Office for Nuclear Regulation

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Sizewell C - Control Safety Systems

Information released

Can you please explain how the control system of Sizewell C will be protected from intruders? The information should include:

I would like to understand the effects of about 9 GW heat being put into the sea from Sizewells B & C, especially including the effects of the underwater barrier a short distance off the coast. 

No specific information has been submitted to ONR regarding control systems for any future nuclear reactor at Sizewell C. However, ONR will assess any future submission, prior to build, to ensure computerised systems (including safety and control systems) are adequately protected from physical and electronic intrusion.  

To answer your questions individually:

It is important to note that all current and proposed nuclear reactors in the UK have non-computerised backup safety systems in addition to the computerised safety systems. These non-computerised systems are, by design, not susceptible to computer based threats.

ONR do not hold any information on the Sizewell C site specific issue relating to the impact upon flora and fauna of heat ejected from the seawater cooling system. However you may wish to re-direct your enquiry to the Environment Agency as they may hold this information

Exemptions applied


PIT (Public Interest Test) if applicable

Not applicable.