IAEA Research Articles

DETERMINATION OF URANIUM CONCENTRATIONS IN RICE SAMPLES AVAILABLE IN THE IRAQI MARKET USING THE CR-39 DETECTOR

In this study, the results of the uranium concentrations and specific activity in 10 rice samples are described using a solid-state track detector (CR-39). Samples were collected from various local Iraqi markets with different origins (Iraq, India, America, and Thailand). Our findings found that the results of uranium concentration in all studied samples are ranging from (0.55 ± 0.28 to 1.74 ± 0.31) ppm with a weighted average of (1.24 ± 0.99) ppm. Also, results demonstrate that the specific activity values of the studied samples swing between values of (6.88 ± 3.52 and 21.49 ± 3.85) Bq/Kg. The obtained results of the studied rice samples are indicated that it is less than the acceptable limit of those studies established by many organizations such as the United Nations scientific committee on the effects of atomic radiation (UNSCEAR), the international atomic energy agency (IAEA), the world health organization (WHO), and others.

Radiation Dose Measurement during CT Abdomen Examination of Adult Patients: A Cross-Sectional Study

Background: Computed tomography (CT) has become a routine imaging modality for many clinical applications due to its wide availability, minimally invasiveness, short scan time, excellent anatomical resolution, and high diagnostic value. The radiation dose to patients from CT examinations is the highest contributor to diagnostic medical exposure, which is a growing public concern. The aim of this study was to measure radiation doses for abdominal CT examinations in adult patients and compared them to international standard dose values. Methods: A cross-sectional study was conducted on 92 adult patients with abdomen CT scans using a 16-slice computed tomography scanner at the department of Radiodiagnosis & Medical Imaging, UCMS-TH, Bhairahawa, Nepal from August 2018 to January 2019. The radiation doses were measured by convenient techniques: volumetric computed tomography dose index (CTDIvol), dose length product (DLP) & effective dose (ED) and data were analyzed using SPSS version 20. Results: The mean BMI of the study participants was 23.92±4.29 kg/m2. The mean values of contrast-enhanced scan CTDIvol, DLP, and an ED in our study were 7.31 mGy, 421.46 mGy.cm and 6.31 mSv respectively which is very low as compared to European Guidelines (EG) & International Atomic Energy Agency (IAEA). There was a statistically significant association between patient BMI with CTDIvol, DLP and ED during non-contrast, contrast-enhanced and delayed scans. Conclusion: The CTDIvol, DLP, and ED were lower than the European guidelines and IAEA standards. Toward preventing health effects from ionizing radiation, our study follows public concerns and minimizes radiation doses.

DEVELOPING AND IMPLEMENTING THE QUALITY CONTROL PROGRAM ON A LINEAR ACCELERATOR

Relevance: The article deals with modern problems in the field of ensuring the quality of services provided on linear accelerators from the point of view of the regulatory framework, as well as from the point of view of the frequency of control procedures. The scientific novelty lies in elaborating a linear accelerator quality control program with detailed procedure descriptions and testing frequency recommendations.
 The study aimed to – develop and test a set of simple methods for controlling the linear accelerator’s mechanical and dosimetric parameters, which would meet the minimum requirements for high-tech radiation therapy following IAEA and AAPM international recommendations.
 Methods: In developing the quality control program for the TrueBeamSTx linear accelerator (Varian, USA) installed at the Almaty Oncological Center (AOC, Kazakhstan), we relied on the recommendations of the International Atomic Energy Agency (IAEA) and the American Association of Physicists in Medicine (AAPM), taking into account that intensity-modulated radiotherapy (IMRT, VMAT), stereotactic radiosurgery and stereotactic radiotherapy (SRS, SRT), using image-guided radiation therapy (IGRT) will be performed on the accelerator, which imposes more stringent requirements for control of both mechanical and dosimetry characteristics
 Results: Over three years of operation, the TrueBeamSTx accelerator shows good stability of mechanical and dosimetric characteristics, verified using systematic tests according to the quality control program developed by the authors of this article. The IAEA/WHO mail dose monitoring program using radiophotoluminescent detectors, implemented in 2019-2022, showed high dosimetric measurements and calculations accuracy of 0.1-1.7%, at a tolerance of 5%.
 Conclusion: A quality control program for a high-energy linear accelerator has been developed; the results obtained for all characteristics correspond to the permissible values. The effective and safe use of radiotherapy requires the development of a quality control program for all radiotherapy equipment specifically for each institution and independent verification of the implementation of this program.

