Underground Cathedrals of Radiation and Zones of Irreversible Strain

[Image: Nevada test site, Google Maps, filtered through Instagram.]

There’s a great line in Tom Zoellner’s book Uranium: War, Energy, and the Rock That Shaped the World where he describes the after-effects of underground nuclear tests. Zoellner writes that, during these tests, “a nuclear bomb buried in a deep shaft underneath a mountain would vaporize the surrounding rock and make a huge cathedral-like space inside the earth, ablaze with radioactivity.”

I thought of Zoellner’s vision of a “huge cathedral-like space inside the earth” recently while reading a paper by Colin N. Waters et al., called “Recognising anthropogenic modification of the subsurface in the geological record.” Among other things, the authors describe the long-term “structural effects of subsurface weapon detonations.”

[Image: Nevada test site, Google Maps, filtered through Instagram.]

They suggest that these detonations produce spaces—such as collapse cones and debris fields—that have “no direct natural analogue,” although they do helpfully contrast weapon-test craters with meteor-impact sites. (The authors also break underground nuclear test sites down into “zones,” which include a “zone of irreversible strain,” which is an amazing phrase.)

The larger purpose of their paper, though, is to look at long-term “signatures” that humans might leave behind in our underground activity, from nuclear tests to mineralogical carbon-capture to deep boreholes to coal mines. Will these signatures still be legible or detectible for humans of the far future? On the whole, their conclusion is not optimistic, suggesting instead that even vast subterranean mines and sites of underground nuclear weapons tests will fade from the terrestrial archive.

“Many of the physical and chemical products of human subsurface intrusion either do not extend far from the source of intrusion, lack long-term persistence as a signal or are not sufficiently distinctive from the products of natural processes to make them uniquely recognisable as of anthropogenic origin,” they write. “But the scope and complexity of the signals have increased greatly over recent decades, both in areal extent and with increasing depths, and seem set to be a fundamental component of our technological expansion. There will be some clues to the geologist of the far-future, when historical knowledge records may not be preserved, that will help resolve the origin.”

[Image: Nevada test site craters, courtesy of the National Nuclear Security Administration Nevada Site Office Photo Library.]

Nevertheless, it is totally fascinating to imagine what future archaeologists might make of Zoellner’s “huge cathedral-like space[s] inside the earth, ablaze with radioactivity,” long after they’ve collapsed, and where sand has been fused into unnatural glass and anomalous traces of radiation can still be found with no reasonable explanation for how they got there.

Could future archaeologists deduce the existence of nuclear weapons from such a landscape? And, if so, would such a suggestion—ancient weapons modeled on the physics of stars—sound rational or vaguely insane?

(Vaguely related: “fossil reactors” underground in Gabon.)

Terrestrial Concussion / Infinite Half-Life

[Image: Courtesy Xenon Collaboration, via ScienceNews].

Earthquakes, popularly seen as discrete, large-scale events that occur only once every few years—once a decade, once a century, once every thousand years—turn out to be nearly continuous. There are always earthquakes.

According to ScienceNews, “millions of tiny, undetected earthquakes rumble through the ground” every day in California. These are “quakes of such small magnitude that their signals were previously too small to be separated from noise.”

In other words, while we wait for the Big One—a true seismic event with the power to punctuate and interrupt everyday life—there are millions of smaller earthquakes constantly rattling the floors, walls, and roads we consider stable.

I’m reminded of a recent article in the New York Times about football player Ryan Miller. “Miller has had 10 concussions in all,” we read, “and that is to understate his battering. The brain sits in fluid inside the armor of a skull, and even nonconcussive whacks can result in brain colliding with bone. A couple of hard hits can come to resemble a concussion. The average football player, according to Cantu, takes 600 to 800 hits in high school and 800 to 1,000 in college.”

Concussions are like earthquakes, in other words: we wait for the Big One, but this means that, by definition, we miss the cumulative effects of all the little shocks along the way. Everything is moving; the earth is not stable; the landscape is jolting and cracking at a concussive rate, every day, beneath our feet.

On the opposite side of this temporal spectrum, the same website, ScienceNews, also reported that some radioactive decay takes so long, they can outlast our current universe.

“It takes 1 trillion times the age of the universe for a xenon-124 sample to shrink by half,” we read. “The decay, seen in xenon-124 atoms, happens so sparingly that it would take 18 sextillion years (18 followed by 21 zeros) for a sample of xenon-124 to shrink by half, making the decay extremely difficult to detect.”

