A letter by Wing and his colleagues was published in the same issue of the journal, sweeping aside Susser’s assertions that the UNC team had caused a “brouhaha.” Instead, the letter called for a scientific discussion based on the facts, not name-calling:
We gave attention to residents’ reports of acute symptoms, acknowledged the history of secrecy and incompletedisclosure of radiation releases in the nuclear industry, and considered other supporting evidence of high level radiation assembled by plaintiffs in the civil suit… It is unfortunate, if not tragic, that so many questions remain eighteen years after the accident.
The UNC team’s concern over lingering Three Mile Island questions were never put to rest. Several years later, researchers from the University of Pittsburgh published two journal articles agreeing with the Columbia group’s “no link” conclusion for the 32,000 people living within five miles of the plant. But the Pittsburgh team also received funds from the industry-supported TMI Public Health Fund; only used data on cancer deaths, not cases; and only used data after 1979, not before the meltdown. No other attempts were made by researchers to examine hard data on cancers near Three Mile Island. To this day, the issue of how many casualties were caused by the meltdown remains an open one, empowering many to use the phrase “nobody died at Three Mile Island” and the broader “nobody ever died from American nuclear power plants.”
The notion that only people living within ten miles of Three Mile Island may have been harmed needs reassessment. An article in the journal Science showed that airborne levels of xenon-133, a fission product created in nuclear weapons tests and nuclear reactors, was three times above normal in Albany NY, 250 miles northeast of the plant, for five days after. Xe-133 decays quickly, with a half life of 5.3 days. It is clear that the prevailing winds brought the greatest radioactive plume from Three Mile Island towards the north and east.
Because the fetus is most vulnerable to radiation, it is logical that trends in infant deaths (especially those who died in the first twenty-eight days of life) before and after Three Mile Island be examined. Comparing rates just before and after the accident (1977–78 and 1979–80) shows increases for fourteen of nineteen Pennsylvania counties to the north and northeast of the plant, compared to just nine of the other forty-eight counties in the state (below).
Source: National Center for Health Statistics, Vital Statistics of the United States, Annual Volumes, 1977–1980.
On May 15, 2009, a notice abruptly appeared in the federal register. “The NRC is conducting a study to provide contemporary information on risk of cancer in the vicinity of nuclear plants,” it read. It announced that a Request for Proposals to conduct the study would be forthcoming within fifteen days, and that the winning bidder would be expected to take two years to complete the study.
The reason why the federal government finally decided to act, nearly twenty years after the first cancer study was completed, is a mystery. Four months before the federal register notice, RPHP Board members Joseph Mangano and Robert Alvarez had visited the staffs of Senator Edward Kennedy and Representative Edward Markey, asking that a new cancer study be conducted, by a source independent of government and industry. Whether these visits prompted the NRC to act is anyone’s guess.
The NRC was hardly an objective party to any cancer study, as it was staffed by former workers for nuclear utilities and received most of its funds from industry fees. It also had no health experts on its staff, yet it quickly selected the Oak Ridge Associated Universities (ORAU) to conduct the study. ORAU was a group of professionals tied in closely with the Energy Department-operated nuclear weapons complex in the town of Oak Ridge, TN. They were seen by many as leaning decisively towards the belief that nuclear reactors were operating safely, and not linked with cancer risk. Moreover, many of the ORAU members were nuclear engineers and physicists, not physicians or epidemiologists. The outcry from anti-nuclear activists quickly reached Capitol Hill, and in December 2009, fourteen signed a letter to NRC Chair Gregory Jaczko outlining their concerns about what should be included in a well-performed study.
The embarrassed NRC quickly reversed itself by dropping the Oak Ridge group, and replacing it with the National Academy of Sciences (NAS) Nuclear Radiation and Studies Board to conduct the study. While this looked like an improvement on paper, there were similar problems of objectivity and a pro-nuclear slant. The Board’s Chairman was former NRC chair Richard Meserve; he recused himself from the study, but the appearance of an overly cozy relationship between the NRC and NAS was obvious. Of the nineteen members of the Board, only five had health and medical credentials, most of the remainder being physicists or nuclear engineers. Not a single Board member had ever published any study on cancer near nuclear plants.
In 2010, the NRC held public hearings on the cancer study. Among those testifying was UNC professor Steve Wing, the lead author of the Three Mile Island studies. In April 2012, a NAS panel issued a feasibility report on what would be involved in a radiation-cancer study; a completion date would probably be 2014 or later, and there is speculation that the study may never take place. Despite the fact that a new study was under way, there were a number of lingering concerns, both methodological and political, that a repeat of the “no risk” conclusion of the 1990 NCI study would be reached as a formality. Some suspected that this was merely a tool for industry and government to promote an expansion of nuclear power.
The history of understanding and publicly sharing unsafe practices at US nuclear power plants has been a long and rocky one. The initial dynamics of the 1950s pitted industry and government promoters of nuclear power making assurances of safety against those skeptics(scientists, citizens, media, and public officials) who dared challenge this assumption and demand evidence of practices and outcomes. Over half a century later, this match-up has hardly changed, even though evidence of harm has slowly but surely accumulated.
