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The electronic stopping powers of LR-115 and Kapton polymeric foilshave been estimated, using Monte Carlo simulations, for 9 Be, 11 B, 12 C, 14 N, 16 O, and 35 Cl ions covering the energy range ~ 0.1-1.0 MeV/n. Comparison of stopping power based on Lindhard, Scharff, and Schiott (LSS) theory with the corresponding values obtained by SRIM and MSTAR codes in LR-115 and Kapton polymeric foils illustrate a significantly large deviations. However, a semiempirical equation has been proposed here and tested for better stopping power calculations at low-energy regime in the domain of LSS theory for Z = 4-8 ions across materials. Furthermore, the electronic energy losses for 9 Be and 16 O ions in SiO 2 and Al 2 O 3 , respectively, have been calculated in the energy range of ~ 0.1-1.0 MeV/n. The calculated stopping powers exhibit up to 10 % deviation from the experimental values and MSTAR data.

The aim of this work is to help inform the decision for choosing a convenient material for the PGAA (Prompt Gamma Analysis Activation) collimator plug to be installed at the tangential channel of the Moroccan Triga Mark II Research Reactor. Two families of materials are usually used for collimator construction: a mixture of high-density polyethylene (HDPE) with boron, which is commonly used to moderate and absorb neutrons, and heavy materials, either for gamma absorption or for fast neutron absorption. An investigation of two different collimator designs was performed using N-Particle Monte Carlo MCNP6.2 code with the ENDF/B-VII.1 and MCLIP84 libraries. For each design, carbon steel and lead materials were used separately as collimator heavy materials. The performed study focused on both the impact on neutron beam quality and the neutron–gamma background at the exit of the collimator beam tube. An analysis and assessment of the principal findings is presented in this paper, as well as recommendations.

The TRIGA Mark II research reactor is equipped with four horizontal beam tubes and one thermal column. The tangential (NB1) and Percy (NB2) beam tube, which are the subject of this study, are dedicated to Prompt Gamma Neutron Activation Analysis and Neutron Imaging, and (Neutron Diffraction) facilities, respectively. A preliminary neutron characterization is needed for each beam tube. Basic beam parameters, including neutron flux, were measured with threshold activation detectors for the two beam tubes (NB1, NB2). Activity measurement through gamma spectrometry was performed with a high-purity germanium detector to evaluate the neutron flux through multiple analyses of activation detectors. The results were compared with those obtained using an approximated Monte Carlo simulation model for the reactor. A comparison between the experimental and simulated results revealed a good level of agreement.

Radiological characterization of radionuclides contained in the phosphate rocks, phosphogypsum, phosphoric acid, and phosphates fertilizers (DAP, NPS, NPK, TSP, and TAP) in Morocco have been performed to provide a database for the assessment of the environmental and the radiological impacts. The measurements of the activity concentration were carried out using both alpha and gamma spectrometry. Additionally, the radiological parameters such as the gamma radiation hazard index, the internal and external hazard index as well as the outdoor and indoor absorbed gamma dose rates. The corresponding annual effective dose rates and the total excess lifetime cancer risk (ELCR) were also estimated to discuss the radiological hazard. The primary results showed that the activity concentrations of 238U, 234U, and 235U were 174.58–2604.14, 143.03–2765.34 and 8.35–131.64 Bq kg−1, respectively. The 230Th, 232Th and 234Th concentrations found were 239.29–1656.36, 0.68–17.71 and 133.54–2194.27 Bq kg−1, respectively. The specific activities of 226Ra and 40K ranged from

The Prompt Gamma Neutron Activation Analysis (PGAA) facility will be commissioned at the NB1 beam tube of the Moroccan TRIGA MARK II research reactor. PGAA is a non-destructive analytical technique used for multi-elemental analysis and especially for light element analysis. For better performances, PGAA requires small and focused beam, and high Фth/Фep and Фth/Фfast ratios, and low background gamma radiation. For this purpose, fast neutron filters are commonly used to reduce fast and epithermal components of neutron flux. In this paper, the impact of sapphire filter, introduced, within the collimator hole, at the beam port on neutron spectra was evaluated. Monte Carlo, MCNP6.2, code has been used with ENDF VII.1 neutron cross section library to perform this study. An approximate TRIGA MARK II reactor MCNP model has been used to generate neutron spectra at the entrance of the collimator. Then an independent model for both collimator and sapphire filter has been brought into calculation to fulfil our purpose. Results showed an increase of about 8 times for both Фth/Фep and Фth/Фfast ratios using a 10 cm length of sapphire.

