Power station event tree analysis

Assessing the probability of a particular situation occurring in a power station

In this lesson students will use event tree analysis to roleplay an exercise where they quantify the risk of safety systems failing in a power station.

This is one of a set of resources developed to aid the class teaching of the secondary national curriculum, particularly KS3. It has been designed to support the delivery of key topics within mathematics.

In this activity, students will roleplay the following scenario:

‘A power station experiences a loss of coolant to its reactor about once per year. To prevent a dangerous explosion, a set of controls are in place. Firstly, an alarm which alerts the operator, this works on 99% of occasions. If this does fail various other systems will become operational to monitor the issue and prevent disaster.’

Using the examples in our Power station event analysis handout and Event analysis presentation, students will learn how event tree analysis can be used to model the probability of the risk of safety systems failing. Students can also use our Event analysis simulator tree spreadsheet to run simulations to check their workings.

Download our activity overview for a detailed lesson plan (including answers) for teaching students about event tree analysis.

The engineering context
Event trees allow engineers to visualise the chain of events that could lead to system failures. Analysing the probabilities of these events helps them understand the likelihood of various outcomes as part of their efforts to design measures that can help to mitigate risks.

Suggested learning outcomes
In this lesson, students will learn about frequency trees, probability, and relative frequency.

Download our activity sheet and other teaching resources
The activity sheet includes teachers’ notes, useful web links, and links (where appropriate) to the national curriculum in each of the four devolved nations; England, Northern Ireland, Scotland and Wales.

All activity sheets and supporting resources are free to download (including the video), and all the documents are fully editable, so you can tailor them to your class’s and your schools’ needs.

You can download our classroom lesson plan for free!

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