At the vast reservation known as the Hanford Site in south-central Washington state, much of the activity these days concerns its 212 million liters (56 million gallons) of radioactive sludge. From World War II through the Cold War, the site produced plutonium for more than 60,000 nuclear weapons, creating enough toxic by-products to fill 177 giant underground tanks. The U.S. Department of Energy (DOE), which controls Hanford, is pushing to start “vitrifying,” or glassifying, some of that waste within two years. The monumental undertaking is the nation’s—and possibly the world’s—largest environmental cleanup effort. It has been going on for decades and will take decades more to complete.
But the tanks are not the only outsize radioactive hazard at Hanford. The site also houses nearly 2,000 capsules of highly radioactive cesium and strontium. Each of the double-walled, stainless-steel capsules weighs 11 kilograms and is roughly the size of a rolled-up yoga mat. Together, they contain over a third of the total radioactivity at Hanford.
For decades, the capsules have resided in a two-story building called the Waste Encapsulation and Storage Facility (WESF). Inside, the capsules sit beneath 4 meters of cooling water in concrete cells lined with stainless steel. The water surrounding the capsules glows neon blue as the cesium and strontium decay, a phenomenon known as Cherenkov radiation.
Built in 1973, the facility is well beyond its 30-year design life. In 2013, nuclear specialists in neighboring Oregon warned that the concrete walls of the pools had lost structural integrity due to gamma radiation emitted by the capsules. Hanford is located just 56 kilometers (35 miles) from Oregon’s border and sits beside the Columbia River. After leaving the site, the river flows through Oregon farms and fisheries and eventually through Portland, the state’s biggest city.
In 2014, the DOE’s Office of the Inspector General concluded that the WESF poses the “greatest risk” for serious accident of any DOE facility that’s beyond its design life. In the event of a severe earthquake, for instance, the degraded basins would likely collapse, draining the cooling water. In a worst-case scenario, the capsules would then overheat and break, releasing radioactivity that would contaminate the ground and air and render parts of the Hanford Site inaccessible for years and potentially reach nearby cities.
“If it’s bad enough, it means all cleanup essentially stops,” says Dirk Dunning, an engineer and retired Hanford expert who worked for the Oregon Department of Energy and who helped flag initial concerns about the concrete. “We can’t fix it, we can’t stop it. It just becomes a horrible, intractable problem.”
To avoid such a catastrophe, in 2015 the DOE began taking steps to transfer capsules out of the basins and into dry casks on an outdoor storage pad. The plan is to place six capsules inside a cylindrical metal sleeve; air inside the cylinder is displaced with helium to dissipate heat from the capsules. The sleeves are then fitted inside a series of shielded canisters, like a nuclear nesting doll. The final vessel is a 3.3-meter-tall cylindrical cask made of a special steel alloy and reinforced concrete. A passive cooling system draws cool air into the cask and expels warm air, without the need for fans or pools of water. The cask will sit vertically on the concrete pad. Eventually, there will be 16 to 20 casks. Similar systems are used to store spent nuclear fuel at commercial power plants, including the Columbia Generating Station at Hanford. The agency has until 31 August 2025 to complete the work, according to a legal agreement between the DOE, the state of Washington, and the U.S. Environmental Protection Agency.
When the transfer is completed, DOE estimates the new facility will save more than US $6 million per year in operating costs. But it’s intended only as a temporary fix. After 50 years in dry storage—around 2075, in other words—the capsules’ contents could be vitrified as well, or else buried in an unspecified deep geologic repository.
Even that timeline may be too ambitious. At a congressional hearing in March, DOE officials said that treatment of the tank waste was the “highest priority” and sought to defer the capsule-transfer work and other cleanup efforts at Hanford. They also proposed slashing Hanford’s annual budget by $700 million in fiscal year 2021. The DOE Office of Environmental Management’s “strategic vision” for 2020–2030 [PDF] noted only that the agency “will continue to evaluate” the transfer of capsules currently stored at the WESF.
And the COVID-19 pandemic has further complicated the department’s plans. The DOE now says it “will be assessing potential impacts on all projects” resulting from reduced operations due to the pandemic. The department’s FY2021 budget proposal calls for “safely” deferring work on the WESF capsule transfers for one year, while supporting “continued maintenance, monitoring, and assessment activities at WESF,” according to a written response sent to IEEE Spectrum.
Unsurprisingly, community leaders and state policymakers oppose the potential slowdowns and budget cuts. They argue that Hanford’s cleanup—now over three decades in the making—cannot be delayed further. David Reeploeg of the Tri-City Development Council (TRIDEC) says the DOE’s strategic vision and proposed budget cuts add to the “collective frustration” at “this pattern of kicking the can down the road.” TRIDEC advocates for Hanford-related priorities in the adjacent communities of Richland, Kennewick, and Pasco, Wash. Reeploeg adds that congressional support over the years has been key to increasing Hanford cleanup funding beyond the DOE’s request levels.
How did Hanford end up with 1,936 capsules of radioactive waste?
The cesium and strontium inside the capsules were once part of the toxic mix stored in Hanford’s giant underground tanks. The heat given off by these elements as they decayed was causing the high-level radioactive waste to dangerously overheat to the point of boiling. And so from 1967 to 1985, technicians extracted the elements from the tanks and put them in capsules.
Initially, the DOE believed that such materials, especially cesium-137, could be put to useful work, in thermoelectric power supplies, to calibrate industrial instruments, or to extend the shelf life of pork, wheat, and spices (though consumers are generally wary of irradiated foods). The department leased hundreds of capsules to private companies around the United States.
