Above- and below-ground tanks store contaminated water at the Fukushima Daiichi disaster site.

How Engineers Use Ground Freezing to Build Bigger, Safer, and Deeper

<div class="related"></div>
<p>
</p>
<p>
 The cleanup after the meltdown at the Fukushima Daiichi nuclear power plant has been anything but smooth. First there was the denial that things were really so bad, then crews discovered leaky tanks and holes in radiation barriers, and finally Tepco, the utility company which owns the plant, admitted that tens of thousands of gallons of groundwater were flowing through areas contaminated with radiation.
</p>
<p>
 But lately, there’s reason for hope—the ground surrounding the plant will be frozen, which if it works, will isolate the most contaminated areas from the steady seep of groundwater flowing toward the ocean. The ice wall will
 <a href="http://www.reuters.com/article/2013/09/03/us-japan-fukushima-idUSBRE98002520130903">
  cost over $300 million
 </a>
 and might take as long as two years to construct. It’s a scheme that sounds like it was ripped from the pages of a comic book, a half-cocked idea cooked up by an evil genius. But ground freezing isn’t as radical as it sounds. Engineers have been using the technique for over a century.
</p>
<p>
 The basic premise behind ground freezing is that soil—made up of bits of minerals and organic matter, water, and air—becomes stronger and less penetrable when its water freezes and expands. To freeze the ground, steel pipes are drilled down about one meter apart along the perimeter of the site. An interior pipe is then filled with chilled brine that circulates through a refrigeration unit. As the brine circulates, it removes heat from the ground, and cylinders of ice begin to form around the steel pipes. In eight weeks or less, the ice cylinders merge to form a wall of frozen earth.
</p>
<p>
 Once in place, an ice wall is typically maintained for months or years, but some have been kept in place for decades. Once a project is completed, the pipes usually remain in the ground. Thawing can take months.
</p>
<figure class="richtext-image full-width">
<img alt="123 Washington St" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/123-washington-st.width-990_z7wu1WG.jpg"/>
<figcaption>Liquid nitrogen boils and escapes as workers freeze ground around a future elevator shaft in New York City.
        
