摘要: |
The U.S. Department of Energy (DOE) Office of Environmental Management (EM) cleanup mission at Oak Ridge National Laboratory (ORNL) includes dispositioning facilities, contaminated legacy materials/waste, and contamination sources and remediation of soil under facilities, groundwater, and surface water to support final Records of Decision (RODs). The Integrated Facilities Disposition Project (IFDP) is a roughly $15B project for completion of the EM mission at Oak Ridge, with a project duration of up to 35 years. The IFDP Mission Need Statement - Critical Decision-0 (CD-0) - was approved by DOE in July 2007, and the IFDP Alternative Selection and Cost Range - Critical Decision-1 (CD-1) - was approved in November 2008. The IFDP scope includes reconfiguration of waste collection and treatment systems as needed to complete the IFDP remediation and decontamination and decommissioning (D&D) missions in a safe and cost-effective manner while maintaining compliance with all governing regulations and bodies and preserving the support of continuing operations at ORNL. A step in the CD-1 approval process included an external technical review (ETR) of technical approaches proposed in the CD-1 document related to the facility reconfiguration for the ORNL radioactive waste and liquid low-level waste management systems. The ETR team recommended that the IFDP team consider the use of trenchless technologies for installing pipelines underground in and around contaminated sites as part of the alternatives evaluations required in support of the CD-2 process. The team specifically recommended evaluating trenchless technologies for installing new pipes in existing underground pipelines as an alternative to conventional open trench installation methods. Potential benefits could include reduction in project costs, less costly underground piping, fewer disruptions of ongoing and surface activities, and lower risk for workers. While trenchless technologies have been used extensively in the sanitary sewer and natural gas pipeline industries, they have been used far less in contaminated environments. Although trenchless technologies have been used at ORNL in limited applications to install new potable water and gas lines, the technologies have not been used in radioactive applications. This study evaluates the technical risks, benefits, and economics for installing gravity drained and pressurized piping using trenchless technologies compared to conventional installation methods for radioactive applications under ORNL geological conditions. A range of trenchless installation technologies was reviewed for this report for general applicability for replacing existing contaminated piping and/or installing new pipelines in potentially contaminated areas. Installation methods that were determined to have potential for use in typical ORNL contaminated environments were then evaluated in more detail for three specific ORNL applications. Each feasible alternative was evaluated against the baseline conventional open trench installation method using weighted criteria in the areas of environment, safety, and health (ES&H); project cost and schedule; and technical operability. The formulation of alternatives for evaluation, the development of selection criteria, and the scoring of alternatives were performed by ORNL staff with input from vendors and consultants. A description of the evaluation methodology and the evaluation results are documented in the following sections of this report. |