Types and Sources of Radioactive Waste

Levels of Waste. How to dispose of radioactive waste depends on the degree of risk that it poses. Low-level waste (LLW) consists of such material as paper, rags, and tools that contain small amounts of mostly short-lived radioactivity. About 90 percent of the volume of all radioactive waste is LLW, but it accounts for only one percent of the total radioactivity. It does not require shielding and is often burned or compacted before disposal.

Intermediate level waste (ILW) is somewhat more radioactive and generates some heat. It includes such things as chemical sludges, metal fuel cladding, and contaminated materials from the decommissioning of reactors. It requires some shielding and may be solidified in concrete for disposal. About 7 percent of the volume of all radioactive waste is ILW, which accounts for about 4 percent of the radiation.

It is high-level waste (HLW) that must be treated with the most extreme caution. It produces so much heat while decaying that it requires both shielding and cooling. It is the product of burning uranium fuel in a reactor and may contain all the products that are created by fission. Although it accounts for only 3 percent of the volume, it emits 95 percent of the total radioactivity of all the waste and therefore it requires by far the most careful management.(1)

Background Radiation. Not all risks come from contact with “waste,” of course. Many fissile elements occur in small amounts in nature, and excessive exposure to them can be lethal. We are regularly exposed to small amounts of radiation by unknowingly contacting (mostly mildly) radioactive substances. We breathe a little radiation, eat it, and encounter it in other ways. These sources are considered normal background radiation. For example, radon is a gas that kills more people than drunk driving.(2) It is not a by-product of human activity but occurs in the natural environment and sometimes seeps into basements, causing cancer.

Background radiation also includes cosmic radiation, which mostly originates outside our solar system or even from distant galaxies. Upon impact with earth’s atmosphere, cosmic rays can produce showers of secondary particles that may scatter onto the ground. However, flying high in the atmosphere increases our exposure. Thus flying once across the North American continent exposes each passenger to almost as much radiation as from one chest x-ray. Natural background radiation exposure is about 1.8 millisieverts per year in Canada and 2.4 mSv worldwide.(3) We don’t worry much about it because living beings have always been exposed to some levels of background radiation, yet our species is still alive.

We are justified, however, in worrying about the additional exposure that pollutes our environment because of human use of radioactive materials in industry, medicine, nuclear reactors, and nuclear weapons.

These four technologies are named above in ascending order of risk to humankind. Clearly, nuclear weapons pose the worst of these threats and we must not overlook our exposure to its risks, not only during a nuclear war but also from the lingering radiation after such a war, or even from mere manufacture of the bombs. Unfortunately, most of the radiation left over from nuclear war and nuclear testing has been dispersed around in the environment in ways that make it difficult or impossible to clean up.

Ways of Disposing of Radioactive Waste

There is no good way of disposing of a substance that for hundreds of thousands of years will kill any living creature that contacts it. However, some methods are worse than others, and it is our duty to seek the optimum solution. Below is a short paper on the subject written by Subhan Ali in 2011.(4) In principle, all of these disposal methods can apply to military, medical, and industrial waste, but the current controversies only concern how to sequester the wastes from nuclear power plants. Ali writes,

“As part of the nuclear fuel cycle process, radioactive waste is produced that needs to be safely dealt with in order to avoid permanent damage to the surrounding environment. Nuclear waste can be temporarily treated on-site at the production facility using a number of methods, such as vitrification, ion exchange, or synroc.(5) Although this initial treatment prepares the waste for transport and inhibits damage in the short-term, long-term management solutions for nuclear waste lie at the crux of finding a viable solution towards more widespread adoption of nuclear power. Specific long-term management methods include geological disposal, transmutation, waste re-use, and space disposal. It is also worth noting that the half-life of certain radioactive wastes can be in the range of 500,000 years or more.(6)

