Abdallah Lyoussi

Bio: Abdallah Lyoussi is an academic researcher from French Alternative Energies and Atomic Energy Commission. The author has contributed to research in topics: Neutron & Neutron temperature. The author has an hindex of 14, co-authored 50 publications receiving 476 citations. Previous affiliations of Abdallah Lyoussi include Alternatives & United States Atomic Energy Commission.

Nuclear Heating Measurements in Material Testing Reactor: A Comparison Between a Differential Calorimeter and a Gamma Thermometer

Abstract: Nuclear heating measurements in Material Testing Reactors are crucial for the design of the experimental devices and the prediction of the temperature of the hosted samples. Indeed, nuclear heating is a key input data for the computer codes which simulate temperature reached by samples under irradiation. In the Jules Horowitz Reactor under construction at the CEA Cadarache, the maximal expected nuclear heating levels will be about 15 to 18 W/g and it will be necessary to measure this key parameter with the best accuracy. An experiment was led at the OSIRIS reactor to compare the measurements between the two most appropriate sensors for measuring nuclear heating in MTR; a differential calorimeter and a gamma thermometer. A specific differential calorimeter was designed for low nuclear heating and a standard gamma thermometer was used. Experimental results and Monte-Carlo simulations show that the two sensors are suitable even if the measured energy deposit is different in the two sensors. Finally, these comparisons between the measurements recall that it is primordial to precise in which material and environment the nuclear heating is measured to use this key parameter for designing experimental devices in MTR.

Transuranic waste detection by photon interrogation and on-line delayed neutron counting

Abstract: A comprehensive program is currently in progress at several laboratories for the development of sensitive, practical, non-destructive assay techniques for the quantification of low-level transuranics (TRUs) in bulk solid wastes. This paper describes the method being developed to assay high density TRU waste packages using photon interrogation. The system uses a pulsed electron beam from an electron linear accelerator to produce high-energy photon bursts from a metallic converter. The photons induce fissions in a TRU waste package which is inside an original neutron separating and counting cavity (NS2C). When fission is induced in trace amounts of TRU contaminants in waste material, it provides “signatures” from fission products that can be used to assay the material before disposal. We give here the results from counting photofission-induced delayed neutrons from 239Pu, 235U and 238U in sample matrices. We counted delayed neutrons emitted after each pulse of the LINAC by using the sequential photon interrogation and neutron counting signatures (SPHINCS) technique which had been developed in the present framework. The SPHINCS method enhances the available counts by a factor of about 20 compared with the counting of delayed neutrons only, after the irradiation period. Furthermore, the use of SPHINCS measurement technique coupled with the NS2C facility improves the signal-to-noise ratio by a factor of about 30. This decreases the detection limit. The electron linear accelerator operates at 15 MeV, 140 mA, and 2.5 μs wide pulse at a 50 and 6.25 Hz rate. The dynamics of photofission and delayed neutron production, NS2C advantages and performances, use of an electron linear accelerator as a particle source, experimental and electronics details, and future experimental works are discussed.

The characterization of radioactive waste: a critical review of techniques implemented or under development at CEA, France

Abstract: This review paper describes the destructive and non-destructive measurements implemented or under development at CEA, in view to perform the most complete radioactive waste characterization. First, high-energy photon imaging (radiography, tomography) brings essential information on the waste packages, such as density, position and shape of the waste inside the container and in the possible binder, quality of coating and blocking matrices, presence of internal shields or structures, presence of cracks, voids, or other defects in the container or in the matrix, liquids or other forbidden materials, etc. Radiological assessment is then performed using a series of non-destructive techniques such as gamma-ray spectroscopy, which allows characterizing a wide range of radioactive and nuclear materials, passive neutron coincidence counting and active neutron interrogation with the differential die-away technique, or active photon interrogation with high-energy photons (photofission), to measure nuclear materials. Prompt gamma neutron activation analysis (PGNAA) can also be employed to detect toxic chemicals or elements which can greatly influence the above measurements, such as neutron moderators or absorbers. Digital auto-radiography can also be used to detect alpha and beta contaminated waste. These non-destructive assessments can be completed by gas measurements, to quantify the radioactive and radiolysis gas releases, and by destructive examinations such as coring homogeneous waste packages or cutting the heterogeneous ones, in view to perform visual examination and a series of physical, chemical, and radiochemical analyses on samples. These last allow for instance to check the mechanical and containment properties of the package envelop, or of the waste binder, to measure toxic chemicals, to assess the activity of long-lived radionuclides or pure beta emitters, to determine the isotopic composition of nuclear materials, etc.

Photoneutron production in tungsten, praseodymium, copper and beryllium by using high energy electron linear accelerator

Abstract: This paper presents comparisons between photoneutron production measurements in tungsten, copper, praseodymium and beryllium, and calculated data resulting from the ELEPHANT (ELEctron, PHoton And Neutron Transport) code. Measurements were made using the DGA/ETCA linear electron accelerator located at Arcueil, France. Bremsstrahlung endpoints varying in the 15–25 MeV energy range were used. Detectors were positioned at different angles with respect to the electron beam axis. Each measured value is compared with the corresponding calculated value.

