Annual report on radioactive discharges and monitoring of the environment 1979

This report gives information on radioactive discharges through authorised outlets and on environmental monitoring, for all of the British Nuclear Fuel Company's Works and Sites ie the Windscale and Calder Works and the Drigg Storage and Disposal site; Chapelcross Works; Springfields Works and the Ulnes Walton Disposal Site; and Capenhurst Works. Where a site also encompasses laboratories of the United Kingdom Atomic Energy Authority (UKAEA) reference is made to the significance of the discharges from the latter. The report includes assessment of maximum radiological exposures to individual members of the public expressed in terms of limits based on the recommendations of the International Commission on Radiological Protection (ICRP) and in accordance with advice given by the National Radiological Protection Board (NRPB) on the application of the Commission's recommendations in the UK. It is recognised that certain consequences of exposure are believed not to occur unless a threshold dose to a particular part of the body is exceeded and that other possible consequences can be evaluated by computing an effective dose equivalent. In both cases limits are stated, the latter being 5 millisievert (500 millirem) per annum, together with the comment that it would be prudent to restrict actual continuous exposure over a whole lifetime to an average of 1 millisievert (100 millirem) per annum. The assessments are based on data recommended by ICRP. Where these data are not yet available the assessments are based on data published by NRPB as interim recommendations. The percentage of the effective dose equivalent limit is quoted together with the individual contributions to it. Where other limits, which are 'threshold' in nature and cannot be summed, are apparently more restrictive a textual comment is made. (author)