Background

Early History of Radioactive Waste Management

References:

• Managing the Nation’s Commercial High-Level Radioactive Waste (Washington, DC: U.S. Congress, Office of Technology Assessment, OTA-O-171, March 1985).
  

• 1946: Atomic Energy Act establishes the Atomic Energy Commission (AEC) with the goal of promoting and regulating nuclear energy
  
  
• 1954: Legislation opens nuclear power industry to private enterprise.
  
  
• In the 1950s and 1960s, the issue of nuclear waste disposal was considered a technical problem that could be resolved using existing technology.  Daniel Metlay, a former member of the Nuclear Waste Technical Review Board (NWTRB), characterized the prevailing view as “an illusion of certainty…where, in reality, none existed.”  Policymakers operated on an unquestioned assumption that when spent nuclear fuel (SNF) and high-level waste (HLW) needed to be disposed of, the technical means to do so would be relatively easy to achieve.  As a result, the organizational and technical infrastructure needed for radioactive waste disposal remained underdeveloped.
  
  
• An important consideration in disposing of SNF is whether to reprocess the fuel first.  Reprocessing SNF can recover plutonium and unreacted uranium, which can then be used in the production of more nuclear fuel.  The remaining high-level waste consists of highly radioactive fission products and long-lived transuranics, which are solidified before disposal.  The first commercial SNF reprocessing center, the Nuclear Fuel Services Facility, was built at West Valley, NY in 1966.  It operated until 1972 when it was closed down to under go modifications to meet new safety regulations.  It never reopened.  During its six-year tenure, the plant operated below capacity and experience a number of safety issues.  Two more facilities were planned, one of which was built, but neither ever operated.  In part, this was due to an indefinite moratorium on commercial SNF reprocessing under the Carter administration in 1977.
  
  
• In 1957, the National Academy of Sciences (NAS) published a report recommending that nuclear waste be dissolved in low concentrations in liquid and disposed of in stable salt formations.  Salt formations are advantageous because the presence of salt of a geologic time scale indicates little movement of water through the area and any transport of waste from the repository through fractures would be inhibited by the self-sealing, plastic nature of salt deposits.
  
  
• Over the next 20 years, the AEC studied potential sites for placement of a repository and most of these sites contained salt deposits.  In 1970, the AEC announced that a salt mine in Lyons, Kansas would house the first geologic repository, despite a lack on consensus on the issue from state and local officials.  Two years later, AEC abandoned plans for a repository at Lyons due to uncertainty that site would perform safely.
  
  
• 1974: The Energy Reorganization Act abolishes the AEC giving the function of developing nuclear energy to the Energy Research and Development Agency (ERDA), which later became the Department of Energy (DOE), and the regulatory functions to the Nuclear Regulatory Commission (USNRC).
  
  
• In 1974, the ERDA selected a salt deposit near Carlsbad, New Mexico for disposal of low-level transuranic waste.  The Waste Isolation Pilot Plant (WIPP) promised to bring jobs to what was a depressed local economy.  When plans to store HLW at WIPP were introduced in 1977, WIPP’s invitation was nearly revoked by the New Mexico House of Representatives and as a result, the DOE promised New Mexico veto rights over WIPP.  The DOE made later attempts to change the nature of WIPP and lawsuits brought by the state and other organizations attempted to nullify this change and prevent the repository from opening.  After 25 years of research and political haggling, WIPP began receiving shipments of transuranic waste in early 1999.
  
  
• Initiated by the ERDA in 1975, the National Waste Terminal Storage (NWTS) program began a survey of geologic formations in 36 states.  NWTS expanded the scope of potential sites to include other geologic media such as basalt and volcanic tuff.  In addition, the geology of potential sites was considered alongside engineered barriers to waste transport, such as the waste canister.  By 1980, research was being conducted as sites in a number of states including Louisiana, Texas, Washington, and Nevada.

