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30 years later, $1.6B mega-project finally puts Chernobyl to rest

The nuclear reactor at Chernobyl is now sealed off from the world, and should finally be safe for the foreseeable future. Why did it take so long?
By Graham Templeton
chernobyl new confinement head

If you thought Fukushima headlines were finally on their way out, think again. This past week, 30 years after the nuclear disaster at Chernobyl, Ukrainian authorities announced(Opens in a new window) the successful entombment of the damaged reactor -- again. The Chernobyl reactor (hereafter, Chernobyl) has of course been buried in concrete and steel this entire time, but it's also been 30 years since Russian authorities put that original "sarcophagus" into place. Even concrete and metal weather over decades, especially in the extreme conditions around the Chernobyl site. After all this time, mankind's worst nuclear disaster is still so dangerous that the world has to complete an international mega-project just to keep it safe.

And the project, called New Safe Confinement, certainly was mega. More than 40 governments pitched in to provide about $1.6 billion for its construction. Over 10,000 different people contributed to building the structure, which stands 354 feet tall and an astonishing 843 feet wide. That makes it significantly larger than even super-large aircraft hangars, and constructed from some of the heaviest building materials there are. It's got an incredible array of design features to hopefully give it a 100-year lifespan or more. In attendance at the completion ceremony, Ukrainian President Poroshenko called it(Opens in a new window) "the biggest moving construction that humanity has ever created."

New Safe Confinement during construction, in 2013. Credit: Tim Porter.New Safe Confinement during construction, in 2013. Credit:

Indeed, long-term exposure to the area around Chernobyl is so dangerous that it was quickly decided that as much of the construction as possible would need to be done off-site, with a minimum of assembly taking place at the reactor itself. Thirteen enormous steel arches were constructed and delivered to the site, where they were slid into place to create the frame of an enclosure large enough to house the Cathedral at Notre Dame, and contain one of the most toxic environments on Earth. The flat, vertical end caps are built separately, and form a seal with the original reactor enclosure, without being supported by it.

Actually, New Safe Confinement (NSC) has to contain not just the reactor, but the original containment structure as well. The aging sarcophagus was understandably built at a breakneck pace, reaching completion in only about six months, while NSC has been in some form of planning or construction for the better part of a decade. The original shelter is well on its way to breaking down, and at this point it's integrity comes mostly from the questionable strength of the reactor walls themselves; thus, the New Safe Confinement structure had to not only fit over the original sarcophagus, but do it with enough extra room to allow robots to deconstruct or reinforce the old tomb inside this new one. This includes "dismantling cranes" built into the interior of the new shelter.

The project is called New Safe Confinement for a reason, as opposed to Containment. Containment is the process of keeping radioactive gasses from escaping, and it's what most active reactors in the world need to do -- what Chernobyl itself catastrophically failed to do as a result of the 1986 explosions and eventual meltdown. Confinement, on the other hand, is about keeping solid radioactive samples like those at the heart of Chernobyl from reaching or affecting the outside world. It's built to withstand extreme weather, fire, earthquakes, and more, and to do so without losing confinement, for a century or even more.

Getting that kind of durability from a structure this big in these conditions for that long is not easy. For one, New Safe Confinement is one of the only buildings in the world to enclose enough air to have its own weather -- and in the cold of the Ukrainian winter, that could lead to moisture from the air condensing on the roof and, eventually, interior rainfall. To avoid this, NSC has a 40-foot gap between the interior wall of the arches and the steel exterior cladding. There is a constant airflow through this space, which is kept at a higher pressure and temperature than the air filling the main interior compartment. This prevents condensation from forming on the inside. The air is also circulated through desiccant dryers to lower the humidity below the level that will corrode carbon steel.

fukushima headJapanese cleanup crews have struggle even to see into the Fukushima reactor, let alone clean up the nuclear material within.

If this all sounds like it will take a fair amount of work to keep running, you're right. It's important to remember that Chernobyl is not being buried and forgotten, but made safe for the continuing process of dealing with the disaster it still represents to this day. According to(Opens in a new window) a Deputy Director from the Ukrainian agency administrating the project, "The point is... once the NSC is in place, we’re not dealing with an emergency situation any more. Things can be done in a calm, well-prepared and organized fashion."

For comparison, Fukushima is a different situation. Since it's in a wealthier nation, nearer to population centers, and newer overall, the Fukushima power station will probably not still be in a Chernobyl-like state 30 years after its destruction. Still, even there, progress has been slow(Opens in a new window). Robots are consistently fried by the intense radiation inside the reactor walls, so even advanced technology is having a hard time seeing the state of the core itself. In order to get the picture necessary to start creating a clean-up plan, scientists have been forced to turn to cosmically generated quantum particles -- it's that hard to deal with a damaged reactor core.

Decommissioning a nuclear reactor takes a long time, even when the reactor is shut down safely, according to its original life plan. In 30 or 40 years we might well live in a world where all energy is generated from renewable sources, and where we still have to invest in maintenance for old, partially decommissioned nuclear power plants. We will one day view these silent, burdensome reactors as our last responsibility in mitigating the damage of airborne carbon production -- and a reminder that powering the modern world wasn't always as easy as letting Elon Musk install super-panels on our roofs.

Now read: How does nuclear energy work?

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