PETRA: A pencil beam trimming algorithm for analytical proton therapy dose calculations with the dynamic collimation system.

The Dynamic Collimation System (DCS) has been shown to produce superior treatment plans to uncollimated pencil beam scanning (PBS) proton therapy using an in-house treatment planning system (TPS) designed for research. Clinical implementation of the DCS requires the development and benchmarking of a rigorous dose calculation algorithm that accounts for pencil beam trimming, performs monitor unit calculations to produce deliverable plans at all beam energies, and is ideally implemented with a commercially available TPS. To present an analytical Pencil bEam TRimming Algorithm (PETRA) for the DCS, with and without its range shifter, implemented in the Astroid TPS (.decimal, Sanford, Florida, USA). PETRA was derived by generalizing an existing pencil beam dose calculation model to account for the DCS-specific effects of lateral penumbra blurring due to the nickel trimmers in two different planes, integral depth dose variation due to the trimming process, and the presence and absence of the range shifter. Tuning parameters were introduced to enable agreement between PETRA and a measurement-validated Dynamic Collimation Monte Carlo (DCMC) model of the Miami Cancer Institute's IBA Proteus Plus system equipped with the DCS. Trimmer position, spot position, beam energy, and the presence or absence of a range shifter were all used as variables for the characterization of the model. The model was calibrated for pencil beam monitor unit calculations using procedures specified by International Atomic Energy Agency Technical Report Series 398 (IAEA TRS-398). The integral depth dose curves (IDDs) for energies between 70 MeV and 160 MeV among all simulated trimmer combinations, with and without the ranger shifter, agreed between PETRA and DCMC at the 1%/1mm 1-D gamma criteria for 99.99% of points. For lateral dose profiles, the median 2-D gamma pass rate for all profiles at 1.5%/1.5mm was 99.99% at the water phantom surface, plateau, and Bragg peak depths without the range shifter and at the surface and Bragg peak depths with the range shifter. The minimum 1.5%/1.5mm gamma pass rates for the 2-D profiles at the water phantom surface without and with the range shifter were 98.02% and 97.91%, respectively, and, at the Bragg peak, the minimum pass rates were 97.80% and 97.5%, respectively. The PETRA model for DCS dose calculations was successfully defined and benchmarked for use in a commercially available TPS.

Perils, promises and perspectives: nuclear weapons, atomic energy and the International Confederation of Free Trade Unions in the early Cold War

ABSTRACT In the 1950s and 1960s, the International Confederation of Free Trade Unions (ICFTU) protested nuclear weapons testing, called for nuclear and conventional disarmament, and simultaneously embraced the promises of atomic energy. The ICFTU also, particularly through its atomic energy committee, pressed the United Nations (UN), the International Labour Organization (ILO) and the new International Atomic Energy Agency (IAEA) for stronger worker protections and union input at atomic energy sites. Such efforts revealed how a non-governmental organization (NGO) attempted to shape international narratives and standards regarding nuclear weapons and atomic energy, revealing a complex approach to the use of the atom.

