§ The Secretary of State for Environment, Food and Rural Affairs (Margaret Beckett)We have, today published the joint decision that the Secretary of State for Health and I have made in response to the Environment Agency's Proposed Decision on the Future Regulation of Technetium-99 Discharges from British Nuclear Fuels plc's Sellafield site into the Irish sea.
At the request of Ministers, the Environment Agency has carried out a review of technetium-99 (Tc-99) discharges from Sellafield in advance of the review of other radioactive discharges from that site. Our request for a faster track review was in response to the concerns raised by other countries that Tc-99, which is very mobile in the marine environment, had been detected at 21WS low levels off the coast of Scandinavia and further afield. The dominant source of Tc-99 discharges from Sellafield is the reprocessing of spent Magnox reactor fuel. There is no evidence that Tc-99 at these levels, or the levels found in UK waters pose any credible threat to human health or that of marine organisms. Nevertheless, its presence has been a source of concern to a number of our international partners.
In. September of last year, the Environment Agency published its proposal for the future regulation of Tc-99. It was then for the two Ministers with responsibility under the Radioactive Substances Act 1993, the Secretary of State for Health and I, to consider whether we wished to direct the Agency to take some other course of action.
In the response that we have published today, we see no reason to direct the Environment Agency to take a different course to the one it has proposed, but we do propose to go further. The details of our decision are set out in the published document, copies of which have been placed in the Libraries of both Houses. It will also be available via my Department's website.
In essence, the Agency has proposed two types of abatement technology that would allow the Tc-99 discharge limit to be reduced from 90 TBq per year to 10 TBq per year by 2006, or possibly sooner. Two different types of abatement technology are required because of the chemical differences between newly produced Medium Active Concentrate (MAC)—a liquid mixture produced during Magnox fuel reprocessing—which contains Tc-99 as well as other more dangerous radionuclides, and stored MAC.
We expect that, subject to HSE agreement and the technology proving to be successful, newly produced MAC will be diverted into a different waste stream early next year. Treatment of MAC in the process designed to deal with the much more radioactive "Highly Active Liquor", will lead to the MAC (containing Tc-99) being converted into glass blocks which will be suitable for long term storage. There would, therefore be no further Tc-99 discharges arising from newly produced MAC and the discharge limit could be reduced to 10 TBq/year by 2006.
Because it is chemically different, MAC that is in store cannot be dealt with using the "MAC-Diversion" approach. That source of MAC could, potentially, lead to Tc-99 discharges above 10 TBq/year until 2006. Theoretically, stored MAC could be treated with a chemical called tetraphenylphosphonium bromide (TPP) which would cause it to solidify and allow it to be removed from the treatment plant along with the other more dangerous components of MAC, which are already solidified prior to removal by a separate process. 22WS The solid mixture produced would not be suitable for conversion into glass blocks, but it could be mixed with cement and stored in steel drums. The technology behind the use of TPP is, however, not as proven as in the case of MAC-Diversion. The further research work identified by the Environment Agency in its proposed decision would need to be completed successfully to be sure that TPP itself would not pose an unacceptable risk to the marine environment; that workers were not to be subjected to unacceptable risks; and that the presence of TPP in the stored waste would not facilitate leaching of not just Tc-99 but other, more radiotoxic chemicals from the stored waste to create unacceptable risks for future generations.
The potential problems surrounding the use of TPP are not necessarily insurmountable, but they will take time to address. The simple expedient of continuing to store MAC in the tanks and building in which it is currently housed, to allow time for TPP research to be carried out, is not available. That building and tanks were constructed during the 1950s/60s; they were not built to modern standards; and they have already exceeded their expected lifetimes. The HSE keeps the storage facility under continual review and its advice is that while the facility is currently safe for use, that may not be the case beyond 2006. Under these circumstances it would be irresponsible to plan for MAC to still be in those tanks beyond that date. There is, however, another approach that could be taken.
I am consulting on my proposal to direct the Environment Agency to consider whether it would be possible to impose a moratorium on the discharge of Tc-99 from the Sellafield site whilst TPP research is being carried out. As part of their consideration, I would expect the Agency to review the storage options for Medium Active Concentrate (MAC) beyond 2006, particularly considering work which has been done by BNFL on the practicalities of refurbishing the storage tanks and building. If a moratorium were to be introduced and, in the worst case scenario the research shows that TPP abatement cannot be made to work, the remaining Tc-99 contained in the MAC storage tanks would need to be discharged into the Irish sea quickly, depending on the judgment of Nuclear Installations Inspectorate inspectors about the integrity of those tanks.
The Secretary of State for Health and I have also considered whether the two types of practice which generate Tc-99—namely, the processing of spent Magnox fuel and the reprocessing of spent oxide fuel—are justified. We consider that both of these practices are covered by the requirements of Article 6(2) of Directive 96/29/Euratom and that the question whether to undertake a review of justification under this Article should be considered at a later stage.