by Bill Fawcett
However, the transporting of animals from one ecosystem to another does not always go according to plan—in fact, it might be stated that it never goes according to plan. The introduction of rabbits, as pets and food, to Australia backfired when the cute little bunnies (who have a rather well known penchant for reproduction) virtually overran the land Down Under. The Everglades in south Florida are being infested with pythons and other constrictors that are not native to the area. Apparently a large number of Floridians eventually decide that their pet snake has grown too big to keep, so they release it into the wild where it proceeds to devour any and all local fauna, none of which has evolved to regard these snakes as natural predators.
You’d think we would learn, but no, not us humans. Take the carp, for example. These large and prolifically breeding fish have been domesticated in China for more than a thousand years. Some breeds of carp were imported to the United States during the 1800s. Large, fast-growing, capable of eating just about anything, they took hold in many bodies of fresh water. Regarded by some as at least tolerably edible (at least, after smoking the meat) they are considered by others as merely a nuisance fish. Still, they have been around for more than a hundred years, and have become a fixture in many American lakes, ponds, and rivers.
Yet it is a different carp that is at the root of a new and very real problem currently menacing the Great Lakes—the largest fresh-water eco-system in the world. During the 1970s, two new (to America) breeds of carp were imported in small numbers by the operators of fish farms in the south, especially in Arkansas and adjacent states. Bighead and silver carp were brought in because they serve a useful economic function: they essentially worked as organic filters, cleaning the water of the fishponds by feeding on algae and absorbing other suspended matter.
They did their work well, too, and the presence of these large carp aided the operators—most of whom raised catfish—in keeping their water clean and enhancing the efficiency of their farming operations. Things hummed along pretty well for about fifteen years. Less well known, but accurately documented, are efforts by the federal government to use these same fish to help clean up sewage containment ponds (clear evidence that the fish can survive in some really polluted water!). Small numbers of the exotic carp were transported throughout the south by federal wildlife and natural resource management officials. As in the catfish ponds, the carp not only survived, they thrived. They did their work well, and reduced the use of chemical treatments required. All in all, it seemed like a win-win situation.
During the 1990s, however, a series of catastrophic floods swept through the areas where the fishponds had been established. The farmers faced tremendous losses, but so did the environment of the whole Mississippi River system: the floodwaters carried away the borders around the fishponds, and introduced bighead and silver carp to the wild. Those fish liked the waters of the Mississippi and its tributaries—they liked them a whole lot. So much so that they have already overwhelmed many of the native fish in the Big Muddy, with devastating effect on a large number of fish-based economies.
Carp eat voraciously—up to twenty percent of their body weight in plankton, daily—and they breed with similar enthusiasm, females carrying as many as five million eggs at a time. They can grow to up to a hundred pounds, and lengths of four feet. As they continue to expand their range, they have moved northward through the Mississippi and into important tributaries including the Missouri, Ohio, and Illinois Rivers. There is every indication that the carp invasion will continue up the adjacent waters until the exotic, imported carp have taken over the rivers, exterminating or endangering countless species of native fish.
Although their consumption of plankton—which is at the base of the food chain for virtually all aquatic species—is a massive threat, the carp are not just deadly to fish and the fishing industry. An unusual, and dangerous, trait of the silver carp has rendered them a menace to the sport-boating industry, as well. It seems that the fish panic when the waters are disturbed by a loud, unnatural sound like, say, the rotating propeller of an outboard motor. The fish’s reaction is to fling itself upward, out of the water, sometimes as high as ten feet in the air. When a twenty-pound fish leaps into the air directly in the path of a speeding motor boat, Jet Ski, or water skier, the resulting collision is a bruising experience, or worse.
The silver carp have become so thick along one stretch of the Illinois River that the area’s whole culture has changed. People who grew up using the river as a primary focus of recreation are now pulling their boats out of the water and keeping their kids on dry ground. A U.S. Fish and Wildlife biologist who patrols the river has had a protective cage placed around the pilot’s station of his boat, and is thinking about getting lacrosse helmets as protection for his crew. A fisherman who, a decade ago, might collect 5,000 pounds of native buffalo fish recently reported a haul of more than 6,000 pounds of bighead carp, and only one single buffalo.
Nature has divided the Great Lakes and the Mississippi Basin into two separate watersheds. A subcontinental divide extends from Minnesota through Wisconsin, Illinois, Indiana, Ohio, and eastward, dividing the drainage from rainfall and snowmelt. Water from north and east of the divide flows into the Great Lakes and, eventually, out the St. Lawrence River. Water falling south, or west, of the divide runs eventually into the Mississippi and the Gulf of Mexico, often through important tributaries such as the Wisconsin, Illinois, and Ohio Rivers. Such watershed divides are, and have always been, facts of nature.
But once again the hand of man has set foot upon Mother Nature’s neck. With the support and funding of federal and state governments, the Chicago Sanitary and Ship Canal was created long ago as a boon to business interests. The manmade channel is still used by lots of barges, carrying goods ranging from coal to timber to food. And—you guessed it—it connects the two watersheds, joining the Chicago River, which flows into Lake Michigan, to the Illinois River, which of course flows into the Mississippi.
