Analysis on Critical Factors of Marine Organism Impacts on Water Intake Safety at Nuclear Power Plants

2020 ◽  
Vol 6 (4) ◽  
Author(s):  
Xiaocheng Fu ◽  
Fenglei Du ◽  
Xiang Pu ◽  
Xuan Wang ◽  
Fengze Han

Abstract The safety of cooling water intake in nuclear power plants (NPPs) has gradually become an important factor affecting the safety of NPPs. Marine flora and fauna outbreaks are one of the main types affecting the safety of cooling water intake in NPPs, and the driving mechanism is more complicated and difficult to predict. This paper mainly analyzes the main types and typical cases of marine organisms that cause cooling water intake blockage in NPPs, and analyzes the key factors such as hydrodynamic conditions, timing of organism's outbreak, characteristics of species, and design of the screen systems. The results show that strong hydrodynamic conditions or strong tides caused by special meteorological conditions are important factors. Considering the time of organism's outbreak, spring and summer (May–August, may change slightly according to different latitude) is key period because of the reproduction and growth of most marine organisms, according to the growth law of marine organisms. In terms of biological characteristics, it is sensible to focus on those species with fast growth, strong reproductive capacity, short life cycle, weak swimming ability, and cluster distribution. As to the design of screen systems, the blockage mainly occurs in revolving filter screens. The grid spacing of normal mechanical grille is too large to block the small marine organisms. It is necessary to add trash interception nets according to the type and size of the marine species. Finally, a case is used to confirm the factors needed to pay more attention.

2021 ◽  
Vol 290 ◽  
pp. 03013
Author(s):  
Jianfei Zhang ◽  
Zhongpeng Wu ◽  
Chong An

In view of the frequent water intake blockage caused by marine biological invasion in many nuclear power plants, which affects the safety of cold source in nuclear power plants, a defense system in depth including marine biological identification, detection, early warning and hierarchical response is established through investigation and analysis of the causes of the event. Underwater acoustic high-resolution multi beam detection method is used to detect jellyfish, hairy shrimp and other marine organisms, The echo characteristics are obtained, the distribution density in sensitive sea area is analyzed, and the effective early warning judgment is given. Among them, detection and early warning is the front-end disposal measure, which can provide accurate and timely marine biological information for the subsequent hierarchical response. At the same time, it can replace the underwater inspection work of divers, reduce the risk of divers, reduce the risk of industrial safety, and improve the reliability of cold source.


2019 ◽  
pp. 54-60
Author(s):  
O. Fedonenko ◽  
O. Marenkov ◽  
O. Petrovsky

The article shows the research results on biological obstacles of the Zaporizhzhya NPP cooling pond, which may be harmful for the technological cycles of the plant or even cause emergency in the NPP. This problem is particular importance for cooling water reservoir of energy objects, since the increased temperature regime in such reservoirs creates favorable conditions for the mass development of certain types of hydrobionts, which hinder the operation of hydraulic structures. It was established that for the studied cooling water reservoir of Zaporizhzhya NPP all types of biological barriers that are found in technical reservoirs of nuclear power plants of Ukraine are characteristic. It has been established that all types of biological obstacles found in technical reservoirs of nuclear power plants of Ukraine are common for the researched reservoir. The most common are biological obstacles of bacterial, plant and animal origin. Plant biological obstacles are represented by the excessive growth of blue-green algae, which in the summer cause the "water blooming" of the cooling pond, and the filamentous algae that form thickets on the surfaces of concrete slabs and hydraulic structures. Animal biomarkers include the rapid spread of the mollusks of the Thiaridae family, which were accidentally inhabited into the water reservoir and caused massive fouling of the water development facilities of the NPP. One of the areas of biological control of biological barriers in a Zaporizhzhya NPP cooling water reservoir is ichthyomelioration – biomeliorative release the fish into the reservoir As fish occupy higher trophic levels in aquatic ecosystems, they accumulate organic matter from other trophic units and can inhibit the massive development of hydrobionts. The presented scientific results formed the basis of "Technological substantiation of the biological method of reducing the amount of phytoplankton and mollusks in the hydraulic engineering system of the ZNPP and conducting biomeliorative works using biomeliorative fish for the period2018-2022", the observance of which allows partial resolution of the problems of biological barriers caused by the mass development of certain species.


1974 ◽  
Vol 9 (1) ◽  
pp. 188-195
Author(s):  
G. Bethlendy

Abstract Even with the latest technology, more than 60% of the heat produced by any thermal engine - whether the fuel is coal, oil, gas or uranium - must be taken back into the environment by cooling water or exhaust gas. For economical reasons, the usual means of disposing of the “waste” heat from a thermal-power plant is to pump river, lake or sea water through the parts of the plant concerned. Nuclear power plants use their heat as efficiently as older thermal plants, 30–33%. Modern thermal plants, however work with as high as 40% efficiency, and release about 10–13% of their total fuel-heat into the air through the stack. As a result of the combination of all these factors, nuclear power plants release about 68–70% of total input heat into the cooling water. In practice this means that the plant must be able to draw upon a source of cooling water which is large enough, which flows quickly or is cold enough not to be seriously effected by the return of warmed-up water from the power station. Where this is not possible, it may be necessary to build relatively expensive cooling ponds and/or towers so that the heat is also released to the air rather than only to a local body of water. The thermal effects could be detrimental or beneficial depending on the utilization of the water body. At the present time the utilities are aware of these problems and very extensive aquatic studies are being made before and after the construction of the plants. Some beneficial uses of waste heat are being sought via research and demonstration projects (e.g. in agriculture, aquaculture, district heating, etc.).


2021 ◽  
Vol 7 (4) ◽  
pp. 26-33
Author(s):  
Quang Huy Pham ◽  
Sang Yong Lee ◽  
Seung Jong Oh

The accident in Fukushima Daiichi nuclear power plants shows the important of developing coping strategies for extended station blackout (SBO) scenarios of the nuclear power plants (NPPs). Many NPPs in United State of America are applying FLEX approach as main coping strategies for extended station blackout (SBO) scenarios. In FLEX strategies, outside water injection to reactor cooling system (RCS) and steam generators (SGs) is considered as an effective method to remove residual heat and maintain the inventory of the systems during the accident. This study presents a pretest calculation using MARS code for the Advanced Thermal-hydraulic Test Loop for Accident Simulation (ATLAS) SBO experiment with RCP seal leakage scenario. In the calculation, the turbinedriven auxiliary feed water pumps (TDAFPs) are firstly used after SBO initiation. Then, the outside cooling water injection method is used for long term cooling. In order to minimize operator actions and satisfy requirements of APR1400 emergency operation procedure (EOP), the SGs Atmospheric Dump Valve (ADV) opening ratio, auxiliary feed water (AFW) and outside cooling water injection flow rates were investigated to have suitable values. The analysis results would be useful for performing the experiment to verify the APR 1400 extended SBO optimum mitigation strategy using outside cooling water injection.


2014 ◽  
Author(s):  
M. Bazaleev ◽  
B. Banduryan ◽  
V. Klepikov ◽  
S. Donets ◽  
V. Lytvynenko ◽  
...  

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