Atomic Energy Commission Research Articles

DETERMINATION OF HG IN HAIR OF MINERS IN ABU HAMMED CITY (INDISCRIMINATE MINING AREA) USING DIRECT MERCURY ANALYZER, SUDAN

15Nov 2019 DETERMINATION OF HG IN HAIR OF MINERS IN ABU HAMMED CITY (INDISCRIMINATE MINING AREA) USING DIRECT MERCURY ANALYZER, SUDAN M. Ismail , A. S. Elhag and Elamin E.Elamin Chemistry Department ,Faculty of Science ,University of Khartoum Sudan Atomic Energy Commission

INSTITUT LAUE-LANGEVIN (ILL) AS A FORM OF SCIENTIFIC COOPERATION

The integration of states in the field of education has given rise to the expansion of various forms of cooperation in this area. The subject of the study is one of the large-scale scientific projects called "megasience" — Institut Laue-Langevin (ILL), based in Grenoble, France. Such international research centers are designed to achieve breakthrough discoveries, like the Large Hadron Collider (LHC) in Europe, the Laser Interferometric Gravitational-wave Observatory (LIGO) in the United States, and neutron research through the research reactor complex PIK, under construction in Russia. Large research infrastructures are an important phenomenon of public life. In France, megasience installations are officially called "very large research infrastructures", briefly TGIR, in Australia — "landmark research infrastructures".The Institut Laue-Langevin is established as a national legal entity and is managed by three partner countries: France through the French Alternative Energies and Atomic Energy Commission (CEA) and the French National Centre for Scientific Research (CNRS); Germany through the Jülich Research Centre (FZJ) and the United Kingdom through the Science and Technology Facilities Council (STFC).This form of cooperation between countries, integration of states in the field of education has a number of positive aspects and can be used in Russia to find the most effective model for organizing mega-science projects. Thus, ILL make ot possible to use different sources of funding-funds from both the state and private research and grants, as well as European projects. The ILL provides for the possibility of diverse cooperation and participation of various states, the involvement of scientists and individuals, including non-European countries, open membership. The positive features are also the ease of management and reorientation of ILL, flexibility, as well as the ease of cooperation with various institutions of both national and European and international level.

Infrasound observations of sprites associated with winter thunderstorms in the eastern mediterranean

Abstract Sprites are transient luminous events (TLEs) that occur at mesospheric altitudes between 50 and 90 km. They last up to several milliseconds, and are caused mostly by positive lightning discharges from the thunderstorm cells below. Infrasound from sprites was first observed in detail a decade ago by a team from the French Atomic Energy Commission (CEA), as part of a renewed international interest in infrasound measurements brought about by the Comprehensive Nuclear Test Ban Treaty (CTBT) ( Farges et al., 2005 ). They used optical images of sprites obtained during the EuroSprite observation campaign in order to form the temporal and azimuthal basis necessary for searching for the infrasound signatures from these events, which appear as unique “chirp” or “inverted chirp” signatures depending on the sprite's distance from the infrasound array. In this paper we follow this methodology to see if the nascent Israeli infrasound arrays can detect these signals from sprites in the Eastern Mediterranean, for which there are nearly 8 years of winter-time optical observations. We calculated the expected arrival time of the infrasound from optically observed sprites, and then used a basic ray-tracing method in order to confirm that we were in fact able to observe several of these sprites, at various distances, exhibiting both “chirp” and “inverted chirp” signals. We then compared these observations with observations of lightning activity made by the World Wide Lightning Location Network (WWLLN).

