Transportation and Storage of Nuclear Waste
by
Daniel Grykien
5/9/01

Nuclear power has facilitated a seemingly endless supply of energy for both the U.S and much of the world. In addition to civilian use, nuclear energy also has many applications within the military, such as the manufacturing of nuclear weapons. However, these extraordinary advancements in exploiting the atom come with life threatening consequences. The wastes generated from nuclear power are growing exponentially. Nuclear waste transportation and storage has become a serious environmental issue within the US, as well as on a global scale. This page will be dedicated to identifying the truth behind the concerns, dangers, and future of the world's nuclear waste .

Abstract


The US is creating a surplus of harmful nuclear waste everyday. Although there is both legislation and governmental agencies which regulate the deadly by-products of nuclear generation, every American is still at risk.

Since the amendment to the Nuclear Policy Act of 1987, Yucca Mountain, Nevada, has been the only area studied for the long term geologic storage of nuclear waste. Currently, all generated high-level nuclear waste (HLW) is temporarily stored, awaiting the construction of a permanent geologic storage facility. However, there is much political and public opposition surrounding the Yucca Mountain site. Among the major concerns are volcanism, hydrology, radioisotope transportation and seismic stability. As it appears, both Congress and the Department of Energy are wasting millions of dollars pushing for an unsuitable geologic repository.


Introduction


There are numerous activities, which can be linked to the generation, storage and transportation of nuclear waste. Any practice dealing with raw radioactive materials will most certainly generate nuclear wastes. All parts of the nuclear fuel cycle, from uranium mining and preparation for use, through the use these fuels to generate electricity produce some radioactive wastes (
Uranium Institute, 2001). Responsibilities for the management (storage and transportation) of nuclear wastes are defined by the laws set forth by Congress. These laws are administered by governmental agencies that comply with the details in the Code of Federal Regulations, guidance documents, and internal orders (Lowenthal,1997). "Responsibilities for the action, monitoring and enforcement, and standard setting are divided among several agencies: the Department of Energy (DOE), Environmental Protection Agency (EPA), National Academy of Sciences –National Research Council (NRC) and the Department of Transportation (DOT) are all involved in different aspects of radioactive waste management for DOE projects on the federal level" (Lowenthal,1997).

top

Uranium and Fission

Uranium, a very dense, naturally occurring metal was discovered in 1789. It was apparently formed in a super nova approximately 6.6 billion years ago. Originally discovered in the mineral pitchblende, it was named after Uranus which was discovered eight years earlier (
UIC,1999). Uranium occurs in most rocks in concentrations of two to four parts per million, and is a common element in the earth's crust. However, uranium is distributed unevenly throughout the world (Table 1 illustrates worldwide distribution of uranium). About 80% is located in six countries with nine companies accounting for 82% of uranium production (UIC,1999).

Table 1. World wide totals of uranium distribution (UIC,1999)

Country

Tonnes U3O8

% of World

Australia

894,000

25%

Kazakhstan

681,000

19%

Canada

507,000

14%

South Africa

335,000

9%

Nambia

291,000

8%

Brazil

281,000

8%

Russian Fed.

195,000

5%

USA

130,000

4%

World Total

3,638,000

 


Uranium like other elements occurs in isotopes (nuclides with the same number of protons, but different numbers of neutrons). Of the sixteen isotopes of uranium, 235 U and 238U are the two most frequently occurring. The mixture of these two isotopes constitutes the 'natural' uranium as found in the earth's crust (UIC, 1999). 238U is the most common form of element, representing 99.27% of all the earth's uranium. The remaining percentage of nature's uranium is 235 U (0.72%) and 234U(0.0055%) (UIC, 1999). Uranium ore is extracted from open pits, close to each mine is a mill, which crushes rock and separates the uranium. The leftover material, including 85% of the total radioactivity, litters the ground in the form of uranium "tailings" which are simply stockpiled, often above ground, where they continue to emit dangerous radon gas. Canada alone has 200 million pounds of tailings (UIC, 1999). A report delivered to the British Colombia Royal Commission of Inquiry declared that the failure to properly handle uranium tailings has led to internal lung doses calculated to be 100 rems per year to the local public (UIC, 1999). Calculations show that the public in areas near uranium tailings will receive 25 percent higher radon daughter radiation over the course of their lifetimes than populations living at a safe distance from the tailings (UIC,1999).
The extracted ore, called yellowcake, is processed and undergoes chemical transformations converting it to useful fuels (uranium dioxide and uranium hexafluoride) for nuclear reactors (UIC, 1999). The quantity of nuclear reserves is as finite and limited as that of fossil fuels. Uranium Institute figures estimate the total world recoverable resources of uranium at 3, 256,000 tons. Existing power plants operational worldwide require 75,000 tons of uranium a year to produce roughly 17% of the total world power requirements. The total resources will be sufficient to meet current and anticipated demand for only 42 years (UIC,1999).

The isotope 235U is very important. It has 92 protons and 143 neutrons, which lends it its atomic mass of 235.235U will undergo thermal and fast fission under certain conditions which means that when a nucleus of a 235U is split by a neutron, some energy is released as heat and two or three additional neutrons are thrown off (UIC, 1999).(Figure 1.) However, some times the 235U neutron will bounce off of the nucleus or become absorbed by the creating another isotope, 236U. If fission does occur the expelled neutrons split the nuclei of other 235U atoms releasing further neutrons, producing a chain reaction. This reaction takes place over and over again millions of times producing a very large amount of heat from a very small amount of uranium. It is this process, in effect the "burning of uranium", which occurs inside a nuclear reactor.