“Geological Disposal

“The process of geological disposal centers on burrowing nuclear waste into the ground to the point where it is out of human reach. There are a number of issues that can arise as a result of placing waste in the ground. The waste needs to be properly protected to stop any material from leaking out. Seepage from the waste could contaminate the water table if the burial location is above or below the water level. Furthermore, the waste needs to be properly fastened to the burial site and also structurally supported in the event of a major seismic event, which could result in immediate contamination. Also, given the half-life noted above, a huge concern centers around how feasible it would be to even assume that nuclear waste could simply lie in repository that far below the ground. Concerns regarding terrorism also arise.(7)

“A noted geological disposal project that was recently pursued and could possible still be pursued in the future by the United States government is the Yucca Mountain nuclear waste repository. The federal government has voted to develop the site for future nuclear storage. Although the Obama administration stated that Yucca Mountain is “off the table,” Congress voted by a margin of 10 to 1 in 2009 to keep funding the project as part of the federal budget. A number of concerns surround this project and the ultimate long-term viability of it are yet to be seen given the political uncertainty surrounding it.(8)

“Reprocessing

“Reprocessing has also emerged as a viable long term method for dealing with waste. As the name implies, the process involves taking waste and separating the useful components from those that aren’t as useful. Specifically, it involves taking the fissionable material out from the irradiated nuclear fuel. Concerns regarding reprocessing have largely focused around nuclear proliferation and how much easier reprocessing would allow fissionable material to spread.(9)

“Transmutation

“Transmutation also poses a solution for long term disposal. It specifically involves converting a chemical element into another less harmful one. Common conversions include going from Chlorine to Argon or from Potassium to Argon. The driving force behind transmutation is chemical reactions that are caused from an outside stimulus, such as a proton hitting the reaction materials. Natural transmutation can also occur over a long period of time. Natural transmutation also serves as the principal force behind geological storage on the assumption that giving the waste enough isolated time will allow it to become a non-fissionable material that poses little or no risk.(10)

“Space Disposal

“Space disposal has emerged as an option, but not as a very viable one. Specifically, space disposal centers around putting nuclear waste on a space shuttle and launching the shuttle into space. This becomes a problem from both a practicality and economic standpoint as the amount of nuclear waste that could be shipped on a single shuttle would be extremely small compared to the total amount of waste that would need to be dealt with. Furthermore, the possibility of the shuttle exploding en route to space could only make the matter worse as such an explosion would only cause the nuclear waste to spread out far beyond any reasonable measure of control.

“The upside would center around the fact that launching the material into space would subvert any of the other issues associated with the other disposal methods as the decay of the material would occur outside of our atmosphere regardless of the half-life.(11)

“Conclusion

Various methods exist for the disposal of nuclear waste. A combination of factors must be taken into account when assessing any one particular method. First, the volume of nuclear waste is large and needs to be accounted for. Second, the half-life of nuclear waste results in the necessity for any policymaker to view the time horizon as effectively being infinite as it is best to find a solution that will require the least intervention once a long-term plan has been adapted. Last, the sustainability of any plan needs to be understood. Reducing the fissionability of the material and dealing with adverse effects it can have on the environment and living beings needs to be fully incorporated. Ultimately, nuclear waste is a reality with nuclear power and needs to be properly addressed in order to accurately assess the long-term viability of this power source.”

Before considering more fully the management of poisons produced by civilian nuclear power plants, we should consider an even more difficult problem: the effects of military nuclear waste.

Military Nuclear Waste

Nuclear Fallout. Only two nuclear bombs have been detonated for the purpose of killing a population: one in Hiroshima and the other in Nagasaki. However, about 2,000 other nuclear bombs have been exploded in tests, and some of the fallout from those conducted above ground is still coming down on us today. Many people have died as a result of such exposure, in addition to the Japanese “Hibakusha” who survived the two initial bombs. After a nuclear explosion, radioactive particulate matter is lifted to the stratosphere. This “fallout” may take months or decades to return to the earth’s surface, and may land anywhere in the world.(12)

