E-Journal of Advanced Maintenance Vol.1 (2009) 30-43
Japan Society of Maintenology

Research priorities at the European Commission in relation to
Maintenance Optimization and Nuclear Power Plant LifeManagement
Paolo CONTRI1,*
1

European Commission, Joint Research Center's Institute for Energy, Westerduinweg 2, 1755WG
Petten, The Netherlands(Received; November 29th, 2008)

Abstract. Analysis of experience in many countries operating nuclear power plants (NPPs) suggests that, while
differences in long term operation (LTO) programs are mainly related to the various national regulatory
processes, the main features and basic technical requirements are similar. The implementation of these howeverneeds reshaping in an integrated plant life management (PLIM) framework, bearing in mind the specific safety
implications of LTO. R&D is essential to support this process, not only for long term extrapolation of thecomponent integrity and behavior, but also for a proper maintenance system and for an adequate management
structure ensuring effective management strategies at plant level, able to address organizational issues, sparepart management, staff ageing, component obsolescence, etc. This is recognized by the European Commission,
which supports R&D in targeted areas in the framework of the EURATOM program, both by “direct actions”
i.e. projects managed and executed by its Directorate General Joint Research Centers (JRC) and by indirect
actions i.e. funding of selected projects, managed by the Directorate General Research (RTD). This paper
outlines the JRC’s priorities in the current 7th Framework Programme in relation to R&D tasks for maintenanceand ISI to support the highest safety level at member’s NPPs and appropriate decision-making tools for the
optimization of these programs. A newly developed UE model for PLIM, also integrating maintenanceoptimization issues, is presented for further discussion.

KEYWORDS: nuclear plants, maintenance, plant life management, research programs, European Union

1. Introduction
The current social and economic framework for the energy production is characterized by thefollowing trends:
1) The open electricity market, which is going to be a reality in most of the European Countries
in few years. Such economical and financial framework demands for significant reduction of
the generation costs, very strict investment planning, outsourcing, controlled reliability of theequipment and components (incl. obsolescence) and therefore for reliable indicators of theeffectiveness of the maintenance programmes
2) The generic trend towards the extension of the operating life of the existing plants. Such life
extension requires a detailed review of the original design assumptions, also reflected intocurrent maintenance practice, and the continuous monitoring of the component reliability(performance goals) in order to support a suitable trend of the safety evaluation beyond thedesign life.
As a consequence, in last years many electric utilities and nuclear power plants adopted policies
for improved coordination of both safety and non-safety programs, called plant life management(PLIM). Its implementation has followed many different approaches, being intrinsically dependent*

Correpsonding Author, E-mail: paolo.contri@ec.europa.eu

ISSN – 1883 – 9894/09 © 2009 – JSM and the authors. All rights reserved.

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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Managementon the national regulatory framework and technical traditions. The LTO process poses further
challenges, particularly in view of the nuclear safety implications as well as the economic strategic
and political ones. Therefore in recent years the need for tailoring available safety assessment tools tosuch needs has become very urgent. However, such adaptation often proved very complex due to thelong time perspective of the PLIM (typically 30-40 years), as compared to the typical timeframework where the available methods are currently employed (~10 years of the standard
periodicity of the Periodic Safety Review process).
In Countries with some experience, the PLIM program proved very convenient, especially whencoupled with Maintenance, Surveillance an Inspection (MS&I) optimization: average savings arereported in the range of 20-30% of total (maintenance) costs.
Moreover, in terms of safety, the control of equipment reliability, significantly improved with PLIM
models for example through Ageing Management Program (AMP) and Reliability Centred
Maintenance (RCM), made a long term asset management of the overall plant possible and theoverall safety indicators significantly improved in many cases.
This is why R&D tasks are needed in this phase, not only in the long term extrapolation of thecomponent integrity and behavior, but a also in new management strategies at the plant (PLIM), able
to address organizational issues, spare part management, staff ageing, component obsolescence, etc,
which are typical components of the PLIM (see for example [1]).
The Framework Programme 7 of the EU (FP7 [2] - Council decision 18/6/2006) in the area
dedicated to the reactor systems calls for a research effort “to underpin the continued safe operationof all relevant types of existing reactor systems (including fuel cycle facilities), taking into accountnew challenges such as life-time extension and development of new advanced safety assessment
methodologies (both the technical and human element)”.
Consequently, the JRC Multi Annual Work Program (MAWP), in the Nuclear Safety “agenda”
under the Euratom Program, developed two main tasks addressing the safety of nuclear installations
and the nuclear fuel safety, respectively. The former is addressed in the following, being relevant tothis context.
This paper provides a short summary of selected results obtained at the JRC under the 7th
Framework programme (2007-2010) and summarizes the perceived scientific/technologicalchallenges for FP7 on which JRC proposes to focus, based upon its competencies and skills, havingin mind both the European and world-wide context and its potential evolution.
2. The PLIM problem – Definitions and selected EU experience
2.1.