Danger Now, Danger Tomorrow, Danger Forever
In the most general sense, radioactive waste refers to chemicals that are radioactive but have no further use after being created. While all radioactive waste is dangerous and necessitates actions to keep humans and other living organisms from being exposed to it, the type of radioactive waste that is the focus here is that produced at the end of the nuclear fuel cycle, i.e., uranium mining, milling, enrichment, and fabrication. These chemicals are produced in reactors, and constitute the most plentiful and most dangerous of all the types of waste already mentioned. They are commonly referred to as high level waste by experts. In order to generate energy, reactor operators place fuel rods into the reactor’s core. These rods, about twelve feet in length and the diameter of a pencil, are made of an alloy of the metal zirconium. They consist of uranium pellets about half an inch long that are stacked on top of one another inside the rods.
About 100 fuel rods are bundled together in what is called a fuel assembly. The rods do not touch one another so cooling water can flow between them. Hundreds of assemblies at a time are loaded into a steel chamber in a reactor’s core. Plant operators shoot neurons into the fuel rods, which results in the “fission” process (splitting of uranium atoms) and the resulting high heat that will be converted into steam, moved through turbines, and converted into electricity.
The process of splitting uranium atoms in the reactor core is the same as that when an atomic bomb explodes – with several exceptions. The uranium used in reactors is only about 3% pure (percent of U-235), compared to 95% in an atomic bomb. In addition, the fission in a nuclear reactor is regulated, or controlled. Hundreds of control rods made of boron or cadmium are also placed in the reactor core to absorb neutrons from the fuel rods, keeping the neutrons from doing any further damage. In an atomic bomb explosion, the fission process is not controlled.
Fuel rods are used for about twelve to eighteen months each, when their useful life ends. The old rods are replaced by new ones in a process called “refueling.” The reactor is shut down during refueling, as other maintenance is performed
during this time. The old rods, also known as “spent fuel rods,” are transferred into deep pools of cool water at the plant – stacked upright, with water between them so rods will not touch each other.
At this point, even though the fuel rods have no further use because the U-235 is used up, they are highly radioactive. When they are first retired and placed into the spent fuel pools, they consist of hundreds of radioactive chemicals in particulate form. These can be classified into four categories:
– Fission products, which are atoms created when the U-235 atom is split
– Actinides, which generally are heavy atoms that are created when U-235 atoms decay
– Fuel Impurity Activation Products, created from fuel impurities absorbing neutrons
– Zircaloy-4 Activation Products, created when the zirconium sheath around the rods absorbs neutrons
Storage of spent fuel actually begins in the reactor core, as the fission process generates electricity. Large volumes of radioactive waste products, in the form of particles and gases, are produced, and remain in the fuel rods as they continue to generate high heat to boil water after being bombarded with neutrons. Because it takes a long time for fuel rods to be used up, only every twelve to eighteen months are they removed from the reactor core during refueling.
Although a small portion of the enormous amount of radioactivity escapes into the environment, the large majority is contained within the rods in the core. The core, then, becomes the first storage area of high level waste. The key to keeping the radioactivity in the core from causing tremendous harm is cooling water. Any loss of cooling water will result in the core’s temperature reaching extremely high levels, typically about 3,400 degrees Fahrenheit – causing it to melt down, and release the high level waste into the reactor building, and possibly into the environment.
The concept of meltdown is far from fictional. Although power reactors are just under sixty years old, they have experienced a number of meltdowns. The largest, of course, was at Chernobyl in 1986, although the multiple meltdowns at Fukushima in 2011 may eventually rival Chernobyl. In the US, meltdowns at power reactors have occurred at the Idaho National Laboratory (1955 and 1961), Santa Susana CA (1959), Waltz Mill PA (1960), Fermi MI (1966), and Three Mile Island PA (1979). Repeated assurances by leaders that reactors are constructed and operated with such care that a meltdown is not possible have been proved untrue time and again. Actually, some leaders acknowledge that meltdowns are all too possible. In the late 1980s, just after the Chernobyl disaster, NRC Commissioner James Asselstine told a Congressional hearing there was at least a 45% chance that a fleet of 100 reactors would experience a core meltdown in twenty years, a chilling estimate given the current US fleet consists of 104 aging and corroding units:
Given the present level of safety being achieved by the operating nuclear power plants in this country, we can expect to see a core meltdown accident within the next twenty years.
The amount of radioactivity in a typical reactor core means the potential for causing harm to public health is enormous. The containment building where the core is located must not be penetrated, or a catastrophe will ensue. In the wake of the Three Mile Island accident and with public opposition to nuclear power growing, Congress asked officials at Sandia National Laboratories in New Mexico to calculate how many humans would be harmed in a worst case accident scenario.
