HSE AGREES MOVE TO REDUCE SELLAFIELD DISCHARGES

HSE press release: E100:03 - 17 June 2003

The Health and Safety Executive has given permission to British Nuclear Fuels plc (BNFL) to re-route the future production of a key radioactive liquid process stream, Medium Active Concentrate (MAC), at Sellafield. In the long term this will significantly reduce radioactive discharges into the environment.

The modification to re-route new MAC was a key part of the Environment Agency's decision on the future regulation of technetium-99 discharges from Sellafield. The Agency's decision acknowledged the need for the proposed rerouting to be subject to HSE permission.

Currently, arisings of MAC from Magnox reprocessing are sent to the Enhanced Actinide Removal Plant (EARP), where the bulk of the radioactivity is removed, before discharge to the Irish Sea.

The intended modifications will route future MAC to storage in the highly active storage tanks and subsequently to vitrification. BNFL has had to demonstrate to HSE that a modification to the process and operations can be done safely and will have no detrimental effects on either the high level waste storage or the vitrification plants.

The outcome of this decision will be to significantly reduce the level of discharges of radioactive Technetium-99 (which EARP is unable to remove) and other radioactivity from future MAC arisings into the Irish Sea.

The modification will allow the volume of MAC stored in tanks on site to be reduced to minimum operational levels. Having received this permission, BNFL can now start the process of diverting the MAC to Highly Active Storage.

Notes for Editors

1. The consent to MAC diversion was issued by the HSE's Nuclear Installations Inspectorate, as part of its normal regulatory process under the nuclear site licence.

2. Technetium-99 (99Tc) is a fission product produced in the use of nuclear fuel. In the reprocessing of Magnox fuel about half of the 99Tc enters the highly active process stream and the other half goes into the process streams for evaporation to make Medium Active Concentrate (MAC). The MAC is currently stored in tanks for 3 to 5 years (to allow decay of short lived radio-nuclides) before being treated by the EARP process, which removes actinide species, but not the 99Tc. Since the commissioning of EARP, 99Tc in previously stored MAC has been discharged to sea resulting in a return to the levels of 99Tc in the marine environment from which it had fallen in the early 1990s.

3. In September 2001 the Environment Agency published its proposed decision that the future regulation of 99Tc discharges from Sellafield would best be implemented by its preferred option to divert future arisings of MAC, which contains the 99Tc, to the high active waste treatment/storage plants and to continue development of technology to deal with the MAC which is currently being stored on the Sellafield site. EA's decision acknowledged the need for the proposed rerouting to be subject to HSE permission, carried out safely and in a manner that would not be detrimental to the safe storage and processing of the high level waste into a disposable vitrified form. In December 2002, the Environment Minister endorsed the decision document.

4. In December 2002 BNFL prepared modification proposals to describe, justify and control the process and operational changes needed to produce MAC in a form, known as salt free MAC (SFMAC), that would be acceptable to the high level waste and vitrification plants. HSE's NII considered that BNFL's proposals were of sufficient importance that HSE issued a specification under the nuclear site licence requiring BNFL gain the Executive's consent before: (i) making the changes to enable the production of SFMAC and (ii) diverting the SFMAC to the highly active storage tanks and subsequent vitrification.

5. At both stages NII has assessed BNFL's proposals to confirm that it is safe to produce salt-free MAC and that it is safe to divert the SFMAC to the highly active storage tanks for subsequent vitrification. As part of the regulatory process NII has consulted with EA. HSE granted the first consent on 30 January 2003 to give BNFL permission to start the production of SFMAC. Following successful demonstration that that SFMAC is suitable and safe for diverting to the highly active storage tanks and subsequent vitrification HSE has granted the second consent to allow MAC diversion to go ahead.

6. The backlog of MAC (some ~1850m3) is chemically unsuitable for vitrification and will be treated in EARP before discharge to sea.

Press enquiries

All enquiries from journalists should be directed to the HSE Press Office