Radioactive Waste

I wonder that some think that there is difficulty in disposal of radioactive waste. Toxic waste is even more difficult. Radioactivity levels reduce by time but toxicity not. There is no difficulty in disposal of radioactive wastes except the unjustified concerns of the public that oppose radioactive waste disposal in their vicinity. Currently; there are well established methods; subject to strict local and international regulations; and approaches to deal with radioactive waste based on the waste form (solid, liquid. gaseous) and the radioactivity level (low, intermediate, high). Primarily; three methods are applied:

1. delay and decay: to maintain waste in tanks for some periods of time to allow decay of radioactivity and then to be disposed of to environment.
2. dilute and disperse: to dispose to environment (through dilution and dispersion) as ocean, sea, atmosphere, etc.
3. contain and concentrate: This is used mainly for high level radioactive waste as spent fuel or the spent fuel reprocessing products; either in wet storage, dry storage, or incineration&containment in barrels, or vitrified waste.

First, let's define what is meant by "nuclear waste", as it is important to categorize what exactly is waste, in the same way that people's "garbage" is now broken down into categories like "recyclables", "compost", "yard waste", etc.

In general, there are three categories of nuclear waste, rated by their radioactivity: "low-level", "medium-level", and "high-level" waste.

Low-level waste consists of normal materials used in the production or handling of nuclear products, and which does not itself emit any radiation. The primary concern here is toxic issues, as many nuclear products are toxic as well as radioactive. Remember that "nuclear" products are not just reactor fuel - we use radioactive materials in a vast variety of things, from medical devices such as X-Ray, CAT, and MRI machines, to alloys of specialty metals (used in a myriad of places), to even things like batteries. Low-level waste (which composes 99% of all "nuclear waste") is a huge variety of items: normal clothing, latex gloves, metal handling tools, tubs where materials were mixed, etc.

As such, the problem with disposing low-level waste is functionally identical to that of disposing standard "toxic" waste. The items in question aren't really radioactive in any meaningful way, but they still are contaminated with material that can cause significant environmental harm. So, they should be disposed of in the same way we'd like to dispose of things such as toxic chemicals (DDT, Ditoxin, Petroleum byproducts, etc.). Currently, there's only really two ways to get rid of these items: bury them in sealed containers away from people (which, frankly, is not a real good solution, since the time it takes for such toxic material to decompose/break down is quite a while), or burn them in special incinerators.

With low-level waste, there is very little risk associated with transporting the waste to a disposal point. Overall, low-level waste is less difficult to dispose of properly than most toxic industrial chemicals, but more difficult than "ordinary" toxic waste such as household cleaners, etc.

Medium-level nuclear waste is generally metals and other compounds which have been exposed to extended amounts of radiation, and thus have become radioactive themselves. Typical of items in this category are equipment used in a nuclear reactor (as they become radioactive after exposure to the nuclear fuel or coolant), or items used to house, transport, or create the nuclear fuel.

These items do pose a radiological threat, though only over a long period of time. As mildly radioactive materials, people exposed to them over months or years would receive radiation that would significantly increase their chances of developing cancers or other radiologically-induced diseases. However, short-term limited exposure is not particularly threatening.

Medium-level waste is generally not notably toxic - the primary threat is long-term exposure to the material. As such, the disposal problem is to isolate the waste until the level of radiation given off drops to a safe level. As most medium-level waste radiates low-intensity radiation, but does it for an extended time (decades at a minimum, often centuries), disposal methods need to consider long-term isolation storage, though radiation shielding does not have to extensive. As most medium-level waste is building materials or equipment, liquid leakage is generally not a problem. Common solutions are to store such items in a sealed mine. Old salt mines are popular, as they have very little water leakage, and the mild radiation is easily absorbed by the thick salt walls.

High-level waste is what most people think of when "nuclear waste" is spoken of. Reactor fuel makes up most of this category, but also a variety of spent isotopes from X-Ray and MRI and other medical uses is also of a concern. In general, this category is made up of materials that are naturally radioactive, whether being an "ordinary" radioactive element, or a byproduct of nuclear decay that are still radioactive.

