"Making the site of a radioactive disaster truly secure can take generations."
by Henry Fountain. Photographs by William Daniels, The New York Times, 27 April 2014
Against the decaying skyline here, a one-of-a-kind engineering project is rising near the remains of the world’s worst civilian nuclear disaster.
An army of workers, shielded from radiation by thick concrete slabs, is constructing a huge arch, sheathed in acres of gleaming stainless steel and vast enough to cover the Statue of Liberty. The structure is so otherworldly it looks like it could have been dropped by aliens onto this Soviet-era industrial landscape.
If all goes as planned, by 2017 the 32,000-ton arch will be delicately pushed on Teflon pads to cover the ramshackle shelter that was built to entomb the radioactive remains of the reactor that exploded and burned here in April 1986. When its ends are closed, it will be able to contain any radioactive dust should the aging shelter collapse.
By all but eliminating the risk of additional atmospheric contamination, the arch will remove the lingering threat of even a limited reprise of those nightmarish days 28 years ago, when radioactive fallout poisoned the flatlands for miles around and turned villages into ghost towns, filled with the echoes of abandoned lives.
The arch will also allow the final stage of the Chernobyl cleanup to begin — an arduous task to remove the heavily contaminated reactor debris for permanent safe storage. That this job will fall from international hands to those of Ukraine presents new worries, especially as Russia threatens the nation’s borders.
For now, though, the rising arch is a sign of progress.
“It’s an amazing structure,” said Nicolas Caille, project director for Novarka, the consortium of French construction companies that is building it. “You can’t compare it to anything else.”
With nations debating the future of atomic power as one way to reduce greenhouse-gas emissions and fight climate change, the arch is also a stark reminder that nuclear energy, for all of its benefits, carries enormous risks. When things go wrong, huge challenges follow.
Containment and cleanup push engineering capabilities to their limits, as Japan is also finding out since the meltdowns at the Fukushima power plant three years ago.
The costs are enormous — the Chernobyl arch alone will end up costing about $1.5 billion, financed largely by the United States and about 30 other nations.
And making the site of a radioactive disaster truly secure can take generations.
Engineers have designed the Chernobyl arch to stand for 100 years; they figure that is how long it may take to fully clean the area. But there have always been questions about Ukraine’s long-term commitment, and the political turmoil and tensions with Russia have raised new concerns. So even a century might not be enough.
The arch, though, is a formidable structure, said Vince Novak, the director of nuclear safety for the European Bank for Reconstruction and Development, which administers the project’s financing. If necessary, he said, “it might be able to last 300 years or more.”
Like a Huge Dirty Bomb
THE CHERNOBYL ACCIDENT CAN BE LIKENED to a huge dirty bomb, an explosion that spewed radioactive material in all directions. The blast was followed by a fire that sent even more contaminants into the atmosphere that were then carried by winds across the region and into Western Europe.
In this way the disaster differs from nuclear power’s two other major accidents, at Three Mile Island in Pennsylvania in 1979 and Fukushima in 2011. At both of those plants, reactor cores melted down, but the core material — the nuclear fuel — remained within protective containment structures.
The four reactors at the Chernobyl plant had no such containment. But that was only one aspect of their flawed design. The system for controlling the nuclear fission reaction was temperamental, and under certain conditions reactor power could quickly soar out of control.
That is what happened in the early hours of April 26, 1986, at Chernobyl’s Unit 4, during an ill-advised test of some of the reactor’s safety systems. In a matter of seconds, the reactor power rose exponentially and the core was blasted apart by steam.
A few workers died immediately, but most of the technicians in Unit 4, and the firefighters who initially responded, suffered agonizing deaths over the ensuing weeks from exposure to high levels of radiation.
Officially, several dozen people were killed, and many others became sick. The radiation also caused thousands of later cancers — though just how many is still the subject of much debate.
INSIDE THE REACTOR
In the immediate aftermath, the Soviet authorities brought in the military to fight the reactor fire and evacuate nearby villages and the city of Pripyat, home to most of the plant workers and their families. Laborers were enlisted to hastily build the concrete-and-steel shelter, known as the sarcophagus. When their radiation exposure grew too high, the workers were replaced by others; in all, more than half a million people were involved in the initial cleanup.
That was nearly three decades ago. But in and around Chernobyl, it is as if the calendar froze.
An exclusion zone of about 1,000 square miles still exists around the plant, with access controlled through checkpoints. Although radiation levels have declined somewhat through the natural process of radioactive decay, the zone remains virtually empty. Many of the villages were bulldozed; forest has overtaken others. In Pripyat, where 45,000 people once lived, paint peels off the murals in the community center and a tree grows in the middle of a gym floor. In one apartment, all that remains is a smashed piano.
At Unit 4 itself, the dull gray sarcophagus has been shored up in recent years. It leaked almost from the day it was completed, and a small army of workers is still employed to maintain it and work in other areas of the sprawling plant. One of the tasks at Unit 4 involves pumping out rainwater that has become radioactive through contact with the reactor fuel inside the sarcophagus.