Until 1963, the bomb tests were done above ground in Nevada, and thousands of workers were exposed to the deadly fallout, without understanding the gravity of the risks. According to research published in 2018, between 340,000 and 690,000 Americans died between 1951 and 1973 of the effects of radioactive fallout. Most of these effects came from cancer caused by drinking milk that had been contaminated from the tests.(13) Elevated atmospheric radioactivity remains measurable today from the widespread nuclear testing of the 1950s.(14)

Depleted Uranium. Another radioactive pollutant is depleted uranium. Natural uranium is usually “enriched” for use in nuclear power plants and bombs, and after the enriched portion is removed, the remainder is called “depleted uranium.” It is about twice as heavy as lead, which makes it useful for a few peaceful purposes, such as ballast in aircraft or keels of yachts. However, it has about 50 percent of the radioactivity of natural uranium, which means that it is also carcinogenic.(15)

Nevertheless, some armies use it for armor plating their tanks and their armor-piercing bullets and shells. After a battle, the environment may be littered with radioactive debris and even the radioactive burnt-out hulls of tanks. In Iraq, children later playing on the battlefield were exposed to radiation, and many U.S. soldiers complained after returning home from Iraq and Afghanistan of their own lasting health impairment. However, some studies have concluded that the risk is not as great as these protesters complain.(16)

Nuclear Submarines. In 1954, during a serious phase of the Cold War, the United States launched its first nuclear-powered submarine, the USS Nautilus. Soon thereafter the Soviets also developed more nuclear-powered subs than the US fleet. The vessels were ideally suited for remaining submerged for long periods, undetected and without coming up for air, and for their ability to launch ballistic missiles. By 1997, the Soviet Union (later Russia) had built 245 of them—more than all other nations combined. The other countries possessing strategic nuclear-powered submarines are France, the United Kingdom, China, and India. Brazil and Argentina are working toward acquiring their own such subs.(>17)

Although in 1963 the US was first to lose a submarine with a large crew — 129 persons — it is the Russian nuclear-powered submarines that have experienced the largest number and most serious of such mishaps. Their Kursk sank in 2000, losing the crew of 118.(18)

Every reactor that lies at the bottom of the ocean poses a risk of radiation pollution—some sooner than others. Apparently, the Soviet K-278 Komsomolets, which sank in the Barents Sea, is leaking plutonium from one of its torpedoes. Also, the cooling pipes of the reactor were broken. A repair mission solved some of the problem, but eventually it and all of the other sunken nuclear reactors will become a huge threat to large areas of the ocean.(19) There are now six nuclear submarines lying at the bottom of the oceans—four Russian and two American.(20)

Moreover, the dismantlement of nuclear submarines also poses a threat—especially in Russia. About 179 of those ships reached the end of their service life in the late 1980s and early 1990s and were retired. But dismantlement is expensive — up to $10 million per submarine. Almost half of the 183 decommissioned ones are still loaded with fuel—notably dozens of kilograms of U-235 and several kilograms of plutonium-239. These could be stolen.(21)

Another possibility is that, instead of scrapping them, Russia may sell the subs, and even the fuel, to another country. The Non-Proliferation Treaty does not require IAEA safeguards for naval fuel sales. Spent fuel storage sites are scattered, operating at or beyond capacity, and difficult to protect.(22) The older vessels are in danger of sinking; although their spent fuel has become less radioactive with age and therefore less dangerous to handle, this makes them even more attractive as potent sources of bomb-making material.(23)

The Production and Testing of Nuclear Weapons. The main source of radioactive exposure probably comes from the production, not the exploding, of nuclear weapons. Since the United States and the Soviet Union produced the great majority of the weapons, it is their operations that have caused the most trouble.

The American nukes were mainly created in Hanford, Washington and the Soviet nukes in Chelyabinsk, Russia. Both sites are now contaminated beyond restoration. For forty years Hanford produced the plutonium for American nuclear bombs. That production process is inefficient; for every small amount of plutonium produced, there was a huge amount of liquid and solid waste, and as a result about 8,000 of Hanford’s employees have had to work on the cleanup, with disappointing results. As one report noted,

“Solid waste can be everything from broken reactor equipment and tools to contaminated clothing that a worker wore during the plutonium production activities. The solid wastes were buried in the ground in pits or trenches. Some of the waste was placed in steel drums or wooden boxes before being buried while some of the other waste was placed in the ground without a container to hold it. Depending on when the waste was buried, records about what was buried and where it was buried can be either very good, or in some cases, very bad.