Application of risk-based approach in switching operations preparation at Novovoronezh NPP

The article discusses one of the problematic issues of operating nuclear power plants - revenue losses caused by staff mistakes. Existing methods and approaches to reducing the number of such incidents are analyzed. Despite the efforts made, the problem remains relevant. One of the directions for reducing the number of equipment failures is the study and use of internal and external operational experience. A description is given of a system for preventing the recurrence of negative operating experience, developed at the Novovoronezh Nuclear Power Plant, which is used in preparation for switching equipment. The system is an information base, the information in which is structured by types of equipment used at the Novovoronezh Nuclear Power Plant, allowing only the information directly related to the upcoming switches to be communicated to the operational staff. Suggestions for its further improvement, taking into account the recommendations of the International Atomic Energy Agency, are considered. A forecast is given for the dynamics of reducing the number of violations after the introduction of this system into industrial operation.​

A Source-Related Approach for Discussion on Using Radionuclide-Contaminated Materials in Post-accident Rehabilitation

Background: In the process of discussion on the possibility of using radionuclide-contaminated soil and debris generated by radiation disasters, a strategy for the proper management of radiation exposure protection while considering the source of the contaminated materials is necessary.Materials and Methods: The radiological protection criteria that are likely to be applied to the source-related approach based on the International Commission on Radiological Protection recommendations and the International Atomic Energy Agency safety standards are summarized. We proposed five interpretations of radiation protection to contribute to the promotion of discussion on the possibility of using a part of low-level-radionuclide-contaminated soil and debris in the post-accident rehabilitation. Interpretations I to III are based on the idea of “using a reference level to protect the public in post-accident rehabilitation,” whereas IV and V are based on the idea of “using the dose constraint to protect the public in the post-accident rehabilitation when the sources are handled in a planned activity.” The former idea is subdivided into three based on the definition of the source, which is managed by the reference level, and the latter idea is divided into two depending on whether or not additional dose from using contaminated materials is deemed acceptable.Results and Discussion: To confirm the applicability of the five interpretations presented, we suggested the concrete values of protection criteria via two feasible cases. In this case study, we proposed radiation protection by the dose constraint based on the Interpretation IV and chose 1 mSv/yr for the public and 20 mSv/yr for workers dealing with radionuclide-contaminated materials.Conclusion: We concretely and systematically demonstrated how the concept of radiation protection can be applied to the process of discussion on the possibility of using radionuclide-contaminated materials within the framework of an international system of protection. This study’s findings can provide necessary information to discuss the possibility of using radionuclide-contaminated materials as an alternative option for recovery and reconstruction after a radiation disaster from the viewpoint of radiation protection.

SAFE MANAGEMENT OF MEDICAL RADIOLOGICAL WASTE

The International Atomic Energy Agency (IAEA) defines radioactive waste as material, of no useful value, that contains or is contaminated with nuclides in concentrations higher than levels specified by relevant bodies. Healthcare institutions and users whose business activities generate radioactive waste have the obligation to collect, label and store it in the prescribed manner until such time as it is taken over by a company which is authorized for its transportation, collection, keeping and storage. The goal of this paper is to point out the importance of improving the quality of health services through the process of regulating medical waste management, with a focus on measures and procedures for the disposal of waste generated in radiology. The system for the separation of radiological waste, and its adequate labeling with a number corresponding to its category, is a top priority for radiological waste management at all health institutions. The importance of controlling the generation of radioactive waste is primarily reflected in measures that contribute to its reduction, followed by reuse and recycling. Data on physical, mechanical, chemical, radiological, and biological characteristics is provided to characterize radioactive waste, thus ensuring its safe and secure management. The storage of radioactive waste is the procedure for the temporary placement of radioactive waste in a dedicated facility, i.e., in a warehouse for a specific period of time, in compliance with the prescribed measures for radiation and nuclear safety and the safety of stored waste. During the storage of radioactive waste, it is necessary to carry out a whole series of activities: radiation protection, monitoring radioactivity in the environment around the warehouse, inspection of the state of radioactive waste packaging and inspection of equipment, warehouse components and systems, maintenance of the warehouse, and the labeling and recording of radioactive waste packaging. The process for disposing of radioactive waste implies its isolation from people and the environment. While the location, designed barriers and operation of the facility for disposal of radioactive waste, should enable the application of all radiation safety and security measures and the prevention of reaching criticality. States should assume an unequivocal ethical obligation to eliminate the unnecessary burden, associated with the complex issue of radioactive waste disposal, from future generations.

