The Swedish Society for Nature Conservation and Miljöorganisationernas kärnavfallsgranskning (MKG, The Swedish NGO office for Nuclear Waste Review) had a meeting on March 25th with the General Director of the Swedish Radiation Safety Authority and staff. At the meeting it was revealed that the nuclear waste company SKB had already in December told the regulator that copper corrosion results from the 20-year LOT experiment packages that were retrieved in the autumn of 2019 would likely be published in the first half of 2020. SSM has started a process to do a quality control of the results. This means that the results can be part of the basis of the government's ongoing admissibility review of the plnned repository for spent nuclear fuel in Forsmark. Update: SKB copper corrosion results to be published by the end of September, and the SSM quality control to be done by the end of the year with support from Galson Sciences.
In response to a direct question from MKG at meeting on October 16 organised by the Swedish Radiation Safety Authority SSM, the nuclear waste company SKB answered that experimental packages in the LOT experiment have been retrieved – without transparency to any other actors. The LOT test is carried out in the Äspö hard rock laboratory to test the long-term effect of a heated copper tube on surrounding bentonite clay and copper samples.
MKG has for a long time wanted the next LOT experimental package retrieved. The analysis of copper corrosion in the retrieved 20-year old LOT packages can decide the issue of the suitability of copper as a canister material in the planned. The latest package was retrieved in 2006 after 5 years heating and there was an unexpected amount of copper corrosion, especially on the heated copper tube. There was an attempt to explain this by all oxygen locked inside the package causing corrosion, but this explanation is not convincing as much of the oxygen would have been consumed in the surrounding clay and groundwater before reaching copper surfaces.
After a further 15 years any major increase in copper corrosion can certainly not be explained in the same way. If the copper surfaces look anything like the copper in the Swiss FEBEX experiment, with up to 0,1 mm pitting corrosion, it is certain that copper should not be used as a canister material for a spent fuel repository (link to article in Swedish with the FEBEX results).
The nuclear waste company SKB in the autumn of 2019 stated that new LOT results on copper corrosion would not be made available until in several years, after the Government has taken decisions on the licencing of the planned repository for spent nuclear fuel in Forsmark.
During the autumn of 2019 and beginning of 2020 MKG had a dialogue through written correspondence with the Swedish Radiation Safety Authority, SSM. The Swedish Society for Nature Conservation, Swedish Friends of the Earth and MKG have continuously kept the government informed about the exchange of letters and the importance of having the copper corrosion in the newly retrieved 20-year LOT experimental packages analysed. MKG had come to the understanding that SSM was relatively uninterested in the results from the LOT experiment.
The Swedish Society for Nature Conservation and MKG had a meeting on March 25th with the General Director of the Swedish Radiation Safety Authority and staff. At the meeting it was revealed that the nuclear waste company SKB had already in December told the regulator that copper corrosion results from the 20-year LOT experiment packages that were retrieved in the autumn of 2019 would likely be published in the first half of 2020. SSM has started a process to do a quality control of the results. This means that the results can be part of the basis in the government's admissibility review of the repository.
MKG and its member organisations the Swedish Society for Nature Conservation and the Swedish Friends of the Earth are very happy about this development that possibly is the result of actions from SSM. The organisations on April 28th made a special statement to the government informing of the developments regarding the possibility to use the copper corrosion results from the LOT packages in its ongoing review of the proposed repository for spent fuel in Forsmark.
Update: SKB published a report with information about the two experimental packages and their retrieval in June. A second report with the copper corosion results are to be published by the end of September. The SSM quality control is to be completes by the end of the year and the regulator has contracted support from Galson Sciences to assist.
See also the following news articles on MKG:s English pages:
SKB sends complementary information on copper corrosion to the government 190404 >>