Setting the problem

The Plant Life Management (PLIM) problem was raised some years ago when it was clear thattechnological, safety, regulatory, human and economical issues had to be addressed at once in theoverall management of the plant assets [1,2].
It is a fact that new global approaches have been triggered in recent years by a combination offactors such as:• The generic trend towards plant life extension beyond the original design life, in order toexploit the plant design at the maximum level• The market economy, which is pushing for a more stringent management of the economic
assets• The detection of significant ageing phenomena which were challenging the original design
assumptions• The need for preservation of the human knowledge in time, particularly in Countries withgrowing opposition to nuclear expansion• The more stringent regulatory requirements in terms of safety assessment and monitoring
However, the PLIM models developed in recent years differ one from another because of thenational frameworks and therefore a generalization sometimes appear difficult.
Interesting attempts were carried out by the International Atomic Energy Agency with sometechnical documents and papers [2], to identify common drivers among the different national
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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

programs, but the discipline was never indeed regulated by binding documents to its Member States,by presenting commonly accepted principles, recognized by all the interested parties. Nevertheless, alarge number of IAEA documents are available on basic safety concepts that could be relevant to life
management programs [6-16].
In particular, a generic misunderstanding still survives in the engineering community among
objectives and content of the different programs put in place in the different Countries whichdeveloped experience in the PLIM field. Programs such as License Renewal (LR), Long Term
Operation (LTO), Plant Life Extension (PLEX), Periodic Safety Review (PSR), Ageing Management
Program (AMP), etc. proved to share many technical tasks, but also to meet different objectives andto follow different regulatory frameworks.
The JRC-IE spent some research efforts in last years in the clarification of the many issues
addressed by the European Countries' programs and developed some unified models, which received
very high consensus in many engineering communities and particularly in the research network ofEuropean Countries interested to this discipline, SENUF [5]. A number of scientific papers were also
published in order to foster the feedback from the engineering community [17-22].
As outcome of this effort, a list of generic considerations was developed as support to thedevelopment of a more unified approach to the common issue of managing the plant assets in time,
meeting the highest safety standards:
1. The PLIM program appears the type of program most suitable to address long-lasting safety
and economical issues and to present the most comprehensive approach to the plant asset
management
2. The PLIM program is neither necessarily related to plant life extension, nor to license
extension of any plant. It is a logical framework on which strategic thinking may find theappropriate answers in relation to safety, economy and human asset management.
3. Related programs such as LR, AMP, PSR, each with its own objective, may find in the PLIM
framework the answers and the background information that they need to meet their specificobjectives; however, they definitely represent separate programs, different from PLIM itself.
4. The PLIM program is crucially based upon a strong integration of many existing programs at
the plants, such as asset management, life extension, ageing management, configuration
control, predictive maintenance, etc. that share common assumptions and contribute to thesame overall objectives.
5. Some special features are required to standard programs and also some specific programs areneeded to be in place at NPPs in order to feed a PLIM program adequately. Thesefeatures/programs creates the pre-conditions for a PLIM program to be successfully applied,such as: the maintenance program should be mostly reliability based, the ISI program should
be possibly risk informed, a fuel management program should be in place, an outage
optimization program should make available all data in relation to the economic implicationsof the outage duration, a knowledge management program should be in place, public
acceptance analysis should be available, etc.
6. In order to manage the very complex structure of a PLIM program, specialized software tools
and databases are highly recommendable, also for the management of the daily work, due tothe huge amount of data to be processed and stored.
One example of approach to PLIM is shown in Fig.1, taken from the Finnish practice [5].
In this example, the PLIM program aims at demonstrating that during the design and possibly theextended plant operational life [3]:1. The safety and ageing analysis remain valid and could be projected to the end of intended
operational lifetime;
2. The effects of ageing on the intended safety function(s) are adequately managed all along theenvisaged lifetime;
3. There is a mechanism to deal with unexpected ageing mechanisms that can surface.
4. There is a pro-active process for decision making, also involving non-safety equipments
significant to plant availability
5. There is a program to manage human resources and knowledge
6. Plant economic assets are properly managed
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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

