Water and energy for everyone · Volume two
N03 Protections that work together
Look, connect the ideas and tell the story
- Barriers
- Checks
- People with the right skills
Words and symbols to help us tell the story. Sizes and distances are not to scale.
Keeping the materials safely contained needs several barriers. We can imagine them as shells, one inside another. Each barrier in a power station has a job. There are also instruments, checks and people with the right skills. Experts check that the protections can work together. The child looks at the model with an adult and asks questions.
Why do experts check more than one protection?
For the accompanying adult
The R12 version distinguishes fuel, cladding, the circuit and containment, alongside sensors, shutdown, cooling, operators and emergency plans. The shell model is a metaphor, not a construction drawing. Defence in depth includes prevention and mitigation. Independence, faults shared by several systems and external conditions must be analysed: adding barriers does not prove safety on its own.
Sources for further reading R12 F3 F4 · Final section of the book