238U however, will undergo fission only when struck by faster neutrons of certain energies. When it does undergo fission, 238U will go through a series of decays, forming Plutonium 239Pu. In typical reactors, 239 Pu will go on to fission with thermal neutrons creating nearly 30% of the power generated by the reactor (UIC, 1999). The probability that fission may occur is described by the cross-section for that reaction.

Figure 1.Graphic example of the uranium-235fission process (StarNine,1996).
top

History of Nuclear Legislation

The United States was the first nation to produce a self-sustaining nuclear reactor ( in Hannaford,Washington). It was also the first nation to detonate a nuclear weapon (
Lowenthal,1997). These technological advancements led to the generation of government promoted nuclear power and an enormous government-run nuclear weapon complex. There was much secrecy surrounding nuclear materials and technology; however, there was no proper legislation to protect this technology. Prompted by the secrecy surrounding nuclear energy, The Atomic Energy Commission (hereafter AEC) was formed to develop and protect nuclear technology. The Atomic Energy Amendments Act of 1954 took precedence over previous legislation, broadening control of nuclear materials and allowing for the creation of a civilian nuclear power program (Lowenthal,1997). The Atomic Energy Act is the law that defines and restricts access to nuclear materials, and also acts as the law that endows agencies with the authority to manage and regulate nuclear materials.

Early on in the development of nuclear power, disposal of waste was recognized as an issue of concern, but received no urgency from regulatory agencies such as the AEC. However, at their request the National Academy of Sciences- National Research Council (NAS-NRC) was assigned to investigate the feasibility of land disposal of radioactive wastes. After researching the possibilities, in 1957 the NAS-NRC reported that land disposal did appear feasible in a number of locations within the US (Lowenthal, 1997 and Environment, 1997). Although salt beds and domes were suggested to present the most immediate and practical solution to the problem, research would be needed before any concrete conclusions could be reached. An early trial in disposal was executed in a salt mine in Lyons Kansas, but the project failed miserably when the site proved to be poorly chosen due to extensive drilling within the area (Lowenthal, 1997 and Environment, 1997).

The failed experiment in Lyons, brought about the perception that the AEC was far from solving the problem of radioactive wastes. "Accidents and failures with shallow burial trenches at nearly every one of the experimental AEC disposal sites, resulted from insufficient restrictions on waste streams, such as the permitting shallow burial of transuranics and unstabilized hazardous chemicals" (Lowenthal,1997). In response to these identified problems, the government incrementally introduced radioactive waste classes. The first, and only distinction between different radioactive wastes (until the 1970s) was between high level wastes (aqueous waste from the first cycle solvent extraction in reprocessing spent nuclear fuel) and other "high level wastes". That was until 1971 however, when the AEC restricted the disposal practices for transuranic wastes, which paved the way for further classification. Other waste classes were introduced by specific legislation; this incremental approach to waste classification resulted in the eclectic system of waste management (Lowenthal,1997). Please see (Tables 2-4.)

The late 1960's and early 1970's marked the passing of national environmental legislation, and saw the formation of the Environmental Protection Agency in 1970. Visible environmental issues such as brown air and burning rivers had been on both the agendas of the nation and Congress; however, now the increasing invisible threats to human health began to emerge on the agenda of Congress. Toxic-waste horror stories such as Love Canal and Times Beach turned unprecedented attention to waste disposal and cleanup with major amendments to the Solid Waste Disposal Act of 1965.Namely, the Resource Conservation and Recovery Act of 1976 and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (Lowenthal,1997). This attention reached the nuclear industry in the late 1970s beginning with legislation to address the difficult issue of uranium-mill tailings: the Uranium Mill Tailings Radiation Control Act of 1978. The Low-level Radioactive Waste Policy Act in 1980, the Nuclear Waste Policy Act in 1982, and their respective amendments soon followed this landmark in nuclear legislation (Lowenthal,1997).

The 1970s marked major changes within the regulatory sector of the nuclear industry. The AEC was broken into the Nuclear Regulatory Commission (NRC) and the Energy Resource and Development Administration (later to become the Department of Energy, DOE) by the Energy Reorganization Act of 1974 (Lowenthal, 1997 and Environment, 1997). Congress felt it would be in the best interest of the public to separate the licensing and regulation of nuclear power from the development and promotion of nuclear power. From this period until the Federal Facility Compliance Act of 1992,the AEC was responsible for standards- setting, management, execution, and regulation of its own activities. The DOE, which followed the AEC, revised its radioactive waste policies to reflect legislation. Furthermore, although the AEC descendants (DOE, and NRC) retained authority over radiation safety, "the EPA was given authority to set standards for routine emissions of radioactive materials into the air and water, and later for cleanup of contaminated sites and exposures from waste disposal sites" (Lowenthal, 1997 and Environment, 1997)..