That’s a bit of an understatement: it means you would need a machine significantly older than the universe to detect and measure these moments of decay.

[Image: Xenon, via Images of Elements].

The breakdown of this specific example—the element xenon-124—involves something called “two-neutrino double electron capture,” and I won’t even pretend to understand what it means. Nevertheless, what interests me here is the implied possibility that, well, on a universal timescale, everything is decaying. Everything is breaking down. But it occurs on a scale so huge it is inaccessible to human experience, certainly, but perhaps even to human cognition.

Imagine an element that decays only once every 750 trillion years. (Our current universe is 14 billion years old.) Imagine a creature living 749.999 trillion years, arrogantly thinking that its world is immortal.

In any case, this feels like the exact inverse of the previous example: while we’re on the hunt for radioactive decay, or while we’re out there looking for millions of overlooked mini-quakes and micro-concussions, we might actually miss detecting these massive punctuations of time, epic cycles so rare and daunting that our own universe cannot accommodate them.

For those attentive enough, in other words, there are concussions and earthquakes constantly; yet, on a large-enough timescale, everything decays, everything breaks down, everything has a half-life. Everything is radioactive. In the midst of all that, we make breakfast and take the subway to work.

The Landscape Architecture of Crisis

[Image: An only conceptually related photo from a volcano in Java, taken by Reuben Wu].

The invisibility of underground fires makes them particularly surreal and difficult to imagine: flames with no real room to flicker, moving slowly forward through the planet, relentlessly burning their way ever deeper into the landscape from below.

Whether that fire was caused by the ignition of a coal seam—as in Centralia or, my favorite example, in Australia’s Burning Mountain—or because subterranean strata of human-generated trash have caught fire, these events make for an especially spectral presence in the landscape. They remain entirely out of view except for the haze of their atmospheric effects, as they fill the air above with toxic gases.

This already strange phenomenon is hitting a whole new level of apocalyptic artificiality in a landfill outside St. Louis, Missouri. There, an underground fire is at risk of igniting old nuclear waste from U.S. weapons programs.

As the AP reports, “Beneath the surface of a St. Louis-area landfill lurk two things that should never meet: a slow-burning fire and a cache of Cold War-era nuclear waste, separated by no more than 1,200 feet.”

It’s worth pointing out that “the waste was illegally dumped in 1973 and includes material that dates back to the Manhattan Project, which created the first atomic bomb in the 1940s.” In many ways, then, this was an obvious problem just waiting to reassert itself.

An “emergency plan” has now kicked into gear to help fend off the potentially “catastrophic event” that would occur if these two things meet—the dormant deposit of nuclear waste and the respiring event of the underground fire.

In effect, this plan is a massive undertaking of design: it is landscape architecture as a tool against crisis.

New structures called “interceptor wells” are being constructed, for example, to maintain a kind of thermal quarantine line between the fire and the nuclear waste—however, the fire already appears to have circumvented these buffers, at least according to the AP. For example, some safety reports from the site have allegedly “found radiological contamination in trees outside the landfill’s perimeter,” implying that the nuclear waste has already, in at least some capacity, entered the biosphere, and “another showed evidence that the fire has moved past two rows of interceptor wells and closer to the nuclear waste.”

Yet another report ominously claims that the management company in charge of the landfill simply “does not have this site under control.”

This slow-burning apocalypse brings to mind our earlier look at writer Robert Macfarlane’s recent work on the vocabulary we use for certain landscapes, how words come and go over time and how spatial atmospheres can be verbally communicated.

Is there a proper landscape term for a subterranean catastrophe ready to burst through the surface of the world and forever change things for the worse in its immediate vicinity?

(Thanks to Ben Brockert and Kevin Iris for the tip!)

Landscapes of Inevitable Catastrophe

[Image: Illustration by David McConochie, courtesy of The Art Market, via The Guardian].

Last month, The Economist reported on the widespread presence of radioactive tailings piles—waste rock left over from Soviet mining operations—in southern Kyrgyzstan. Many of the country’s huge, unmonitored mountains of hazardous materials are currently leaching into the local water supply.

In a particularly alarming detail, even if you wanted to avoid the danger, you might not necessarily know where to find it: “Fences and warning signs have been looted for scrap metal,” we read.