The stopping power of Formvar and Mylar polymeric materials for energy region (0.1 to 1.0) MeV/nucleon 19F, 23Na, 24Mg, 27Al, 28Si, 31P, 32S, 35Cl, and 40Ar ions have been determined. The energy lo...

Many commercially available software packages have been created to analyze gamma-ray spectra, but their source code has generally not been shared, although some users may wish to add or modify certain functionality, which is impossible without access to the source code. This study therefore presents a new open-source software package for the analysis of gamma-ray spectra. The name of the software is GSA (Gamma-ray Spectra Analysis), the source code of which is freely available through the GitHub website (https://github.com/LAHCEN-EL-AMRI/Gamma-Spectra-Analysis). The main function of this initial version of the software is to locate peaks, calculate areas, and identify corresponding radionuclides. A future version will complement this by measuring the concentrations of radionuclide elements. The software was validated by comparing its analysis results with those generated by three other software programs, namely Genie 2000, Maestro, and FitzPeaks. All the formulas used are explained in this work, which could be useful for researchers or students looking to create their own software packages for analyzing gamma-ray spectra.

The Moroccan TRIGA Mark II research reactor is to be equipped with a PGAA (Prompt Gamma Activation Analysis) facility to assist the country's progression in socioeconomic areas such as the environment and geochemistry, agriculture, health, industry, cultural heritage, and human sciences. The requirements of the PGAA facility include a very high thermal to fast neutron flux ratio and a focused, thin beam. Supermirror neutron guides are generally used to meet such requirements due to their ability to reflect neutrons with a specific energy and scattering angle. This study was undertaken to determine a suitable neutron guide for achieving optimal performance for the PGAA facility, where such a determination needs to be made according to both the available space and the minimum performance needed for PGAA analysis. To better parameterize the neutron guide, a set of simulations were performed with the aim of establishing the best guide specifications. Three types of neutron guides were studied, namely straight, curved, and bender. McStas code was used in this study, and the simulations showed that the guides must be 6 m long and that the coating value m must be equal to 5 for the bender and straight guides and 6 for the curved guide. Among the three guide types, the thermal/epithermal (Фth/Фep) and thermal/fast (Фth/Фfast) ratios were found to be much better when using the curved guide.

The paper is an attempt, based on the IAEA’s Nuclear Security Series (NSS), to identify any unacceptable dysfunction of Physical Protection System (PPS) of the Material Test Reactor (MTR) facility in a Hypothetical Atomic Research Institute (HARI). The evaluation of an existing or a proposed PPS requires a methodical approach whereby the ability of the security system to meet defined protection goals as the safeguard against possibility of sabotage and theft should be measured. Without such kind of careful assessment, the PPS might waste valuable resources on unnecessary protection or, worse yet, fail to provide adequate protection at critical points of the facility. In this work, an assessment of the PPS weaknesses for a hypothetical facility against malicious acts is presented. Hence, those weaknesses are founded during the examination of the site to build a 3D computerized simulation to simulate force engagement to evaluate the physical protection system effectiveness. Based on the IAEA nuclear security series publications, the paper proposes a new layout to correct the vulnerabilities, and another analysis of the changes made for the MTR wall thicknesses access control and the redesigned building plan.

The aim of this study was to investigate the impact of heterogeneity on the dose calculation for two algorithms implemented in the TPS “Analytical Anisotropic Algorithm (AAA) and Acuros XB” and validated the use of Acuros XB algorithm in clinical routine. First, we compare the dose calculated by these algorithms and the dose measured at the given point P, which is found after heterogeneity insert. Second, we extend our work on clinical cases that present a complex heterogeneity. By evaluating the impact of the choice of the algorithm on the dose coverage of the tumor, and the dose received by the organs at risk for 20 patients affected by lung cancer. The result of our phantom study showed a good agreement with several studies that showed the superiority of the Acuros XB over the AAA in predicting dose when it concerns heterogeneous media. The treatment plans for 20 lung cancers were calculated by two algorithms AAA and Acuros XB, the results show a statistical significant difference between algorithms for Homogeneity Index and the maximum dose of planning target volume (HI: 0.11±0.01 vs 0.05±0.01 p = 0.04; Dmax: 69.30±3.12 vs 68.51±2.64 p = 0.02). Instead, no statistically significant difference was observed for conformity index CI and mean dose (CI: 0.98±0.18 vs 0.99±0.14 p = 0.33; Dmean: 66.3±0.65 vs 66.10 ±0.61 p = 0.54). For organs at risk, the maximum dose for spinal cord, mean dose and D37 % of lung minus GTV (dose receiving 37% of lung volume) were found to be lower for AAA plans than Acuros XB and the differences were statistically significant (p The use of the AXB algorithm is suitable in the case of presence of heterogeneity, because it allows to have a better accuracy close to the Monte Carlo calculation.

