Study for Modeling of Control and Condition Monitoring Integrated ...symbio-newsreport.jpn.org ›...

Science and Technology on Reactor System Design Technology Laboratory

NUCLEAR POWER INSTITUTE OF CHINA

Study for Modeling of Control and Condition Monitoring

Integrated System for Nuclear Power Plant

Chen Zhi, Yu Ren, Zhang Ying, Liao Long-tao

NUCLEAR POWER INSTITUTE OF CHINA -2- 2012/9/23

Outlines

Introduction

The overall scheme of the control and condition

monitoring integrated system

Control and condition monitoring integrated

system modeling

Conclusions


Introduction (1/2)

The Three Mile Island accident occurred in the 1970s revealed that in order to improve NPP safety and automation level, it is necessary to develop appropriate operation support system (OSS), helping the operator to implement the plant running manipulation better according to the current plant conditions.

Some operation support and condition monitoring systems have been developed: — REACTOR (United States ) — DISKET (Japan ) — ESPED (Korea )

The development of the OSS system provides more guarantee for the NPP.


Introduction (2/2)

But previous reports indicated that the plant control system and the condition monitoring system to provide support for the operator are designed separately in the most nuclear power plants at present, so

system compatibility,

system resources utilization efficiency

system's extensibility and support for real-time, etc.

is affected, and may have a negative impact on the operation of NPPs .

NPIC and the other university of china are collaboratively developing an new system to perform the control and support functions better. In this presentation, the general scheme of the control and condition monitoring integrated system is introduced.

The modeling study is also carried out by using the IDEF0 (Integration Definition Language 0) and UCM (Use Case Maps) methods for the integrated system.

Try to solve above problem


The overall scheme of the integrated system(1/10)

1. The function analysis of the integrated system According to the requirements analysis for the nuclear power plant control system and condition monitoring system, the main functions of the integrated are as follows:

a. Data acquisition and management Data acquisition and management are the bases for control and protection, condition monitoring and evaluation and operational decisions.

Data acquisition and management function realizes real-time acquisition of the site parameter information of NPP and sends the information to the relevant equipment to be stored and processed.Then the information can be used by the various subsystems of the integrated system. . b. Control and protection The control and protection function implement the corresponding control and protection action according to the site parameter information, plant operation state and operator command in order to assure the safety and reliability of the NPP.



c. Critical-safety function monitoring indicates that the current safety state of NPP;

informs the operator quickly once there were some changes which occurred on the important safety state .

Thus helping the operator make the decision quickly and accurately.

According to the safety principle of "defense in depth" for NPP, the six important safety functions should be maintained simultaneously: reactivity control, core cooling, coolant capacity of the primary side, water capacity of the secondary side, the pressure boundary integrity and the integrity of the containment.

In order to monitor the status of the above six safety functions, it is very important to select the correlative parameters properly in the design of the integrated system.



d. Running conditon assessment and fault diagnosis execute the functions of the analysis and the feature extraction for the acquisition parameters and status parameters

then determine the system's running condition and carry out fault diagnosis.

The system can check the status of the key equipment and engineering safety features (ESF), read the real-time data in the parameter database, evaluate the running condition of NPP and display the analysis results on the human-machine interface. The integrated system also can analyze the parameter changes in the process of plant systems and equipment running and engender the alarm information when the running state deviates from the normal trajectory, thus reminding the operating personnel to pay attention to the related equipment and system status.



e. Operation guidance The maintenance and system testing before the startup, after the shutdown and in the routine running of the NPP are relatively heavy, but very important work.

By instructing operating personnel to accomplish these tasks with the integrated system,

the burden of operating personnel can be reduced,

the status monitoring for the systems and equipment can be realized automatically.



Data acquisition

Object to be controlled and monitored in NPP

Parameter trend and sequence analysis

Status knowledge database

Human-machine interface

Operation scheme

database

Operators

Operation knowledge database

Operation situation

monitoring

Abnormal status

detection

Degraded degree

analsyis

System status assessment

and identification

System model

database

Fault diagnosis

Fault orientation

Cause analysis

Consequence evaluation

Evolution forecast

Operation guidance

Normal operation

handle decision

Emergency handle decision

Non-safety handle

detection and restriction

Control and protection

Safety-critical function

monitoring

Fig.1 The function composition scheme of the integrated system



2. System hardware and software requirements The control and condition monitoring integrated system of NPP will implement the comprehensive control and condition monitoring of the plant, and give the operator manipulate and operation decision-making support.

So its software and hardware systems must meet the following three basic requirements: 1) Reliability requirements

3) System flexibility and maintenance convenience requirements

2) Real-time requirements



Reliability requirements a. The computer used for condition monitoring and its power supply should be considered to

be redundant. b. The integrated system must work in normal and abnormal operating conditions. c. The malfunction of the non-safety equipment providing information to the integrated

system, shall not affect the ability of processing the required safety information of the integrated system.

