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1.
Sci Rep ; 12(1): 8276, 2022 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-35585120

RESUMO

We open an avenue for discussing how we can pave the way for compliance with existing regulations is a far-reaching factor for settling nuclear fusion technology. Based on a model of the Korean Fusion Demonstration Reactor (K-DEMO) with a target fusion power of 2.2 GW, we assess the intrinsic safety determinants of internal energy sources, the expected radioactive waste, and the tritium management. Regarding these safety factors, we scrutinize the compatibility of the current legislative environment in Korea with K-DEMO and envisage foreseeable obstacles, such as licensing of the nuclear facilities and acceptability of the radioactive waste. Based on precedent licenses for the Korean Superconducting Tokamak Advanced Research (KSTAR) and lessons learned from the International Thermonuclear Experimental Reactor (ITER), we examine hazardous factors that would threaten regulatory compliance of K-DEMO. This approach can help shape a fusion-compatible framework for consolidating the necessary technical provisions and regulatory baselines reflecting social acceptance with a sense of safety. Fusion-compatible aspects in the regulatory environment are discussed, from fusion philosophy to subordinate administrative and technical guidelines, facility classification, and detailed methods guaranteeing integrity and safety. This paper will contribute to the timely settlement of fusion demonstration facilities and subsequent commercial plants.


Assuntos
Resíduos Radioativos , Fontes Geradoras de Energia , Fusão Nuclear , Reatores Nucleares , Trítio
2.
Appl Radiat Isot ; 185: 110259, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35504147

RESUMO

In the Republic of Kazakhstan, within the framework of international initiatives on the non-proliferation of nuclear weapons, the IVG.1M research reactor is being converted to low enriched fuel. Due to the change in the fuel composition, it becomes necessary to assess the power density distribution in the fuel assemblies and in the core altogether. Close attention to this parameter is explained by the fact that the non-uniformity of the radial and axial power density fields determines the operating parameters of the reactor, its power, the core resource and the efficiency of fuel utilization. The purpose of this work is approbation of the activation gamma-spectrometry method for determining the power density distribution in the fuel of the IVG.1M research reactor after conversion. Additionally, for a preliminary assessment of the experimental outcomes, the paper presents the MCNP6 calculation results for the power distribution in fuel assemblies and the peaking factors.


Assuntos
Reatores Nucleares , Espectrometria gama
3.
Eur J Epidemiol ; 37(3): 221-225, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35426580

RESUMO

Recent incidents at nuclear facilities in Ukraine related to the attacks from Russian forces highlight the fragility of nuclear power plants and other nuclear facilities in war and the very real potential for another environmental nuclear disaster and associated health risks in Europe. Nuclear catastrophes from war can occur from radioactive materials released from war threatened nuclear power plants and other nuclear facilities in war zones, in addition to the direct threat from the deployment of nuclear weaponry and can result in immediate and long-term health impacts. Despite historical nuclear catastrophic events, including the Chernobyl nuclear power plant accident and atomic bombings of Hiroshima and Nagasaki, and that for more than a century epidemiologists have studied the consequences of radiation exposures, there are still major unanswered questions regarding radiation risks and human health. Epidemiologists will need to continue to quantify the health effects from exposure to environmental radiation, including background radiation, and are able to contribute to conversations about reliance on nuclear energy and alternative energy futures. As a society we are compelled to rethink our ties to nuclear energy, especially with the potential of increasing reliance on nuclear power amid oil and gas crisis and considering climate change, nuclear warfare, including nuclear weapon testing, and the fragility of humanity and health to even low doses of radiation from these and other natural and unnatural sources.


Assuntos
Acidente Nuclear de Chernobyl , Desastres , Armas Nucleares , Europa (Continente) , Humanos , Reatores Nucleares
5.
Technol Cult ; 63(1): 1-30, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35000957

RESUMO

This article argues that the history of nuclear energy can and should be analyzed as a history of water. Taking inspiration from David Edgerton's The Shock of the Old and recent efforts to merge the history of technology with environmental history, here the focus shifts from nuclear reactors to the "conventional" parts of nuclear power plants. This brings to the fore that a range of hydraulic technologies with long prehistories-pumps, pipes, valves, dams, dikes, and so on-have been crucially important for nuclear safety. The "atomic age" is fundamentally a hydraulic age and should be seen in relation to experiences gathered by past hydraulic civilizations.


