Nuclear and Radiological Regulatory Authority NRRA

Minyat an Naşr, Egypt

Nuclear and Radiological Regulatory Authority NRRA

Minyat an Naşr, Egypt
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Elhefnawy O.A.,Nuclear and Radiological Regulatory Authority NRRA | Elabd A.A.,Nuclear and Radiological Regulatory Authority NRRA
Radiochimica Acta | Year: 2017

The paper addresses the modifications of the most common mineral clay "kaolinite" for U(VI) removal from aqueous solutions. A new modified Egyptian natural kaolinite (Ca-MK) was prepared by coating kaolinite with calcium oxide. Another modification process was utilized by calcination and acid activation of kaolinite (E-MK). The Egyptian natural kaolinite (E-NK) and the two modified kaolinites were characterized by different techniques SEM, EDX, XRD, and FTIR. The removal process were investigated in batch experiments as a function of pH, contact time, initial U(VI) concentration, effect of temperature, and recovery of U(VI) were studied. The equilibrium stage was achieved after 60 min and the kinetic data was described well by pseudo-second order model. Isothermal data was better described by the Langmuir isotherm model, indicating the homogeneous removal process. Also the removal process was studied on different temperature 293, 313, and 323 K. The thermodynamic parameters ΔH°, ΔS°, and ΔG° were calculated. The thermodynamic results pointed to the endothermic and favorable nature of the U(VI) removal process in the three kaolinite adsorbents. This study indicated that (Ca-MK) has higher CEC and can be used as a new adsorbent for highly efficient removal of U(VI) from aqueous solutions. © 2017 Walter de Gruyter GmbH, Berlin/Boston.


Elabd A.A.,Nuclear and Radiological Regulatory Authority NRRA | Elhefnawy O.A.,Nuclear and Radiological Regulatory Authority NRRA | Badawy I.,Nuclear and Radiological Regulatory Authority NRRA
Annals of Nuclear Energy | Year: 2017

The nuclear and radiological regulatory body [RB] in a State is the official authority in that State to control nuclear materials [NMs] and other radioactive materials [RMs] and all nuclear facilities in that State. In such capacity the RB may use information about the quantity, type and characteristics of every and all NMs and RMs that may exist in nuclear and radiation facilities in the State, and the flow of such materials through those facilities inside or to outside the State. Elements of nuclear safeguards culture [SGC] would not replace these technical criteria. Rather, it would be aimed to raising awareness of nuclear safeguards [SG] requirements and functions, and strengthening technical capacity of staff to meet those requirements. This study proposes a definition and the task of SGC to the attention of national and international SG communities. The roles, responsibilities of various disciplines and organizations, and the public nuclear awareness could be enforced with SGC. This would improve the effectiveness and efficiency of SG implementation in the State. © 2017


Elabd A.A.,Nuclear and Radiological Regulatory Authority NRRA | Attia M.S.,University of Jeddah | Attia M.S.,Ain Shams University
Journal of Luminescence | Year: 2016

A new fluorescent optical sensor for highly sensitive and selective assessment of UO2 2+ in aqueous samples was introduced. The response of the sensor is based on the fluorescence quenching of [(+)-(S)-methyl 2-(2-chlorophenyl)-2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)acetate] (Clopidogrel) embedded in polymethylmethacrylate (PMMA) polymer by UO2 2+. The sensor displays; wide concentration range from 1.0×10-9 to 4.0×10-6 mol L-1, limit of detection (LOD) and limit of quantification (LOQ) are 2.6×10-10 and 7.8×10-10 mol L-1, respectively with a relatively fast response time of less than 60 s. The present sensor was revealed good response characteristics with respect to stability, reproducibility, sensitive and selectivity. Also, the response and quenching mechanisms for the present sensor were discussed. © 2015 Elsevier B.V.


