While the nation sleeps

It’s a typical weekday, and the Department of Energy’s Oak Ridge National Laboratory buzzes with activity. Its 7,400 employees move across the 4,400-acre campus. Thousands of visiting scientists cycle through its user facilities. Roads hum with traffic.

As night falls, the energy doesn’t disappear — but it changes.

Buildings go dark and parking lots empty. Voices fade, traffic thins. Across the campus and the surrounding 37,000-acre reservation, the lab grows quieter, stiller.

But the science doesn’t stop.

While much of the country is relaxing after dinner with TV or a book, or turning out the lights and turning in, ORNL's supercomputers calculate, instruments pulse, the reactor is online and monitored, and critical infrastructure operates under constant watch. Overnight, a smaller workforce takes over, and operators, technicians, engineers, first responders and security officers keep one of the nation’s largest scientific institutions running safely, steadily, without pause.

Their work sustains discovery, protects critical systems and ensures the research that supports America’s energy future, competitiveness and security never misses a beat.

2200 hours | Laboratory Shift Superintendent’s Office (LSS)

It’s the middle of the night, and facilities across ORNL are running with their usual consistency. If a storm hits, an emergency happens or an accident occurs, who do you call?

ORNL relies on the LSS Office, which functions like an on-site 911 service, dispatching emergency responders wherever they are needed across campus. Fires, injuries, accidents, spills, potential security breaches or suspicious activity — calls to the LSS are answered 24 hours a day. The LSS team is available at all hours to assist employees, from routine needs to unexpected situations, including during work-related travel.

“We’re here to keep an eye on the place. We make sure that if something happens, we can provide a quick response,” said LSS team member Kevin Ross. LSS staff members respond to fire runs, ambulance runs and rescues, securing the scene until an incident commander arrives.

The LSS manages ORNL’s emergency plan and activates the Laboratory Emergency Response Center (LERC) if an operational emergency occurs. In a crisis, at any hour, LERC mobilizes the emergency response, issues protective actions to ORNL staff and dispatches first responders, including the fire department and Protective Force.

At all times, the LSS monitors the laboratory’s alarm systems and area weather, ensuring the lab is prepared for adverse incidents. If the power goes out at 2 a.m. because a tree falls on powerlines, the LSS team knows. After assessing the situation, LSS dispatches experts, such as electricians and the safety and roads and grounds teams, to fix the issue as quickly as possible. Power outages are not mere inconveniences at ORNL; they can affect freezers, which could impact experiments; stop production of crucial materials; cause security risks; stop elevators; and create many more serious situations. Handling these incidents cannot wait until morning.

That vigilance not only supports overnight activities but also ensures that when more than 7,000 staff arrive in the morning, they can continue their work without interruption.

2300 | Fire Department and EMS

In ORNL’s research facilities, a busy night across the campus is a sign of success. Experiments run uninterrupted, and science moves forward. For the lab’s Fire Department and Emergency Medical Services teams, however, a quiet night is a good night.

On those nights, alarm panels don’t flash. Radios don’t sound emergency dispatches. Fire engines and ambulances sit silent in their bays. That calm gives crews time to complete monthly testing of fire extinguishers, inspect buildings and perform routine maintenance. Quiet shifts allow them to complete required training and drill alongside Pro Force, the lab’s law enforcement team, for scenarios ranging from evacuations to bomb threats. Ambulances are inventoried and sterilized, stocked with specialized equipment.

That preparation matters because when calls do come in, they are often critical.

“Most of the things that you can do in the ER, we can do in the back of this truck,” said Chayse Lyon, who is a fire captain and a paramedic. Imaging, such as CT or MRI scans, is the primary exception. Lyon and his peers can pack wounds, reverse allergic reactions, treat hypothermia with warmed IVs, clear airways via suction, perform a tracheotomy and restart a heart. If time is too short to find a vein, they can drill directly into the bone marrow to administer fluids in seconds.