Unfortunately, most high-level waste is not only extremely radioactive (giving significant amounts of short-term radiation if touched, ingested, or inhaled), but also quite toxic. Indeed, for many high-level waste products, the long-term toxic hazard outweighs their relatively short-lived radiological hazard. Most high-level wastes are easily absorbed into the ecosystem, able to infiltrate the food chain quickly, and can cause catastrophic damage to all parts of the environment.

As literally the most dangerous materials of the modern world (with the possible exception of customized biological weapon materials), they pose a myriad of problems. Their radiological effects require that they be isolated and contained in heavily-shielded places, while their toxic nature requires such places to be resistant to the corrosive effects of the waste and also to be sealed from contact to the local environment. The radiation characteristics of each material differ wildly, so a solution for one waste material may not be suitable for use by other waste materials. Similarly, the chemical and toxic characteristics of each waste material make designing a one-size-fits-all solution practically impossible. For instance, plutonium has a moderate level of radioactivity, very long half-life, very high toxicity, but is rather chemically inert. Cesium and Strontium, however, have high levels of radioactive emissions, a short half-life, low toxicity, but are highly chemically active (i.e. they easily combine with other molecules and thus are easily absorbed into the ecosystem).

Due to these serious problems of toxicity, chemically active nature, and high radiological risk, transportation of these items is difficult to do safely. Disposal consists of extreme isolation and containment in highly-corrosion-resistant containers.

Fortunately, high-level waste is a very small amount. It can be further reduced by efficient recycling and re-processing "spent" reactor fuel, allowing for up to 90% of the "spent" fuel to be re-used, and thus kept out of the waste disposal chain. Estimates for the worldwide annual volume of high-level waste depend on the amount of recycling that happen, but it is relatively small - in the dozens of tons. Thus, while the problem is extremely difficult, fortunately the amount of such materials is tiny.

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To answer the question, each form of waste has different levels of problems associated with it. Broadly, here are the categories of problems:

• Toxic - the material is poisonous or unhealthy if ingested, inhaled, or touched.
• Corrosive - the material causes significant damage to other materials which come in contact with it.
• Radioactive - the material emits radiation which may cause harm to living tissue
• Explosive/Heat Risk - the material may explode under certain circumstances, or is significantly exothermic (i.e. produces heat on its own)
• Chemically Reactive - the material is prone to producing volatile, toxic, or other dangerous compounds when exposed to the normal environment.
• Militarily Valuable - the material has military value; that is, it is an important ingredient in creating some sort of weapon

Each level of nuclear waste (and, even within each level) has a different combination of the above characteristics.

Toxic materials must be either rendered chemically non-toxic, or isolated from exposure to the environment. Transportation of these materials is generally dangerous, as accidents are hard to clean up and the effects of a spill can be widespread.

Corrosive materials must be rendered chemically inert, or stored in special containers resistant to the corrosive effects. Transportation is very dangerous, as they pose a severe hazard to the area around the accident (though less danger to large areas).

Radioactive materials must be stored in shielded containers until the amount of radiation emitted by the material is at a safe level. Transportation is generally safe, as accidents are relatively easy to contain (though expensive).

Explosive and Exothermic materials must either being chemically neutralized, or sealed in a non-reactive container and isolated from any outside contact. Transportation is an extreme hazard, as any accident can result in almost total destruction of the area around the spill (though, no larger-scale damage).

Chemically Reactive materials must be either be chemically destroyed (i.e. turned into a compound which isn't reactive), or stored in special chemically inert, sealed containers. As with explosive/exothermic materials, transportation is extremely hazardous, as any accident can cause widespread destruction.

Militarily Valuable materials must either be guarded from theft, or reformulated into materials that are impractical for making into a weapon. Transportation is expensive due to required police/military protection of the material, but is not otherwise difficult.

