John Tauxe
was a contributing author to this work while a researcher at ORNL:
Performance Evaluation of the Technical Capabilities
of DOE Sites for Disposal of Mixed Low-Level Waste
DOE/ID-10521
EXECUTIVE SUMMARY
The Federal Facility Compliance Act (FFCAct) of 1992 requires the
U.S. Department of Energy
(DOE) to work with its regulators and with members of the
public to establish plans for the treatment of DOE’s mixed low-level waste (MLLW).
Along with other radioactive and hazardous waste, MLLW has been generated for
more than 50 y through DOE activities related to the production of materials for
nuclear weapons and research with nuclear materials. The DOE currently generates,
stores, or expects to generate (over the next five years) about 650,000 m³ of MLLW
at 41 sites in 20 states. Although the FFCAct does not specifically address disposal
of treated MLLW, both DOE and the States recognize that disposal issues are an
integral part of treatment discussions. The DOE, in collaboration with the States,
has responded to MLLW treatment and disposal issues in two ways:
- The DOE began developing plans (called “site treatment plans”) for assessing
both the capacity and capabilities for treating mixed waste for each facility at
which it stores or generates such wastes. Following a three-phase approach,
conceptual site treatment plans for each site were submitted to the appropriate
regulatory agencies (the relevant states and the U.S. Environmental Protection Agency)
in October 1993; draft site treatment plans were submitted in August 1994; and
proposed site treatment plans were submitted in April 1995. Implementation of these
plans was formalized through consent orders issued by the appropriate regulatory
agencies by October 1995 for most sites.
- The DOE established the FFCAct Disposal Workgroup (DWG) in June 1993 to work
with the States in defining and developing a process for evaluating disposal options
for treated MLLW. The focus of the DWG process and of discussions on disposal with
the States has been to identify, from among the sites currently storing or expected
to generate MLLW, those that are suitable for further evaluation in terms of their
disposal capabilities.
The performance evaluation (PE) discussed in this report was designed to
quantify and compare the potential technical capabilities of 15 DOE sites for MLLW
disposal to provide information to decision makers developing plans for the
configuration of sites for disposal of DOE MLLW. The principal goal of the PE was
to estimate, assuming grouted residuals that result from the treatment of MLLW,
permissible concentrations of radionuclides in waste for disposal at each site.
These “permissible waste concentrations” were based solely on long-term performance
of the disposal facility and surrounding environment and did not take into account
any policy or operational waste acceptance criteria that might have been developed
for a particular site. To provide a common frame of reference, grout was the waste
form evaluated in the PE because the majority of treated and stabilized DOE MLLW is
anticipated to have been stabilized by this method, although other waste forms may
be used.
The existing levels of contamination that may exist at the 15 sites have not
specifically been considered in this analysis. The site analyses did not consider
the effects of overlapping plumes from nearby disposal facilities or accidental releases.
These considerations will be included in a site-specific performance assessment and are
being addressed by DOE in its implementation of the
Defense Nuclear Facilities Safety Board Recommendation 94-2.
The PE used analyses that are consistent with the approach
currently used in many low-level waste (LLW) performance assessments. The objective
was to use a set of modeling assumptions of sufficient detail to capture major site-specific
characteristics and yet be general enough for consistent application at all sites.
Additionally, the analyses were designed to ensure that the sites were analyzed
consistently and that all major assumptions were clearly stated.
Details of the background and the results of the evaluations of the
capabilities of the DOE sites for disposal of treated MLLW residuals are provided in
the three volumes of this report.
reference for this document:
U.S. DOE, Performance Evaluation of the Technical Capabilities of
DOE Sites for Disposal of Mixed Low-Level Waste, Volume 1:
Executive Summary, DOE/ID-10521/1, Sandia National Laboratories,
Albuquerque, NM, March 1996