Corrective Action Investigation Plan for Corrective Action Unit 204: Storage Bunkers, Nevada Test Site, Nevada (December 2002, Revision No.: 0), Including Record of Technical Change No. 1

The Corrective Action Investigation Plan contains the U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 204 under the Federal Facility Agreement and Consent Order. Corrective Action Unit 204 is located on the Nevada Test Site approximately 65 miles northwest of Las Vegas, Nevada. This CAU is comprised of six Corrective Action Sites (CASs) which include: 01-34-01, Underground Instrument House Bunker; 02-34-01, Instrument Bunker; 03-34-01, Underground Bunker; 05-18-02, Chemical Explosives Storage; 05-33-01, Kay Blockhouse; 05-99-02, Explosive Storage Bunker. Based on site history, process knowledge, and previous field efforts, contaminants of potential concern for Corrective Action Unit 204 collectively include radionuclides, beryllium, high explosives, lead, polychlorinated biphenyls, total petroleum hydrocarbons, silver, warfarin, and zinc phosphide. The primary question for the investigation is: ''Are existing data sufficient to evaluate appropriate corrective actions?'' To address this question, resolution of two decision statements is required. Decision I is to ''Define the nature of contamination'' by identifying any contamination above preliminary action levels (PALs); Decision II is to ''Determine the extent of contamination identified above PALs. If PALs are not exceeded, the investigation is completed. If PALs are exceeded, then Decision II must be resolved. In addition, data will be obtained to support waste management decisions. Field activities will include radiological land area surveys, geophysical surveys to identify any subsurface metallic and nonmetallic debris, field screening for applicable contaminants of potential concern, collection and analysis of surface and subsurface soil samples from biased locations, and step-out sampling to define the extent of contamination, as necessary. The results of this field investigation will support a defensible evaluation of corrective action alternatives in the corrective action decision document