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Dounreay's Discharge Permissions

In July 1999 the Scottish Environment Protection Agency's recommended new radioactive discharge authorisations for Dounreay were approved by the Scottish Government - marking the end of a six year saga: it was 1993 when Dounreay first applied to SEPA's predecessor, HM Inspectorate of Pollution, for new discharge permissions.

At the time Dounreay planned for a huge expansion in reprocessing work, especially contracts for reprocessing weapons-grade highly-enriched uranium (HEU) from research reactors. However this was not to be and Dounreay's hopes crumbled: environmental concerns, opposition from the US Administration and problems on site ended hopes for the HEU work. In addition both reprocessing plants were closed, one for lack of work the other after a major leak; the government announced an end to commercial reprocessing at Dounreay; waste and contamination were found around the site and outside; fishing was banned off Dounreay when radioactive particles were found on the seabed and regulators condemned safety and management at the plant and demanded over 140 improvements. (See the Latest News Pages for more information).

In July 1999 Dounreay's future consists mainly of clearing up past problems and decommissioning the two fast reactors and other buildings. The HEU reprocessing plant is being decommissioned and a government decision on whether to spend at least £40 million repairing the mixed oxide plant is still awaited. The remaining waste spent fuel on site will either be reprocessed at Dounreay, or at Sellafield or placed in long-term storage. If it is to be reprocessed at Dounreay further approval from SEPA will be required, as explained in the official Summary of Decision which is reprinted below from the SEPA Web Pages. See our other features or Latest News Pages for more background information.

Summary of the Decision by SEPA on the Application from UKAEA to Dispose of Radioactive Wastes from Dounreay, Caithness, Scotland

Authorisation

In his response the Secretary of State for Scotland noted that the authorisations had been significantly amended from those which were originally consulted upon and concluded that it was in the wider public interest that SEPA should be invited (August 1997) to initiate a fresh consultation process based upon the revised authorisations it was minded to grant. On 9 September 1997 SEPA decided to put in hand this further consultation which took place between 17 November 1997 and 23 February 1998.

The revised authorisations resulting from this process have again been forwarded (October 1998) to the Secretary of State for Scotland. A "near final draft" decision document was sent (November 1998) to The Scottish Office at their request. SEPA considers that the revised authorisations that SEPA is minded to grant are not significantly different from those which were consulted upon.

SEPA's Assessment of the Environmental Effects

SEPA is also satisfied on the basis of current studies that the risk from the continuing disposal of solid low level radioactive waste to the small remaining available space in the shallow land burial facility at Dounreay is below the risk target of 10^-6 per year provided the total inventory of all alpha emitting radionuclides is restricted to 2 terabecquerels, and for all other radionuclides, restricted to 60 terabecquerels. SEPA is however less satisfied on aspects of sustainable development, particularly with regard to coastal erosion. SEPA will therefore require UKAEA to investigate further these aspects of their low level waste disposal practice, and will not at this juncture authorise disposals to any extension to the current disposal facility.

SUMMARY OF THE MAIN CHANGES MADE TO THE CERTIFICATES OF AUTHORISATION WHICH WERE SUBJECT TO SECOND PUBLIC CONSULTATION.

Changes made in order to provide more effective controlA further practice has been added to the authorisation, namely the treatment of either Vulcan waste or waste from other tenants on the Dounreay site. This is to allow for example, UKAEA to supercompact low level waste from either Vulcan or tenants on the site. In order to provide further regulatory control over the decommissioning activity at both DFR and PFR a small alpha discharge limit has been added to the gaseous discharge authorisation. This addition is a result of SEPA becoming aware that the sodium and sodium/potassium coolant of both PFR and DFR is contaminated with trace quantities of alpha emitting radionuclides (principally plutonium). A limit of 10 MBq and 6 MBq total alpha have been included for DFR and PFR respectively. The authorised limit for gaseous discharges of krypton 85 from the East Minor sources has been reduced to the level applied for by UKAEA in their 1993 application. This corrects a provision which would have provided for the operation of a new small scale reprocessing facility. This was not SEPA's intention, and such a facility has not been considered by SEPA nor subject to public consultation. The abatement of liquid discharges by the addition of an ultra filtration process or an equivalent process as agreed in writing with SEPA to the low level liquid waste stream resulting from the settling operations forming part of the ammonium diuranate (ADU) floc process in building D1208 prior to its disposal from the premises has been made a condition for recommencing reprocessing. The previously proposed date for this has been removed. SEPA will not authorise the disposal of solid low level radioactive waste to UKAEA's proposed extension to the low level waste pits (pit 6E) unless and until UKAEA can make a satisfactory post closure safety case, subject to due consideration by SEPA. This case will need to be robust and should be able to demonstrate that coastal erosion will not result in the waste being released directly into the environment over foreseeable timescales. Until such a post closure safety case has been made SEPA's authorisation (via the Technical Implementation Documents) will not include disposal to pit 6E. Changes made in order to aid with the transparency of the application and authorisationSEPA has linked the operations called "practices", from which radioactive waste may be disposed to the individual plants where the practice is carried out. This should greatly increase the transparency of Dounreay's undertakings and should overcome the question of what reprocessing capabilities exist at Dounreay. This is agreed between SEPA and UKAEA and set out in the authorisations and the technical implementation documents (TIDs). Radioactive waste arising from reprocessing operations is limited to that arising from reprocessing of irradiated fuel subject to commercial contracts signed prior to 5 June 1998, and UKAEA's own liabilities. Only the quantities listed in the authorisations may be reprocessed. With the above requirement in place SEPA has now removed its proposed "return of waste within ten years" clause. A number of changes have been made to the definition section. Waste from decommissioning activities is limited to planned and documented decommissioning work as required under the Dounreay site license issued under the Nuclear Installations Act 1965. The practice of reprocessing (irradiated fuel) has been explicitly defined as distinct from processing (essentially unirradiated fuel) to reflect UKAEA's own definitions as stated to SEPA. This should clarify any ambiguity regarding the practices undertaken at Dounreay. SEPA has clarified its requirements for a Best Practicable Environmental Option (BPEO) study to include a specific study on the treatment of Prototype fast reactor fuel. The timescale for this study is such that it will report before any reprocessing operations recommence at Dounreay. SEPA believes that such a study may well provide useful information to those responsible in Government for the decision to replace the dissolver in D1206, and SEPA would at that juncture consider the need to amend the Dounreay authorisations.