ENVIRONMENTAL MONITORING ASSOCIATED WITH THE DISCHARGE OF LOW ACTIVITY RADIOACTIVE WASTE FROM WINDSCALE WORKS TO THE IRISH SEA.

Abstract

Since 1952, low activity radioactive waste has been discharged by pipeline from Windscale Works to the Irish Sea off Sellafield. Environmental monitoring studies have been carried out throughout this period in order to assess the resultant radiation dose to man, and hence to estimate the discharge rate which would correspond to the maximum permissible radiation doses recommended by the International Commission on Radiological Protection. These studies have been concerned principally with those materials most likely to contribute substantially to the dose to man, and they have been supplemented by more widespread marine surveys and by laboratory studies aimed at gaining information about the movement and behaviour of radioactive nuclides in the marine environment. It has been concluded from these studies that the rate of discharge from Windscale Works to the Irish Sea cannot be permitted to exceed about 100,000 c/month of mixed fission products, and that specific restrictions are needed on a number of individual nuclides, namely, strontium-90 (about 2000 c/month), ruthenium-106 (about 5000 c/month) and cerium-144 (about 20,000 c/month). The present discharge rates are about 4000 c/month of mixed fission products, of which about half is ruthenium-106 and about 2 per cent strontium-90.