Sizewell B has submitted the results of its safety review to the UK’s independent nuclear safety regulator (ONR) justifying that it is safe to continue operating following the defects found in the Belgian pressurised water reactor Doel 3.
In June 2012 routine safety inspections of Doel 3 indentified a large number of small defects in the reactor pressure vessel. As a precautionary measure a safety review was instigated at Sizewell B, the only pressurised water reactor in the UK.
The robust safety review of Sizewell B confirmed that –
- Advanced steel making processes have meant that no flaws of the kind seen at Doel 3 were present at the time of manufacture
- Ultrasonic tests which would have detected defects in the pressure vessel similar to those found at Doel 3 were conducted and independently validated following manufacture, during pre-service inspections and through routine in-service inspections at the station
- The detailed review of the Sizewell B vessel lifetime records confirm that the Reactor Pressure Vessel was manufactured and inspected to a very high quality. There is therefore no evidence from the Doel 3 operational experience that changes the risk analysis already presented in the Sizewell B safety case.
Furthermore, the twenty year inspection of the Reactor Pressure Vessel at Sizewell B which is due to take place in Spring 2016, will include re-inspection of the main welds in the Reactor Pressure Vessel and some sections of forging material. These inspections will use the same techniques as those deployed at the ten year inspection in 2005 and which have been demonstrated to be sufficiently sensitive.