|"How SAFE are radioactive material transportation packages?"|
History of Radioactive Material Packages that Transport High Level Radioactive Waste (HLW)
Background of High Level Radioactive Waste [ TOP ] [ NEXT ]
HLW, consists primarily of nuclear fuel rods from commercial nuclear power plants
and is called spent nuclear fuel. Radioactive waste that results from the commercial reprocessing of spent nuclear
fuel also falls under the NRC's definition of HLW. Reprocessing extracts isotopes from spent fuel that can be used
again as reactor fuel. Commercial reprocessing is currently not practiced in the US although it has been allowed in the
past. There are significant quantities of HLW from the defense reprocessing and commercial nuclear programs at
Department of Energy (DOE) facilities, such as Hanford, Washington, Savannah River, South Carolina, and West
Valley, New York, that must also be included in any HLW disposal plans.
Legislative Requirements [ TOP ] [ PREVIOUS ] [ NEXT ]
U.S. policies governing the permanent disposal of HLW are defined by the Nuclear Waste Policy Act of 1982 (NWPA), the Nuclear Waste Policy Amendments Act (NWPAA) of 1987, and the Energy Policy Act of 1992. These acts specify that HLW will be disposed of underground, in a deep geologic repository.
The NRC is one of three Federal agencies under the acts with a role in the disposal of spent fuel and other HLW. DOE is responsible for determining the suitability of the proposed disposal site as well as developing, building, and operating the geologic repository. The U.S. Environmental Protection Agency (EPA) will develop environmental standards to evaluate the safety of the geologic repository proposed by DOE. NRC will license the repository after determining whether DOE's proposed repository site and design comply with EPA's standards and with NRC's implementing regulations found in 10 CFR Part 60.
Congress, in NWPAA, has designated Yucca Mountain as the single candidate site for characterization as a potential geologic repository. This does not mean Yucca Mountain has been selected for a repository, but it will be the only site thoroughly examined at this time. Site characterization involves field, laboratory exploration, and research to establish the geologic conditions at the site, and the ranges of those conditions. It includes surface-based mapping, exploratory drilling, and construction of an underground exploratory studies facility, essentially a large tunnel excavated at the location and in the rock where the actual repository would be.
Following site characterization, DOE is required by NWPA to prepare a recommendation of a potential site as a candidate for a geologic repository. This will be either Yucca Mountain or another site if Yucca Mountain is determined to be unsuitable. This recommendation, which DOE will submit to the President and then to Congress, is to include the preliminary comments of NRC concerning the extent to which site characterization and the waste form proposal for the recommended site seem sufficient for inclusion in any potential license application.
If the site is approved by the President and Congress, NWPA specifies that licensing of a geologic repository will occur in three phases. In the first phase, following site characterization, DOE would apply to the NRC for authorization to construct a geologic repository. Once a construction authorization request is submitted, by law, NRC will have three years to perform its review, conduct a public hearing, and reach a construction authorization decision by an independent Licensing Board. To comply with this schedule, NRC is already reviewing DOE's site characterization activities and investigations to identify and resolve potential licensing issues. However, during the licensing proceeding itself, all issues, including those previously resolved, can potentially be reopened by the Licensing Board and become issues of contention during the hearing.
In the second phase, as construction of the repository nears completion, DOE will request a license to receive HLW. If NRC grants that license, DOE will begin placing HLW into the repository. In the third phase, when the repository is full, DOE will apply for a license amendment to decommission and permanently close the disposal facility.
Regulatory Framework [ TOP ] [ PREVIOUS ] [ NEXT ]
The NWPA directed both the EPA and the NRC to publish standards and criteria for the storage and disposal of HLW. The applicable EPA environmental standards and the current NRC implementing regulations are found, respectively, at 40 CFR Part 191 and 10 CFR Part 60. Both regulations, as described below, are subject to revision through new legislation. NRC's role in licensing a geologic repository has two objectives. The first is to ensure that DOE has complied with the applicable standards, and the second is to ensure that public health and safety has been adequately protected.
