Where a crown jewel once stood in NASA’s ambitious plans for human space exploration now lies a decontaminated nuclear grave. Current regulations bar NASA from building or researching fueled nuclear devices. Yet in a bygone era five decades ago, the space agency’s future was dependent on one: the Plum Brook Reactor Facility in Sandusky, Ohio. NASA turned on its first, last and only nuclear fission test reactor in 1961 to research nuclear-powered airplanes, then eventually nuclear-powered space rockets. But the mounting cost of the Vietnam War and waning interest in manned space exploration led President Richard Nixon to mothball the facility in 1973. “This is the only reactor facility that NASA had or has since,” said Peter Kolb, an engineer at NASA Glenn Research Center who manages the reactor’s decommissioning program. “When they shut it down, the workers didn’t realize that it was going to be shut down for good. They thought, ‘Oh, we’ll be back in a month.’ But that never happened.” After 25 years of dormancy and an additional 14 years of decommissioning work, however, workers demolished the last-standing structure of the 27-acre research facility (below) on May 31, 2012. “We are expecting to have the license termination from the Nuclear Regulatory Commission sometime this summer,” NASA Glenn spokesperson Sally Harrington wrote in an email to Wired. Before the facility’s walls came tumbling down, however, NASA granted Wired an exclusive look inside. Take a tour of NASA’s historic romp in nuclear research in this gallery. Images: 1) Kolb stands where an 80-ton lead door once cordoned off a rear entrance to a “hot” laboratory. A crane would lift irradiated experiments into thick-walled rooms where workers could study them. (Copyright Dave Mosher) 2) NASA’s mothballed Plum Brook Nuclear Reactor facility in 1981. (NASA)

Nuclear Rocket Research NASA’s reactor was designed to develop a nuclear bomber, but supporting the development of a nuclear-powered rocket booster became the facility’s prime mission beginning in 1961 through its close in 1973. Called NERVA, short for “nuclear engine for rocket vehicle application,” engineers by 1968 had built enough components to create a space-ready prototype rocket. They expected a finished design might tug the same payload as a chemical rocket could, yet two to three times more efficiently — a huge help for both reducing launch costs and the duration of manned missions. Although NERVA and other nuclear rocket components were tested elsewhere, Plum Brook engineers used their reactor to test materials and components that would have made their way into a real nuclear rocket. (A nuclear reactor’s constant neutron bombardment can eat away at metal and other materials.) Images: NASA

The Reactor Building Half buried in the ground, half poking out, a 100-foot-tall steel containment vessel (above) was designed to keep any nuclear mishap from reaching the outside world. NASA indefinitely mothballed the reactor building (below) and its support structures in 1973, after then-Congressman Charles Mosher (no relation to the author) failed to carve a new niche for the facility. From January through June of 1973, workers removed the reactor’s fuel, disposed of obvious radioactive waste and sealed a maze of pipes. A skeleton crew then monitored the site until 1998, when NASA decided to decommission the facility for an anticipated $160 million. The cost to remove contaminated building materials, verify decontamination and demolish the campus ultimately reached $253 million — more than double the cost to build the facility when accounting for inflation. Images: 1) Construction of the reactor’s containment vessel, or dome, in 1957. (NASA) 2) The decommissioned reactor building in November 2011. (Copyright Dave Mosher)

Energetic Core Although NASA’s lone reactor was capable of pumping out 60 megawatts, it wasn’t designed to produce electricity. Instead, the core’s uranium-235 fuel spit out countless neutrons to bombard 32 holes, each packed with a small experiment. The experiments were often materials and components designed to exist around the core of a nuclear rocket to see how they’d fare, but researchers once popped in a moon rock brought back by Apollo astronauts. “They were exploring the idea of a trash can-sized reactor for a moon base,” Kolb said. “They wanted to know what would happen to the lunar [soil] if exposed to a high neutron flux.” Images: 1) The blue light of Cherenkov radiation, which energetic particles shed if they move faster through water than light can. (NASA) 2) Workers load experiments into the core. (NASA) 3) A schematic of the reactor capsule and core, located in the center of the containment dome. (NASA)

Booms and Busts On May 21, 1961, technicians took NASA’s reactor “critical,” which is a major milestone in reactor construction and a proving ground for safe operation. (Criticality is when the number of neutrons spit out by radioactive fuel begins to outnumber the neutrons lost to absorption.) Just one week after reaching criticality, however, then-president John F. Kennedy scuppered the $1 billion nuclear airplane program — the centerpiece of the reactor’s mission. “The idea was you’d have a long-range bomber that you’d never have to refuel. Theoretically, it could have had an indefinite flight time,” said Peter Kolb. “But the reactor had so much weight that the program never got off the ground.” Yet all was not lost. Two months after killing the nuclear bomber, President Kennedy tasked the facility with developing a nuclear-powered rocket called NERVA. (The reactor eventually closed for good in 1973.) Images: 1) The reactor’s control room as engineers prepare to take it critical. (NASA) 2) Workers gather around the reactor’s control room as nuclear engineer Bill Fecych permanently powers the facility down on Jan. 5, 1973. (NASA)

