The Radioactive Waste Management Advisory Committee believes the nuclear industry has consistently overestimated how fast it can build a repository. By trying to keep to too tight a timetable, the committee warns, the industry may jeopardise its chances of being able to prove that the repository will safely retain its radioactivity in the future.
UK Nirex, the industry's waste disposal company, has chosen a site about 650m (2,133ft) underground near the Sellafield reprocessing plant in west Cumbria for its repository. But even if all goes well, Nirex will not have it operating before 2010 at the earliest, according to the committee.
Nirex proposes to excavate an underground laboratory to investigate the suitability of the rocks and underground geological formations at the Sellafield site. But while the committee welcomes the move, it warns that Nirex is trying to press ahead too quickly with sinking the main shafts.
The main factor in the long- term safety of the repository is the flow of underground water which could dissolve radioactive materials and bring them back to the surface, possibly to contaminate drinking water. By sinking the access shafts to the laboratory, Nirex will change the natural patterns of groundwater flow.
The committee says that Nirex should monitor the flow of groundwater for at least 18 months to two years before it starts excavating the shafts. And, in what could be a costly recommendation, it says that the shafts should have a watertight lining down their entire length.
The committee also thinks Nirex should allow time for the trial disposal and subsequent recovery of radioactive wastes, as is being done in the US and Canada. 'Such precommissioning trials could become an internationally accepted best practice,' the report says. The experiments could take a further five years, pushing the timetable back to 2015.
UK Nirex said yesterday it had refined its plans and would freeze the rocks at the top of the shaft excavations to stop disturbance of underground water flows. The company would be seeking clarification of the suggestion that trial emplacement and retrieval of waste might be required, and would give the suggestion 'full consideration in planning its forward programme'. The company added: 'The timing of every stage will be managed pragmatically and if we need to take longer at any stage then we will do so.'
Response by the Radioactive Waste Management Advisory Committee to UK Nirex Ltd's Consultative Document on a Rock Characterisation Facility. Department of the Environment, February 1993.Reuse content