The nuclear enterprise comes together to conduct crucial experiments.
“You’ll travel 965 feet below ground at a rate of 880 feet per minute.”
Vince Gomes, a facilities manager at the Nevada National Security Site (NNSS), gestures toward a steel cage that transports scientists, miners, construction workers, and equipment from the Earth’s surface to a massive subterranean laboratory.
“The tunnels are huge, and you’re nearly 1,000 feet underground,” adds Roger Rocha, the vice president and chief operations officer for Mission Support and Test Services, the contractor that operates and manages NNSS. “So go to a happy place.”
Collaborating on national and global security
The main entrance to NNSS is about an hour northwest of Las Vegas. From that southernmost portion of the site, NNSS sprawls more than 1,355 square miles (larger than the state of Rhode Island) across both the Mojave and Great Basin deserts. Antelope sightings are common, and “tortoise crossing” signs appear every few miles along the site’s major roads (in fact, many employees have taken desert tortoise training to ensure the safety of this threatened species).
Called the Nevada Test Site until 2010, NNSS is perhaps best known as the location for the majority of America’s nuclear tests. Between 1951 and 1992, 100 atmospheric and 828 underground nuclear tests took place there. Although the United States halted full-scale nuclear testing in 1992, the site is still focused on national and global security work.
“It’s a big place, and we do big jobs—big things that can’t be done anywhere else,” Rocha says.
Rocha and his staff collaborate with people from throughout the nuclear enterprise and various federal agencies on projects ranging from stewardship of the nation’s nuclear deterrent, to nuclear and radiological emergency response training, to nuclear nonproliferation and arms control initiatives, and more.
“We refer to ourselves as the integrator,” Rocha says. “We have the technical expertise to ensure the mission goals are achieved. We’re also responsible for conducting training so that all the work is done safely and securely. It’s a great partnership.”
Rocha also points out that the remoteness of the site allows the Department of Defense and other agencies to carry out tests that require maximum security and unique conditions. “People can come here and do things they can’t do anywhere else,” he says.
For example, at NNSS, first responders can train under conditions they might encounter in real life. “We just did a training literally simulating an acid spill,” Rocha says. “We had 65 firefighters from across the United States that were here, and we opened up the valves and dumped acid. It’s fuming; there are clouds; they’re in full personal protective equipment practicing the skills necessary to neutralize and contain an event like this. This is the only place in the country where you can do that.”
Radiological and nuclear response personnel also visit NNSS to gain firsthand experience working in contaminated facilities. “Close to half a million people have been through here for training,” Rocha says.
Seeking answers underground
Because of its remote location and enormous footprint, NNSS can safely host nuclear weapons–related experiments that can’t be done anywhere else.
Los Alamos, Lawrence Livermore, and Sandia national laboratories each conduct, and often collaborate on, a great deal of national security work in Nevada. All three laboratories have employees based permanently at NNSS, and numerous other employees travel back and forth between the site and their home labs.
In fact, Los Alamos conducts so much work in Nevada that in 2020, the Laboratory created its Nevada Programs Office to streamline and coordinate the Los Alamos work happening at NNSS. “It was one of those things where success breeds demand,” says Don Haynes, who leads the office. “And we’ve had a lot of success out there.”
Following the 1992 moratorium on full-scale nuclear testing, Los Alamos, Livermore, and Sandia pivoted to subcritical experiments as one way to obtain data that’s useful in evaluating the health and extending the lifetimes of America’s nuclear weapons. Subcritical experiments incorporate nuclear materials, such as plutonium, but are configured so no self-sustaining nuclear fission reaction occurs. All subcritical experiments take place inside steel vessels at U1a, the underground laboratory where Vince Gomes is the facilities manager. After these experiments, the vessels are “entombed”—placed at the end of a tunnel and permanently sealed off from the rest of the facility.
