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1.
J Environ Radioact ; 226: 106345, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33032834

RESUMO

Accelerator mass spectrometry and benzene synthesis coupled with liquid scintillation spectrometry are often used for accurate measurements of 14C activity in the environmental matrices. Thermal oxidation is one of the methods employed for 14C determination in environmental matrices. In this method, the sample is oxidised at high temperature (600-900 °C) to convert carbon species to CO2 and trapped in an amine-based absorber for determining the activity in a liquid scintillation counting (LSC) system. In this study, the performance of a commercially available tube furnace system (pyrolyser), for batch combustion of samples, was evaluated for the determination of 14C specific activity in terrestrial biota samples. Significant improvements over the manufacturer specified method, which is primarily designed for analysis of samples with activity well above the environmental background level, was implemented to achieve accurate determination of 14C specific activity at ambient background level. In the improved method, the CO2 produced from the combustion of the sample was isolated from the combustion products through cryogenic trapping and then absorbed in the absorber (Carbo-Sorb E) through a simple off-line transfer process. This allowed (i) optimisation of CO2 absorption by the absorber (2.2477 g of CO2/10 mL), (ii) achieving good accuracy and precision in the measurements, and a minimum detectable activity value of 13 Bq kg-1C for a counting time of 300 min (7 Bq kg-1C for 1000 min), (iii) avoiding uncertainty associated with the determination of recovery of 14C in the combustion and trapping process, and (iv) elimination of the need for an independent determination of carbon content (%) for expressing the results in terms of 14C specific activity. The method is capable of yielding accurate results with a deviation of <2.4% from the target value for IAEA C3 quality assurance reference material (with a relative standard deviation of 1.40%, and relative error of 0.34%). The combined uncertainty (1σ) associated with the measurements was computed to be 3.4%. Upon optimisation, the suitability of the method for the determination of 14C specific activity in typical terrestrial biota samples of clean air region (region not affected by local anthropogenic sources) and for the quantification of a small increase in the 14C activity above ambient levels in the vicinity of a nuclear power plant is demonstrated.


Assuntos
Monitoramento de Radiação , Carbono , Radioisótopos de Carbono/análise , Centrais Nucleares
2.
J Environ Radioact ; 227: 106509, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33321302

RESUMO

The problem of handling nuclear power plant irradiated structural materials holds one of the central places in the nuclear power industry. High toxic 10Be with a half-life of T1/2 = 1.6 × 106 years is discovered in NPP structural materials after reactor operating. 10Be decays through only electrons' emission. Pure beta emitters are extremely difficult to determine in irradiated structural materials and radioactive waste. We proposed a photoactivation approach for determining the 10Be activity in NPP samples. The proposed method involves determining 9Be and 10B concentrations and subsequent recalculation of 10Be activity formed in 9Be(n, γ)10Be and 10B(n, p)10Be reactions. The amount of 9Be and 10B is determined by samples' photoactivation using an electron accelerator and 9Be(γ, 2n)7Be-, 10B(γ, p2n)7Be-reactions. These reactions' experimental yields were measured for 20, 40, and 55 MeV boundary energies of the bremsstrahlung beam. The proposed technique was tested on samples of ChNPP 2nd unit irradiated structural materials. The technique's calculated error is about 15-20%; the sensitivity is 1 Bq × g-1.


Assuntos
Berílio/análise , Materiais de Construção , Monitoramento de Radiação , Resíduos Radioativos , Elétrons , Centrais Nucleares
3.
Sci Data ; 7(1): 433, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319799

RESUMO

Radiocesium released from the Fukushima Daiichi nuclear power plant (FDNPP) and deposited in the terrestrial environment has been transported to the sea through rivers. To study the long-term effect of riverine transport on the remediation process near the FDNPP, a monitoring project was initiated by the University of Tsukuba. It was commissioned by the Ministry of Education, Culture, Sports, Science, and Technology, and the Nuclear Regulatory Commission in June 2011, and was taken over by the Fukushima Prefectural Centre for Environmental Creation from April 2015. The activity concentration and monthly flux of radiocesium in a suspended form were measured in the project. This provides valuable measurement data to evaluate the impact of the accidentally released radiocesium on residents and the marine environment. It can also be used as verification data in the development and testing of numerical models to predict future impacts.


