Left:


A research tunnel at the Äspö Hard Rock Laboratory


Eventually, and ultimately, with all the branch


deposition tunnels leading off a particular transport tunnel having been filled, then that main tunnel itself be filled. Meanwhile other sections and arrays of branch


tunnels will have been opened up in the granitic rock for what is planned to be a vast repository. The process will continue, systematically, over decades.


OTHER EXCAVATIONS AT FORSMARK Excavations started at Forsmark recently for the extension of the shallower-depth vault for short-lived radioactive waste. The existing vault is about 60m and deeper below


the ground surface and has a storage capacity of about 63,000m3


. Rock basting for the new section began


almost a year ago and is to add twice as much storage capacity as the original, at depths of about 120m-140m below the surface. The tunnelling works involve creation of 6 x 275m-long caverns, tunnellers were told mid-year by SKB at the WTC 2025 conference. The new storage section will take the total capacity of this vault to about 180,000m3


. The expansion project received approval from environmental authorities in late 2022. Tunnelling work


is being undertaken by contractor Skanska, which was appointed in mid-2023. With SKB obtaining approval for the works from the radiation safety authority, in November 2024, first blasting began soon after. It is anticipated the construction work and fit-out will be completed around 2030. In addition to holding radioactive waste from


the healthcare and industry sectors, and research, the expanded vault is also to take waste from the decommissioning and dismantling of Swedish nuclear power plants. The power plant waste is to include reactor components and building materials. Recently, the maintenance teams on the existing


vault have borrowed lessons and experience from the neighbouring power plant teams to use the latest drone technology for remote and effective surveys, to monitor key areas of infrastructure assets. SKB says this helps with the accessibility, speed, frequency and cost of inspections of the existing underground storage facility. In future, a vault for long-lived radioactive waste


is also required and SKB has not yet selected the site. The vault is foreseen as requiring a storage capacity of approximately 16,000m3 about 500m.


and be located at a depth of


REFERENCES ● Alvarez, D. L. & Lingren, E. (2025) ‘Underground facilities in Sweden for the radioactive waste


disposal program.’ World Tunnel Congress (WTC), May 2025; Stockholm


● Alvarez, D. L. & Lingren, E. (2025) ‘Characterisation of the rock mass during excavation of the spent fuel repository at Forsmark, Sweden.’ WTC 2025; Stockholm


● Site Investigation: Forsmark (2002-2007); SKB ● Final repository for spent fuel in Forsmark: basis for decision and reasons for site selection. SKB, June 2009


● Methodology for rock mechanics modelling of the Forsmark site. SKB report R-20-13; Dec 2022


● Forsmark site investigation Overcoring rock stress measurements in borehole KFM24. SKB report P-25-02; May 2025


● The glacially induced stress field in Forsmark: Simulations with past and future ice sheet models. SKB report TR-25-03; Aug 2025


● Geoscientific Single Hole Interpretation (GSHI) of KFR90 and KFR91. SKB report P-24-05; Sep 2025


October 2025


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