From time to time, new evidence of the disaster emerges.
“When we’ve excavated, we’ve found buried cranes, buried bulldozers,” said Laurin Dodd, an American who recently left Ukraine after serving as overall manager of the arch project. The equipment had become so radioactive during the initial cleanup that it had been simply buried in place.
The Human Toll
ON THE NIGHT OF THE ACCIDENT, Andrei Glukhov was at home, off from his job as a nuclear safety specialist at Chernobyl. When he heard the explosion he was not overly concerned — loud sounds occasionally came from the plant.
The next morning, he recalled, he telephoned the Unit 2 control room. A technician told him they were increasing power to make up for the loss of Unit 4. “What happened to Unit 4?” Mr. Glukhov asked. “Look out the window,” the man replied.
Mr. Glukhov, who lived with his wife and their two young children on the fifth floor of an apartment building, was less than two miles away, in Pripyat.
“I went to my balcony,” he recalled. “I saw smoke coming out of the plant.”
Telling his family to stay indoors, he left to offer help. Most of Pripyat’s residents received no such warning and went on with their day, oblivious to what was by then a severe radiation hazard. It was a Saturday; May Day celebrations were coming up in a few days. Near the city’s center a new amusement park, with a gleaming Ferris wheel and bumper cars, was ready to open.
On Sunday morning, the residents were told that there were problems at the plant, and that in a few hours they would be evacuated by bus. They were advised to bring just a few possessions, as they would be gone only a few days.
“The bus picked us up right here,” Mr. Glukhov, 55, said. He was standing in front of his old apartment building in Pripyat, on a street so overgrown it hardly seemed possible that it could have once accommodated a bus.
He and his family headed toward Kiev, 70 miles to the south. But Mr. Glukhov felt he had to keep helping at the plant; halfway to Kiev, he said goodbye to his family and hitched a ride back to Chernobyl.
He did not see his wife and children again for a month. Living at a scout camp in an uncontaminated area and then on repurposed cruise ships on the Dnieper River about 40 miles from Chernobyl, he spent the next three years working at the plant, helping to keep the other three reactors under control.
Some of the workers who died were his friends, including Leonid Toptunov, a young reactor operator who was in the Unit 4 control room that night. Mr. Toptunov languished for about three weeks in a Moscow hospital, his organs and tissues severely damaged by penetrating radiation. His portrait, with those of the other early victims, adorns a memorial in Slavutich, the city outside the contaminated area that was built to replace Pripyat.
Mr. Glukhov, who now helps manage the arch project, said he cannot forget the sight that greeted him when he got back to Chernobyl. He returned to the plant on Monday and worked an evening shift; leaving at midnight, he passed by Unit 4.
“I realized the scale of the disaster when I saw the open core, glowing,” he said. “I don’t wish anyone would ever see it.”
ARTUR KORNEYEV HAS SEEN the core, again and again.
Mr. Korneyev, 65, a radiation specialist and native of Kazakhstan, first came to Chernobyl shortly after the accident. He understands more than most people the extent of the radioactive mess that remains in what was Unit 4.
While the number of radioactive particles released during the explosion and subsequent fire was enormous, they came from only about five tons of the reactor fuel. Close to 200 tons of fuel — uranium and its highly radioactive fission byproducts — remain in the bowels of the destroyed building.
Mr. Korneyev’s job was to locate the fuel within the sarcophagus and determine radiation levels to limit the exposure of other workers.
“We were the trailblazers,” said Mr. Korneyev. “We were always on the front edge.”
These days Mr. Korneyev works in the project management unit, but because of his health — he has cataracts and other problems related to his heavy radiation exposure during his first three years — he is no longer allowed inside the plant. “Soviet radiation,” he joked, “is the best radiation in the world.”
During the accident, the heat was so intense that the fuel liquefied, melting concrete and other materials it came in contact with in the rubble of the explosion. The highly radioactive mixture — often resembling volcanic lava — poured through ducts and other openings into a warren of spaces below the reactor, hardening as it cooled. In some places the material resembles waterfalls frozen in place.
But there were pieces of solid fuel in the rubble as well, and when necessary, Mr. Korneyev said, he and members of his team moved them, despite the dangers of exposure. “Sometimes we’d use a shovel,” he said. “Sometimes we’d use our boots and just kick it aside.”
Mr. Korneyev was one of the first people to alert Western experts that the sarcophagus was in poor shape. Alarmed at the possibility of another large release of radioactivity, the Group of 7 nations agreed in 1995 to finance work to make Unit 4 safe. In return Ukraine, by then an independent nation, agreed to close the two Chernobyl reactors that were still operating; the last was shut in 2000.
The immediate task was to stabilize the sarcophagus. That project, said Mr. Novak, the European Bank’s nuclear safety director, “was an even bigger challenge than the arch if you take into account the environment in which the work had to be carried out.”