It should be noted that while most of the above solutions mention chemically changing the material into a non-problem compound as an option for disposal, in reality, the expense of doing so is usually prohibitive. In many cases, it is not practical to sort the materials enough to allow for custom chemical treatment. In other cases, the cost of the process to do the conversion is extremely high or has severe environmental side-effects. Mostly, however, we simply don't know how to chemically adjust the waste into something safe.

Note that many (most) of the problems associated with the disposal of nuclear waste also apply to the disposal of any of the myriad of industrial chemicals in common use in any industrialized society. Indeed, the actual danger posed by the use of industrial chemicals is considerably larger than that of nuclear waste, due to two factors: (1) industrial chemicals are used/transported/disposed of on a vastly grander scale than any nuclear material (several million times the amount of chemicals are used vs nuclear materials) and (2) industrial chemicals are handled (and disposed of) with far less care than nuclear materials. In addition, in a pound-for-pound comparison, nuclear materials are not much more damaging to the environment than many industrial chemicals, and generally no more difficult to clean up (which is to say that both industrial chemicals and nuclear materials are difficult, expensive, and time-consuming to clean up, but neither is significantly more than the other).

The waste from coal power stations has virtually no radioactive waste where as a

nuclear plants waste is nearly all toxic.

Completely Wrong. All coal waste is toxic. Coal fired power plants chuck out all the radioactive elements that were in the coal that was burned. This is fairly old news from the 70's. Excellent source: http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html .

More facts that are totally ignored by the media as governors and industrial groups lobby to continue to launch toxic, hazardous and poisonous elements and compounds into the air from the stacks, and onto the land downwind.

The following is quoted. There is no copyright on this article at this website. Thanks to ORNL.

Web site provided by Oak Ridge National Laboratory's Communications and External Relations

ORNL is a multi-program research and development facility managed by UT-Battelle for the US Department of Energy

"Because existing coal-fired power plants vary in size and electrical output, to calculate the annual coal consumption of these facilities, assume that the typical plant has an electrical output of 1000 megawatts. Existing coal-fired plants of this capacity annually burn about 4 million tons of coal each year. Further, considering that in 1982 about 616 million short tons (2000 pounds per ton) of coal was burned in the United States (from 833 million short tons mined, or 74%), the number of typical coal-fired plants necessary to consume this quantity of coal is 154.

Using these data, the releases of radioactive materials per typical plant can be calculated for any year. For the year 1982, assuming coal contains uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively, each typical plant released 5.2 tons of uranium (containing 74 pounds of uranium-235) and 12.8 tons of thorium that year. Total U.S. releases in 1982 (from 154 typical plants) amounted to 801 tons of uranium (containing 11,371 pounds of uranium-235) and 1971 tons of thorium. These figures account for only 74% of releases from combustion of coal from all sources.

Releases in 1982 from worldwide combustion of 2800 million tons of coal totaled 3640 tons of uranium (containing 51,700 pounds of uranium-235) and 8960 tons of thorium.

Based on the predicted combustion of 2516 million tons of coal in the United States and 12,580 million tons worldwide during the year 2040, cumulative releases for the 100 years of coal combustion following 1937 are predicted to be:

U.S. release (from combustion of 111,716 million tons):

Uranium: 145,230 tons (containing 1031 tons of uranium-235)

Thorium: 357,491 tons

Worldwide release (from combustion of 637,409 million tons):

Uranium: 828,632 tons (containing 5883 tons of uranium-235)

Thorium: 2,039,709 tons

Radioactivity from Coal Combustion

The main sources of radiation released from coal combustion include not only uranium and thorium but also daughter products produced by the decay of these isotopes, such as radium, radon, polonium, bismuth, and lead. Although not a decay product, naturally occurring radioactive potassium-40 is also a significant contributor.

