This year has seen some massive engineering feats, from the Russky Bridge in Vladivostok, the world’s largest cable-stayed bridge, to the Bosphorus Tunnel, the world’s first sea tunnel linking Turkey to Europe, to the New Century Global Centre in Chengdu, the world’s biggest building.
Arguably trumping them all is the arch being constructed around the Chernobyl Nuclear Power Plant, which has been touted as one of the biggest engineering projects of all time.
The $2 billion New Safe Confinement (NSC) project stands 360 feet tall – high enough to house the Statue of Liberty. At 843 feet wide, it is big enough to accommodate three A380 airplanes with ample room to spare.
The dimensions of the giant steel arch were determined based on the need to operate equipment inside the new shelter and decommission the existing shelter. It will be held together by 680,000 bolts, while the ends of the structure will be sealed by vertical walls assembled around, but not supported by, the existing structures of the reactor building.
Designed to encase the nuclear fuel still buried inside the reactor, which exploded in 1986, the airtight structure will protect the environment from radioactive dust within. It will contain remote handling equipment that will enable engineers to eventually dismantle the remains of the reactor in 100 years.
The NSC project is being built in two sections away from the nuclear reactor itself, as radiation levels directly above the sarcophagus are too high to permit direct construction on site. Weighing more than 30,000 tonnes in total – the metal frame alone is 23,000 tonnes, which is nearly three times the weight of the Eiffel Tower – it will then be moved into position onto concrete foundations which are eight metres deep via the use of hydraulic jacks. This sliding operation will take a total of three days.
The engineering and construction team behind the project is a European partnership. The NOVARK group is an equal joint venture between VINCI Construction Grands Projets (lead contractor) and Bouygues Travaux Publics.
Work is being led by American Don Kelly, a nuclear industry veteran, who presides over more than 1,000 engineers and specialists from 24 nations around the world. He keeps a careful eye on his team with strict guidelines in place to ensure they don’t exceed the annual allowance of exposure to radiation.
Design and construction methods follow the ALARA (As Low As Reasonably Achievable) principle. During the study phase, ALARA examined a range of solutions to a specific problem to calculate the “committed dose budget” for each one. For certain types of work, especially in areas close to the sarcophagus (e.g., final foundation beams and control buildings), employees have worked behind concrete or lead screens.
Already around a decade behind schedule, engineers hope the project will finally be completed by the end of 2015, blaming the radioactive environment for work on the project moving so slowly to date.
“It’s not dangerous, it’s just very, very difficult,” site manager Philippe Casse told the BBC. “You have to organise everything to avoid the risk to people. But it is worth doing. I’m not just here to make a living, I’m here to make Chernobyl safe.”
The plan is to keep the shield in place until either the radiation threat decreases or the Ukrainian government finds a permanent storage facility for the 200 tonnes of uranium and one tonne of plutonium still confined within the ruins.