President Carter officially deferred reprocessing of spent nuclear fuel in 1977. Until that time it was assumed that like spent military fuel, civilian spent fuel would be reprocessed to recover any of the remaining 239Pu. and fissile uranium (Lowenthal, 1997 and Environment, 1997). Carter's order was reversed once President Regan was in office, but due to the unfavorable combination of politics and economics, reprocessing spent nuclear fuel never resumed in the United States. (aside from a small amount of reprocessed fuel in West Valley, NY) Currently, all spent nuclear fuel sits at reactor sites in cooling pools or in dry concrete storage casks awaiting disposal.

As a descendent of the AEC, the DOE allowed the production of plutonium and tritium for nuclear weapons until 1991. It was then deemed that the superfluous stockpile of spent fuel was more than sufficient to supply the weapons need for the nation (Lowenthal,1997). The DOE and the Naval Nuclear Propulsion program reprocessed the highly-enriched spent fuel from naval reactors until 1992, when the DOE decided that the costs of reprocessing outweighed the benefits due partly to the diminishing demand for highly-enriched uranium.

The Nuclear Waste Policy Act Amendments of 1987 restructured the HLNW program by selecting Yucca Mountain, Nevada as the only repository site to be studied (Environment, 1997). In turn, the DOE halted all efforts to locate any future repository sites. The Yucca Mountain project was hobbled by unexpected scientific, management, intergovernmental, cost, public opposition, schedule, and regulatory compliance problems (Environment, 1997). As a result, the National Academy of Sciences Board on Radioactive Waste Management called for an over "rethinking' of the waste disposal program. The process was slow, and delayed; in fact, in 1996, Congress attempted to revise the HLNW program via Senate bill 1936, which reduces standards and regulation for Yucca Mt. This legislation was abandoned in the weeks before the election under threat of veto by President Clinton (Environment, 1997).
top

Classification Of Wastes (US)

Table 2. Definitions of radioactive waste classes acording to statutes and regulations (After Lowenthal,1997).

Waste Class

Definition

High-Level Waste

(HLW)

the highly radioactive material resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste that contains fission products in sufficient concentrations; also other highly radioactive material that the Commission, consistent with existing law, determines by rule requires permanent isolation

Spent Nuclear fuel

(SNF)

Fuel that has been withdrawn from a nuclear reactor following irradiation, the constituent elements of which have not been separated by reprocessing.

Transuranic Waste

(TRUW)

This class is specfic to waste streams from DOE and comprises "material contaminated with elements that have an atomic number greater than 92, including neptunium, plutonium, americium, and curium, and that are in concentrations greater than 10 nanocuries per gram, or in such other concentrations as the Nuclear Regulatory Commission may prescribe to protect the public health and safety." This definition was revised in 1984 by DOE Order 5820.2 to be "Without regard to source or form, waste that is contaminated with alpha-emitting transuranium radionuclides withhalf-lives greater than 20 years and concentrations greater than 100nCi/g at the time of assay."

By Product Material

Uranium Mining and Mill Tailings

"any radioactive material (except special nuclear material) yielded in or made radioactive by exposure to the radiation incident to the process of producing or utilizing special nuclear material, and the tailings or wastes produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material content."

The tailings or wastes produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material content.

Naturally Occuring and Accelerator produced Radioactive Materials

(NORM/NARM)

"Radioactive material that is not high-level radioactive waste, spent nuclear fuel, or byproduct material); and the Nuclear Regulatory Commission, consistent with existing law and in accordance with paragraph (A), classifies as low-level radioactive waste." This does not exclude commercial waste containing TRU materials. In the government sector, TRUW is excluded.

LLW is divided into two broad categories: waste that qualifies for near-surface burial, and waste that requires deeper disposal (Greater than Class C LLW, or greater confinement waste).

LLW that is regulated by the NRC and qualifies for near surface burial is separated into the three classes described in Table 2. DOE LLW is subclassified according to facility-specific limitations.


Table 3. Subclasses of low-level waste according to the NRC (After Lowenthal,1997).

LLW Waste Class

Definition

Class A

Low levels of radiation and heat, no shielding required to protect workers or public, rule of thumb states that it should decay to acceptable levels within 100y.

Class B

Has higher concentrations of radioactivity than Class A and requires greater isolation and packaging (and shielding for operations) than Class A waste.

Class C

Requires isolation from the biosphere for 500 years. Must be buried at least 5mbelow the surface and must have an engineered barrier (container and grouting).

Greater Than Class C

This is the LLW that does not qualify for near-surface burial. This includes commercial transuranics (TRUs) that have half-lives>5y and activity>100nCi/g.


Table 4. Definitions of material designations that qualify waste classifications (After Lowenthal,1997).

Material Designation

Definition

Special Nuclear Material

(SNM)

" plutonium, uranium enriched in the isotope 233 or in the isotope 235, and any other material which the Commission, pursuant to the provisions of section 2071 of [title 42 of the USC], determines to be special nuclear material, but does not include source material; or any material artificially enriched by any of the foregoing, but does not include source material."

Source Material

Material that is essential to the production of special nuclear material. "uranium, thorium, or any other material which is determined by the Commission pursuant to the provisions of section 2091 of [title 42 of the U.S.C.] to be source material; or ores containing one or more of the foregoing materials, in such concentration as the Commission may by regulation determine from time to time."

