Low Level Waste

Disposal of LLW at commercial sites accounted for about 32% of the LLW disposed during 1994. Commercially disposed LLW is generally divided into five categories:

• academic (university hospitals and university medical and nonmedical research facilities)
• government (state and non-DOE federal agencies)
• industrial (R&D companies, manufacturers, nondestructive-testing operations, mining works, fuel fabrication facilities, and radiopharmaceutical manufacturers)
• medical (hospitals and clinics, research facilities, and private medical offices)
• utility (commercial nuclear reactors)

The Department of Energy has issued a quality report - IDB 1995 report - that summarizes data on high and low level wastes.

Low level wastes would include discarded construction wastes, resins, clothing, tools, and equipment that generally have low radioactivity levels. Such waste could be generated during operation or decommisioning of a facility. The following figures and tables from the referenced DOE report provide insight into the nature of the low level waste storage issue.

1. Figure - Volume and radioactivity of LLW disposed at commercial and DOE facilities during 1994.
2. Figure - Total volume of LLW disposed through 1994. Comparison of amounts stored at commercial and DOE facilities.
3. Table - Characteristics for Disposed LLW as of December 31, 1994
4. Table - Historical and Projected Volume, Radioactivity, and Thermal Power of Commercial LLW Shipped for Disposal
5. Table - Distribution of Total Volume and Radioactivity, by State, of LLW Shipped to Commercial Disposal Sites
6. Table - Breakdown of 1994 Low-Level Radioactive Waste by Type, Volume, and Radioactivity Received by Commercial Disposal Sites
7. Table - Average Concentrations for Representative Radionuclides in LLW at Commercial Disposal Sites
8. Table - Schedule of Actual and Projected Final Shutdown Dates for Commercial Light-water Reactors

To put low level waste in perspective-if all of the waste from the commercial sites were combined, it would occupy an area ~2300 ft x 2300 ft x 10 foot high. On the basis that a typical city block is 100,000 ft².This corresponds to an area the size of 53 city blocks. For comparison, the State of Minnesota Pollution Control Agency currently has licensed 27 open sanitary landfills and 24 demolition landfills having a total capacity of ~1160 city blocks. The size of the landfill for accommodating all low level radioactive waste to date throughout the country would be about 1.5 times the average small city sanitary landfill size. It is important to note that this area would cover all commercial waste from the 5 sources listed above.

Utilities are the major generators of low level waste. The cost of storing low level waste has become very expensive. As a result, most utilities have initiated programs to limit waste generation. In addition, a lot of waste may be stored on-site at the plants.

Currently waste can be shipped only to Barnwell, South Carolina and Richland, Washington. In 1982, Congress passed a law that required that all states join regional compacts for the purpose of siting low level radiactive waste storage landfills. For more information on status, news, compacts, issues. you may wish to visit the ACURI site. The ACURI site addresses frequently asked questions and provides details on the use of radioactive materials in education, medicine, research, as well as government and power generation.

High Level Waste

After 3 to 5 years in the reactor, one-third of the fuel assemblies are removed and stored in storage pools for typically about 10 to 20 years. During this period, the fuel loses much of its radioactivity and heat. After that period, the fuel can be stored in large sealed metal casks that can be cooled by air. The spent fuel assemblies are legally referred to as Spent Nuclear Fuel. If the fuel assemblies are reprocessed, the resulting waste is called High Level Waste.

Currently most spent fuel is being stored (over 29,000 metric tons) at the reactor sites. Very little (~750 tons) is being stored at 3 other storage facilities (West Valley, Morris Fuel Reprocessing Plant, Idaho National Engineering Laboratory). In 1977, the reprocessing option was disallowed by President Carter because of concern about nuclear proliferation.

1. Graphics/photos showing typical PWR fuel assemblies (BWR assemblies are smaller and weigh less)
2. Spent fuel storage facilities - pools, casks - various methods used
3. Behavior of radioactivity and thermal power produced as a function of time for fuel discharged from a reactor.

Typically a 1000 MWe reactor will discharge about 2 metric tons of high level waste each refueling. A 1000 MWe reactor has about 100 metric tons of uranium dioxide fuel, of which 3 to 5 tons consist of the fissile U-235. A PWR will discharge 40 to 70 fuel assemblies; a BWR will discharge 120 to 200 fuel assemblies.

1. Locations where spent fuel is currently being stored in the United States.
2. Annual amounts of spent fuel expected to be discharged from 1995 through 2030
3. Table giving specifics of typical characteristics of BWR and PWR Fuel Assemblies
4. Cumulative amount of spent fuel discharged through 1995.
5. Terminology used - acronyms, abbreviations
6. Glossary of Terms

The United States' Department of Energy (DOE) has prepared  very informative on line annual Integrated Database Reports  - CY 1995, CY 1996 - that provide detailed information, including tables and figures showing the history and projections of spent nuclear waste generation. The DOE report deals with both government (including military) and commercially generated spent nuclear fuel and waste. Reports for other years have been archived and are not accessible from DOE except possibly by request.

