Nuclear Reactor Safety

There are many safety features and controls in place designed to minimise the risk of harm to humans and the surrounding environment.

Fuel Used

Using solids rather than liquids avoids the danger of leaks or spillages. They are inserted and removed from the reactor by remote controlled handling devices.

Shielding

The reactor core (containing the fuel, moderator and control rods) is made from steel and designed to withstand high temperatures and pressures.

The core itself is inside a thick, leak proof concrete box which absorbs escaping neutrons and gamma radiation.

Around the concrete box is a safety area, not to be entered by humans.

Emergency Shut-down

There are several systems in place to make it impossible for a nuclear disaster to take place:

If the reactor needs stopping immediately the control rods are inserted fully into the core, they absorb any neutrons present and stop any further reactions from happening.

Some reactors have a secondary set of control rods held up by an electromagnet, so if a power cut happens the control rods fall into the core.

If there is a loss of coolant and the temperature of the core rises beyond the safe working limits an emergency cooling system floods the core (with nitrogen gas or water) to cool it and absorb any spare neutrons.