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Open access

Marcin Rogowski, Tomasz Smoliński, Marta Pyszynska, Marcin Brykała and Andrzej G. Chmielewski

Abstract

The use of radiotracers in the present study is intended to replace traditional steps of metal quantitative analysis (solution sampling and instrumental chemical analysis) and to allow real-time measurements of metal concentrations during the leaching process. In this study, 64Cu, an isotope of copper, was selected as a radiotracer. Samples of copper flotation tailings were irradiated in the Maria research reactor (Świerk, Poland) and mixed with an inactive portion of the milled fl otation waste. The leaching process was carried out in a glass reactor, and the radiation spectrum was measured using a gamma spectrometer. The material was then treated using various acids (sulphuric acid, nitric acid, acetic acid, citric acid, and ascorbic acid) in a wide range of their concentrations. Experiments with the radiotracer were conducted in sulphuric and nitric acids. The amount of the leached metal (copper) was calculated on the basis of the peak area ratio in the gamma-ray spectrum of the activated tailings and standard samples. Inductively coupled plasma mass spectrometry (ICP-MS) was also used to analyse the metal content. Maximum recovery of 56% Cu was achieved using 9 M HNO3, whereas the recovery was lowest for ascorbic acid (<1%). Both analytical methods were compared, and the results presented in this paper are in good agreement with radiometric measurements obtained using ICP-MS analysis.

Open access

Tomasz Smoliński, Marcin Rogowski, Marcin Brykała, Marta Pyszynska and Andrzej G. Chmielewski

Abstract

Scientifi c objective of this work was elaboration of radiometric method for the development of hydrometallurgical process for recovery of Cu from the copper ore. A neutron activation analysis (NAA) was identifi ed as a very convenient tool for the process investigation. The samples of copper ore were activated in a nuclear reactor. The parameters of the neutron activation were calculated. Radioisotope 64Cu was selected as an optimal tracer, and it was used for the investigation of the leaching process. During the experiments, various processes applying leaching media such as sulphuric acid, nitric acid, and organic acids were investigated. The recovery of the metals using sulphuric acid was insuffi cient, around 10%. Investigated organic media also did not meet expectations. The best results were obtained in experiments with nitric acid. Up to 90% of Cu and other metals were extracted from the copper ore. Copper concentration calculations obtained by NAA were confi rmed by inductively coupled plasma mass spectrometry (ICP-MS) technique. Both techniques gave comparable results, but the advantage of the NAA is a possibility for easy online measurements without shutting down or disturbing the system.

Open access

Nan Gan, Kuang Cen, Rong Ye and Ting Li

Abstract

The surveys of terrestrial gamma dose rate, radon concentration indoor and in water and specific activity of radionuclides of soil were carried out in 14 villages and a town in Xiangshan uranium deposit and surrounding area, Jiangxi province, Eastern China, in 2017-2018, using a scintillator dosemeter, an ionization chamber and a high-purity germanium gamma spectrometer to study radiation status in these places after remediation. A radioactive hot spot was discovered in a village near the mining office, where specific activity of 238U, 226Ra, 232Th and 137Cs of soil was as high as 1433 ± 76 Bq/kg, 1210 ± 62 Bq/kg, 236 ± 13 Bq/kg and 17 ± 1.1 Bq/kg, respectively. The dose rate on a waste rock heap was about 2423 nGy/h. Approximately 50% of the houses in a village near the uranium mining site had radon concentrations that exceeded 160 Bq/m3. There was a significant positive correlation between indoor radon concentration and outdoor gamma dose rate (R2 = 0.7876). The abnormal radon concentration was observed in a rising spring sample providing residents with tap water up to 127.1 Bq/l. Four tap water samples and three of five well water samples exceeded the limit of radon concentration of drinking water in China (11.1 Bq/l). The mean annual effective doses from gamma dose rate data were 0.86 mSv/y and 1.13 mSv/y for indoor radon. The study shows that there are some radioactively contaminated places surrounding the Xiangshan uranium mine. The local outdoor dose rate averages may be used to estimate local indoor radon concentrations.