Political Complications:

• Beginning in the 1970’s, a number of states began passing legislation that forbade the disposal of HLW on their land.  These states worried that they would bear a disproportionate brunt of the nation’s nuclear waste by housing a repository.  The rational was that if waste started coming, it wouldn’t stop.  Other states feared that if they didn’t follow suit with similar legislation, they would end up with a repository by default.  The environmental and economic impacts of a repository were also important concerns.  These concerns were heightened when it became apparent that the federal government rarely stuck to any specific policy or schedule.  Essentially, “states…had developed strong doubts that the Federal Government could be counted on to keep its word on waste management matters.” (OTA 1985) 
  
  
• In addition to distrust on the part of the states, the nuclear power industry and environmental groups were also wary of any decisions made by the DOE.  The nuclear power industry has been a powerful political force in the effort to site and build a repository for SNF.   Without permanent storage facilities, reactors will use all of their available, on-site temporary storage and will be forced to shutdown.  Building more short-term storage would allow the federal government more time to resolve issues concerning a permanent geologic repository and would keep nuclear power plants open.  Some who see the easy availability of short-term storage as a way to decrease pressure on the effort to find a permanent solution oppose this approach.  Thus, the DOE faces political pressure in both directions, to delay and to proceed with all available haste.

The Nuclear Waste Policy Act (NWPA) and Standards for Yucca Mountain

Additional references:

• Nuclear Waste: Technical, Schedule, and Cost Uncertainties of the Yucca Mountain Repository Project (Washington, DC: U.S. Congress, General Accounting Office, GAO-02-191, December 2001).
• Final Public Health and Environmental Radiation Protection Standards For Yucca Mountain Nevada (Washington, DC: U.S. Environmental Protection Agency, 40 CFR Part 197, 2001).

• The Nuclear Waste Policy Act of 1982 establishes a schedule and framework for siting and building one or more geologic repositories as the permanent home of the nation’s SNF and HLW.  The DOE was charged with investigating three possible sites: a salt formation in Texas, basalt formations at Hanford, Washington, and volcanic tuff at Yucca Mountain, Nevada.  In addition, the DOE was responsible for recommending one site to the President, who could then approve the site, which would allow the DOE to apply to the USNRC for a construction license.  The EPA was given the responsibility of drafting health and safety standards for waste repositories.  General repository standards appeared in September 1985 and standards specific to Yucca Mountain appeared in June 2001.  In evaluating DOE’s application for a construction license, the USNRC is required to make sure the repository meets the EPA standards.
  
  
• In 1987, the Nuclear Waste Policy Act Amendments were passed and the DOE was obligated to investigate only one potential repository site, Yucca Mountain.  In addition, the Nuclear Waste Technology Review Board (NWTRB) was created in order to review the technical and scientific validity of the DOE’s investigation of storing and transporting waste to Yucca Mountain and mandated to report its findings twice a year to Congress.
  
  
• In 1985, the EPA drafted health and safety standards applicable to all geologic repositories and transportation of SNF, HLW, and transuranics (40 CFR part 191).  This rule set limits on the total amount of radionuclides that may enter the environment for the next 10,000 years, limited the acceptable health risk to 1,000 fatal cancers over the 10,000 year period, set individual protection requirements for members of the public for 1,000 years, and established ground water standards for 1,000 years.
  
  
• In 1987, the U.S. Court of Appeals remanded some of the disposal standards for further consideration by the EPA.  In particular, the court was wary of the 1,000-year time frame for the individual protection standard.  In 1992, the WIPP Land Withdrawal Act reinstated 40 CFR part 191, except for the portions found objectionable by the court.  The WIPP Land Withdrawal Act also required that the EPA issue standards to replace the ones thrown out by the court and exempted Yucca Mountain from 40 CFR part 191 disposal standards.  The EPA released the revised 40 CFR par 191 in December 1993.
  