Fig. 1. Examples of approach to component life management [5].

In this framework some programs play the most crucial role, namely:• The ageing management program (AMP)• The maintenance, surveillance and inspection (MS&I) program• The knowledge management program (KM)
• The asset management program• Major plant upgrading programs (if in place, such as power uprating, modernization, etc.)
In particular, the AMP is a transversal program [3] cross-cutting maintenance, surveillance, andin service inspection programs and other operation related programs. It addresses ageing mechanisms
prevention, control and consequence mitigation. The operating experience shows that active andshort-lived SSC are in general addressed by existing maintenance programs. Conversely, theperformance and safety margins of the passive long-lived SSC are assumed to be guaranteed bydesign. However, the analysis of the operating experience showed that unforeseen ageing phenomena
may occur either because of shortcomings in design, manufacturing or by operating errors, calling fora refined, self-improving program.
The maintenance program for a nuclear power plant covers all preventive and remedial measuresthat are necessary to detect and mitigate degradation of a functioning SSC or to restore to an
acceptable level the performance of design functions of a failed SSC [15]. In this sense, theintegration with surveillance and in-service inspection is crucial, as the most advanced types ofmaintenance do integrate the three programs which have a common objective: to ensure that the plantis operated in accordance with the design assumptions and within the operational limit andconditions. Therefore in the following, MS&I will address all the three programs in an integratedform.
It is clear that the MS&I program is a crucial part of PLIM, being by far the main contributor toboth operating costs (after operation) and operation planning.
However, in order to support a PLIM framework, MS&I should have a specific list of attributes,
making both safety assessment and cost optimization possible.
In conclusion, the implementation of an AMP and a predictive MS&I (maintenance, surveillance andinspection) program is definitely a condition for the operation within the limits of design or licensed
lifetime and is a condition for a PLIM as well.
KM and asset management are traditionally isolated programs from MS&I and AMP. PLIM
recognizes the need for their integration and sets an overall optimization framework.

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P.Contri/Research priorities at the European Commission
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and Nuclear Power Plant Life Management

2.2.

