TRANSFORMATION OF RADIOCESIUM SPECIATION IN PONDS AT THE VICINITY OF FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT AND ITS DYNAMICS IN “SEDIMENTS-WATER” SYSTEM

2021 ◽  
pp. 38-45
Author(s):  
A. V. Konoplev ◽  
◽  
Y. Wakiyama ◽  
T. Wada ◽  
M. Ivanov ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Water System ◽  
137Cs Activity ◽  
Exclusion Zone ◽  
Activity Concentrations ◽  
Dam Reservoirs ◽  
Radiocesium Interception Potential ◽  
The Subject

The paper is concerned with the results of 137Cs monitoring in the irrigation ponds of the Okuma town in the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) exclusion zone. The 137Cs activity concentrations in the ponds appeared to be higher than those in the rivers and dam reservoirs in the region. The study has revealed a trend for a decline in 137Cs activity concentrations, both particulate and dissolved. The rate of particulate 137Cs decline was much higher than that of dissolved. The total distri- bution coefficient Kd (137Cs) in the suspended sediment-water system in the studied ponds was decreasing in time with the rate constant of 0.12-0.18 year-1. Assuming that the decrease in Kd is associated with decomposition of hot glassy particles, the time scale of 137Cs leaching from them in these water bodies was estimated to be 5-8 years. These estimates are consistent with the findings of recent laboratory experiments on the subject. With respect to seasonal variations, the highest levels of dissolved 137Cs in the studied ponds were observed from June to October as a function of specific pond and monitoring year. Based on data about 137Cs speciation in the bottom sediment top layer of the ponds and its distri- bution in the sediment-water system, the exchangeable radiocesium interception potential RIPex(K) for the ponds sediments was estimated to be 1650-2250 mg-eq/kg, which is within the range of values measured by laboratory studies.

scholarly journals STUDIES OF 137CS TRANSFER IN SOIL‐FERN SYSTEM

2005 ◽  
Vol 13 (3) ◽  
pp. 97-102 ◽  
Author(s):  
Donatas Butkus ◽  
Marina Konstantinova
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Transfer Factor ◽  
Nuclear Power ◽  
Activity Concentration ◽  
Root Systems ◽  
137Cs Activity ◽  
Chernobyl Nuclear Power Plant ◽  
Activity Concentrations ◽  
Better Than

Fern accumulates radionuclides in abundance, including 137Cs. Tranfer of 137Cs and 40K in plants which have different root systems (fern or grass), or have no roots at all (moss) was compared. Samplings were performed in regions contaminated with 137Cs after Chernobyl Nuclear Power Plant (ChNPP) accident in 1994 and 1997–2000. The male fern (Dryopteris filix‐mas) most prevailing in Lithuania was studied. Fern accumulates 137Cs more effectively than grass or moss. The average 137Cs activity concentration in fern is 180±60 Bq kg−1 and the transfer factor is 0,074 m2kg−1. The fern stipe accumulates 137Cs most of all (200±90 Bqkg‐1), the transfer factor is 0,087 m2 kg−1. Accumulation of 137Cs is influenced by the content of K in the soil. 137Cs and 40K activity concentrations in fern are higher than those in the soil what shows that fern accumulates 137Cs better than 40K. Fern can clean the soil because this plant accumulates radionuclides in its stipe rather than roots.

scholarly journals Large Carnivores of the Chernobyl Nuclear Power Plant Exclusion Zone

2012 ◽  
Vol 46 (3) ◽  
pp. e-21-e-28 ◽  
Author(s):  
M. Shkvyria ◽  
D. Vishnevskiy
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Species Composition ◽  
Nuclear Power ◽  
Chernobyl Nuclear Power Plant ◽  
Large Carnivores ◽  
Exclusion Zone ◽  
Animal Group ◽  
Large Predators

Large Carnivores of the Chernobyl Nuclear Power Plant Exclusion Zone During nine years observations on large carnivores of Exclusion Zone have been carried out. Species composition and the number of large predators in the Exclusion Zone correspond to the regional conditions. The presence of bears and permanent stay of the lynx in the Exclusion Zone was confirmed. Six wolf packs were counted. The use of an anthropogenically transformed areas, the shift of the daily regime of activity and characteristics of the diet are the most specific features of this animal group.

