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Partial Facility Closure Plan for
B-20 Detonation Area
March 1994
Section 7
Implementation of Corrective Action
Guided by the findings of the CMS, a final closure action that will address the closure objective will be selected for implementation at the B-20 site with the approval of the EPA and the TNRCC. The corrective action implementation will focus on construction reliability, construction quality assurance (CQA) procedures, and operation and maintenance (O&M). Initial steps in the implementation will involve corrective action design, and development of implementation strategy and schedule. The corrective action will be terminated when the closure objectives are achieved.
The corrective action implementation phase will consist of the tasks listed below:
Implementation strategy including corrective action design and implementation schedule,
Corrective action construction including inspection and documentation, and
Operation and maintenance including O&M cost estimates, schedule and procedures.
The implementation strategy provides an overall management tool during the corrective action design and construction planning stage. A work plan will be prepared to present the construction design drawings and details, and to describe the methods, procedures (including CQA and recordkeeping), and schedule of activities that will be performed during the implementation of the closure action. This work plan will also include a record of assignment of responsibilities and delegation of authority for personnel and organizations involved. The design of the corrective action will be based on the need to achieve the closure objective, applicable regulations and standards, common construction materials, skills and methods, and safety issues.
Once the final design of the corrective action is approved by the agencies, a CQA plan will be developed for use during the construction. This plan wil define responsibility and authority of organizations and key personnel involved, CQA personnel qualification, CQA inspection and procedures, documentation and reporting. The construction documentation will also include work progress, any modifications to the design, problems encountered and problem resolution. The purpose of the construction documentation is to verify that the implemented solution meets the closure performance standard. Closure verification samples may be collected to confirm that the cleanup levels were achieved. At the completion of the construction phase, a final closure report will be prepared for B-20 site as described in section 8.
The corrective action may require operation and maintenance to ensure attainment of the closure performance standard. The length of O&M requirement will depend on the corrective action implemented. An O&M plan will be prepared, if necessary, for implementation at the B-20 site. The plan will describe normal O&M procedures, potential operating problems and anticipated remedies, routine monitoring and testing, and documentation and reporting. The O&M plan will be updated as appropriate during this phase. O&M will be terminated upon the attainment of the closure objective.
At present, the available data are insufficient to define the need or the nature of corrective action at the B-20 site. A range of corrective actions, including no action, may be applicable to the site as discussed in section 6. However, solely for cost estimating purposes, institutional controls and containment were chosen as the corrective action for the B-20 site. The containment technology is assumed to be a RCRA landfill cover over the entire area.
The institutional controls may consist of warning signs, site access restrictions and deed recordation. A RCRA landfill cover is assumed to consist of two feet of compacted clay, a 60-millimeter-thick flexible membrane overlying the clay, a drainage layer consisting of geonet, and a 1-foot-thick top soil layer with a vegetative cover. In addition, drainage structures may also be required to convey runoff from the site.
The corrective action described above is for cost estimating purposes only. The closure investigation and the baseline RA results will identify the objectives of corrective action. The corrective action which will achieve the closure objective will then be chosen through the CMS. The selected final corrective action may be different from the one used for cost estimating in this document. The closure cost estimate will be revised to correspond to the final corrective action selected through the baseline RA and the CMS.