Assuntos
Radioisótopos de Césio/análise , Acidente Nuclear de Fukushima , Rios/química , Poluentes Radioativos da Água/análise , Monitoramento Ambiental , Japão , Centrais Nucleares
4.
Environ Monit Assess ; 192(10): 666, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33001295

RESUMO

Knowledge of the background activity concentrations of anthropogenic radionuclides before the start of operation of the new nuclear power plant in Belarus, BelNPP, is an issue of great importance for neighbouring countries. In this study, we provide the pilot characterisation of the Lithuanian part of the 30-km zone of the BelNPP, emphasising the forest plants, terrestrial mosses, forest organic and mineral topsoil to describe the preoperational radioecological state of the pine forest ecosystem. Key anthropogenic radionuclides (14C, 3H, 137Cs and 239,240Pu) were analysed. The 14C specific activity varied from 97.80 ± 1.30 to 102.40 ± 0.79 pMC. The 3H specific activity in the tissue-free water tritium form varied from 13.2 ± 2.2 TU to 20.8 ± 2.3 TU, which corresponded to the 3H level of precipitation in this region. The activity concentrations of 239,240Pu in soil and moss samples did not exceed 1 Bq/kg and were mainly due to global fallout after nuclear tests. The 137Cs inventory in the pine forest soils of the Lithuanian part of the BelNPP 30-km zone varied from 930 ± 70 to 1650 ± 430 Bq/m2. High variation of the inventory and uneven distribution in the soil profile conditioned a wide range of 137Сs activity in terrestrial plants from 1.0 ± 0.5 to 40.5 ± 1.8 Bq/kg dry weight. The abundance of microorganisms in different seasons and soil depths do not exceed the natural levels. According to PCA loads, the number of microorganisms and variability of 137Cs specific activity is determined by soil abiotic parameters.


Assuntos
Centrais Nucleares , Poluentes Radioativos do Solo/análise , Ecossistema , Monitoramento Ambiental , Florestas , Solo
5.
PLoS One ; 15(10): e0237264, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002034

RESUMO

The precise evaluation of the potential damage caused by large commercial aircraft crash into civil structures, especially nuclear power plants (NPPs), has become essential design consideration. In this study, impact of Boeing 767 against rigid wall and outer containment building (reinforced concrete) of an NPP are simulated in ANSYS/LS-DYNA by using both force time history and missile target interaction methods with impact velocities ranging from 100 m/s to 150 m/s. The results show that impact loads, displacements, stresses for concrete and steel reinforcement, and damaged elements are higher in case of force time history method than missile target interaction method, making the former relatively conservative. It is observed that no perforation or scabbing takes place in case of 100 m/s impact speed, thus preventing any potential leakage. With full mass of Boeing 767 and impact velocity slightly above 100 m/s, the outer containment building can prevent local failure modes. At impact velocity higher than 120 m/s, scabbing and perforations are dominant. This concludes that in design and assessment of NPP structures against aircraft loadings, sufficient thickness or consideration of steel plates are essential to account for local failure modes and overall structural integrity. Furthermore, validation and application of detail 3D finite element and material models to full-scale impact analysis have been carried out to expand the existing database. In rigid wall impact analysis, the impact forces and impulses from FE analysis and Riera's method correspond well, which satisfies the recommendations of relevant standards and further ensure the accuracy of results in full-scale impact analysis. The methodology presented in this paper is extremely effective in simulating structural evaluation of full-scale aircraft impact on important facilities such as NPPs.


Assuntos
Acidentes Aeronáuticos , Aeronaves , Liberação Nociva de Radioativos , Acidentes Aeronáuticos/estatística & dados numéricos , Códigos de Obras , Simulação por Computador , Materiais de Construção/estatística & dados numéricos , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional , Fenômenos Mecânicos , Modelos Teóricos , Centrais Nucleares , Fenômenos Físicos , Liberação Nociva de Radioativos/prevenção & controle , Liberação Nociva de Radioativos/estatística & dados numéricos , Aço , Colapso Estrutural/prevenção & controle , Colapso Estrutural/estatística & dados numéricos
6.
J Environ Radioact ; 223-224: 106388, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32868095

