ONKALO hoist building reaches rooftop height
Work on the second phase of the ONKALO hoist building in Olkiluoto has reached rooftop height. After the second phase is complete, a personnel lift providing access to the underground facilities of ONKALO can be installed into the hoist building. The personnel lift will be the primary means of accessing the final disposal research tunnel for spent nuclear fuel, which reaches a depth of nearly 450 meters.
The current second phase continues the work of the first phase of the ventilation and hoist building that was completed in 2011 and included the ventilation building and its underground connections with ONKALO. The building complex now also includes the hoist building, which will have, among other things, facilities for a personnel lift.
The construction of the second phase of the ventilation and hoist building began in summer 2014. In addition to the facilities for the personnel lift, the second phase includes access routes to the encapsulation plant and disposal facility, as well as access control facilities for the ONKALO area. The outer constructions of the access control building will be built to their final dimensions, but the facilities and systems will only be completed and equipped as part of the construction work subject to a construction license after the license currently being sought has been granted.
“The personnel lift to be installed into the hoist building will replace the vehicle access tunnel as the primary means of transporting personnel into the underground facilities”, said SVP Erkki Palonen from Posiva, who is in charge of the project, at the topping out ceremony for the hoist building.
“The hoist building has already undergone several modifications in the design phase. As thorough design work will guarantee the best results, we are now happy with the end result and the functionality of the building”, Palonen said.
The design of the second phase of the hoist building has taken into account the different phases of the construction work. This will ensure that the systems and functions of the building will also work as a part of the final complex. The building will be gradually commissioned as work in ONKALO proceeds.
The gross area of the hoist building, which constitutes the second phase of the ventilation and hoist buildings, is 2,180 m2, with a total volume of 10,010 m3. Including the facilities of the first phase of the complex, the gross area of the hoist building is 2,800 m2, and its total volume is 12,000 m3. The building reaches 20.90 metres above ground level. The hoist building also contains an air raid shelter for the more than 150 people working in the ONKALO area.
The main contractor for the hoist building will be Hartela Oy. The contractor for the ventilation system is Ilmastointi Salminen Oy, for electrical installations Sähkö-Rauma Oy, and for HPAC work Vesi-Vasa Oy.
All three shafts used for ventilation and transporting personnel at ONKALO are located in the vicinity of the ventilation and hoist building. The personnel shaft is located within the hoist building. The shafts reach a depth of approximately 450 metres.
The completed sections of the ventilation and hoist buildings are included in the scope of the ONKALO research facility, and in the future, they will serve actual final disposal operations and the facilities built for the purpose. In future, access to the underground facilities will be from both the vehicle access tunnel and the personnel shaft.