    </figcaption>
</figure>
<p>
 Today, engineers are using ice walls to complete ever more daring projects. Some, like the proposed installation at Fukushima, keep harmful contaminants from escaping, while others prevent deep mines from collapsing. But some of the most breathtaking uses of ground freezing may have happened right in your backyard. They allowed workers to tunnel new underground routes for cars and trains while you went about your daily life, oblivious to the engineering magic that was going on below.
</p>
<div class="ad"></div>
<h2>
 Freeze Ray
</h2>
<p>
 Civil engineers don’t call it an ice wall, though. Rather, they refer to it by less dramatic names—artificial ground freezing or the Poetsch process, after its inventor, German engineer F. H. Poetsch, who developed the process to combat water in Belgian coal mines. Praised for its novelty in the late 1800s, the process remains mostly unchanged today. “This method of shaft-sinking…by means of the artificial production of low temperatures,” wrote Charles E. Greene in a letter to
 <i>
  Science
 </i>
 in 1885, “is an illustration of the new and unexpected directions in which chemical and physical processes become of use.”
</p>
<p>
 Greene predicted that this new method would enable startling feats of engineering, and he was right. More than 100 years later, Poetsch’s artificial ground freezing is used in civil engineering projects around the world, often with little fanfare. Now, after the news from Fukushima Daiichi, ground freezing has become something of a minor public obsession. In fact, so many people have been asking Masaru Mizoguchi, a soil scientist at the University of Tokyo, about ice walls that he now directs them to a video he posted to YouTube showing what happens when water comes into contact with frozen soil.
</p>
<div>
<iframe allow="autoplay; encrypted-media" allowfullscreen="" frameborder="0" height="270" src="https://www.youtube.com/embed/KnGQZGUb_Yc?feature=oembed" width="480"></iframe>
</div>
<p>
 The video illustrates the concept fantastically well. Mizoguchi has four plastic cups filled with sand. The sand in two of the cups is wet and frozen. In the others it’s dry. When he dumps water into the cups, it passes through the dry sand quickly, almost as if there was nothing in the cup. But when he dumps water on the frozen sand, it barely trickles out the bottom.
</p>
<p>
 “Normal soil is composed of soil particles and water and air,” Mizoguchi tells me. The amount space between soil particles, known as its porosity, determines whether or not groundwater is allowed to pass through, he says. But when the water part of the soil is frozen, it expands to fill the open spaces, locking the soil bits in place, and the frozen ground becomes an impenetrable barrier to moving water. A groundwater barrier, like the kind to be used in Fukushima, is usually two or three meters thick, says Joseph Sopko, director of ground freezing for New Jersey-based engineering firm Moretrench. For mines and other sites where the frozen ground must act as a structural support, the wall can be more than ten meters thick.
</p>
<p>
 Though the basic theory remains largely unchanged, computers have allowed engineers to construct more elaborate systems. This allows engineers like Sopko, who helped bring ground freezing into the computer age as a graduate student at Michigan State in the 1980s, to plan ground freezing projects in three dimensions.
</p>
<div class="newsletter"></div>
<h2>
 Bigger Digging
</h2>
<p>
 Such advances would later help one of Sopko’s colleagues at Moretrench, David Mueller, during ground freezing operations for Boston’s Big Dig, an enormous infrastructure project that buried Interstate 93, an elevated eyesore which cut the city in half. The Big Dig was conceived in the 1970s and planning began in the early 1980s. Ground was broken in 1991. The final cost, including interest on borrowed funds, exceeded $24 billion.
</p>
<p>
 While the Big Dig is infamous for its long timeline and inflated cost, there were a few bright spots, including the ground freezing operations. Engineers froze heaping portions of Boston’s soil solid. Mueller says Big Dig contractors chose artificial ground freezing because it offered the best way to excavate without risking subsidence, or a gradual shifting of the ground. It also minimized disruptions. Even as a 3.5 mile tunnel was carved through the heart of Boston, cars, buses, and trains continued to move along the roads and rails overhead.
</p>
<div class="pullquote">
<p>
 “The design had to be absolutely right.”
</p>
</div>
<p>
 “The real challenge on that particular project was working in and around all the Amtrak trains and their infrastructure. We had to install the system from within the tracks,” Mueller says. The complexity and scale of the Big Dig made it one of the—if not
 <i>
  the
 </i>
 —largest artificial ground freezing projects ever attempted in the U.S., he adds. “The design had to be right. The top of the tunnel was something like 10 feet below where the trains were.” That gave them enough ground to support the tracks above, but there wasn’t much room for error. “The design had to be absolutely right.”
</p>
<p>
 A few hundred miles southwest, in New York City, engineers employed ground freezing on a smaller but similarly audacious project. The East Side Access, which is expected to be completed in 2018, will finally bring the Long Island Railroad to Grand Central Station in Manhattan. After zipping along Long Island, the trains will submerge to travel beneath the country’s busiest rail intersection, below the East River, and under some of the most expensive real estate in the world.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/east-side-access-2.width-990_VduN0BZ.jpg"/>
<figcaption>The tunnel under Northern Boulevard isn't long, but it was one of the most challenging parts of the East Side Access project. As work continued below, ice formed around the tunnel arch.
        
