Progress in the reduction of liquid radioactive discharges from the Sellafield site Ko (223)

Prior to reprocessing, fuel is stored in ponds. Storage and the subsequent reprocessing result in the generation of radioactive liquid effluents. The highly active liquors are stored in stainless steel tanks and will be converted into glass for long term storage and disposal. The medium active liquors are evaporated and are stored to permit the short lived isotopes to decay. These concentrates used to be discharged to sea, after storage, but since the early 1980's no such discharges have been made. Low active effluents are discharged to sea well within authorized limits. For many years BNFL have adopted a policy of reducing the levels of activity discharged to sea and significant improvements have already been made. In 1985 the Site Ion Exchange Effluent Plant (SIXEP) was brought into operation to treat the purge water from the ponds. The evaporation and storage of medium active liquors from the solvent extraction process has also played a major part in reducing discharges. The commissioning in 1985 of the Salt Evaporator has allowed the sodium salt bearing liquors from solvent washing operations to be stored thus extending the reductions made by storing medium active concentrate. The storage of medium active and salt concentrates amounting to about 700 m3/y from magnox reprocessing is only an interim measure and further treatment is required. Additionally, one fifth of the low active effluent, not treated by SIXEP amounting to about 250m3 per day accounts for the majority of the activity currently discharged to sea. Treatment of this effluent would substantially reduce the total discharge of activity to sea