Countries' generic experience with PLIM

Thanks to the large survey on Countries' practice carried out at the JRC [5], also through theorganization of many international events, it was possible to summarize the most relevant aspects ofsome Countries' practice in the field of PLIM, with special emphasis to the relationship with otherprograms running at the EU Countries.
• The USA, Canada, Spain and some other Countries accumulated a valuable experience inrecent years in PLIM issues and related programs. The interest of the international communityof plant operators on reliability based approaches to PLIM and maintenance optimization inparticular is definitely growing. The US approach is codified in the INPO AP-913 [23],closely followed by some Europeans.
• Other European Countries are more in favor of integrated approaches to Plant Life, such as
Finland, with a more explicit control of the component degradation and a clear day-to-day
basis for the decision makers on replacement, maintenance and operation.
• In many European Countries, PLIM is accompanied with a PSR program. The combination is
not surprising, as PLIM is typically a utility driven program, while PSR is driven by the
Safety Authority. Many technical tasks (those safety related) are similar, but objectives, timeframe and regulatory implications are definitely different.
• Some pre-conditions for PLIM in many countries include maintenance optimization, RI-ISI,
fuel management, outage optimization, knowledge management, public acceptance, seismic
upgrading, etc. making sometimes the program very complex. In all cases they are assisted bycomplex software tools and databases, also for the management of the daily work.
• The relationship among PLIM and the other programs running at the NPPs is now quite clear
in the EU Countries: well known programs such as component integrity, ageing management(AMP), life extension (PLEX), periodic Safety Review (PSR) and Plant Life Management(PLIM) are in fact well connected, but definitely not interchangeable. Despite of the different
names, mostly derived from the national regulatory and engineering frameworks, there is aclear hierarchy among them. In particular, component integrity is a basic science dealing withthe failure modes of the different components, their detection and their control. The AMP is
an operational program in place at any NPP, which integrates maintenance, ISI andorganizational issues aiming at controlling the component degradation. PLiM addresses safety
as well as economics, knowledge management as well as decision making, and provides anoverall framework to keep the whole plant in a safe and economically sustainable condition.
2.3.

PLIM at the design stage for the new reactors in the EU: AP1000 and EPR

The comparison of the approach to PLIM among other technology areas suggests someinteresting considerations. For example, in the aerospace industry the maintenance program(considered one of the most crucial component in PLIM) is optimized at the design phase, due to thelarge number of identical aircrafts; in the nuclear practice, time is needed to accumulate statistics andto develop confidence in the optimization procedures.
However, it is common judgment that PLIM should be applied since the design phase of the
NPPs, possibly based on the lesson learnt from the operating fleets. In this sense, practice could be
assimilated to that in other industrial technologies, as mentioned above.
Up to today, the development of standards and design rules for the new generation reactors is
lagging behind. This delay also makes the certification of the new reactors quite difficult. At thesame time, also the safety assessment methods and the QA rules for construction and operation need
to be revised. The role of both licensee and regulators is still to be defined in many countries.
This generic statement is applicable also to the PLIM relevant aspects which do deserve an
early understanding at the design phase. In particular, ageing considerations should be addressedsince the design stage, for example providing inspectability, replaceability, and access to the mostsensitive components and a solid basis for the control of their degradation.
Ageing should also be addressed since the beginning of operation in order to make available a
broad range of data for trending and optimization.
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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

In particular, the following PLIM/ageing relevant issues should be addressed in the pre-designor pre-licensing phase of new reactors:• Choice of materials• Major drawings• Operating conditions• Collection of relevant data
• Monitoring, surveillance• ISI : inspectability / access• Radiation protection of workers
For example, in the Areva/EPR, the following design actions are taken in order to improve the
PLIM performance [24]:• Accessibility of the reactor building during normal operation to perform maintenance tasks
and inspections, but also to start refueling seven days before reactor shutdown and tocontinue demobilization three days after reactor restart• Improved main coolant loop cool down, depressurization and vessel head opening after
shutdown bringing the standard outage time to 16 days.
• Very low radiation level to workers• Some modifications in SG or Pressurizer or RVI• Improvements of nozzles and tees for thermal fatigue reduction• In general FU factors have to be less than 0.5 for limited ISI in Operation
In the Westinghouse AP1000 [25] the following design actions intend to address the PLIM issues:• Large use of passive features, also to reduce MS&I tasks• Variable speed in the reactor coolant pump, to shorten startup and shutdown• Special design of the digital I&C which reduces the I&C surveillance testing• Large use of component standardization to reduce parts inventory and training• Built-in testing capabilities is provided for many critical components• Easy access for MS&I tasks and lifting devices• Few nuclear grade equipment• Very low radiation level to workers
3.