By Product Material

" any radioactive material (except special nuclear material) yielded in or made radioactive by exposure to the radiation incident to the process of producing or utilizing special nuclear material, and the tailings or wastes produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material content."

Transuranic Material

(TRU)

Material containing or contaminated with elements that have an atomic number greater than 92.

Contact Handled

(CH)

Materials or packages with a surface exposure rate < 200mR/h may be handled without shielding for radiation workers.

Remote Handeled

(RH)

Materials or packages with a surface exposure rate >200mR/h must be handled remotely for protection of radiation workers. Individual sites may have upper limits, as well

Hazardous Waste

Waste that contains both hazardous material, regulated under RCRA by the EPA, and radioactive material, regulated under the AEA and its by the NRC or DOE, is called mixed waste. There are high-level mixed wastes, low-level mixed wastes, and TRU mixed wastes (DOE treats all of its TRU waste as mixed waste). EPA has not yet determined whether SNF will be designated as mixed waste.


top

Transportation of Nuclear Waste

The U.S Department of Transportation (DOT) carries the primary burden for regulating the safe transport of radioactive materials in the United States. The DOT also sets the standards for packaging, transporting, and handling radioactive materials, including labeling, shipping-papers, loading, and unloading requirements (
DOE, 2000). A safe, dependable, transportation system is the crucial link for the operation of any proposed permanent geologic repository for the disposal of spent nuclear fuel. Over the past twenty-five years, approximately 2,500 shipments of spent nuclear fuel have been transported over America's highways, waterways, and railroads (DOE, 2000). According to the DOE (2000), an exemplary safety record has been established with no fatalities, injuries, or environmental damage caused by the radioactive nature of the cargo (HLW).

Several factors have contributed to this success. To begin, spent nuclear waste is a solid, ceramic-like material enclosed in metal tubes and shipped in dry rugged containers. These containers, which are designed by the Nuclear Regulatory Commission's (NRC) standards, are heavy sealed, thick walled, steel structures that safely confine the spent nuclear fuel (DOE, 2000). These containers are designed to protect radioactive materials from being released into the environment under both normal and accident conditions. ( Click Here for a detailed list of cask options) Since a permanent receiving HLW facility does not exist, the predicted specific routes and number of shipments can not be determined. However, if and when a permanent repository such as the proposed Yucca Mt.facility exists within legislation, the DOE will follow existing DOT regulations which limit shipments to either the interstate system, state designed alternate routes, or the rail system. Figure 3. provides a graphical representation of proposed transport routes.

Figure 2. US waste shipment routes most likely to be used to transport high level nuclear waste(HLW) to Yucca Mountain, Nevada( NWPO, 2001 )


The total costs for cross-country transportation to Yucca Mt., Nevada are estimated at $6.0 billion, of which $4.3 billion is for transport of spent nuclear fuel(SNF)from commercial sites,$0.6 billion is for SNF transport from other sites,$0.5 billion is for HLW transport from four sites in the DOE complex, and $0.6 billion is for the emergency management training for affected states, countries and tribes ( NWPO, 2001). According to the NWPO (2001) of the $4.3 billion, about $3.1 billion (71.9%) is for rail and truck carrier costs for 24,400 cask shipments over 56 million miles, about $1.0 billion (22.7%) is for purchasing, maintaining and decommissioning transportation casks and equipment, and $0.2 billion (5.4%) is for shipment escort and inspection.

The Nevada Agency for Nuclear Projects(NANP) concludes in their report, The Potential Transportation Impacts of S.104 and H.R 1270 (the Nuclear Policy Act of 1999 (NPA)) that accidents are inevitable and widespread contamination is possible. Although the DOE has claimed that shipping SNF across the country is safe, the reality is that shipping highly irradiated waste across the country through 43 states, within a half-mile of 50 million Americans is a very dangerous undertaking. The risks of shipping irradiated nuclear wastes were calculated using both DOE calculations and independent consultant analysis.

The nuclear industry falsely claims that the very small number of safely transported shipments are proof that SNF transport is feasible. However, they are neglecting that the NPA of 1999 will require in thirty years over 100,000 shipments of waste, a 4350% increase in the number of shipments to date (Public Citizen, 2000).With an such a dramatic increase in tonnage of SNF transported, one would assume that the threat of an accident would also increase. By using DOE accident rates which employ general truck and rail accident records, and considering the total miles nuclear waste will be transported, one can then calculate the number of accidents likely to occur.
 

DOE recommended accident rate

(per million miles)

Shipment Miles

(millions) over 30 years

(Planning Information Corp.)

Number of Accidents Likely to Occur

 

TRUCK

0.7-3.0

62.3

210-354

 

RAIL

11.9

14.0

 
Table 5. Predicted Nuclear Waste Transportation Accidents (Public Citizen, 2000).


According to Public Citizen, (2000) data from the DOT reveals that in the last 10 years, just under 100,000 accidents released some form of hazardous materials in the U.S and its territories. These releases caused over $300 million in damages, over 4000 minor injuries, over 350 major injuries, and over 100 deaths. Magnify these numbers by the 4350% increase in shipments of nuclear waste and SNF transportation does not appear to be a safe undertaking.

top

Storage of Nuclear Waste

Low Level Wastes (LLW) Storage and Disposal:

Low-level radioactive wastes include items that have been exposed to radioactive material or materials that have become radioactive through exposure to neutron radiation (
NRC, 2000).This waste is typically (but not limited to) contaminated protective shoe covers and clothing, wiping rags, mops, filters, reactor water treatment residues, equipment and tools, luminous dials, medical tubes, swabs, injection needles, syringes, and laboratory animal carcasses and tissues (NRC, 2000).

