D. The Cycle of Nuclear Power Generation

The nuclear fuel cycle contains seven basic steps:

• Uranium mining and milling
• Conversion
• Enrichment
• Fuel fabrication
• Power generation
• Reprocessing
• Storage.

Most nuclear fuel is derived from the element uranium. Uranium deposits are found all over the world, but most mining occurs in Kazakhstan, Canada, Australia, Namibia, and Russia.¹

Mills grind the mined uranium ore into a concentrated form know as “yellowcake.” This substance is then converted into a gas that is enriched to raise the percentage of fissile uranium that can be used in reactions for power generation.

Source: http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/nuclear.html

Enriched gas is transformed into a powder, which is compressed into fuel pellets. These pellets are placed in fuel rods, which are then bundled into assemblies that serve as the energy source for nuclear power plants.

In the core of the reactor, the uranium fuel contained in hundreds of assemblies is split, releasing vast quantities of heat that are used to create steam and to power an electric generator. Spent fuel assemblies are removed and stored in on-site pools, where they continue to emit radiation as they cool from superheated temperatures.²

Reprocessing and Breeding
Spent fuel can either be stored immediately or reprocessed. Reprocessing employs certain advanced techniques to separate the fuel into its various chemical components and recombines these elements to create new fuel. The standard method for reprocessing is known as Plutonium and Uranium Recovery by Extraction (PUREX). Because this process results in the isolation of plutonium, the main ingredient in nuclear weapons, it can easily be used to produce fissile material for military purposes and is considered a serious proliferation risk.³

Other techniques have been developed that address concerns about proliferation. The most common one is known as MOX after the mixed oxide fuel it produces. The fuel and byproducts created using this method remain highly radioactive. In addition, more plutonium is removed from spent fuel when MOX is burned than is the case with other reprocessing techniques. For these reasons, MOX is considered a more proliferation resistant and thus politically acceptable method of reprocessing.

Several countries, notably the United Kingdom, Japan, and France, engage in reprocessing activities, and Japan has announced that it is engaged in building the first reprocessing facility designed solely for peaceful purposes.⁴ Official policy dating back to the Carter administration ensures that reprocessing does not occur in the United States because it could lead to the proliferation of plutonium and other materials used to make nuclear weapons.⁵

Weapons-grade plutonium can also be produced by special reactors known as breeder reactors. As the name indicates, these reactors are capable of ‘breeding’ more fissile material than they consume. Breeder reactors have, at various times, been in operation in the United States, France, the United Kingdom, Russia, and Japan, but are now rare in developed countries.⁶

Of late, India has been one of the only countries openly developing a network of breeder reactors to the dismay of many in the international community. India’s tense relationship with Pakistan and refusal to join the Nuclear Nonproliferation Treaty, described in the section on “Nuclear Nonproliferation” below, make the prospect of proliferation in South Asia a troubling one. As was the case with reprocessing technologies, the United States has placed a moratorium on the commercial development of breeder reactors, citing nonproliferation grounds.

Waste Storage

The final stage in the nuclear fuel cycle for fuel that is not reprocessed in some fashion is the storage of nuclear waste. As mentioned above, most waste is temporarily stored on-site to be cooled, but long-term storage is a serious problem for many nations.

In 1982, the United States Congress enacted the first Nuclear Waste Policy Act, which expressed a commitment by the federal government to assume joint responsibility with private operators in addressing the problem of waste disposal. Congress commissioned a series of studies to evaluate the potential of selected sites to serve as a permanent repository for radioactive waste from American power plants.⁷

Eventually a single site at Yucca Mountain, Nevada was settled on as the prime candidate for continued Department of Energy analysis. Development of the site was enabled by the creation of a Nuclear Waste Fund, Nevada was settled on as the prime candidate for continued Department of Energy analysis. Development of the site was enabled by the creation of a in 1982. Contributions to the Fund are drawn from proceeds from a 0.001 cent tax per kilowatt/hour paid by consumers of electricity generated from nuclear power.⁸

After 20 years and billions of dollars of investment, however, Yucca Mountain is still not ready to open and has emerged as an important lesson in the difficulty of not only predicting the suitability of sites for long-term storage but also securing public support for keeping nuclear waste in the neighborhood.

