EXECUTIVE SUMMARY

Site Characterization Meets Key Milestone;
Waste Acceptance Issues Remain Open

Overview

During Fiscal Year 2000, the Office of Civilian Radioactive Waste Management (OCRWM) continued to make significant progress toward completing the characterization of the Yucca Mountain, Nevada, candidate repository site and preparing for a future national decision on whether to go forward with developing a repository. The majority of the Program's funding and work effort were centered on the science and engineering activities that would most effectively quantify the level of uncertainty in analyses of repository performance. OCRWM's appropriation for Fiscal Year 2000 was $51.5 million lower than requested, contributing to a shortfall of roughly $110 million over the past three years. Nevertheless, the Program met all three performance targets in the Secretary's Fiscal Year 2000 performance agreement with the President and completed important work in many other areas, even though some important engineering and design activities were deferred.

Performance Target #1: Complete public hearings on draft environmental impact statement Following the issuance of the Draft Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada (draft EIS), in July 1999, the Program conducted a 199-day public comment period and held 21 public hearings. The hearings and public comment period complied with the process mandated in the National Environmental Policy Act.

Draft EIS meeting in Las Vegas, Nevada

Performance Target #2: Select the reference design for site recommendation and license application
Following an evaluation of design options, the Program developed a reference design and a set of operating modes to support a preliminary site suitability evaluation for a potential site recommendation. The reference design could be used as the basis for statutorily required hearings on a potential site recommendation and reflects comments from stakeholders, including oversight organizations.

A preliminary design for license application will evolve and may include adjustments to increase public health and safety and to reduce cost without affecting safety. Final license application design selection will be based on the Environmental Protection Agency's (EPA) final radiation protection standard for an underground repository at Yucca Mountain and the Nuclear Regulatory Commission's (NRC) final licensing criteria for a potential Yucca Mountain repository, which will implement the EPA standard.

Performance Target #3: Select the reference natural systems models for site recommendation and license application
The Program selected process models of the natural systems, verified data and validated model codes, and developed abstractions of the models for use in a total system performance assessment for a potential repository at Yucca Mountain. The reference natural systems models selected in Fiscal Year 2000 provide the scientific basis and foundation for a potential site recommendation.

The process models were based on the most recently available scientific information and will be updated through an iterative process to support a possible license application. Work continued to confirm the models under a range of environmental conditions and to reduce uncertainties in long-term performance assessments. Site investigations conducted in Fiscal Year 2000 assisted us in developing a more complete three-dimensional model of the geologic setting for the potential repository.

Yucca Mountain Site Characterization Project

Fiscal Year 2000 work performed by the Yucca Mountain Site Characterization Project supported the achievement of the three goals in the Secretary's Performance Agreement with the President by providing the technical information necessary to select and evaluate reference designs and natural systems models for a potential site recommendation. Project personnel also coordinated and staffed the public hearings on the draft environmental impact statement and subsequently cataloged the comments received during the public comment period to facilitate developing responses.

Conducting hearings on the draft environmental impact statement
The draft EIS provides the background, data, and analyses that can help government officials and the public understand the potential environmental impacts of the proposed action: constructing, operating and monitoring, and eventually closing a repository at Yucca Mountain. It also examines the impacts of transporting waste from around the country to the repository. The Program's preferred alternative is to proceed with repository development, because the analysis did not identify any potentially significant environmental impacts that would be a basis for not proceeding with the proposed action. To provide a basis for comparison with the proposed action, the draft EIS also presents a "no-action" alternative.

Twenty-one public hearings were held, 10 in Nevada and 11 in other States. Approximately 2,600 individuals attended the public hearings and over 700 provided comments. At the close of the 199-day public comment period, we had received over 11,000 comments.

Selecting a reference design and reference natural systems models
Selecting a reference design and reference natural systems models is essential to demonstrating repository performance. Our scientific data collection and experimentation continued to focus on quantifying, and thereby reducing, uncertainty about the behavior of the natural environment and about how a repository would perform in that environment. As our models are refined to better represent the behavior of both engineered and natural systems, we will develop an improved understanding of how a Yucca Mountain repository can be expected to perform.

The Viability Assessment of a Repository at Yucca Mountain, released in December 1998, identified key areas where additional work was needed to reduce uncertainty. Activities in the areas of gathering additional scientific data and updating models based on those data, improving engineering design, and finalizing the regulatory framework all helped to support achievement of our Fiscal Year 2000 performance goals and development of a potential site recommendation.