    </figcaption>
</figure>
<p>
 Every part of the project presented engineers with a different challenge, but perhaps the most vexing was the tunnel beneath Northern Boulevard in Queens. It was only 100 feet long, but it had to be built beneath a five-track subway, the four-lane Northern Boulevard, and a three-track elevated railway. The importance of the infrastructure above and the instability of the soil made ground freezing a no-brainer. “This is really soft ground,” says Michael Horodniceanu, president of MTA Capital Construction.
</p>
<p>
 The top of the tunnel would be just 10 feet below the bottom of the subway tunnel. Ground freezing pipes were laid horizontally and uncomfortably close to the subway’s support piles. The proximity meant that engineers had to be aware not only of where they froze, but how the frozen soil would behave. Because the density of ice is lower than the density of liquid water, as soil freezes, it expands or swells. That expansion can cause cracks and create large, air-filled spaces. If this happens, the functionality of the frozen soil could be lost.
</p>
<p>
 “During the freeze periods, we were very careful not to have to much heaving. When water freezes, it expands, and there’s a rail above,” Horodniceanu says. Avoiding complications meant testing and modeling the characteristics of the soil long before freezing began. “We knew the limits, and we were constantly making sure that we stayed below the limits,” Horodniceanu says. “It sounds exotic, but this is done every day.”
</p>
<h2>
 In the Long Run
</h2>
<p>
 At Fukushima, experts agree that the actual system won’t be all that exotic, either. The biggest challenge will be ensuring the safety of the workers who will install the expansive system of pipes and coolant needed to create a frozen barrier. “We don’t see anything from a technical standpoint that would preclude ground freezing from being used as a barrier. It seems like an appropriate use,” Mueller says. Rather, it’s the site’s dangerous radiation levels that could complicate matters, he adds.
</p>
<p>
 For Fukushima, ground freezing isn’t a long-term solution, experts caution. Maintaining the barrier will require constant refrigeration, which requires a continuous source of power. Any interruption could compromise the barrier. Furthermore, powering the refrigeration units over a long period of time can be expensive. And in the case of Fukushima, it only contains the contamination—it doesn’t eliminate it. “I think it’s an appropriate thing to do. It is a smart thing to do,” Horodniceanu says. “But at the same time, the polluted water has to be extracted from the clean water.”
</p>
<figure class="richtext-image full-width">
<img alt="Providence CSO Raise Bore Shaft" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/providence-cso-raise-bore-shaft.width-990_BO8jny8.jpg"/>
<figcaption>Ground freezing keeps this shaft stable as work continues below on a sewer overflow project in Providence, Rhode Island.
        
    </figcaption>
</figure>
<p>
 The Japanese government is currently studying the frozen ground barrier proposal, and they expect to have a ground freezing system in place by April 2014, according to
 <a href="http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20130904_01b.pdf">
  a document
 </a>
 released in September by Japan’s Ministry of Economy, Trade and Industry. The proposed installation would encircle the four damaged reactors with an ice wall nearly one mile long and up to 100 feet deep, statistics that sound impressive but are quite achievable, Sopko points out. “It’s not a very challenging job, as far as depth goes,” he says. “The challenge is the men that have to drill the holes—keeping them safe, keeping them protected.”
</p>
<p>
 Today, even this project seems normal to Sopko, but while in graduate school, he wouldn’t have predicted that ground freezing would be used to contain nuclear contamination. But after years of designing and creating ice walls, he now thinks that it could be used for “just about anything.” The current challenge, he says, isn’t about getting bigger. “I think we can handle the large projects, honestly.” Instead, he and others are hoping to shrink the process. “We’re looking at making smaller plants right now, and using it on smaller applications. How do we do a smaller job with less energy and more efficient freeze plants?” When that happens, ground freezing could really heat up.
</p>
<p>
 Photo credits:
 <a href="http://www.flickr.com/photos/iaea_imagebank/8656859377/">
  Greg Webb/IAEA
 </a>
 , Moretrench, and
 <a href="http://www.flickr.com/photos/mtaphotos/8310696617/">
  MTAphotos/Flickr (CC-BY)
 </a>
</p>

<p>Artificial ground freezing is enabling engineers to complete ever more daring projects.</p>

Remotely-operated equipment loads highly-radioactive waste into holes bored in the walls.

A Salty Solution for Nuclear Waste

<p>
 Our caravan of SUVs pulls into a parking lot in the middle of four square miles of scruffy, unassuming brown desert 26 miles outside Carlsbad, New Mexico. Through the front window, I can see a row of semi-trailers loaded with drab, hulking metal and concrete casks. As I step out, the sun beats down on me with unrelenting intensity, despite the air’s slight spring chill. Above, jets streak across the cloudless, blue sky. Below, the ground conceals a national legacy, though it’s not the kind we tend to brag about. Entombed in a labyrinth of tunnels that wend their way through a 250-million-year-old salt deposit are decades of radioactive waste.
</p>
<p>
 This is the only working underground nuclear waste repository in the United States. It’s failing structurally—flowing under pressure, as every salt mine does—and I’m about to go inside.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/wipp4.width-990_DbFmBOw.jpg"/>
<figcaption>The Waste Isolation Pilot Plant holds decades of nuclear waste.
        