A GIS-based site investigation for nuclear power plants (NPPs) in Nigeria

The Nigeria Atomic Energy Commission (NAEC) has identified some sites for possible constructions of nuclear power plants in Nigeria. This paper addresses the conduct of a Geographic Information System (GIS) based suitability assessment of these sites for the proposed Nuclear Power Plant. Attempts to recommend sites for the nuclear power plants and other major constructions in Nigeria have been made in view of historical and recent occurrences both at regional and local level, with earthquake occurrences in Ghana (18th December, 1636 Ms = 5.7; 1862 ML~ 6.5 and Ms ≥ 6.5; 11th February, 1907 and 22nd of June, 1939 Ms~ 6.5 and mb~ 6.4), Guinea 22nd December, 1983 with (MW~ 6.3) coupled with recent activities of volcanic eruption of mount Cameroun (1986, 1999, 2000). The buried equatorial fault lines emanating from the seismically active zones of the Gulf of Guinea are in reactivation state. This study entails the use of GIS to integrate available administrative and comprehensive tectonic maps of Nigeria. Database for the recommended sites is in line with the guidelines and recommendations of the International Atomic Energy Agency. In this paper, recommended sites are those where seismic and other hazards are considered to be at the bearest minimum.

Design and Analysis of a Metallic Uranium Reactor Type-Pump Using the Magnesiothermy Process

This paper shows a methodology to obtain metallic uranium through a magnesiothermy process. Chile has two experimental reactors operated by the “Chilean Nuclear Energy Commission” (CCHEN). One is 5 MW and the other is 10 MW. In order to fulfill international agreements about nuclear energy for testing purposes of these reactors, CChEN purchased 19.9% enriched uranium hexafluoride, also known as the limit of Low Enriched Uranium (LEU). Due to the capacity of these reactors, they need high-density uranium compounds for their fuel, in order to work with LEU. For this reason, the uranium needs a previous conversion into metallic uranium. The conversion laboratory carried out experiences for reduction of UF4 with Mg. The main purpose of this study was to analyze the operating conditions under which the reduction reaction takes place, the designed method and the equipment and materials used. The raw material used was dehydrated UF4, prepared by electrolytic reduction and commercial purity Magnesium. The reaction took place in a cylindrical reactor made of low alloy steel, with a conic section in the lower part. The internal zone was coated with a 2.5 cm thick layer of CaF2. The process started by applying external heating, according to a heating program, developed specially for this purpose. The reduction reaction took place starting at 650°C. The result was a cylinder of uranium metal and MgF2 slag. The crossed cut uranium cylinder showed a smooth and homogeneous surface without inclusions of slag, pores or blisters. The yield of the reaction was of the order of 75% with respect to the expected theoretical value. The uranium cone obtained fulfilled the required conditions for source material for nuclear fuel fabrication, with a uranium content of 97.5%.

X-ray intensity, stability, and source size characterizations for the 10 kV/5 mA water cooled upgraded Manson source at the Atomic Energy Commission for Laser MégaJoule Facility.

Calibration of x-ray cameras integrated within plasma diagnostics for Laser MégaJoule's experiment is of great interest for interpretations of physical phenomena. At the Atomic Energy and Alternative Energy Commission, an x-ray calibration laboratory has been trying for many years to provide the most relevant calibrations. In the soft x-ray range (<1.5 keV), a model 5 Manson source is used in combination with a concave grating monochromator equipped permanently with an absolute calibrated silicon drift detector. To reduce the calibration time achieved with this experimental setup, the Manson source has been modified to reach an emission current of up to 5 mA (100 µA for a standard source model) while keeping the x-ray monochromatic intensity constant within ∼2% for several operating hours. A water cooling system has been integrated within the anode carousel and an emission current regulation system inside a completely redesigned power supply. In this work, we present characterization of the source size and x-ray intensity as a function of both source voltage and emission current, as well as the stability of this new source. Both arms of the source have been used: one for monitoring the monochromatic spectra and x-ray intensity and the other to measure the source size. An x-ray spot was observed to be evolved from the oval shape toward the annular one as the emission current increases. For fixed emission current, the source size is reduced as the voltage increases. The x-ray intensity has significantly been increased to a maximum factor of ∼20 (depending on the anode) while being constant within around 2% as expected.

2D Ultrasonic Antenna System for Imaging in Liquid Sodium.