Gyrokinetic simulation of electromagnetic instabilities in the high β p scenario on EAST

High poloidal beta scenarios with favorable plasma performance () have be achieved on Experimental Advanced Superconducting Tokamak (EAST) since the 2018 international atomic energy agency (IAEA). Linear electromagnetic gyrokinetic simulations using gyrokinetic toroidal code (GTC) code are performed based on the experimental data of a typical high discharge on EAST. In the core region of plasma, an electromagnetic instability with similar dependence and mode structure with kinetic ballooning mode (KBM) but exhibits positive or nearly zero frequency is observed. This instability is referred as unconventional KBM (UKBM). Simulation results demonstrate that UKBM occurs in low ion–electron temperature ratio conditions and UKBM will transit to KBM when ion–electron temperature is high. Further investigation shows the driven mechanism of UKBM differs at different electron beta region. When the electron beta exceeds the threshold of electrostatic instability to UKBM, UKBM is driven by electron pressure gradient. When electron beta is close to the beta threshold of UKBM, the main driven mechanism is . Reversed magnetic shear is found to have a significant stabilize effect on UKBM.

Evaluation of the function of polymeric bentonite adsorbent to retain strontium and cobalt radionuclides in OPC matrices

The effect of polyacrylamide-bentonite (PAAmB) as an adsorbent/cement-enhancement material was examined for the retention of strontium (Sr2+) and cobalt (Co2+) ions from aqueous system. PAAmB composite was synthesized and analyzed by diverse characterization techniques. The acquired experimental data revealed that the addition of bentonite to polyacrylamide polymer (PAAmP) enhanced the adsorption of strontium and cobalt ions capacities. To examine the adsorption mechanism onto PAAmB, the experimental data were fitted using hyperbolic and Langmuir equations at different temperatures. It was found that the adsorption nature was chemisorption and the adsorbed amount of the studied ions increased with increasing the temperature. Immobilization of spent polyacrylamide-bentonite composite loaded with 85Sr and 60Co radionuclides in different extents with Ordinary Portland Cement (OPC) was investigated. The results showed that the optimal compressive strength was attained at OPC blended with 5% PAAmB composite. The leaching patterns of the studied radionuclides from the immobilized waste form were compared with the standard static long-term leaching approach of International Atomic Energy Agency (IAEA). The cumulative leaching fraction (CLF) of the studied radionuclides from PAAmB-OPC was found to be < 5% in all scrutinized conditions, which suggests the applicability of the IAEA-recommended approach for assessing the diffusion coefficient. The acquired leaching data were nonlinearly regressed with numerous mathematical kinetic models to determine the leaching parameters and to evaluate the prevailing leaching mechanism. The results from the regression scrutiny showed that 85Sr and 60Co leaching resulted from three succeeding leaching mechanisms that were the first-order reaction exchange among the waste matrix surface and the leaching solution, diffusion and dissolution. Compliant with IAEA, the calculated leachability indices values implied that the studied matrices performance was within a suitable range and the immobilized spent PAAmB matrices had an adequate mechanical efficacy.

The rule of law: A fragile tool for the development of emerging nuclear technologies