Assuntos
Energia Nuclear , Água , Centrais Nucleares , Reatores Nucleares
6.
J Radiol Prot ; 42(2)2022 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-35023506

RESUMO

This paper reports on the findings from the study of mortality from diseases of the circulatory system (DCS) in Russian nuclear workers of the Mayak Production Association (22 377 individuals, 25.4% female) who were hired at the facility between 1948 and 1982 and followed up until the end of 2018. Using the AMFIT module of the EPICURE software, relative risks (RRs) and excess RRs per unit absorbed dose (ERR/Gy) for the entire Mayak cohort, the subcohort of workers who were residents of the dormitory town of Ozyorsk and the subcohort of migrants from Ozyorsk were calculated based on maximum likelihood. The mean cumulative liver absorbed gamma-ray dose from external exposure was 0.45 (0.65) Gy (mean (standard deviation)) for men and 0.37 (0.56) Gy for women. The mean cumulative liver absorbed alpha dose from internal exposure to incorporated plutonium was 0.18 (0.65) Gy for men and 0.40 (1.92) Gy for women. By the end of the follow-up, 6019 deaths with DCS as the main cause of death were registered among Mayak Production Association workers (including 3828 deaths in the subcohort of residents and 2191 deaths in the subcohort of migrants) over 890 132 (622 199/267 933) person-years of follow-up. The linear model that took into account non-radiation factors (sex, attained age, calendar period, smoking status and alcohol drinking status) and alpha radiation dose (via adjusting) did not demonstrate significant associations of mortality from DCS, ischaemic heart disease (IHD) and cerebrovascular disease with gamma-ray exposure dose in the entire cohort, the resident subcohort or the migrant subcohort (either in men or women). For the subcohort of residents, a significant association with gamma dose was observed for mortality from ischaemic stroke in men with ERR/Gy = 0.43 (95% CI 0.08; 0.99); there were no significant associations with liver absorbed gamma dose for any other considered outcomes. As for internal exposure, for men no significant associations of mortality from any DCS with liver absorbed alpha dose were observed, but for women positive associations were found for mortality from DCS (the entire cohort and the resident subcohort) and IHD (the entire cohort). No significant associations of mortality from various types of DCS with neutron dose were observed either in men or women, although neutron absorbed doses were recorded in only 18% of the workers.


Assuntos
Isquemia Encefálica , Sistema Cardiovascular , Doenças Profissionais , Exposição Ocupacional , Acidente Vascular Cerebral , Feminino , Humanos , Masculino , Reatores Nucleares , Exposição Ocupacional/efeitos adversos , Federação Russa/epidemiologia
7.
Appl Radiat Isot ; 179: 110018, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34749092

RESUMO

Glioblastoma multiforme is the most common and aggressive brain tumor and it is difficult to treat with conventional surgery, chemotherapy, or radiation therapy. An alternative treatment is boron neutron capture therapy which requires an energy modulated beam of neutrons and a10B drug capable of adhering to the tumor. In this work, MCNP6 Monte Carlo code was used to evaluate the effect on the neutron spectrum by placing two filters along the radial beam tube of the TRIGA Mark III nuclear reactor of ININ in Mexico. Every filter was made with the same amount and type of materials: Steel and Graphite for filter 1 and Cadmium, Aluminum, and Cadmium (Cd + Al + Cd) for filter 2. Two cases were analyzed for each filter as follows: Case A for filter 1 was considering 30 cm of steel and 30 cm of graphite, while for case B, the dimensions of filter 1 were 15 cm of steel, 15 cm of graphite, 15 cm of steel and 15 cm of graphite. Cases A and B for filter 2 were analyzed considering the same dimensions and amount of materials. The work was in the aim to produce epithermal neutrons for boron neutron capture therapy. Neutron spectra were calculated at three sites along the beam tube and two sites outside the beam tube; here, the ambient dose equivalent, the personal dose equivalent, and the effective doses were also estimated. At a distance of 517 cm of core, in case B, results in an epithermal-to-thermal neutron fluence ratio of 30.39 was obtained being larger than the one recommended by the IAEA of 20.