In 1982, Sandia officials turned in their work to the House Committee on Interior and Insular Affairs. Results were shocking. The estimates of damage to humans were classified into several types. Immediate casualties included fatal and non-fatal cases of acute radiation poisoning, and long-term cancer deaths were also included. Calculations varied, but some were high, especially those near highly populated areas. For example, a worst case core meltdown at either of the two reactors at the Limerick plant (which was being built and had yet to start operating in 1982) would devastate the greater Philadelphia area. Within twenty miles of the plant, there would be 74,000 fatal and 610,000 non-fatal cases of acute radiation poisoning; and within fifty-five miles, there would be 34,000 fatalities from cancer in the long term. The sharp growth in local population in the thirty years since the Sandia study would raise these numbers considerably.
The report, Calculation of a Reactor Accident Consequences (CRAC-2), was published in the New York Times and Washington Post on November 2, 1982, the day after it was submitted to Congress. Some have criticized the report as too cautious; for example, acute radiation poisoning casualties were calculated at fifteen to twenty miles from reactors, and people living within fifty to sixty miles would die of cancer, while some believe a meltdown would cause harm to a much greater area. No other such estimate has been made since; and the increase in the US population from 226 million in 1980 to 309 million in 2010 would increase the casualties accordingly. The lesson for storing waste in the core is that high level waste released from the core in a meltdown would devastate human health. The table below lists the reactors with the greatest potential to cause harm.
Source: Sandia National Laboratories. Calculation of Reactor Accident Consequences (CRAC-2) for US Nuclear Power Plants. Presented to Subcommittee on Oversight and Investigations, Committee on Interior and Insular Affairs, November 1, 1982. Published the following day in the New York Times and Washington Post.
The harm caused by waste while it is still in the core is arguably most dangerous, as all radioactive chemicals – fast-decaying and slow-decaying – are still active. Long-term storage contains enormous amounts of radiation, but without the fast-decaying products, which have disappeared.
When fuel rods are “spent” or unable to produce any more electricity through fission, and fuel assemblies are changed during refueling every twelve to eighteen months, spent fuel rods are moved from the core into deep pools of water in the nuclear plant. These “spent fuel pools” are designed to be temporary storage facilities. They must maintain cooling water in them, or the possibility of a meltdown will become a reality.
In a relatively short period of time, a substantial portion of the radioactivity in spent fuel rods decay and disappear. Some of the chemicals in the rods have relatively short half lives, including xenon-133 (five days), iodine-131 (eight days), barium-140 (twelve days), and strontium-89 (fifty days). Some even have half lives measured in hours or minutes. A general consensus is that ten half lives are needed for a radioactive chemical to essentially disappear from the biosphere. But because of the enormous amounts produced in the reactor core, some short-lived products are still present in fuel rods for several years after they are retired.
Moreover, even after the fast-decaying chemicals disappear, huge amounts of many chemicals still remain. One accounting lists 211 separate radioactive chemicals that are still present in pools of spent fuel rods ten years after they are retired. These encompass radioactive forms of seventy-six of the elements that are found in any basic Periodic Table of the Elements, i.e., more than one radioactive isotope is present for some elements. For example, only one form of radioactive Carbon is present (C-14), while three forms of radioactive cesium are found in the pools (Cs-134, Cs-135, and Cs-137).
Some of these chemicals have relatively short half lives; Ruthenium-106 has a half life of one year. But on the other end, some chemicals have extremely long half lives (below):
Sources: US Nuclear Regulatory Commission: Radionuclides (10CFR Part 20, Appendix B. H (list of isotopes). Holden NE. Table of the Isotopes. In Lide DR. CRC Handbook of Chemistry and Physics (85th Edition). CRC Press, 2004.
Some of these chemicals on this list are not just man-made, but also found in nature, i.e., rhenium-187, thorium-232, uranium-238, uranium-235, iodine-129, lead-205, and hafnium-182. But the others are strictly man-made from atom bomb explosions and nuclear reactor operations. Many of these are not necessarily the most harmful, as the very slow decay rates mean only a small amount of radioactivity will be released in a given time. But they still pose harm to humans and other forms of life, and wil
l be on the planet forever.
Faster-decaying chemicals making up high level waste will not last forever, but are more radioactive, as shorter half lives mean faster decay rates, and greater exposures. While all radioactive chemicals in waste are harmful, some are more toxic than others. One of these often cited is plutonium-239, an especially deadly chemical made more dangerous because it is used to trigger atomic bombs.
High level radioactive waste must be stored safely away from all forms of life – forever. Just a single flub in storage could result in enormous suffering, due to the large amount of waste involved. And experts have yet to agree upon a single solution, over sixty years since the atomic age began.
As of 2012, there are roughly 68 million metric tons of radioactive waste stored at US nuclear power plants, a number that increases by about two million each year and that greatly exceeds that at any nuclear weapons plants. The 68 million metric tons are contained in over 200,000 fuel assemblies with over two million spent fuel rods. Because this waste is spread across eighty-two locations across the US, some sites contain well over one million metric tons. The waste contains 11.8 billion curies of radioactivity, most of it cesium-137, plutonium-241, and strontium-90.
Mad Science: The Nuclear Power Experiment Page 16