The maintenance program in the Long Term Operation perspective: why PLIM needs an
optimized maintenance program?

In 2003 the JRC-IE carried out a preliminary investigation of the priorities in the European
Countries in relation to the PLIM programs. The conclusion was that there is a generic convincementin the nuclear community that the maintenance program should have specific attributes in order tosupport a long term operation (LTO/PLEX) program for the plant. In this sense, the International
Standards (e.g. the IAEA), but also the national experience of USA, Spain, Hungary, etc. proved a
confirmation of this statement. More specifically, the maintenance programs based on standard
preventive maintenance (time based), not oriented to the monitoring of its effectiveness and to theprediction of the damage, are not considered suitable to support the LTO/PLEX programs. Crucial
attributes for maintenance programs in order to support LTO/PLEX are considered: the verificationof the performance goals, the root cause analysis of failures, the feedback from maintenance to the
ISI program, and the feedback on the OLC (operational limits and conditions).
All Countries implementing an LTO program applied extensive modifications to theirrequirements on maintenance at first step, setting up mechanisms to monitor the effectiveness of themaintenance activities. In particular, the following features are believed to be indispensable for amaintenance program in a PLIM framework:
1) Monitor the performance of the SSCs (structures, systems and components) which may
have impact on safety during all operational statuses of the plants;
2) Assess and manage the risk that may result from the proposed maintenance activities interms of planning, prioritization, and scheduling.
In order to implement these requirements, some issues have to be addressed, namely:
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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

1) The identification of the scope of the condition based maintenance rules: typically theCountries choose the safety related SSCs, SSCs which mitigates accidents or transients,
SSCs interacting with safety related SSCs, and SSCs that could cause scram or actuationof safety related systems. Therefore, many non-safety related SSCs may see theapplication of such maintenance rules, with augmented efforts in monitoring theirperformance and planning their reparation.
2) The setting of the performance goals for every component in the scope of themaintenance rules, ranking them according to their risk significance for the plant safety.
This task may end up very challenging as, when industry experience is not available,
either dedicated PSA tasks have to be developed (with special requirements on PSA
quality) or special qualification programs for the evaluation of the component reliability.
3) The performance monitoring techniques for the very broad categories of structuressystems and components in the scope of the rules.
4) The assessment of the safety during implementation of maintenance actions.
5) The feedback from the result of the monitoring of the component reliability back into theinspection, surveillance and maintenance procedures. Root cause analysis, equipment
performance trend analysis and corrective actions have to be developed on a case by casebasis.
In this sense for example the experience of the USA and Spain (where a LTO/PLEX program is wellestablished), Hungary, and Finland (where a PLIM model is in place at the Loviisa NPP) are aconfirmation of this generic statement: all these countries modified their regulatory requirements orpractice on maintenance, in the direction mentioned above, as one of the preconditions for the
LTO/PLEX of their plants.
The SENUF WG at the JRC carried out a detailed analysis on the experience of some of theabove mentioned countries on the interfaces between LTO/PLEX and maintenance programs, as a
background for the development of a state-of-art approach to modern maintenance programs. The
most relevant conclusions are summarized in the following chapters.
As summary of the Country practice in the field of MOPT, a quick questionnaire was run at one of
the above mentioned events organized in 2007 on maintenance optimization issues. The result issummarized in the following table 1.

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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management
Table 1 – Summary of the experience in selected European Countries on specific PLIM related issues

CountryType of Its scope M Optimisation Cost issues Reduction in in CDF
non-time (n.ofprocess in place included?
M cost after
based M systems)
M
RF
–
plans
RBMK100
CBM
5%
CBM
yes
5%
no
Hungary
Slovakia
CBM<10%
RCM - CBMyes
10-15%
n.a.
EMO

plans
plans
Ukraineplans
noBG– diagnostic Circ.
VVER1000
Pumps,
containme
nt, etc.
CR- CBM
Adaptive
yes
Dukovany
maintenancemodel,RCM,
cost benefit, useof PSA etc.
Cernavoda CBM

50% (all CBM analysis
safetyrelated)No, plans

Lithuania

<10%

no

CBM

CBM analysis

?

