Anne Dour
EDF R&D, 6 quai Watier, 78401 Chatou cedex, France
Eunika Mercie
EML Knowledge Management & Innovation, 620 Chemin des Grives, 34160 St Drezery, France
Christophe Roche
University of Savoie, team Condillac, Campus scientifique 73376 Le Bourget du Lac cedex, France
Keywords: Ontology, Knowledge Manag
ement, Common language
Abstract: The French nuclear industry deals with technologies which will soon be thirty years old. If such
technologies are not renewed they must last for another ten years- or more if the decision is taken to keep
them working. There is a risk of technological obsolescence- something which is allowed for in other
national and international projects. There is also the question of constant commercial demand- something
also considered elsewhere in establishing contracts. Another problem is now beginning to emerge; the
continuity and transmission of knowledge and experience concerning these plants. Personnel in the energy
sector are being renewed. Most current employees are due to retire in the course of this decade. How is
knowledge (both of maintenance and planning) to be transmitted to the new generations ? This knowledge
includes written information but also know-how and implicit working assumptions; expertise, experience,
self-learning. In the United States the EPRI produced a technical dossier [EPRI 1]. The problem of
knowledge of old technologies is therefore recent, but almost universal. As far as EDF knows, nobody is
considering this subject in its entirety. Instead, each technology puts the emphasis on operation (and thus
safety) according to a fixed timetable (ten-year visits, end of use). In this perspective the initial knowledge
can be lost. It can happen, for example, that the need for renewal can oblige the agency to carry out a costly
or difficult retro-engineering project so as to recover the original knowledge and technology. If we look
ahead, the policy of long term development (notably extending the life of plants) requires us to consider the
life-span of the different skills and knowledge required by each environment. So it is necessary to take into
account the entire life cycle of a nuclear installation. We are working on organizing all this knowledge and
building an innovating solution for easy acquisition, access and sharing knowledge and experiences. First
we are creating an ontology-based common language for all involved and defining some applications on
Intranet. Ontology, understood as an agreed vocabulary of common terms and meanings shared by a group
of people, is a means for representing craft concepts upon which knowledge can be organised and classified.
We shall present one of the first applications based on the Logic Diagrams Designer's ontology whose main
goals are to keep in memory the craft knowledge about relay circuits schemas and to allow accessing and
retrieval information. This choice of ontology as a basis provides an easy and relevant navigation, indexing
and search of documents...
The French electricity generation capacity includes
58 PWR nuclear plants in operation, in 3 power
levels (900 MW, 13000 MW and 1450 MW) and 6
reactor types, that is of the same design.
In terms of life cycle management, the EDF general
is to operate nuclear power plants for 40
years at least. For a operating life of 30 years, the
personnel who took part in the design and
commissioning of units are still with EDF, which
will not be the case for much longer. With time,
modifications to units become increasingly
Dourgnon-Hanoune A., Mercier-Laurent E. and Roche C. (2005).
In Proceedings of the Seventh International Conference on Enterprise Information Systems, pages 323-326
DOI: 10.5220/0002512303230326
significant and may lead to partial redesign, which
requires total mastery of the design and justifications
of the choices made. The ageing management
programme includes therefore a long-term
maintenance of knowledge approach to "pass the
baton" to those generations who did not take part in
the original design choices or construction.
This problem is shared with other utility companies.
It is covered by the Euratom programme.
In the USA, where the loss of knowledge and of
undocumented know-how has been identified in the
Energy sector, a study [EPRI 1] noted the risk of the
disappearance of knowledge, particularly knowledge
of design and modifications, which concern us here.
It also raises the question of the maintenance of
knowledge of feedback, but this is subject to a
specific organisation in France.
2.1 The I&C of 900 MW power plants
Relay technology is highly significant for
instrumentation and control (I&C) in the oldest
nuclear units of the French reactor stock, the 900
MW nuclear power plants (NPP), where there are
tens of thousands of relay circuits, involved in all
functions. The traceability of documentation (design,
modifications, feedback) has always been very
In so far as design documentation is concerned, it
mainly dates back to end of the 1970's, the period of
construction and commissioning of the 900 MW
power plants. The engineers (operation,
instrumentation, automatic control) who were at the
start of the design of these power plants, are coming
to the end of their careers.
2.2 Knowledge of relay circuits
The first of the players, the operator, has no worries
with relay systems: the relay circuits has not
changed, they have aged a little, but its excellent
reliability has protected it from modifications and
replacements. The documents are as is, hardly ever
amended but often reproduced. The installations
themselves change little, therefore modifications are
When knowledge is no longer put into practice, it
tends to be forgotten. Therefore, in operation,
knowledge appears to crystallise on components,
boards and relays. The overview of the installation is
less important, the "memory of installations"
(design, modifications) often disappears as
personnel leave.
Engineering offices are the guardians of "the
memory of installations". This memory is in the
extensive and highly diverse documentation
(functional design diagrams, logic specification
diagrams and wiring diagrams …), accessible in
CAD systems. The design of these diagrams is given
in writing, but know-how is transmitted orally,
through training sessions or apprenticeships.