NRC's geologic disposal regulation is structured around a concept of the multiple barriers and the Commission's principals of defense-in-depth, and primarily focuses on the performance objectives for the repository. NRC produced the regulation in the early 1980's and it contains technical requirements, contents of a potential license application, quality assurance, and consultation with States, Indian Tribes, and affected local governments. Part 60 does not prescribe specific criteria for site suitability. However, it does identify factors for considering potential sites. For example, if potentially adverse conditions are identified, DOE must demonstrate that the conditions can be compensated for by the repository design or by other favorable site conditions. The regulation is written to favor the selection of a candidate site with certain waste isolation capabilities. However, it is DOE's responsibility to select an appropriate site and design an adequate repository.
The EPA issued general environmental standards for a HLW repository in 1985. The NWPA permitted NRC to publish its regulations before EPA; however, NRC's regulations must be consistent with EPA standards. The EPA, in 40 CFR Part 191, established specific limits on the release of radioactive material from the repository during 10,000 years following the permanent closure of the repository. NRC regulations are consistent with this requirement.
In March 1986, several petitions for review of EPA regulations were filed by a number of States and environmental groups. They were consolidated in the U.S. Court of Appeals for the First Circuit Court in Boston. In July 1987, the court remanded the standard to EPA for reconsideration of several of its provisions. Principal among these was Subpart B, the individual and ground water protection requirements. The Court requested further notice and comment on these provisions as well as their interrelationship to EPA's requirements under the Safe Drinking Water Act.
In October 1992, the Waste Isolation Pilot Project Land Withdrawal Act was enacted, which reinstated all of the EPA's regulations except those provisions that were the subject of the remand by the First Circuit. Moreover, the Act also required issuance of new standards to address those that were the subject of the judicial remand and exempted the Yucca Mountain site from EPA's Part 191 standards. Final disposal standards in 40 CFR Part 191, for sites other than Yucca Mountain, were issued in December 1993.
Since then, EPA has been revising its standards for the Yucca Mountain site. However, in late 1992, Congress passed the Energy Policy Act which required EPA to contract with the National Academy of Sciences to conduct a study on specific aspects of these standards. The Academy completed its deliberations and issued findings and recommendations in August of 1995. The EPA now must issue environmental standards for Yucca Mountain that reflect these findings and recommendations. After EPA issues its standards, NRC must revise its regulations to be consistent with them.
Important differences exist between these findings and recommendations and prior EPA standards for HLW as well as the existing geologic disposal regulations. A key recommendation from the Academy was that the revised standard limit individual risk to a member of the public and in doing so, abandon the existing quantitative release limit with its implied population-protection basis. Specifically, the Academy has recommended that the level of protection provided for in the new environmental standard should be comparable to that level of risk that may be acceptable to society at large. The Academy stated society currently tolerates involuntary risks such as accidental deaths from automobile, airplane crashes or drowning, of about 1-in-100,000 to 1-in-1,000,000 per year. To demonstrate that the geologic repository can be designed to provide comparable protection to society, the Academy recommended that assessments of individual risks be conducted for certain target populations of people, in the Yucca Mountain vicinity, using the "critical group" approach specified by the International Commission on Radiological Protection.
The NRC has been reviewing selected technical aspects of the Academy's recommendations. These reviews support ongoing NRC staff interactions with EPA and others during the development of environmental standards and conforming rulemaking. The NRC is cooperating with EPA to develop implementable HLW standards that consider the recommendations of the NAS. Once EPA issues its final standards, NRC must produce conforming regulations within one year. The NRC anticipates that EPA will propose new standards specific to Yucca Mountain, tentatively designated 40 CFR Part 197, sometime in 1999.
Site Characterization Activities [ TOP ] [ PREVIOUS ] [ NEXT ]
The DOE's 1988 Site Characterization Plan for Yucca Mountain established the initial basis for the many engineering and scientific investigations of the site. It has been conducting site characterization to gather enough information about the Yucca Mountain site to evaluate the waste isolation capabilities. In 1991, the State of Nevada granted DOE the permits necessary to proceed with certain site characterization activities. These activities included the excavation of test pits and trenches, drilling boreholes, and monitoring ground water.