Ultrasonic techniques are developed at CEA (French Alternative Energies and Nuclear Energy Commission) for in-service inspection of sodium-cooled reactors (SFRs). Among them, an ultrasound imaging system made up of two orthogonal antennas and originally based on an underwater imaging system is studied for long-distance vision in the liquid sodium of the reactor’s primary circuit. After a description of the imaging principle of this system, some results of a simulation study performed with the software CIVA in order to optimize the antenna parameters are presented. Then, experimental measurements carried out in a water tank illustrate the system capabilities. Finally, the limitations of the imaging performances and the ongoing search of solutions to address them are discussed.

An exoskeleton controlled by an epidural wireless brain–machine interface in a tetraplegic patient: a proof-of-concept demonstration

Approximately 20% of traumatic cervical spinal cord injuries result in tetraplegia. Neuroprosthetics are being developed to manage this condition and thus improve the lives of patients. We aimed to test the feasibility of a semi-invasive technique that uses brain signals to drive an exoskeleton. We recruited two participants at Clinatec research centre, associated with Grenoble University Hospital, Grenoble, France, into our ongoing clinical trial. Inclusion criteria were age 18-45 years, stability of neurological deficits, a need for additional mobility expressed by the patient, ambulatory or hospitalised monitoring, registration in the French social security system, and signed informed consent. The exclusion criteria were previous brain surgery, anticoagulant treatments, neuropsychological sequelae, depression, substance dependence or misuse, and contraindications to magnetoencephalography (MEG), EEG, or MRI. One participant was excluded because of a technical problem with the implants. The remaining participant was a 28-year-old man, who had tetraplegia following a C4-C5 spinal cord injury. Two bilateral wireless epidural recorders, each with 64 electrodes, were implanted over the upper limb sensorimotor areas of the brain. Epidural electrocorticographic (ECoG) signals were processed online by an adaptive decoding algorithm to send commands to effectors (virtual avatar or exoskeleton). Throughout the 24 months of the study, the patient did various mental tasks to progressively increase the number of degrees of freedom. Between June 12, 2017, and July 21, 2019, the patient cortically controlled a programme that simulated walking and made bimanual, multi-joint, upper-limb movements with eight degrees of freedom during various reach-and-touch tasks and wrist rotations, using a virtual avatar at home (64·0% [SD 5·1] success) or an exoskeleton in the laboratory (70·9% [11·6] success). Compared with microelectrodes, epidural ECoG is semi-invasive and has similar efficiency. The decoding models were reusable for up to approximately 7 weeks without recalibration. These results showed long-term (24-month) activation of a four-limb neuroprosthetic exoskeleton by a complete brain-machine interface system using continuous, online epidural ECoG to decode brain activity in a tetraplegic patient. Up to eight degrees of freedom could be simultaneously controlled using a unique model, which was reusable without recalibration for up to about 7 weeks. French Atomic Energy Commission, French Ministry of Health, Edmond J Safra Philanthropic Foundation, Fondation Motrice, Fondation Nanosciences, Institut Carnot, Fonds de Dotation Clinatec.