Gathering additional scientific data and updating models
Most scientific studies are carried out at facilities on the site, augmented by off-site laboratory and field studies. The centerpiece of our study facilities is the underground Exploratory Studies Facility, the main loop of which is nearly 8 kilometers (5 miles) long. Transecting it is the cross-drift, a tunnel 2.8 kilometers (1.67 miles) long, that provides direct access to the central and western portions of the proposed repository block. Alcoves and niches within these facilities are instrumented for testing. Other facilities include more than 350 boreholes drilled from within underground facilities; more than 450 boreholes drilled from the surface; the Busted Butte Test Facility, which gives us access to rock similar to that beneath the potential repository horizon; over 200 pits and trenches; monitoring wells; and Global Positioning System stations. These locations yielded data on geologic, geochemical, geomechanical, and hydrologic features and processes, and the coupled mechanical, hydrologic, and chemical effects of heat on rock.

We are most interested in two areas: movement of water and the effect of heat on the host rock. These areas, which have been studied since the beginning of site investigations at Yucca Mountain, were identified once again in the viability assessment and raised as concerns by the Nuclear Waste Technical Review Board.

Hydrology experiment in enhanced chacterization of repository block (cross-drift)

Water seeping from the surface down approximately 300 meters (1,000 feet) into the repository emplacement tunnels is expected to be the primary source of any future waste package corrosion. We are studying water movement through three zones: unsaturated rock from the surface to the proposed repository site; unsaturated rock from the repository to the water table; and, finally, the saturated rock below the water table. We continued to investigate under what conditions, in what quantities, and at what rates water could seep onto waste packages. Studies of seepage and water flow helped us learn how water infiltrates the rock of the unsaturated zone. To further such studies, we began to construct facilities within the cross-drift, directly within the rock areas that would host a repository. Seepage tests were also performed within the main tunnel of the cross-drift. We will use the resulting data to verify and increase confidence in models of water flow from the surface to the repository and seepage of water into drifts. Results to date indicate that water does not flow uniformly through the rock and that, under current climatic conditions, very little water flows through the repository horizon.

The test facility at Busted Butte provided scientists the ability to study how water travels through rock very similar to that beneath the potential repository horizon. Sorption measurements at Busted Butte using surrogate radionuclides confirmed that transport data from laboratory tests are applicable to site-scale modeling.

Once radionuclide-bearing water reaches the water table, it can flow horizontally and could eventually reach the accessible environment. To understand how groundwater flows in the fractured aquifer below the repository and what the radionuclide sorption properties of the aquifer are, we monitored boreholes and conducted tracer testing at the C-Well complex. Wells drilled by Nye County, Nevada, also yielded valuable data on the saturated zone. Laboratory tests helped us better understand the radionuclide-sorption properties of the alluvium and volcanic aquifers. We used the data to refine our estimates of groundwater flow properties and to better understand how sorption of radionuclides could reduce radionuclide concentrations in groundwater.

To more closely calibrate a regional hydrologic model to observations of actual conditions at the Yucca Mountain site, we continued our five-year collaboration with the U.S. Geological Survey; the U.S. Fish and Wildlife Service; the National Park Service; representatives from Nye County, Nevada, and Inyo County, California; and the Nevada State Engineer's Office. Fiscal Year 2000 tasks included field work to gather new data and refinement of the regional hydrologic model. We also incorporated new data into our three-dimensional geologic model of the site.

Busted Butte unsaturated zone transport test

Heat generated by radioactive decay of the waste could alter the surrounding rock and affect the rate at which waste packages degrade and radionuclides are released. Three field heater tests and additional laboratory tests continued to generate valuable data. Results thus far include identification of conduction as the dominant heat transfer mechanism and the preliminary indication that rock pore water mobilized by heat tends to drain by gravity to below the heated region, rather than staying perched above it. Improving engineering design In Fiscal Year 2000, OCRWM evaluated the enhanced design alternative selected in Fiscal Year 1999 as the reference design for a potential site recommendation. We evaluated a range of thermal loading options for a potential site recommendation design that uses more intensive thermal management techniques than the viability assessment reference design. These techniques include thermal blending of fuel assemblies, closer spacing of the waste packages with wider spacing of the emplacement drifts, and ventilation.

