The Grimsel Test Site Newsletters highlight major activities at the GTS on a regular basis and try to bring the “flavour of working underground” closer to you.

December 2023

newsletter 009ISCO MEETING 2023
First of all, I would like to highlight this year’s Grimsel Test Site International Steering Committee Meeting (ISCO), which took place on June 6th and 7th, 2023, at the Hotel Handeck on the Grimsel pass road together with our international partners. The focus of the first day was on technical sessions, providing updates on ongoing RD&D projects. Discussions also included the presentation and review of planned new projects, which make up an essential part of our preparations for the next 5-year laboratory phase. The second day witnessed the GTS Executive Board meeting, where strategic, scientific, and operational matters were deliberated, leading to crucial decisions. Pre-parations for the 40th-anniversary celebration of the Grimsel Test Site next year are well underway, guided by an advisory committee comprising several GTS partners.

Among other topics, the focus of this newsletter are selected updates on ongoing GTS projects highlighting the “Material Corrosion Test” (MACOTE) and the “Gas- Permeable Seal Test” (GAST) projects, for which important project milestones have been reached. All other project activities are covered in the regular update note.

Also, the courses and workshops held within the framework of the Grimsel Training Centre (GTC) significantly contributed to knowledge retention and transfer, which are increasingly vital concerns. The report on a one-week student training course on structural mapping and geochemical/geophysical methods in and around the GTS is also worth reading.

We are honored to have Jens Birkholzer from the Lawrence Berkeley National Laboratory in Berkeley, California, as our guest editor. Jens has been a constant supporter and influencer of the Grimsel program for nearly a decade, and we look forward to continuing this fruitful collaboration for several more years. We extend our sincere thanks to him for his unwavering support and his valuable contribution to this newsletter.

We hope you find the newsletter informative and interesting and, as always, we look forward to your valued feedback..

I wish you a happy end to the year and a relaxing New Year break.

Head of Grimsel Test Site (GTS)

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January 2023

newsletter 006For Nagra in particular, 2022 has been a very exciting year with the publication of our site proposal for the future deep geological repository (DGR) for the radioactive waste in Switzerland ( It will be in Opalinus Clay in the region called „Nördlich Lägern“ (see map). This is an important milestone which will also have an impact on future research, development and demonstration (RD&D) activities in the Swiss underground research laboratories (URL).

nordlich lagern
Map:Nagra’s siting proposal (September 12, 2022) „Nördlich Lägern“ representing the site with the best waste containment capacity, the greatest long-termstability, and largest underground spatial flexibility to accommodate the deep.

The RD&D activities at the Grimsel Test Site (GTS) over the last decades have alsomade a significant contribution to the achievement of this important milestone. For example, the GTS has helped to develop and test rock characterization methods and tools suitable for the site selection process in Switzerland. At the same time, it has been possible to extend the understanding of key processes in the geological and technical barriers and to test the performance of components of the DGR concepts under conditions relevant to deep disposal on realistic scales within the framework of GTS projects. And last but not least, the many visits, workshops and media events at GTS since its inception, which have been instrumental in building trust and making our workmore visible.

The GTS programme will increasingly contribute tomeeting the challenges of the DGR implementation phase in the coming years, in particular, with projects for the optimization of disposal concepts or individual components, of processes, and of engineering and monitoring aspects in preparation of the facilities including the underground research laboratory at the disposal site.

In addition, we are pleased that Dr. Jonathan Martin (NWS, UK) has agreed to contribute to this issue as a guest editor. We would like to take this opportunity to thank him for his contribution. As amember of theGTS ExecutiveGroup,NWS and Jon have been committed to the projects of the Grimsel Test Site with great dedication for many years, and we look forward to the coming years with great pleasure and anticipation.

As always, we hope you find the content of the GTS Newsletter interesting, enjoy reading it and we appreciate your feedback.

Head of Grimsel Test Site (GTS)

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July 2022

newsletter 006The first half of the year is already over and, at least with regard to COVID 19, there are signs of normalisation. Activities at the Grimsel Test Site have returned to pre-Corona levels in terms of the onsite presence of partners, contractors and guests, and after two years of online meetings we were finally able to hold another physical ISCO (International Steering COmmittee) meeting with the Grimsel partner organisations in the Bernese Oberland at the beginning of June.

The two-day ISCO meeting was divided into technical sessions (focus: update on ongoing projects and presentation of new project ideas) and an executive session with the FLG partner organisations (focus: organisation and operation of GTS, financial status and planning of the next project phase), complemented by a visit to the Grimsel Test Site. With more than 30 participants from North America, Asia and Europe it was a very intensive and successful meeting.