    </figcaption>
</figure>
<p>
 Hardhats, headlamps, and emergency respirators secured, my tour group of college students and professors is ready for the journey below. Just before we depart, we’re given collection bags so we can snag some Permian-age salt souvenirs. We’re told that the luckiest among us will collect pieces containing ancient water droplets trapped inside air bubbles in the salt. But first we’ll need to cram into the cage-like elevator that will lower us 2,150 feet down into the mine where salt walls are slowly sealing the nuclear waste entombed within.
</p>
<div class="related"></div>
<h2>
 One Working Solution
</h2>
<p>
 The Waste Isolation Pilot Plant, known locally as WIPP (pronounced “whip”), opened in 1999 after decades of back and forth between state and federal regulators. Today, it holds more than 85,000 cubic meters of radioactive waste arriving from as far away as South Carolina. Currently, WIPP is only authorized to handle waste containing elements with atomic numbers higher than 92—primarily plutonium—that originated from the development and manufacture of nuclear weapons. Between 1944 and 1988, the U.S. produced about 100 metric tons of plutonium, most of which was used to develop nuclear weapons.
</p>
<p>
 “We are disposing of long-lived materials here, not short-lived materials,” says Ned Elkins, WIPP program manager for Los Alamos National Laboratory, referring to the half-lives of the radioactive elements in the materials. Waste received from plutonium production facilities might include contaminated equipment, pipes or shielding, and other materials used in cleaning up or decommissioning weapons facilities.
</p>
<p>
 WIPP’s operators stack waste containers in rooms dug into the salt formation and then let geology do the rest. Under pressure from the ground above, salt formations flow into cracks and open spaces. Over several dozen years, salt will settle around the containers, forming a rocky seal. That self-sealing ability also protects the site from cracks caused by earthquakes—any that open will quickly close. So far, the site has been successful in containing radiation from the waste. A monitoring center in nearby Carlsbad sensed radioactive iodine in the atmosphere in 2011, but it wasn’t from WIPP—it was from the Fukushima disaster halfway around the globe.
</p>
<p>
 While WIPP has been accepting nuclear waste from weapons programs, no central repository currently exists in the U.S. for spent nuclear fuel and related waste from commercial reactors. Until one opens, waste has been sitting in interim storage at or near each of the nation’s 65 nuclear power plants. At the end of 2011, these sites and others held more than 67,000 metric tons of spent nuclear fuel,
 <a href="http://www.fas.org/sgp/crs/misc/R42513.pdf">
  according to a report
 </a>
 issued by the Congressional Research Service.
</p>
<div class="pullquote">
<p>
 “We did not design WIPP to stay open.”
</p>
</div>
<p>
 For decades, politicians, regulators, and scientists have been pitching, probing, and testing a ridge in the Nevada desert known as Yucca Mountain, hoping that it might be a suitable burying ground for our stockpiles of waste. But in 2009, the Obama administration moved to shelve the project by defunding it, citing concerns about the site’s safety. As the controversy over Yucca Mountain simmers, eyes are turning to the working repository I’m about to enter here in the New Mexican desert. WIPP might be the nuclear waste solution we’ve been looking for. And here’s the kicker, the residents of New Mexico are generally happy about it.
</p>
<p>
 Unlike Yucca Mountain, which was selected for the area’s stable geology, the mine’s eventual structural failure is welcomed. “We did not design WIPP to stay open,” Elkins says. “Our design is centered around accentuating and speeding the process of closure, encapsulation, and re-annealing,” he adds.
</p>
<div class="ad"></div>
<p>
 Proponents of a centralized repository for nuclear waste argue that storing waste in multiple sites across the country has myriad problems, from the potential for proliferation to widespread environmental contamination. A central location may also require less security than numerous sites dispersed across the U.S., making it cheaper to operate than many distributed sites. Though Yucca Mountain may be a dead end, there’s room for expansion at WIPP, Elkins says. Other opportunities could open up, too—New Mexico is home to other suitable salt formations.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/wipp2_3.width-990_Jr0HiU6.jpg"/>
<figcaption>Waste arrives at WIPP from all over the country on board trailers, which are visible near the facility's entrance.
        
