|POE (Nuclear Emergency Operations Plan Manager)|
Nuclear Plant of Cofrentes (Valencia, SPAIN)
||Provided training to 2 technicians of the Nuclear Plant (6 months).|
Developed and delivered a prototype in KEE on a TI-Explorer, during 1989
POE is a system designed to assist a Nuclear Plant operator who has to verify a sequence of complex operations and decisions when an Emergency Situation arises.
The system has a powerful graphical interface that simulates the existing tools and usages and allows a quick access to the relevant information.
Advanced tools and concepts based on Object Oriented Programming have been used in order to easy the maintenance and future integration of modules with more "intelligent" functionalities.
By now the operator who works in the control room of a Nuclear Plant has several printed diagrams that he can consult when a determined Emergency Condition triggers.
Such diagrams are periodically revised and validated by means of test and simulations. Its design is based upon a representation by standard symbols of a series of interrelated items: conditions (parameters taken from different subsystems related with the incident), operations, explicative texts and help tables, graphics and curves, preventive measures,...
The complexity of the graphics due to their crossed references and the way they are used, could increase the psychological pressure on the operator if one of these alarm situation arises and difficult the processes of decision making and operation supervision.
A system that will allow the operator to concentrate his attention on the really relevant information, would easy his job and indirectly would increase the security levels.
A) Knowledge Representation
A first step in the solution design was considering the concepts handle by the operator in the decision process.
On the one hand, there are several engines and parameters implied in each of the possible iterations. The values of these physic parameters would be supplied for sensors connected in real time to it.
On the other hand the more important concepts involved in the process of diagram understanding were selected.
B) Process Control
Basically two operations modes were considered:
- A semiautomatic mode, based on the continuous reading of external signals which can modify two or more reasoning paths in a given moment. Anyway the human operators keeps always the control.
- A manual mode. In this case the operator is the only source of information that makes progress the decision process.
He will also be able to ask for help, access tables and curves (Fig.2), show a trace with all the system answers and operations to be executed, inspect the different ways opened simultaneously or if necessary go back in any of the intermediate situations of the process followed until that moment.
C) User Interaction
When an operator will consult the diagram implemented on the computer, he will find basically the same diagrams that he usually handles (Fig.3). He has only to push the mouse buttons over the screen icons to browse rapid and easily over this diagrams and answer to the conditions opened in a given moment. The more important messages will be shown automatically (Fig.4).
This way, some important problems that the introduction of computers in the day-to-day work of these operators will be eliminated:
- On the one hand, the "allergy" to the keyboard that determines a negative attitude to the system that forces a new, complex, not human way of communication will be controlled.
- In addition the user will not need to learn a new language, keeping the same symbolic and operative environment that he has always used.
The new symbols (icons) and operations (push the mouse buttons on determined positions) are few and very simple.
The development of a prototype has taken three working months for two programmers that at the same time were acquiring their first experience in the use of the employed tools (KEE on the Explorer), assisted by a knowledge engineer.
Fig. 1: Nuclear Plant Main Parameters & Alarms
This screen shows the diagram of the Nuclear
Plant, with the sensors measuring the main
parameters that permit to supervise the
state of the whole system.
Fig. 2: Curves & additional help text display example
Fig. 3: Operational flowchat
Fig. 4: Warnings & messages automatically displayed
Warning messages can be obtained informing
of the constraints that must be matched and the
procedure to follow, providing additional
instructions and diagrams to assist the operator.