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10 June 04
UKAEA DOUNREAY CONSULTS ON CHANGE
IN REFERENCE STRATEGY FOR FAST REACTOR WASTE
UKAEA Dounreay today launches the consultation phase about its change in reference strategy for conditioning liquid wastes that are a legacy of reprocessing fast reactor fuel at Dounreay.
A newsletter being issued to over 800 organisations and individuals explains the background to the issue and sets out the process for seeking their views.
Fuel irradiated in the UK’s Prototype Fast Reactor was reprocessed at Dounreay until 1996 to separate the waste, or fission products, from the re-usable plutonium and uranium. The waste was extracted in the form of an acidic liquor, or raffinate, and approximately 200m3 accumulated in underground tanks, where it continues to be stored safely and securely today.
Historically, the waste required artificial cooling, meaning it was classified as high-level waste in accordance with national and international definitions, and UKAEA’s reference strategy was to vitrify it as blocks of glass. The waste has decayed since reprocessing ceased in 1996 and now no longer requires artificial cooling. This means it can be reclassified as intermediate-level waste and conditioned in cement on an earlier timescale.
UKAEA Dounreay has now changed its reference strategy for managing this waste from vitrification to cementation. This would involve the construction of a new plant to condition this waste in drums of cement to make it safe for long-term storage or disposal as intermediate-level waste.
The consultation phase of this change in reference strategy is divided into two stages:
Norman Harrison, director of UKAEA Dounreay, said: "The raffinate from the reprocessing of fast reactor fuel accounts for nearly half of all the radioactivity in our waste inventory at Dounreay, so its conversion to a solid form that can be stored safely and securely in the longer term is one of our highest priorities.
"The knowledge that the raffinate
can be cemented on an earlier timescale than vitrification, using tried
and trusted technology, is potentially a significant breakthrough in
the accelerated delivery of the site restoration plan. We recognise,
however, that such a change in strategy for one of the most significant
waste streams and its reclassification is of interest to a wide range of
stakeholders. We now want to test the work we have carried out so far
by submitting it to stakeholders for their
2. The PFR waste is one of three different raffinates that arose historically from reprocessing nuclear fuel at Dounreay. Raffinate from materials test reactor fuel is now being solidified in a cementation plant at the site and this is also the reference strategy for raffinate from the Dounreay Fast Reactor fuel.
3. High-level radioactive waste is generally distinguished from intermediate-level waste when it has thermal power greater than 2kW/m 3 and requires to be stored in a way that takes account of increases in temperature. The thermal power of the PFR raffinate has diminished to a maximum of 135W/m3 and cooling coils fitted to the storage tanks are no longer used. UKAEA believes the raffinate now meets the definition of intermediate-level waste.
4. More information about
Dounreay’s raffinates can be found in Public Participation Newsletter No.
4, which is being delivered today to more than 800 stakeholders. It can
also be found at
5. Decommissioning Dounreay is worth approximately £80 million a year to the economy of the Highlands in general and Caithness and north Sutherland in particular through nett salaries, pensions, contracts and sub-contracts. One in five jobs in Caithness and north Sutherland depend on decommissioning. Across Scotland, it accounts for 2,930 jobs.