In the beginning of March 2021 the Swedish nuclear regulator SSM is to provide a report to the Swedish government on the copper corrosion results from two 20-year experimental packages from the LOT project that the nuclear waste company SKB reported on in the autumn of 2020. MKG has made three inputs into the SSM quality assurance review project during the autumn of 2020. There is considerable corrosion of copper in the packages. SKB claims that the corrosion comes from oxygen that was trapped in the packages when they were started. MKG is not convinced by this explanation and finds it problematic that SKB is not in detail published the copper corrosion results of the hottest most corroded copper surfaces. New: MKG has submitted a fourth input to SSM and the KTH researchers have written to SSM a second time.
The Swedish nuclear regulator Swedish Radiation Safety Authority (SSM) has during the autumn of 2019 and into the new year been carrying out a quality assurance project on the Swedish nuclear waste company SKB’s copper corrosion results from the 20-year-old LOT experiment with copper and clay in the Äspö Hard Rock Laboratory near the Oskarshamn nuclear power plant. An SKB report (SKB TR-20-14) with the results were published in the beginning of October 2019 (se link to an article below). Miljöorganisationernas kärnavfallsgranskning MKG (The Swedish NGO office for Nuclear Waste Review) made an analysis of the report and found it clear that a considerable amount of copper corrosion – also pitting corrosion – has taken place in an environment that the organisation understands has clearly been without oxygen. This is something that should not happen according to SKB’s safety analysis for the spent fuel repository.
However, SKB claims that all the corrosion is from oxygen trapped in the experiment, an explanation that MKG does not find credible. It is now scientifically understood that repository environments with copper and clay become anoxic very fast. In the case of the LOT experiment the experimental packages have been filled with groundwater from the surrounding bedrock before closure and the starting of heating. This would surely guarantee that the conditions next to the central copper tube and the copper bottom plate that have been severely corroded were without oxygen from the beginning of the experiment.
MKG also finds it problematic that SKB is not in detail published the copper corrosion results of the hottest most corroded copper surfaces on the central copper tube and the copper bottom plate. Without this being done it not even possible to assess it the assumption the company makes about all corrosion being caused by entrapped oxygen is at all a possible explanation as the extent of all the corrosion cannot accurately be estimated.
It is now up to the SSM quality assurance review to examine the corrosion and the conditions under which it has taken place. SSM is using consultants from the UK company Galson Sciences and prof John Scully at the University of Virginia in support of the review. The work is to be completed in February when the government wants a report to use as a basis for a decision on the licensing application for the proposed spent fuel repository in Forsmark. That report from SSM to the government is now expected in the beginning of March.
In September SSM initiated the quality review of the LOT results. On September 1, a meeting was held between SSM and Galson Sciences and on October 18 a meeting was held between SKB, SSM and Galson Sciences. See the link below to an article on the Swedish part of the MKG website providing the possibility to read the minutes and download the presentations from the meeting.
MKG has been asked for input to support the SSM review and has had a meeting with the regulator and the consultants. MKG has also provided three written inputs on October 8, November 9 and December 11. The inputs can be foun below with follow-up comments on the first and third input. All the appendixes can be downloaded in the links to news articles on the Swedish web page.
New: MKG has submitted a fourth input to SSM that can be downloaded below.
There is also a link to a critical comment in Swedish about the SSM quality assurance review, also on December 11.
New: The KTH researchers have written to SSM a second time and the comments can be downloaded below.
Also, researchers from the Royal Institute of Technology have been asked by SSM to comment on the SKB LOT corrosion report TR-20-14 and have provide a very critical report that can be downloaded below.
Below is also a link to the SSM record number SSM/2020-5740 where all the documents about the regulators quality control of the results of SKB:s LOT experiment are available .
Links:
MKG’s first input to SSM review of SKB LOT results autumn 2020 201008 >>
Translation of exchange between SSM and MKG on Oct 28 and Nov 3 2020 >>
MKG’s second input to SSM review of SKB LOT results autumn 2020, 201109 >>
MKG third input to SSM review of SKB LOT results autumn 2020, 201211 >>
Critical comments by researchers from KTH to SSM on the LOT rapport TR-20-14, 201123 >>
See also the following news articles on MKG:s English pages:
Östhammars community tells the government they accept the repository for spent fuel, 201013 >>
SKB will publish LOT project results and SSM will do a quality control 200325 >>
SKB sends complementary information on copper corrosion to the government 190404 >>