Frequent landslides and seasonal floods also mean that the tailings are at risk of washing downriver into neighboring countries, including into “Central Asia’s breadbasket, the Fergana Valley, which is home to over 10m people… A European aid official warns of a ‘creeping environmental disaster.'”

Attempts at moving the piles have potentially made things worse, releasing “radioactive dust” that might be behind a spike in local cancers.

In addition to the sheer aesthetic horror of the landscape—a partially radioactive series of river valleys, lacking in warning signs, that writer Robert Macfarlane would perhaps call “eerie,” a place where “suppressed forces pulse and flicker beneath the ground and within the air… waiting to erupt or to condense”—it’s worth noting at least two things:

One, there appears to be no end in sight; as The Economist points out, the neighboring countries “are hardly on speaking terms, so cross-border co-operation is non-existent,” and the costs of moving highly contaminated mine waste are well out of reach for the respective governments.

This means we can more or less confidently predict that, over the coming decades, many of these tailings piles will wash away, slowly but relentlessly, fanning out into the region’s agricultural landscape.

Once these heavy metals and flecks of uranium have dispersed into the soil, silt, and even plantlife, they will be nearly impossible to re-contain; this will have effects not just over the span of human lifetimes but on a geological timescale.

Second, most of these piles are unguarded: unwatched, unmonitored, unsecured. They contain radioactive materials. They are in a region known for rising religious extremism.

Given all this, surely finding a solution here is rather urgent, before these loose mountains of geological toxins assume an altogether more terrifying new role in some future news cycle—at which point, in retrospect, articles like The Economist‘s will seem oddly understated.

[Image: Hand-painted radiation sign at Chernobyl, via the BBC].

Indeed, our ability even to comprehend threats posed on a geologic timescale—let alone to act on those threats politically—is clearly not up to the task of grappling with events or landscapes such as these.

To go back to Robert Macfarlane, he wrote another article earlier this year about the specialized vocabulary that has evolved for naming, describing, or cataloging terrestrial phenomena. By contrast, he suggests, we now speak with “an impoverished language for landscape” in an era during when “a place literacy is leaving us.”

As Macfarlane writes, “we lack a Terra Britannica, as it were: a gathering of terms for the land and its weathers—terms used by crofters, fishermen, farmers, sailors, scientists, miners, climbers, soldiers, shepherds, poets, walkers and unrecorded others for whom particularised ways of describing place have been vital to everyday practice and perception.”

Channeling Macfarlane, where is the vocabulary—where are our cognitive templates—for describing and understanding these landscapes of long-term danger and slow catastrophe?

It often seems that we can stare directly into the wasteland without fear, not because there is nothing of risk there, but because our own words simply cannot communicate the inevitability of doom.

Hadean Transport

Greenpeace has released these images of a train carrying nuclear waste through Valognes, France. Shot with infrared film, the photos show a demonic red glow coming from inside the bellies of the railcars.

[Images: Via National Geographic].

“The train is hauling a so-called CASTOR convoy,” National Geographic explains, “named after the type of container carried: Cask for Storage and Transport Of Radioactive material. These trademarked casks have been used since 1995 to transport nuclear waste from German power plants to France for reprocessing, then back to Germany for storage.”

I’m reminded of a short video shown last week at the Landscape Futures Super-Workshop here in Los Angeles.

Produced by Smudge Studio/Friends of the Pleistocene, the film shows us a flatbed truck carrying transuranic nuclear waste along a desert highway. As Smudge write, “Our brief passing of this truck was a momentary point of contact with this waste, bound for deep time.” Filmed in sepia-toned Super-8, the 35-second film has a timeless and dramatic surreality, verging on postapocalyptic.

I should add, briefly, that the name of the train seen in the first three images—a CASTOR convoy—lends all of this a nicely symbolic overtone. In Roman mythology, Castor and Pollux were twin brothers; Castor was mortal, Pollux immortal, and it should come as no surprise to learn that Castor is eventually killed.

However, in one version of the story, “Castor’s spirit went to Hades [Hell], the place of the dead, because he was a human. Pollux, who was a god, was so devastated at being separated from his brother that he offered to share his immortality with Castor or to give it up so that he could join his brother in Hades.” I mention this otherwise superficial overlap because Smudge’s notion that nuclear waste is on its way to being entombed in “deep time,” far below ground, takes on explicitly Hadean resonance when put into the context of something called a CASTOR train.