Concept of Standard System Based on China Current Nuclear Power Construction

2014 ◽  
Author(s):  
Yuelan Yan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Standard System ◽  
Power Development ◽  
Power Construction ◽  
Nuclear Power Development ◽  
System Method ◽  
The Subject ◽  
Power Standard

Since introduce different technical routes, during decades of nuclear power development in our country, the French RCC series standards, American ASME standards and Russian standards are adopted, which led to the current various standards exist in their own way. To promote the building of nuclear power standards system in China, in the year of 2012, important research subject “the research on the standard system of advanced nuclear power in China” has been carried out and subject “nuclear power construction and commissioning” is one of it.. By digestion and absorption of four oversea AP1000 units of Sanmen nuclear power plant in Zhejiang province and Haiyang nuclear power plant in Shandong province, the building of standard system during nuclear power construction suitable to our national condition is studied, including the system frame and composition standards, building standard system method during construction, namely through research and example to present what kind of standard system is suitable for China standard system during construction, and what kind of method or design is used to obtain and maintain such system. The thesis is to promote the subject research methods based on examples to build China’s nuclear power standard system.

scholarly journals SOME ISSUES OF LIFE ACTIVITIES OF POPULATION IN THE CHORNOBYL EXCLUSION ZONE IN UKRAINE

2021 ◽  
Vol 26 ◽  
pp. 141-161
Author(s):  
N. Gunko ◽  
◽  
O. Ivanova ◽  
K. Loganovsky ◽  
N. Korotkova ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radiation Dose ◽  
Nuclear Power ◽  
Radiation Doses ◽  
Total Radiation ◽  
Exclusion Zone ◽  
Permanent Residence ◽  
Total Radiation Dose ◽  
Effective Radiation

Background. Radiation accidents at the Chornobyl Nuclear Power Plant (USSR, 1986) and Fukushima-1 (Japan, 2011) have shown that global environmental contamination is an intervention in normal human life making negative effect on population health. These accidents highlighted a number of statutory and regulatory both with medical and social problems for individuals, who returned voluntarily for permanent residence in the Chornobyl Exclusion Zone i.e. a radiation-hazardous area (they are named the «self-settlers»). Objective: generalization of experience in the settlement of normative-legal, ecological-dosimetric and medicosocial life issues of population living in the Chornobyl NPP (ChNPP) Exclusion Zone («self-settlers»). Object and methods. The chosen problem is complex, necessitating the generalization of radiation-hygienic, medical-biological, socio-economic, demographic and sociological research results obtained by the national and foreign authors. A set of theoretical research and analysis of empirical data methods on the principles of interdisciplinary interaction was used; the systematic, legal, economic, medical-biological, demographic and retrospective-dosimetric approaches of research were applied. Results. It was shown that a part of population refused to evacuate or had returned for permanent residence to the radiation-hazardous lands after the ChNPP accident. In 1986–2009 the number of «self-settlers» ranged from 150 to 2,000 in different years. In 2021 – the 101 people. Those were mainly people of working age, mostly females, single people or widows/widowers. Рrevious medical and dosimetric studies have shown that long-term residence in the Exclusion Zone affects physical and mental health of «self-settlers» and causes atypical aging, including involvement of the central nervous system. According to calculations, the average effective total radiation dose accumulated by «self-settlers» for the first 3 years was 30 % of dose for the entire post-accident period, and the dose accumulated over 20 years was 54 % of the dose accumulated over 35 years. But the effective radiation doses accumulated in different periods after the accident differ significantly in residents of different Exclusion Zone settlements. This information needs further study in terms of the «radiation dose - health status» dependence. Conclusions. The effective radiation doses accumulated in different periods after the accident differ significantly in the residents of different Exclusion Zone settlements. Тhe average effective total radiation dose accumulated by «self-settlers» for the first 3 years was 30 % of the dose for the entire post-accident period, and the dose accumulated over 20 years was 54 % of the dose accumulated over 35 years. The Scientific Council meeting of NAMS approved the NRCRM Annual Report. Key words: Chornobyl Nuclear Power Plant, Exclusion Zone, «self-settlers», radiation doses, health.

scholarly journals Radiocaesium activity concentrations in parmelioid lichens within a 60 km radius of the Fukushima Dai-ichi Nuclear Power Plant

2015 ◽  
Vol 146 ◽  
pp. 125-133 ◽  
Author(s):  
Terumi Dohi ◽  
Yoshihito Ohmura ◽  
Hiroyuki Kashiwadani ◽  
Kenso Fujiwara ◽  
Yoshiaki Sakamoto ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Activity Concentrations

Problems of Radioactive Waste Management at Chornobyl Nuclear Power Plant (ChNPP)