We adopted changes that include adding drip shields to help keep water from waste packages and using more corrosion-resistant materials in the waste packages. In Fiscal Year 2000, a subset of the waste package designs was evaluated to support a potential site recommendation. Through a sensitivity analysis, we determined which waste package designs best represent the widest array of design configurations and waste forms. The analysis also determined which design criteria would be evaluated and by which representative design. The analysis resulted in the identification of four waste package designs as adequate to demonstrate likely compliance with anticipated regulatory requirements. The design analysis illustrated that the identified waste package designs performed their containment functions for anticipated design basis events.


Waste package design

Another important task that will support a possible site recommendation was the completion of system description documents for major repository subsystems related to safety, such as the materials handling system. These documents specify requirements for a repository subsystem and describe the resulting design. The entire suite of documents will constitute life-cycle records of potential repository development and will be retained as permanent records.

Moving toward a final regulatory framework
In Fiscal Year 2000, the regulatory framework for evaluating the suitability of the Yucca Mountain site moved closer to final form. At the beginning of the fiscal year, the Department of Energy (DOE) published a proposed revision to its repository siting guidelines. After a public comment period, we provided the draft notice of final rulemaking to NRC in May 2000 for concurrence. The proposed revised guidelines reflect a shift away from a generic approach that could apply to any site and that focused on individual technical criteria to a site-specific approach that relies on an overall evaluation of the expected performance of a potential repository at Yucca Mountain. This approach is consistent with NRC's proposed repository licensing criteria released in 1999. DOE's proposed siting guidelines will result in an assessment of the site's likely ability to meet EPA's radiation protection standards, as implemented by NRC.

EPA published proposed radiation protection standards for a potential repository at Yucca Mountain in August 1999, and in June 2001 issued the final standards. NRC must conform, as necessary, its licensing criteria to be consistent with EPA's standards.

Waste Acceptance, Storage, and Transportation Project
In response to funding constraints, we were forced to defer most of the planning activities related to waste acceptance, storage, and transportation. Nonetheless, with funding for this Project at less than one percent of our Fiscal Year 2000 budget, we completed several important tasks related to spent nuclear fuel acceptance.

We continued to manage the contracts we executed with utilities under the Nuclear Waste Policy Act and to gather the data about their spent fuel inventories that are required for waste acceptance. Under these contracts, DOE was to start accepting spent nuclear fuel from utilities in 1998. With no Federal facility available to receive the material, utilities pursued litigation to seek relief from hardships they allege as a consequence of DOE's delay in accepting waste.

On July 20, 2000, DOE reached its first agreement with a utility on spent fuel acceptance. The agreement with the PECO Energy Company settles potential litigation over spent fuel storage costs that PECO has incurred due to DOE's delay in commencing spent fuel acceptance. This agreement demonstrates that DOE and the utilities can reach a resolution regarding DOE's delay without resorting to costly and protracted litigation. Some utilities are running out of "wet storage" - engineered pools of water where spent nuclear fuel assemblies are stored pending acceptance by DOE. As an alternative to wet storage, a successful demonstration of a prototype for a dry transfer system for spent nuclear fuel was conducted in October 1999. Congress has directed DOE to develop this system cooperatively with the nuclear utility industry. NRC completed its assessment of our Topical Safety Analysis Report for the dry transfer system and issued a draft Safety Assessment Evaluation Report. We provided comments and are awaiting release of the final report.

Wet and dry storage

Program Management Center

Quality assurance
Quality assurance is a critical component of our work process to ensure our products protect the public's health and safety and withstand scrutiny if the site recommendation and license application stages begin. Through audits, surveillance, and assessments, our Office of Quality Assurance continued to work closely with technical personnel conducting scientific studies, design work, and performance assessment to identify activities with the greatest impact on levels of confidence related to evaluations of site suitability.

In Fiscal Year 2000, quality assurance personnel conducted audits to examine whether OCRWM activities were performed under appropriate quality assurance requirements, whether requirements were fully understood and properly implemented, and whether compliance was adequately documented. With regard to performance assessment, quality assurance reviews focused on model validation, qualification of existing data, and software control. Close interactions between quality assurance and technical personnel yielded real-time feedback on the quality assurance program and specific quality assurance activities. As a result, the quality assurance staff was able to assist in streamlining and improving requirements in several key areas, including scientific model validation, data qualification, and software control. These improvements were incorporated into the OCRWM Quality Assurance Requirements and Description, Revision 10, released in April 2000.

