§ Mr. Costainasked the Secretary of State for Energy if he will make an early statement on the reasons for closing down Dungeness A reactor; and if he is satisfied that there is no health risk to employees at the nuclear power station and those living in close proximity thereto.
§ Mr. Norman LamontI am advised by the chairman of the Health and Safety Commission that number 2 reactor at Dungeness was shut down in late August 1978 for its routine statutory inspection and overhaul and has not yet been returned to power. Number 1 reactor started its programmed statutory inspection and overhaul in April this year and accordingly both reactors are now shut down.
The inspection of number 2 reactor was planned to take about three months, but was extended to enable repairs to be carried out to a gas circulator drive coupling and to weld defects found in the gas circuits and attachments. The major defect found in the gas circuits was cracks in a weld in a compensating bellows in the branch duct of a main gas circulator and the investigative work and repairs to this weld were the principal cause of 20W the extended shutdown. After completing the repair to the defective weld final nondestructive testing checks on the bellows unit revealed some surface defects in the weld between the bottom of the bellows and a flange forging. These defects were also found in the equivalent units in the other gas circuits. No similar defects have been found in any of the other bellows units at Dungeness or in bellows units at other nuclear power stations.
In common with other industrial activities the operation of nuclear power stations cannot be entirely free from risk but the precautions taken in the design and operation of these stations reduce the risk to a very low level. The Health and Safety Executive would not grant a nuclear site licence or allow continued operation unless it was satisfied with the standards achieved. The weld defects at Dungeness A have not introduced any additional risk to the health and safety of employees or the public but the Nuclear Installations Inspectorate has requested further supporting information on the nature of the surface defects in the welds. This information is required to gain assurance on the continued integrity of the gas circuits and the reactors will not be permitted to return to power until it has been received and assessed.