2003 ◽  
Author(s):  
Borys Ya. Oskolkov ◽  
Yuri A. Neretin ◽  
Valeryi P. Saliy ◽  
Valeryi A. Seyda ◽  
Vyascheslav V. Fomin
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Radioactive Waste ◽  
Nuclear Power ◽  
Wide Spectrum ◽  
Liquid Radioactive Waste ◽  
Chemical Properties ◽  
Building Structures ◽  
Exclusion Zone ◽  
Management Problems

According to the assessments the overall amount of radioactive waste (RAW) to be reprocessed and buried at the Chornobyl NPP site amounts to 1,696,738 m3 (without regard for reactor metal structures, dismantling of building structures and plan constructions, and the Unit Shelter building). The overall activity of radioactive waste are evaluated at 1,640,504.64 ΤBq. The RAW management activities are implemented at the Chornoby1 NPP within the frame of several programs of different hierarchy including the State Comprehensive Program for RAW Management in Ukraine, Integrated Program of RAW Management at the Chornoby1 NPP Shutdown Stage and Transformation of the Unit Shelter into an Ecologically Safe System. At the present time a number of key RAW management facilities are being constructed within the frame of the international aid to Ukraine. They are the Liquid Radioactive Waste Plant and Solid Radioactive Waste Reprocessing Complex. As of now, the issues concerning RAW utilization at the Unit Shelter are resolved at a conceptual level. There has not practical decision in relation to a geologic facility. The complexity and scale of ChNPP RAW management problems will require significant efforts of both Ukraine and the whole world community to solve these issues. The task related to removal and final burial of accumulated and generating radioactive waste is one of the main aspects of decommissioning activities at any nuclear power plant. RAW management work is the most important and complicated work performed at the Chornoby1 NPP. The specific features of ChNPP RAW management are as follows: • Variety of RAW generation sources, their types, physical and chemical properties. • Large amount of radioactive wastes which already exist and those generated in the decommissioning process. • Presence of disorganized RAW characterized by wide spatial distribution within the Unit Shelter and at the plant site. • Need to apply a very wide spectrum of various RAW management techniques depending on their location and type. • Need in developing unique techniques to manage special types of RAW located at the site (fuel containing masses of the Unit Shelter). • Large amount and variety of facilities required for RAW final storage. • Absence of reliable and serviceable instrumental procedures and necessary equipment to define RAW properties for RAW separation and classification. • Ecological peculiarities of RAW management within the Chornoby1 zone. • Multiphase decontamination and restoration processes resulting in RAW formation. • Need in integrating RAW management problems at the ChNPP and within the Chornoby1 Exclusion Zone taken as whole. • Long time period required for implementing the whole program of RAW management at the ChNPP. • Large quantity of people involved in RAW management process (local and foreign participants, different organization operated by various departments).

Research on Operating Strategy of Total Loss of Essential Service Water System With RHR Not Connected in PWR Unit

2020 ◽  
Author(s):  
Shengtao Zhang ◽  
Ke Yi
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Heat Sink ◽  
Nuclear Power ◽  
Cooling System ◽  
Water System ◽  
Total Loss ◽  
Operating Strategy ◽  
Service Water ◽  
Essential Service

Abstract Essential Service Water System (WES) is part of the nuclear power plant cooling system which provides the final heat sink for nuclear power plants. Therefore, WES must operate stably, safely and reliably for a long time. The total loss of WES accident is a design extended condition and will result in the loss of the final heat sink of the unit. The consequences of the accident are severe. In order to deal with the accident quickly and effectively and ensure the safety and economics of the power plant in accident condition, it’s necessary to formulate corresponding treatment strategy to deal with the transient. This paper developed a strategy for dealing with the total loss of WES with Residual Heat Removal System (RHR) not connected condition in Generation III nuclear power plant. The structure of the WES system and the types of failures that may occur are analyzed, and thus the symptoms of the faults are obtained and the entry conditions for the operating strategy are determined. The effect of faults on unit equipment and safety functions and the impact on nuclear steam supply system (NSSS) control are analyzed in this paper. Combined with the unit design, the system and equipment for controlling and mitigating related safety functions are analyzed, and the mitigation method and the fallback strategy of the fault are determined. Thereby a complete operating strategy of total loss of WES with RHR not connected is obtained. In addition, this paper analyzes and evaluates the operating strategy by simulating thermal hydraulic calculation for the first time. The results show that without staff intervention Component Cooling System (WCC) temperature reached 55°C limits after running a few minutes. Based on the intervention of the operating strategy proposed in this paper, WCC temperature reached the 55°C limits when the unit was operated at about 4 hours and 55 minutes. The result shows that and the strategy can effectively alleviate the failure and provide sufficient intervention time for the operator to bring the unit to a safe state.

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