Central Plateau Completion Strategy

Similar to the approach in the 100 Areas, where actions were taken to complete each individual reactor area, each of the parcels selected for early action in the Central Plateau require a group of actions to move to long-term stewardship. Unlike the 100 Areas where the cleanup goals established were predicated on unrestricted future use, the 200 Area cleanup goals would be based on restricted future use, appropriate institutional controls, and effective containment actions to protect human health and the environment. Remedies for the high-risk sites as well as all of the other waste sites located within boundaries of the U Plant Area, the BC cribs and trenches, the Plutonium Finishing Plant cribs, and the PUREX cribs would be based on interim action records of decision.

The closure schedule for the U Plant Area provides an example of the actions needed to proceed through the investigation phase to remedial actions and other measures required to transition to long-term stewardship and to limit the impact of future releases to the 200-UP-1 Operable Unit.

The strategy to complete cleanup of the Central Plateau and transition to long-term stewardship focuses on completing actions on land within the Core Zone that contains high-risk waste sites with significant potential to contaminate groundwater and to remediate those lower risk sites that are located outside the Core Zone of the Central Plateau (i.e., shrinking the contaminated footprint). The four parcels selected as high-risk sites and slated for completion by 2011 do not include tank farms and those high-risk sites immediately adjacent to tank farms. Schedules for completion of those high-risk sites and the adjacent tank farms depend on the timing and strategy for closure of the tank farms.

The area closure approach relies on coordinated actions to eliminate septic system discharges, refurbish and relocate water lines, and abandon high-risk wells within the area adjacent to high-risk sites that represent a long-term risk to the 200-UP-1 Operable Unit. Once these actions are complete, remedial actions on the high-risk sites would be implemented and an upgraded monitoring network would be put in place to meet the requirements for long-term stewardship.

Detailed schedules of activities to support each of the other high-risk sites are currently under development. These activities also will be closely coordinated with the decontamination and decommissioning of facilities within the Central Plateau.

For the areas outside the Core Zone described in the Shrinking the Contaminated Footprint section of this website, a much more limited group of actions is envisioned than for areas with high-risk sites. The two parcels addressed in this section contain all of the 200 Area waste sites outside the Core Zone. The 200 North Gable/B Pond complex and the Central Landfill parcels represent only marginal risk to groundwater. However, early action in these areas is expected to preserve the existing groundwater quality and support a final remedy of monitored natural attenuation for much of the 200-PO-1 and 200-BP-5 Operable Units. These parcels also require decommissioning of certain high-risk wells, but no septic systems or waterlines are located in these parcels. Development of institutional controls for these areas are less dependent on the residual contamination left after the remedial action is complete than on the need for restricted access to assure the public is protected from potential air releases from operating facilities.

Once source control actions are complete, the groundwater monitoring networks for these parcels will be upgraded and a long-term operations and maintenance plan for groundwater and environmental monitoring will be completed.

The long-range plan for continued operation of the 200 Area, coupled with the existing inventory of hazardous and radioactive contamination, make it unlikely that the Core Zone of the Central Plateau will be deleted from the National Priorities List. Efforts to pursue partial deletion of lands outside the Core Zone may be possible, but must be made in the context of continuing operations.