Before the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011, the nuclear industry had strongly promoted the idea that the time of nuclear renaissance had come after a long, fallow period in the wake of the nuclear accidents at Three Mile Island (1979) and Chernobyl (1986). During the post-Fukushima period, there were few new projects, but growing demand for energy and anxieties raised by climate change have brought us to a turning point. Despite the Fukushima accident, which led to some nuclear projects being delayed or cancelled, there is still a great deal of interest in the use of nuclear power for civil purposes. This is primarily because, as the International Energy Agency’s (IEA) Executive Director Fatih Birol has rightly pointed out: “Without an important contribution from nuclear power, the global energy transition will be that much harder.”1 In this regard, in 2010, 67 reactors were under construction, 120 planned and 441 in operation.2 In 2022, 11 years after the Fukushima Daiichi accident, there were 60 under construction, 104 planned and 338 proposed.3 The International Atomic Energy Agency (IAEA) estimates that nuclear electric power capacity will have increased by as much as 23% by 2030 and more than doubled by 2050.4 In addition to this renewed interest, many projects are now in development, opening up new prospects for the use of the atom for civil purposes. Nuclear fusion, small modular reactors (SMRs), the use of artificial intelligence, floating, underwater and space reactors, and nuclear batteries, to name but a few of the projects on the table, lead us to think that the “nuclear renaissance” is slowly shifting to a “nuclear spring”. In this view, where the concept of a renaissance involves new impetus for nuclear energy, with the construction of new facilities, the concept of “spring” refers to a determination to break with nuclear traditions, in terms of concepts, means and players. Consequently, this phenomenon calls for new legal rules which, in some cases, have already started to be debated.

Pulmonary disorders in pregnancy – Volume 85 multiple choice questions - Answers

The ARRONAX cyclotron, acronym for “Accelerator for Research in Radiochemistry and Oncology at Nantes Atlantique” is a new facility installed in Nantes, France. A dedicated program has been launched on production of innovative radioisotopes for PET imaging and for β − and α targeted radiotherapy using protons or α particles. Since the accelerator is also able to deliver deuteron beams up to 35 MeV, we have reconsidered the possibility of using them to produce medical isotopes. Indeed, in some cases, the use of deuterons allows higher production yield than protons.186Re is a β − emitter which has chemical properties close to the widely used 99mTc and has been used in clinical trials for palliation of painful bone metastases resulting from prostate and breast cancer. 186Re production cross section has been measured between 9 and 23 MeV using the ARRONAX deuteron beam and the stacked-foil technique.A novelty in our work is the use of a monitor foil behind each natW target foil in order to record efficiently the deuteron incident flux and energies all over the stack relying on the International Atomic Energy Agency (IAEA) recommended cross section of the natTi(d,x)48V reaction. Since a good optimization process is supposed to find the best compromise between production yield and purity of the final product, isotope of interest and contaminants created during irradiation are measured using gamma spectrometry.Our new sets of data are presented and compared with the existing ones and with results given by the TALYS code calculations. The thick target yield (TTY) has been calculated after the fit of our experimental values and compared with the IAEA recommended ones.Presented values are in good agreement with existing data. The deuteron production route is clearly the best choice with a TTY of 7.8 MB/μAh at 30 MeV compared to 2.4 MBq/μAh for proton as projectile at the same energy. The TALYS code gives satisfactory results for 183,186Re isotopes.

Establishment of ex vivo calibration curve for X-ray induced “dicentric + ring” and micronuclei in human peripheral lymphocytes for biodosimetry during radiological emergencies, and validation with dose blinded samples