Real-time requirements a. acquire the real-time data from the site, process data and analyze data; b. respond to abnormal events in a limited time. c. The manner of inputting data by manual should be simple and quick. d. Rapid completion of the operational guidance, alarms, historical data records are required. e. The reasoning mechanism is as simple and efficient as possible and the size of the

knowledge database should not be too much.



System flexibility and maintenance convenience requirements a. Users can query, set the parameter and modify the control rules easily.

b. HMI can be achieved

c. When the system is failure or on unusual circumstances, the system itself can take the

appropriate measures or ask for the introduction of the necessary human intervention



Basic design principles:

System architecture,

human-machine interface,

control and condition monitoring policy, subsystem settings

the system functions realization methods

3. System character and configuration

must be integrated and unified.



Sensor and actuator device

Control and protection system

Information process and

display system

Operation status assessment and fault diagnosis

system

Operation assistant decision system

Manipulation guidance system

Monitoring and detection

Situation assessment

Response planning

Response implementation

Human-machine interface

Operators

I&Csystem

Object to be controlled and monitored in NPP

Fig.2 The overall framework scheme of the integrated system

The characteristic features of the integrated system will be mainly reflected in the following four aspects : Goals integration The integrated system should be designed and developed collaboratively. Functional integration The design should take into account the cross and overlap in function between the various subsystems. Physical structure integration Uniformity in the structure avoids duplication and inconsistencies of the system modules, thus ensuring compatibility between man and machines and among subsystems. Information integration The integrated system will undertook more comprehensive information processing and analysis methods to improve information display, transmission and switching forms.


Control and condition monitoring integrated system modeling(1/13)

1. Modeling methods

1) Structured modeling methods IDEF0

The structured modeling method is the method oriented system architecture and based on data flow and function. On the whole, it is a top-down modeling methods.

IDEF0 (Integration Definition Language 0) is a family of IDEF method and its basic idea is to make the user can understand the function and operation of the system through a graphical expression.

IDEF0 model is made up of graphics, text, vocabulary table and mutual cross-reference table, of which the graphics is the main component.

The IDEF0 graphics is always made up of an activity model, an information model and a user interface model, when it is used to express a current operation, functional description or design .



Fig.3 The graphical structure diagram of IDEF0 model

Function/ActivityInputOriginal material

Original data

Control

Decision rules

Task parameters

OutputProduct information

Mechanism

DevicePersonnel

Input: resource changed or consumed by the activities.

Control: restrictions in activities operating

Output : the output result of the activity

Mechanism : which execute or actuate the activities

The main modeling steps of application IDEF0 method are as follows: 1) Select the scope, the views or purpose; 2) Establish internal and external relationship diagram (A-O diagram); 3) Draw the top-level diagram (A0 diagram); 4) Establish a series of graphic; 5) Create a text description.



UCM (use case maps) is a typical modeling method based on scene.

UCM describes the behavior and composition of the system, as well as the relationships between them in one chart in the view of the entire system. When the UCM is used for system modeling, the level of abstraction is relatively high. details within the system do not fully be hidden. Therefore, this gray box manner makes UCM have considerable flexibility in the expression of the system architecture.

2) The based on scene modeling method UCM



The basic elements of the UCM modeling methods are the path, the components and responsibility. Path: the ordered sequence of causal responsibility. Components: refers to software or hardware components, also can be human participants or other systems. Responsibility: the abstraction of actions, activities, operations and tasks performed by the component. The basic idea of the UCM modeling methods is based on the causal relationship of the responsibility executed by components to describe the scene path

Start point

End point Path Basic path

Or-join Or-fork And-join And-fork

Responsibility

Component

Fig.4 The elementary symbols of UCM model



3) IDEF0/UCM integrated modeling methods

The IDEF0 method — is suitable to describe the system function composition and flow of information within the system. — lacks the enough expression ability for describing the dynamic model and can not describe the implementation process of a specific function.

UCM method — can clearly describe the dynamic behavior of the system and make the designer understand the system on the overall. — is not suitable to describe the flow of information within the system.

Therefore, integrating the two methods, using the UCM describe the dynamic behavior of the system, and describing the system functions and information flow by IDEF0 method, it is better to model and analyze the system.



According to the needs of the integrated system modeling, this study will use IDEF0 and

UCM integrated methods to modeling.

The IDEF0 method is used to analyze overall system, express system activity and data flow

as well as the links between them, and describe the system functional requirements. UCM

method is used to describe the system behavior and composition as well as the relationships

between them.



2. Integrated system modeling based on the IDEF0/UCM integrated methods

1) The overall system model

The internal and external relationship diagram A-O established by using the IDEF0 method, as shown in Fig.5.