During the normal operation of a nuclear reactor, small amounts of radiation may be produced in or released into the water surrounding the fuel (NRC, 2000). As a result, internal components such as pipes, pumps, valves, and tools become contaminated with some of this material despite the use of filters and resins. To protect themselves, workers in contaminated areas were protective gloves, clothing, shoes, and sometimes respiratory equipment (NRC, 2000). These items become LLW and are placed in specially marked low-level container for storage or disposal.

Storage of LLW requires a NRC or Agreement State License. The regulations of either license require the wastes to be stored in a manner that keeps radiation doses to workers and members of the public below the NRC specified levels (NRC, 2000). LLW is packaged in containers appropriate to its level of hazard (see Table 3).

Figure 3.Below ground vault. Concrete storage facility with eathern cover (Murray, 1994 )


Some LLW require shielding with lead, concrete, or other materials to protect workers and members of the public. Waste containers used in the burial of LLW include carbon steel drums, liners, and boxes and high-integrity containers (HIC's)(Murty, 2000). These waste containers are placed in a disposal facility with either a soil or cement backfill. Figure 3. Carbon-steel containers are inexpensive, but can undergo both uniform corrosion and pitting corrosion within the soil and cemented systems (Murty, 2000). The life span of carbon-steel container is rather short. (only a few years or more) Therefore, steel is often used to dispose of short-lived nuclides (Murty, 2000).
HIC's represent a more durable container and are often used to dispose of long-lived radioactive waste. HIC's can be made from corrison-resistant metal alloys, reinforced concrete, high-density polyethylene(HDPE), or polymer-coated metals (Murty, 2000). A combination of both HDPE and concrete over-pack type containers are the future for HIC's. However, this type of HIC is expected to fail eventually by degradation of the concrete casing (Murty, 2000). By law, HIC's are required a minimum lifetime of 300 years by current NRC regulations ( Murty, 2000). However, all these containers can be improved for long term integrity with the addition of a concrete module.

Envirocare is currently the only LLW disposal facility that is accepting a broad range of commercial low level wastes (NRC, 2000). In the past, there have been six other disposal sites that are now closed and no longer accepting waste. They are located near or in Sheffield, Illinois; Morehead, Kentucky; Beatty, Nevada; West Valley,New York; Barnwell, South Carolina; and Richland,Washington (NRC, 2000).


Figure 4.Current and Proposed DOE LLW disposal sites (NRC, 2000).


Envirocare of Utah, is licensed by the NRC to operate a facility near Clive,Utah for the disposal of uranium mill tailings. Under a State of Utah license, the facility also accepts LLW with small concentrations of radioactive material that is generated after a facility shuts down permanently and needs to remove a large bulk of contaminated material in preparation for a license termination (NRC, 2000). Figure 4. Identifies the location of the Envirocare site, and also depicts the current and proposed disposal sites for DOE LLW. Currently all of the DOE LLW is disposed of at the Envirocare site; However, they plan to dispose of future LLW at other sites as they are made available.

High Level Waste (HLW) Storage:

After uranium fuel has been used in a reactor for 12- 18 months, it is no longer efficient in splitting atoms. and producing heat to make electricity. It is then that the fuel rods are then considered SNF and HLW(NRC, 2000). About 91,000 spent fuel assemblies, containing 26,000 tons of spent fuel from nuclear power plants are currently in storage in the United States (NRC, 2000). Of these 87,500 assemblies are stored at nuclear power plants and approximately 3,500 assemblies are stored at away-from-reactor storage facilities (NRC, 2000). About 7,000 used fuel assemblies are removed from reactors each year, and are stored until a permenant, disposal facility is made available. If all the 91,000 spent fuel assemblies currently in storage were assembled in one place, they would cover a football field about three yards high (9 ft. high)(NRC, 2000).

In the early days of nuclear power, it was planned to reprocess spent fuel to separate fission products from uranium and plutonium (Murray, 1994). However, the reprocessing of spent nuclear fuel has been prevented in the U.S since President Carter's official declaration in the 1977. The economic benefits of reprocessing fuel are marginal at best. More importantly, as public economic and political uncertainty of the nuclear industry grows, the industry has little enthusiasm for developing, licensing and construction a reprocessing plant. It is of interest, however to examine the benefits of reprocessing spent nuclear fuel. First, let us look at the composition of residues from reprocessing a metric ton (1000kg) of spent nuclear fuel (Table 6.). As one can see, the waste material is one-tenth of the weight of spent fuel. Unfortunately, most of the radioactivity is from fission products, and thus the activity per gram of waste is considerably higher (Murray, 1994). By means of current chemical technology, or an extension built on research, there is a possibility of isolating some of the radionuclides that dominate the performance of a repository. Removal of both the shorter-lived lived heat producers and longer-lived hazardous isotopes might make the disposal process simpler, easier, and safer and more acceptable (Murray, 1994).