One of those companies was Radiation Sterilizers, which used Hanford’s cesium capsules to sterilize medical supplies at its facilities in Decatur, Ga., and Westerville, Ohio. In 1988, a capsule in Decatur developed a pinhole leak, and 0.02 percent of its contents escaped—a mess that took the DOE four years and $47 million to clean up. Federal investigators concluded that moving the capsules in and out of water more than 7,000 times caused temperature changes that damaged the steel. Radiation Sterilizers had removed temperature-measuring systems in its facility, among other failures cited by the DOE. The company, though, blamed the government for shipping a damaged capsule. Whatever the cause, the DOE recalled all capsules and returned them to the WESF.
The WESF now contains 1,335 capsules of cesium, in the form of cesium chloride. Most of that waste consists of nonradioactive isotopes of cesium; of the radioactive isotopes, cesium-137 dominates, with lesser amounts of cesium-135. Another 601 capsules contain strontium, in the form of strontium fluoride, with the main radioactive isotope being strontium-90.
Cesium-137 and strontium-90 have half-lives of 30 years and 29 years, respectively—relatively short periods compared with the half-lives of other materials in the nation’s nuclear inventory, such as uranium and plutonium. However, the present radioactivity of the capsules “is so great” that it will take more than 800 years for the strontium capsules to decay enough to be classified as low-level waste, according to a 2003 report by the U.S. National Research Council. And while the radioactivity of the cesium-137 will diminish significantly after several hundred years, cesium-135 has a half-life of 2.3 million years, which means that the isotope will eventually become the dominant source of radioactivity in the cesium capsules, the report said.
Workers at Hanford continue to monitor the condition of the capsules by periodically shaking the containers using a long metal gripping tool. If they hear a “clunk,” it means the inner stainless-steel pipe is moving freely and is thus considered to be in good condition. Some capsules, though, fail the clunk test, which indicates the inner pipe is damaged, rusty, or swollen, and thus can’t move. About two dozen of the failed capsules have been “overpacked”—that is, sealed in a larger stainless-steel container and held separately.
Moving the capsules from wet storage to dry is only temporary
The DOE has made substantial progress on the capsule-transfer work in recent years. In August 2019, CH2M Hill Plateau Remediation Company, one of the main environmental cleanup contractors at Hanford, completed designs to modify the WESF for removal of the capsules. In the weeks before COVID-19 temporarily shut down the site in late March, crews had started fabricating equipment to load capsules into sleeves, transfer them into casks, and move them outside. A team cleaned and painted part of the WESF to make way for the loading crane. At the nearby Maintenance and Storage Facility, workers were building a mock-up system to allow people to train and test equipment.
During the lockdown, employees working remotely continued with technical and design reviews and nuclear-safety assessments. With Hanford now in a phased reopening, CH2M Hill workers recently broke ground on the site of the future dry cask storage pad and have resumed construction at the mock-up facility. Last October, the DOE awarded Intermech, a construction firm owned by Emcor, a nearly $5.6 million contract to build a reinforced-concrete pad surrounded by two chain-link fences, along with utility infrastructure and a heavy-duty road connecting the WESF to the pad.
However, plans for fiscal year 2021, which starts in October, are less certain. In its budget request to Congress in February, the DOE proposed shrinking Hanford’s annual cleanup budget from $2.5 billion to about $1.8 billion. Officials sought no funding for WESF modification and storage work, eliminating $11 million from the current budget. Meanwhile, the agency sought to boost funding for tank-waste vitrification from $15 million to $50 million. Under its legal agreements, the DOE is required to start glassifying Hanford’s low-activity waste by 2023.
Reeploeg of the Tri-City Development Council says the budget cuts, if approved, would make it harder for the capsule-transfer project to stay on track.
Along with vitrification, he told Spectrum, “we think WESF is a top priority, too. Considering that the potential consequences of an event there are so significant, we want those capsules out of the pool and into dry-cask storage as quickly as possible.”
Reeploeg said the failure of another aging Hanford facility should have been a wake-up call. In 2017, a tunnel that runs into the Plutonium Uranium Extraction Plant partially collapsed, exposing highly radioactive materials. Officials had been aware of the tunnel’s structural problems since the 1970s. Ultimately, no airborne radiation leaks were detected, and no workers were hurt. But in a February 2020 report, the Government Accountability Office said the DOE hadn’t done enough to prevent such an event.
Hanford experts at Washington state’s Department of Ecology said a short-term delay on the WESF mission won’t significantly increase the threat to the environment or workers.
“We don’t believe that there’s an immediate health risk from a slowdown of work,” says Alex Smith, the department’s nuclear waste program manager. So long as conditions are properly maintained in the pool cells, the capsules shouldn’t see any noticeable aging or decay in the near-term, she says, but it still makes sense to transfer the capsules to reduce the risk of a worst-case disaster.
In an email to Spectrum, the DOE noted that routine daily inspections of the WESF pool walls haven’t revealed any visible degradation or spalling—flaking that occurs due to moisture in the concrete.
Still, for Hanford watchdogs, the possibility of any new delays compounds the seemingly endless nature of the environmental cleanup mission. Ever since Hanford shuttered its last nuclear reactor in 1987, efforts to extract, treat, contain, and demolish radioactive waste and buildings have proceeded in fits and starts, marked by a few successes—such as the recent removal of 27 cubic meters of radioactive sludge near the Columbia River—but also budgeting issues, technical hurdles, and the occasional accident.
“There are all these competing [cleanup projects], but the clock is running on all of them,” says Dunning, the Oregon nuclear expert. “And you don’t know when it’s going to run out.”
