Environment Agency seeks opinions on radioactive discharge

The Environment Agency is seeking comments on its proposal to oblige British Nuclear Fuels (BNFL) to considerably reduce the discharge of radioactive technetium-99 from its plant at Sellafield into the Irish Sea by 2006.

Technetium-99 (Tc-99), with a half-life of 213,000 years, is produced as a result of the fission of uranium and plutonium in a nuclear reactor, and cannot currently be removed from effluent by the Enhanced Actinide Removal Plant (EARP), which removes other radionuclides such as plutonium and americium. Discharges of Tc-99 have increased recently as a result of the treatment of the historic backlog of waste that is stored on site at Sellafield, though, according to BNFL, the amount being discharged is still radiologically insignificant.

The Environment Agency has considered a number of options for the plant, which is currently discharging up to 90 Terabecquerels (TBq) of Tc-99 per year, taking into consideration environmental impact, technical feasibility, waste management aspects, health and safety, costs, and operational and socio-economic criteria. The options that have been studied by the Agency range from reducing the discharge limit to 10 TBq of Tc-99 per year in 2001, through to retaining the current limit of 90 TBq per year.

The Environment Agency proposes that:

  • Tc-99 in Medium Active Concentrate (MAC) arising from Magnox reprocessing is diverted for vitrification instead of being diverted into the sea by 2003, provided there is a satisfactory outcome to current development work, and subject to approval by the Health and Safety Executive (HSE);
  • should the diversion of MAC be feasible, the process should be implemented by 2003, retaining the current limit of 90 TBq per year until 2006 to allow the treatment in the EARP of all the MAC currently being stored;
  • a condition should be put in place requiring BNFL to implement a trial of chemical treatment using tetraphenylphosphonium bromide (TPP) in the EARP as soon as possible, which would produce a solid waste for encapsulation in cement;
  • if the TPP treatment process is feasible on a large scale, the Agency will require the full implementation of this technique, allowing a substantial reduction in the discharge limit before 2006;
  • a reduction in the discharge limit to 10 TBq per year should be in place from 2006, with a reduction in the shorter timescale if the TPP process is feasible;
  • BNFL should be required to report quarterly on progress towards reducing Tc-99 discharges.

    Comments on the consultation document should be made by 5 March 2001, and can be made via the Agency’s website: www.environment-agency.gov.uk/consultations. Alternatively, copies of the document can be obtained from public registers at all offices of the Environment Agency, at the offices of local authorities in Cumbria, at the Lea offices of Lancashire County Council, at the principal offices of all local authorities bordering the Irish Sea in England, Wales, Scotland and Northern Ireland, or from the Environment Agency on 01768 866 666.

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