(Related on BLDGBLOG: One Million Years of Isolation: An Interview with Abraham Van Luik and Fossil Reactors).

Ghosts Of The Future: Borrowing Architecture From The Zone Of Alienation

[Image: From Stalker, directed by Andrei Tarkovsky].

[Note: This is a guest post by Jim Rossignol].

During the period in which 3D videogames began to use textures imported from photography, rather than hand-drawn pixel tiles, it became common to hear game developers discuss their photo references.

Drew Markham, director of Return To Castle Wolfenstein, spent the 2001 pre-release press tour for his game talking about the time he had spent in Europe, sourcing textures from “real” locations that had played host to the war. Crumbling French flagstones, Teutonic concretes, and other useful built surfaces: these details would add a certain level of authenticity that other games lacked. When the Wolfenstein sequel finally arrived, British gaming journalists were amused to see the ubiquitous British “H” fire hydrant signs scattered deep within the occult bunkers of Himmler’s SS Paranormal Division.

[Image: Photo by Jim Rossignol].

A few years later, another photo-reference tour was being cited for the gaming press, only this time it was not a cheery holiday in Europe, but a trip to the Zone Of Alienation. This 30km area of Ukraine and Belarus remains poisoned and largely off-limits to mankind, thanks to the radioactive caesium that dusted it after the explosion at the Chernobyl Nuclear Power Plant in 1986.

While it has remained quarantined and closed to (legal) habitation, it hasn’t kept out sight-seers. The production team at GSC Gameworld, a games studio based in nearby Kiev, intended to use the derelict zone as the basis for environments in their action shooter, STALKER: Shadow Of Chernobyl. The team went into the zone and photographed urban dereliction: a snapshot of an abandoned Soviet Union. They would go on to fill their game world with the zone’s rusting fences and collapsing grain silos, but that was not all that came with the material: the landscape and its decaying architecture was already charged with mythology—with narrative.

Creative director Anton Bolshakov explained this in an interview in 2007: “The Soviet system was sealed, many facts were kept secret. Even the most harmless objectives or events generated unbelievable rumours and legends.” One example, he says, is

an existing gigantic antenna located within the Chernobyl exclusion zone. On some of our photos taken during the trip to Chernobyl the body of the antenna is seen on the horizon spanning several hundred meters across. So some unofficial sources claim, the waves emitted by the antenna were psychoactive. The antenna was directed onto Western Europe and preoccupied with a long-lasting military experiment on psychotropic influence onto human psyche.

[Images: The “steel giant” near Chernobyl; all photos via English Russia].

The antenna wall—actually an early-warning radar system developed for Cold War defense, which has been preserved thanks to being inside the zone—made it into the game as “the brain scorcher,” a device that must be shut down before the player can progress into the abandoned city of Pripyat. The environment of Chernobyl not only provided the game with an authentic atmosphere, it was also to influence the events that players could experience.

[Image: The “brain scorcher,” via Jim Rossignol].

However, the zone as an idea already existed before the explosion in 1986. It appeared, for instance, in a 1972 science fiction novel called Roadside Picnic. A mysterious, contaminated pocket of landscape, quarantined from the outside world, was the main theme of that book, which was written by two brothers, Boris and Arkady Strugatsky.

In the Strugatsky’s book, an alien visitation to the earth—an extra-terrestrial “roadside picnic”—has left dangerous and incomprehensible materials strewn across a zone of Northern Canada. Although sealed off for scientific research, this zone is raided by “Stalkers” who sell the unnatural trinkets for black-market cash. To do so, they brave bizarre dangers, because the zone has been transformed into a place that is utterly at odds with our own world. The alien is never seen or even described, and all the characters encounter is its terrible remainder: landscape made alien. Pools of jelly that will cripple a man lurk in basements, extra-terrestrial cobwebs that can stop a heart beating are strung across doorways, and gravitational mantraps will crush anyone who passes over the wrong patch of mud.

The zone of Roadside Picnic was seen by many as an allegory for the entire Soviet experiment: not simply in the literal sense of the poisoned landscapes created by the industrial excesses of the region, but the entire social order that was created by the Communist government. Polluted expanses, continually washed by acid rain, became shorthand for describing the bizarre political situation of a country in which Communism had failed, and yet robotically continued.