Analysis and recent advances in gamma heating measurements in MINERVE facility by using TLD and OSLD techniques

Abstract: The objective of this study is to develop nuclear heating measurement methods in Zero Power experimental reactors. This paper presents the analysis of Thermo-Luminescent Detector (TLD) and Optically Stimulated Luminescent Detectors (OSLD) experiments in the UO 2 core of the MINERVE research reactor at the CEA Cadarache. The experimental sources of uncertainties on the gamma dose have been reduced by improving the conditions, as well as the repeatability, of the calibration step for each individual TLD. The interpretation of these measurements needs to take into account calculation of cavity correction factors, related to calibration and irradiation configurations, as well as neutron corrections calculations. These calculations are based on Monte Carlo simulations of neutron-gamma and gamma-electron transport coupled particles. TLD and OSLD are positioned inside aluminum pillboxes. The comparison between calculated and measured integral gamma-ray absorbed doses using TLD, shows that calculation slightly overestimates the measurement with a C/E value equal to 1.05 ± 5.3 % (k = 2). By using OSLD, the calculation slightly underestimates the measurement with a C/E value equal to 0.96 ± 7.0% (k = 2).

The joint evaluated fission and fusion nuclear data library, JEFF-3.3

Abstract: The joint evaluated fission and fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides $^{235}\hbox {U}$, $^{238}\hbox {U}$ and $^{239}\hbox {Pu}$, on $^{241}\hbox {Am}$ and $^{23}\hbox {Na}$, $^{59}\hbox {Ni}$, Cr, Cu, Zr, Cd, Hf, W, Au, Pb and Bi are presented. It includes new fission yields, prompt fission neutron spectra and average number of neutrons per fission. In addition, new data for radioactive decay, thermal neutron scattering, gamma-ray emission, neutron activation, delayed neutrons and displacement damage are presented. JEFF-3.3 was complemented by files from the TENDL project. The libraries for photon, proton, deuteron, triton, helion and alpha-particle induced reactions are from TENDL-2017. The demands for uncertainty quantification in modeling led to many new covariance data for the evaluations. A comparison between results from model calculations using the JEFF-3.3 library and those from benchmark experiments for criticality, delayed neutron yields, shielding and decay heat, reveals that JEFF-3.3 performes very well for a wide range of nuclear technology applications, in particular nuclear energy.

Rattling nucleons: New developments in active interrogation of special nuclear material

Abstract: Active interrogation is a vigorous area of research and development due to its promise of offering detection and characterization capabilities of special nuclear material in environments where passive detection fails. The primary value added by active methods is the capability to penetrate shielding—special nuclear material itself, incidental materials, or intentional shielding—and advocates hope that active interrogation will provide a solution to the problem of detecting shielded uranium, which is at present the greatest obstacle to interdiction efforts. The technique also provides a unique benefit for quantifying nuclear material in high background-radiation environments, an area important for nuclear material safeguards and material accountancy. Progress has been made in the field of active interrogation on several fronts, most notably in the arenas of source development, systems integration, and the integration and exploitation of multiple fission and non-fission signatures. But penetration of interrogating radiation often comes at a cost, not only in terms of finance and dose but also in terms of induced backgrounds, system complexity, and extended measurement times (including set up and acquisition). These costs make the calculus for deciding to implement active interrogation more subtle than may be apparent. The purpose of this review is thus to examine existing interrogation methods, compare and contrast their attributes and limitations, and identify missions where active interrogation may hold the most promise.

Prioritization of sustainability indicators for promoting the circular economy: The case of developing countries

Abstract: The concept of the circular economy has gained well-recognition across the world for the past decades. With the heightening risk of the impact of climate change, resource scarcity to meet the increasing world population, the need to transition to a more sustainable development model is urgent. The circular economy is often cited as one of the best solutions to support sustainable development. However, the diffusion of this concept in the industrial arena is still relatively slow, particularly in the developing country, which collectively exerts high potential to be the world's largest economies and workforce. It is crucial to make sure that the development of these nations is sustainable and not bearing on the cost of future generations. Thus, this work aims to provide a comprehensive review of the circular economy concept in developing country context. Furthermore, a novel model is proposed by adopting Fuzzy Analytics Network Process (FANP) to quantify the priority weights of the sustainability indicators to provide guidelines for the industry stakeholders at different stages of industry cycle to transition toward the circular economy. The results revealed that improvement in economic performance and public acceptance are the key triggers to encourage stakeholders for sustainable development. The outcomes serve as a reference to enhance the overall decision-making process of industry stakeholders. Local authorities can adopt the recommendations to design policy and incentive that encourage the adoption of circular economy in real industry operation to spur up economic development, without neglecting environmental well-being and jeopardizing social benefits.

Prioritization of sustainability indicators for promoting the circular economy: The case of developing countries

Abstract: The concept of the circular economy has gained well-recognition across the world for the past decades. With the heightening risk of the impact of climate change, resource scarcity to meet the increasing world population, the need to transition to a more sustainable development model is urgent. The circular economy is often cited as one of the best solutions to support sustainable development. However, the diffusion of this concept in the industrial arena is still relatively slow, particularly in the developing country, which collectively exerts high potential to be the world’s largest economies and workforce. It is crucial to make sure that the development of these nations is sustainable and not bearing on the cost of future generation. Thus, this work aims to provide a comprehensive review of the circular economy concept in developing country context. Furthermore, a novel model is proposed by adopting Fuzzy Analytics Network Process (FANP) to quantify the priority weights of the sustainability indicators to provide guidelines for the industry stakeholders at different stages of industry cycle to transition toward the circular economy. The results revealed that improvement in economic performance and public acceptance are they key triggers to encourage stakeholders for sustainable development. The outcomes serve as a reference to enhance the overall decision-making process of industry stakeholders. Local authorities can adopt the recommendations to design policy and incentive that encourage the adoption of circular economy in real industry operation to spur up economic development, without neglecting environmental well-being and jeopardizing social benefits.