RESUMO

Radioactive caesium was released during the accident of Fukushima Dai-ichi nuclear power plant (FDNPP) into the surrounding environment. In the current work, radiocaesium micro-particles (CsMPs) and radiocaesium-rich soil particles were selectively separated from soil particles as well as from each other using autoradiography-based procedure. The applied separation scheme is based on water dilution followed by drying of the soil sample prior to imaging plate autoradiography. The SEM/EDS investigation of the individual CsMPs showed that these particles have a silicate glass structure and vary in shape with a diameter less than 10 µm. For the first time, a two-stage formation mechanism was suggested for a CsMP based on shape and structure heterogeneity of its two parts. Perfect spherical core might be formed in the first stage with a remarkable lower content of Al, and relatively higher concentrations of Si and K than an outer angulated structure, which might be attached to the core sphere during a late stage. The radiocaesium-rich soil particles have bigger size than CsMPs and have a plate-like structure with cleavages inside the grains, which suggest that these particles might be a weathered biotite. The average radioactivity ratio of 134Cs/137Cs (dated March 11, 2011) in the investigated particles was found to be 1.05 ± 0.01, which confirmed that the radiocaesium in CsMPs and in the contaminated soil particles has the same source of origin, which could be unite 3 of FDNPP.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Radioisótopos de Césio/análise , Japão , Centrais Nucleares , Solo , Poluentes Radioativos do Solo/análise
7.
J Environ Radioact ; 223-224: 106373, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32873399

RESUMO

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, immediate soil and vegetation sampling were conducted according to the action plan of nuclear emergency monitoring; however, analysing the monitoring dataset was difficult because the sampling protocols were not standardised. In this study, the sampling protocols applied just after the FDNPP accident were reviewed, and the monitoring data were analysed. The detailed protocols and results can provide a sound basis for guidelines of soil and vegetation sampling for nuclear emergency monitoring. The activity concentrations of 137Cs and 131I in weed samples measured immediately after the FDNPP accident were related to the air dose rate at 1 m. Consequently, vegetation sampling is recommended when the additional dose rate (above background) is higher than 0.1 µSv/h. To enhance the efficiency of a protective response in the case of a nuclear accident, predetermined sampling points for soil and vegetation sampling should be considered in the preparedness plan for nuclear emergencies. Furthermore, sampling and analytical measurement capacities (time, people, cost) during the early phase after nuclear emergencies need to be considered in the preparedness and action plan, and sampling and measurement exercises are highly recommended.


Assuntos
Defesa Civil , Acidente Nuclear de Fukushima , Monitoramento de Radiação , Radioisótopos de Césio/análise , Japão , Centrais Nucleares , Solo , Poluentes Radioativos do Solo/análise
8.
J Environ Radioact ; 222: 106348, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892904

RESUMO

This study examined the temporal variations in radiocesium concentration associated with sinking particles in the northeastern Japan Sea between September 2010 and July 2012. We analyzed sediment trap samples from this period after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011. Cesium-134 was detected in samples collected between May and July 2011 at a depth of 1100 m (4.2-11 mBq g-dry-1) but not in other periods at 1100 m or deeper (3100 and 3500 m). These results confirmed the deposition of FDNPP-derived radiocesium on the surface water in the late April 2011, which rapidly sank with sinking particles to a depth of at least 1100 m, in the northeastern Japan Sea, about 40 days after the deposition in the North Pacific. If FDNPP-derived 137Cs was excluded, no seasonal changes were detected in the 137Cs activity concentration of the sinking particles, and the 137Cs activity concentration of the particles increased with increasing depth. Judging from the concentration of 137Cs of sinking particle and seasonal variation of total mass flux and organic matter content, the lithogenic particle seems to be important for radiocesium associated with sinking particles. These data also strongly suggest a difference in sinking features of particles between 2010-2011 and 2011-2012 deployments. Due to the existence of benthic front, shallow water (1100 m) and deep water (3500 m) are separated during 2010-2011 deployment, but in the winter of 2011-2012, this front disappeared and the particles in surface water seem to have sunk to the depth of 3100 m. The sinking velocity of the particles at 1100 m was estimated to be 33-62 m day-1, with a mean sinking velocity of 43 m day-1. These values were comparable to those estimated at depths shallower than 1000 m in the North Pacific after the FDNPP accident, or in the Mediterranean, North, and Black Seas after the Chernobyl accident.


Assuntos
Radioisótopos de Césio , Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos da Água , Mar Negro , Radioisótopos de Césio/análise , Japão , Centrais Nucleares
9.
J Environ Radioact ; 222: 106356, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32892908

RESUMO

Predictions of the atmospheric dispersion of radionuclides accidentally released from a nuclear power plant are influenced by two large sources of uncertainty: one associated with the meteorological data employed, and one with the source term, i.e. the temporal evolution of the amount and physical and chemical properties of the release. A methodology is presented for quantitative estimation of the variability of the prediction of atmospheric dispersion resulting from both sources of uncertainty. The methodology, which allows for efficient calculation, and thus is well suited for real-time assessment, is applied to a hypothetical accidental release of radionuclides.


