plutonium-producing reactor and prepare them for dissolution. The facility was also used for interim storage of G1, G2 and G3 fuel dissolution baskets, which had been used during plant operation for transfer (from the decladding facility to the UP1 plant) and/or dissolution of spent fuel elements. One of the cleanup projects involves recovery of the baskets, which will be cut up, sorted, and conditioned in metal bins. The bins will be immobilized with cement grout, then transferred to the onsite solid waste conditioning facility (CDS) and to the repository operated by the French National Radioactive Waste Management Agency (ANDRA). The project is now in progress, after special safety permits were issued and measurement stations and dedicated tools were developed to handle all types of baskets (which differed according to their origin and use). The disposal of all the baskets is scheduled to last 2 years and will produce 55 metal waste bins. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

CEA in policies and plans: UK case studies

This paper examines how cumulative effects assessment (CEA) has been considered in Strategic Environmental Assessments (SEA) of regional and local plans in a number of case studies in the UK. Initially, the paper presents the legislative and regulatory requirements for assessing cumulative effects in plans and programmes in the UK. The two approaches for assessing plans in the UK, Sustainability Appraisal (SA) and SEA are discussed and in most cases, a combined SA and SEA process is undertaken by Regional and Local Planning Authorities. The strengths and weaknesses of this approach are explored, as well as their usefulness in decision making. There are problems relating to baseline, establishing trends and predicting cumulative effects at the strategic level. The issues in assessing cumulative effects within this SA/SEA framework are discussed and recommendations for improvements are made.

99 GENERAL AND MISCELLANEOUS↗