Algerian Journal of Engineering and Technology

Non-destructive multielement analysis of airborne particles by instrumental neutron activation analysis

Abderrahmane Ararem — 2024-03-09

Instrumental neutron activation analysis (INAA) was used for the determination of the elemental composition of aerosol samples. Two samples of air of approximately 20 m³ each one were collected of the atmosphere around the Es-Salam research reactor site in Algeria. The irradiation of the samples and reference materials was carried out during 30 s for the elements of short half-life and 06 h for the elements of medium and long half-life with a thermal neutrons flux of 1.12 10¹³ and 6.88 10¹³ n/cm²s respectively. Ge(Hp) g-spectrometry made it possible to determine fifteen elements (Al, Cl, Mn, Ca, Cd, Br, La, Fe, Nd, Ce, Hg, Cr, Hf, Sb and Zn). The obtained results for the used reference materials almost perfectly match its certified values (Z_score<2).

Study of the elaboration of U3O8 by the Modified Direct Denitration process (MDD)

Messaoud Bennemla — 2023-12-28

In the nuclear industry, uranium trioxide (UO₃) is considered an intermediate in the preparation of uranium metal or uranium dioxide (UO₂), which are the two most widely used nuclear fuels. Several processes have been described for transforming solutions of uranyl nitrate UO₂(NO₃)₂ into uranium trioxide. Among these processes, Modified Direct Denitration (MDD) has been implemented to prepare Uranium trioxide with high reactivity. This process consists of adding ammonium nitrate to a pure uranyl nitrate solution to form the double salt (NH₄)₂UO₂(NO₃)₄.2H₂O which decomposes by calcination to produce a UO₃ powder. The objective of this work is to study, first, the thermal decomposition of double salt (NH₄)₂UO₂(NO₃)4.2H₂O in nitrogen atmosphere by thermogravimetry in order to determine the formation temperatures of the different phases and second, the determination of the optimal parameters (time and temperature) to prepare stable triuranium octoxide (U₃O₈) using muffle furnace. As results, the MDD product obtained is an orange colored and free flowing UO₃ powder, having a surface area in the target range [5-12 m²/g]. In addition, by calcination of UO₃ powder at 650°C for one hour, U₃O₈ oxide is obtained. The identification of the latter by the O/U ratio gave a value of 2.65, which is in the range [2.6-2.66]. This suggests that the oxide produced under these conditions is β-U₃O₈.

Contribution to characterization of the Zinc retention by marl collected from the aquifer substratum

Mourad Bellaloui — 2023-12-28

Two samples (S20 and S6) of marl are collected from aquifer substratum of the watershed of Wadi El-Ghoula in order to make a comparative study to remove Zinc from solution. The DRX analysis indicate five phases Montmorillonite, Illite, Kaolinite, Calcite and Quartz X-Fluorescence shows the predominance of silica, alumina and lime. In FTIR analysis, all bands are identified for S20, S6. The specific surface area for S20 and S6 are equal respectively to 21.6206 m²/g and 24.6445 m²/g and our materials have a meso-porous character. The retention capacity at equilibrium for S20 and S6 are equal respectively to 9.94 (mg/g) and 9.87 (mg/g). Liquid film diffusion and intraparticle diffusion models control simultaneously the process of adsorption of zinc in Marl. Non-linear treatment gives Langmuir and Temkin as best model for S20 and Freundlich for S6. Radlish-Peterson is the best model for S20 but for S6 the best model is given simultaneously by Sips and Radlish-Peterson. The values of AIC and AICc give a good opportunity to separate between used isotherms models.

Gamma spectrometry technique application to the 60Co sorption onto IRN-77 resin from radioactive wastewater: Equilibrium, Kinetic and Thermodynamic investigations

Souad Achour — 2023-12-28

The performance of synthetic ion exchange resin IRN-77 have been studied in this work in order to use it as an adsorbent to remove radioactive isotope 60Co from nuclear wastewater by the sorption process, using the gamma spectrometry technique. The resin simple was identified using SEM and FTIR infrared spectrometry. The gamma radiation acquisition emitted from the fixed radioactive ⁶⁰Co onto IRN-77 solid samples was carried out using the gamma spectrometry chain, equipped with an HPGe semi-conductor detector with high-resolution. Various factors were considered for the sorption process study such as ⁶⁰Co concentration, contact time and temperature. The maximum adsorption capacity of the IRN-77 samples was determined by studying the adsorption isotherms; Kinetics models including thermodynamics were also studied and investigated. The experimental results showed that the adsorption reaction was adjustable to the pseudo-first-order and the Langmuir model was found to describe best the experimental results by obtaining a very important maximum adsorption quantity of 10.620 µCi of ⁶⁰Co per 1 gram of IRN-77 adsorbent. A dimensionless separation factor R_L was used to judge the favorable adsorption. The adsorption capacity of ⁶⁰Co ions onto IRN-77 particles increased with the increasing of temperature. The values of the thermodynamic parameters have shown that the ⁶⁰Co ions adsorption process was endothermic and favored at high temperatures with a positive value of the enthalpy ∆H° of 23,54 kJ/mol. The free energy’s values ∆G◦ are positive over the whole temperature range. The specific activities of the fixed ⁶⁰Co radionuclide allow evaluating the solid samples IRN-77 resin's sorption capacity.

An overview of the relative neutron activation analysis performed in the NAA Laboratory of the CRND using NUR reactor

Zohra Bouhila — 2023-12-28

Neutron activation analysis is a highly sensitive method for multi-elemental analysis, primarily focusing on the induced radioactivity in atomic nuclei rather than the inherent chemical and physical properties of samples. This approach requires exposing the sample to neutron irradiation, typically conducted within a nuclear reactor. One of the most successful applications of Instrumental Neutron Activation Analysis (INAA) in the vicinity of the NUR reactor pertains to its use in environmental studies. It facilitates the monitoring of the distribution of trace elements (TEs) and the attribution of emission sources by analyzing samples from diverse environmental sources, including soil, air, and bioaccumulative plants collected from various locations near Algiers, Algeria. Since 2010, our laboratory has actively engaged in proficiency tests with WEPAL/IAEA, which has been instrumental in advancing and refining the methods of Neutron Activation Analysis (NAA) employed in this domain. The outcomes derived from these environmental investigations substantiate the presence of more than 30 trace elements. Comparing the enrichment factors (FEs) reveals the contribution of anthropogenic pollution, such as vehicles emitting Sb, Se, and Zn, brickyards releasing As, Co, Cr, Fe, Na, Se, Sc, Ta, and Tb, as well as soil resuspension leading to the release of Br and Zn. Additionally, our laboratory has conducted further studies in the realm of biology using the relative approach of NAA. The primary objective has been to harness the potential of NAA for early diagnosis in cases of cancer and chronic diseases. Consequently, we've examined the trace element composition in the whole blood of both healthy individuals and those afflicted by illnesses. We achieved this by subjecting lyophilized blood samples from adult subjects to simultaneous irradiation alongside an A13-IAEA blood standard. The elemental concentrations were subsequently calculated by measuring gamma rays using a gamma spectrometer. We simultaneously determines the concentrations of ten elements: Rb, Fe, Zn, Na, K, Br, Se, Sr, As and Sc.