Assuntos
Poluentes Radioativos do Ar , Monitoramento de Radiação , Liberação Nociva de Radioativos , Modelos Teóricos , Centrais Nucleares , Incerteza
10.
PLoS One ; 15(9): e0239296, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32931520

RESUMO

Following the Fukushima Daiichi Nuclear Power Plant accident in March 2011, radionuclides such as iodine-131, cesium-134 and cesium-137 were released into environment. In this study, we collected wild mushrooms from the Kawauchi Village of Fukushima Prefecture, located less than 30 km southwest of the Fukushima nuclear power plant, to evaluate their radiocesium (134Cs+137Cs) concentrations and the risk of internal radiation exposure in local residents. 342 mushroom samples were collected from 2016 to 2019. All samples were analysed for radiocesium content by a high-purity germanium detector. Among 342 mushroom samples, 260 mushroom samples (76%) were detected the radiocesium exceeding the regulatory limit of radiocesium (100 Bq/kg for general foods in Japan). The median of committed effective dose from ingestion of wild mushrooms was in the range of 0.015-0.053 mSv in 2016, 0.0025-0.0087 mSv in 2017, 0.029-0.110 mSv in 2018 and 0.011-0.036 mSv in 2019 based on the assumption that Japanese citizens consumed wild mushrooms for 1 year. Thus, our study showed that although radiocesium is still detected in mushrooms collected in Kawauchi village even after 5 to 9 years later, the committed effective dose due to consuming mushrooms was lower than 1 mSv per year. Long-term comprehensive follow-up should monitor radiocesium concentrations in wild mushrooms to support the recovery of the community after the nuclear disaster.


Assuntos
Agaricales/efeitos da radiação , Radioisótopos de Césio/isolamento & purificação , Agaricales/química , Radioisótopos de Césio/toxicidade , Contaminação Radioativa de Alimentos/estatística & dados numéricos , Acidente Nuclear de Fukushima , Humanos , Japão , Centrais Nucleares , Monitoramento de Radiação
11.
J Environ Radioact ; 222: 106359, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32750599

RESUMO

Most of environmental monitoring programs include measurements of the air dose rates and the radionuclides activity concentration in plants. Both these parameters depend on deposition density of radionuclides. Therefore, measurements of one parameter can (with some supplementary information) be used as an indicator for the other parameter. After the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, the Emergency Operation Centre (EOC) operated by the Environmental Radioactivity Monitoring centre of Fukushima and Ministry of Agriculture, Forestry and Fisheries (MAFF) of Japan carried out large sampling programme over different distances from the NPP. The sampling programme was focused on the usage of the weed leaves as a proxy for the prediction of radionuclide transfer to some cultivated plants. The MAFF monitoring programme in 2011-2016 was addressed mainly to agricultural crops. In both cases, the air dose rates were measured at the sites of the sampling. The paper addresses the assessments of relationship between radionuclide activities concentrations in plants and ambient dose rates. The time-dependent relationships were quantified based on weed, buckwheat, brown rice and soybean data obtained in 2011-2016. The recommendations on optimizing emergency sampling programmes based on use of the data of ambient dose rates are also presented.


Assuntos
Agricultura , Acidente Nuclear de Fukushima , Plantas Comestíveis , Monitoramento de Radiação , Radioisótopos , Radioisótopos de Césio , Japão , Centrais Nucleares , Plantas Comestíveis/química , Radioisótopos/análise
12.
J Environ Radioact ; 222: 106347, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32755760

RESUMO

Data on reduction of radioactivity in plants are highly important for making decision on emergency response and remediation of contaminated areas. Dynamics of the 131I and 137Cs concentrations in the weed leaves sampled in the areas affected by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in Japan was assessed for the period March-December 2011. The effective half-lives for 131I and 137Cs of 3.8-4.2 days and 7.1-13.3 days in the weed leaves were calculated for the first two months after the deposition. The approach for assessment of the aggregated transfer factors based on the ambient dose equivalent rate was suggested and validated. The geometric means of the soil to the weed leaves aggregated transfer factors were estimated for June-December 2011. Soil to crop 137Cs- concentration ratios (buckwheat, brown rice and soybean) were estimated for 2011-2016. Soil to crop concentration ratios were found to decrease in the order of soybean > buckwheat > brown rice. The effective half-lives for 137Cs in these crops were estimated to be between 1 and 2.5 years for the period 2011 2016, and longer than 5-7 years after 2016. It was found that these data comply with the Chernobyl related data obtained for similar conditions and complement of international documents on radionuclide transfer in agricultural environment such as the IAEA TRS 472.


