Performance Objective for Tank Farm Closure Risk Assessments
To be meaningful, results from a numeric risk assessment of the consequences of an action must be compared against the standards for such an action. That is, before one disposes of waste or closes a facility with waste, one must show that the disposal or closure action protects the public health and safety and the environment. These standards are called performance objectives. Regulations requiring performing performance assessments, (whether federal ones like the Department of Energy [DOE] Order 435.1, Radioactive Waste Management and its implementing guides or Washington State ones like the regulations implementing the Washington Administrative Code [WAC] 173-340 ''Model Toxics Control Act - Cleanup''), usually require that the determination of performance objectives be one of the first steps performed. These performance objectives not only set comparison level for the numeric results, but also define the media, pathways, exposure scenarios (receptors), spatial locations, and times that the performance assessment must consider. Thus, a performance objective consists of a compliance level, place(s) of compliance, and time(s) of compliance. Performance objectives are not the levels that a regulatory agency will enforce in a permit or authorization. Those levels, often called enforcement levels, will be set in the permit or authorization. Rather, performance objectives are those levels against which the results of the numeric simulation will be compared to judge the success of the proposed cleanup or disposal actions. Additional comparison levels may be requested for information purposes, but are not officially part of the decision on the adequacy of the proposed action. To emphasize that the performance objectives discussed in this document are not regulatory performance objectives, the three components of the performance objective will be renamed in this document as assessment standard, point(s) of assessment, and time(s) of assessment. However, whenever quotations are taken from other documents (e.g., regulations) the quotation will not be changed from the more standard terminology. According to the Hanford Federal Facility Agreement and Consent Order (HFACCO 1989), a number of risk assessments will be required to analyze the environmental and human health impacts from retrieval and closure activities. This document is based on the Performance Objectives for the 2005 Immobilized Low-Activity Waste Performance Assessment (ILAW PA) (Mann 2002). The performance objectives in this document will be used in future risk assessments for tank waste retrieval or tank closure activities. These risk assessments are described in the Contents of Risk Assessments to Support the Retrieval and Closure of Tanks for the Washington State Department of Ecology (Mann et al. 2003) and summarized in Table 1.1. Requirements for ecological assessments are not yet presented in this document. As the requirements for such assessments are defined, this document will be revised to include the appropriate performance objectives.
- Research Organization:
- CH2M Hill Hanford Group, Inc., Richland, WA (United States)
- Sponsoring Organization:
- ENVIRONMENTAL MANAGEMENT (US)
- DOE Contract Number:
- AC27-99RL14047
- OSTI ID:
- 810632
- Report Number(s):
- RPP-14283, Rev.0; EDT-14283; TRN: US0302842
- Resource Relation:
- Other Information: PBD: 1 Mar 2003
- Country of Publication:
- United States
- Language:
- English
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