Until the arch is in place, the risk of collapse remains — a point brought home last year when a section of the roof over the turbine hall, next to the destroyed reactor, collapsed, resulting in a small release of radiation.
Finishing the arch, however, will require several hundred million dollars more from donor nations — an effort made more complicated by the Ukrainian crisis. It helps, Mr. Novak said, that the first half of the arch is complete. “We finally have something to show them,” he said.
FOR MR. CAILLE, the construction manager, the arch is a job like no other.
“What’s been the biggest challenge? Every single thing,” he said.
Keeping a steel structure standing for a century is normally a straightforward task, Mr. Caille said. It’s all about controlling rust.
“Painting,” he said. “The Eiffel Tower, for example, is painted every 15 years.”
But when the arch is in place over the ruined Unit 4 reactor, radiation levels will be high. There would be no safe way for workers to scrape and repaint the structure’s cladding or huge trusses. Left unprotected, the steel would rust and the structure would eventually fail.
So the design goes to great lengths to eliminate the risk. Both the exterior and interior are being sheathed in rustproof stainless steel. The arch trusses themselves are made from conventional steel, as are the 580,000 bolts that will hold the pieces together. But dehumidifiers will treat the air that will be circulated around them.
“The air will be dried,” Mr. Caille said. “So rust cannot happen.”
He was speaking underneath the first half of the arch, which is larger than most football stadiums, with a span of 800 feet and a length of 250 feet. The day before, the structure had been raised to 360 feet by 10 cable-gripping jacks mounted on towers. At more than 20 million pounds, it is one of the heaviest objects ever lifted.
HOW THE ARCH IS BEING BUILT (0:58) [See original article]
by Mika Gröndahl. Source: Novarka; Shelter Implementation Plan, Project Management Unit.
The first half has been pushed to one side to allow work on the second half in the same construction area. Then the two halves will be joined and the entire structure will be moved to its final position.
The unusual construction process was designed so that workers — from Ukraine, Turkey, Azerbaijan, Portugal, the Netherlands and about 15 other countries — could work under low radiation conditions, even though the site is just a few hundred yards from the destroyed reactor.
“It’s better to be as far from the sarcophagus as possible,” Mr. Caille said, noting that radiation levels drop with distance.
But the contractors also decontaminated the area by removing radioactive junk and debris, as well as the top layer of soil. They then poured concrete slabs over the entire area and erected a concrete wall to protect workers closest to the sarcophagus.
Radiation levels around the site are carefully mapped and arch workers have to stay within prescribed areas. Everyone wears dosimeters, detectors that would sound an alarm if there were a release from the sarcophagus and radiation levels increased. But otherwise the workers have normal schedules and wear regular work clothes.
Yet working there can be anything but normal. “When you arrive here for the first time, it’s quite emotional,” Mr. Caille said. “We have a lot of people who have been involved or were here when they had the accident. It’s still very, very present.”
The Final Cleanup
AFTER THE ARCH IS IN PLACE, Mr. Dodd said, the plan is for Ukraine to eventually begin removing the unstable structures and the remaining fuel. That will ensure that the radiation does not eventually reach groundwater, which would endanger the water supply for the three million people of Kiev. Ukraine also must build a repository for all the high-level waste it recovers.
It is unclear where the money for that work will come from — especially now with the country in turmoil. Officials with the Ukrainian Embassy in Washington did not respond when asked for comment.
But even if there is enough money, there are technical questions as to whether the work can be accomplished, and if so how long it will take.
At Three Mile Island, all the fuel remained inside the containment vessel, yet it took more than a decade to safely remove it, essentially by remote control. It will be a much more complex task to remove fuel and debris from Unit 4, which was ripped apart by the explosion and further destroyed by fire and by the efforts to fight it.
Mr. Korneyev, the radiation specialist who knows better than most the conditions in the sarcophagus, has enormous doubts about the long-term project. “There is not the technology available to access this fuel inside the unit,” he said. “It’s really difficult because the pathways are obstructed.”
Mr. Novak of the European bank said one possibility was that Ukraine could further stabilize the sarcophagus and the reactor remains and just leave them, protected by the arch for far longer than the 100 years for which it was designed.
But that is all in the future. The more immediate problem is completing the arch in an unstable political environment.
“I am very concerned how the current situation will affect this initiative,” Mr. Novak said.
Chernobyl, near Ukraine’s northern border, is far from the Crimea and other disputed territory. “Chernobyl and the exclusion zone remain calm, and our contractors continue their work,” Mr. Novak said, although Western experts were evacuated for a week in March.
The project has enough money to continue well into next year. But at some point in the next few months, there must be a “political decision” on additional financing, he said.
Even before the political upheaval, Mr. Novak said, there were concerns about having to ask donors to contribute more. “But the risk of leaving this whole program unfinished is a prospect which I don’t think anyone would want to contemplate,” he said.