    </figcaption>
</figure>
<p>
 The Department of Energy’s (DOE) Office of Nuclear Energy is again expected to take up the task of evaluating a variety of underground options for waste isolation and management,
 <a href="http://energy.gov/sites/prod/files/Strategy%20for%20the%20Management%20and%20Disposal%20of%20Used%20Nuclear%20Fuel%20and%20High%20Level%20Radioactive%20Waste.pdf">
  according to a report
 </a>
 released in January. These will likely include salt, clay, and granite. With WIPP’s success, salt could be a frontrunner, says Abraham Van Luik, senior scientist and director of international programs for the DOE Carlsbad Field Office.
</p>
<p>
 In April, four U.S. senators released a
 <a href="http://www.energy.senate.gov/public/index.cfm/files/serve?File_id=4f51d98f-c07a-4bdd-8460-a19e86b2b454">
  discussion draft of a bill
 </a>
 that would create a new government organization—the Nuclear Waste Administration—to deal specifically with the disposal of nuclear waste, a responsibility that currently falls within the Department of Energy. The draft received more than 2,500 public comments, and in late June, an updated version was sent to the Senate Committee on Energy and Natural Resources as the Nuclear Waste Administration Act of 2013.
</p>
<div class="pullquote">
<p>
 The people of Carlsbad asked for our nation’s nuclear waste back in the 1960s.
</p>
</div>
<p>
 In July, the committee heard testimony from Energy Secretary Ernest Moniz and a number of others, including representatives for state legislators, utilities, and environmental and science advocacy groups. Most agreed that advancing nuclear waste policy was a good thing, but hammering out the details will take some time.
</p>
<p>
 Based on
 <a href="http://cybercemetery.unt.edu/archive/brc/20120620220235/http://brc.gov/sites/default/files/documents/brc_finalreport_jan2012.pdf">
  the recommendations
 </a>
 of the Blue Ribbon Commission on America’s Nuclear Future released early last year, the Nuclear Waste Administration would need to obtain consent from surrounding communities when selecting disposal sites, a move intended to cultivate goodwill.
</p>
<p>
 While Yucca Mountain has been riddled with controversy, the people of Carlsbad
 <a href="http://www.cityofcarlsbadnm.com/AboutCarlsbad.cfm">
  asked for our nation’s nuclear waste
 </a>
 back in the 1960s. Since then, the local economy has benefitted from the planning, construction, and maintenance of WIPP,
 <a href="http://pearce.house.gov/press-release/congressman-pearce-introduces-legislation-protect-wipp">
  according to a statement
 </a>
 released by Representative Steve Pearce earlier this year. In May, Pearce introduced a bill to broaden the scope of WIPP to include government owned, non-defense waste. The list does not include uranium, though, the most common nuclear fuel used in the U.S. The bill is currently under consideration by energy and armed services subcommittees.
</p>
<p>
 Even with New Mexico vying to take on more waste, an operating repository for commercial waste could be as far away as 2048, according to the proposed plan. Meanwhile, nuclear waste from power plants keeps piling up. The amount of spent fuel in temporary storage is expected to grow by roughly 2,200 tons each year, more than doubling the current amount.
</p>
<p>
 Van Luik, who has built a career out of studying radioactive waste systems, spent 22 years working on Yucca Mountain before the program was halted. He now serves as a liaison for international collaboration on nuclear waste management, and he says the U.S. is falling behind. But he’s still optimistic.
</p>
<h2>
 Walking into WIPP
</h2>
<p>
 After a six-minute ride in a dark mine shaft elevator, I walk into a hazy, gray underground laboratory—WIPP is a test facility, after all. From the front seat of an electric cart, I can see that the walls carved in the salt are much smoother than I expected. As we move through a series of air-lock chambers deeper into the mine, our guide’s voice booms through the corridor. Looking up at the bulging ceiling, I’m suddenly reminded that 2,150 feet is a long way down.
</p>
<figure class="richtext-image full-width">
<img alt="WIPP Panel 7" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/wipp-panel-7.width-990_PiYfdyH.jpg"/>
<figcaption>A recently constructed corridor in Panel 7
        