10%

no

37

in outage SFW used for M Network Indicator Risk monitor
duration planning/optimi ofspare s on M
available
sationparts
Desna/ Utility
10
Primavera
level
40 - 28
Passport / ?
No
1030
Yes on living
45 - 26
Arsoz/ WithPSA
Primavera
Bohunice
with
big
parts
Primaveranono
51 - 45
Primavera
With
Not
no
Temelinsistematic
ally
Overall
Passport/
yesdecrease Primavera / MNT48%
in Graph, use ofoutages Safety monitor
duration system
From 2 to
3 types
32 – 22, Passport
Few cases 10plans forwith Candu
20 (every
ownerstwo
10%
Fobos (IFS) / no~15
Primavera

Yes on living
PSA

Yes based onliving PSA

Yes, only forpipes (300 mm),main circulation
circuits

P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

In addition to that, Ukrainian, Slovenian, Czech, Russian representatives expressed in manyoccasions [4] their interest to adopt a MR-like approach in their Countries, even starting on a
voluntary bases, most probably closer to the ”equipment reliability” model (INPO AP-913, [36]).
Many of them already created some training centers which are developing procedures in this direction.
In conclusion, in relation to the operating cost reduction as a consequence of a kind of MOPT , thefollowing reductions [4] in maintenance costs/tasks were recorded:• In SWE, 10 - 20% of the effort, especially for I&C calibration intervals• In SP, 20% in work, 30% in number of tasks• In HUN, expected, not quantified• In CZ, 30% on a restricted number of systems selected for a benchmark (according to theimplemented Phare project in Dukovany NPP)
• In SKR, expected, not quantified.
It was noted that the “equipment reliability” program is not mandatory in most of the Countries(including the US). However, it is gaining growing interest for its systematic approach to the
management of the plant safety. In particular, the correlation among the many existing safety related
programs and the consistent classification of items (important, critical, run-to-failure) seems to be very
attractive and practical.
The main goals of the maintenance program in the framework of PLIM can be summarized as in thefollowing:• Assure plant safety• Maintain optimal plant availability• Optimize operation and maintenance costs• Assure and develop industrial safety• Comply with codes, legislation and regulation• Decrease failures of safety and availability critical components• Find and implement performance improvements• Increase the reliability and maintainability of the machinery and the performance of
maintenance support• Increase the economical service life of equipment and plant
A precondition for a MS&I program to be effectively inserted into a PLIM architecture is that themaintenance program is continuously optimized on the basis of the risk importance of any structure,system an component (SSC), controlling the overall reliability of operation and preventing functional
failures.
One way of achieving this goal is the implementation of a rigorous SSC classification and theselection of the most appropriate maintenance tasks (and periodicity) for each type of equipment. The
classification should be based on the importance to safety and operation, requirements of nuclear
regulations, replacement costs, environmental risks and maintenance experience. Classification can bechanged based on operation and maintenance experience.
The maintenance unit should be responsible for executing and planning normal maintenance work,
carrying out the work in refurbishment and investment projects, carrying out inspections andperiodical tests, managing spare parts, organizing personnel training and enforcing an appropriate QA
system.
4. A unified proposal for a PLIM model integrating Maintenance Optimization
4.1.

Introduction

Previous sections highlighted the main issues behind the development of a PLIM model, its mainfeatures and the experience of few European and non-European Countries in this effort.
As a consequence, the JRC-IE researchers developed a preliminary version of a new PLIM model thatthey believe could significantly improve the performance of the European plants. A first draft of thismodel is available at [1].

