Investigation of the Influence of Operational Loading Regimes on the Service Life of Nuclear Power Plants

2020 ◽  
pp. 319-330
Author(s):  
Nikolay A. Makhutov ◽  
Mikhail M. Gadenin ◽  
Sergey V. Maslov ◽  
Dmitry O. Reznikov ◽  
Sergey N. Pichkov ◽  
...  
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants

Research of Technology for Repair of Heat Exchangers of Nuclear Power Plants by Laser Welding

2021 ◽  
Vol 313 ◽  
pp. 94-105
Author(s):  
A. Bernatskyi ◽  
V. Sydorets ◽  
O.M. Berdnikova ◽  
I. Krivtsun ◽  
O. Kushnarova
Keyword(s):  
Service Life ◽  
Laser Welding ◽  
Welded Joints ◽  
Heat Exchangers ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Mechanical Test ◽  
Austenitic Steels ◽  
Depth Of Penetration

Extending the lifetime of energy facilities is extremely important today. This is especially true of nuclear power plants, the closure (or modernization) of which poses enormous financial and environmental problems. High-quality repair of reactors can significantly extend their service life. One of the critical parts is heat exchangers, the tubes of which quite often fail. Sealing, as a type of repair of heat exchanger tubes by the plugs, is promising provided that the joint quality is high. Practical experience in the use of welding to solve this problem has shown the need to search technological solutions associated with increasing the depth of penetration and reducing the area of thermal effect. The aim of the work was to develop a highly efficient technology for repair and extension of service life of heat exchangers of nuclear power plants based on the results of studying the technological features of laser welding of joints of dissimilar austenitic steels AISI 321 and AISI 316Ti in the vertical spatial position. Based on the results of the analysis of mechanical test data, visual and radiographic control, impermeability tests and metallographic studies of welded joints, the appropriate modes of laser welding of plugs have been determined. The principal causes of defects during laser welding of annular welded joints of dissimilar stainless steels are determined and techniques for their elimination and prevention of their formation are proposed. Based on the results of the research, technological recommendations for laser welding of plugs in the heat exchange tube of the collector are formulated, which significantly improves the technology of repair of steam generators of nuclear power plants and extends the service life of reactors.

Aging of materials of the equipment of nuclear power plants after designed service life

2006 ◽  
Vol 42 (2) ◽  
pp. 155-169 ◽  
Author(s):  
I. V. Gorynin ◽  
B. T. Timofeev
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants

scholarly journals Main Approaches to Cable Aging Management at Nuclear Power Plants in Ukraine

2019 ◽  
pp. 54-62
Author(s):  
T. Bilan ◽  
I. Rezvik ◽  
O. Sakhno ◽  
O. But ◽  
S. Bogdanov
Keyword(s):  
Service Life ◽  
Temperature Dependence ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Insulation Material ◽  
Term Operation

The mechanisms of cable ageing at nuclear power plants (NPPs) mainly depending on the insulation material, as well as the damaging factors affecting cables that are determined by the operating conditions are considered in the paper. The main and additional mechanisms of aging resulting from the effects of damaging factors are provided. The paper presents the main methods of cable aging management: determining the actual service life and testing using field methods and other means. The basic principles for the arrangement of cable aging management at Ukrainian NPPs, as well as the methods used to investigate the technical condition of cables, are presented. A list of mandatory lists has been defined when performing activities on cable aging management. A methodology is described for lifetime extension of cables, and conditions for extending the service life of cables that are in service are provided. A number of methods of testing cables for aging management are considered: visual inspection of insulation and measurement of crack size, discoloration, etc.; insulation hardness test; insulation chemical analysis; electrical insulation tests; tensile strength measurement; measurement of elongation at break; measurements of dielectric loss at low frequency or sweep frequency; testing by dynamic reflectometry method; AC and DC current impedance measurements. The paper presents results of separate laboratory studies for selected 1 kV representative power cables with PVC insulation of SUNPP-1, ZNPP-1 and KhNPP-2 conducted within Ukrainian NPP long-term operation, which included a stage of laboratory examination and examination of cable samples in operating conditions. The following results were obtained: dependence of VVGng 4x6 cable lifetime on operating temperature; dependence of AVVG cable lifetime on operating temperature; dependence of AVVG (a) cable lifetime on operating temperature. There are possibilities and conditions under which the use of cables within long-term operation is permissible.

Reliability and service life of VGKK series sealed lead-throughs for nuclear power plants

Atomic Energy ◽  
2008 ◽  
Vol 104 (3) ◽  
pp. 212-217
Author(s):  
N. S. Kostyukov ◽  
V. A. Demchuk ◽  
V. A. Okhotnikov ◽  
M. I. Muminov ◽  
Kh. B. Nurmatov
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants

scholarly journals Technical diagnostics of electrically operated valves at npp

2020 ◽  
Vol 216 ◽  
pp. 01022
Author(s):  
A.R Akhmetshin ◽  
V.N Golomidov ◽  
R.R Vildanov
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Technical Diagnostics ◽  
Operation Efficiency

The article discusses the possibilities of technical diagnostics of electrically operated valves at nuclear power plants in order to increase their reliability and service life, as well as to achieve maximum operation efficiency of systems in nuclear power plants.

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