WASTE MANAGEMENT | FORSMARK VAULTS ADVANCE Forsmark (2002-2007)’. Forsmark could thus locate
a vault deeper than first thought – and, at a depth of around 470m, comparable to that offered by Oskarshamn. Additional aspects related to post-closure safety were decisive in choosing Forsmark as the site. By the time SKB made its choice in 2009 hundreds of scientific reports had been produced and 25 cored boreholes drilled. Of these, 19 were more than 500m depth and a further nine went to more than 1km depth. In 2011, SKB filed an application to build and operate the high-level facility abnd government approval was granted in early 2022. A year ago, SKB was granted an environment permit to start construction and by mid-2025, it had signed a collaboration agreement with Implenia for the major initial tunnelling works required.
Preparing to excavate Implenia is to plan and perform detailed design and then excavations for the 5km-long spiralling access tunnel to reach some 470m below the surface and the ‘central’ base area. In addition it will excavate the first of the local grid of large tunnels for various operational activities at the base of the shafts and access tunnel; and, also the initial transport tunnels that will open up the first repository storage zones. Implenia is also to design and build three deep shafts down to the repository level. The shafts are for ventilation and a lift, also to serve and support the activities of the underground complex over the coming decades of its operational life. In Q3 of this year, the contractor began mobilising on site. Upon final safety approvals from the national radiation safety authority, StralSakerhetsMyndigheten, and after further preparatory works on the surface, the first excavations would then begin. Excavation of the shaft, access tunnel and the initial
Below: Illustration of the conceptual layout for underground storage vault for spent nuclear fuel at SKB’s Forsmark site. Credit: SKB
repository-level tunnels are anticipated to take about eight years to complete. The full scale of the underground repository, though, is far more extensive. Current expectations are than the repository will have been fully extended in some 60 years’ time, by the 2080s. By then, it is anticipated that some 66 km of tunnels will have been excavated, within a grid network covering an area of 4km²,. Expectations are that around 2.7m m³ of rock will have been excavated to form the tunnels at the repository level, and also the access tunnel and shafts from the surface. The scale of excavation is greater than the 1.85m m³ that had
been initially discussed before Forsmark was picked over Oskarshamn as favoured candidate to be the host site.
Disposal SKB says that when the repository has finished excavating its first access, base, transport and storage tunnels then disposal of spent fuel can begin. The present timeline anticipates the disposal activities should be able to commence in the 2030s. The deposition storage tunnels will terminate in
dead-ends. Along each ‘deposition’ storage tunnel will be regularly spaced small silos carved into the rock, each to receive a single canister. The silos will then be backfilled with bentonite clay, the silo tunnels are then to plugged and sealed off as the area is filled. This is the ‘KBS-3’ storage concept.
The tunnels linking to the silo storage locations will also
be sealed off, eventually, as will the entire vault, on its completion later this century. Only a few of these branch tunnels are to be in use at any one time. Operational storage activities, therefore, will gradually
back out of each deposition tunnel, eventually to be filled completely, back to the junction with the main transport tunnel. Ultimately, with all the branch deposition tunnels leading off a particular transport tunnel having been filled, then that main tunnel itself be filled. The plan is for Forsmark to host approximately 12,000 tonnes of spent fuel to be held in 6000 canisters.
Other excavations at Forsmark Excavations also started at Forsmark recently for the extension of the shallower-depth vault for short-lived radioactive waste. The existing vault is about 60m and more below the ground surface and has a storage capacity of about 63,000m3. Rock blasting 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. The tunnelling works involve the creation of six 275m-long caverns. 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 Swedish 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 surveys, to monitor key areas of the infrastructure. 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 and located at a depth of about 500m. ■
38 | WNE Special Edition |
www.neimagazine.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108