There are four issues involved in the controversy over Yucca Mountain. The first is the “not-in-my-backyard” argument and the problem of public opinion. Despite many years of research that went into finalizing the location of the repository site, residents of Nevada remain unconvinced they alone should provide a home for the nuclear waste produced by the entire country.

Nevadans feel especially aggrieved because there are no nuclear power plants in the state. It is not surprising that, even though everyone acknowledges that the waste must be put somewhere, no one wants to volunteer his or her own backyard. Consequently, the state of Nevada has taken the federal government to court to challenge the designation of Yucca Mountain.⁹

Second, there is the issue of Yucca Mountain’s capacity. It is estimated that existing collections of waste, which are housed at 72 reactor sites across the country, would entirely fill up Yucca’s projected capacity.¹⁰ At present levels of nuclear power generation, some believe that nine additional sites equivalent to Yucca Mountain would be necessary to store the waste that will accumulate over the next century.¹¹ Based on this information, many argue that the development of reprocessing technologies will be not only wise but also necessary if nuclear energy is to continue to be a sustainable source of power.

Third is the issue of transporting waste materials from the sites where they are currently stored. Bringing existing waste to Yucca Mountain will require shipments passing through 43 of the 50 states. Many worry about the possible health risks that even low levels of exposure might pose to the large segments of the country’s population that live along slated transportation routes. A recent National Academy of Sciences study has dismissed this fear, with the finding that the risks of accidental radiation leakages during transportation are minimal.¹² Nevertheless, substantial reservations among policymakers remain.

Finally, there are concerns about the long-term safety of the site. The initial Environmental Protection Agency (EPA) standards created in June 2001 mandated that limits on radiation emissions would remain in effect for a 10,000 year period. These standards were challenged in court by a number of environmental groups and by the state of Nevada, and a federal court ruled that they were inconsistent with recommendations issued by leading scientific authorities.

The Yucca Mountain nuclear waste site was dropped in early 2010 due to budget cuts that eliminated federal funding for the project.   It was decided that the site would be shut down despite future plans for the formation of new nuclear plants.In response, the EPA revised its guidelines to apply for a period up to 1 million years, far longer than the U.S. government has ever attempted to regulate anything in the past. Scientists find it very difficult accurately to predict that far into the future, so the new standards have proven contentious. The controversy delayed any action on the site and has pushed back its opening date to 2017 or beyond, many years later than was originally intended.

Consequently, the federal government was sued by several nuclear utilities for violating the obligations spelled out in the Nuclear Waste Policy Act.¹³ The Yucca Mountain nuclear waste site was dropped in early 2010 due to budget cuts that eliminated federal funding for the project.¹⁴  It was decided that the site would be shut down despite future plans for the formation of new nuclear plants. 

Picture Source: http://en.wikipedia.org/wiki/Image:Yucca_Mountain_2.jpg

1 “World Uranian Mining”
2 Weeks 223
3 Weeks 232
4 Parfit 26
5 Weeks 230
6 “Breeder Reactor”
7 Holt, “Civilian Nuclear Waste Disposal,” 7; “Our Governing Legislation”
8 Weeks; “Nuclear Waste Fund Fee Adequacy: An Assessment” 1-2
9 Holt, “Civilian Nuclear Waste Disposal,” 8
10 Holt, “Civilian Nuclear Waste Disposal,” 6
11 “Reactor Dreams;” Holt, “Civilian Nuclear Waste Disposal,” 2
12 Weeks 224
13 “EPA Yucca Mountani Fact Sheet #2;” Baltimore; Weeks 222; Holt, “Civilian Nuclear Waste Disposal,” 2-3
14 Whittel