Assessing Exposure to the Public from Low Level Radioactive Waste(LLW) Transportation to the Nevada Test Site.

Cebe, J. J. ; Miller, J. J. ; Campbell, S. ; Shafer, D. S. ; Gillespie, D. ; Sedano, S. ; Church, B. W.

Technical Information Center Oak Ridge Tennessee

关键词: Public health;    Environmental exposure;    Low-level radioactive wastes;    Transportation of hazardous materials;    Nevada Test Site;   

RP-ID  :  DE2004825777

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The United States (U.S.) Department of Energy (DOE) Nevada Test Site (NTS) is one of two regional sites where low-level radioactive waste (LLW) from approved DOE and U.S. DOD generators across the United States is disposed. In federal fiscal year (FY) 2002, over 57,000 cubic meters of waste was transported to and disposed at the NTS. DOE and U.S. Department of Transportation (DOT) regulations ensure that radiation exposure from truck shipments to members of the public is negligible. Nevertheless, particularly in rural communities along transportation routes in Utah and Nevada, there is perceived risk from members of the public about incremental exposure from LLW trucks, especially when 'Main Street' and the LLW transportation route are the same. To better quantify the exposure to gamma radiation, a stationary monitoring array of four pressurized ion chambers (PICs) have been set up in a pullout just before LLW trucks reach the entrance to the NTS. The PICs are positioned at a distance of one meter from the sides of the truck trailer and at a height appropriate for the design of the trucks that will be used in FY2003 to haul LLW to the NTS. The use of four PICs (two on each side of the truck) is to minimize and to correct for non-uniformity where radiation levels from waste packages vary from side to side, and from front to back in the truck trailer. The PIC array is being calibrated by collecting readings from each PIC exposed to a known 137Cs source that was positioned at different locations on a flatbed stationed in the PIC array, along with taking secondary readings from other known sources. Continuous data collection using the PICs, with and without a truck in the array, is being used to develop background readings. In addition, acoustic sensors are positioned on each side of the PIC array to record when a large object (presumably a truck) enters the array. In FY2003, PIC surveys from as many incoming LLW trucks as possible will be made and survey data recorded automatically by dataloggers that will be periodically downloaded. Solar panels provide power for the batteries to run both the dataloggers and PICs. Truck drivers have been asked to park their truck within the PIC array for only the time it takes to complete an information log before moving on to one of two Radioactive Waste Management Sites (RWMS) on the NTS. On the log, the truck drivers record their shipment identification number, the time of day, where the waste originated, and information on the route they used to reach the NTS. This data will facilitate comparison of PIC readings with waste manifests and other waste disposal operations data collected at the RWMSs. Gamma radiation measurements collected from the PICs will be analyzed using standard health physics and statistical methods for comparison to DOT standards, but with the added benefit of obtaining an improved understanding of the variability of readings that can occur in the near vicinity of a LLW truck.