To put the volume of the high level waste into perspective-if all the current waste were stored as a single mass, it would occupy a space 140 feet x 140 feet x 10 foot high. Realistically, the actual space will be larger because the high level waste will be converted into a less dense vitrified (or glass form).

There is another way of looking at the spent fuel waste - How much area would ALL of the fuel assemblies for the 110 nuclear power plants of 500 to 1100 MWe occupy if they were placed side by side? Based on DOE projections, there would ~232,000 fuel assemblies discharged through 2030. These would occupy an area of ~100,000 ft², the area corresponding to about 1 city block -a very small area. Of course, the actual area would be larger because the spent fuel would be shielded and separated into smaller storage containers.

How much area would be needed for coal ash storage? We can look at this 2 ways -

• 3 small 20 MWe coal units operating for just 10 years would require a landfill equivalent to 20 city blocks. A rule of thumb is that 10% of the fuel results as ash.
• According to IAEA, a 1000 MWe plant generates 300,000 metric tons of ash per year. The density of ash is 55 lb per cubic foot. Based on this, the landfill required to handle each year's ash output would have to be 14 foot high and area of 857,000 ft² (equivalent to 8.5 city blocks )
• By comparison, a 22 square foot area would be needed for the fuel assemblies required to run a 1000 MWe reactor for a year.

For more on the current status and archived documents related to this formerly proposed long term storage location, please view a DOE site search for Yucca Mountain.

Please visit the Current Hot Topics page for information on proposed private fuel storage and transportation of nuclear waste.

 Reprocessing of Nuclear Fuel - 1960's through 2018

Reprocessing involves mechanical and chemical processes in order to extract the unused uranium and plutonium from the spent fuel. Wikipedia provides a good explanation of the available reprocessing methods:

• PUREX
• UREX
• TRUEX
• DIAMEX
• SANEX
• PYRO-A
• PYRO-B

Historical Perspective

In the 1960's when nuclear power was appearing on the horizon as a potential power source, reprocessing was viewed as a way of recovering unused fuel. At the same time, breeder reactor technology was being developed. The breeder reactors (fast fission) which would use uranium-238 would be used to produce plutonium-239, which could then be recovered then used in mixed oxide fuel to fuel thermal fission reactors.

Spent fuel from government plutonium production reactors at Savannah River and Hanford has been reprocessed onsite. Fuel from US Navy surface ship and submarine reactors has been reprocessed at the Idaho Chemical Processing Plant near Idaho Falls, Idaho. The unfortunate result of the reprocessing has been the generation of enormous volumes of highly radioactive liquids. Hanford tank leaks resulted in releases to the local environment. Plutonium has been found at the mouth of the Columbia River near Astoria, Oregon. Although both ICPP and Hanford reprocessing stopped in the 1990 timeframe, almost 90 million gallons of high level waste still remain in storage tanks on government reservations (See Table 3 of An International Spent Nuclear Fuel Storage Facility -- Exploring a Russian Site as a Prototype: Proceedings of an International Workshop).

The early commercial reactors built in the 70's were initially designed to hold spent fuel in the onsite storage pool  for 1-1.5 years, then have the fuel sent to a reprocessing facility (e.g.West Valley, NY) . That facility commercially reprocessed spent fuel until concern about nuclear proliferation brought on by the Indian explosion of a plutonium fission device resulted in presidential executive orders by Ford and Carter to defer reprocessing. West Valley was then shutdown. Although Reagan rescinded the order during his presidency, the process in the US has been considered uneconomical. Two planned reprocessing facilities at Barnwell, SC and Morris, IL never became operational.

Meanwhile, France's COGEMA, Britain's British Nuclear Fuels (BNFL), and the Russian and Indian governments started up and continued to operate spent fuel reprocessing facilities during the US abstention. The Sellafield facility in the United Kingdom has had storage tank and leak issues as have US facilities. Less information has been available about the facilities in France, Russia, and India.

In the United States, periodically there is renewed political interest in reprocessing, likely spurred by the ongoing political debate about Yucca Mountain as the national spent fuel repository. Reprocessing has disadvantages and advantages.

The Future

If reprocessing is to be successful in the future, the following must happen:

1. Processes must be developed and used that do not produce large amounts of highly radioactive liquid waste.
2. The chemical processes must be thoroughly understood so that dangerous conditions do not develop which could produce leaks to the environment (e.g. explosions due to unexpected chemical reactions).
3. The complete cycle should be developed and characterized ahead of time. Engineering on the fly is unacceptable and costly.
4. There needs to be community, political, and scientific agreement beforehand so that history does not repeat itself. Local communities are still paying for the secrecy, short-sightedness, and disregard of the impact on the environment and public by the management of government weapons production facilities, e.g. Hanford and Savannah River, from World War II and the Cold War.