Right now, the bighead and silver carp have advanced up the Illinois River to within 50 miles of Lake Michigan. That huge body of fresh water, with its easy connections to the rest of the Great Lakes system, would be an environmental paradise for the carp. However, it is currently a financial and sporting paradise for millions of boaters, as well as sport and commercial fisheries. The activities of all of these users are drastically threatened by the imminent invasion.
The federal government, as well as the various affected state governments, have begun to take notice. However, the canal is still too useful, and too integral a part of the existing industrial infrastructure to consider filling it in. Instead, the feds have come up with a different plan, an electric barrier across the canal. A series of cables are used to charge the water with a jolt of electricity that, in theory and through testing, has been show to turn back migrating fish. The plan—or at least, the hope—is that this barrier will prove impermeable to fish, and will hold the invasive species out of the vast freshwater treasure of North America.
However, like so many inventions of humanity, this plan that, admittedly, looks good on paper, has already demonstrated some weaknesses. It was completed and intended to be activated in 2005, but two years later federal engineers are still trying to work out the bugs. It seems that the barrier electrifies a lot more of the water than previously imagined, and this has raised concerns about the safety of barge workers who would potentially have to unload coal in an area of sparking, charged water. Sparks have also flown from barges in transit, and the potential arc between a metal hull filled with coal and one carrying gasoline doesn’t have to be spelled out to be frightening.
Furthermore, the power supply that would maintain the electrical barrier is subject to the same vagaries as the power supply of the rest of the Midwest. While it is generally reliable, the existence of tornadoes, ice storms, and, yes, floods, can all create interruptions in the supply. If the power fails, and a few exotic carp—carrying five million eggs apiece—meander up the canal and in
to Lake Michigan, the results, and the resulting catastrophe, are not too difficult to imagine.
“Your safety is our business.”
—Motto of Atomics International (as seen blazoned on the clothing of employees peering into the reactor core)
Overcooking with Atoms
Teresa Patterson
The third worst nuclear disaster in history began as a brilliant plan to create clean, cheap energy without fossil fuels. In April of 1957, unknown to most Americans, the Sodium Reactor Experiment came on line at the Santa Susana Field Laboratory, 30 miles north of Los Angeles, California. The SRE was only one of ten nuclear reactors located at the SS Field Laboratory, but it was the most powerful, at 20 megawatts, and the only one designed to provide energy for civilian use. On July 12, 1957, the SRE, built and run by the Atomics International branch of Rocketdyne, began feeding energy to the power grid, becoming the first commercial nuclear power reactor in the United States. At the time, one Los Angeles paper proudly proclaimed, “L.A. Housewives Cook with Atom.”
For more than two years the SRE supplied power through Southern California Edison to over 1,100 homes in the Moorpark area of Ventura County. Then in 1959 that same plant malfunctioned, causing the third worst—and least known—nuclear accident in the world, after Chernobyl in the U.S.S.R. and Sella-field in Britain but well before Three Mile Island.
After World War II, scientists were determined to harness the power of the atom for peaceful purposes. In the mid fifties, the Atomic Energy Commission began a Five-Year Reactor Development Program authorizing the design and construction of a number of nuclear reactors. The most common type, the water-cooled reactor, used uranium rods as the fuel source, controlling the reaction with water. But water reactors eventually consume the uranium fuel and must be re-supplied. At the time, fuel grade uranium was quite rare. The AEC knew that existing supplies would not be sufficient to fuel all of the reactors in their plan. They were also concerned about the difficulties involved in disposing of spent fuel. They needed a different kind of reactor.
Cooled by liquid metal instead of water, the SRE, a graphite-moderated, liquid sodium metal cooled power reactor, represented an innovative solution to the depletion problem, and an evolution in reactor design—at least on paper. Sodium reactors never deplete their fuel supply, so the SRE could—theoretically—provide uninterrupted power without any need for additional uranium. It was therefore vastly more efficient than a comparable water-cooled reactor.
Unfortunately, molten sodium is also vastly more dangerous than water. It burns in the presence of air and explodes in the presence of water. To prevent air contamination, the SRE design included a barrier of helium enveloping the reactor core. To prevent water contamination, the pumps that circulated the liquid sodium through the core were lubricated with tetralin, an organic chemical. However, since the SRE was “experimental,” the one thing it didn’t have was a protective shield. The Atomic Energy Commission did not require experimental reactors to have an external containment structure. Unlike Three Mile Island, with its heavy reinforced concrete domes, the Sodium Reactor Experiment resided in a common industrial building. The design included holding tanks to capture any escaping radioactive gases—but the holding tanks vented into open air. It was assumed that the delayed discharge from the holding tanks and the remote location of the facility would provide adequate protection.
But such optimistic design parameters were not the reactor’s only flaw.
