The Fukushima Accident

2011 ◽  
pp. 189-207 ◽  
Author(s):  
Peter Ladkin
Keyword(s):  
Author(s):  
Valentina Drozd ◽  
Vladimir Saenko ◽  
Daniel I. Branovan ◽  
Kate Brown ◽  
Shunichi Yamashita ◽  
...  

The incidence of differentiated thyroid cancer (DTC) is steadily increasing globally. Epidemiologists usually explain this global upsurge as the result of new diagnostic modalities, screening and overdiagnosis as well as results of lifestyle changes including obesity and comorbidity. However, there is evidence that there is a real increase of DTC incidence worldwide in all age groups. Here, we review studies on pediatric DTC after nuclear accidents in Belarus after Chernobyl and Japan after Fukushima as compared to cohorts without radiation exposure of those two countries. According to the Chernobyl data, radiation-induced DTC may be characterized by a lag time of 4–5 years until detection, a higher incidence in boys, in children of youngest age, extrathyroidal extension and distant metastases. Radiation doses to the thyroid were considerably lower by appr. two orders of magnitude in children and adolescents exposed to Fukushima as compared to Chernobyl. In DTC patients detected after Fukushima by population-based screening, most of those characteristics were not reported, which can be taken as proof against the hypothesis, that radiation is the (main) cause of those tumors. However, roughly 80% of the Fukushima cases presented with tumor stages higher than microcarcinomas pT1a and 80% with lymph node metastases pN1. Mortality rates in pediatric DTC patients are generally very low, even at higher tumor stages. However, those cases considered to be clinically relevant should be followed-up carefully after treatment because of the risk of recurrencies which is expected to be not negligible. Considering that thyroid doses from the Fukushima accident were quite small, it makes sense to assess the role of other environmental and lifestyle-related factors in thyroid carcinogenesis. Well-designed studies with assessment of radiation doses from medical procedures and exposure to confounders/modifiers from the environment as e.g., nitrate are required to quantify their combined effect on thyroid cancer risk.


2020 ◽  
Vol 108 (10) ◽  
pp. 799-808
Author(s):  
Mostafa M. Hamed ◽  
Mahmoud M. S. Ali ◽  
Aly A. Helal

AbstractRemoval of 137Cs radionuclides from the environment has engrossed the concern of researchers after Fukushima accident. The leakage of radioactive cesium ions can lead up to surface and groundwater contamination, and this leads to pollution of drinking water sources. In this work, corchorus olitorius stalks has been used as a novel precursor for production of low-cost mesoporous activated carbon (Meso-AC) and HNO3/H2O2-modified Meso-AC (m-Meso-AC). The physicochemical properties of all adsorbents were evaluated. The influences of sorption parameters and presence of some ligands (humic acid, fulvic acid, and EDTA) on the sorption of 137Cs were studied. The maximum 137Cs capacity of m-Meso-AC was found to be 58.74 mg/g. Efficiency of the new adsorbent to remove 137Cs radionuclides from natural waters (tap, river, and groundwater) was investigated. The studies showed that new adsorbent could be used as promising material for the retention of 137Cs from real radioactive waste and natural water samples.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hikaru Miura ◽  
Yuichi Kurihara ◽  
Masayoshi Yamamoto ◽  
Aya Sakaguchi ◽  
Noriko Yamaguchi ◽  
...  

2019 ◽  
Vol 54 (4) ◽  
pp. 241-246 ◽  
Author(s):  
J.F. Bottollier-Depois ◽  
E. Allain ◽  
G. Baumont ◽  
N. Berthelot ◽  
G. Darley ◽  
...  

After the Fukushima accident, initiatives emerged offering the public the possibility to realise measurements of the radioactivity in the environment with various devices and to share data and experiences through collaborative tools. The objective of the OpenRadiation project is to offer the public the opportunity to perform measurements of the radioactivity using connected dosimeters on smartphones. The challenge is to operate such a system on a sustainable basis in normal situations and in order to be useful in an emergency situation. In normal situations, this project is based on a collaborative approach including pedagogical activities. In case of emergency situation, data from the field will be available in “real time” providing an opportunity for the emergency management and the communication with the public. The practical objectives are to develop i) a website centralising measurements using various dosimeters, providing dose rate maps with raw and filtered data and offering dedicated areas for specific projects and exchanges about data and ii) a dosimetric app using a connected dosimeter. This project is conducted within a partnership between organisms’ representative of the scientific community and associations to create links with the public.