“Besides the millions of tons of solid waste, hundreds of billions of gallons of liquid waste was also generated during the plutonium production days. These liquid wastes were disposed of by pouring them onto the ground or into trenches or holding ponds. Unintentional spills of liquids also took place. Liquid wastes generated during the process of extracting plutonium from the uranium “fuel rods” were put into underground storage tanks. Just like with the solid wastes, while some records accurately describe the kinds of liquid wastes that were generated and where they went, some of the spills and the volume of the spills went undocumented.”

This narrative recounts only a tiny portion of the sad situation in Hanford. Then in 2018, the whole demolition process was halted because airborne radioactive particles were being found ten miles away.(24) There is little prospect that Hanford will ever be returned to a wholesome environment.

As for the Soviet nuclear weapons, the production, as well as a reprocessing plant, were located in a facility called Mayak, near Chelyabinsk, southern Siberia. For several years the radioactive liquid waste was simply “buried” in local water systems, but the effluent kept heating itself too much, so tanks were built to cool it. Then on 29 September 1957, one of the cooling tanks exploded—a catastrophe known as the Kyshtym Disaster. The plume irradiated some 270,000 people in Central Asia. Although the local people were not told what had happened, a week later about 10,000 of them were evacuated. The region was closed off and designated as a “nature reserve.” An area of 800 to 20,000 km² remains heavily contaminated. Lake Karachay, which received much of the liquid waste, remains “the most polluted spot on earth.” If you step into the water you will die, and if you spend more than a few minutes on the shore, your genetic code will be permanently damaged.(25) The river Techa is contaminated, and the dangerous water channels zone moves approximately 100 metres downstream per year toward the Arctic Ocean. It will eventually dump tons of radioactive waste into the Arctic ecosystem as a legacy of the Cold War.

But neither Americans nor Russians are the population most affected by nuclear testing. The Marshall Islanders have suffered even more. Between 1946 and 1958 the US conducted 67 nuclear tests in the Marshalls, and 72 years later the residents are still experiencing severe health problems. Moreover, one of Marshall islands, Runit, is the site of a giant concrete dome that was built to cover radioactive debris from the tests. However, rising sea levels mean that the toxic waste is now leaking into the ocean. Scientists worry that the dome may collapse completely and contaminate the whole Pacific.(26)

These baleful facts have been mentioned to remind us all that the most serious source of massive radiation will never be nuclear reactors, but nuclear weapons —both the old tests and the new modernization projects, which aim to produce a new generation of improved weapons. Any effort to reduce the risk of massive radiation exposure must be linked to a campaign to abolish nuclear weapons, which remain the primary source of radiation exposure.

The Waste from the Nuclear Power Industry

Now we turn to the management of waste from nuclear reactors that generate the electricity so essential in modern life. As of early 2019, the IAEA reports that there are 454 nuclear power reactors, 226 nuclear research reactors in operation around the world, and an additional 54 under construction(27). All of them produce radioactive waste. Moreover, waste is generated, not only during the burning of fissile materials in the reactor but at any point in the fuel cycle, including the stages of mining, transporting, and fabrication of the fuel rods. For example, large amounts of tailings are extracted when the mine tunnels are dug. This dirt and rock debris will contain some uranium ore and is usually dumped above ground in engineered dams, then covered with clay to prevent the release of radon gas. The piles of tailings may remain there indefinitely without further attention.

