Report on radioactive discharges and environmental monitoring at nuclear sites during 1988

The details of radioactive discharges from and environmental monitoring in the vicinity of nuclear sites in the Untied Kingdom are presented. The highest predicted dose, resulting from a station's liquid discharges, was to a small group of fish eaters at Trawsfynydd, and is estimated at 120μSv. This is lower than in previous years. Based on the measurements made in marine samples, the dose to a group of fish and shellfish eaters at Heysham is estimated at 160μSv and the external dose to a group living and working on the tidal mud-flats of the nearby Lune Estuary, 120μSv. Only a small fraction of these doses can be attributed to discharges from Heysham. Discharges of Ar-41 are highest from stations with shield cooling air systems. In 1988, the maximum predicted dose associated with Ar-41 releases occurred at Sizewell and was calculated to be 60μSv. At some stations there is a contribution from direct radiation from the plant at locations in close proximity to the boundary fence. In 1988, the estimated highest dose from this source was 0.7mSv and occurs at Bradwell. Radiation doses to members of the public, resulting from discharges and from direct radiation were, in all cases, less than the principal limit of 1mSv/year recommended by ICRP. (author)