It’s a place of superlatives. Reporters have called it the most polluted place in the Western Hemisphere. It’s also the location of one of the largest construction projects in the world.
At the Hanford Site in south-central Washington state, 177 giant tanks sit below the sandy soil, brimming with the radioactive remnants of 44 years of nuclear-materials production. From World War II through the Cold War, Hanford churned out plutonium for more than 60,000 nuclear weapons, including the atomic bomb that razed Nagasaki, Japan, in August 1945. The sprawling enterprise eventually contaminated the soil and groundwater and left behind 212 million liters of toxic waste—enough to fill 85 Olympic-size swimming pools. Decades after the site stopped producing plutonium, the U.S. government is still grappling with how to clean it all up.
Today the 1,500-square-kilometer site, roughly half the size of Rhode Island, is a quiet expanse of sagebrush and wispy grasses outside Richland, Wash. The underground steel-and-reinforced-concrete tanks are grouped in “farms” beneath a central plateau, while shuttered nuclear reactors stand like sentinels on the periphery. Scientists have identified some 1,800 contaminants inside the tanks, including plutonium, uranium, cesium, aluminum, iodine, and mercury. Watery liquids rest atop goop as thick as peanut butter and salt cakes resembling wet beach sand.
The waste is what’s left of an intense period in wartime and Cold War innovation. Starting in 1943, Hanford experts pioneered industrial-scale methods for chemically separating plutonium from irradiated uranium, and doing so safely. Their original bismuth-phosphate process yielded hockey-puck-size “buttons” of plutonium, which were then formed into spherical cores and used in the 1945 Trinity atomic bomb test in New Mexico and then the Nagasaki bomb. Over the years, five more processes followed, culminating with plutonium uranium extraction (PUREX), which became the global standard for processing nuclear fuels.
Each of these methods produced its own distinct waste streams, which were stored on-site and then pumped into underground storage tanks. When some of the older single-shell tanks started leaking years later, workers pumped the liquids into newer, sturdier double-shell tanks. Chemical reactions ensued as the different waste products mixed together, leaving each tank filled with its own complex aggregation of liquids, solids, and sludges.
The upshot is that by 1987, when Hanford stopped producing plutonium, the tank farms contained a deadly brew of chemicals, metals, and long-lasting radionuclides. No two of the 177 tanks contain exactly the same concoction, but they all pose a significant public risk. The site borders the Columbia River, which nourishes the region’s potato crops and vineyards, serves as a breeding ground for salmon, and provides drinking water for millions of people. So far, the aging, corroding vessels have leaked roughly 4 million liters. Some experts have said it’s only a matter of time before more waste seeps through the cracks.
The U.S. Department of Energy (DOE), which controls Hanford, has for decades had a goal of treating and “vitrifying,” or glassifying, the tank waste for safer disposal. Vitrification is a time-tested method for immobilizing radioactive waste by turning it into glass blocks. With the waste thus encased, the harmful radionuclides cannot leach into rivers or underground water tables. To enhance the isolation, the most radioactive blocks are put in steel containers, which can then be deposited in a dry and geologically stable underground vault. Vitrification plants have been built and successfully operated in Belgium, France, Germany, Japan, Russia, the United Kingdom, and the United States.
But Hanford’s waste is unique among the world’s nuclear leftovers, in both composition and volume. Before they can turn it into glass, workers must first figure out exactly what is inside each tank and then develop glassmaking formulas for each batch.
It is a monumental task, and it’s just one facet of one of the biggest engineering projects in the world. The centerpiece of the work is a series of vast facilities called the Waste Treatment and Immobilization Plant, also known as the Hanford Vit Plant, sprawled over some 25 hectares (65 acres). The DOE currently estimates that it will cost US $16.8 billion to finish the plant, which is being built by Bechtel National and a host of subcontractors. Even as scientists continue to puzzle over Hanford’s tank waste, and as contractors flip the lights on in shiny new buildings, concerns about massive cost overruns, contractor lapses, and missed deadlines weigh heavily on the project. Hanford, born and built feverishly in the heat of World War II, now seems to be in a slow, meandering slog toward an unseen finish line.
“Hanford is unique,” says Will Eaton, who leads the vitrification task force at the DOE’s Pacific Northwest National Laboratory (PNNL) in Richland. “There’s been lots of work done on the details, to make sure we have the highest likelihood of real, efficient success when we get going. Because it’s a long mission.” Eaton, who is 53 years old, adds, “My goal is that the plant actually starts up before I retire.”
I visited Hanford in July 2019 to get a better understanding of the many challenges facing the beleaguered vitrification project. I met Eaton on a blindingly sunny afternoon on the PNNL campus, which sits in an oasis of green trees amid the desert scrub. Hanford begins directly across the street, stretching out toward the flat ridge of Rattlesnake Mountain.
Eaton held up a clear plexiglass vessel, about 13 centimeters in diameter. In May 2018, his team used containers like this to glassify 11 liters of waste from two of the Hanford tanks. As a safety precaution, the experiment was conducted beneath a radioisotope fume hood. Those vessels contain the largest volume of Hanford waste that’s been vitrified so far, after three decades and billions of dollars. Just 211,999,989 more liters to go.
After I met with Eaton, I set off to visit Hanford. The DOE wasn’t letting individual journalists visit the Vit Plant, so I opted for the next best thing: I joined a public tour of the Hanford cleanup site. About a dozen passengers and I rode in an air-conditioned bus through the reservation, most of which resembles arid parkland. Tall bluffs stand off in the distance, carved by ancient rivers. Herds of elk sought shade among spindly trees near an abandoned schoolhouse.