Assuntos
Terapia por Captura de Nêutron de Boro/métodos , Neoplasias Encefálicas/radioterapia , Glioblastoma/radioterapia , Nêutrons , Humanos , Método de Monte Carlo , Reatores Nucleares
8.
J Emerg Manag ; 19(6): 541-559, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34878164

RESUMO

High-reliability organizations (HROs) including commercial airlines, the NASA Space Shuttle engineering team, US Naval aircraft carrier and nuclear submarine crews, and US nuclear power plants are relatively safe. However, these organizations experience system breakdowns often with catastrophic outcomes. This study focuses on risk information management strategies employed by a nuclear energy power plant located within 10 miles of a population center. The evacuation planning zone (EPZ) includes a hospital, several schools, and a public university. The nuclear plant provides written preparedness and evacuation information for all residents within the EPZ in the event of a radiological emergency. Focusing on the campus community within the EPZ, this study investigates individual awareness regarding the potential of a radiological event, the emergency information booklet, and the information provided within the booklet. We use descriptive statistics, frequency distribution, and cross tabulations (contingency tables) to establish awareness levels. Our study determines those participants who read the emergency instructions booklet are prepared to make an informed decision in the event of a radiological incident. We find college affiliation, educational level, university role, and age significantly related to emergency instruction booklet utilization. We also find gender is significantly linked to overall risk perception regarding a radiological event. Findings support previous research regarding women's higher levels of risk aversion and pessimism involving dangerous new risky technologies and activities like nuclear energy plants. These findings support modifying policy to ensure nuclear facilities assess the efficacy of their warning systems in alerting the public. Furthermore, our findings provide guidance regarding the evaluation of the effectiveness of emergency instruction booklet distribution.


Assuntos
Planejamento em Desastres , Feminino , Humanos , Centrais Nucleares , Reatores Nucleares , Reprodutibilidade dos Testes , Instituições Acadêmicas
9.
Health Phys ; 121(6): 597-601, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34593677

RESUMO

ABSTRACT: In the mid-1970s, American civil defense authorities became increasingly concerned with the potential threat of fission reactor accidents. Research from the Defense Civil Preparedness Agency began to be aimed not just at the ever-present threat of nuclear warfare but also peacetime emergencies as part of a "dual use" philosophy. The Brookhaven National Laboratory received funding to create a prototype radioiodine air sampling system, with multiple publications detailing the creation of the air sampler itself and a special CD V-700 survey meter that accompanied it. In late March 1979, the system found its first operational employment at the reactor accident at Three Mile Island in Pennsylvania. Despite successful use and further study, the BNL Air Sampler was not widely fielded by the federal government. However, lessons learned from its employment and development may be applicable to contemporary radiological emergency response.


Assuntos
Defesa Civil , Radioisótopos do Iodo , Acidentes , Reatores Nucleares , Pennsylvania
10.
J Phys Chem B ; 125(37): 10562-10570, 2021 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-34496565

RESUMO

Despite surging interest in molten salt reactors and thermal storage systems, knowledge of the physicochemical properties of molten salts are still inadequate due to demanding experiments that require high temperature, impurity control, and corrosion mitigation. Therefore, the ability to predict these properties for molten salts from first-principles computations is urgently needed. Herein, we developed and compared a machine-learned neural network force field (NNFF) and a reparametrized rigid ion model (RIM) for a prototypical molten salt LiF-NaF-KF (FLiNaK). We found that NNFF was able to reproduce both the structural and transport properties of the molten salt with first-principles accuracy and classical-MD computational efficiency. Furthermore, the correlation between the local atomic structures and the dynamics was identified by comparing with RIMs, suggesting the significance of polarization of anions implicitly embedded in the NNFF. This work demonstrated a computational framework that can facilitate the screening of molten salts with different chemical compositions, impurities, and additives, and at different thermodynamic conditions suitable for the next-generation nuclear reactors and thermal energy storage facilities.


Assuntos
Temperatura Alta , Reatores Nucleares , Redes Neurais de Computação , Termodinâmica
11.
J Radiol Prot ; 41(4)2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34428754

RESUMO

The safe management and disposal of radioactive waste (RW) arising from the nuclear legacy, as well as newly generated RW, are key problems. Their solution will have important implications for nuclear energy development, the introduction of other radiation technologies, and their public perception. In the framework of the cooperation between the Committee of Atomic and Energy Supervision and Control (CAESC) of the Ministry of Energy of the Republic of Kazakhstan and the Norwegian Radiation and Nuclear Safety Authority (DSA), work has been carried out to analyse the current state of nuclear and radiation safety in the Republic of Kazakhstan. The analysis was based on identifying gaps in national legislation and the assessment of corresponding threats in this area. Proposals for their elimination were developed, taking into account international experience and International Atomic Energy Agency recommendations. Analysis of the current situation in the Republic of Kazakhstan showed that at present the RWs are not properly regulated within an up-to-date regulatory framework. Currently, a list of key by-laws is being developed, which will support the provisions of a new law on RW management, and work is underway to adopt the already developed and drafted regulatory documents. Within the framework of the CAESC-DSA cooperation, the priority tasks established for 2021-2024 include the development of regulatory documents for the rehabilitation of uranium heritage sites, site selection for new nuclear facilities, and the management of nuclear materials for certain types of installations and manufactures. Practice has shown the need to use the advanced international experience and common approaches developed internationally, to develop and apply long-term and reliable solutions for the management of RW and nuclear legacy facilities and territories. The solution of these problems concerns not only scientists, technologists, and employers of the nuclear industry, but requires their cooperation with politicians, regulatory authorities, and the general population. The importance of sharing international experience to understand and solve these challenges is highlighted.


