Corrective Action Investigation Plan for Corrective Action Unit 550: Smoky Contamination Area Nevada National Security Site, Nevada.

摘要

Corrective Action Unit (CAU) 550 is located in Areas 7, 8, and 10 of the Nevada National Security Site, which is approximately 65 miles northwest of Las Vegas, Nevada. CAU 550, Smoky Contamination Area, comprises 19 corrective action sites (CASs). Based on process knowledge of the releases associated with the nuclear tests and radiological survey information about the location and shape of the resulting contamination plumes, it was determined that some of the CAS releases are co-located and will be investigated as study groups. This document describes the planned investigation of the following CASs (by study group): (1) Study Group 1, Atmospheric Test - CAS 08-23-04, Atmospheric Test Site T-2C; (2) Study Group 2, Safety Experiments - CAS 08-23-03, Atmospheric Test Site T-8B - CAS 08-23-06, Atmospheric Test Site T-8A - CAS 08-23-07, Atmospheric Test Site T-8C; (3) Study Group 3, Washes - Potential stormwater migration of contaminants from CASs; (4) Study Group 4, Debris - CAS 08-01-01, Storage Tank - CAS 08-22-05, Drum - CAS 08-22-07, Drum - CAS 08-22-08, Drums (3) - CAS 08-22-09, Drum - CAS 08-24-03, Battery - CAS 08-24-04, Battery - CAS 08-24-07, Batteries (3) - CAS 08-24-08, Batteries (3) - CAS 08-26-01, Lead Bricks (200) - CAS 10-22-17, Buckets (3) - CAS 10-22-18, Gas Block/Drum - CAS 10-22-19, Drum; Stains - CAS 10-22-20, Drum - CAS 10-24-10, Battery. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each study group. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on January 31, 2012, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 550. The potential contamination sources associated with the study groups are from nuclear testing activities conducted at CAU 550. The DQO process resulted in an assumption that the total effective dose (TED) within the default contamination boundary of CAU 550 exceeds the final action level and requires corrective action. The presence and nature of contamination outside the default contamination boundary at CAU 550 will be evaluated based on information collected from a field investigation. Radiological contamination will be evaluated based on a comparison of the TED at sample locations to the dose-based final action level. The TED will be calculated as the total of separate estimates of internal and external dose. Results from the analysis of soil samples will be used to calculate internal radiological dose. Thermoluminescent dosimeters placed at the center of each sample location will be used to measure external radiological dose. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each group of CASs.