Comparison of Plant Life Management Approaches for Long Term Operations

Author(s):  
Frank Nuzzo ◽  
Ki-Sig Kang

Many Member States of the International Atomic Energy Agency (IAEA) have given high priority to long term operation of nuclear power plants beyond the timeframe originally anticipated (e.g. 30 or 40 years). Out of a total of 445 (369 GWe) operating nuclear power plants, 349 units (297 GWe) have been in operation for more than 20 years (as of November 2011) and many are engaged in investigations and studies aimed at prolonging the plant service life. The need for engineering support to operation, maintenance, safety review and life management for long term operation as well as education and training on LTO issues is increasingly evident. Plant life management (PLiM) techniques that can be defined as the integration of ageing and economic planning, have been used in operating nuclear power plants to maintain a high level of safety, optimize performance and justify long term operation (LTO) beyond the plant design life. In addition, as a follow up to the Fukushima accident, operators have become even more attentive to beyond design basis measures in the preparation of their plants for operation beyond their design life. In many countries, the safety performance of NPPs is periodically assessed and characterized via the periodic safety review (PSR) process. Regulatory review and acceptance of PSRs constitutes for these countries the licensing requirement for continued operation of the plant to the following PSR cycle (usually 10 years). In the USA and in other countries operating US designed plants, instead of a PSR process, a license renewal application (LRA) process is followed, which requires certain pre-requisites such as ageing management programmes, particularly for passive irreplaceable systems structures and components (SSCs). Active components are normally addressed via the maintenance rule (MR) requirements and other established regulatory processes. A third group of Member States have adopted a combined approach that incorporates elements of both the PSR process and selected LRA specific requirements, such as time limited ageing analysis. Taking into account this variety of approaches, the IAEA initiated work to collect and share information among Member States on good practices in plant life management for long term operation in nuclear power plants, by comparing the various approaches to the PSR reference and by drawing lessons learned from relevant applications and experiences.

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Mauro Cappelli ◽  
Francesco Cordella ◽  
Francesco Bertoncini ◽  
Marco Raugi

Guided wave (GW) testing is regularly used for finding defect locations through long-range screening using low-frequency waves (from 5 to 250 kHz). By using magnetostrictive sensors, some issues, which usually limit the application to nuclear power plants (NPPs), can be fixed. The authors have already shown the basic theoretical background and simulation results concerning a real steel pipe, used for steam discharge, with a complex structure. On the basis of such theoretical framework, a new campaign has been designed and developed on the same pipe, and the obtained experimental results are now here presented as a useful benchmark for the application of GWs as nondestructive techniques. Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPPs components.


Author(s):  
Oliver Martin ◽  
Antonio Ballesteros ◽  
Christiane Bruynooghe ◽  
Michel Bie`th

The energy supply of the future in the EU will be a mix of renewable, fossil and nuclear. There are 145 nuclear power reactors in operation in 15 out of the 27 EU countries, with installed power ∼132 GWe. The age distribution of current nuclear power plants in EU is such that in 2010 most of them will have passed 20-years and approximately 25% of them 30 years of age. The decrease of energy supply from nuclear generated electricity can not always be compensated in a reliable and economical way within a short time span. For this situation utilities may be keen to upgrade the reactor output and /or to ask their regulatory bodies for longer term operation. Under the research financed in the Euratom part of the Research Directorate (RTD) of the European Commission several projects explicitly address the safe long term operation of nuclear power plants (NULIFE, LONGLIFE) and the topics proposed in the 2010 call explicitly address issues concerning component ageing, in particular non metallic components, i.e. instrumentation and cables (I&C) and concrete ageing. This paper presents an overview of the plans for long term operation (LTO) of nuclear power plants in the EU. Special emphasis is given on research activities on component ageing management and long term operation issues related to safety.


Author(s):  
Paolo Contri ◽  
Povilas Vaisnys ◽  
Bernhard Elsing

Due to current social and economical framework, in last years many nuclear power plant owners started a program for the Long Term Operation (LTO)/PLIM (Plant Life Management) of their older nuclear facilities. A PLIM framework requires both a detailed review of the features of the main safety programs (Maintenance, ISI, Surveillance) and a complete integration of these safety programs into the general management system of the plant. Therefore PLiM should address safety as well economics, knowledge management as well as decision making, and provide an overall framework to keep the whole plant in a safe and economically sustainable condition. Moreover, new external factors, such as: large use of subcontractors, need for efficient management of spare parts, request for heavy plant refurbishment programs demand for updated techniques in the overall management of the plant. Therefore new organisational models have to be developed to appropriately support the PLIM framework. In recent years a network of European Research Organisations (SENUF) carried out many R&D tasks aiming at capturing the aspects of the maintenance programs where research is mostly needed and at developing suitable optimised maintenance models. Using the outcome of these initiatives, this paper aims at identifying the technical attributes of the PLIM program more directly affecting the decision for a long-term safe operation of a nuclear facility, and the issues related to its optimal implementation. A comparison of some of the available models is presented and an analysis of the potential impact on safety and non-safety programs is provided in order to support the development of optimised life management models.


Author(s):  
Garry G. Young ◽  
Mark A. Rinckel

License renewal of operating nuclear power plants in the United States has become one of the most successful nuclear industry activities in the past few years. It is anticipated that over 90% of the 103 operating nuclear power plants in the United States will pursue license renewal and seek an additional 20 years of operation. Some plants may pursue operation to 80 years or longer since the license renewal rule does not limit the operating life of a nuclear power plant. The requirements for renewing the operating license of a nuclear reactor in the United States are contained in Nuclear Regulatory Commission (NRC) Regulation 10 CFR Part 54, which addresses general, technical, technical specification, and environmental requirements. The most labor intensive element of the requirements are the technical requirements, which include addressing an integrated plant assessment (IPA) and time limited aging analyses (TLAA). The cost of performing the needed reviews and obtaining a renewed license ranges between $10M to $15M. The license renewal rule focuses on aging of passive long-lived components and aging management programs that manage those structures and components. The aging management programs credited to manage aging include both existing programs (e.g., ASME Section XI) and a few new programs (e.g., Reactor Vessel Internals Aging Management Program). Commitments to aging management programs for license renewal may be implemented and tracked through a comprehensive plant life management (PLIM) program. PLIM is the process to integrated equipment aging management with other plant activities to maximize plant value. PLIM can save the operating plant a significant amount of money by effectively planning and implementing component refurbishment and replacement. The ultimate decision to seek license renewal and continue operation is based on PLIM, which considers aging, safety, and economics.


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