P1.10-06 Pathological Characterization of Radon-Induced Lung Cancer in Rats

Radon is a radioactive gas, considered the leading cause of lung cancer in non-smokers. Although the risk of lung cancer is linear, there is no safe level and even low dose can be associated with risk. In humans, no specific pathological subtypes of lung cancer have been clearly associated with radon. In animals, the French Atomic Energy Commission (CEA) exposed to low dose of radon (25 working level month, WLM) a large cohort of rats in a radon-exposure chamber, showing lung cancer induced by low exposure (Chameaud J, Radiation Prot Dosimetry 1984). We aimed to describe pathological features of radon-induced tumors in rats from the CEA’s cohort. Retrospective assessment of archival samples available of the rats exposed to low-dose radon in the Laboratoire de Pathologie Pulmonaire Experimentale, COGEMA (France), between 1989 and 1992. Autopsy reports were also reviewed. The pathological assessment was performed for a thoracic oncology pathologist (JA) in H&E staining slides according to the current WHO histological classification. Samples from 117 rats were collected. Among 104 tumors, to date the analysis has been performed in 94. Forty tumors (43%) were classified as malignant, 28 (30%) as uncertain malignant potential (UMP) and 26 (28%) benign. In 2 rats (2%) synchronous malignant and non-malignant tumors were observed. Among the malignant tumors, 23 (58%) were epithelial and 17 (42%) non-epithelial. Lung carcinoma was the most common primary epithelial tumor (n=10, 43%), followed by abdominal area tumors (n=5, 22%), and thyroid (n=3, 13%). In the UMP group, 7 (25%) were epithelial and 21 (75%) non-epithelial, with no lung tumors observed. In the benign group, most of them (n=24, 92%) were epithelial, with 4 cases with lung atypical adenomatous hyperplasia-like lesions; 2 synchronous with other malignant tumors (n=1 lymphoma, n=1 cutaneous squamous cell carcinoma). A total of 26 tumors (27%) had thoracic involvement: 4 (15%) primary lung non-malignant lesions, 11 primary lung malignancies (42%) and 11 with metastases from other tumors (42%). As primary malignant lung tumors, we observed: 7 (64%) adenocarcinoma in situ, one papillary adenocarcinoma, one undifferentiated large cell carcinoma with bilateral metastases, one metastatic squamous carcinoma and one metastatic undifferentiated tumor, compatible with sarcoma In this cohort of radon-induced tumors in rats, we observed different tumor types, from non-malignant lesions to aggressive malignancies, with predominance of epithelial tumors. Lung carcinoma was the most common primary tumor and adenocarcinoma the histological subtype more observed, with histological similarities with humans.

Evaluation of Radiofrequency and Extremely Low-Frequency Field Levels at Children's Playground Sites in Greece From 2013 to 2018.

From 2013 to 2018, in-situ measurements of radiofrequency (RF) electromagnetic fields (EMF) and extremely low-frequency (ELF) electric and magnetic fields in 317 existing and under-construction children's playground facilities, in 16 municipalities all over Greece, were carried out by the Greek Atomic Energy Commission (EEAE). These measurements were conducted following legislative framework established in 2009, which requires that compliance with the established exposure limits for EMFs should be verified in playground areas. The results are presented by the value of the electric field (E) and exposure ratio (Λ) for the RF EMF, as well as the value of the electric field (E) and magnetic flux density (B) for the ELF electric and magnetic fields. Statistical analysis tools were applied on measurement data and conclusions have been made, taking into consideration: (i) environment type (urban/suburban), and (ii) vicinity to any transmitting installations. Measurement results correspond to the typical EMF background levels for each environment type. Concerning the environment type, RF EMF, and ELF electric/magnetic field measurements reveal no differentiation between urban and suburban environments. Bioelectromagnetics. 2019;40:602-605. © 2019 Bioelectromagnetics Society.

Frequency of Homocysteinemia in Young Ischemic Stroke Patients and Its Relationship with the Early Outcome of a Stroke.

ObjectiveTo find out the frequency of hyperhomocysteinemia in young ischaemic stroke patients and its relationship with early morbidity and mortality.MethodsThis prospective study was conducted on young ischemic stroke patients in Pakistan Atomic Energy Commission General Hospital, Islamabad. Ischaemic stroke patients of age < 45 years were selected from both the outpatient and inpatient departments. A fasting venous blood sample was sent for analysis. Data was collected through a structured proforma and were analyzed using SPSS 24.0 (IBM Corp, Armonk, NY, US). The outcome was measured at discharge using the modified Rankin scale.ResultsThe mean age of the 71 patients in the study was 35.8 years. Overall, 36 (50.7%) cases had hyper-homocysteinemia. The frequency was significantly higher in males and in the age group 36-45 years (63.4%). Levels of homocysteine did not significantly affect the outcome at discharge.ConclusionHyperhomocysteinaemia, a modifiable risk factor for ischaemic stroke, was seen in about half of young stroke patients. The levels of homocysteine did not correlate with early stroke outcome.

