February 15, J.-L. Lachaume of the French Nuclear Safety Authority (ASN) wrote to the director of Andra, the nuclear waste authority, in regard the maintenance of La Manche Storage Center (CSM) for essentially short-lived waste of “low”- and intermediate-level radioactivity. The Permanent Group of Waste Experts had examined various reports that Andra had submitted in 2009 as required by the decree of 2003 authorizing the first phase of surveillance at the site. One of the reports was on the advisability of installing a more durable cover over the waste. As a result of the experts’ report, ASN is imposing various requirements on Andra that are a reminder of the difficulties of safeguarding radioactive waste over the long term.
The experts found that the behavior of the CSM conforms in general with Andra’s forecasts. However, the behavior is complex and needs interpretation based on numerous observations, supported by modeling The current surveillance system must be continued and the modeling increased. The next annual surveillance reports must evaluate the rate of infiltration through the geomembrane now over the waste. Within two years Andra must present an interpretation of the evolution of levels of tritium in the drainage network, in the water under the center, and in the streams to the north-west of the center and integrate them into the existing hydrogeologic model. In its next revision of the site’s safety report, Andra must specify how water from the site will be handled, if the facilities now used for this purpose become unavailable or disappear because of the dismantling of Areva’s La Hague establishment. (Water contaminated at the storage site is now released into the ocean or into a stream by Areva.)
As to the cover, Andra plans to make gradual changes. It intends to reinforce the embankment at the site and then, over fifty years, reduce the steepness of the slope and install a mineral (inorganic) cover over the existing cover. ASN states that additional information is necessary to determine whether Andra’s plans are feasible and that within five years Andra must submit a report, which includes proof that the stability of the embankment can be maintained if the drainage equipment becomes degraded or if there is an earthquake. It also must include the evolution of the storage site in the very long term, taking into account the different possibilities for the land around the storage site, -in particular for those occupied by Areva-La Hague after that establishment is dismantled.
Andra must in addition evaluate and improve its archives pertaining to the site.
In other words, the CSM is not ready to go from the “very active surveillance” phase to the “active surveillance phase.”
–Mary Byrd Davis
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