It’s an incongruous but resonant sight. In 1943, as part of the Manhattan Project, the U.S. government seized a vast swath of land, including the towns of White Bluffs and Hanford, to build a nuclear manufacturing complex. The government ordered 1,500 homesteaders to leave their farms and towns, and Native American tribes were barred from visiting sacred fishing, hunting, and ceremonial grounds. To the west, members of the Wanapum tribe still live in a community that overlooks Hanford.
As the bus ascends the central plateau, sweeping vistas give way to rumbling forklifts, workers in hard hats, and buildings wrapped in scaffolding. Our tour guide notes that his great-nephew works here as a welder, a member of the 2,800-person construction crew.
The Vit Plant was born out of a comprehensive 1989 cleanup agreement among the DOE, the U.S. Environmental Protection Agency, and the state of Washington’s Department of Ecology. Construction began in 2002 and was supposed to wrap up by 2011, at a cost of $4.3 billion. But a series of major unforeseen problems soon cropped up, including dangerous hydrogen accumulation in piping and ancillary vessels, and inadequate ventilation for managing radon and other gases that are produced as the radioactive waste material breaks down. Cost estimates soared, and timelines stretched.
Today, the Vit Plant is a complex of buildings the size of a small town. Its 56 systems require an electric power grid that could light up 2,250 houses; a chilled-water system could supply air-conditioning to 23,500 houses. A 1.3-million-liter storage tank can hold enough diesel fuel to fill the tanks of 19,000 cars at once.
Even after the Vit Plant is completed, the actual cleanup will take decades more. In its 2019 Hanford Lifecycle Scope, Schedule and Cost Report [PDF], the DOE estimated that the process of vitrifying and disposing of Hanford’s waste could cost as much as $550 billion and last 60 years.
The plan calls for tank waste to flow via underground pipes to a massive pretreatment facility. This facility will eventually rise 12 stories, although during my tour it’s still just an outline of metal frames, above which hovers a motionless yellow crane. Inside sealed tanks, pulse-jet mixers, working like turkey basters, will suck up the waste and eject it at high velocity, to keep the whole tank mixed and prevent solid particles from settling. Ion exchangers will remove highly radioactive isotopes, dividing the waste stream into two groups. High-level radioactive waste makes up only about 10 percent of the total waste by volume but accounts for 90 percent of the radioactivity, Eaton says. The remaining waste is considered low-activity waste, containing very small amounts of radionuclides.
The appropriate streams will flow to separate high-level and low-activity vitrification facilities. In both, technicians will mix the waste with silica and other glass-forming materials and then pour the lot into a ceramic-lined melter. Immersed electrodes will heat the melter’s tank to nearly 1,150 °C, turning the mixture into a red-hot goop of molten glass. Low-activity waste will be poured into a container made of stainless steel, where it will cool and harden into a 2.3-meter-tall, 1.2-meter-diameter log. High-level waste will go into longer, skinnier 4.4-meter-tall, 0.6-meter-diameter canisters, also made of stainless steel.
Off-gases, including steam and nitrogen oxides, will exit through a nozzle in the melter’s roof, to be collected and treated to remove radioactive isotopes and keep pollutants out of the environment.
Up to 1,000 steel-encased logs of low-activity waste will be produced each year and then buried in nearby trenches. The Vit Plant complex also includes an analytical laboratory, which will test some 3,000 glass samples of low-activity waste each year, ensuring that the vitrified waste meets regulatory requirements.
Once completed, the high-level waste plant is slated to produce some 640 canisters per year. The vitrified high-level waste is considered too dangerous to keep on-site, even inside the steel canisters. Instead, that waste will be sent to an as-yet-unidentified off-site location. The original plan called for the high-level waste to be buried in a deep geologic repository such as the proposed and long-delayed Yucca Mountain site in Nevada. Construction on Yucca Mountain began in 1994 but was halted during the Obama administration amid fierce resistance from Nevada politicians, Native American groups, environmentalists, and others. President Trump, who called for the revival of the project early in his administration, recently reversed his stance on the matter. At present, there are no plans to build a deep repository anywhere in the United States.
Meanwhile, Hanford cleanup experts are figuring out ways to dramatically reduce the number of vitrified logs they’ll need to produce and store. When workers began building the Vit Plant 18 years ago, for instance, researchers were designing glasses that contained no more than 10 percent waste, the rest being materials necessary for glass forming. By modeling different formulas, a team at PNNL found they could double the waste portion to 20 percent, in part by finding ways to accommodate more aluminum, chromium, and other chemicals. That could halve the number of glass logs that Hanford has to produce and store.
As the tour bus winds its way through the Hanford Site, empty dirt patches mark the footprints of demolished buildings from the plutonium-production period. Their scraps are now interred in a massive landfill, which holds more than 16 million metric tons of low-level radioactive, hazardous, and mixed wastes. A Hanford employee on the bus points to black pipes snaking along the road; these carry contaminated groundwater away from the Columbia River and toward a central treatment plant, we’re told.
During Hanford’s plutonium-production heyday, workers discharged some 1.7 trillion liters of waste liquids into soil disposal sites, which developed into vast underground plumes of toxic chemicals, including the carcinogens hexavalent chromium and carbon tetrachloride [PDF], that infiltrated aquifers. Today six underground pump-and-treat systems hydraulically push contaminants toward the 200 West Groundwater Treatment Plant, a cavernous space filled with silver tubes and tall gray bioreactors. The plant’s operator, CH2M Hill (now part of Jacobs Engineering Group), says it treats some 7.6 billion liters of groundwater every year. In September 2019, workers removed the last of the highly radioactive sludge that was being stored in underwater containers near the river.