On July 13, 1959, during regular operations, the temperature and radiation readings on the SRE suddenly spiked. Technicians fought to shut the reactor down as readings skyrocketed—indicating the reaction was out of control. After considerable effort they managed to shut it down, but no one could explain why they had experienced the sudden “power excursion.” The technicians carefully inspected the reactor—for about two hours. After that very basic inspection they still had no idea what had happened—so they did what Homer Simpson would do—and turned the reactor back on.
In true Simpsons fashion, Atomics International continued to operate the SRE, despite major temperature and radiation fluctuations, for two more weeks—until July 26, when radiation levels and other signs of major trouble escalated to the point that the scientists could no longer ignore the problem. They finally decided to shut the reactor down and get to the bottom of the situation.
During the next, much more thorough, examination, technicians dropped a camera into the reactor core and found the bottom—literally. Thirteen out of forty-three fuel rods had melted and fallen to the bottom of the reactor chamber. The core had been in the process of melting for fourteen days—the longest nuclear accident in history.
The scientists discovered that a leak in the pump seals caused the accident, allowing tetralin to leak through the seals into the molten silicon and then into the reactor core. Of course tetralin had been chosen as a lubricant because it didn’t react with liquid sodium. But no one thought to test it inside a reactor.
Once in the core, neutron bombardment caused a change in the tetralin, turning it from a liquid into a gluey tar-like substance, eventually creating a build up of carbonaceous material that blocked coolant channels around the fuel rods. Without coolant, the fuel overheated, and eventually melted. By the time the reactor was finally shut down, one third of the fuel had been damaged.
The melting process released radioactive by-products that breached the helium layer, entered the holding tanks, then, over the course of weeks, vented into the environment. The actual extent of the release is unknown, though some monitors in use at the time went off the scale. While no reliable measurements were taken from the liquid sodium, ratios of volatile radio nucleotides found in the coolant suggest the release was significant.
The actual SRE accident was only about one one-hundredth the size of that of Three Mile Island, but experts estimate that the SRE accident released between 260 to 459 times as much radiation, making it the worst nuclear disaster in the United States. Without Three Mile’s concrete containment domes, there was nothing to stop the resulting radiation from escaping directly into the air.
In October 2006, a special advisory panel of scientists and researchers from across the U.S. concluded that the cesium-137 and iodine-131 that escaped may have caused as many as 1,800 cancer deaths among workers at the facility and civilians in the surrounding area.
Today sodium-graphite reactors are running or under construction in many parts of the world, some of them with long and successful work histories—but all of them are designed with containment shields. It is to be hoped that they also use a different pump lubricant—and have smarter technicians.
“Whoever concerns himself with big technology, either to push it forward or to stop it, is gambling in human lives.”
—Freeman Dyson
Contamination in the Hills
The Santa Susana Field Laboratory
Teresa Patterson
Near the close of World War II, Werner von Braun’s V2 rocket made a profound impact on the world as it streaked through the skies on its mission of destruction. Von Braun’s rocket inspired future generations to reach for space, heralding the beginning of a global race for military and technological superiority that continued into the cold-war era and culminated with a drive to control the heavens. After the U.S.S.R. shocked the world with the launch of Sputnik in 1957, the drive to attain a foothold in space reached frenzied proportions, especially in America. The U.S. soon dominated the resulting “Space Age,” demanding more and greater advances in aerospace, nuclear, and military science. Even ordinary citizens were caught up in the excitement of the quest to reach the moon. Companies such as the Rocketdyne division of North American Aviation took up the challenge, developing rocket engines, military systems, and even nuclear power reactors to quench the hunger to go higher, faster, and stronger—eventually sending American astronauts to the moon on the backs of their mighty Vanguard rocket engines, as well as putting the first nuclear reactor in space.
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World War II also revealed the terrifying power of the atom. The U.S. proved it could use nuclear power for war, but the aftermath of the war launched a desperate desire to harness the atom’s awesome energy for peace. Rocketdyne’s subsidiary, Atomics International, joined the elite list of companies working with the government to make that dream a reality.
Of course rockets do not leap wholly formed onto their launch pads, and splitting the atom—especially when you don’t want an explosion—is tricky stuff. Rocketdyne needed a place large enough to build and test rocket engines along with the new fuels to drive them, and remote enough to allow cutting edge nuclear research—since they intended to conduct work too dangerous for a populated area. In 1947, they chose a site with over 2,500 acres of wilderness high in the Santa Susana mountain range. It fit the plan perfectly. Situated between the Simi and San Fernando Valleys, it was remote enough to keep secrets, but not too far from the Rocketdyne headquarters in Canoga Park, California.
Both NASA and the Department of Defense were thrilled at the prospect of testing new munitions and propulsion systems, while the Department of Energy saw the new lab as the perfect place to explore the energy potential of the atom. At the time, it didn’t seem to matter that the site was only thirty miles from Los Angeles—one of the most densely populated cities in the country. All that mattered for the government and Rocketdyne—and for much of the country for that matter—was success at any price. No one had yet considered what that price would be.