Russian film-maker Andrei Tarkovsky shot a movie, called Stalker, which told a story based on that of Roadside Picnic. A glacially slow, almost event-free film about landscape and longing, it’s a work that lingers for long minutes over broken wastelands of abandoned industry. It encapsulates Tarkovsky’s style, as well as his interest in dereliction and decay—themes that would be revisited by the STALKER videogame, thirty years on.

[Image: From Stalker, directed by Andrei Tarkovsky].

Tarkovsky’s film manages to imbue derelict industrial landscapes with a terrible sense of threat. Largely unable to realize the alien properties of artifacts in Roadside Picnic, Tarkovsky projected the danger into the architecture itself. Passive landscapes that could swallow a man. Tunnels which tear them to shreds. These effects were never demonstrated, but also never doubted, thanks to the tentative way the actors explored their surroundings.

In much the same way that the images of the real Chernobyl zone seem like lush vegetative scenes, despite being formidably radioactive, so Tarkovsky’s zone is calm and invisibly dangerous.

Cinematic legend had it that the power station shown in the final background scenes of the film was in fact Chernobyl NPP, although the truth is the entire film was shot in Estonia. That’s not to say that Stalker was without poisonous consequences of its own, however. The first version of the movie was shot entirely on corrupted film, which was unsalvageable when Tarkovsky’s production team returned to their Russian studios. Worse, the second shooting took place down stream from a poorly regulated chemical works. The effluent from the plant was responsible for many of the astonishing visuals in the river scenes from the movie, but team members came to suffer serious side-effects from this exposure, including cancer. They had, it seems, suffered side-effects from their time in the zone: just like the fate of the fictional Stalkers in the Strugatsky books. It was as if the fiction and reality were blurring back through each other. As if—to quote Alan Moore—the written page was too fragile a boundary.

Or perhaps, as Steven Shaviro suggests in his book Connected, Roadside Picnic, like all science fiction, actually exists to cast a shadow over the present. “It shows us how profoundly haunted we are by what has not yet happened,” says Shaviro of science fiction writing. In the specific case of Roadside Picnic and Tarkovsky’s film, what had not happened yet was the Chernobyl disaster.

After 1986, however, there were others for whom the ideas of Roadside Picnic were to be immediately accessible and useful in describing the world that they faced. People going into the Chernobyl exclusion zone, to loot buildings or show tourists around, began to call themselves “Stalkers.” For them, the zone of the Strugatsky’s vision was immediate and first-hand, a kind of fictional reference for the reality they were facing. They were living it—and it was strangely convenient to have the Stalker nomenclature to hand.

[Images: STALKER game images from this very extensive Flickr set].

As for Bolshakov and his creative team, borrowing from both the Strugatskys and the real world has proven fruitful. Real world ruins seem to connect with players far more readily than their fantasy counterparts. No one has been able to come away from STALKER without talking about the architectural waste that GSC borrowed from the zone. The game has now reached three iterations and supports an energetic fan community.

Bolshakov suggests that there is more to this than simply commerce or escapism, however: “The motif behind STALKER was to create a game which would remind people of the Chernobyl accident and at the same time warn mankind against any possible fatal mistakes in the future.” The warning seems likely to go unheard, but perhaps it has another message: to tell game developers that the architecture of the real world comes prefixed with meaning. Even now, when cities can be raised procedurally from the blank canvas of a game engine, perhaps it’s worth taking a look at the real world and the mythology that has been strewn around it. If borrowing architecture from the zone proves anything, it’s that simulation should not exist in a vacuum.

• • •

Jim Rossignol is a games critic, blogger, occasional guest writer on BLDGBLOG, and author of the excellent This Gaming Life: Travels in Three Cities, published by the University of Michigan Press. He is @jimrossignol on Twitter.

Fossil Reactors

There are as many as sixteen 2-billion-year old nuclear reactors in the rocks beneath Gabon. Considering their age, they are also, unsurprisingly, completely natural.

[Image: The natural clocks and ticking stratigraphy of the Oklo uranium deposit, courtesy of the Curtin University of Technology].

“In 1972,” the Curtin University of Technology explains, “the very well preserved remains of several ancient natural nuclear reactors were discovered in the middle of the Oklo Uranium ore deposit.” The university adds that each of these equatorial African reactors “operated on an intermittent basis for a period ranging from a few years to hundreds of thousands of years. The total time period over which the reactors operated is thought to be about a million years.”