2013 ◽  
Vol 55 ◽  
pp. 17-21 ◽  
Author(s):  
M. Baba
Keyword(s):  

Author(s):  
Yabing Li ◽  
Lili Tong ◽  
Xuewu Cao

In order to satisfy the higher safety requirements after the Fukushima Accident, in-vessel retention (IVR) strategy is suggested to be a measure for the improvement for the operating 2nd generation Pressurized Water Reactor (PWR). In this paper, a design of passive cavity flooding system isproposed for the 2nd generation modified PWR with reference to the design of in-containment refueling water storage tank (IRWST)for AP1000, and the IVR assessmentis evaluated with the risk oriented accident analysis methodology (ROAAM). Seven representational accident sequences are selected for the IVR assessment and analyzed by lumped-parameter safety analysis computer code. Accident analysis focuses on four key parameters forthe assessment, that is, decay power, zirconium oxidation fraction, and both the mass of oxidic pool and metal layer. The values of them are obtained through analysis and used for the assessment. The probability density distributions of those parameters are determined by combining the analysis results and engineering judgment. The success probability of IVR from the viewpoint of thermal failure is predicted using a program written by the Matlab code. Furthermore, some sensitivity analysis and parametric studies are investigated to support the assessment. The assessment result shows that the success probability of the cavity injection system is higher than 99%. Detail analysis about system reliability and feasibility is needed for further work.


Author(s):  
Michio Murakami ◽  
Takao Nirasawa ◽  
Takao Yoshikane ◽  
Keisuke Sueki ◽  
Kimikazu Sasa ◽  
...  

Evaluation of radiation exposure from diet is necessary under the assumption of a virtual accident as a part of emergency preparedness. Here, we developed a model with complete consideration of the regional food trade using deposition data simulated by a transport model, and estimated the dietary intake of radionuclides and the effectiveness of regulation (e.g., restrictions on the distribution of foods) after the Fukushima accident and in virtual accident scenarios. We also evaluated the dilution factors (i.e., ratios of contaminated foods to consumed foods) and cost-effectiveness of regulation as basic information for setting regulatory values. The doses estimated under actual emission conditions were generally consistent with those observed in food-duplicate and market-basket surveys within a factor of three. Regulation of restricted food distribution resulted in reductions in the doses of 54–65% in the nearest large city to the nuclear power plant. The dilution factors under actual emission conditions were 4.4% for radioiodine and 2.7% for radiocesium, which are ~20 times lower than those used in the Japanese provisional regulation values after the Fukushima accident. Strict regulation worsened the cost-effectiveness for both radionuclides. This study highlights the significance and utility of the developed model for a risk analysis of emergency preparedness and regulation.


Author(s):  
Marco Pellegrini ◽  
Giulia Agostinelli ◽  
Hidetoshi Okada ◽  
Masanori Naitoh

Steam condensation is characterized by a relatively large interfacial region between gas and liquid which, in computational fluid dynamic (CFD) analyses, allows the creation of a discretized domain whose average cell size is larger than the interface itself. For this reason generally one fluid model with interface tracking (e.g. volume of fluid method, VOF) is employed for its solution in CFD, since the solution of the interface requires a reasonable amount of cells, reducing the modeling efforts. However, for some particular condensation applications, requiring the computation of long transients or the steam ejected through a large number of holes, one-fluid model becomes computationally too expensive for providing engineering information, and a two-fluid model (i.e. Eulerian two-phase flow) is preferable. Eulerian two-phase flow requires the introduction of closure terms representing the interactions between the two fluids in particular, in the condensation case, drag and heat transfer. Both terms involve the description of the interaction area whose definition is different from the typical one adopted in the boiling analyses. In the present work a simple but effective formulation for the interaction area is given based on the volume fraction gradient and then applied to a validation test case of steam bubbling in various subcooling conditions. It has been shown that this method gives realistic values of bubble detachment time, bubble penetration for the cases of interest in the nuclear application and in the particular application to the Fukushima Daiichi accident.


Author(s):  
Wei Gao ◽  
Guofeng Tang ◽  
Jingyu Zhang ◽  
Qinfang Zhang

Seismic risk of nuclear power plant has drawn increasing attention after Fukushima accident. An intensive study has been carried out in this paper, including sampling of component and structure fragility based on Monte Carlo method, fragility analysis on system or plant level, convolution of seismic hazard curves and fragility curves. To derive more accurate quantification results, the binary decision diagram (BDD) algorithm was introduced into the quantification process, which effectively reduces the deficiency of the conventional method on coping with large probability events and negated logic. Seismic Probabilistic Safety Analysis (PSA/PRA) quantification software was developed based on algorithms discussed in this paper. Tests and application has been made for this software with a specific nuclear power plant seismic PSA model. The results show that this software is effective on seismic PSA quantification.


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