Steve Sintay, a Los Alamos project manager and subcritical experiments test director in training, and Chris Frankle, a Los Alamos physicist and subcritical experiments diagnostics coordinator, both point out the crucial nature of these experiments. “In this facility, you get the closest to actual performance of the stockpile,” Sintay says.
Currently, one subcritical diagnostic test bed is operational at U1a: a pulsed x-ray system called Cygnus that’s used for small, focused experiments. Construction has also begun on two more test beds, Zeus and Scorpius, which will allow researchers to conduct subcritical experiments of different sizes and scales with comprehensive diagnostic coverage.
Scorpius, in particular, will play a critical role in understanding and predicting the behavior of plutonium, according to Haynes. Scheduled to be operational by 2030, the 125-meter-long linear induction accelerator represents a partnership among Los Alamos, Lawrence Livermore, and Sandia laboratories, which are each responsible for different parts of the machine. Scorpius will cost more than $1 billion to build and will weigh about one million pounds. Construction on the underground tunnel that will house Scorpius is nearly complete, and the accelerator will be built in pieces and assembled underground.
Like its cousin, the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos, Scorpius will be used to take radiographs of the late stages of weapon implosion. Unlike experiments at DARHT, experiments at Scorpius will use plutonium, which will allow scientists to better identify the effects of plutonium aging and ensure the proper functioning of the nuclear stockpile. Data from Scorpius’ subcritical experiments will inform safety and other updates to nuclear weapons.
“With Scorpius, we’re going to be able to take multiple, high-quality radiographic images of imploding systems—a capability that we do not currently have for subcritical experiments,” Haynes says. “These experiments are being done to answer an important set of questions we’ve been wrestling with.”
Data from these experiments will help calibrate and validate computer simulation codes used to make decisions. Haynes explains that “as our simulations are asked harder and harder questions, we need better research tools, better experimental tools, to make sure that those simulations are staying on track, and they’re giving us accurate predictions.”
Haynes stresses the magnitude of this project. “Scorpius will allow us to have reduced uncertainty and increased confidence in decisions that we make for our deterrent. In the absence of nuclear testing, we need a deeper scientific understanding of the processes that are important for the performance and safety of nuclear weapons.”
Exploring through explosions
Back above ground, researchers at Nevada’s Big Explosives Experimental Facility (BEEF) Kappa West Firing Site use massive amounts of high explosives to conduct training, support global security work, try out different diagnostics, and qualify the vessels that will contain subcritical tests.
Although high explosive (nonnuclear) tests are conducted at other places throughout the nuclear enterprise, the tests at BEEF are substantially more powerful. The key part of this facility’s name is “Big,” says Art Villalobos, the Los Alamos National Laboratory group leader for integrated weapons experiments in Nevada. Villalobos points out that 4,000 pounds of high explosives have been detonated at BEEF and that locations have been identified where up to 50,000 pounds can be detonated.
“Basically, we’re creating explosions in a safe and controlled environment to expose weapons to extreme environments and monitor the weapons to see how they react to the different temperatures,” he continues. “When we test a weapon, we want to determine the rate, distance, and size of the fragments coming out of the weapon, and how they disperse and affect the environment.” The results of these experiments also provide safety information for different weapons systems.
Using high-speed video cameras and radiography, the scientists capture images of the explosions. Each experiment requires miles of diagnostic cables running from the ring site to a control bunker for detailed monitoring and data collection. Other experiments require ground motion monitoring and pressure sensors to help scientists learn to detect and distinguish different types of detonations.
“We set off large amounts of explosives to see what sort of diagnostic signals you would record either seismically or with infrasound,” Haynes says. “This is an important part of nuclear nonproliferation—making sure that we have the ability to detect anyone who is attempting to evade detection for a nascent nuclear weapons program.”
Perfecting the detecting
Approximately 11 miles north of BEEF is another experimental area called P Tunnel. Unlike U1a, which is accessed by elevator, P Tunnel is bored into the side of a mesa; scientists can walk in from the parking lot and take a train to various locations in the tunnel.
