HC Deb 31 July 1980 vol 989 cc803-4W
Mr. D. E. Thomas

asked the Secretary of State for Energy whether the Central Electricity Generating Board informed his Department of a nuclear incident at Trawsfynydd power station during the last 10 days; if he will undertake a full departmental inquiry into all circumstances surrounding this incident; and if he will make a statement.

Mr. Norman Lamont

[pursuant to his reply, 10 July 1980, c. 305–6]: The Nuclear Installations Inspectorate has informed me that the safety checks being performed on the No. 1 reactor at Trawsfynydd nuclear power station have indicated that the amount of moisture in the reactor is greater than at first thought. Moisture has been found in some control rod drive motors and position indicators. These are being inspected and refurbished if necessary; the shutdown of the reactor will consequently be extended.

The drying out of the reactor involves the controlled venting to the atmosphere of carbon dioxide gas containing small quantities of radioactivity. Some further venting may be necessary. The NII informs me that environmental monitoring has detected low levels of activity on grass and some slight activity in milk samples. I am advised that the Radiochemical Inspectorate and the food science division of MAFF, who jointly assist the Secretary of State for Wales in his responsibilities under the Radioactive Substances Act, consider that the levels of activity detected in these milk samples are far below the level which would correspond to the dose limit recommended by the ICRP.

The safety checks on the reactor and the environmental monitoring are continuing. The reactor will not be started up until the checks have been completed to

the satisfaction of the CEGB and the NII. The incident will be included in the appropriate quarterly report of the Health and Safety Executive.