The memory of installations "goes down" to the
memory of equipment. In this case, the combination
is very important, given the large number of
equipment configurations and their use. Once again,
oral know-how of the options adopted during the
design phase and the choice of modifications is
important; it is often heuristics that limit or classify
Essential knowledge is therefore of two kinds; semi-
formal representation on the one hand (design,
specification, production rules and forms of
representation of diagrams) and, on the other,
practical oral knowledge of the interpretation of
previous knowledge. This is what interests us.
3.1 Our approach
The awareness of this very important combination
and an initial analysis of knowledge has enabled us
to avoid two pitfalls; that of non standardised
modelling [we use standard ISO 704], without a
consistency check, and preliminary, non modifiable
modelling. As we shall see below, we have
linearised the problem by describing it in the form of
a tree-structure and not a graph. This modelling is
incremental and involves all players.
The questions which will be raised over the next 10
years and beyond, are partially unknown. The first
stage for us, ensuring that the knowledge of relay
circuits could make sense later, was to ensure that
they are shared, whatever the situation, profession
and activities of all those concerned, whether in a
context of preserving or renewing technology. The
last pitfall, and not the least, would be not to make
such knowledge independent of the context. We
shall also see how the solution adopted meets this
As in any capitalisation, valorisation and of transfer
of knowledge approach, the first stage consists in
defining, in detail, the trade terminology. That is, the
terms used and their meaning, which constitute a
common language giving access to professional
concepts and the corresponding documentation.
3.2 The Logic Diagrams Designer’s
The objectives of consensus, consistency and
sharing for the common language have led us to
choose a solution based on ontology. Ontology as an
agreed vocabulary of common terms and meanings
shared by a group of people, is a means for
representing business concepts according to which
knowledge can be organised and classified.
The profession of the 900 MW Logic Diagrams
Designers that we have adopted for this experiment,
like professions in the nuclear industry in general,
imposes severe restrictions as to the definition of its
terminology: the definition of terms should be
precise and consistent with the logical meaning of
the term. It should also be based on a construction
methodology and can be understood and accepted by
those in the trade, be they experts or novices in
It is for this reason that we have adopted an
ontological approach where professional concepts
are defined by specific differentiation: a professional
concept is defined on the basis of an existing
concept by identifying what distinguishes it.
Therefore, a "functional logic diagram" is a
"functional diagram" which is "logical". "Functional
diagrams" are therefore broken down into "
functional logic diagrams" and "analogue functional
diagrams", "logic" and "analogue" being two
specific, opposing differences.
Such an approach has many advantages :
a linguistic base as shown by the structure of
the professional expressions themselves;
an epistemological base: everybody can
agree with the specific-difference definition
where concept A is concept B with the
specific difference d;
no multiple hierarchy and therefore no
problem of inheritance of different values;
sound logical properties which are exploited
during the building of ontology;
last but not least, the agreement problem is reduced
to the sole problem of agreement on the terms that
denote differences. It is all the simpler since the
application field is technical.
3.3 Ontological indexing and retrieval
We have already seen that ontologies may be used to
model and capitalise on professional concepts for
which it is possible to define the terminology for the
field in a precise, consistent and consensual manner.
Ontologies may also be used to index all documents
on the field to such concepts for the purposes of
training but also for finding information.
We have therefore created, after defining the
ontology of the Logic Diagrams Designers of 900
MW Relay circuits, an experimental software
environment devoted to terminology on the one hand
and business concepts and, on the other to the search
for and navigation through documents that refer to
such concepts. The figures below illustrate some of
the functions of the software environment accessible
on the EDF intranet.
Functional diagram
Logic analogue
Logic Functional Diagram Analogue Functional Diagram
Rra logic rra a-logic rra analogue rra a-analogue
RRA Functional Logic Diagram anonymous28 RRA Analogue Functional Diagram anonymous29
ure 1: Exam
le of an ontolo
ure 2: Some of the functions of the software environment
Overall flow is created step by step by creating
exchanges which progress from exchanges based on
documents, photographs, glossary to achieve a true
sharing of knowledge and knowledge of equipment,
functional aspects and diagrams.
Our incremental construction approach for a
common solution has the advantage of providing for
virtually automatic acceptance of the system
proposed by all participants and which we have to
validate. This approach is modular and provides for
the gradual construction of a common reference
Ontology is the basis of this language, which enables
us to model knowledge of professions involved in
relay circuits and to ensure appropriate access to
aspects of knowledge, such as documents, diagrams,
photographs, training documents… at the same time.
This language shall form the basis for effective
communication in a global flow knowledge created
by the participation of communities concerned with
relay circuits and others who wish to learn.
Amidon D.M., Formica P., and Mercier-Laurent E. :
Global Knowledge Innovation at work. (soon)
Ballay J.F. , 1997 : Capitaliser et transmettre le savoir-
faire de l'entreprise, Editions d'Organisation
Ballay J.F. , 2002 : Tous managers du savoir ! , Editions
EPRI, December 2002 : Capturing high value
undocumented knowledge in the Nuclear Industry. In
Guidelines and methods 1002896 Final report.
Gruber T., 1995 : Towards principles for the design of
ontologies used for knowledge sharing. In:
International Journal of Human Computer Studies, 43: