§ Mr. Churchillasked the Secretary of State for Energy if he will make a statement in regard to the accident which took place on 29th June 1977 at the Hinkley B advanced gas-cooled reactor; what steps he took to bring this accident to the notice of Parliament; and if he will give an assurance that the two new advanced gas-cooled reactors which he announced last week will incorporate a more effective and reliable emergency cooling system.
§ Mr. EadieThe incident referred to occurred when an 18-inch pipe supplying sea water to the reactor auxiliaries cooling system at Hinkley Point B Station fractured. This was reported in the second quarterly statement on incidents at nuclear installations which was published on 31st August 1977 under the arrangements which my right hon. Friend announced to the House on 2nd February 1977. Copies of the quarterly statements are placed in the Library of the House.
I am advised that the fracture led to extensive flooding of one half of the sea water pump house and loss of the reactor auxiliaries cooling system sea water supply. Station staff were unable to restore the supply from the other half of the pump house because of a failure 295W in a sectionalising valve in the sea water system, and an alternative cooling water supply was provided within three hours when fire hose connections were made to a town's water supply from a 1 million-gallon storage tank on the site. At the time of the incident only one reactor was operating and this was shut down when the fracture was discovered.
In the period that the cooling water supply to the reactor auxiliaries cooling system was interrupted, reactor cooling was not affected, the cooling gas temperature was reduced to the normal shutdown value and there was no risk of a radioactive release. The temperature of the gas circulators and concrete pressure vessel, which are indirectly cooled by the sea water, did not rise to unacceptable levels. Although there was extensive damage to electrical equipment in the flooded half of the pump house which took 14 days to clean up and reinstate there was no damage to the reactor or turbo-generator plant.
Connections have since been provided to the coolers in the reactor auxiliaries cooling system at Hinkley Point B to facilitate temporary connections to the town's water storage supply on the site. All later designs of AGR have been provided with permanent connections to a backup cooling water supply. This feature will be incorporated in any future AGR designs.