Mr. Alan WilliamsTo ask the Secretary of State for Defence on what basis the 550-metre safety zone was deemed to be appropriate in relation to the berthing of nuclear-powered submarines; and if he will make a statement.
§ Mr. Archie HamiltonThe 550-metre zone is the distance at which automatic countermeasures should take place in the event of a submarine nuclear reactor accident. It derives from predictions of the probability and consequences of accidents which are based on our best and most up-to-date technical advice, and are carried out in accordance with the recommendations laid down by the International Commission for Radiological Protection. The 550-metre zone would be sufficient for the vast majority of potential reactor accidents, most of which would not in fact result in any radiological hazard to the public. We also plan, in conjunction with local authorities, against the even more remote possibility of an accident which would require countermeasures outside this area; in this event countermeasures would be advised on the basis of monitoring information.