Because ORNL has nuclear facilities, the team maintains a full complement of hazmat and radiation decontamination supplies, supported by an in-depth protocol book that serves as a reference for nearly any situation.

“If there’s any second-guessing on what’s going to happen, it’s all in here,” Lyon said.

That readiness is reinforced by experience drawn from city, county and regional departments.

“This is where the best of the best ends up,” said fire protection inspector Michael Ridge. “You bring large amounts of experience when you come out there, and it’s from different departments everywhere.”

Midnight | Protective Force (Pro Force)

Pro Force, ORNL’s highly trained police force, is always ready.

Pro Force protects the lab 24 hours a day, every day of the year. Early in the morning, in the still-dark hours before the first workers begin arriving for the morning shifts, the Pro Force Team is at the gate. Late at night, long after most of the lab staff have left, Pro Force is still on the job.

“We have assets that need protection around the clock,” said Pro Force Lieutenant Ty Wolfe. “We are the eyes and the ears of the lab. Our officers always, but especially at night, have to be extra vigilant.”

Police vehicle blocking a street at night with flashing lights; officers inside patrol cars monitoring the situation.

Wolfe said they’re also extra-prepared. Many Pro Force employees have multiple years of military or special forces experience. Many also have experience on bomb squads, SWAT teams, special investigative or narcotics groups, and other elite law enforcement teams.

“The most important things are the assets we protect,” he said. “We protect the people, the buildings and the research that goes on here. We are the first and last line for many of those systems to be protected, especially the people, and we take a strong and proactive approach to make sure they are safe.”

0100 | Steam Plant

Beneath the quiet campus, an extensive network of steam and water systems flows.

Roughly 17 miles of steamline run under valleys and buildings, delivering heat and water to facilities across ORNL. Overnight, those systems are monitored from a control room in Bethel Valley, where mechanical utilities operators rotate through shifts to ensure constant oversight.

Operator Nathan Chancey sits surrounded by 28 monitors, scanning for irregularities and listening for alarms. Any unexpected change, such as pressure fluctuations, temperature shifts, leaks, demands immediate attention.

*Composite image of the ORNL facility and full moon.

“When you first start, it can feel like you’re just watching screens,” Chancey said. “But you realize quickly that everything depends on those systems working.”

Operators must maintain water and steam systems at all hours. That includes sampling and testing boiler water chemistry, monitoring water levels in more than 100 pits across campus, and ensuring chillers keep temperatures within required ranges for supercomputers and sensitive instruments.

Man in a control room surrounded by multiple monitors displaying industrial system diagrams and data.

Four operations teams run the Steam Plant, each trained to handle a wide range of systems. Overnight staffing is leaner than during the day, but the responsibilities are the same. Operators respond to leaks, equipment failures, traffic accidents that damage infrastructure – even, occasionally, issues originating off-site that affect the lab’s operations.

As the campus sleeps, their vigilance keeps ORNL running.

0200 hours | Radiochemical Engineering Development Center (REDC)

In the middle of the night, most of Melton Valley is still and quiet.

But the concrete-block REDC is alive with activity.

Inside, specialized technicians, already well into a 12-hour shift, use remote-controlled mechanical arms to work with crucial isotopes inside hot cells, heavily shielded enclosures that allow them to safely handle radioactive materials. Looking through thick, lead-glass windows, they perform complicated chemistry that will lead to isotopes for medical treatments, nuclear power, national security and other needs.

Worker inspecting equipment on a manufacturing or lab assembly line, using a workstation with tools and machinery nearby.

“There’s always someone here,” said Dan Bettinger, leader for C Shift, one of four teams rotating through overnight operations. “We always have someone covering the control room.”

At REDC, time matters in a very real way. Many of the isotopes produced here decay quickly, and delays would ripple outward, affecting medical treatments, research schedules, and national security.