In the modern developing society, application of radiation has increased extensively. With significant improvement in the radiation protection practices, exposure to human could be minimized substantially, but cannot be avoided completely. Assessment of exposure is essential for regulatory decision and medical management as applicable. Until now, cytogenetic changes have served as surrogate marker of radiation exposure and have been extensively employed for biological dose estimation of various planned and unplanned exposures. Dicentric Chromosomal Aberration (DCA) is radiation specific and is considered as gold standard, micronucleus is not very specific to radiation and is considered as an alternative method for biodosimetry. In this study dose response curves were generated for X-ray induced “dicentric + ring” and micronuclei, in lymphocytes of three healthy volunteers [2 females (age 22, 23 years) and 1 male (24 year)]. The blood samples were irradiated with X-ray using LINAC (energy 6 MV, dose rate 6 Gy/min), in the dose range of 0–5Gy. Irradiated blood samples were cultured and processed to harvest metaphases, as per standard procedures recommended by International Atomic Energy Agency. Pooled data obtained from all the three volunteers, were in agreement with Poisson distribution for “dicentric + ring”, however over dispersion was observed for micronuclei. Data (“dicentric + ring” and micronuclei) were fitted by linear quadratic model of the expression YC + αD + βD2 using Dose Estimate software, version 5.2. The data fit has resulted in linear coefficient α = 0.0006 (±0.0068) “dicentric + ring” cell−1 Gy−1 and quadratic coefficient β = 0.0619 (±0.0043) “dicentric + ring” cell−1 Gy−2 for “dicentric + ring” and linear coefficient α = 0.0459 ± (0.0038) micronuclei cell−1 Gy−1 and quadratic coefficient β = 0.0185 ± (0.0010) micronuclei cell−1 Gy−2 for micronuclei, respectively. Background frequencies for “dicentric + ring” and micronuclei were 0.0006 ± 0.0004 and 0.0077 ± 0.0012 cell−1, respectively. Established curves were validated, by reconstructing the doses of 8 dose blinded samples (4 by DCA and 4 by CBMN) using coefficients generated here. Estimated doses were within the variation of 0.9–16% for “dicentric + ring” and 21.7–31.2% for micronuclei respectively. These established curves have potential to be employed for biodosimetry of occupational, clinical and accidental exposures, for initial triage and medical management.

Radioactive Fission Waste of The Conversion of High-Enriched Uranium to Low-Enriched Uranium Target on 99Mo Production

In the past, 99mTc produced by PT. Industri Nuklir Indonesia (PT. INUKI) was carried out through the processing of a 99Mo parent radioisotope that was produced using high enriched uranium target. Due to restrictions on the use of high-enriched uranium (HEU) by the International Atomic Energy Agency, PT. INUKI has converted the process using a low enriched uranium (LEU) target. This study aims to determine the change of radioactive fission waste characteristics in 99Mo production due to the conversion process. The characteristics of radioactive fission waste generated from low-enriched uranium targets were calculated using ORIGEN 2.1 program. The results show that the radioactive fission waste contains radionuclides of activation products, actinides, and fission products. The conversion produced smaller activity of 99Mo compared to that of using the HEU target, which was 397 compared to 1010 Ci. The conversion generated radioactive fission waste with a smaller content of remaining 235U but greater content of actinides, particularly 239Pu. The activity of 239Pu in the radioactive fission waste from LEU was 29.1 μCi, approximately 19 times higher compared to that of using HEU, which was 1.52 μCi. After 50 years of decay, this radioactive fission waste was calculated to have a specific activity of 6.54x108 Bq/g, lower than that of the highly enriched uranium target, which was 3.01x109 Bq/g. This radioactive fission waste requires management with a high safety level.

Abstract 74: Supporting African Countries in Developing Cancer Control Programmes: The Added Value of South-South Cooperation

