CHANGES IN LIQUID RADIOACTIVE WASTE DISCHARGES FROM SELLAFIELD TO THE IRISH SEA: MONITORING OF THE ENVIRONMENTAL CONSEQUENCES AND RADIOLOGICAL IMPLICATIONS

摘要

In January 1994, British Nuclear Fuels plc (BNFL) were granted revised authorisations for disposal of radioactive wastes from their Sellafield site in Cumbria, UK, including the discharge of liquid effluent to the Irish Sea. The revisions took account of a continuing Government commitment to review authorisations regularly, as well as of new Sellafield plants and changes to existing operations. The new plants of prime importance were the Thermal Oxide Reprocessing Plant (THORP) for the reprocessing of oxide fuels, and the Enhanced Actinide Removal Plant (EARP) for improved treatment mainly of waste streams from the older, Magnox, plant. Many of the radionuclide discharge limits reduced significantly, notably for Cs-137, Ru-106 and the actinides, to reflect operation of EARP. Increases in limits, of relatively low radiological significance, were granted for tritium and I-129 which would be produced by operation of THORP. An increase for C-14 covered diversion to sea of Magnox gaseous scrubber liquors, so as to reduce the overall radiological impact of these waste streams. Increases for Sr-90 and especially Tc-99 were to allow discharge, after phased processing through EARP, of liquors which have been stored on site for an optimised period.