REDC staff work with some isotopes that have short half-lives – meaning it is crucial to ship them in a timely manner. For example, actinium-225, is in high demand for targeted alpha therapy cancer treatments. Its half-life of only 10 days is beneficial when Ac-225 is used to target tumors, because it decays quickly with minimal effect on surrounding healthy cells. But its rapid decay creates a challenge for the skilled professionals charged with separating and purifying the isotope and rushing it to customers on time. That means Hot Cell Operations Group staffs the REDC 24 hours so that “day shift” teams meeting Ac-225 shipping and delivery deadlines can start work earlier – sometimes as early as 4 a.m.

Another short-lived isotope produced at REDC, californium-252, used for starting up nuclear reactors and other industry applications, has a half-life of just more than 2½ years. ORNL is the only source in the western hemisphere for the in-demand energy isotope, which is produced about every two years.

At REDC, the night’s pace is driven by materials that decay and deadlines that cannot slip.

A short drive west, the night grows quieter, and the work takes on a different rhythm.

ORNL carbon fiber operations personal is working on a machine

0300 hours | Carbon Fiber Technology Facility (CFTF)

The 42,000-square-foot CFTF is a hub of activity during the day. But it sits mostly dark and still at night, unless a carbon fiber run is under way.

When it is, the facility operates continuously, because the science demands it.

Carbon fiber production cannot be paused and restarted without compromising the results. Temperatures, tensions and chemical reactions must be tightly controlled, hour after hour, day after day, without interruption, during a run.

“These 24-hour runs typically last about two weeks,” said carbon fiber line technician Gary Vance. “The first 24 hours is as important to the research and development as it is to the manufacturing itself.”

That first day produces enough material for testing, guiding adjustments throughout the run. Each night contributes incremental data, small refinements that bring carbon fiber closer to being affordable and scalable for broader use in applications such as automotive, energy, aerospace and construction.

Overnight, the goal isn’t speed, it’s consistency.

“We want to make it as low-cost as we possibly can while still delivering a good-quality product,” Vance said.

As adjustments progress steadily through the dark hours, another group elsewhere on campus is watching systems most people never see but everyone depends on.

0400 hours | High Flux Isotope Reactor (HFIR)

The ORNL scientists who call campus home aren’t the only ones who benefit from the lab’s unique user facilities, such as the HFIR research reactor. Visiting partners and scientists from all around the world conduct experiments at HFIR – sometimes even overnight.

HFIR steadily releases powerful unbroken beams of neutrons for neutron scattering research. A nuclear reactor can’t be turned on and off like a light, so once a HFIR fuel cycle starts, it doesn’t stop for about 25 days. Researchers from around the globe, around 500 of them a year, jockey for every slot of time on its suite of instruments. Limited beam time and irradiation space mean experiments and isotope production take place whenever reactor time is available, whether it’s noon on a Wednesday or 2 a.m. on a Friday.

“Some researchers can log in remotely and monitor their experiments, but most of them are here, whether it’s during the night or during the day,” said HFIR shift supervisor Michael Flory.

Continuous reactor operation means constant staffing day and night. Overnight operations are supported by a smaller team responsible for running the reactor, monitoring radiological conditions, and maintaining system readiness.

Whether HFIR is operating or between cycles, people are always present in the building.

It’s up to senior radiological control technician Joe Galloway to make sure the environment is safe for staff and visitors alike, no one risking radiation exposure.

“At night, I’m the sole responder,” Galloway said. “If anything happens, it’s mine to deal with – I either call help in, or I contain the situation until day shift comes in. I always have three operators, and if HFIR is running, I have users and researchers downstairs. It’s my job to take care of them.”

Overnight work when HFIR isn’t active includes supporting experiments, producing isotopes and performing routine inspections and system checks that prepare the reactor for future operations. That continuous presence allows HFIR to remain available to the global scientific community and sustain research and applications that extend well beyond the laboratory.

0500 hours | Spallation Neutron Source (SNS)

Across a valley and up a ridge from HFIR, another powerful neutron source operates around the clock on a different scale and a different process.