Abstract Purpose: Advisory support to develop National Cancer Control Programmes (NCCP) is one of the services offered to Ministries of Health by the International Atomic Energy Agency’s (IAEA) Programme of Action for Cancer Therapy (PACT), the World Health Organization (WHO) and the International Agency for Research on Cancer (IARC) within the framework of the WHO-IAEA Joint Programme on Cancer Control. The aim is to assist Member States in developing evidence-based, prioritized, country-specific strategic documents and to strengthen regional coordination to tackle the raising burden of cancer. Methods: IAEA-WHO-IARC support to develop NCCPs is provided through international experts covering the entire continuum of cancer control. The work encompasses the identification of the country’s needs and capacities through a detailed situational analysis, regular meetings with the team appointed by the Ministry of Health, and in-country workshops with national stakeholders, including civil society organizations, academia, and cancer survivors. Regional experts are involved to give a strategic direction to improve cancer prevention and control services taking into consideration common best practices and challenges. Results: In the African region the involvement of regional experts strengthened south-south cooperation through the creation of a network of cancer control professionals that can share experiences and lessons learned, paving the way for possible partnerships to implement cancer control priorities. In countries such as Botswana, Zambia and Zimbabwe this approach facilitated the establishment of a dialogue that fostered longer-lasting mutual support for capacity building and the exchange of knowledge to advance the implementation of cancer control activities in sustainable ways. Conclusion: The development of an NCCP is a critical first step to ensure that effective national responses are put in place to reduce the challenges posed by cancer. This leads to the implementation of priority activities through strategic partnerships, strong coordination mechanisms and resource mobilization to achieve the objective of reducing cancer incidence and mortality. A robust NCCP becomes also the foundation document to further support countries in establishing and expanding radiation medicine services through different initiatives, such as the recently launched Rays of Hope, directly contributing to fulfil the 2030 Agenda and Sustainable Development Goals. Citation Format: Marianna Nobile, Tlotlo Ralefala, Kennedy Lishimpi, Justice Mudavanhu. Supporting African Countries in Developing Cancer Control Programmes: The Added Value of South-South Cooperation [abstract]. In: Proceedings of the 11th Annual Symposium on Global Cancer Research; Closing the Research-to-Implementation Gap; 2023 Apr 4-6. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(6_Suppl):Abstract nr 74.

Characterization of NORM‐type scales from the oil industry through spectrometry techniques and multivariate analysis

AbstractThe oil industries have as main problem in their activities of formation of scales containing material of the naturally occurring radioactive material (NORM) type on the internal walls of pipes and in some equipment that make up the process lines plant. This NORM can contribute to the exposure of workers during routine activities, either through external exposure, or internal, through inhalation or ingestion. Considering the concern with occupational exposure, environmental impacts and the plant's production capacity, resulting from the formation of the scales, this work characterized samples of scale by means of techniques of x‐ray fluorescence (XRF), x‐ray diffraction (XRD) and high‐resolution gamma spectrometry. The XRF showed concentrations of P, S, Cl, Ca, Mn, Fe, Sr, and Ba as the main elements of the sample; the XRD showed calcite and barite as predominant composition; in the gamma analysis, the concentrations of the activities varied from 104.6 to 1112.6 Bq kg−1 for 226Ra and from 16.4 to 385.2 Bq kg−1 for 228Ra, within the limits set by the International Atomic Energy Agency. The indices radium equivalent activity, absorbed dose rate and annual effective dose indices varied from 128.4 to 1665.9 Bq kg1; 58.4 to 748.0 nGy h−1 and 0.072 to 0.918 mSv y−1, respectively. Only the effective dose values ​​were within the limits established by United Nations Scientific Committee on the Effects of Atomic Radiation, reinforcing the need for continuous monitoring on the platforms and the importance of keeping the radiological protection plan up to date, since the mobilization of NORM increases proportionally with the useful life of the production wells, thus increasing exposure indices.

In-field alpha spectrometry system for uranium enrichment verification of uranium hexafluoride

A portable In-Field Alpha Spectrometry (IFAS) system was developed to support on-site uranium enrichment determination for samples taken at facilities working with gaseous UF6. It consists of a modified commercial alpha spectrometer, a vacuum pump, a laptop computer, and associated connectors and cables. The IFAS uses specially designed Single-Use Destructive Assay (SUDA) samplers to capture gaseous UF6 and convert and store it as UO2F2 in a thin-film zeolite. To examine the quantitative performance of the IFAS system a large number of replicate SUDA samples was acquired for natural uranium (NU, 0.72 wt%, 23 samples), low enriched uranium 1 (LEU1, 2.33 wt% 235U, 10 samples), and low enriched uranium 2 (LEU2, 4.62 wt% 235U, 10 samples). The standard deviation (SD) values for uranium enrichment determination with the IFAS for NU, LEU1, and LEU2, in 20-hour assays, were 0.037 wt% 235U, 0.063 wt% 235U, and 0.072 wt% 235U, respectively. A separate analysis suggests that comparable SD values can be achieved in less time, approximately 8–10 h. For context, these SD values are well below the International Atomic Energy Agency’s International Target Values for the determination of uranium enrichment in non-destructive assay measurements.