Our tour complete, the bus heads back down the dusty plateau, past taco trucks and wisecracking signs: “Got Sludge? Yes We Do!”
The construction is “essentially complete,” the DOE says, on the Vit Plant’s low-activity vitrification facility, analytical laboratory, and most of the smaller support buildings. But work on the pretreatment facility has been “deferred,” as Hanford experts try to resolve technical questions regarding the separation and processing of waste and the design life of the facility’s equipment. In late 2016, officials also decided to halt construction on the high-level vitrification facility so they could focus on treating the low-activity waste.
To make progress on the low-activity waste, the DOE’s latest strategy calls for bypassing the pretreatment facility. Instead, the liquid waste will be pumped into a smaller system, near the tanks where the waste is being stored. This system will filter out large solids and remove radioactive cesium, which has a relatively short half-life but emits high amounts of tissue-damaging gamma radiation and is thus considered the most immediately dangerous of the radionuclides in the waste. The liquid will then flow directly to the low-activity waste vitrification plant to be glassified. An effluent-management facility will handle the liquid waste produced by the glass melters and off-gas treatment system.
The DOE’s Office of River Protection, which oversees the tank cleanup mission, says it is on track to start processing low-activity waste this way as soon as 2022. As part of the preparations, in May 2019, Hanford workers began installing two towering, 145-metric-ton vessels that will hold effluent.
Last August, officials from the DOE and Bechtel National celebrated the opening of a 1,860-square-meter annex to the low-activity waste facility. The building houses the control room and operations center, where workers will perform startup and testing activities.
At the ribbon-cutting ceremony, the Vit Plant’s project director, Valerie McCain, said, “We are getting closer to making low-activity-waste glass.”
It’s anybody’s guess when Hanford will start vitrifying the high-level waste. The DOE says the technical issues that stalled construction have mostly been resolved but that it “cannot project with certainty” when the pretreatment and high-level waste vitrification facilities will be completed and put into service. The answer depends on many variables, including federal funding, the efficiency of contractors, and the pace of technological advances. In September, the department warned regulators in the state of Washington that it is at “serious” risk of missing deadlines to start treating high-level waste by 2033 and have the plant fully operational by 2036. The deadlines are specified in legal agreements among the DOE, the state of Washington, and other interested parties.
Meanwhile, the DOE is also studying alternative methods for treating some of the waste, including filling the tanks with a concrete-like grout, to in effect immobilize the waste in place. Officials had considered such a strategy earlier in the cleanup mission, but they ultimately ruled that vitrification was the safest, surest path for treatment.
Regulators as well as activists say they are frustrated to be revisiting the glass-versus-grout debate, particularly given how much work is still left on the Vit Plant. “It can be hard on folks to feel like they’re beating their heads against a wall and not actually accomplishing the stuff they set out to accomplish,” says Alex Smith, the nuclear waste program manager for Washington state’s Department of Ecology.
Adding to the sense of inertia is the somber fact that most people working on Hanford cleanup today won’t be alive to see the end results. A person in her 40s now would be a centenarian in 2078, the year the DOE expects to conclude its cleanup work.
“It’s easy to say, ‘Well, what do you care? You’re not going to be here when the consequences of this decision hit,’ ” Smith adds. “It’s really a challenge for our workforce, for the DOE workforce, and for people who have been working at Hanford for a long time.”
To keep people aware of the Hanford mission, Smith’s department is increasing community outreach, through social media and school talks. She says public awareness is key to ensuring lawmakers continue to fund the cleanup—even if most U.S. taxpayers have never even heard of it. The waste may be buried in Washington state, but it’s the product of federal actions meant to safeguard the entire country, through nuclear weapons production.
“We feel that this is a national cleanup,” agrees Susan Leckband, who chairs the Hanford Advisory Board. The board offers policy advice to the DOE and regulators, and it includes local experts, current and former Hanford workers, representatives from neighboring Oregon, and members of three tribal governments: Nez Perce Tribe, Yakama Nation, and the Confederated Tribes of the Umatilla Indian Reservation.
Leckband acknowledges that people outside of Washington state don’t necessarily share the board’s perspective. “They have their own problems,” she says. “I get that. There are not unlimited funds.” She worries about a growing push for “faster and less expensive” solutions to the cleanup mission, rather than a “better and more permanent” approach.
John Vienna, a materials scientist at Pacific Northwest National Laboratory, hands me a shiny rectangular glass slab. The rusty red and orange stripes are iron, he says, of which there’s an abundance in Hanford’s high-level waste. Vienna’s team analyzes myriad materials to observe how they behave in glass. Inside the lab, cross-sections of metal canisters reveal glasslike obsidian, made from simulants of high-level tank waste. Chunks as green as emeralds contain low-activity waste simulants.
Vienna explains that the contaminants don’t sit inside the glass, like beer swishing in a bottle. Rather, they become part of the “bottle” itself, atomically bound in place until the glass dissolves—which won’t be for “upwards of a million years,” he says. By then, the troubling radionuclides will all have decayed to relatively benign levels.
The two waste types are challenging to treat for different reasons. High-level waste contains higher levels of the “cold chemicals,” such as aluminum, that were used in the more inefficient stages of plutonium production and that don’t dissolve easily in glass. Low-activity waste is mostly made of sodium salts, which can make glass less durable. Glass formulations must account for these distinct complications.
