Service life extension of power-generating units in nuclear power plants

Atomic Energy ◽  
2000 ◽  
Vol 88 (1) ◽  
pp. 10-15
Author(s):  
O. M. Kovalevich
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Life Extension ◽  
Service Life Extension

IAEA Activities on Concrete Ageing in Containment and Other Structures in Nuclear Power Plants

2013 ◽  
Author(s):  
Ki-Sig Kang ◽  
John H. Moore
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Concrete Structures ◽  
Operating Experience ◽  
Life Extension ◽  
Spent Fuel ◽  
Design Life ◽  
Ageing Management

Significant industry developments over the past decade have placed concrete ageing at the forefront of life extension decisions related to nuclear power plants. Recent issues encountered include alkali–silica reactivity in concrete, delamination events, larger than anticipated loss of pre-stressing force, spent fuel pool leakage, corrosion of steel reinforcement in water intakes, and others. Concrete structures at nuclear power plants are being asked to perform for longer periods than originally design life. Utilities around the world are investigating plant service life extensions (with 60 years or more total being a quoted target), and for some projects delayed construction schedules, and/or decommissioning strategies that involve the use of containment as a “safe store” for periods of up to 100 years, mean that containment buildings and other concrete structures often have to perform their functions for a time period significantly greater than their initial design life. Newer plants are designed with design lives of 60 years or more. Concrete is a durable material and its performance as part of the containment function in NPPs has been good. However, experience shows that ageing degradation of concrete structures, often caused or accelerated by factors such as faulty design, use of unsuitable or poor quality materials, improper construction, exposure to aggressive environments, excessive structural loads, and accident conditions, can impair its safety functions and increase risks to public health and safety. Effective ageing management of concrete containment buildings and other concrete structures is therefore required to ensure their fitness-for-service throughout the plant service life and during decommissioning. The paper presented will present current International Atomic Energy Agency activities in the area of concrete structures and ageing management, and point to where guidelines and best practises related to concrete structure ageing management, relevant operating experience, and applicable codes and standards may be located.

Life Extension of Nuclear Power Plants: World Situation and the USA Case

2010 ◽  
pp. 50-56 ◽  
Author(s):  
Pablo T. León ◽  
Loreto Cuesta ◽  
Eduardo Serra ◽  
Luis Yagüe
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Life Extension ◽  
The Usa

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.

Development of Russian Regulatory Basis for License Renewal/Life Extension of Nuclear Power Plants

2002 ◽  
Author(s):  
Jaroslav Pachner ◽  
Inna V. Kaliberda
Keyword(s):  
Power Plant ◽  
Service Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Life Extension ◽  
Safety Standard ◽  
Regulatory Strategy ◽  
Regulatory Guidelines ◽  
License Renewal ◽  
Regulatory Organization

By 2010, fifteen Russian nuclear power plant (NPP) units will reach the end of their scheduled service life of 30 years. An extension of NPP operation beyond the scheduled service life, which is provided for by the Russian safety standard OPB-88/97, requires a renewal of the plant operating license by the regulatory organization Gosatomnadzor (GAN). This paper presents an overview of an IAEA project aimed at assisting GAN in the development of a set of regulatory guidelines for NPP license renewal/life extension. The overview includes a description of the Russian regulatory strategy for life extension of NPPs and IAEA activities to facilitate drafting and application of the regulatory guidelines using international experience.

Fatigue Monitoring: Case Studies in Nuclear Power Plant

2018 ◽  
Author(s):  
G. Bourguigne ◽  
F. Schroeter
Keyword(s):  
Power Plant ◽  
Thermal Stratification ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Life Extension ◽  
Monitoring Systems ◽  
Fatigue Monitoring ◽  
Cycle Count ◽  
Critical Components

During design of Class I components in Nuclear Power Plants, cumulative usage factors (CUF) are conservatively calculated to estimate fatigue damage, and results must be below the limits of the applicable codes. Nevertheless, when these results are used to evaluate the possibility of using these components for an extended life, the results are frequently above code limits. Many Nuclear Power Plants have installed commercial fatigue monitoring systems at critical components in order to assess transient severity and cycle count for life extension fatigue calculations among other reasons. Since the commissioning of the system, unexpected operation modes and thermal stratification was discovered and evaluations needed to be done. Findings, interpretations and solving are presented in this paper.

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