Another waste that can endanger public health is tritium, a radioactive isotope of hydrogen that is sometimes used to make signs glow in the dark. It is an undesirable by-product of nuclear reactors and in Canada is released into waterways, slightly poisoning the drinking water.(28) It is an essential component of all nuclear weapons. Tritium decays rather quickly, with a half-life of 12 years, and every warhead must be replenished regularly. Without it, the bombs become duds. There is an impending shortage in the US, which must either expand its capacity to produce the tritium for its nuclear arsenal or acquire it from foreign sources. But Canada will export radioactive material only for peaceful purposes(29) and Canadians joke that they will gladly go on drinking a little tritium if that’s what it takes to disarm America’s nuclear weapons.

The Fuel Rods. Finally let’s consider the main kind of waste that this plank— Number 18—is meant to address. High level waste is inevitably produced inside each reactor as its fission boils water, making steam to turn turbines and generate our electricity. The core of a reactor consists of bundles of fuel rods—usually uranium or plutonium. When a new bundle is inserted into the reactor, neutrons begin to bombard it and initiate a fission reaction. The fuel is kept in a coolant, usually water or sometimes heavy water, and the fission process is controlled by a substance that can absorb neutrons. By moving these control rods or out, the operator can determine how much fission will take place.

Every two years a third of the fuel is replaced and the other two-thirds are moved around to make for even burning. After six years, the whole assembly is removed — long before all possible fission has taken place.

This “spent fuel” is of course still millions of times more radioactive than when it was fresh,(30) and will remain dangerous for many thousands of years. It is transferred immediately to a large pool of water, where it will remain submerged and cooled for about five years. Then, with the energy having decayed a bit, it can be moved to dry shielded casks. Usually these are kept on-site in concrete bunkers, awaiting transfer to a permanent location. A space the size of a football field can contain about thirty years of sa reactor’s high-level waste.

The maintenance of these fuel rods at the reactor site is clearly a security problem, though the rods are too contaminated with other materials to be used as a nuclear bomb. They could, however, be used for “dirty bombs,” if the thieves could handle them without being killed themselves. A “dirty bomb” would be composed of a conventional explosive along with a package of radioactive waste, presumably to be exploded in some crowded spot. Many people might be killed locally and the area would be seriously contaminated, but the effects would be far more limited than from the explosion of a fission bomb. A “real” nuclear bomb must contain uranium or plutonium of a quality that requires reprocessing.

Reprocessing. And much nuclear waste is indeed reprocessed. The IAEA estimates that of the 370,000 metric tonnes of heavy metal produced so far by nuclear power reactors, 120,000 metric tonnes have been reprocessed.(31)

In this process, the fuel rods are chopped up and dissolved in nitric acid. The radioactive mixture is then processed chemically to remove the plutonium and uranium, which then can be mixed with depleted uranium oxide in a MOX fabrication plant to make fresh fuel. Unfortunately, that MOX fuel is more dangerous than uranium fuel, and it cannot be reprocessed. The remainder of the radioactive stew is still a high-level waste but its half-life may be reduced to about 9,000 years.(32) Reprocessing does not reduce total radioactivity but only dilutes it by distributing it among several components, thereby allowing it to be reclassified as low-level waste, which is still deadly.(33) Separating out the plutonium makes it available for those who want to build a genuine nuclear bomb, thus compounding the difficulty of preventing weapons proliferation. Reprocessing offers no solution to either our safety or our security problems.

Dumping Waste into the Oceans. Between 1946 and 1993, thirteen countries dumped nuclear waste in the ocean. There was a voluntary moratorium on dumping low level waste, but not until 1993 was dumping all radioactive waste at sea totally banned by international law.(34)

A Wall Street Journal article asserted that plutonium levels are 1,000 times normal on the seabed fifty miles from San Francisco. Some 50,000 containers of radioactive waste were dumped there a few decades ago.(35) The United States dumped more than 110,000 containers of nuclear material off its coasts until about 1970. Russia dumped 17,000 containers, 19 ships containing radioactive waste, 14 nuclear reactors, including five that still contain spent fuel, 735 pieces of contaminated heavy machinery, and its four lost submarines. European states dumped 28,500 containers into the English Channel, some of which now are leaking.(36)