Scientists at PNNL’s sprawling campus have worked on waste vitrification for more than half a century. In the 1970s, for example, the lab developed the technology for the ceramic melters at the heart of Hanford’s high-level waste and low-activity waste facilities. Other U.S. locations as well as sites in Japan and Europe have used the technology to glassify their nuclear waste. Glassification began in 1996 at the DOE’s Savannah River Site in South Carolina, the United States’ other plutonium-production site, where some 133 million liters of radioactive liquid waste were stored. To date, a little over half of the waste has been processed. At the West Valley Demonstration Project, near Buffalo, N.Y., the DOE vitrified all 2.3 million liters of waste before demolishing the facility.
Compared to Hanford, those sites had less waste, and it was far more uniform in composition. For West Valley, scientists spent years developing one general formula that could be used to treat all of the waste, says Vienna, who worked on that project and several others. Given the sheer volume and complexity of Hanford’s 212 million liters of tank waste, experts have to take a different approach.
Researchers at PNNL are creating computational models based on the behavior of actual tank waste, chemically similar simulants, and lab tests. Inside clear cabinets, they study how glass samples are affected by extremely high and low temperatures and by water, so that they can verify the glass will dissolve slowly enough to outlive the radioactive hazard. To understand the effects of time, they’ve examined the structures of ancient glasses, including a 2- to 4-million-year-old piece of Icelandic basalt glass and a 1,800-year-old bowl handle recovered from a shipwreck in the Adriatic Sea. The idea is that when the Vit Plant becomes operational, experts will be able to refine the glass compositions on the fly, right up until the mixtures hit the melter. Vienna’s group is responsible for the modeling that will enable Hanford to double the amount of waste per glass log, for instance.
“Part of what our group does is understand how we can push the limits,” says Charmayne Lonergan, a PNNL materials scientist. “As you start doing that, you start cutting back on the number of years that processing all the waste may take. You start cutting back on costs, time, labor, facilities, and resources.”
Meanwhile, the clock is ticking, and an air of uncertainty still surrounds the Vit Plant. The DOE is moving to reclassify some of the nation’s nuclear waste as less dangerous, which could allow it to sidestep vitrification for some of Hanford’s tank waste.
In particular, the department said in June 2019 that it was changing the way it interpreted the definition of “high-level radioactive waste” at Hanford, Savannah River, and the Idaho National Laboratory. Traditionally, any by-products that result from processing highly radioactive nuclear fuels have been considered high level and must be buried in deep geological repositories. All of Hanford’s waste (before pretreatment) falls into this category. The department wants to instead categorize waste based not on how it was produced but on its chemical composition.
Under the revised definition, waste from fuel processing could be considered “low-level radioactive waste” if it doesn’t exceed certain radioactive concentration limits. The limit for cesium-137, for instance, is 4,600 curies (or 1.7 x 1014 bequerels) per cubic meter.
Under the new interpretation, low-level waste wouldn’t necessarily have to move through Hanford’s pretreatment and vitrification facilities. Some of it could potentially be turned into a groutlike form and trucked to a private waste repository in Texas. In other cases, Hanford workers could pour grout directly into tanks, as was done with seven underground vessels at Savannah River.
Federal officials and other proponents of this strategy say these steps could dramatically cut the time and cost required to treat Hanford’s tank waste. PNNL and five other DOE national laboratories have voiced “strong support” for the technical merits of the new interpretation.
Paul M. Dabbar, the DOE’s Under Secretary for Science, told reporters that the department will “analyze each waste stream and manage it in accordance with Nuclear Regulatory Commission standards, with the goal of getting the lower-level waste out of these states without sacrificing public safety.” He said that each tank considered for classification as low-level waste would require an environmental study, under the National Environmental Policy Act.
But critics, including Washington governor Jay Inslee and the state’s Department of Ecology, say that reclassifying Hanford’s waste will jeopardize environmental safety and give the DOE unilateral control over the cleanup mission. In a letter to the DOE, leaders of the Yakama Nation expressed their concern that the changes would lead to more contamination at the site and “a lower standard of clean-up.”
This latest controversy highlights the constant calculations that officials, regulators, activists, and citizens must make in confronting Hanford’s toxic legacy. Policy changes designed to accelerate cleanup have to be weighed against the safety and well-being of people who won’t be born for tens of thousands of years. Waste treatment methods are viewed through the prism of limited, and often dwindling, congressional funding. Scientific results don’t exist in a vacuum—they are interpreted according to political motives, public opinions, and business interests.
Leckband, the Hanford Advisory Board chair, says it’s important to take the long view. “Our mantra is, we want the best cleanup possible—for the public, the people who are paying for it, the people who will be drinking the water, breathing the air, and eating the vegetables in the entire Pacific Northwest as well as the country,” Leckband says. “It needs to be done not just for us, but also for future generations.”
This article appears in the May 2020 print issue as “What to Do With 177 Giant Tanks of Radioactive Sludge.”
If you drive along the main northern road through South Australia with a good set of binoculars, you may soon be able to catch a glimpse of a strange, windowless jet, one that is about to embark on its maiden flight. It’s a prototype of the next big thing in aerial combat: a self-piloted warplane designed to work together with human-piloted aircraft.
The Royal Australian Air Force (RAAF) and Boeing Australia are building this fighterlike plane for possible operational use in the mid-2020s. Trials are set to start this year, and although the RAAF won’t confirm the exact location, the quiet electromagnetic environment, size, and remoteness of the Woomera Prohibited Area make it a likely candidate. Named for ancient Aboriginal spear throwers, Woomera spans an area bigger than North Korea, making it the largest weapons-testing range on the planet.
