Excursion to Wismut

Following this year's general meeting of the Nuclear Society, participants had the opportunity to visit the Schlema-Alberoda remediation site of Wismut GmbH. As a participant, I was impressed by the depth of the insights - both into the eventful history of uranium mining in the GDR and into today's technical, radiological and ecological challenges.

Between 1946 and 1990, 216,300 tonnes of uranium were mined at the site - a significant proportion of this as reparations to the former Soviet Union. Mining has been documented in the region since the Middle Ages. The so-called "Schneeberg disease", which remained a mystery for centuries, was particularly influential. Today it is known that it was lung cancer caused by radon - a finding that emphasises the importance of radiation protection today.

During the tour, the measures taken by Wismut GmbH to minimise radiation exposure from radon were impressively demonstrated. The radiological situation is monitored by active dosimeters and continuous air measurements, particularly in the vicinity of the waste rock piles. The following applies: as an alpha emitter, radon is particularly relevant when it is inhaled. The legally permissible indoor limit value of 300 Bq/m³ serves as a reference here. The fact that the biological damage caused by alpha radiation is around 20 times higher than that caused by gamma sources makes careful handling all the more important.

Another focus was on the handling of mine water. The site operates six purification plants that continuously pump and decontaminate contaminated water in order to prevent any risk to the environment and drinking water supplies - as is the case with many other mining projects. It was particularly interesting to learn that even small amounts of uranium (around 1.1 mg/l) are still dissolved in the mine water. With a throughput of around 1,150 m³ per hour, this results in a recovery volume of around 11 tonnes of uranium per year - an impressive figure in the context of remediating contaminated sites.

A frequently asked question was whether there were still recoverable uranium deposits on the Wismut site. According to SDAG Wismut's final report from 1990, the projected resources are estimated at around 74,000 tonnes of uranium. In mathematical terms, this would correspond to around 9,500 tonnes of enriched uranium, assuming a current enrichment of 5 % and standard tails of 0.1 %. A fascinating thought, even if economic production no longer plays a role at present.

The tour also made it clear that the average uranium ore content at the time was 0.1 % - relatively low compared to other uranium ore deposits. This emphasises that the mining at the time was not primarily economically motivated, but was driven by geopolitical and strategic interests and primarily served as a reparation payment.

My conclusion: The excursion to Wismut was an extremely instructive conclusion to an already successful community meeting. My special thanks go to Wismut GmbH for the technically excellent guided tour and to the KTG organisation team for the opportunity to experience this historic and technically highly relevant site for myself. The visit impressively demonstrated to me how ambitiously, thoughtfully and responsibly the legacy of uranium mining is being dealt with in Germany.

Caspar Gutsche