Assuntos
Radioisótopos de Césio , Acidente Nuclear de Fukushima , Monitoramento de Radiação , Radioisótopos de Césio/análise , Japão , Centrais Nucleares , Folhas de Planta
13.
PLoS One ; 15(8): e0237605, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804934

RESUMO

The vertical distribution of radiocarbon (14C) was examined in the bottom sediment core, taken from Lake Druksiai, which has served as a cooling pond since 1983 for the 26 years of the Ignalina Nuclear Power Plant (INPP) operation using two RBMK-1500 reactors (Russian acronym for"Channelized Large Power Reactor"). 14C specific activity was measured in alkali-soluble and -insoluble fractions of the sediment layers. Complementary measurements of the 210Pb and 137Cs activity of the samples provided the possibility to evaluate the date of every layer formation, covering the 1947-2013 period. In addition, 14C distribution was examined in the scales of pelagic fish caught between 1980 and 2012. Our measurements reveal that, during the period 1947-1999, the radiocarbon specific activity in both fractions exhibits a parallel course with a difference of 5 ± 1 pMC (percent of modern carbon) being higher in alkali-soluble fraction, although 14C specific activity in both fractions increased by 11.4-13.6 pMC during the first 15 years of plant operation. However, during the 2000-2009 period, other than previously seen, a dissolved inorganic carbon (DIC) → aquatic primary producers → sediments 14C incorporation pattern occurred, as the radiocarbon specific activity difference between alkali-soluble and -insoluble fractions reached 94, 25, and 20 pMC in 2000, 2006, and 2008, respectively. Measurements in different sediment fractions allowed us to identify the unexpected organic nature of 14C contained in liquid effluences from the INPP in 2000-2009. The discrepancy between 14C specific activity in fish scales samples and DIC after 2000 also confirmed the possibility of organic 14C contamination. Possible reasons for this phenomenon might be industrial processes introduced at the INPP, such as the start of operation of the cementation facility for spent ion exchange resins, decontamination procedures, and various maintenance activities of reactor aging systems and equipment.


Assuntos
Radioisótopos de Carbono/análise , Sedimentos Geológicos/análise , Lagos/química , Monitoramento de Radiação/métodos , Animais , Radioisótopos de Césio/análise , Peixes/crescimento & desenvolvimento , Radioisótopos de Chumbo/análise , Lituânia , Centrais Nucleares
14.
Artigo em Inglês | MEDLINE | ID: mdl-32759835

RESUMO

Commissioning workers at nuclear power plants have long been ignored in previous studies, although their performance is closely related to the overall safety of plants. This study aimed to explain and predict three types of behavior, i.e., errors, violations, and safety participation, of commissioning workers, under the general framework of the theory of planned behavior (TPB) and by considering organization and planning factors. The validity of the model was evaluated with a sample of 167 commissioning workers who completed a self-reported questionnaire. The results showed that perceived behavioral control, along with organization and planning, significantly affected all types of behavior. It was also found that violations and errors were a direct result of attitude. Besides, errors were predicted by subjective norm; unexpectedly, this occurred in a positive way. These findings revealed the underlying mechanisms for the development of errors, violations, and safety participation among commissioning workers and provided practical implications for safety improvement at the commissioning workplace.


