Energy and Power Engineering, 2013, 5, 269-273
doi:10.4236/epe.2013.54B052 Published Online July 2013 (http://www.scirp.org/journal/epe)
Automatic Modeling of Fault Tree for NuIEEE
Transactions on Power Electronics,Clear Power Safety
I&C Configuration
Shan Leng1, Bo Zhang1, We i Sun2, Zhiwu Guo2, Yichen Hao 1
1School of Energy and Environment, Southeast University, Nanjing, China
2Instrumentation and Control Institute, Guangdong Nuclear Power Engineering Corp. Shenzhen, China
Received April, 2013
ABSTRACT
The automatic modeling of fault tree for nuclear power safety I&C configuration is designed to meet the requirements
of reducing the workload and improving the traceability during the nuclear power safety I&C system reliability assess-
ment work. To complete the fault tree automatic modeling, the Visio Automation software technology is used to ana-
lyze the topology of the nuclear power safety I&C system hardware device and software function. The good result in
practical implementations shows that the nuclear power safety I&C system fault tree modeling work is successfully
simplified.
Keywords: Nuclear Power Safety I&C System; Visio Automation; Automatic Modeling
1. Introduction
This paper takes nuclear power safety Instrumentation
and Control system, or I&C system for short, as the mod-
eling object. Safety I&C system, a crucial part of the nu-
clear power plant, guarantees safety, reliability and eco-
nomic efficiency. Considering the distinctive features of
nuclear power plant, safety and reliability of all nuclear
power systems must be verified with no exception of the
very important nuclear power safety I&C system. In or-
dinary verification modeling process, fault trees are built
manually after analyzing the topology of hardware and
the function of the software, which becomes not only
time-consuming, but also inconsistent with style, coding,
assumption and other factors. To make it worse, the er-
rors usually occur during the manual modeling process
gradually. Furthermore, today the whole process of the
fault tree modeling is required to be recorded for the
reason of simplicity and traceability, which makes man-
ual modeling workload of fault tree for nuclear safety
I&C system heavy and cumbersome. In order to solv e the
problems above, the automatic modeling methods need
to be conside red [1, 2, 7] .
In this paper, Visio Automation software technology is
used to analyze the topology of the nuclear power safety
I&C system hardware device and software function to
complete the fault tree automatic modeling work [6]. The
good result in practical implementations shows that the
nuclear power safety I&C system fault tree modeling
work is successfully simplified.
2. Automatic Modeling of Fault Tree
According to the designing concept of automatic model-
ing system of fault tree for nuclear power safety I&C
configuration, the structure of automatic modeling proc-
ess is shown in Figure 1. The new developed modeling
system is divided into three main parts: configuration
module stencils, configuration drawing and fault tree
automatic generation.
Figure 1. Structure of automatic modeling process.

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270
2.1. Stencils Design
In this paper, nuclear power safety I&C configuration
work require to create the Visio visualization stencils,
according to the respective characteristics of nuclear
power safety I&C system hardware device and software
function, ActiveX control technology is used to create
the card and logic ga tes module stencils for configur ation.
The created module stencils is shown in Table 1. User
can drag and drop the module in the stencils and draw the
signal line in the configuration diagram. After the nuclear
power safety I&C configuration diagram is completed,
User can use Visio Automation mechanism to get the
IDispatch scheduling interface of ActiveX control, the
control’s properties, methods and response control events
can be accessed. After analyzing the configuration dia-
grams, the automatic modeling system of fault tree will
lead anticipated results [8].
Table 1. Stencil mudule.
Type ActiveX control Description
I&C Card KLPJ Distribution module card
MRPJ Repeater card
PFBJ Intelligent I/O bus master card
PCPJ CPU card
MEOJ Optical conversion card
PSMJ System management card
PWNJ W-net network I/F card
MDOJ Digital output card
PPNJ System switchove r unit
Logic Gate 2/3 Two from three
2/4 Two from four
AND And gate
OR Or gate
Transmitter Level transmitter
Digital transmitter
Limiter Limiter
2.2. Configuration Object Feature
After configuration drawing is finished, a new Visio Au-
tomation program will be needed to analyze the con-
figuration diagram through the object model which con-
tains the attributes, methods, events and hierarchical re-
lationship between the objects. The Visio objects struc-
ture is shown in Figure 2. Built on the Visio Automation
programming resources, the topmost object acts as an
application object (Application). Through the Applica-
tion user can access to any other objects. User can use
the object’s properties and methods to perform certain
operations after obtain the object reference and identify
the features. According to the features of different ob-
jects, the objects can be classified as shown in Table 1.
Different types of objects must assigned different proper-
ties and methods.
2.3. Process of Automatic Modeling
In this paper, the automatic modelin g system of fault tree
for nuclear power safety I&C configuration is built b ased
on Visio Automation software technology. This technol-
ogy allows user to extend the visualization functionality
of Visio or make it as user program’s graphics engine.
User can not only create or modify the configuration di-
agrams based on external data, but also extract the rele-
vant configuration information from diagrams by a spe-
cial designed program [1]. In this paper, VC program-
ming language is used to write VSL library file [6], and
run in the way of sharing the same address space with the
graphics engine. This method has strong ability to inter-
act with configuration diagrams and high operating effi-
ciency.
The concept of control stream is used to analyze the
nuclear power safety I&C configuration diagram during
the automatic modeling processing. The fault courses and
results transfer in complex I&C configuration system
following the way of control streams. The configuration
diagram is analyzed based on control streams to organize
Figure 2. Visio objects structure.

