Expert Systems

Discussion Questions

1. What features are essential in an expert system responsible for the safety of something as potentially dangerous as a nuclear power plant?

In the nuclear power industry, a popular assessment technique used is probabilistic safety analysis (PSA), which enables engineers to assess the probability and consequences of potential plant safety-related problems. PSA creates and interprets fault-tree diagrams, a graphical model illustrating the pathways within a system with logical constructs such as AND and OR. Following the pathways through the system can identify weaknesses and points of failure.

2. What characteristics of the process of probabilistic safety analysis do you think led TEPCO to believe it that could be automated in an expert system?

A TEPCO safety engineer might take days or even weeks to work through a fault-tree analysis. This tedious process struck TEPCO management as one that was idea for automation. Gensym Corporation worked together with Tokyo Electric Power Corporation (TEPCO) to deploy a system they named FT-Free which automatically creates PSA fault-tree models that represent potential failure modes for critical plant processes. From a model, engineers apply FT-Free's built in expertise to quickly assess the risks of various types of problems that can adversely impact the plant's reliability and safety. Through this assessment, engineers drive critical decisions about a plant's process configuration and its operational safety procedures. The system can do in minutes what used to take days or weeks. Not only is it a huge time saver, but it also provides consistency that was previously lacking. The new system provides unique abilities to intuitively capture process engineering knowledge using such techniques as connectable object models and rule-based logic.

Critical Thinking Questions

3. What other industries would benefit from a product such FT-Free? Why?

TEPCO Systems has successfully deployed FT-Free within a TEPCO nuclear power plant facility, is expanding its use within TEPCO, and is now marketing it to the electric utility industry.

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