HC Deb 20 February 1980 vol 979 cc219-21W
Mr. Emery

asked the Secretary of State for Energy what is the ratio of radioactive emission from a typical or average (a) nuclear power station, (b) coal-fired station and (c) an ash disposal site, compared with the natural emission of a green field site.

Mr. Norman Lamont

[pursuant to his reply, 11 February 1980, c. 427]: The following further information: A distinction should be made between the total amount of radioactive material emitted from the sources mentioned and the resulting radiation exposure to the public. Any comparison of emissions needs to take into account the widely different characteristics of the radioactive materials involved, the dilution of power station emissions by atmospheric dispersion, and the contribution of natural background, including cosmic radiation, to United Kingdom radiation levels.

I am advised by the National Radiological Protection Board that present evidence relating to the most exposed persons living near power stations indicates that in general similar radiation exposures are received form effluent emissions from both modern coal-fired and existing nuclear stations, but that these exposures are low—representing an addition of only a few percentage points to the exposure arising from the natural background.

CEGB further estimates that the average radiation exposure experienced by an average member of the population arising from the natural background, compared with the additional radiation exposure attributable to power stations and waste ash sites is as follows:—

Green field site (United Kingdom typical 1.0
Green field site (United Kingdom Maximum 1.3
Additional Exposure from a nominal 1000 MW United Kingdom Nuclear Power Station 0.000015
Additional Exposure from a nominal 1000 MW United Kingdom Nuclear Power Station including reprocessing of the irradiated fuel 0.0006
Additional Exposure from a nominal modern 1000 MW United Kingdom Coal fired Power Station 0.00015

Exposures at waste ash sites are similar to those at greenfield sites. Thus, the additional exposure to an average member of the population from power stations is negligible by comparison with the range of exposure from the natural background.

I am advised that the CEGB estimates the annual average of naturally occurring emissions from a typical United Kingdom green field site 1 km square to be about 1300 curies of radioactivity. By comparison, the annual emissions from a modern 100.MW United Kingdom coal-fired station are about 0.001 of this, while emissions from one of the existing United Kingdom nuclear gas-cooled stations are up to some 100 times greater, depending on reactor design. Emissions from a waste ash site are similar to those from a green field site.