Wall-Modeled Large Eddy Simulation of the Flow Through PWR Fuel Assemblies at ReH = 66 000—Validation on CALIFS Experimental Setup

The EDF aims to identify what causes fuel assembly vibrations in pressurized water reactors. The present work focuses on the validation of pressure fluctuations along the central rod of a 5 × 5 configuration for wall-modeled large eddy simulations. New experiments, called CALIFS, have been carried out by the Atomic Energy Commission (CEA) on a 5 × 5 mixing vane grid (MVG) in the framework of the Fuel Assembly EDF/CEA/FRAMATOME tripartite project. In addition to pressure drop and velocity measurements using particle image velocimetry, pressure measurements have been performed along the central rod. The computational domain is representative of a span of the experimental mock-up composed of a 5 × 5 rod bundle equipped with a split-type MVG. The hydraulic Reynolds number is equal to 66 000 and periodic boundary conditions are imposed in the streamwise direction. The mesh is fully hexahedral and conformal. Computations give very satisfactory results for the pressure drop, the mean velocity, and the Reynolds stresses at different locations. The root-mean-square of the pressure along the central rod is also compared to experimental data at different heights. The behavior is in very good agreement up to five hydraulic diameters downstream of the MVG.

Heavy-ions induced scintillation experiments

The French Alternative Energies and Atomic Energy Commission (CEA) is developing fission chambers relying on gas luminescence capable of high gamma signal rejection and self-diagnostic capabilities allowing high dependability level. Scintillation yield of noble gases by energetic ions (average initial energy between 68 MeV to 99 MeV) is evaluated for nuclear power reactor instrumentation application. Neutron interaction with fissile material can provide energetic heavy ions at a rate proportional to the neutron flux. The understanding of fission fragments as excitation source is required for noble gas scintillation neutron detectors. This work deals with evaluation of the optical signal heavy-ions induced in cold plasma. A dedicated experimental device (PSEG) is presented. Plutonium 238 is selected as a continuous source of heavy ions in order to avoid technological constraints of neutron flux tests, as a first step in the experimental validation process. Estimation of signal power is performed as well as Optical Emission Spectrum analysis. As expected, no Partial Local Thermodynamic Equilibrium is satisfied from experiments. The effect of pressure on the visible to infrared emission spectrum is analysed.

Quantifying Water in PEM Fuel Cell Catalyst Layer with Small Angle Neutron Scattering

A polymer electrolyte membrane (PEM) fuel cell requires effective water management to achieve high performance. Balancing the water content and distribution is particularly important in a catalyst layer (CL), consisted of catalyst on carbon (typically Pt/C) covered by ionomer films. The accumulation of product water in the pores impedes reactant transport; however, simultaneously, the lack of water results in poor proton conductance in the ionomer. A diagnostic tool for measuring water content within the CL of an operating fuel cell is necessary for the development of the CL, especially for low Pt loading and non-precious metal group catalyst [1]. The common method for measuring water content in operando fuel cells is imaging based on synchrotron X-ray and neutron sources [2]. By using imaging method, water in the membrane electrode assembly (MEA) can be visualized on the micron-scale pixel resolution. However, this is not an ideal technique for probing water content in the CL for two main reasons: (1) the water in the ionomer cannot be distinguished from that in the pores, and (2) the spatial resolution is often not sufficient (as it is several times of the pixel resolution). At the French Alternative Energies and Atomic Energy Commission (CEA), we have developed in situ small angle scattering (SAS) techniques for fuel cell application based on neutron and synchrotron X-ray sources (Institut Laue-Langevin and European Synchrotron Radiation Facility). These techniques utilize focused neutron or X-ray beam to scan the areas of the MEA, each scanned point producing a scattering pattern. By radial averaging, the scattering pattern is converted into Q-range. The scattering due to the perfluorosulfonic acid (PFSA) ionomer produce a peak in the range of 0.1-0.25 Å-1, which arises from the separation between hydrophobic and hydrophilic domain. The water uptake in ionomer can be deduced from the shift of the peak position resulting from the swelling upon hydration. On the other hands, the overall water content can be obtained by either direct transmission or analyzing the high Q-range (0.4-0.45 Å-1). We previously measured liquid water accumulation (in the channels and the GDL) and water uptake in the membrane by through-plane SAS (i.e. the fuel cell is aligned perpendicular to the beam) [3]. Recently, we have further refined the custom fuel cell and SAS technique to probe water content only in the CLs. This was accomplished by developing a cell with an active area of 0.1 cm2 (0.1 mm wide in the path of the beam) and narrowing the beam size to 3 and 15 µm (for X-ray and neutron, respectively). This work will provide an overview of in situ SAS technique for fuel cells and focus on the comparison of two types of SAS investigations (neutron- vs. synchrotron X-ray-based).