In one specific case, we read in a report published five years ago by Physical Review Focus, a chain reaction in the uranium-rich rocks “cycled on and off every three hours.”

The idea that radioactive deposits beneath the Earth could self-react and undergo fission was first proposed by physicist Paul Kazuo Kuroda. The internal clock of a geological formation, Kuroda suggested, given contact with water, could simply start ticking away:

In 1956, nuclear chemist Paul Kazuo Kuroda of the University of Arkansas in Fayetteville predicted that a chain reaction could develop in natural uranium deposits, generating heat just as the reactor in a nuclear power plant does. His suggestion proved prophetic when, in the 1970s, others discovered several burned-out natural reactors in the Oklo uranium mines in Gabon.

Amazingly, “researchers still don’t know precisely how the fossil reactors managed to burn slowly for more than 150,000 years, when they could have exploded violently.” The presence of underground water seems especially fortuitous in that regard—it helped to avoid a nuclear detonation.

That’s plausible because the water molecules would collide with neutrons whizzing through the uranium and slow them down, a process called moderation. Because slower neutrons more efficiently split the uranium nuclei in a chain reaction, the water would promote the reaction and cause the reactor to heat up. Eventually, however, the heat would boil away the water, shutting the reaction down until more water could collect.

It was a pulsing rhythm, a geologic throb: based on present-day chemical measurements taken of specific isotopes in the nearby rocks, “the researchers estimate that the reactor ran for 30 minutes and then shut down for two and a half hours.”

[Image: A diagram of the Oklo uranium deposit, courtesy of the U.S. Department of Energy].

I’m reminded again here of William Burroughs’s extraordinary and haunting suggestion, from his novel The Ticket That Exploded, that, beneath the surface of the earth, there is “a vast mineral consciousness near absolute zero thinking in slow formations of crystal.” Here, though, it is a mineral seam, or ribbon of heavy metal—a riff of uranium—that stirs itself awake in a regularized cycle of radiative insomnia that disguises itself as a planet. Brainrock.

Gabon’s “natural nuclear fission reactors,” according to Wikipedia, “are the only known sites in which natural nuclear reactors existed. Other rich uranium ore bodies would also have had sufficient uranium to support nuclear reactions at that time, but the combination of uranium, water and physical conditions needed to support the chain reaction was unique to the Oklo ore bodies.”

Of course, this process created what we would now call nuclear waste—including plutonium. These otherwise extraordinarily dangerous waste products, however, have been entombed within the earth for two billion years. The Curtin University of Technology points out that “this is so long that all of the radioactive waste products (even those with million year half lives) have decayed away.” They have also hardly even moved: the plutonium, according to the U.S. Department of Energy, “has moved less than 10 feet from where it was formed almost two billion years ago.”

Are there thus structural lessons to be learned from the rocks at Oklo? “By analyzing the remnants of these ancient nuclear reactors and understanding how underground rock formations contained the waste, scientists studying Oklo can apply their findings to containing nuclear waste today,” the DOE goes on to suggest. This is another way of saying that the Oklo uranium deposits are being studied as natural analogues for how high-level nuclear waste might behave in an artificial repository like Yucca Mountain (watch for a long and fascinating interview with a geophysicist from Yucca Mountain here on BLDGBLOG next week).

We might say, then, that a geological formation, like some nuclear version of Spanish architect Vicente Guallart’s notion of geologics, has partially inspired an architectural form.

The timescales are all wrong for this, meanwhile, but if geomythology is the study of ancient folk tales, oral traditions, and regional myths to see if they contain camouflaged references to real, but prehistoric, geological events—earthquakes, tsunamis, volcanic eruptions, and more—what geomythological influence might the throbbing and automechanized Oklo uranium mines play? How extraordinarily interesting would it be to come across a series of old myths about an intelligent presence in the rocks of equatorial Africa, a kind of mineralized Mother Nature winking at everyone from below—and to realize that they’re referring to the reactions at Oklo. A spirit in the Earth.

Finally, do these naturally occurring reactions come with the implication that our present-day nuclear reactors are, in a sense, simulated geological processes, not unlike artificial diamond-creation chambers? Nuclear reactors become models of already existing natural events. They are terrestrial reenactments, you might say.

Scientific American has a five-page article about the Oklo phenomenon, if you’d like to read more.