In September 1994, DOE began excavation of the exploratory studies facility using a tunnel boring machine. The initial design called for a continuous tunnel 7.6 meters (25 feet) in diameter. The tunnel was completed in April 1997. It begins at the North Portal and extends west approximately 2000 meters (1.24 miles) into a 90 degree turn. This leads to a main tunnel, at a depth of 300 meters (984 feet) below the surface, which extends south approximately 3000 meters (1.86 miles), ending in a second 90 degree turn. From this turn the tunnel travels east about 1300 meters (0.8 miles) and emerges at the South Portal. The tunnel machine has bored through a series of geologic features including a structural feature known as the Bow Ridge Fault. Within the tunnel are seven testing alcoves and four test niches that are being used to investigate the hydrologic, hydrochemical, and thermo-mechanical properties of the rocks underlying Yucca Mountain.
In December 1997, DOE began excavation of a smaller exploratory tunnel (5.5 meters/18 feet) as an extension of the main tunnel. This so-called "east-west" or "cross" drift will run perpendicular to the existing tunnel, beginning to the west of the Bow Ridge Fault. It is expected to be about 1300 meters (0.8 miles) in length and end near the Solitario Canyon Fault. The cross-drift will also contain instrumentation for scientific tests and should provide additional data on the sub-surface geology of Yucca Mountain to the west of the main tunnel.
Current Status of DOE Program [ TOP ] [ PREVIOUS ] [ NEXT ]
In the mid-1990's, Congress provided additional focus and redirection to the national HLW program. As a result, DOE implemented its new Program Approach for streamlining site characterization in the spring of 1995, which included provisions for interacting with the NRC. However, budget allocations for fiscal year 1996 (10/1/95-9/30/96), were insufficient to support the Program Approach. DOE subsequently developed an alternative plan to prepare a Viability Assessment. This Assessment has four key elements:
Under DOE's current Program Approach, the development of the Yucca Mountain site involves several sequential activities. The Viability Assessment, to be completed in 1998, will be the basis for a DOE decision on whether to continue with the development of Yucca Mountain as a HLW repository. If requested to comment on DOE's Viability Assessment by the Congress or the President, NRC expects to address the technical quality of DOE's work, the extent to which issues appear to have been resolved, and NRC views on remaining work by DOE necessary for submission of a successful application for construction authorization. The NRC also intends to comment on the reasonableness of DOE's projected schedule for licensing.
Should DOE decide to proceed, the current schedule calls for a decision on site suitability in 1999 and a recommendation to the President in 2001. Next would come the development and submission of a license application, in 2002, to NRC for authorization to construct the repository. If NRC authorizes construction, following completion of repository construction, DOE would apply to NRC for a license to receive and possess spent fuel and other HLW. If the site is determined to be suitable and licensable for disposal of spent fuel, it would be available for disposal activities in 2010.
DOE plans to complete its Viability Assessment in the fall of 1998. The Viability Assessment was originally intended as a decision-making tool for DOE and was not required by law, as is the case with the site suitability determination. However, DOE's FY1997 appropriations bill required DOE to submit its Viability Assessment to Congress in late 1998. Moreover, a Viability Assessment is now required in pending Congressional legislation.
Current Status of NRC Program [ TOP ] [ PREVIOUS ]
Initially one of NRC's primary responsibilities is to review DOE's site characterization program and associated activities and to identify any specific concerns that may impact licensing. In addition, the NRC observes site characterization activities in the field, such as exploratory drilling and tunneling, and monitors DOE quality assurance audits. All consultation activities are open to participation by the State of Nevada, Indian Tribes, and local governments.
Significant budget reductions and changes to DOE's program stimulated restructuring the NRC program around the following 10 Key Technical Issues:
The NRC continues to discuss resolution of the key issues and give DOE feedback prior to publication of its Viability Assessment. An agreement is in place between NRC and DOE on a performance-based program and on the potential significance of the ten key technical issues. However, budget reductions resulted in the elimination of contractor support in Radionuclide Transport, Container Life and Source Term, and Repository Design and Thermal Mechanical Effects, so that only limited progress toward issue resolution was made in these three areas.
Issue resolution progress reports are used to document resolution of the key issues. They describe the subissues, their importance to repository performance, acceptance criteria that are the basis for determining resolution, and the status of resolution. Subissues have been resolved, although no key technical issue is fully resolved. The NRC has completed a prototype progress report on climate change as well as for issues #2, 3, 5, 6 & 7.
In addition to preparing the issue resolution progress reports, technical exchanges and feedback to DOE also contributed to issue resolution and resulted in the following:
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