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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

The model was subsequently validated at one European plant that is believed to have one of themost advanced PLIM model in place. As a result of the validation carried out at Loviisa NPP, a newmodel was developed and is shortly described in the following.
4.2.

PLIM objectives

PLIM can be defined as a program (or even a combination of programs and procedures) aiming at
a safe and cost-effective operation of a nuclear power plant in the longest possible time period.
In this sense, it represents a framework for optimized, day-to-day, decision making aiming at a plant
long-term operation with optimal utilization of resources.
In other words, PLIM objective is the development of a consistent framework program at the plant
which enables the plant• to produce electricity in a safe and responsible way by continuously improving the power
plant operation and safety• to secure an efficient generation portfolio
This objective is typically achieved with coordination of some key programs at the plant, such as:
operation, asset management, maintenance surveillance and inspection (MS&I), ageing management,
knowledge management, and nuclear safety.
4.3.

Approach to PLIM

In order to achieve the goals set up in the previous chapter, the PLIM program has to consider thefollowing main components (see Fig.2):
1. Nuclear safety and licensing
2. Production and economy (including fuel and waste management)
3. Human resources
The long term investment plan is the basic tool for managing the investment portfolio where all
the technical programs provide input.
The generic PLIM structure is the result of the integration of selected existing programs at the plant
and the development of suitable links and feedback loops.
In particular the following programs are directly coordinated by PLIM:• Maintenance, surveillance and inspection (MS&I), including control of human factors• Ageing management, component obsolescence and plant configuration control• Knowledge management• Asset management and investment planning
Plant modernization, power uprating, fuel management may also be part of PLIM, but they are notnecessarily implemented at all plants.
This concept is described in Fig.2, where the four main components of PLIM are highlighted in
the central program, the input and the output are in the vertical lines and other programs are listed in
the lateral boxes.

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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

Fig. 2. Approach to PLIM and interfaces with related programs

These programs should also meet specific pre-conditions on their main features, as discussed
above and summarized in Fig.3.

Fig.3. Preconditions for the key programs to be part of PLIM

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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

Other programs represent a generic background for PLIM, and exchange data with PLIM, butthey are not explicitly part of it, such as: operation, nuclear safety, fuel management, waste
management, licensing (including the continuous updating of the Safety Analysis Report),
engineering, etc.
At last, important programs may be based upon PLIM, but they are not part of it, such as: plantlife extension, license renewal, periodic safety review, plant upgrading (including power uprating),
public acceptance, etc.
From the technical standpoint, the approach to plant life management consists of:• Identification of critical systems, structures and components (SSCs) from the standpoint of theplant operation and safety• Classification of the identified SSCs
• Identification of loadings and ageing mechanisms• Development of method for the lifetime prediction• Identification and implementation of applicable ageing countermeasures• Feedback to MS&I programs and other relevant programs• Development of the investment planning
4.4.

PLIM Scope - Component classification

A consistent application of PLIM suggests the use of a dedicated component classification, where
safety, availability and cost issues contribute to form the criteria.
All structures, systems and components at the plant, regardless of their safety relevance, should
be covered by such classification.
According to the classification, a suitable grading of measures may be applied and therefore
different levels of MS&I and AMP, economic analysis etc. may be assigned.
A proposal (see also Fig.20 from [5]) may group different classes as in the following:• Class A: critical components and structures directly limiting the plant life with theiravailability/integrity, non replaceable. Example: reactor pressure vessel, steam generator,pressurizer, main coolant pump, containment structures. Example of MS&I strategy: fullscope monitoring and analysis of the degradation• Class B: critical components, systems and structures from the standpoint of their importanceto safety and their cost of replacement/reparation. Examples: primary circuit, high and low
pressure safety injection systems, feedwater system, condensers, turbine, generators, diesels.
Example of MS&I strategy: condition based MS&I
• Class C: sensitive components, systems and structures. Examples: nuclear intermediatecooling, sprinkler, drainage and vents, main steam line, residual heat removal, circulating andservice water systems, condenser cooling system. Example of MS&I strategy: preventive(time-based) MS&I
• Class D: other components and structures. Example: condenser purification system, auxiliary
boiler plant, drinking water supply, sewerage. Example of MS&I strategy: run-to-failure
It is noted that such approach is still quite heterogeneous, as it mixes up components, systems andspecial equipment. Therefore the proposed classification may be reviewed to provide a morehomogeneous approach that would make the interfaces with the maintenance classification or sparepart classification much easier and traceable, because more homogeneous.
For components in classes A,B,C, a sort of component "health certificate" is recommended forcontinuous review and upgrading by the system engineers. The certificate should make reference tothe design basis and should collect the results from the AMP, the operation and the ISI programs,
including the pending issues detected by previous tasks.
4.5.