Among the objections to reprocessing plants, is the possibility of plutonium becoming more accessible for illegal purposes including the manufacturing of nuclear weapons and the threat of terrorism (Murray, 1994). Another reason for not treating SNF is the increase in radiation exposure to workers required to operate and maintain the reprocessing facility.

Material

Weight ,kg.

Fission Products

28.8

Uranium

4.8

Plutonium

0.04

Neptinium

0.48

Americum

0.14

Curium

0.04

Reprocessing Chemicals

68.5

Total

102.8

Table 6. Composition of residues from reprocessing (Murray, 1994).

Methods of Storage:

With no reprocessing operations, all generated HLW is in storage awaiting a permanent burial ground. There are two typical methods for storing HLW. Currently, most SNF is "safely" stored in special designed pools at individual reactor sites (NRC, 2000). A typical wet storage pool, store spent fuel rods under at least 20 feet of water, which provides adequate shielding for anyone near the storage area (NRC, 2000). A typical spent fuel rod is about twelve feet long and 3/4 inches in diameter. The rods are arranged in a square configuration known as a fuel assembly. The assemblies range in size from an array of 6 rods by 6 rods, or a 17 rods x 17 rods (NRC, 2000). The fuel pools vary in size from a capacity of 216 to 8,083 fuel assemblies. These storage pools were originally designed to store several years of spent fuel (NRC, 2000). However, with delays in developing disposal facilities for spent fuel, licensees have redesigned and rebuilt equipment in the pools to accommodate a greater amount of fuel rods to be stored. This storage option is limited, however, because the facility needs to keep individual fuel rods from coming into contact with one another and initiating a nuclear reaction (NRC, 2000).
Figure 5. Typical storage pool at a nuclear reactor
(Murray, 1994).


Dry Storage

If and when pool capacity is reached, licensees may move toward use of aboveground dry storage casks (NRC, 2000). In this method, spent fuel is surrounded by inert gas inside a container called a cask. To date, the NRC has approved 12 spent fuel casks which are listed in the provided regulations. The casks can be made of metal or concrete, and some can be used for both storage and transportation (NRC, 2000). The storage casks are found within the envelope of the previously approved nuclear power site, and are either placed horizontally, or stand vertically on a concrete pad. All casks used for storage must be approved by the NRC; furthermore, the casks must be designed to resist events such as floods, tornadoes, temperature extremes, earthquakes and even missiles (NRC, 2000). Dry storage casks house SNF that has been previously cooled in a storage pool and is at least five years of age. Typically, the maximum heat generated from the 24 fuel assemblies stored in each cask is less than that given off by 240 100-watt light bulbs (NRC, 2000). Nine nuclear power plants are currently storing spent fuel under the dry storage option.

Figure 6. Typical dry cask storage container NRC, 2000).

top

Proposed Yucca Mountain Storage Facility

Figure 7.The proposed Yucca Mountain storage facility (Zahn, 1998.)


The Nuclear Waste Policy Amendments Act of 1987, designated the Yucca Mountain site in Nevada as the only location to be studied for possible development as a permanent geologic repository (Mielke, 1999). Yucca Mt. is located in southern Nevada about 100 miles northwest of Las Vegas. The mountain (Figure 6.) is best described as a ridge, about 18 miles long, jutting several hundred meters above the surrounding lands (Mielke, 1999). It is an arid region of mountains and valleys, with sparse vegetation, low rainfall, (less than 6 inches a year) and a very limited population. Yucca Mt. lies adjacent to and partly within the previous Nevada test site where hundreds of underground nuclear tests have been performed (Mielke, 1999).

The design for the repository at Yucca Mt. includes more than 160 kilometers of tunnels (Figure 8.), approximately 980 ft. below the surface and spread out over about 2.2 square miles (Mielke, 1999). Congress has limited the amount of HLW that can be placed into the repository to 70,000 metric tons, which will consist of 62,000 metric tons of spent nuclear fuel in 25,000 waste containers and 8,000 metric tons of defense high-level waste in approximately 15,000 waste containers (Mielke, 1999). DOE plans call for waste containers to be placed into boreholes within the repository by a shielded transporter and covered with rock or shielding. The heat released from radioactive decay can be controlled through mixing the ages of the fuels loaded into the containers, and also by maintaining appropriate spacing between waste packages in the repository (Mielke, 1999).

Figure 8. The "Starter Tunnel" for the underground Exploratory Studies Facility (ESF)located at the eastern base of Yucca Mountain (Sandia National Laboratories, 1995.)


The DOE and NRC claim that the risks from the repository will be "as negligible as it is possible to imagine" (Science, 1991). However, although the NRC and other governmental agencies have been pushing for the siting and construction of a permanent geologic nuclear waste facility at Yucca Mountain, they have encountered overwhelming opposition from both the scientific community and a concerned public. According to an article in Science (1991) a number of events have arisen in the past several years which underscore the controversy:

"Official opposition by the State of Nevada has increased substantially. In June 1989, the Nevada legislature passed Assembly Bill 222, making it unlawful for any person or governmental entity to store high-level radioactive waste in the state. The state attorney general subsequently issued an opinion that the Yucca Mountain site had been effectively vetoed under a provision of the Nuclear Waste Policy Act. The governor instructed state agencies to disregard DOE's applications for environmental permits necessary to investigate the site. The state and DOE initiated federal lawsuits over continuance of the program and issuance of the permits needed for on-site studies. In September 1990, the 9th U.S. Circuit Court of Appeals ruled that the state had acted improperly and ordered Nevada officials to issue the permits. Nevada appealed to the Supreme Court, which let stand the prior ruling. Although state officials have, under duress, begun to accept and process DOE permit applications, the governor and other elected officials have announced that their opposition to the repository will not diminish.

