•Introducing PaO2 and NpO2 as novel burnable absorbers in (Th-233U-235U)O2 fuel assemblies for pressurized water reactors.•PaO2 and NpO2 showcased potential as novel burnable absorbers, reducing ...initial reactivity excess in (Th-233U−235U)O2 fuel assemblies.•Efficient transmutation of Pa-231 and Np-237 to fissile isotopes.•Introducing PaO2 and NpO2 positively enchance fuel and moderator temperature coefficients, enhancing overall safety.
Various advanced fuels and burnable absorbers (BAs) have been proposed to improve the cycle burnup of a pressurized water reactor (PWR) fuel assembly (FA). This study looks into the impact of an innovative fuel known as (Th-233U-235U)O2 with a novel neutron absorber with double coatings of PaO2 and NpO2. The study focuses on adding the proposed two-layer absorbers in some (Th-233U-235U)O2 fuel in an AP1000 assembly. Neutronic parameters such as burnup behavior, discharge burnup, and cycle length are calculated. The evolution of fuel composition in terms of actinides and fission products, as well as the variation in radioactivity with burnup, is investigated and compared to all-UO2 assembly as well as a UO2 assembly with 28 IFBA fuel rods containing 2 wt% Gd2O3. Additionally, primary safety parameters such as the fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC) are evaluated to determine the effectiveness of the proposed BAs in improving the drawbacks of (Th-233U-235U)O2 fuel, particularly MTC. The results are promising, with higher discharge burnups with increased Pa-231 and Np-237 transmutation for the most proposed designs compared to all-UO2 assembly. The recommended BAs also help to reduce reactivity swings. Furthermore, coatings with (Th-233U-235U)O2 PaO2 and NpO2 produce more negative values for FTC and MTC, implying better controllability.
This study investigates the performance and safety characteristics of (Th-233U-235U)O2 fuel in various cladding materials, including SiC and a sandwich cladding system combining SiC with SS-310, in ...comparison to traditional UO2 fuel with Zirlo™ cladding. Utilizing a dual-cooled annular assembly design, the (Th-233U-235U)O2 fuel demonstrates significant enhancements in cycle length, outperforming conventional UO2 assemblies. The radial power distribution analysis reveals that (Th-233U-235U)O2 fuel reduces maximum radial power, contributing to uniform power distribution and enhanced reactor safety. Reactivity feedback coefficients, including Fuel Temperature Coefficients (FTCs) and Moderator Temperature Coefficients (MTCs), are consistently negative for (Th-233U-235U)O2 fuel with advanced claddings, indicating improved inherent safety.
Background: In addition to the inherent challenges of their condition, children with autism spectrum disorder (ASD) are also susceptible to the global obesity epidemic. However, concerning the ...prevalence of obesity within the Moroccan ASD pediatric population, data remain scarce. Methods: A total of 258 children (boys = 195) aged 6 to 12 years old (mean = 9.4 ± 1.4) diagnosed with ASD participated in this study. Besides the body mass and height, four significant anthropometric markers for assessing obesity were examined: body mass index (BMI), body surface area (BSA), waist circumference (WC), and waist-to-height ratio (WHtR). Each anthropometric marker was categorized into one of three cardiometabolic risk levels based on the Z-scores and their corresponding percentiles. The distribution was as follows: low risk (≤84th percentile), high risk (85th–94th percentile), and very high risk (≥95th percentile). Subsequently, a multiple regression analysis was employed to develop an algorithm that generates a composite risk score. This score incorporates all the anthropometric variables simultaneously, while also weighting their individual contributions to the cardiometabolic risk. Results: Children with ASD exhibit an anthropometric profile that markedly increases their susceptibility to cardiometabolic issues. While roughly 11% of the general Moroccan child population is overweight or obese, this figure soars to nearly 60% among children with ASD when considering the central adiposity markers. Furthermore, children from middle-class socioeconomic backgrounds display a more than threefold greater risk of developing overweight or obesity compared to their counterparts from lower socioeconomic backgrounds. Conclusions: This study has, for the first time, provided an up-to-date overview of the cardiometabolic risk in Moroccan children with ASD using traditional anthropometric measurements. The primary risk factor is clearly linked to central (abdominal) adiposity, which is recognized as the most deleterious. This study highlights the need to include general and central obesity markers. This study underscores the importance of incorporating both general and central adiposity markers for a more comprehensive assessment, and it emphasizes the need for closer monitoring within this high-risk population.