The organizational structure that supports the PLIM – The system engineers

The PLIM program requires important changes in the traditional plant organization. In particular,
the following preparatory organizational tasks should be implemented:

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P.Contri/Research priorities at the European Commission
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and Nuclear Power Plant Life Management

Development of a PLIM supervision and coordination Unit
Nomination of System Engineers, full time in charge of selected systems, especially forClass Ao Identification of research and engineering specialists in different disciplines at the TSO
organization, ready to cooperate with the system engineers to address methodologicalissues, interpretation of results, interfaces with the scientific and engineering community,
etc.
System engineers are the main interpreters of the PLIM program at the plant; they should be
responsible for the life management of a particular system, structure or component. They represent thesystem "owners". These engineers are typically responsible for the following tasks [5]:• Preparation and control of inspection, monitoring and maintenance activities related tolife management of systems; structures and components critical to safety• Detection and assessment of aging mechanisms and effects• Preparation and implementation of improvements in the field of proactive maintenance.
• Maintain and populate the life management system• Update the information in the long range planning system• Keep updated the records of the component/system health status in the reference
documentation system• Guarantee the reporting
Some interfaces between the system engineers and other groups/depts. are particularly importantin the PLIM framework, namely
1. The operators: plant TS and OLC may be discussed and changed (with the due authorizations)as a consequence of detailed analysis of the operating experience and of the MS&I outcome.
2. The MS&I technicians: objectives, periodicity, scope and other attributes of the programs may
be agreed and modified
3. The Safety specialists (either on site or at the TSO): they own the plant safety analysis andtherefore all the acceptance criteria for ageing and degradation should be agreed and reviewed
with them
4. The technical support group: the decision to repair/replace/maintain a component or structure
is taken jointly and approved by the management group of the PLIM.
oo

5. Conclusions
The European Commission, especially in the framework of the EURATOM programme,
identified specific R&D priorities to be mainly addressed by “direct actions” managed by the Joint
Research Centre (JRC) in the field of the Plant Life Management of its nuclear facilities. The best
chance for implementation is given by the newly launched Framework Programme 7 (FP7), wherelarge coverage is given also to the nuclear safety issues. The activities under the current 7th FP (20072011) combine continued effort in the area of component structural integrity with several new
initiatives in the areas of maintenance optimization and risk-informed approaches.
The paper provides an analysis of the research actions already in progress at the European
Commission-Joint Research Center (EC-JRC) in the specific field of maintenance optimization,
through the most recent results of the research on a unified PLIM model in the EU, and intends toprovide a basis for a review of the research priorities.
From the preliminary results, a confirmation can be drawn on the unique capability of the EC for
coordinating European R&D in support of harmonized best practices for plant life management. The
continuous support of the network participants (increased in some cases of 50% in the year 2007)
show that the selected activities do reflect the priorities of the stakeholders, in particular plant
operators and national safety authorities, coherent with the JRCs mandate under the Euratom
framework programmes.

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P.Contri/Research priorities at the European Commission
in relation to Maintenance Optimisation
and Nuclear Power Plant Life Management

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