Open access

Marcin Stobiński, Filip Jędrzejek and Barbara Kubica

Abstract

The aim of the research is to obtain preliminary information about the spatial distribution of gamma radionuclides in the soils taken from the Ojców National Park with emphasis on the behaviour of artificial radionuclides, with 137Cs as a representative. The natural radionuclides 40K, 226Ra (uranium series), and 228Th (thorium series), which are considered as background radiation, were also determined. In total, 18 soil samples were collected during the summer periods in 2015-2017, while the sampling points were selected with respect to differences in rainfall and local topography gradient. The method was based on gamma-ray spectrometry performed on high-purity germanium (HPGe) gamma detector (relative efficiency 34%). 137Cs was mostly deposited in the top soil layers, with activity in the range of 27.9÷586.6 Bq·kg-1. We found strong positive correlation of the 137Cs activity with the soil organic matter content, and at the same time, its dependence on the rainfall amount. Consequently, the soil types and local climate can control the spatial distribution of 137Cs on a small spatial scale. The quantity of natural radionuclides was highly similar in all samples with the following mean values: 38.0 Bq·kg-1for 228Th, 33.1 Bq·kg-1for 226Ra, and 479.9 Bq·kg-1for 40K.

Open access

Marta Adamczyk, Sebastian Adamczyk and Tomasz Piotrowski

Abstract

Background and objectives: To justify the concept of validating conformal versus intensity-modulated approach in the treatment of non-small cell lung cancer (NSCLC). Materials and methods: For 10 patients representative of the spectrum of tumour sizes and locations, two plans were prepared: one with three-dimensional conformal radiation therapy (3DCRT) technique and the other with intensity-modulated radiation therapy (IMRT) technique. Preliminary measurements were performed in static conditions. For each of the field angles considered, the motion kernel was generated to simulate tumour motion trajectories, with the largest amplitude in the cranio-caudal direction of 4, 6, and 8 mm. The measurement results determined the agreement between the planned and measured doses. Results: No statistically significant differences were found between the motion patterns, with the smallest amplitudes for clinical target volume in 3DCRT. For IMRT, the significant differences between 0 mm vs. 6 mm and 0 mm vs. 8 mm amplitudes were found. The motion impact on delivered vs. planned doses had less effect on the oesophagus in 3DCRT compared to that in IMRT. The observed differences were comparable for the heart. Interpretation and conclusions: For maximal amplitudes below 4 mm, the disagreement between planned and delivered doses can be neglected. However, the amplitudes above 5 mm and 7 mm lead to significant changes in IMRT and 3DCRT dose distribution, respectively.

Open access

Wojciech Starosta, Viera K. Semina, Jerzy Smolik, Lech Waliś, Michał Rydzewski and Bożena Sartowska

Abstract

Zirconium alloys used widely in nuclear industry as fuel claddings are prone to violent oxidation in water steam atmosphere in the case of loss of coolant accident (LOCA). Accompanying generation of large quantities of heat and explosive gaseous hydrogen may lead to destruction of nuclear core. As the safety of nuclear installations is of primary importance, intensive research works are conducted on the development of so-called accident tolerant fuels much less prone to oxidation. In this paper, the application of external zirconium-silicide coatings deposited by magnetron sputtering is proposed. The preliminary results of their synthesis and studies of air oxidation properties at elevated temperatures are presented.

Open access

Mikołaj Oettingen and Przemysław Stanisz

Abstract

This paper describes the methodology developed for the numerical reconstruction and modelling of the thorium-lead (Th-Pb) assembly available at the Department of Nuclear Energy, Faculty of Energy and Fuels, AGH University, Krakow, Poland. This numerical study is the first step towards integral irradiation experiments in the Th-Pb environment. The continuous-energy Monte Carlo burnup (MCB) code available on supercomputer Prometheus of ACK Cyfronet AGH was applied for numerical modelling. The assembly consists of a hexagonal array of ThO2 fuel rods and metallic Pb rods. The design allows for different arrangements of the rods for various types of irradiations and experimental measurements. The intensity of the fresh neutron source intended for integral experiments is about 108 n/s, which corresponds to the mass of about 43 μg 252Cf. The source was modelled in the form of Cf2O3-Pd cermet wire embedded in two stainless steel capsules.