A special highlight of this year's ISCO meeting was the handing over of the function as chairperson of the ISCO meeting. Due to his upcoming planned retirement, Stratis Vomvoris (formerly Division Head International Services & Projects, Nagra) handed over this function to Irina Gaus (Head of Research and Development,Nagra) after 25 years.

Stratis was thanked for his outstanding support of the Grimsel Programme in this function and his personal commitment over the past decades. Irina was warmly welcomed as the new Chair and we are convinced that, as Nagra's Head of R&D and with her international experience and reputation, she will be very successful in this important leadership role.

Isco chair 2022
Left to right: Section Head of GTS Dr. Ingo Blechschmidt, new ISCO-chair Dr. Irina Gaus and former ISCO-chair Dr. Stratis Vomvoris (ISCO 2022). © Comet Photoshopping GmbH, Dieter Enz.

In this newsletter, we want to highlight the most important events in the projects and inform you about what else is going on. Concerning projects: (i) Gas-Permeable Seal Test (GAST) - after themany years of preparation and testing, the final experiment phase with the main “gas flow test" (GFT) started at the beginning of May 2022 successfully. (ii) Much has already been shown about the implementation of the HotBENT project, in this issue we want to inform you about the status of the "hot phase".

We would also like to take this opportunity to thank Dr. Axel Liebscher (BGE, Germany) for his editorial guest contribution in this issue. As a relatively new representative in the GTS Executive Group, he and his colleagues have shown great commitment and dedication to the projects at the Grimsel Test Site from the very beginning, and we look forward to the coming years with great pleasure and anticipation.

We hope that you will find the content of the current newsletter interesting and enjoy reading it. And as always, we are looking forward to your feedback.

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December 2021

newsletter 006The year 2021 is drawing to a close and it is time again to review the last 6 months. Unfortunately, these months were again overshadowed by the ongoing COVID-19 pandemic and many of the originally planned activities could not be carried out as hoped. After almost 2 years of COVID-19-related restrictions, we have become cautious about making predictions and are trying to deal with the situation as best we can and make the best of it.

This year’s International Steering Committee Meeting of the GTS partners (ISCO2021) was held in September (as decided at the beginning of the year), unfortunately only online again.

Optimistic as we are, we have planned the next ISCO meeting as a physical meeting in Switzerland for June 2022. Online meetings as information meetings do have their advantages, so it was possible to welcome almost 60 participants from all participating organisations during the technical-scientific sessions and to informand discuss about the progress in the different projects and future joint activities.

The technical part was complemented by the subsequent Executive Meeting of the Grimsel Partner Organisations. Yet, there is certainly a great benefit of physical meetings to discuss new projects or advances in more detail.

In this issue we focus in particular on (i) the successful completion of the installation of the HotBENT experiment - represented by a "pictorial" journey through the last more than 12 months of intensive installation activities, (ii) the start of the circulation of the radioactive tracer cocktail of the CIM project and (iii) the activities in the framework of the Grimsel Training Centre (GTC) with an outlook on the programme in 2022.

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June 2021

newsletter 005It has already been half a year since we informed you about the latest developments at the Grimsel Test Site. Despite the ongoing COVID-19 pandemic and the associated restrictions, aswell as a long rather harsh winter, the first sixmonths of 2021 were again very intensive. Due to the still limited travel possibilities for many countries, we have decided to postpone the annual meeting of the International Steering Committee of GTS (ISCO) until September this year (22 to 23 September 2021). We hope that a face-to-face meeting or at least a hybrid variant approach will be possible again then.

Our activities onsite were particularly marked by the further emplacement works of the HotBENT (High Temperature Effects On Bentonite Buffers) experiment. In addition, it was of course also important to give all other ongoing projects and activities the appropriate attention and support - more information on those in the two focus articles and the updates in this issue.

A successful and very fruitful inspection by the Federal Office of Public Health (FOPH) at the beginning of the year inspired us to shed a little more light in this issue on the pioneering work with radioactive tracers at the Grimsel Test Site.

Furthermore, we are pleased to welcome the Federal Company for Radioactive Waste Disposal in Germany (BGE), the German implementer, which decided to participate in the GTS activities starting fromthis year.

Another highlight of recent weeks was the visit by Nagra's new CEO, Dr. Matthias Braun, who took over this responsible position in March this year, succeeding Dr. Thomas Ernst, who is retiring in autumn this year. During the visit, he and Prof. Dr. Lino Guzzella (the new President of Nagra's Board of Directors) learned about the laboratory's current activities. Both emphasised the important role of international cooperation in radioactive waste RD&D being carried out at GTS. We hope that in the second half of the yearwe can carry out at least a few of the courses planned within the Grimsel Training Centre (GTC) programme and start with new project phases.

