Engineering news
There is no “fundamental contradiction” between the need to seal a geological repository for high-level nuclear waste and the possibility of having to vent the gases that might build up within it, an expert at the Environment Agency has said.
Dr Clive Williams, policy development manager for radioactive substances regulation, told PE today that concerns over the build up of gases within a repository should not hinder the site selection process for the chamber. “With regard to retaining gases within a repository and the relief of pressure [from the build up of gases], we see no reason why they should be fundamentally contradictory so as to prevent a site selection process from proceeding,” he said.
Williams’ comments came in the wake of concerns voiced by experts that the impermeable nature of a repository ran contrary to the need to vent gases that would build up within it. Experts believe that gases generated by metal corrosion and degradation of organic waste would be likely to accumulate within a geological repository. The main gases produced would be hydrogen, carbon dioxide and methane. These could contain radioactive isotopes such as tritium and carbon 14.
It is thought that if gas built up within the repository it could have an impact on its structure. Nuclear Waste Advisory Associates warned last month that this meant it could be necessary to vent radioactive gases, increasing the risk of those exposed to developing cancer.
Williams said the issue of gas build-up had been under consideration for some time by developers of repositories and the regulatory authorities. “It’s something which we have focused on at the Environment Agency, and it’s one of many issues that we’ll be taking forward in our scrutiny of the Nuclear Decommissioning Authority’s (NDA) work.”
He added that, since the build up of gases inside a repository was dependent on its geological characteristics, the site selection process should go ahead. “There will be more work that will be needed if and when the candidate site for such a disposal facility is identified in this country,” Williams said.
The Environment Agency’s relationship with the NDA was “open and transparent”, Williams said. He said he expected the NDA to report on issues surrounding the development of a repository in the coming months.