The autonomous plane, formally called the Airpower Teaming System but often known as “Loyal Wingman,” is 11 meters (38 feet) long and clean cut, with sharp angles offset by soft curves. The look is quietly aggressive.
Three prototypes will be built under a project first revealed by Boeing and the RAAF in February 2019. Those prototypes are not meant to meet predetermined specifications but rather to help aviators and engineers work out the future of air combat. This may be the first experiment to truly portend the end of the era of crewed warplanes.
“We want to explore the viability of an autonomous system and understand the challenges we’ll face,” says RAAF Air Commodore Darren Goldie.
Australia has chipped in US $27 million (AU $40 million), but the bulk of the cost is borne by Boeing, and the company will retain ownership of the three prototypes. Boeing says the project is the largest investment in uncrewed aircraft it’s ever made outside the United States, although a spokesperson would not give an exact figure.
The RAAF already operates a variety of advanced aircraft, such as Lockheed Martin F-35 jets, but these $100 million fighters are increasingly seen as too expensive to send into contested airspace. You don’t swat a fly with a gold mallet. The strategic purpose of the Wingman project is to explore whether comparatively cheap and expendable autonomous fighters could bulk up Australia’s air power. Sheer strength in numbers may prove handy in deterring other regional players, notably China, which are expanding their own fleets.
“Quantity has a quality of its own,” Goldie says.
The goal of the project is to put cost before capability, creating enough “combat mass” to overload enemy calculations. During operations, Loyal Wingman aircraft will act as extensions of the piloted aircraft they accompany. They could collect intelligence, jam enemy electronic systems, and possibly drop bombs or shoot down other planes.
“They could have a number of uses,” Goldie says. “An example might be a manned aircraft giving it a command to go out in advance to trigger enemy air defense systems—similar to that achieved by [U.S.-military] Miniature Air-Launched Decoys.”
The aircraft are also designed to operate as a swarm. Many of these autonomous fighters with cheap individual sensors, for example, could fly in a “distributed antenna” geometry, collectively creating a greater electromagnetic aperture than you could get with a single expensive sensor. Such a distributed antenna could also help the system resist jamming.
“This is a really big concept, because you’re giving the pilots in manned aircraft a bigger picture,” Boeing Australia director Shane Arnott says. These guidelines have created two opposing goals: On one hand, the Wingman must be stealthy, fast, and maneuverable, and with some level of autonomy. On the other, it must be cheap enough to be expendable.
The development of Wingman began with numerical simulations, as Boeing Australia and the RAAF applied computational fluid dynamics to calculate the aerodynamic properties of the plane. Physical prototypes were then built for testing in wind tunnels, designing electrical wiring, and the other stages of systems engineering. Measurements from sensors attached to a prototype were used to create and refine a “digital twin,” which Arnott describes as one of the most comprehensive Boeing has ever made. “That will become important as we upgrade the system, integrate new sensors, and come up with different approaches to help us with the certification phase,” Arnott says.
The physical result is a clean-sheet design with a custom exterior and a lot of off-the-shelf components inside. The composite exterior is designed to reflect radar as weakly as possible. Sharply angled surfaces, called chines, run from the nose to the air intakes on either side of the lower fuselage; chines then run further back from those intakes to the wings and to twin tail fins, which are slightly canted from the vertical.
This design avoids angles that might reflect radar signals straight back to the source, like a ball bouncing off the inside corner of a box. Instead, the design deflects them erratically. Payloads are hidden in the belly. Of course, if the goal is to trigger enemy air defense systems, such a plane could easily turn nonstealthy.
The design benefits from the absence of a pilot. There is no cockpit to break the line, nor a human who must be protected from the brain-draining forces of acceleration.
“The ability to remove the human means you’re fundamentally allowing a change in the design of the aircraft, particularly the pronounced forward part of the fuselage,” Goldie says. “Lowering the profile can lower the radar cross section and allow a widened flight envelope.”
The trade-off is cost. To keep it down, the Wingman uses what Boeing calls a “very light commercial jet engine” to achieve a range of about 3,700 km (2,300 miles), roughly the distance between Seville and Moscow. The internal sensors are derived from those miniaturized for commercial applications.
Additional savings have come from Boeing’s prior investments in automating its supply chains. The composite exterior is made using robotic manufacturing techniques first developed for commercial planes at Boeing’s aerostructures fabrication site in Melbourne, the company’s largest factory outside the United States.
The approach has yielded an aircraft that is cheaper, faster, and more agile than today’s drones. The most significant difference, however, is that the Wingman can make its own decisions. “Unmanned aircraft that are flown from the ground are just manned from a different part of the system. This is a different concept,” Goldie says. “There’s nobody physically telling the system to iteratively go up, left, right, or down. The aircraft could be told to fly to a position and do a particular role. Inherent in its design is an ability to achieve that reliably.”
Setting the exact parameters of the Loyal Wingman’s autonomy—which decisions will be made by the machine and which by a human—is the main challenge. If too much money is invested in perfecting the software, the Wingman could become too expensive; too little, however, may leave it incapable of carrying out the required operations.
The software itself has been developed using the digital twin, a simulation that has been digitally “flown” thousands of times. Boeing is also using 15 test-bed aircraft to “refine autonomous control algorithms, data fusion, object-detection systems, and collision-avoidance behaviors,” the company says on its website. These include five higher-performance test jets.
“We understand radar cross sections and g-force stress on an aircraft. We need to know more about the characteristics of the autonomy that underpins that, what it can achieve and how reliable it can be,” Goldie says.