We would like to thank Hiroyuki Umeki (from NUMO, Japan) for his guest editorial contribution. In the thirty-seventh year since we started the Grimsel Test Site scientific programme, we are pleased to have a contribution from a colleague who himself and the organisations he represented overmany years havemade a significant contribution to the success of the laboratory.

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December 2020

newsletter 004Right at the beginning I would like to thank my colleagues who have contributed to this newsletter. As for many of us, this year has evolved differently than planned. After the short-lived relief in the summer, the virus caught up again with us in the second half of the year. Given the impact of the COVID-19 pandemic, which has already caused much suffering and pushed social life to its limits, it is not that easy to distil the positive out of this year.

Nevertheless, such challenges often reveal our strengths better than any other situation. We are very pleased to report that the Grimsel team has been able to maintain operations at the Grimsel Test Site and achieve the important milestones in this very challenging year. We believe that we have been able to meet our partners' expectations despite these circumstances.

Some activities had to be postponed to next year, most notably the training programme of the Grimsel Training Centre, which could not be carried out as planned. After the short break and rest of the Christmas season, we will resume in 2021 with the same energy and enthusiasm that colleagues and partners know and expect from us.

For GTS, 2020 – especially the second half of it – was the year of the HotBENT experiment, which was started on schedule thanks to the tremendous efforts of an excellent international project team. Further information is given on the following pages.

Furthermore, we are pleased to welcome the Federal Office for the Safety of Nuclear Waste Management (BASE), the German regulator, which decided to participate in the GTS activities starting from this year.

Finally, I would also like to thank our colleague Irina Gaus - RD&D coordinator at Nagra - for her guest editorial contribution.

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newsletter 01 pages

June 2020

newsletter 003On June 3rd and 4th 2020, the annual GTS International Steering Committee meeting (ISCO 2020) took place. This year, however, under very special circumstances due to the COVID-19 pandemic.

During the course of planning of this year’s ISCO 2020 meeting we had many discussions on how to proceed and whether we should postpone the meeting altogether. Finally we came to the conclusion that it is better to hold the meeting and meet our colleagues from all over the world - just in a little bit different fashion than in the past years. Thanks to modern communication technology it was possible to report on GTS activities, to discuss and exchange information about upcoming tasks.

Of course, it was not the same as the usual meeting, because, as many of you know, one of the main advantages of the ISCO meeting is to meet and talk face to face. Spending time together, not only discussing important radioactive waste management issues, but also taking care of long-standing relationships between our organisations and building new relationships has always been of paramount importance for a such small community.

Since mid-March 2020, Switzerland, like many other countries, has been in COVID-19 lock-down. Nevertheless, GTS operations have been maintained thanks to the rapid introduction of appropriate measures and now we hope that we will soon be able to return to normal operations.

However, a direct consequence of the COVID-19 pandemic is that all Grimsel Training Center (GTC) courses were postponed to 2021. Please visit our website for further details.

Many thanks to all who contributed to this newsletter with interesting content and in a timely fashion. Also, a warm thanks to Prof. Dr. Thorsten Schäfer for his guest contribution.

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December 2019

newsletter 002In June of this year, the annual meeting of the International Steering Committee (ISCO) of the Grimsel Test Site (GTS) took place in the nearby Hotel Handeck. As every year, the ISCO meeting was dedicated primarily to the scientific and financial governance of the entire GTS programme. All Grimsel partners are invited annually to learn about current projects and planned activities, to exchange ideas and to agree on the future strategy of joint research activities at the GTS.

In addition, 2019 was a special year as we celebrated the 35th anniversary of the GTS and launched the next 5-year programme. The success of the programme is also reflected in the long-standing relationship between organisations and individuals participating in the activities.

The Spanish Radioactive Waste Management Agency (ENRESA), one of the many partner organisations at the GTS, has been involved in our activities for many years and has contributed to the success of many projects. To commemorate this, we asked our long-time colleague Juan Carlos Mayor to contribute with a guest editorial message to this second edition of the GTS Newsletter.

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April 2019

newsletter 001For 35 years, Nagra and its partners have been conducting underground research projects at the Grimsel Test Site (GTS) to contribute to the development and confirmation of safe geological disposal concepts and to the characterisation of suitable host rock formations. Over the years, the results of this internationally recognised research programme have been, and continue to be, incorporated directly into exploration programmes, modelling, safety and engineering feasibility studies on options for the realisation of deep geological repositories.

From the start, the GTS has been a platform for focused international research and cooperation. Currently there are more than 20 partner organisations from 12 countries, who steer the GTS activities and secure a state-of-the-art RD&D programme. In 2018, we welcomed KIGAM (Korea Institute of Geoscience & Mineral Resources) as a new member of the GTS family.

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