S. LENG ET AL. 271
and classify the information modules. An analysis pro-
gram is designed to complete the automatic modeling
process.
1) User needs to co mplete the drawing work of device
configuration, user use the created module stencils and
signal line class to complete the configuration diagram.
After the completion of the diagram, assignment function
of the form class is used to complete the assignment of
the common cause group and module in configuration
diagram. According to the objects classification in Table
1, different types of objects must assigned different
properties and methods.
2) After the connection relation is checked, user can
analyze the configuration diagram. Visio Automation
software technology is used to get the object and its
properties and methods. The process of analysis is shown
as the automatic modeling part in Figure 1. At beginning,
the program gets the signal line, then the up- stream and
downstream information module is obtained. Then user
can analyze the feature of object to get the properties and
methods. After the analysis of the module and connection
relations and taking the failure mode into accoun t, a fault
tree file is generated.
3) User inputs the fault tree files through the interface
with Risk Spectrum, the nuclear power safety I&C sys-
tem configuration fault tree analysis work is completed.
3. Safety Configurations Implementation
In this paper, the automatic modeling method is used to
simplify the modeling work of fault tree for nuclear
power safety I&C configuration. The fault tree files are
generated follow the process of automatic modeling, the
structure of the process is shown in Figure 1. After the
fault tree is built, the correctness of automatic modeling
of fault tree must be verified. The implementation can be
divided into two typical parts: the measurement signals
configuration and channel group configuration. After the
implementation, the accuracy of automatic modeling
work is verified deeply and comprehensively.
3.1. Measurement Signals Configuration
The measurement signals configuration is very typical in
nuclear power safety I&C configuration system. Figure
3 shows the measurement signals configuration diagram.
This diagram has three LT transmitters, three KLPJ cards
and a logic gate. In order to complete this diagram, user
can drag and drop the module in the stencils and draw the
signal lines to connect modules. The completed diagram
is shown in Figure 3. The fault tree file is generated after
analysis of the configuration diagram. The created fault
tree is shown in Figure 4. In this figure, the Top Event
corresponds to the logic gate, a KLPJ card generates two
Basic Events and an OR Gate, the LT transmitter is in the
same situation with cards. The generated fault tree of the
measurement signals configuration is proven correct, that
means the accuracy of the automatic modeling work is
preliminary confirmed.
3.2. Channel Groups Configuration
The nuclear power safety I&C system has a lot of chan-
nels, the structur e of the channels are b asically the same.
Each channel is divided into A, B groups, the structure of
the two groups is identical. Th e intermediate portion of a
channel group A configuration diagram is shown in Fig-
ure 5. The signals of group A and B converges in PPNJ
cards. This channel groups configuration is very common
with the I&C configuration system.
The fault tree is generated after analyze the channel
groups configuration diagram. Because the overall fault
tree is too large, only part of the fault tree is shown in
Figure 6, this part is begin with the group A Limiter
cards and MEOJ cards ,through the set of K/N logic gates
the signal transmitted to the AND gate.
LT LT
LT
KLPJ
KLPJ
KLPJ
2/3
Figure 3. Measurement signals configuration diagram.
Figure 4. Fault tree of measurement signals.

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272
OR
2/3 2/3
2/3
2/3 2/3
MRPJ
PFBJ
PCPJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
MEOJ
2/4
AND
PFBJ
PWNJ
MDOJ
PPNJ
PSMJ
MEOJ
Figure 5. Channel groups configuration diagram.
Figure 6. Fault tree of part of channel groups (a).
Figure 7 shows the fault tree which is begin with
AND output signal, through the PSMJ card and PWNJ
card, the PWNJ output signal merge with the signal of
group B to PPNJ card. The Top Event is the generated
gate by PPNJ card, the input signal is the AND gate. The
correctness of the automatic modeling system has been
verified comprehensively.
Figure 7. Fault tree of part of the channel groups (b).
4. Conclusions
In this paper, ActiveX control technology is used to cre-
ate the module stencil for configuration and VSL library
written in VC language is used as a tool to analyze nu-
clear power safety I&C system hardware device and
software function to build the fault tree. The successful
implementation of automatic modeling of fault tree has
verified the correctness of the automatically generated
fault tree. The method of the automatic modeling of fault
tree for nuclear power safety I&C configuration simpli-
fies the modeling work and improves the traceability of
the fault tree modeling. This method has been applied to
practical work, and with some modifications it can also
be applied to other systems such as the logic diagram
analysis of electrical system and information system.
Therefore, the method of fault tree au tomatic modeling is
bound to have broad application prospects.
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