“Say you have an autonomous aircraft flying in a fighter formation, and it suddenly starts jamming frequencies the other aircraft are using or [are] reliant upon,” he continues. “We can design the aircraft to not do those things, but how do we do that and keep costs down? That’s a challenge.”
Arnott also emphasizes the exploratory nature of the Loyal Wingman program. “Just as we’ve figured out what is ‘good enough’ for the airframe, we’re figuring out what level of autonomy is also ‘good enough,’ ” Arnott says. “That’s a big part of what this program is doing.”
The need to balance capability and cost also affects how the designers can protect the aircraft against enemy countermeasures. The Wingman’s stealth and maneuverability will make it harder to hit with antiaircraft missiles that rely on impact to destroy their targets, so the most plausible countermeasures are cybertechniques that hack the aircraft’s communications, perhaps to tell it to fly home, or electromagnetic methods that fry the airplane’s internal electronics.
Stealth protection can go only so far. And investing heavily in each aircraft’s defenses would raise costs. “How much do you build in resilience, or just accept this aircraft is not meant to be survivable?” Goldie says.
This year’s test flights should help engineers weigh trade-offs between resilience and cost. Those flights will also answer specific questions: Can the Wingman run low on fuel and decide to come home? Or can it decide to sacrifice itself to save a human pilot? And at the heart of it all is the fundamental question facing militaries the world over: Should air power be cheap and expendable or costly and capable?
Other countries have taken different approaches. The United Kingdom’s Royal Air Force has selected Boeing and several other contractors to produce design ideas for the Lightweight Affordable Novel Combat Aircraft program, with test flights planned in 2022. Boeing has also expressed interest in the U.S. Air Force’s similar Skyborg program, which uses the XQ-58 Valkyrie, a fighterlike drone made by Kratos, of San Diego.
China is also in the game. It has displayed the GJ-11 unmanned stealth combat aircraft and the GJ-2 reconnaissance and strike aircraft; the level of autonomy in these aircraft is not clear. China has also developed the LJ-1, a drone akin to the Loyal Wingman, which may also function as a cruise missile.
Military aerospace projects often have specific requirements that contractors must fulfill. The Loyal Wingman is instead trying to decide what the requirements themselves should be. “We are creating a market,” Arnott says.
The Australian project, in other words, is agnostic as to what role autonomous aircraft should play. It could result in an aircraft that is cheaper than the weapons that will shoot it down, meaning each lost Wingman is actually a net win. It could also result in an aircraft that can almost match a crewed fighter jet’s capabilities at half the cost.
This article appears in the January 2020 print issue as “A Robot Is My Wingman.”
A new nuclear weapons inspection technology could enhance inspectors’ ability to verify that a nuclear warhead has been dismantled without compromising state secrets behind the weapon’s design.
This new non-proliferation tool, its inventors argue, would greatly assist the often delicate dance of nuclear weapons inspectors—who want to know they haven’t been hoaxed but are also sensitive to a military’s fear that spies may have infiltrated their ranks.
While nuclear non-proliferation treaties have historically verified the dismantlement of weapons delivery systems like ICBMs and cruise missiles, there have in fact never been any verified dismantlements of nuclear warheads themselves (in part for the reasons described above).
Yet there are 13,000 nuclear warheads in the world, meaning the entire globe is still just a hair trigger away from apocalypse—even as we approach the thirtieth anniversary of the Berlin Wall’s collapse.
As UN Secretary-General Antonio Guterres told world leaders last month, “I worry that we are slipping back into bad habits that will once again hold the entire world hostage to the threat of nuclear annihilation.”
How, then, to verifiably dismantle a nuclear bomb?
A Q&A with ‘Eyes in the Sky’ author Arthur Holland Michel
A new type of aerial surveillance, enabled by rapid advances in imaging and computing technology, is quietly replacing traditional drone video cameras. Wide-area motion imaging (WAMI) aims to capture an entire city within a single image, giving operators a God-like view in which they can follow multiple incidents simultaneously, and track people or vehicles backward in time.
Arthur Holland Michel, founder and co-director of the Center for the Study of the Drone, a research institute at Bard College in New York, has written a new book about WAMI called Eyes in the Sky: The Secret Rise of Gorgon Stare and How It Will Watch Us All. This fascinating history details WAMI’s development by researchers at a national lab, its deployment by the US military, and its arrival as a crime-fighting tool—and possibly privacy nightmare—in the skies above America.
IEEE Spectrum talked with Michel prior to the publication of his book. What follows is transcript of that interview, lightly edited for clarity and length.
Vice Admiral Dave Kriete explains how the United States maintains its stockpile, and why the nation is developing new low-yield nuclear weapons
Earlier this year, at a sprawling complex in the Texas Panhandle, a new type of nuclear weapon began rolling off the production line and into the United States arsenal. The ballistic missile warheads are low-yield and relatively small, and they reflect a growing push by U.S. President Donald Trump’s administration to modernize the nation’s nuclear weapons program after decades of stagnation.
Vice Admiral Dave Kriete has played a key role in developing U.S. nuclear weapons policies. Since June 2018, he has served as deputy commander of U.S. Strategic Command, the military unit responsible for detecting and deterring nuclear, space, and cyber attacks against the United States and its allies. Kriete also helped craft the 2010 and 2018 Nuclear Posture Reviews—the Pentagon’s guiding document for U.S. nuclear policy, strategy, and capabilities.
Kriete, who is based in Omaha, Nebraska, spoke with Spectrum during a recent visit to New York City. He discussed plans for nuclear weapons modernization, and the challenges to achieving them. This conversation has been edited and condensed for clarity.
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