Maintaining nuclear safety as a priority
Maintaining nuclear safety is the cornerstone of our operations, it governs everything we do.
Our operations are governed by a series of safety cases, essentially the rulebooks for how we operate all aspects of our power stations and are reviewed by our independent regulator the Office for Nuclear Regulation (ONR). We work closely with the ONR and welcome the strict regulation that they provide. It underlines our joint determination to ensure nuclear safety.
We work within very large safety margins that are approved by the regulator. They do not define a boundary between safe and unsafe and there is a massive margin before the plant would be considered to create an unacceptable risk.
We would never allow our plants to reach this point and would close them down long before we reached a state that was anywhere near unsafe. We are required to demonstrate operational limits which ensure we operate with large safety margins. As our knowledge improves, then our process requires us to agree changes to the operational limits with the external regulator.
For graphite cracking, we have been able to show these safety margins and we can show that, even in the unlikely event of a major earthquake, there is no significant impact on the core in terms of distortion, and would not present a challenge to the operation of the control rods or other shut-down systems. These are based on our understanding of graphite behaviour, and extensive research and development programme.
In addition to this, we have invested in modifications to provide further margins to safety. In extreme and unprecedented circumstances, such as a seismic event, each reactor has several super-articulated control rods which would be inserted into the reactors to safely shut it down.
In the highly unlikely event that the number of control rods inserted into the reactor was unable to stop the nuclear reaction, our stations are equipped with plant that would quickly inject nitrogen gas into the core and stop the nuclear reaction.