    </figcaption>
</figure>
<p>
 According to the current plan, WIPP will eventually consist of eight large, excavated areas, known as panels, which are further divided into seven disposal rooms. The first five panels are already full, the sixth is currently being filled, and construction on the seventh was recently completed. The eighth panel will come later. We’re heading to Panel 6, where the action is.
</p>
<p>
 Behind the immediately recognizable yellow and red radiological hazard signs, I can just make out ordinary-looking canisters and boxes in the disposal room’s darkness. They contain relatively safe waste, the kind you can snap a group photo with. The truly dangerous stuff that needs more shielding is kept in holes bored into the room’s walls and is handled remotely.
</p>
<p>
 From a distance, the walls appear smooth, but up close they are rough and brittle. When I pry at them, salt chips away easily. Golf ball sized chunks of the stuff—gray, white, pink, and yellow—litter the halls along the margins. From this perspective, it’s easy to envision how the walls are slowly closing in on us. Nothing illustrates that better than the story of Panel 1. In the 10 years that passed between when the first disposal area was excavated and when waste first entered, Panel 1 closed to the point where it could only be partially filled. Having learned from that experience, operators now begin excavations only when waste is ready and available to fill a room. It’s what Elkins calls “just-in-time” mining.
</p>
<p>
 WIPP feels like it’s in constant motion—the continuous care needed to control the salt, the movement of the electric carts within the mine’s pathways, the loading of waste first into the walls and then the room, back to front. It all serves as a reminder that the place really is moving, just at a slower, inexorable pace. WIPP depends “on salt and the behavior of salt,” Elkins says. Salt flows under pressure, and it’s under a great deal of pressure this far underground. On a geologic time scale, it presses down with surprising speed, crushing and then encapsulating whatever is placed inside.
</p>
<p>
 The motion that makes WIPP so valuable can also make it a daunting place to work. All that’s separating miners from collapsed tunnels are wire nets, bolts, and a series of closely monitored sensors attached to the walls and ceiling. A catastrophic collapse has never happened, but every salt surface in the mine is closing in by 2-3 inches per year. Just to keep the tunnels passable, floors are re-cut every eighteen months to maintain enough headroom.
</p>
<p>
 The entire operation is balanced on a knife’s edge. “This repository can only operate as fast as we receive waste. Generally what limits, or what defines how long it takes [to fill a room], is not what we can do here but how fast sites are sending waste here,” Elkins says. “If we’re receiving waste at a rate that is consistent with what we can do, one of these rooms is about a month to a month and a half of work to fill.” But under normal working conditions, an entire panel might take as long as two years to fill.
</p>
<h2>
 Pressure to Solve the Problem
</h2>
<p>
 With Yucca Mountain now shelved, could salt be the answer for the United States? Van Luik, who has watched the rest of the world move ahead on waste burial, says yes. The first deep geological repositories for high-level waste and spent nuclear fuel are expected to begin operation in Europe between 2020 and 2025. In Finland, a site is being mined in granite. Later sites will be dug in clay in France and granite in Sweden. Germany has three salt repositories for nuclear waste, although two are now closed and a third was recently under investigation for safety reasons.
</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/wipp2_1.width-990_FJPSkjy.jpg"/>
<figcaption>Nuclear waste is placed in disposal rooms that are carved into the salt. In front, signs warn of the presence of radioactive material.
        
    </figcaption>
</figure>
<p>
 “Back in the 1980s, one of the three sites that was supposed to be characterized for a repository was in the Texas panhandle in a bedded salt formation,” Van Luik says. “Germany just completed 10 years of testing in a salt dome…and we’re very grateful to them for sharing their results. We learn from them,” he adds. “We make sure that we don’t repeat mistakes.”
</p>
<p>
 Beyond the salt formations in Texas and at WIPP in New Mexico, there are also large salt domes and bedded deposits in Louisiana, Michigan, and Mississippi. But as we learned from Yucca Mountain, location and attitude are everything, and picking a final resting place for our nuclear waste is wrought with fear and loathing.
</p>
<p>
 “It looks like some people in Congress—on both sides of the aisle—are really anxious to get this country moving forward again,” Van Luik says. “I think that this country will start to awaken to the fact that other countries are moving forward where we have been stymied by our own fears.”
</p>
<div class="newsletter"></div>
<p>
 Photos by Jessica Morrison, Sandia National Laboratory, and the U.S. Department of Energy
</p>

<p>Nuclear waste is piling up at reactors around the country, but there&#x27;s a remarkable substance we can safely bury it in.</p>

Jessica Morrison

Articles

How Engineers Use Ground Freezing to Build Bigger, Safer, and Deeper

A Salty Solution for Nuclear Waste

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