This study's objective was to evaluate the depth profiles of rare earth elements (REEs) in two Pb-210 dated sediments cores retrieved from the Oualidia lagoon, reconstruct their anthropogenic ...history, and assess their potential ecological risk. The sediment cores analysis was carried out using instrumental neutron activation analysis. Other physical-chemical parameters (bulk, organic matter, grain size) were also measured. The results indicated that the highest values were recorded in the topmost layers of the sediment cores and depleted with depth. The historical records of REEs revealed an exponential increase in their concentrations from the 50s. The enrichment factor, geo-accumulation index, and contamination factor calculated for each sediment core layer have exhibited important concentrations of Gd, Sm, and Eu, suggesting an anthropogenic origin of detected elements. Based on ecological risk >40 and the risk index >220, Gd, Eu, and Sm pose a high risk on the study area, while the other elements present moderate and mild risk. The obtained results revealed an increasing tendency of REEs accumulation into the Oualidia lagoon and suggested that a new source is feeding the lagoon sediments by these elements. These findings provided a clear picture of REEs evolution between 1903 and 2014 and baseline information on the historical deposition of these elements in the Oualidia lagoon.
Water quality preservation represents one of the biggest challenges the world is facing nowadays. In Morocco, water quality decline is among the significant problems facing the country’s water ...sector. Geographic Information System (GIS) is an effective and useful tool for interpreting, evaluating and displaying spatial data for water resources management. In order to assess the Physico-chemical characteristics of groundwater of the Sahel-Doukkala aquifers, water samples were collected from 50 points well distributed in the study area, analysed according to standard methods, and the results were interpreted using the geographic information system (GIS) technique. There was an important spatial variability in the studied parameters and element concentrations (T°, pH, EC, Cl
-
, Ca
2+
, Mg
2+
, Sr, B and Na
+
), revealing that the aquifers lithology, sea intrusion and the agriculture methods are the main factors influencing the water nature in the study area.
An essential step in evaluating and comparing the performance of two passive radiation dosimeter types, thermosluminescent (TLD) and optically stimulated luminescence (OSL), used by workers in ...environments with ionizing radiation for individual radiological monitoring and control of external exposure at various times (cumulative dose for 1 month), is to compare the measured dose accuracy, energy response, and coefficient of variation.
In fact this performance study consists in determining the accuracy of both R(10) and R(0.07) which are considered as the ratios of the measured dose (Hp(10) or Hp(0.07)) to the delivered dose (Hp(10) or Hp(0.07)) for each photon energy. The validity of the results of this test is based on the acceptance limits of the ICRP and the international standard IEC-62387. The relative energy response used is normalized to the 137Cs 662 keV energy to find which energy response is closest to the ideal case, and the coefficient of variation that allows to determine the statistical fluctuation of the Hp(10) and Hp(0.07) doses.
The results of the accuracy test for the OSL and TLD dosimeters are acceptable because they fall within the ICRP limits. For the energy response, the OSL performs better than the TLD for Hp(10) and Hp(0.07), and for the coefficient of variation, the OSL satisfies the requirements of ISO 62387 for both Hp(10) and Hp(0.07), while the TLD satisfies these requirements only for the measurement of Hp (0.07).
Quality control of dose calibrators is essential to evaluate the accuracy of the instrument response. In this work, a GUI (Graphical User Interface) has been developed to facilitate performing and ...recording quality control tests of dose calibrators. The interface is capable to automate several tests which include routine checks, accuracy test, linearity test, reproducibility test, repeatability test, concordance MBq/mCi test, and geometry test. In principle, the program computes correction factors that should be applied to minimize the uncertainty of measurements and the determining factors for success or failure of each test, then visualizes the results as tables and curves into a pdf file. Therefore, this interface can be considered as an efficient tool for performing quality control tests of dose calibrators thought it is still unable to offer the correction factors for the geometry test without experiment which will be achieved by integrating Monte Carlo simulation into the GUI.