Open access

Haluk Yücel, R. Bora Narttürk, Senem Zümrüt, Gizem Gedik and Mustafa Karadag

Abstract

The aim of this study was to investigate the thermal neutron measurement capability of a CdZnTe detector irradiated in a mixed gamma-neutron radiation field. A CdZnTe detector was irradiated in one of the irradiation tubes of a 241Am-Be source unit to determine the sensitivity factors of the detector in terms of peak count rate (counts per second [cps]) per neutron flux (in square centimeters per second) [cps/neutron·cm−2·s−1]. The CdZnTe detector was covered in a 1-mm-thick cadmium (Cd) cylindrical box to completely absorb incoming thermal neutrons via 113Cd(n,γ) capture reactions. To achieve, this Cd-covered CdZnTe detector was placed in a well-thermalized neutron field (f-ratio = 50.9 ± 1.3) in the irradiation tube of the 241Am-Be neutron source. The gamma-ray spectra were acquired, and the most intense gamma-ray peak at 558 keV (0.74 γ/n) was evaluated to estimate the thermal neutron flux. The epithermal component was also estimated from the bare CdZnTe detector irradiation because the epithermal neutron cutoff energy is about 0.55 eV at the 1-mm-thick Cd filter. A high-density polyethylene moderating cylinder box can also be fitted into the Cd filter box to enhance thermal sensitivity because of moderation of the epithermal neutron component. Neutron detection sensitivity was determined from the measured count rates from the 558 keV photopeak, using the measured neutron fluxes at different irradiation positions. The results indicate that the CdZnTe detector can serve as a neutron detector in mixed gamma-neutron radiation fields, such as reactors, neutron generators, linear accelerators, and isotopic neutron sources. New thermal neutron filters, such as Gd and Tb foils, can be tested instead of the Cd filter due to its serious gamma-shielding effect.

Open access

Allan Felipe Nunes Perna, Sergei Anatolyevich Paschuk, Janine Nicolosi Corrêa, Danielle Cristine Narloch, Rafael Carvalho Barreto, Flávia Del Claro and Valeriy Denyak

Abstract

The main sources of radon in the air of dwellings are soil, building materials, and groundwater. This study aimed to determine the exhalation rate of 222Rn from samples made of concrete and cement mortars, as well as to evaluate by means of gamma spectrometry the hazard indexes associated with other radionuclides present in the studied samples of building materials. The results obtained allowed the comparison of the exhalation rate of radon using theoretical calculations based on one-dimensional and three-dimensional models. Measurements of the activity concentration of radon in air was performed by AlphaGuard radon detector. Furthermore, obtained results were compared with the measurements performed inside the concrete test cells. These test cells were built with the aim of simulating a dwelling in small dimensions and to evaluate indoor radon activity associated with concrete. Consequently, the obtained results of radon exhalation rate, in becquerel per meter squared per hour, for the concrete was 2.55 ± 0.03 Bq·h−1·m−2 for the 1D model and 0.461 ±0.008 Bq·h−1·m−2 for the 3D model. The exhalation rate of radon, for the cement mortar was 1.58 ± 0.03 Bq·h−1·m−2 for the 1D model and 0.439 ± 0.011 Bq·h−1·m−2 for the 3D model. The indoor concentration of 222Rn from the test cell was 112 ± 9 Bq/m3. These values were below the limit of 300 Bq/m3 recommended by the International Commission on Radiological Protection (ICRP) and <148 Bq/m3, the limit recommended by the US Environmental Protection Agency (US EPA). Even so, these values should be the subject of concern since that activity is related only to the contribution of concrete walls.

Open access

Wojciech Głuszewski, Andrzej Stasiek, Aneta Raszkowska-Kaczor and Daniel Kaczor

Abstract

The process of cross-linking of polyethylene using gamma radiation (γ) and electron beam (EB) was tested from the point of view of density of foam. Particular attention was paid to the postradiation oxidation effect of the polymers. The study used two types of radiation sources of varying dose rates: gamma radiation (4 kGy/h) and EB (14 000 kGy/h). Radiolysis studies of the polymers used the radiation yield of hydrogen evolved (G H2, approximately proportional to the number of radicals) and radiation yield of oxygen absorbed by the polymer (G O2). Oxidation of polymer due to radiation was also evaluated using diffuse reflectance spectroscopy.