Assuntos
Resíduos Radioativos , Urânio , Gerenciamento de Resíduos , Humanos , Cazaquistão , Reatores Nucleares
13.
14.
J Environ Radioact ; 234: 106622, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33965293

RESUMO

Molten salt reactors (MSRs) are gaining support as many countries look for ways to increase power generation and replace aging nuclear energy production facilities. MSRs have inherently safe designs, are scalable in size, can burn transuranic wastes from traditional solid fuel nuclear reactors, can store excess heat in thermal reservoirs for water desalination, and can be used to produce medical isotopes as part of the real-time liquid-fuel recycling process. The ability to remove 135Xe in real time from the fuel improves the power production in an MSR because 135Xe is the most significant neutron-absorbing isotope generated by nuclear fission. Xenon-135, and other radioactive gases, are removed by sparging the fuel with an inert gas while the liquid fuel is recirculated from the reactor inner core through the heat exchangers. Without effective abatement technologies, large amounts of radioactive gas could be released during the sparging process. This work examines the potential impact of radioxenon releases on samplers used by the International Monitoring System (IMS) to detect nuclear explosions. Atmospheric transport simulations from seven hypothetical MSRs on different continents were used to evaluate the holdup time needed before release of radioxenon so IMS samplers would register few detections. Abatement technologies that retain radioxenon isotopes for at least 120 d before their release will be needed to mitigate the impacts from a molten salt breeder reactor used to replace a nuclear power plant. A holdup time of about 150 d is needed to reduce emissions to the average level of current nuclear power plants.


Assuntos
Poluentes Radioativos do Ar , Monitoramento de Radiação , Poluentes Radioativos do Ar/análise , Isótopos , Centrais Nucleares , Reatores Nucleares , Radioisótopos de Xenônio/análise
15.
J Environ Radioact ; 234: 106623, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34004408

RESUMO

It is imperative to control radio-iodine discharges to atmosphere from nuclear reprocessing plants. Inhalation and ingestion of radio-iodine cause its concentration in the thyroid gland leading to risk of thyroid cancer in humans. Two isotopes of iodine viz. iodine-131 (131I) and iodine-129 (129I) are generated in considerable quantities in the nuclear fuel as fission products in the nuclear reactors. From nuclear reactors, no iodine is released to the atmosphere during normal operations, whereas from spent fuel reprocessing plants, during normal operation, iodine is discharged to the atmosphere, mainly through gaseous discharges. Shortly after the initial periods of reprocessing in 1944, iodine emission control methods were incorporated in the design of reprocessing plants. At the time of spent fuel discharge from reactor, quantity of 131I is high and can contribute radiation dose to humans during reprocessing operations. A delay or cooling period of spent fuel, before reprocessing for a definite number of days can reduce the quantities to below the permissible limits of discharge due to its short half-life of 8 days. 129I has a very long half-life, and is only significant for reprocessing plants of large throughput and high fuel burn-ups. Minimum required de-contamination factor (DF) for iodine for a reprocessing plant can be estimated from the limits of discharge of iodine stipulated by regulatory authority of each country. Though many processes were developed and demonstrated extensively in lab and pilot scale, only a few of these processes were found to be suitable for commercial deployment. This paper reviews systematically the operation experiences and performance characteristics of iodine control methods implemented so far. The review also focus on the effect of integrating various iodine control methods on the main reprocessing operations and thereby facilitate selection of the optimum iodine control method.