Covid-19 was first reported in Morocco on March 2, 2020. Since then, to prevent its propagation, the Moroccan government declared a state of health emergency. A set of rapid and strict ...countermeasures have taken, including locking down cities, limiting population's mobility and prohibiting almost all avoidable activities. In the present study, we attempted to evaluate the changes in levels of some air pollutants (mainly PM10, NO2 and SO2) in Salé city (North-Western Morocco) during the lockdown measures. In this context, a continuous measurement of PM10, SO2 and NO2 was carried before and during the Covid-19 lockdown period. As a consequence of the security measures and control actions undertaken, the emissions from vehicle exhaust and industrial production were significantly reduced, which contribute to the decrease in the concentrations of the studied pollutants. The obtained results showed that the difference between the concentrations recorded before and during the lockdown period were respectively 75%, 49% and 96% for PM10, SO2 and NO2. PM10 levels were much less reduced than NO2. The three-dimensional air mass backward trajectories, using the HYSPLIT model, demonstrated the benefits of PM10 local emission reductions related to the lockdown were overwhelmed by the contribution of long-range transported aerosols outside areas. In addition, noteworthy differences in the air mass back trajectories and the meteorology between these two periods were evidenced.
Daily average concentrations of SO2 and NO2 from March 11th to April 2nd in Salé city. Display omitted
•PM10, NO2 and SO2 concentrations were reduced by more than half during the covid-19 lockdown period.•Covid-19 countermeasures contribute to reduce all pollutant concentrations but with significant differences among them.•Long-range transported aerosols contributions overcame the PM10 local emission reductions benefits related to the lockdown.
Covid-19 was first reported in Morocco on March 2, 2020. Since then, to prevent its propagation, the Moroccan government declared a state of health emergency. A set of rapid and strict ...countermeasures have taken, including locking down cities, limiting population's mobility and prohibiting almost all avoidable activities. In the present study, we attempted to evaluate the changes in levels of some air pollutants (mainly PM
, NO
and SO
) in Salé city (North-Western Morocco) during the lockdown measures. In this context, a continuous measurement of PM
, SO
and NO
was carried before and during the Covid-19 lockdown period. As a consequence of the security measures and control actions undertaken, the emissions from vehicle exhaust and industrial production were significantly reduced, which contribute to the decrease in the concentrations of the studied pollutants. The obtained results showed that the difference between the concentrations recorded before and during the lockdown period were respectively 75%, 49% and 96% for PM
, SO
and NO
. PM
levels were much less reduced than NO
. The three-dimensional air mass backward trajectories, using the HYSPLIT model, demonstrated the benefits of PM
local emission reductions related to the lockdown were overwhelmed by the contribution of long-range transported aerosols outside areas. In addition, noteworthy differences in the air mass back trajectories and the meteorology between these two periods were evidenced.
This article investigates alternate fuel options for Pressurized Water Reactors (PWRs), focusing on thorium use to address safety, efficiency, and waste issues associated with standard UO 2 fuel. ...Challenges in thorium utilization, such as the lack of a fissile isotope, are handled using approaches such as homogeneous mixtures and heterogeneous arrangements, promoting the exploration of (Th- 233 U- 235 U)O 2 fuel in various assembly configurations. According to recent research, the annular dual-cooled assembly design has promising results in terms of fuel efficiency and safety while lowering the requirement for higher fissile enrichment levels. Studies additionally demonstrate that annular dual-cooled duplex fuel configurations can produce higher discharge burnup and lower power peaking factors than traditional UO 2 fuel. The purpose of this work is to analyze and compare the performance of (Th- 233 U- 235 U)O 2 fuel in various configurations against conventional UO 2 fuel, focusing on key characteristics such as reactivity change, criticality, discharge burnups, and reactivity feedback coefficients.
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