  
• In 1992, the Energy Policy Act (EnPA) detailed the responsibilities of the EPA with respect to Yucca Mountain.  EPA was mandated to set health and safety standards for the proposed repository (specifically to “prescribe the maximum annual effective dose equivalent to individual members of the public.” (EnPA section 801(a)(1)), contract with the NAS to conduct a study to determine reasonable standards for the protection of public health, and to ensure that their standards were consistent the NAS’s findings and recommendations.  Based on the resulting 1995 NAS report and the previous standards contained in 40 CFR part 191, EPA released Yucca Mountain standards, 40 CFR part 197, in June 2001.  These standards are similar to 40 CFR part 191 in that they provide an individual protection standard (in the form of a dose-based standard) and a groundwater protection standard.  The dose limit is 15 mrem/yr for a reasonably maximally exposed individual, which corresponds to 8.5 chances in 1,000,000 of contracting a fatal cancer per year.  They also add a human-intrusion standard, which applies in the event that human beings unintentionally drill into the repository at some future point in time.    In addition, the standards define a “controlled area” where dose limits do not apply.  The controlled area is centered on the repository and the reasonably maximally exposed individual is located at the edge of the controlled area.

Total System Performance Assessment (TSPA) Methodology: Evaluating How Yucca Mountain Complies to EPA standards

Additional references:

• Total System Performance Assessment for the Site Recommendation (TSPA-SR). (Las Vegas, Nevada: Civilian Radioactive Waste Management, TDR-WIS-PA-000001 REV 00 ICN 01, 2000).
• National Research Council, Board on Radioactive Waste Management. 2001. Disposition of High-Level Waste and Spent Nuclear Fuel: The Continuing Societal and Technical Challenges. Washington, D.C.: National Academy Press.

• The TSPA method used by the DOE is representative of a safety assessment methodology, performance assessment, that has developed over the past 20 years.  Performance assessments are used to make quantified estimates about the future behavior of a repository and to measure the uncertainty in these estimates.  The DOE specifically defines the role of TSPA as a way “to provide a defensible analysis of system behavior incorporating models and parameters that are based on scientific observations in order that decision-makers can assess the ability of the repository system to comply with proposed regulations.” (TSPA-SR, 2000)  The TSPA is the DOE’s attempt to link all the components of the repository system through a single performance analysis in a way provides useful information about the future safety of the repository.
  
  
• The TSPA can be conceptualized as a series of levels on a pyramid (see figure ES-1 in the TSPA-SR).  The base of the pyramid consists of the data and observations collected in the site characterization process and during the design of the engineered portions of the repository system.  This includes all the relevant features, events and processes contained in the repository system.  Conceptual and process models are constructed from the available data.  These models are qualitative hypotheses about the way that different parts of the system work and multiple conceptual models may reasonably describe the available data.  Once a set of conceptual models have been specified, they are generalized, abstracted, and compacted into a form that is usable in a computer model.  For example, a conceptual model of radionuclide transport through a rock matrix that involves a description of the behavior of individual particles within the matrix must be formulated mathematically so that it captures the salient features of the model on a level sufficiently general and abstract for incorporation into a computer model.  In the case of the DOE’s TSPA, the final models are probabilistic in nature, which means that the simulations are run many times with many different combinations of parameter values.  This kind of analysis is an attempt to “reflect the range of behaviors or values for the parameters that could be appropriate, knowing that perfect of complete knowledge of the system will never be available and that the system is inherently variable” (TSPA-SR, 2000).  The result of these numerous calculations is a forecast of the likelihood that the repository will comply with safety standards.
  
  
• As is the case with the TSPA, most performance assessments include two main elements:
• The primary element is an estimate of the most likely behavior of the repository system.  It is important to note that while such an analysis should represent the “normal evolution” of the repository, many conservative assumptions are made in performance assessments in order to compensate for uncertainty in the conceptualization of certain processes and an inability to defend positive performance, i.e. to be on the safe side.
• The next element is a quantification of the probability of natural events that might cause a loss of waste containment.  Such events include earthquakes, volcanism, or changing climatic conditions, which might cause early weakening or rupture of waste canisters.
• Some performance assessments, including the TSPA, include a human intrusion component.  The likelihood that human beings will inadvertently drill into a waste repository, possibly searching for groundwater, is unfeasible to determine so a separate analysis of the repository is performed to determine the effects of such an intrusion.  Purposeful intrusions into the repository are usually not considered.