Elabd A.A.,Nuclear and Radiological Regulatory Authority NRRA | Attia M.S.,University of Jeddah | Attia M.S.,Ain Shams University
Journal of Luminescence | Year: 2015

Abstract A new, simple and sensitive method for the assessment of UO22+ was developed. The method is based on the quenching of the fluorescence intensity of the thin film optical sensor 1-(2,3,4-trimethoxybenzyl) piperazine [Trimetazidine] doped in sol gel matrix in the presence of different UO22+ concentrations in DMSO. The remarkable quenching of the fluorescence intensity of Trimetazidine by various UO22+ concentrations was successfully used as a new optical sensor for the assessment of UO22+ in DMSO at λexem=340/374 (nm). The mechanism of the interaction between the optical sensor and UO22+ was discussed. The calibration plot was achieved over the concentration range 1.7 × 10-6-4.9 × 10-8 mol L-1 with a correlation coefficient of (0.999) and limit of detection (LOD) and limit of quantification (LOQ) are 4.1 × 10-8 and 1.2 × 10-7 mol L-1, respectively. © 2015 Elsevier B.V. All right sreserved.


Refeat R.M.,Nuclear and Radiological Regulatory Authority NRRA
Kerntechnik | Year: 2015

A tendency to increase the discharge burnup of nuclear fuel for Advanced Pressurized Water Reactors (PWR) has been a characteristic of its operation for many years. It will be able to burn at very high burnup of about 70 GWd/t with UO2 fuels. The U-235 enrichment must be higher than 5 %, which leads to the necessity of using an extremely efficient burnable poison like Gadolinium oxide. Using gadolinium isotope is significant due to its particular depletion behavior ("Onion-Skin" effect). In this paper, the MCNPX2.7 code is used to calculate the important neutronic parameters of the next generation fuels of PWR. K-infmity, local peaking factor and fission rate distributions are calculated for a PWR assembly which burn at very high burnup reaching 70 GWd/t. The calculations are performed using the recently released evaluated Gadolinium cross section data. The results obtained are close to those of a LWR next generation fuel benchmark problem. This demonstrates that the calculation scheme used is able to accurately model a PWR assembly that operates at high burnup values. © 2015 Carl Hanser Verlag GmbH & Co. KG.


Louis H.K.,Nuclear and Radiological Regulatory Authority NRRA
Kerntechnik | Year: 2014

Reactor kinetic parameters are very important for safety analysis in power reactors. This paper focused on calculations of kinetic parameters such as the effective delayed neutron fraction (ßeff), the neutron generation time (Λ) and the prompt neutron lifetime lp for PWR. In this paper the burn-up calculations were performed to calculate kinetic parameters as a function of burn-up for a PWR when fueled with standard UO2 fuel and MOX (Mixed-Oxide) fuel in order to study the impact of burn-up on these parameters. The calculations were performed using the Monte Carlo code MCNPX. The core chosen for the simulation is based on a 4-loop Westinghouse PWR power plant. The calculations were performed from beginning of the life to the end of life 210 days and compared with safety values taken from the design control document of an API000 PWR. The results are in agreement for UO2 but not for MOX until end of cycle (EOC).


Elabd A.A.,Nuclear and Radiological Regulatory Authority NRRA | Elhefnawy O.A.,Nuclear and Radiological Regulatory Authority NRRA | El Nahrawy A.M.,National Research Center of Egypt
RSC Advances | Year: 2016

A new organic-silica based nanocomposite has been prepared for uranyl ions (UO2 2+) determination based on the absorbance enhancement of tartrazine incorporated copper sodium silicate nanocomposites (T-CSS). T-CSS has been characterized by Fourier Transforms Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDX) and Transmission Electron Microscopy (TEM). The UO2 2+/T-CSS complex shows a maximum absorption at 252 nm with a molar absorptivity of 6.5 × 103 L mol-1 cm-1. Beer's law has been applied in the range of 2.0 × 10-5 to 1.5 × 10-4 mol L-1. For more accurate analysis, the Ringbom optimum concentration range was 2.1 × 10-5 to 1.3 × 10-4 mol L-1. Sandell sensitivity, detection and quantification limits have been calculated. Also, T-CSS was applied on the determination of UO2 2+ in real samples. The results have been compared with Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) data, and very similar values were found by the two methods. © 2016 The Royal Society of Chemistry.


