Letter Report to Address Comments on the Closure Report for Corrective Action Unit 224: Decon Pad and Septic Systems, Nevada Test Site, Nevada, Revision 0, March 2008

The Closure Report (CR) for Corrective Action Unit (CAU) 224, Decon Pad and Septic Systems, was approved by the Nevada Department of Environmental Protection (NDEP) on November 01, 2007. The approval letter contained the following two comments: Comment 1--For 06-05-01, 06-17-04, 06-23-01 provide evidence that the 6 inch VCP pipe originating from building CP-2 is no longer active and sealed to prevent possible future contamination. Comment 2--For the area that includes 06-03-01, provide evidence that active lines are no longer feeding the North and South lagoons and have been sealed to prevent possible future contamination. To address these comments, closure documentation was reviewed, and site visits were conducted to locate and document the areas of concern. Additional fieldwork was conducted in March 2008 to seal the lines and openings described in the two comments. Photographs were taken of the closed drains and lines to document that the NDEP comments were adequately addressed and potential inadvertent discharge to the environment has been eliminated. Investigation and closure documentation was reviewed to identify the locations of potential drains, lines, and other features that could receive and/or transmit liquid. Based on the investigation findings and subsequent closure activities, no openings, distribution boxes, or other features (excluding known floor drains at CP-2) that could receive liquid were found at the CP-2 location (Figure 1), and potential manholes for the north and south sewage lagoons were identified for Corrective Action Site (CAS) 06-03-01 (Figure 2). The distribution box identified in Figure 1 was not located during the investigation and was assumed to have been previously removed