Regulation and Supervision of Food Irradiation

Food irradiation consists of a physical process that subjects food to doses of ionizing radiation, which are high enough energy to eliminate or neutralize harmful microbial contaminants without changing the taste or texture of food and without leaving residues. With this irradiation process we can prevent diseases transmitted by food, such as Salmonella and Escherichia coli, prolong the shelf life of foods, control pests that harm fruits by delaying germination and ripening, and finally sterilization, which allows their storage for years without refrigeration. The use of ionizing radiation for food preservation has been studied for several decades and is regulated in the USA by the Food and Drug Administration –FDA. In 1997, the World Health Organization - WHO released the use of the technique for all types of food. In Brazil, the first studies on food irradiation were carried out by the Center for Nuclear Energy in Agriculture - Cena, in the 50's. Currently, Brazilian legislation follows the international recommendations suggested by the Food and Agriculture Organization - FAO, the International Atomic Energy Agency - IAEA and Codex Alimentarius. The scope of this work is a survey, analysis and evolution of national and international legislation related to ionizing irradiation practices in food. For the preparation of this research, bibliographical reviews were carried out, consultations in Brazilian and international legislation, Internet sites, and in the documentation of the Gamma Irradiation Laboratory of the Nuclear Technology Development Center - CDTN

A reconsideration of photoneutron production through a 5 MeV electron LINAC using MCNP and FLUKA

In the present study, photoneutron production using a 5 MeV electron linear accelerator (LINAC) was investigated based on new photoneutron cross-sections (IAEA/PD-2019.2) from the International Atomic Energy Agency (IAEA). A detailed reconsideration of a past study has been done in order to make a photoneutron source based on a heavy water target. In this regard, new cross-sections of deuterium and beryllium were added to the library of the MCNP6.1 Monte Carlo code for the simulation of photoneutron production. In addition, the FLUKA4-3.0 Monte Carlo code was employed for comparison and data validation. Moreover, the obtained results from those two codes (MCNP and FLUKA) were compared and discussed with the theory and the previous study. Finally, it is concluded that the simulation of photoneutron production through an electron LINAC can have relatively different results based on the photoneutron cross-sections and even on the Monte Carlo code used. Therefore, a special attention should be paid to the difference between photoneutron cross-sections as well as the difference in Monte Carlo codes to maintain reliability.

Global Radioactive Waste Disposal Trends and Prospects

Nuclear power generation, which began in the Soviet Union in June 1954, has now become a main source of electrical energy in 33 countries around the world. However, radioactive waste and its safety have always been at the center of controversy, and even after 70 years, there is no official regulation on the disposal of radioactive waste under international law. In this review, the policies and current status of radioactive waste disposal in major countries around the world, including Korea, are investigated. Based on this, the direction for radioactive waste management in Korea was presented. Currently, radioactive waste is disposed of in two ways. Finland, Sweden, and France are conducting deep permanent disposal according to the recommendation of the International Atomic Energy Agency, and Japan, the United Kingdom, and India are promoting reprocessing of spent nuclear fuel to reduce waste and the volume of the repository. Korea has been temporarily storing radioactive waste at the site of the power plant since the completion of Kori Unit 1 in 1978, but it is expected that the capacity of the temporary storage facility will reach its limit in 2031. Accordingly, the securing of a permanent disposal site and the development of reprocessing technology are being studied together, but no tangible results have been achieved so far. Korea's radioactive waste disposal has problems such as a small land area, institutional difficulties in developing reprocessing technology, frequent policy changes, ignorance and indifference, and lack of smooth communication. Although public concern about nuclear power generation has increased due to the Fukushima disaster, not many people are interested in spent nuclear fuel. Within the framework of reprocessing and permanent disposal, Korea should refrain from frequent policy changes that can confuse public opinion and research and development, and come up with a long-term realistic policy.