Assuntos
Comportamentos Relacionados com a Saúde , Centrais Nucleares , Gestão da Segurança , Atitude , Humanos , Intenção , Inquéritos e Questionários , Local de Trabalho
15.
J Environ Radioact ; 222: 106341, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32778530

RESUMO

Micro-SWIFT SPRAY (MSS) is a 3D Lagrangian particle dispersion model that maintains a good balance between accuracy and computational cost. However, its capabilities for air dispersion modeling in the presence of both complex topography and high building densities have not been investigated for nuclear emergency response. In this study, MSS is systematically evaluated against two wind tunnel experiments that simulate a typical Chinese nuclear power plant with the above two features. The MSS predictions are compared with both 2D horizontal and vertical measurements. Sensitivity studies are performed with respect to the particle number, the lower bound of the turbulence intensity, and the horizontal and vertical grid size. The results demonstrate that ground-level predictions of both wind and radionuclide concentrations are in satisfactory agreement with the measurements under optimized parameter values. The vertical predictions exhibit site-dependent accuracy, but generally consistent tendencies. The default lower bound of the turbulence intensity in MSS may be insufficient for reproducing the correct plume width observed in the wind tunnel experiments. An increased lower bound is suggested to solve this problem. In addition, artificially high concentrations may arise near steep slopes if large horizontal/vertical grid sizes are used. Suitable parameters for preventing this problem are also provided.


Assuntos
Poluentes Atmosféricos , Monitoramento de Radiação , Modelos Teóricos , Centrais Nucleares , Radioisótopos
16.
J Environ Radioact ; 222: 106340, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32763727

RESUMO

As the number of nuclear power plants (NPPs) being decommissioned increases internationally, many issues are being raised. One such issue is related to site soil analyses for the determination of residual risk for license termination. In a typical site-cleanup analysis, the majority of soil samples at the site are at or below the detection limit (BDL). Conventional approaches to managing BDL data are to simply ignore or substitute the data with a value of zero or the detection limit itself. However, these approaches are statistically biased, limiting their usefulness. Within the environmental science community, the issue of how to treat BDL data has been examined by a number of investigators. This study reviewed the issue of BDL data in nuclear decommissioning using the analytical methods suggested by studies in the environmental science, including the Kaplan-Meier method, robust regression on order statistics, and maximum likelihood estimation. The use of these methods to handle BDL data was examined using a case study with respect to its potential impact on dose/risk assessment, the soil volume removal estimate, and the associated costs. The case study was based on the Colorado School of Mines Research Institute's site soil data. Our analysis included the consideration of the uncertainties associated with residual dose/risk, waste soil volume estimation, and costs. An uncertainty analysis was conducted using a Latin hypercube sampling approach. Results showed that using BDL data can have a large impact on the estimation of dose/risk, waste volume, and waste disposal cost of a NPP decommissioning project.


Assuntos
Centrais Nucleares , Monitoramento de Radiação , Poluentes Radioativos do Solo , Colorado , Limite de Detecção , Medição de Risco , Poluentes Radioativos do Solo/análise
17.
PLoS One ; 15(8): e0236997, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32756579

RESUMO

The aim of this study was to clarify the factors affecting anxiety among administrative officers working within the urgent protective action planning zone of a nuclear power station to establish an effective education program on radiation and its health effects to help reduce anxiety in residents. We included 1,181 officers who worked at local authorities within the urgent protective action planning zone of Sendai Nuclear Power Station in Kagoshima Prefecture, Japan. Logistic regression analysis revealed that female sex (odds ratio = 2.33), working more than 21 years as an administrative officer (odds ratio = 1.49), lack of participation in training on nuclear disasters (odds ratio = 1.42), and not knowing the three principles of radiation protection (odds ratio = 1.36) were independently associated with anxiety among administrative officers working within the urgent protective action planning zone. It is important to establish an effective education program on radiation and its health effects for administrative officers working within the urgent protective action planning zone to reduce anxiety in residents.


Assuntos
Ansiedade/etiologia , Acidente Nuclear de Fukushima , Centrais Nucleares , Exposição Ocupacional , Exposição à Radiação , Adulto , Feminino , História do Século XXI , Humanos , Japão , Masculino , Centrais Nucleares/história , Exposição Ocupacional/história , Saúde do Trabalhador , Exposição à Radiação/história , Inquéritos e Questionários
18.
PLoS One ; 15(7): e0236640, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32716980