Program management and integration
On March 13, 2000, OCRWM released Revision 3 of the Civilian Radioactive Waste Management Program Plan, which provides a summary of the Program's statutory mission, vision, and strategic objectives, and establishes performance goals and strategies for their achievement. The plan also details the Program's milestones, major activities over the next five years, and projected funding requirements. This revision of the plan reflects programmatic changes made since the publication of the viability assessment and the Program's updated regulatory framework. It also reflects the impact on plans and schedules that lower-than-requested appropriation levels had on the Program.

Consistent with DOE-wide efforts to improve project management, we strengthened the planning and control that will ensure that the components of a waste management system are integrated, safe, reliable, and cost-effective. In our efforts to define how the Civilian Radioactive Waste Management Program is managed, we issued the Major System Management Policy, Revision 1, in August 2000. This document implements statutory, regulatory, and DOE requirements for an integrated program/project management system, states minimum requirements, and establishes a performance-based management approach.

Also prepared was an update of the 1998 total system life-cycle cost estimate, which had supported the 1998 viability assessment. The updated estimate reflects an evaluation of the current reference repository design.

The cost estimate is the basis for OCRWM's annual review to determine whether the fees charged to the owners and generators of spent nuclear fuel remain adequate to cover the costs of disposal of that material. In Fiscal Year 2000, we prepared an updated fee adequacy assessment report. Both documents were released in May 2001.

Maintaining the integrity of the information generated by years of site investigations, engineering, and performance assessment and making it readily accessible remained a top priority. A principal driver behind our application of information technology is the need to access information during a potential licensing proceeding. We continued to develop an Internet-based Licensing Support Network, in compliance with requirements defined by the NRC.

In Fiscal Year 2000, OCRWM fulfilled an important DOE goal by implementing the Secretarial initiative for an integrated safety management system to ensure that all management and work practices employ appropriate safety standards for protecting workers, the public, and the environment. An independent team of safety experts within DOE conducted the verification, and they concluded that a successful integrated safety management system had been established. We declared the full implementation of an integrated safety management system on September 29, 2000.

External interactions
In Fiscal Year 2000, OCRWM's Director and staff at Headquarters and at the Yucca Mountain Site Characterization Office met with representatives of over 20 Federal agencies, environmental groups, technical and professional organizations, policy groups, and international organizations. Such meetings enable us to better understand our external counterparts and address their concerns, as appropriate, by providing information about the Program to them.

An important step toward international information exchange and consensus building occurred with DOE's sponsorship of an international conference on geologic repositories. Participants issued a joint declaration that reiterated the international commitment to safe management of nuclear waste.

OCRWM continued to work directly with the Russian Federation to support the Nation's nonproliferation objectives. In Fiscal Year 2000, we concluded a memorandum of agreement to assist the Russian Federation in developing a path forward for radioactive waste and surplus fissile materials disposition. OCRWM continued to participate in a working group on spent fuel issues with officials of the Russian Federation's Ministry for Atomic Energy (Minatom). Other meetings with Minatom focused on expanding overall scientific and technological cooperation, sharing repository research and design information, and identifying other opportunities to develop cooperative activities.


Science is a continuous process

OCRWM also continued its cooperative relationship with the Organization for Economic Cooperation and Development/Nuclear Energy Agency, the International Atomic Energy Agency, and the International Association for the Environmentally Safe Disposal of Radioactive Materials.

Conclusion

In Fiscal Year 2000, OCRWM met the performance targets identified in the Secretary's Performance Agreement with the President. Completing the public hearing process on the draft environmental impact statement, developing a reference design, and selecting reference natural systems models provided the foundation for possible development of a site recommendation.

As the fiscal year closed, we were focused on completing and documenting the scientific and technical work needed to support a determination by the Secretary on whether to recommend Yucca Mountain for development as a repository. Although we view this science-based approach as a process that would continue to the point of repository closure far in the future, the submittal of a site recommendation would mark the end of the site characterization phase of our work. This phase, in which the Nation has invested approximately $4 billion and nearly two decades of effort, has produced an extensive understanding of the Yucca Mountain site and of what is required to design a repository that would perform safely in that setting for many thousands of years.

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