The SNS is an accelerator-based research facility that produces microsecond pulses of neutrons through a process called spallation. Either shutting down or restarting SNS is a highly complex and expensive process; besides, studies using the instruments often require long uninterrupted periods of beam time to produce reliable, high-quality results. So SNS runs continuously with as little downtime as possible. Every minute of limited beam time is coveted by hundreds of users worldwide.

Target control room at the Spallation Neutron Source

A dedicated five-person operations team monitors the accelerator around the clock, responding immediately to alarms and system changes to keep the beam running safely and efficiently.

The team works together to operate the accelerator and check for leaks in the Klystron Gallery, which supplies power to more than 80 superconducting structures directly beneath each station. It’s a process that requires constant monitoring.

This constant operation ensures that visiting scientists can maximize their research time and that the facility delivers the data needed to support scientific discoveries that may take years to fully emerge.

0600 hours | Supercomputer utility squad

With more than 1,700 researchers worldwide relying on the Oak Ridge Leadership Computing Facility’s (OLCF) Frontier to tackle some of science’s biggest challenges, the exascale-class supercomputer sees little downtime. At nearly any hour, Frontier is running complex codes, from molecular dynamics to stellar astrophysics, driving discoveries across disciplines. Keeping a system of this scale running nonstop means someone must be on site every minute of every day and night.

Overnight operations ensure that Frontier and other OLCF systems remain continuously available to the global research community. Because workloads run around the clock, night shift control room operators play a critical role in identifying and resolving issues as they arise, rather than waiting until normal business hours. This constant oversight minimizes downtime and helps protect the momentum of time-sensitive research.

The overnight team serves as the first line of response when problems occur. By monitoring system dashboards, conducting physical rounds, and keeping watch over supporting infrastructure like power and cooling, operators can quickly identify abnormal conditions and escalate them to the appropriate experts. Their ability to stabilize systems during outages or unexpected conditions helps prevent small issues from becoming major disruptions.

Paul Abston standing in front of the OLCF

“Operators work 24 hours a day, seven days a week, 365 days a year,” said Paul Abston, HPC Infrastructure Operations Group leader. “They’re my extra 12 arms and my extra 12 eyes.”

0700: Autonomous labs

But in some places, the science never stops, even when nobody’s there. Self-driving systems across the lab — combining artificial intelligence, robotics, automation, advanced instruments and leadership-class computing — have kept experiments moving long after a building grows quiet.

These systems run continuous cycles: design, build, test and learn.

Robotic systems prepare samples, create and test materials, collect images, tune experimental conditions and search for patterns too complex for humans to track in real time.

Then the systems choose what to try next.

ORNL Researcher looks into a shiny piece of equipment

“They can recognize something interesting and pull the thread to dive deeper, using new information to guide the next set of experiments."

— Rob Moore, Director for the Interconnected Science Ecosystem (INTERSECT) Initiative at ORNL

ORNL initiatives like INTERSECT and Labs of the Future are connecting instruments, computing resources, data systems, and scientific expertise in a collaborative human-AI research ecosystem. These cooperative systems are accelerating research in energy materials, microelectronics, quantum science, chemistry and beyond.

Researchers designed these systems and continuously contribute their intuition, creativity and perspective. But autonomous systems extend their reach, carrying experiments forward, sorting through data and preparing results for scientists to interpret when they return.

Morning comes. The work continues.

As the sun rises, isotopes produced overnight are prepared for shipment. ORNL supercomputers continue running programs and solving new problems across vast networks. Facilities are online, functioning smoothly. Researchers return not just to completed experiments, but to new analyses, new questions and new paths forward. Emergency responders hand off the night’s report to the next shift.

The campus begins to fill again with scientists, engineers, craft workers and support staff, mostly unaware of the quiet vigilance that carried ORNL through the night.

When the world slept, the lab was awake. Robotic assistants keep moving. Instruments keep measuring. Data keeps flowing. AI keeps learning.

And tonight, it will do it all again. Because at Oak Ridge National Laboratory, science never sleeps.