Open Service Cooling Water Supply Systems of Nuclear Power Plants as Environmental Regulators of Natural-Technical Systems

The paper presents review of the requirements from the new regulation NP 306.2.205-2016 “Requirements for Power Supply Systems Important to Safety of Nuclear Power Plants” and recommendations of IAEA and WENRA for the construction of electrical systems important to safety of nuclear power plants. The research is focused on main differences of NP 306.2.205-2016 from standards that applied to NPP emergency power supply systems (PNAE G-9-026-90, PNAE G-9-027- 91) and which were cancelled in 2016.

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The Problem of Biological Obstacles in the Operation of Nuclear Power Plants (Illustrated by the Operation of Zaporizhzhya NPP Techno-Ecosystem)

Nuclear and Radiation Safety ◽

10.32918/nrs.2019.2(82).10 ◽

2019 ◽

pp. 54-60

Author(s):

O. Fedonenko ◽

O. Marenkov ◽

O. Petrovsky

Keyword(s):

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Cooling Water ◽

Water Reservoir ◽

Trophic Levels ◽

Hydraulic Structures ◽

Cooling Pond ◽

Biological Barriers ◽

Mass Development

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.

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

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4048112 ◽

2020 ◽

Vol 6 (4) ◽

Author(s):

Xiaocheng Fu ◽

Fenglei Du ◽

Xiang Pu ◽

Xuan Wang ◽

Fengze Han

Keyword(s):

Water Intake ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Marine Organism ◽

Cooling Water ◽

Marine Organisms ◽

Reproductive Capacity ◽

Driving Mechanism ◽

Hydrodynamic Conditions

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.

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