Surface radiological investigations at environmental research area 11, (sup 137)Cs- and (sup 60)Co-contaminated plots at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Environmental Restoration Program.

摘要

A surface radiological investigation at the (sup 137)Cs- and (sup 6O)Co-contaminated forest area (Chestnut Ridge east and west plots) was conducted from January 1992 through August 1992. Results of the survey revealed numerous spots and small areas of surface contamination that followed the original placement of feeders used for (sup 6O)Co- and (sup 137)Cs-labeled seeds in a 1969--1970 study. Surface gamma exposure rates reached 380 (mu)R/h at the east plot and 400 (mu)R/h at the west plot, but approximately one-half and one- third, respectively, of the identified anomalies did not exceed 39 (mu)R/h. Results of soil sample analyses demonstrated that (sup 137)Cs and (sup 6O)Co were responsible for the elevated radiation levels. Radionuclides were found below the surface at soil sample locations, in some cases at depths below 18 in. The same pattern of subsurface contamination may be present at other elevated surface spots at both plots. These survey results show that current radiological conditions at the site remain an environmental problem. Recommendations for corrective actions are included.