RESUMO

Japanese firefighting organisations are essentially run as village, town, or city units. The Great Hanshin Earthquake of 1995 led to the establishment of emergency support teams to ensure rapid action in response to disasters beyond the capacities of local fire departments. The 2011 Great East Japan Earthquake involved both a tsunami and a radiation disaster caused by a nuclear reactor meltdown, underscoring the need for responses in complex disasters. This study aimed to assess Nagasaki Prefecture firefighters' preparedness for, awareness of, and anxiety regarding radiation disaster response with the aim of elucidating the factors affecting individuals' decisions to accept or reject assignment to a radiation disaster response team. A questionnaire survey was carried out with 1,122 firefighters in three firefighting departments in Nagasaki Prefecture, which does not have nuclear power plants. In total, 920 questionnaires were returned, and the 784 that were valid were analysed. Among the participants, 39% replied that they would have no difficulty accepting assignment to a radiation disaster response team; most of them were under 30 years old and unmarried. This group also included significantly higher percentages of participants who were confident about radiation disaster response or, if anxious, believed things would turn out fine, as well as those who replied that they were able to use the necessary equipment. Furthermore, this group had significantly higher percentages of participants who replied that they would definitely participate in seminars and those who replied that their level of preparedness for radiation disasters was sufficient. The willingness to be assigned to a radiation disaster response team was linked to confidence about radiation disaster response and about handling materials and/or equipment. Therefore, it is considered that measures to increase firefighters' confidence regarding response to radiation disasters will be linked to more proactive measures if and when such disasters occur.


Assuntos
Conscientização , Bombeiros/psicologia , Exposição à Radiação , Adulto , Desastres , Humanos , Japão , Modelos Logísticos , Pessoa de Meia-Idade , Centrais Nucleares , Inquéritos e Questionários
19.
Artigo em Inglês | MEDLINE | ID: mdl-32604809

RESUMO

After the Fukushima Daiichi Nuclear Power Plant accident in March 2011, residents perceived a radiation exposure risk. To address the concerns about radiation exposure and the subsequent effects on their health, we developed the gatekeeper training program for radiation health anxiety and mental health issues. The program consisted of a presentation and roleplay, with educational objectives to the increase knowledge and understanding around radiation health anxiety, alcoholism, depression, and suicide. Twenty-six counselors participated in the program as a single-arm intervention. To measure the outcomes, the subjects reported self-confidence when they counselled with residents with radiation health anxiety and other mental health issues. Comparing the answers to pre- and 2-month follow-up surveys, the confidence levels were higher after 2 months than at baseline, especially for the question "How confident are you at supporting a resident with mental health issues?", which showed the largest increase (p < 0.001). Regarding radiation health anxiety the questions "Can you communicate coping skills to a resident with radiation health anxiety?" (p = 0.007) and "Can you refer a resident with radiation health anxiety to professionals who can cope appropriately?" (p = 0.016) showed significant increases in their confidence levels. This program could be useful for on-going health activities and future nuclear disasters.


Assuntos
Ansiedade , Aconselhamento , Acidente Nuclear de Fukushima , Centrais Nucleares , Exposição à Radiação , Lesões por Radiação , Adulto , Idoso , Aconselhamento/educação , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Lesões por Radiação/psicologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-32722235

RESUMO

Assessing workers' safety and health during the decommissioning of nuclear power plants (NPPs) is an important procedure in terms of occupational radiation exposure (ORE). Optimizing the radiation exposure through the "As Low As Reasonably Achievable (ALARA)" principle is a very important procedure in the phase of nuclear decommissioning. Using the VISIPLAN 3D ALARA planning tool, this study aimed at assessing the radiological doses to workers during the dismantling of the reactor pressure vessel (RPV) at Kori NPP unit 1. Fragmentation and segmentation cutting processes were applied to cut the primary component. Using a simulation function in VISIPLAN, the external exposure doses were calculated for each work operation. Fragmentation involved 18 operations, whereas segmentation comprised 32 operations for each fragment. Six operations were additionally performed for both hot and cold legs of the RPV. The operations were conducted based on the radioactive waste drum's dimensions. The results in this study indicated that the collective doses decreased as the components were cut into smaller segments. The fragmentation process showed a relatively higher collective dose compared to the segmentation operation. The active part of the RPV significantly contributed to the exposure dose and thus the shielding of workers and reduced working hours need to be considered. It was found that 60Co contained in the stainless steel of the reactor vessel greatly contributed to the dose as an activation material. The sensitivity analysis, which was conducted for different cutting methods, showed that laser cutting took a much longer time than plasma cutting and contributed higher doses to the workers. This study will be helpful in carrying out the occupational safety and health management of decommissioning workers at Kori NPP unit 1 in the near future.


Assuntos
Exposição Ocupacional , Saúde do Trabalhador , Monitoramento de Radiação , Resíduos Radioativos , Humanos , Centrais Nucleares , Exposição Ocupacional/análise , Doses de Radiação
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