In November 1989, DOE, admitting dissatisfaction with its technical assessments of the Yucca Mountain site, announced that it would essentially start over with, "for the first time," an integrated, responsible plan. This plan would subject technical studies to close outside scrutiny to ensure that decisions about Yucca Mountain would be made "solely on the basis of solid scientific evidence"

In July 1990, the National Research Council's Board on Radioactive Waste Management issued a strong critique of the DOE program, charging that DOE's insistence on doing everything right the first time has misled the public by promising unattainable levels of safety under a rigid schedule that is "... unrealistic, given the inherent uncertainties of this unprecedented undertaking," and thus vulnerable to "'show stopping' problems and delays that could lead to a further deterioration of public and scientific trust" The board recommended, instead, a more flexible approach, permitting design and engineering changes as new information becomes available during repository construction and operation".

The Viability Assessment
The viability assessment presents the result's of DOE's Yucca Mountain Site Characterization Project thus far, and identifies the critical issues that need to be addressed. Based on their Viability Assessment, the DOE believes that Yucca Mt. remains a promising site for a geologic repository (NRC, 2000). Uncertainties remain about key natural processes, the preliminary design, and how the site and design would interact. To address these uncertainties, the DOE plans to improve preliminary design, complete critical tests and analyses, and prepare a final Environmental Impact Statement (NRC, 2000). The question remains, how certain is the DOE that this site is suitable, if tests have not yet been completed? What type of data are they producing, and what is it showing?
Apparently, according to the DOE the site is most definitely suitable. However, an additional report submitted by six experts hired by the DOE to peer review the Repository System Performance Assessment raised some doubts about the conclusions presented in the viability assessment (NRC, 2000). The Peer Review report faults the DOE's current model for predicting the repository's behavior, which takes into account everything affecting the movement of radioactive elements out of the fuel rods and into the environment over the next millennia.

Major Concerns

The are many concerns over the siting of the Yucca Mountain facility. The largest concern, of course, is the release of radioactive materials into the environment. The DOE and its advocates ensure that the heat generated from the radioactive decay will keep the repository dry and safe. However, it is inevitable that condensation will build up in the tunnels, corroding the casks, which hold HLW. As time passes, these canisters will inherently fail. In addition to the obvious, there are also numerous other inherent dangers.

Seismic Stability: (After NRC,2000)

  • Yucca Mountain is bounded by several Quaternary faults, and is composed of series of north-trending structural blocks that have been tilted eastward along west dipping high angle faults. The proposed repository is within one of these blocks.


  • 32 faults have been identified within a 2,600 square-kilometer area that encompasses Yucca Mountain


  • On6/29/92, an earthquake occurred about twelve miles from the site, causing damage to several DOE buildings on site


  • The Ghost Dance Fault cuts directly through the repository


  • The DOE can not predict the future. The likelihood of an earthquake within the repository can never be ruled out.


  • Volcanic Activity:( after NIRS, 2000 and Mielke, 1999)

  • There are young lava cones surrounding the mountain. This is clear evidence of the possibility of a magma pocket which the earth's crust is slowly moving.


  • Global positioning satellites confirm that the earth's crust at Yucca Mt. is expanding.


  • Recent small-volume basaltic volcanism is present in the vicinity of Yucca Mt.


  • The Lanthorp Wells cinder cone is within 15 kilometers of the repository. It has erupted in the past 140,000-200,000 years


  • Volcanism is the most credible intrusion factor scenario during the post-closure period.


  • Hydrology:( After Mielke, 1999 and Carter, 1998)

  • The discovery of traces of chlorine-36, an isotope created by nuclear tests in the Nevada desert in the 1950s, in fracture coatings in and below the repository level indicated that rainwater seeping through cracks and fractures had carried the isotope through 250 meters of rock in less that 50 years. This is much faster than scientists had predicted, and has caused DOE to develop a new model depicting more rapid flow through fractures in the unsaturated zone.


  • Calculations based on the DOE's latest published performance assessment indicate that a contaminated plume would begin to form within the first 5,000 years of the repository being sealed


  • Mountain Project planners generally assume that the plume will first take on the general outline of the repository, about 2.2 miles wide. Advancing at a rate of about 30-ft a year, after 7,000 years the plume will pass beneath U.S 95 at a point near the hamlet of Lathorp Wells. After 7,500 years, it will reach the first farm well in the Amargosa Valley. After about 11,000 years or so, the plume will have traveled 40+ miles and reached its final destination of Franklin Lake Playa, where the aquifer reaches the surface


  • Radioistope Transport:( After Mielke, 1998 )

  • Retardation factors are used to quantify the potential of specific radionuclides to sorb, or bind, onto specific mineral surfaces. For a given porous material saturated with water containing a concentration of a specific radionuclide, a retardation factor can be determined in a laboratory experiment


  • It is known that highly fractured regions exist and can carry most of the flow. Estimates of how much sorption and retardation will occur in these highly transmissive regions are uncertain. The bulk of the flow may effectively bypass sorptive minerals unless they extensively coat fracture surfaces.