This ocean disposal practice is not without its supporters. Some studies have sampled seawater and tested it for radioactivity without finding significant increases yet.(37) Others even see advantages in dumping at sea. The oceans are deep and surely would dilute the isotopes by dispersing them widely, which cannot be done on land. Terrorists or would-be bomb makers would have difficulty finding and retrieving the containers. On the other hand, the fish would surely suffer, and already humans are cautioned against eating large fish such as barracuda, or sturgeon, which consume smaller fish and thereby concentrate the toxins. Any renewed habit of dumping radioactive substances would, among other things, increase the reasons for avoiding seafood.(38)

On the other hand, the wastes could perhaps be buried in a subduction zone on the seabed. Geological processes would eventually carry the waste downward into the earth’s mantle.(39) This plan would require that the Law of the Sea be amended, but some researchers consider it potentially the best way of disposing of radioactive waste.

Burying the Waste Underground. No one wants the responsibility for protecting life on earth a million years in the future. Whatever method is chosen will have defects that cannot be foreseen now. Still, of all the procedures being considered in 2019, the “least bad” option is widely considered to be burial of the radioactive wastes underground. Many countries have proposed such schemes and much money has been spent in preparations, but nowhere has such a plan been fully implemented. Public opinion in the locality chosen is generally unfavorable. Probably the most progress has been made in Finland, where plans are far advanced to bury 3,000 sealed copper canisters, each up to 17 feet long and containing about two tons of spent reactor fuel. There are up to twenty miles of tunnels in the repository, where the canisters will be buried, sealed in clay, and left forever.(40)

There are also other proposals for burying the waste. One, called “Remix and Return,” suggests grinding high-level waste with the tailings from uranium mines and mills. The material should be brought down to the level of radioactivity that existed in the original ore and put back into the empty uranium mines from which it originated. There is a kind of poetic elegance to the notion, but it has practical shortcomings. The main problem is that the wastes that contain plutonium can never be put back to the level of the original ore, for plutonium and some of the other materials had never existed before humans created them, and will forever remain too toxic.(41)

Even if there were consensus that burying the waste is the best method, a question remains: how deep? Some people believe that the safest approach is to put the waste about five kilometers below the earth’s surface. There are already plenty of radioisotopes down there, and the ones we humans contribute to the mix will add comparatively little risk. If this is the most acceptable approach, we will have only one further matter to decide: Whose backyard shall we choose for the hole?

Nuclear Security Summits

In 2009 President Barack Obama addressed a crowd in Prague, calling attention to the dangers of nuclear terrorism and promising to move the United States toward nuclear disarmament. According to people on his team, he really wanted to greatly reduce nuclear weaponry—but he failed. Instead, in order to gain the necessary consent of Republicans in Congress to the New START Treaty, he agreed to “modernize” the US arsenal over a period of decades, at a cost of more than $1 trillion.

However, Obama’s concern about the risks of nuclear terrorism did have some modest result. During the following year he hosted an international conference to draw attention to the need to secure nuclear material. Forty-seven countries and three international organizations participated in the first of what came to be called the Nuclear Security Summits. There were four in all, which occurred two years apart and ending in 2016. The first and last sessions were held in Washington, D.C. with Obama as host. Russia declined to participate.

The summits were occasions for heads and state and government to discuss threats of nuclear security. Negotiators for the various countries (known as “Sherpas” and “Sous Sherpas”) conferred in between the meetings nd prepared commitments and declarations of intent to be presented in the next session. As a result, all the participating countries agreed to pursue optimum security for any highly enriched uranium or plutonium in their custody and, if at all possible, the reduction in the use of these materials. This involved more frequent reviews of state security by the International Atomic Energy Agency (IAEA).(42)

The fourth summit ended with the plans for an expanded membership in the Nuclear Security contact group, which would meet in various for a held, mainly in Vienna, the headquarters of IAEA.(43)It is not obvious whether these meetings have resulted in much improvement in the security of the vast and growing waste materials around the world, especially since Obama was succeeded by a president with even greater aspirations for the growth in nuclear weapons.

References for this article can be seen at the Footnotes 3 page on this website (link will open in a new page).