According to the National Council on Radiation Protection and Measurements (NCRP), the average radioactivity per short ton of coal is 17,100 millicuries/4,000,000 tons, or 0.00427 millicuries/ton. This figure can be used to calculate the average expected radioactivity release from coal combustion. For 1982 the total release of radioactivity from 154 typical coal plants in the United States was, therefore, 2,630,230 millicuries.

Thus, by combining U.S. coal combustion from 1937 (440 million tons) through 1987 (661 million tons) with an estimated total in the year 2040 (2516 million tons), the total expected U.S. radioactivity release to the environment by 2040 can be determined. That total comes from the expected combustion of 111,716 million tons of coal with the release of 477,027,320 millicuries in the United States. Global releases of radioactivity from the predicted combustion of 637,409 million tons of coal would be 2,721,736,430 millicuries.

For comparison, according to NCRP Reports No. 92 and No. 95, population exposure from operation of 1000-MWe nuclear and coal-fired power plants amounts to 490 person-rem/year for coal plants and 4.8 person-rem/year for nuclear plants. Thus, the population effective dose equivalent from coal plants is 100 times that from nuclear plants. For the complete nuclear fuel cycle, from mining to reactor operation to waste disposal, the radiation dose is cited as 136 person-rem/year; the equivalent dose for coal use, from mining to power plant operation to waste disposal, is not listed in this report and is probably unknown.

...

Although trace quantities of radioactive heavy metals are not nearly as likely to produce adverse health effects as the vast array of chemical by-products from coal combustion, the accumulated quantities of these isotopes over 150 or 250 years could pose a significant future ecological burden and potentially produce adverse health effects, especially if they are locally accumulated. Because coal is predicted to be the primary energy source for electric power production in the foreseeable future, the potential impact of long-term accumulation of by-products in the biosphere should be considered. "

Personally, more concerned about the complete waste slate, but the radioactive portion always deserves mention.

Simple search by high school chemistry students found the West Virginia coal trace elements shown in an average ppm for nearly 800 samples.

Antimony (Sb)

1.02

Arsenic (As)

17.13

Barium (Ba)

109.86

Beryllium (Be)

2.57

Bismuth (Bi)

0.32

Boron (B)

20.01

Bromine (Br)

23.88

Cadmium (Cd)

0.096

Cerium (Ce)

16.88

Cesium (Cs)

1.15

Chlorine (Cl)

959

Chromium (Cr)

17.85

Cobalt (Co)

7.41

Copper (Cu)

20.4

Dysprosium (Dy)

2.03

Erbium (Er)

1.09

Europium (Eu)

0.33

Fluorine (F)

62.68

Gadolinium (Gd)

1.46

Gallium (Ga)

6.45

Germanium (Ge)

3.09

Gold (Au)

6.062

Hafnium (Hf)

0.72

Holmium (Ho)

0.52

Indium (In)

0.91

Iridium (Ir)

0.95

Lanthanum (La)

9.23

Lead (Pb)

8.19

Lithium (Li)

19.09

Lutetium (Lu)

0.133

Manganese (Mn)

21.29

Mercury (Hg)

0.19

Molybdenum (Mo)

2.37

Neodymium (Nd)

8.65

Nickel (Ni)

13.99

Niobium (Nb)

3.21

Praseodymium (Pr)

3.11

Rhenium (Re)

0.57

Rubidium (Rb)

23.62

Samarium (Sm)

1.52

Scandium (Sc)

3.71

Selenium (Se)

4.2

Silver (Ag)

0.058

Strontium (Sr)

91.68

Tantalum (Ta)

0.195

Tellurium (Te)

0.083

Terbium (Tb)

0.261

Thallium (Tl)

1.194

Thorium (Th)

3.02

Thulium (Tm)

0.283

Tin (Sn)

2.2

Tungsten (W)

0.79

Uranium (U)

1.59

Vanadium (V)

24.36

Ytterbium (Yb)

0.8

Yttrium (Y)

7.53

Zinc (Zn)

14.97

Zirconium (Zr)

24.32

To determine emissions of these elements just follow the example above with the Thorium and Uranium and factor from those tons.