  • Over the long time period envisioned, water percolating through the repository could penetrate a waste package and contact waste materials. Water may transport radionuclides either in suspension, bound to very small particles known as colloids, or m solution (i.e. as a dissolved solid). Colloid particles are small enough to travel with flowing water through fractures and the matrix of the rock, and certain colloids also have the ability to bind radionuclides to their surfaces. Colloid transport of certain nuclides, such as plutonium, could result in relatively fast transport.



  • Conclusion


    By the year 2035, after all existing nuclear plants have completed 40 years of operation, there will be approximately 85,000 metric tons of SNF (
    NRC, 2000). The U.S.DOE has been under intense pressure from Congress and the nuclear industry to dispose of this accumulating volume of high-level waste since the passage of the Nuclear Waste Policy Act in 1982 and its amendment in 1987, which limited site selection to Yucca Mt., Nevada. The lack of a suitable solution to the waste problem is widely viewed as an obstacle to further development of nuclear power and a threat to the continued operation of existing reactors, besides being a safety hazard in its own right.

    Yet, at this time, the DOE program has been brought nearly to a halt by overwhelming political opposition, fueled by perceptions of the public that the risks are immense . These perceptions stand in stark contrast to the prevailing view of the technical community, which argues that nuclear wastes can be disposed of safely, in deep underground isolation. Officials from DOE, the nuclear industry, and their technical experts are profoundly puzzled, frustrated, and disturbed by public and political opposition and consider many objections to be based on irrationality and ignorance. However, this page is based on confirmed scientific research. I would like to challenge the nuclear industry to prove otherwise. Please take the time, and the action to show both the DOE and the NRC that the public is educated ( see What you can do).


    References

    Carter, Luther and Pigford, Thomas.1998. Getting Yucca Mountain right. Science v54 p56(6)

    Department of Energy, 2000. News and Publications. Rceived from the World Wide Web on 3/29/01.www.nv.doe.gov/Default.htm

    Energy Information Administration, 2000.EIA Reports. Received from the World Wide Web on 1/27/2001: http://www.eia.doe.gov/neic/press/press152.html

    Edgerson,Charles. April,1997. A history of high-level nuclear waste disposal efforts. Environment,v39. n3. p10(1)

    Lowenthal,Micah D.,1997. Radioactive Waste Classification in the United States: History and Current Predicaments. Received from the World Wide Web on 1/28/2001:http://www.nuc.berkeley.edu/cnwm/reports/RE97-0001/

    Mielke E. James.1999. Proposed high level nuclear waste repository: Yucca Mountain site characterization progress. Received from the World Wide Web on 4/2/2001: http://www.cnie.org/nle/waste-30.html

    Murray, Raymond L.Understanding Radioactive Waste. Battelle Press, Columbus,Oh. p.126.

    Murty,Linga K. and Yim, Man-Sung. Materials Issues in Nuclear Waste Management. JOM, 52(9) pp.26-29

    Nuclear Information and Resource Service. Received from the World Wide Web on 3/19/01: http://www.nirs.org/dontwasteamerica/whyyuccawillleak.htm

    Nuclear Regulatory Commission, 2000. Radioactive Waste Production, Storage, Disposal. Received from the World WIde Web on 3/11/2001:http://www.nrc.gov/NRC/NUREGS/BR0216/br0216.html#1Contents

    Public Citizen. 1999. Received from the World Wide Web on 3/19/01: http://www.citizen.org

    Sandia National Laboratories, 1995. Yucca MountainProject Overview. Received from the World Wide Web on 2/1/2001:http://www.nwer.sandia.gov/ymp/over01.html

    Slovic Paul; Layman, Mark; Flynn, H. James.1991. Perceived risk, trust, and the politics of nuclear waste. Science v254 p1603(5)

    StarNine,1996. WebStar. Recived from the World Wide Web on 3/13/2001:http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/u235chn.html

    The State of Nevada, 2001. Nuclear Waste Project Office. Nuclear Waste Transportation Routes. Retrieved on 1 Feb 2001 from the World Wide Web:http://www.state.nv.us/nucwaste/states/us.htm

    The State of Nevada, 2001. The Results, Uncertainties,and Implications of the Independent Cost Assessment. Received from the World Wide Web:http://www.state.nv.us/nucwaste/trans/pic2/2pic02.htm

    Uranium Institute, 2001. Received from the World Wide Web on 1/19/2001: http://www.uilondon.org/.

    Uranium Information Centre, 2001.What is Uranium? Received from the World Wide Web on 2/6/2001:http://www.uic.com.au/uran.htm.

    Zahn, Martin.1998.Curriculum Module Investigating the Characteristics of High Level Nuclear Waste and the Problems Involved in the Long Term , Safe Storage of These Materials. Received from the World Wide Web on 2/1/2000:http://earth.fhda.edu/curriculum/nuclear/home.htm#Table%20of%20Contents

    top