High-temperature gas-cooled reactors (HTGRs) are one of the promising candidates for the next generation of nuclear reactors due to their inherently and passively safe in normal operation and even under accident conditions. There are two HTGR concepts, one based on a pebble-bed core, and the other is a prismatic core. One of the key differences between the pebble-bed core and the prismatic core is the complexity of applying the seed-blanket (SB) concept to the internal production of U-233 from Th-232 in order to extend the cycle length of the reactor. Actually, an enhancement of the operating cycle length in the pebble-bed reactors fuelled with (Th,233U)O2 can be reached by using high U-233 ratios, but these ratios could result in high excess reactivity at the beginning of life (BOL). In order to suppress the excess reactivity phenomenon at the early stage of the fuel cycle, to flatten the reactivity curve as a function of time, a new reactivity control method has been investigated by incorporating burnable absorbers into the fuel particles. This purpose is set up by introducing two varieties of BAs, including Gadolinia and Erbia, either as a homogeneous mixture with the fuel kernel in the TRISO particles or as an additional layer next to the fuel kernel producing the quadruple isotropic (QUADRISO) particles. The present work aims at characterizing the effect of these different loading patterns on some neutronic parameters that define the reactor core under BOL conditions as well as during burnup. In this attempt, the nominal UO2 (17 wt% U-235) fuelled core was used as a reference, while the other models adopt (Th,233U)O2 (17 wt% U-233) fuel with Gadolinia and/or Erbia with different loading patterns. The calculation results show that excess reactivity can be compensated during the early stages of core life and flattened during the cycle by adding Erbia doped with a few ppm of Gadolinia to the TRISO/QUADRISO particles. In these updated configurations, the new core life achieved is approximately 678 Effective Full Power Days (EFPDs), equivalent to 52.5 GWd/t on a single-batch discharge burnup. This means that from the core fuelled with UO2, which has a core life of 537 EFPDs (37 GWd/ton), an average period of 141 EFPDs is extended.

Argan nutshells, available in Morocco as a low-cost by-product from Argan oil production, were used to produce a sawdust biosorbent for the extraction of U and other heavy metals (Cd, As, Zn, Cu, Ni and Cr) from merchant-grade phosphoric acid (PA). Packed column (D = 20 mm, L = 250 mm, flowrate 1 mL/min) lab-scale experiments were carried out with three different solutions: (1) a synthetic heavy metals solution, (2) pure PA at different concentrations (0.85%, 8.5% and 85%) in water, and (3) merchant-grade PA from an industrial fertilizer plant in Morocco that was diluted with water to analyze different P2O5 contents (5%, 30% and 54%) and a U concentration of up to 157 ppm. The sawdust successfully adsorbed 99% of the U from (1) the synthetic solution and (2) the pure PA independent of the acid concentration. It further managed to adsorb more than half (54%) of U, 75% of Cd, 74% of As, 84% of Zn, 86% of Cu, 83% of Cr of the merchant-grade PA at 54% P2O5 content and a flow-rate of 1 mL/min. The sawdust was characterized by SEM and FTIR to understand the adsorption of metal ions. Column studies were carried out to know the breakthrough point. At breakthrough, the effluent volume was found to be 50 mL and the maximum adsorption capacity for U was found to be 0.93 mg/g. Heavy metal recovery using ANS does not seem to be promising as a result of the low (>10%) desorption rates if citric- or oxalic acid is used as was done in this study. Heavy metal extraction without direct recovery using ANS is promising and should further be investigated though.