Today, an ongoing test series inside P Tunnel is helping scientists develop new ways to identify whether an adversary is hiding low-yield nuclear testing or developing nuclear weapons in violation of treaties. These tests improve U.S. arms control and nuclear nonproliferation verification and monitoring capabilities.
Researchers use the data collected, along with legacy data from actual nuclear tests, to validate physics-based computer models. The findings will extend their explosion detection capabilities to lower yields and different geological settings and will advance their ability to differentiate low-yield nuclear explosions from other seismic activity, such as mining operations and small earthquakes.
“We’re using high explosives and extremely tiny releases of gases and particulates that we can trace to generate and collect data needed to validate our physics-based models,” says Gordon MacLeod, a geophysicist at Los Alamos National Laboratory who is involved in the P Tunnel experiments. “On the surface we’re testing whether we can track the tracer release to see if the models and sensors are working properly.”
Scientists are also researching ways to detect low frequency electromagnetic signals, similar to those that would be created by a nuclear detonation. “We built an electromagnetic source that looks like a giant coil inside the tunnel, and we were able to detect low frequency signals that were actually traveling from that source through more than one kilometer of rock up to the surface,” MacLeod says.
Other experiments will be conducted underground in the southern part of NNSS in an area called Rock Valley, which is known for shallow seismic activity. “A lot of our adversaries test in active earthquake areas,” says Cathy Snelson, a project manager in the Los Alamos Geophysics group. “If you want to set off underground nuclear explosions, you can hide them in a seismically active area because earthquakes are energy-wise a lot bigger than an explosion is, and explosions tend to get buried in the noise.”
Snelson says this testing location provides a unique opportunity to compare experiment results to shallow earthquake seismic activity data recorded in the same region decades ago. “From a nonproliferation and monitoring point of view, this has never been done before. We’ll be placing a ton of sensors out both on the surface and below the ground. These will be unprecedented datasets. The amount of data, both geological and geophysical, that we’ll be collecting is just incredible.”
The researchers point out that the results of these experiments will contribute to treaty monitoring and negotiations. “Scientists from all three national labs and the Nevada National Security Site are working together on this. We’re extremely excited,” Snelson concludes.
Continuing the commitment
Although the scope of the work taking place at NNSS is as vast as the Nevada desert, every training, experiment, and test shares a common purpose: to safeguard and advance national and global security. The commitment of the workforce to fulfill this mission is evident throughout the site, according to Haynes. “Much of the workforce travels more than an hour to work every day and puts in 10-hour days in challenging environments,” he notes.
Brian Brown, the facility manager at P Tunnel, agrees and says he tells his team members what an important role they play in national security. “You’re responsible for protecting United States citizens and global citizens. Know that when you’re digging a trench, or you’re putting up extra lighting, or you’re making sure the ventilation is flowing, your work is having a more significant impact than you can imagine. You need to understand potentially how big of an impact you’re having on the safety of America and the world in general.”
That collaborative spirit is also evident among those involved in the Scorpius project underway at U1a. According to Dave Funk, the vice president of Enhanced Capabilities for Subcritical Experiments at NNSS and former senior director of the Advanced Sources and Detectors Project Office at Los Alamos National Laboratory, nearly 800 people from Los Alamos, Livermore, and Sandia national laboratories, NNSS, and the National Nuclear Security Administration have contributed to Scorpius so far. “What is really amazing about this project is the complexity of the partnerships and the process of bringing all these different cultures together and leveraging their strengths,” he says.
The collaboration is indeed amazing but perhaps not surprising. After all, teamwork across the enterprise has been key to the success of the Nevada National Security Site since its very first full-scale nuclear test in 1951. For more than 70 years, the dedication of the scientists, engineers, and craftspeople who work at the site remains unchanged, according to Haynes.
“It’s an amazing set of people,” he says. “What they’re doing is a great service to the country.” ★