Integrated control and condition monitoring

systemI2:

Measured parameter

Operator instruction

Actuation singal

HMI informationI1:

O2:

C1

M1

O1:

I3: Required database

Theory and method

Software and hardware resource

Fig.5 The internal and external relationship diagram of the integrated system



On the basis of the relationship A-O map, and analyze the dynamic causal relationship between the activities of the various functions of the integrated system, the UCM model of the overall system is shown in Fig.6.

Fig.6 The overall UCM model diagram of the integrated system

Statusassessment

Fault diagnosis program

Hmuan-machine interface

Parameter and condition information

Data acquire equipment

HMI equipment

Data acquire

Control and protection

Control andProtection equipment Actuation

Actuation device

Statusassessment

program

Fault diagnosis

Manipulation guidance

Manipulation guidance program



Combined with the internal and external relationship A-O diagram

The components in the overall UCM model are mapped to functional modules of the IDEF0 model

the system top-level IDEF0 model diagram, A0 diagram, can be established,



Fig.7 The top-level A0 function diagram of the integrated system

A2

A6

A3

I1 Measured parameter

Data collection module

A1

O1 Nuclear and process parameter

Control and protection module

Alarm signal

O22 Equipment condition informantion

Condition monitoring and assessment module

O3 Conditon, alarm, fault ,and aided computation information

I2 Operator instruction

I3 Required database

C 1 Theory and method

Data management module

O4 Conditon, parameter and alarm information

O21 Control and protection signal

A4

A5

Human-machine interface module

Expert knowledge and instruction

M1 Software and hardware enviroment

O5 HMI information

Operator instruction

Device actuation module

O6 Actuation signal

O2

O21 O22

The system is divided into six sub-modules

Six sub-modules: data acquisition module, control and protection module, condition monitoring and assessment module, data management module, human-machine interface module, device actuation module



2) IDEF0 and UCM model of the system module

In order to analyze the functional modules in the A0 diagram more in detail, the further decomposition of the various modules should be needed to get the IDEF0 model sub-graph. The modules can not be breakdown further by the IDEF0 method will be modeled by the UCM method. The condition monitoring and assessment module is taken as an example to describe this process.

A31

A32

A33

C11 C12 C13

M1

A35

A34

I1 Process parameter

I2 Nuclear parameter

I3 Alarm signal

Condition monitoring method

Equipment work condition monitoring

System running condition assessment

Condition assessment method

Alarm analysis method

32O2 Alarm signal

31O Equipment condition information

32O1 System running condition information

Software and hardware enviroment

Alarm process module

Fault diagnosismodule

33O Alarm information

34O Fault information

Auxiliary calculationmodule

35O Auxiliary calculationinformation

Fig.8 The diagram of the condition monitoring and assessment module

The condition monitoring and assessment module can be further divided into five functional modules



Fig.9 The diagram of the equipment work condition monitoring module

C11

M1

A311

A313

I1 Process parameter

Condition monitoring method

Condition monitoringbefore startup

311O Condition information

A312

Primary system equipment running

condition monitoring

Control and protection system equipment running condition

monitoring

312O Primary system equipment runningcondition information

313O Control and protection system equipment running condition information

Software and hardware enviroment

The equipment work condition monitoring module in Fig.8 can be decomposed further by using IDEF0 method.

Equipment work condition monitoring module completes the following functions: 1) The status check before reactor startup; 2) The supply voltage check for the important equipment ; 3) Work condition signal check of the control and protection system



Fig.9 The UCM diagram of the primary system equipment condition monitoring

The primary system equipment running condition monitoring module A312 , which is shown in Fig.9, as the basic functional unit can not be decomposed further. Their activities can be described by the UCM method.

Running parameterInput interface

Parameteracquisition

Computer program

Running conditionidentification [abnormal]

[normal]

Alarm signaloutput

Condition informationoutput

Output interface


Conclusions

In this paper, the study of the function composition, information requirements and the overall scheme of the control and condition monitoring integrated system is carried out. A method of combining IDEF0 and UCM is selected to establish system model. The corresponding method and analyzing process in this study can provide the reference for the development of the integrated system of real NPP. Furthermore, the modeling results in this study can be used in the detailed design of the integrated system of NPP. Because the study is still at a preliminary stage, the following work should be done in the next step: 1）Based on the specific objects of NPP, the further refinement for the model should be completed in order to describe the relationship between input and output of the system model in detail; 2) The appropriate software and hardware should be selected to establish the prototype or demonstration system to verify the correctness and rationality of the analysis and design results; 3) The specific realization methods, especially the programming method, need to be studied in order to develop the system smoothly.


Thank you for your attention!

Study for Modeling of Control and Condition Monitoring Integrated ...symbio-newsreport.jpn.org ›...

Documents

Transcript of Study for Modeling of Control and Condition Monitoring Integrated ...symbio-newsreport.jpn.org ›...