Assuntos
Poluentes Radioativos do Ar , Monitoramento de Radiação , Poluentes Radioativos do Ar/análise , Atmosfera , Humanos , Reatores Nucleares
16.
J Environ Radioact ; 234: 106630, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33989844

RESUMO

Advanced nuclear reactor designs and advanced fuel types offer safety features that may reduce environmental consequences in an accident scenario when compared to conventional reactors and fuels. One advanced reactor fuel is tri-structural isotropic (TRISO) fuel particles which are approximately 0.9 mm in diameter. TRISO particle mobility, assuming the particle is unruptured and the encapsulated radionuclides are contained, was explored by a theoretical examination of transport through atmosphere, soil and groundwater, surface water, and non-human biota pathways. TRISO particles are too large and dense to travel in the atmosphere except under extreme conditions. TRISO particles are also too large to penetrate most soil profiles and so cannot be transported to or by groundwater. TRISO particles will settle out of the water column in surface waters and thus the transport will depend on the energy of the water body (e.g., waves or floods). TRISO particles could be transported by non-human biota. The size of TRISO particles could allow them to be intentionally ingested by non-human biota as a gastrolith or mimic something typical in an organism's diet. Generally, TRISO particles will have reduced environmental mobility compared to releases of radionuclides in the event of a conventional nuclear reactor accident. The extent of transport has implications in emergency planning zone designations and other considerations for licensing and deploying TRISO-fueled reactors. Further research and experimental work exploring TRISO particle mobility is required to understand the full environmental mobility of TRISO particles in the environment.


Assuntos
Monitoramento de Radiação , Liberação Nociva de Radioativos , Atmosfera , Reatores Nucleares , Radioisótopos/análise
17.
Health Phys ; 121(2): 117-123, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-33965999

RESUMO

ABSTRACT: Radiation workers are normally exposed to doses resulting from their day-to-day activities. Besides that, background radiation, such as radon, can contribute to the exposure rates. The radionuclide 222Rn is a noble gas belonging to the uranium series, and its indoor concentration in the air depends on the exhalation from surrounding soil and the exhalation from building materials. Radon exhaling from porous building materials containing high uranium concentrations can become a significant exposure factor in areas with limited ventilation. The objective of this study was to evaluate the 222Rn concentrations in the radiochemistry and radiometric laboratories in the nuclear reactor building of the Nuclear Reactor Center (CERPq) located in the Institute of Nuclear and Energy Research (IPEN), São Paulo, Brazil. Measurements were done using a Radon Gas Monitor, model RAD7, equipped with a solid-state alpha detector. A passive method (SSNTD) was also used, consisting of square pieces of C-39 foils (2.5 cm × 2.5 cm) placed within small diffusion chambers. The CR-39 detectors were etched in KOH 30% solution at 80 °C for 5.5 h in a constant-temperature bath. After etching, the detectors were washed, dried, and scanned using a microscope to obtain the track density measurements. The activity concentrations measured with both techniques varied from 52 to 103 Bq m-3 in the studied areas of the CERPq. These values may be compared to the reference level of 100 Bq m-3 established by the World Health Organization to ensure safety environments.


Assuntos
Poluentes Radioativos do Ar , Poluição do Ar em Ambientes Fechados , Monitoramento de Radiação , Radônio , Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Brasil , Humanos , Reatores Nucleares , Monitoramento de Radiação/métodos , Radônio/análise
18.
Yakugaku Zasshi ; 141(4): 557-577, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-33790122

RESUMO

"Retinoid" is the general term for vitamin A derivatives and chemical compounds that act like vitamin A. Vitamin A are composed of four isoprene units and are named according to their terminal functional group, such as retinol (OH, 1), retinal (CHO, 2), and retinoic acid (CO2H, 3). Vitamin A usually refers to retinol. In the past few decades, major advances in research on vitamin A have improved our understanding of its fundamental roles and physiological significance in living cells. In this review, three types of chemical biology studies using vitamin A analogs are described: (1) conformational studies of the chromophore in retinal proteins (rhodopsin, phoborhodopsin, and retinochrome), especially the conformation around the cyclohexene ring; (2) structure-activity relationship studies of retinoic acid analogs to create new signaling molecules for activating nuclear receptors; and (3) development of a new channelrhodopsin with an absorption maximum at longer wavelength to overcome the various demerits of channelrhodopsins used in optogenetics, as well as the stereoselective synthesis of retinoid isomers and their analogs using a diene-tricarbonyliron complex or a palladium-catalyzed cross-coupling reaction between vinyl triflates and stannyl olefins.