A new "turn-off" fluorescent sensor for determination of thorium (Th(iv)) by thin film of 2-(acetyloxy)-N-(5-nitro-2-thiazolyl)-benzamide (L) embedded in sol-gel matrix was introduced. The high efficiency of quenching was caused by non-covalent binding of the positively charged Th(iv) to the negatively charged L. The quenching mechanism is discussed. Judging from temperature and UV-visible absorbance spectra, the quenching mechanism was proved to be static. The stoichiometry and binding ability of L during complexation with Th(iv) were estimated by Job's, Hill's and modified Benesi-Hildebrand plots. Under optimized conditions, a fluorescence quenched at λex/λem = 420/482 (nm) after 2 min, which was linearly related to the concentration of Th(iv) in the range of 3.0 × 10-8 to 1.0 × 10-6 mol L-1. By comparing with selected developed optical sensors, the present sensor exhibits remarkable advantages with satisfactory results that could be used as a tool in nuclear-safeguards material accountability measurements for Th(iv) determination as a "turn-off" fluorescent sensor. © 2016 The Royal Society of Chemistry.


Elabd A.A.,Nuclear and Radiological Regulatory Authority NRRA | Elhefnawy O.A.,Nuclear and Radiological Regulatory Authority NRRA
Journal of Fluorescence | Year: 2016

A new, simple and sensitive optical sensor for determination of uranyl ion (UO2 2+) in aqueous solutions by spectrofluorimetric technique was introduced. The fluorescence spectra and response characteristics of 4-chloro-2 (furan-2-ylmethylamino) - 5-sulfamoylbenzoic acid (Furosemide) to UO2 2+ was investigated. It showed preferable fluorescence response to UO2 2+. Thereby, an efficient and sensitive optical sensor based on the fluorescence enhancement of Furosemide as a new fluoroionophore for UO2 2+ determination at low concentration levels has been developed. The reaction was extremely rapid at room temperature, and the fluorescence intensity remains unchanged for at least 24 h. Also, the response mechanism of the present sensor is discussed. This optical sensor is useful owing to the sufficient capability for determination of UO2 2+ in various real samples. Apart from the high sensitivity, the procedure is very simple, fast, wider linear range and gains a low detection limit without any complicated equipment. The present sensor has been successfully tested for determination of UO2 2+ in real samples and the results obtained are comparable to inductively coupled plasma optical emission spectrometry (ICP-OES) measured which could be used as a promising tool in nuclear safeguards material accountability measurements. © 2015 Springer Science+Business Media New York.


PubMed | Nuclear and Radiological Regulatory Authority NRRA
Type: Journal Article | Journal: Journal of fluorescence | Year: 2016

A new, simple and sensitive optical sensor for determination of uranyl ion (UO2 (2+)) in aqueous solutions by spectrofluorimetric technique was introduced. The fluorescence spectra and response characteristics of 4-chloro-2 (furan-2-ylmethylamino) - 5-sulfamoylbenzoic acid (Furosemide) to UO2 (2+) was investigated. It showed preferable fluorescence response to UO2 (2+). Thereby, an efficient and sensitive optical sensor based on the fluorescence enhancement of Furosemide as a new fluoroionophore for UO2 (2+) determination at low concentration levels has been developed. The reaction was extremely rapid at room temperature, and the fluorescence intensity remains unchanged for at least 24h. Also, the response mechanism of the present sensor is discussed. This optical sensor is useful owing to the sufficient capability for determination of UO2 (2+) in various real samples. Apart from the high sensitivity, the procedure is very simple, fast, wider linear range and gains a low detection limit without any complicated equipment. The present sensor has been successfully tested for determination of UO2 (2+) in real samples and the results obtained are comparable to inductively coupled plasma optical emission spectrometry (ICP-OES) measured which could be used as a promising tool in nuclear safeguards material accountability measurements.

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