Thyroid Uptake of Tc-99m and Its Agreement with I-131 for Evaluation of Hyperthyroid Function

Thyroid uptake and scintigraphy using Tc-99m pertechnetate has proven to be more advantageous than with I-131 iodide, since the images have better quality, the procedure is faster and the patient is submitted to a lower radiation dose. Tc-99m has been used worldwide to study the thyroid function because of a number of advantages such as short half-life, short biological half-life, short effective half-life, short retention in gland and no Beta (β-) radiation, providing low dose to gland (10,000 times less than that of I-131), low cost and readily availability. Otherwise, I-131 with its high radiation burden (1-3 rad/mCi) has long half-life and causes Beta (β-) particle emission. Its main gamma photon has high energy (364 keV) which also causes poor image quality. The experiment is carried out at the Institute of Nuclear Medicine and Allied Sciences (INMAS), Bangladesh Atomic Energy Commission, Dhaka Medical College Hospital Campus, Dhaka-1000. In the present work, the study consists of 109 patients (76 female and 33 male) with ages ranging from 14 to 66 years. The patients studied with Tc-99m found to be hyperthyroid of 57 and in case of I-131, the findings were 60. The agreement between I-131 and Tc-99m is 95% and the correlation coefficient, r between Tc-99m & I-131 is = 0.879, which indicates strong correlation between them. So, it is statistically significant and makes a good agreement. The outcome of this study may provide valuable information about thyroid treatment and also may play important role in the management of thyroid patient.

Optical screening of hepatitis-B infected blood sera using optical technique and neural network classifier.

In this study we demonstrate the analysis of biochemical changes in the human blood sera infected with Hepatitis B virus (HBV) using Raman spectroscopy. In total, 120 diseased blood samples and 170 healthy blood samples, collected from Pakistan Atomic Energy Commission (PAEC) general hospital, were analyzed. Spectra from each sample of both groups were collected in the spectral range 400-1700 cm-1. Careful spectral analyses demonstrated significant spectral variations (p < 0.0001) in the HBV infected individuals as compared to the normal ones. The spectral variations presumably occur because of the variations in the concentration of important biomolecules. Variations in spectral signatures were further exploited by using a neural network classifier towards machine-assisted classification of the two groups. Evaluation metrics of the classifier showed the diagnostic accuracy of (0.993), sensitivity ( = 0.992), specificity ( = 0.994), positive predictive value ( = 0.992) and negative predictive value ( = 0.994). The observed variations in the molecular concentration may be important markers of the hepatic performance and can be used in the diagnosis and machine-assisted classification of HBV infection.

Kinetics of hydrogen desorption from Zircaloy-4: Experimental and modelling

Under Pressurized Water Reactor normal operating conditions, the external surface of zirconium alloys cladding absorbs a fraction of the hydrogen produced by water reduction. During spent fuel transport, hydrogen may desorb from the cladding. The study aims to identify and quantify the rate-limiting step in the hydrogen desorption process initially present in the alloy. To better understand this process, the Thermal Desorption Spectrometry (TDS) was used in association with X-ray Photoelectron Spectroscopy analysis. TDS results were analysed with finite elements simulations using the Cast3M code. The optimization of the kinetic constants of hydrogen desorption was performed with CEA (Alternative Energies and Atomic Energy Commission)-tool URANIE. Results showed that hydrogen desorption kinetics from the metal is limited by the surface molecular recombination. Arrhenius-type temperature dependence of kinetic constants allowed to simulate experimental data with a good agreement. The optimized activation energy and the pre-exponential factor for desorption processes were in the range of 290 ± 10 kJ mol−1 and 3 × 107 m4 mol−1 s−1 respectively.

