HL Deb 05 February 1980 vol 404 cc1330-2WA
Lord HYLTON

asked Her Majesty's Government:

Whether the earthquake in December caused any leakage of radiation from nuclear establishments or aggravated the existing leaks at Windscale.

To what extent, if at all, the design of existing nuclear reactors (including power stations and experimental reactors) is intended to provide protection against damage by earthquakes.

Whether the provision of protection from earthquake damage is feasible in the case of existing reactors, and if so at what order of cost.

What anti-earthquake devices are included in the specifications of the nuclear power stations under construction at Torness and Heysham; what is the estimated cost of the devices; and why were they included, if earlier nuclear reactors were not thought to need such protection.

Whether the likely amount of warning of an earthquake shock gives sufficient time for any safety procedures to be put into action at a nuclear reactor.

The EARL of GOWRIE

Following the earthquake on 26th December there was no evidence of damage to any nuclear installation in this country nor of any effect on the leak of radioactivity from the B 38 silo at Windscale. Well-built structures such as those of nuclear installations are able to withstand safety intensities at the levels of any earthquakes they are likely to experience in the United Kingdom. Because the risks of significant damage are small, design requirements for existing plant in the United Kingdom did not include criteria specifically for protection against earthquakes. Nevertheless, as part of the process of progressively improving already high safety standards, new nuclear installations in this country, including Torness and Heysham stage II, will be built to meet specific safety criteria which set the appropriate level of protection against earthquakes of higher intensity than those ever recorded in the United Kingdom, or regions elsewhere of similar geological stability. It is not possible to identify the precise costs of incorporating these design features, but they are low in relation to the total cost of constructing the stations in question.

Taking account of the general robustness of existing installations, Her Majesty's Nuclear Installations Inspectorate do not consider it necessary to require the "back- fitting" of these design features to existing plant.

Little warning is likely to be received of the onset of an earthquake. However, the inherent protection provided by the robustness of construction of all nuclear plant means that prior shutdown of a reactor is not considered necessary.