Assuntos
Vitamina A/análogos & derivados , Vitamina A/química , Alcenos/química , Catálise , Channelrhodopsins , Cicloexenos/química , Proteínas do Olho/química , Isomerismo , Mesilatos/química , Conformação Molecular , Reatores Nucleares , Paládio/química , Retinoides/síntese química , Retinoides/química , Estereoisomerismo , Relação Estrutura-Atividade , Compostos de Vinila/química , Vitamina A/farmacologia , Vitamina A/fisiologia
19.
Environ Geochem Health ; 43(10): 3967-3975, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33768349

RESUMO

BACKGROUND: The etiology of brain cancer is poorly understood. The only confirmed environmental risk factor is exposure to ionizing radiation. Because nuclear reactors emit ionizing radiation, we examined brain cancer incidence rates in the USA in relation to the presence of nuclear reactors per state. METHODS: Data on brain cancer incidence rates per state for Whites by sex for three age groups (all ages, 50 and older, and under 50) were obtained from cancer registries. The location, number, and type of nuclear reactor, i.e., power or research reactor, was obtained from public sources. We examined the association between these variables using multivariate linear regression and ANOVA. RESULTS: Brain cancer incidence rates were not associated with the number of nuclear power reactors. Conversely, incidence rates per state increased with the number of nuclear research reactors. This was significant for both sexes combined and for males in the 'all ages' category (ß = 0.08, p = 0.0319 and ß = 0.12, p = 0.0277, respectively), and for both sexes combined in the'50 and older' category (ß = 0.18, p = 0.0163). Brain cancer incidence rates for counties with research reactors were significantly higher than the corresponding rates for their states overall (p = 0.0140). These findings were not explicable by known confounders. CONCLUSIONS: Brain cancer incidence rates are positively associated with the number of nuclear research reactors per state. These findings merit further exploration and suggest new opportunities for research in brain cancer epidemiology.


Assuntos
Neoplasias Encefálicas , Reatores Nucleares , Neoplasias Encefálicas/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Sistema de Registros
20.
Appl Radiat Isot ; 172: 109645, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33689941

RESUMO

The newest radioisotope for brachytherapy treatment of prostate cancer is 131Cs (t1/2 = 9.69 d, 100% EC). Generated via electron capture decay of 131Ba (t1/2 = 11.6 d, 100% EC), 131Cs has been used in brachytherapy for prostate cancer since 2004. The 131Ba parent is produced through neutron capture of enriched 130Ba in a nuclear reactor. For large-scale production of 131Ba, an accurate knowledge of production and burnup cross sections of 131Ba are essential. In this paper, we report two group cross sections (thermal and resonance integrals) for 130Ba and 131Ba and a new measure of the half-life of 131Ba. Targets consisting of milligram quantities of enriched 130Ba (∼35%) were irradiated in Oak Ridge National Laboratory's High Flux Isotope Reactor at thermal and resonance neutron fluxes of (1.9-2.1) × 1015 and (5.8-7.0) × 1013 neutrons·cm-2 s-1, respectively, for durations ranging from 3 to 26 days. In addition, cadmium covered samples of 130Ba were irradiated for 1 hour at 12.6% full reactor power (10.7 MW). The yield of 131Ba approaches a saturation value of ∼60 GBq (∼1.6 Ci) per mg of 130Ba for 20 days irradiation at a thermal neutron flux of 1.8 × 1015 n·s-1·cm-2, with a thermal/epithermal ratio of ∼30. Under the above experimental conditions, the two group cross sections of 130Ba are 6.9 ±â€¯0.5 b (thermal, σ0) and 173 ±â€¯7 b (resonance, I0). These values represent the sum of cross sections to metastable and ground states of 131Ba. For 131Ba, the empirically measured thermal cross section is 200 ±â€¯50 b assuming an I0/σ0 of 10. This cross section is reported for the first time. Further, the half-life of 131Ba was remeasured to be 11.657 ±â€¯0.008 d. Lastly, this study also resulted in the co-production of 133Ba (t1/2 = 10.52 y, 100% EC). The experimental yield of 133Ba is ∼370 MBq (∼10 mCi) per mg of 132Ba (thin target) for one cycle irradiation in the High Flux Isotope Reactor, and measured two-group 132Ba cross sections are 7.2 ±â€¯0.2 b and 39.9 ±â€¯1.3 b. These values also represent the sum of cross sections to metastable and ground states of 133Ba.


Assuntos
Radioisótopos de Bário/química , Reatores Nucleares , Radioisótopos de Bário/farmacocinética , Radioisótopos de Bário/uso terapêutico , Braquiterapia/métodos , Meia-Vida , Humanos , Masculino , Nêutrons
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