Study of emission of radioactive gaseous effluents in the production of 18F-FDG

The number of units producing radiopharmaceuticals with a half-life of fewer than two hours has increased with the growth of PET technology in Brazil. In the production of such radiopharmaceuticals such as 18F-FDG or 11C-PIB, gaseous waste is formed. The International Atomic Energy Agency (IAEA) proposes a methodology that can be used to evaluate the dispersion of these gaseous effluents. This work has retrospectively evaluated the emission of radioactive gaseous effluents generated in the production of 18F-FDG, in order, to delimit yield values of radioactive waste in the gaseous form and to verify the effectiveness and the design of the safety elements of the exhaust system evaluated before the standards of the National Nuclear Energy Commission (CNEN) and IAEA recommendations. Thirty-six productions of 18F-FDG were found.

Mapping the Critical Intellectual Capital of IRD

Currently, several studies that dealing with the subject of knowledge management aiming the preservation and transfer of intellectual capital, leading to the retention of knowledge retention in an institution or organization. The National Nuclear Energy Commission (CNEN) of Brazil, the federal authority responsible for the national nuclear energy standards, research, development, and regulation, has been facing difficulties in human resources due to the increase in the number of retirements and the lack of replacement of people, especially with the scientific-technical profile, as a result of the cancelation of public employee hiring in the country.The purpose of this study is to map the critical technical areas at the Institute of Radiation Protection and Dosimetry (IRD), from CNEN. A model used by the International Atomic Energy Agency (IAEA) was adopted here, which takes into account the time for retirement, beyond the specificity and availability of knowledge.As a result of the study, it was possible to identify that in all end-areas, the IRD has employees that retain the critical knowledge, but they are hard to be replaced or transfer their knowledge. Therefore, a management plan should be implemented for the retention and transfer of knowledge specific to the nuclear area, which is essential for IRD to continue to meet its strategic objectives and that also contributes to minimize the impacts to the country generated by the loss of this sensitive and specialized knowledge.

Network Time Synchronization of the Readout Electronics for a New Radioactive Gas Detection System

In systems with multiple radiation detectors, time synchronization of the data collected from different detectors is essential to reconstruct multi-detector events such as scattering and coincidences. In cases where the number of detectors exceeds the readout channels in a single data acquisition electronics module, multiple modules have to be synchronized, which is traditionally accomplished by distributing clocks and triggers via dedicated connections. To eliminate this added cabling complexity in the case of a new radioactive gas detection system prototype under development at the French Atomic Energy Commission, we implemented time synchronization between multiple XIA Pixie-Net detector readout modules through the existing Ethernet network, based on the IEEE 1588 precision time protocol. The detector system is dedicated to the measurement of radioactive gases at low activity and consists of eight large silicon pixels and two NaI(Tl) detectors, instrumented with a total of three 4-channel Pixie-Net modules. Detecting NaI(Tl)/silicon coincidences will make it possible to identify each radioisotope present in the sample. To allow these identifications at low activities, the Pixie-Net modules must be synchronized to a precision well below the targeted coincidence window of 500-1000 ns. Being equipped with an Ethernet PHY compatible with IEEE 1588 and synchronous Ethernet that outputs a locally generated but system-wide synchronized clock, the Pixie-Net can operate its analog to digital converters and digital processing circuitry with that clock and match time stamps for captured data across the three modules. Depending on the network configuration and synchronization method, the implementation is capable to achieve timing precisions between 300 ns and 200 ps.