Radioactive Contamination Decommissioning and demolition of the reactor facility began in 1998, after roughly 25 years of delay, and took until 2012 to complete. The radiation levels during Wired’s visit were at essentially background levels, thanks to years of waste removal, but workers nonetheless checked for contamination during entry and exit from the hollowed-out nuclear tomb. Images: Copyright of Dave Mosher

Reduction in Force NASA’s breakup with nuclear propulsion came as a handwritten memo to the reactor’s director. Layoffs promptly began January 5, 1973, and operators shut down the facility for good six months later. Some workers fully expected funding to be restored and to return to work. “They left coffee cups, ashtrays, newspapers, family photos, pin-up calendars — you name it,” Kolb said. In the heat of the layoffs, some employees chalked their fury onto a blackboard that remained untouched until decommissioners arrived 25 years later. Images: 1) A blackboard graffitied by laid-off workers. “RIF” stands for “reduction in force.” (NASA) 2) An employee’s calendar left alone for more than two decades. (NASA)

Survey for Destruction Before a reactor site can be demolished, filled in or tossed into a dump, almost every square inch must be scanned for radioactive contamination and “released” when no significant amount is present (red X’s, above). To speed up the job, decommission workers shaved off about a quarter of an inch of the facility’s concrete floors and tagged the rubble as radioactive waste (below). “It was more economical for us to do that than to scan every square inch of the floor,” Kolb said. Other workers cut back piping and conduits to create flat, easy-to-scan surfaces (bottom) and sand-blasted contaminated paint. Images: Copyright of Dave Mosher

Old Airlock Just outside of the 100-foot-tall steel containment vessel were control rooms and office spaces. A two-door airlock (above, bottom-right) separated the containment vessel from this common area. A small negative pressure sucked air into the containment vessel, keeping any stray contamination out. William Stoner, a radiation safety officer for the reactor decommissioning project, stands in front of the same spot in November 2011. Images: 1) NASA 2) Copyright of Dave Mosher

Shrapnel Shields The center of the containment vessel housed a pill-shaped pressure tank that contained the loveseat-sized core. When the core needed servicing, workers used a giant crane to remove three shrapnel shields (above). Each 20-ton steel lid was placed on top of the pressure tank during normal operation to prevent a catastrophic, explosive nuclear mishap from piercing the containment vessel. (The facility experienced no such mishaps.) Images: 1) Workers access the reactor core after lifting away the shrapnel shields. (NASA) 2) A view of the hollowed-out containment vessel in November 2011. (Copyright of Dave Mosher)

Deep Quads To shield workers from the fueled core’s radiation, three 25-foot-deep quadrants, or “quads,” (above) were filled with water. A series of water-filled canals (below), which included a railroad-like transportation system, helped workers safely and easily move spent fuel and experiments throughout the facility. In total, the facility housed 780,000 gallons of water in its quads and canals, or about 15 percent more water than an Olympic-sized swimming pool. A fourth and water-free quad (below in November 2011) harbored experiments that couldn’t stay wet for days, weeks or months. One of the experiments was a cryocooler to recreate the cold of outer space for an experiment while the reactor supplied the radiation. Images: 1) NASA 2) Copyright of Dave Mosher 3) Copyright of Dave Mosher

Pressure Vessel Cold War-era nuclear reactor facilities simply weren’t built to be taken apart. Early in the reactor’s construction, workers lowered its uniquely designed 31-foot-tall, 9-foot-wide pressure vessel into the center of the far larger containment vessel (above). Decommission workers painstakingly removed the device over the years and sent its irradiated pieces to a nuclear-waste storage site. Before the pressure vessel area could be approved for demolition, workers also had to remove asbestos insulation wedged between the steel and the concrete. Images: 1) NASA 2) A Nov. 2011 view looking up the the scraped-down tube where the pressure was once housed. (Copyright of Dave Mosher)

Radioactive Laboratory A crucial addition to the reactor in 1963 was a hot cell laboratory containing seven thick-walled rooms (above) to analyze experiments pulled from the reactor core. Researchers could poke, prod, cut, photograph and otherwise toy with “hot” radioactive materials with a view from a mineral oil-filled window. Images: 1) NASA 2) The hot cell laboratory, or gallery, in November 2011. (Copyright of Dave Mosher)

Inside a Hot Cell Workers who used a hot cell trained to use its mechanical manipulators by threading a needle with string. Each room had a unique purpose, from slicing up samples or determining their hardness to studying objects under a microscope or probing their chemistry. Images: 1) The view from inside of one of seven Plum Brook Reactor Facility hot cells. (NASA) 2) A decommissioned hot cell in November 2011. (Copyright of Dave Mosher)

Concrete Plugs and Cutie Pies Behind the hot cells, a crane (not pictured) raised samples from a submerged canal and into the heavily shielded rooms. Technicians routinely inspected the rooms with “cutie pie” radiation detectors — nicknamed for their small size — after removing massive 60-inch-thick concrete plugs (above). During the decommissioning process, workers had to dig up and remove metal plumbing in this room (below) that was laced with radioactive contamination. Images: 1) NASA 2) Copyright of Dave Mosher