Guidance for Conducting Risk Assessments and Related Risk ...

Streamlined risk evaluations can be used to justify a removal action and to identify current or potential
exposures that should be prevented. It is important to remember that the level of complexity of a
streamlined risk evaluation is based on the action to be undertaken and may in some cases require as
much effort as a conventional baseline risk assessment.
Risk guidance for D&D facilities was developed by DOE-ORO with the assumption that the
facilities may need to be evaluated with the same rigor as DOE-ORO hazardous waste sites. Therefore,
the guidance provides methods to estimate:
• the potential source terms associated with past and/or on-going releases from available historic,
operational, and environmental data;
• the probability and magnitude of releases due to catastrophic events (e.g., tornadoes); and
• the potential magnitude of releases due to deterioration of building materials with time.
These estimates can be used, in turn, to complete screening risk evaluations, baseline risk assessments,
and alternatives evaluations.
The screening risk evaluation guidance was designed to produce relative risk scores to support D&D
action, prioritization, and decision-making. The baseline risk assessment guidance was developed using
parts A through C of Risk Assessment Guidance for Superfund (EPA 1989, 1991a, 1991b) to provide a
consistent approach for projecting the potential for adverse effects to human health and the environment
from D&D facilities. These unique documents provide methods to estimate source terms from historical
and operational information regarding the nature and volume of materials contained within the
infrastructure (e.g., piping, insulation, drains, etc.). The D&D risk assessment guidance documents are
referenced in Table 4, and a brief abstract for each is provided in Appendix A.
Table 4. D&D risk assessment guidance documents
Baseline Risk Assessment Guidance for D&D Facilities, K/ER-153/R1, Oak Ridge National Laboratory, Oak Ridge,
Tennessee. (LMES 1995a)
D&D Alternatives Risk Assessment Guidance, Oak Ridge National Laboratory, Oak Ridge, Tennessee. DRAFT
(LMES 1996a)
D&D Screening Risk Evaluation Guidance, ES/ER/TM-165, Oak Ridge National Laboratory, Oak Ridge,
Tennessee. (LMES 1995b)
The methods outlined in the D&D guidance documents may be used to support a streamlined risk
evaluation. The D&D guidance documents provide information for data evaluation, source term
estimation, exposure assessment, catastrophic failure, and other related risk activities (i.e., prioritization,
evaluation of alternatives, etc.). This information helps ensure that risk assessments are consistent with
accepted regulatory guidelines and technically defensible. The guidance is not all encompassing,
however, as new risk assessment methods are being developed in the D&D area. The Risk Assessment
Technical Lead (RATL) for a particular project should consult with the project manager and the Risk
Advisory Board (RAB) as needed to ensure that:
• the most innovative and cost effective methods of assessment are used for D&D risk evaluations,
• the new methods are consistent with existing regulatory guidance, and
• the assessment will meet the needs and expectations of the DOE-ORO EM Program.
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