Nevada National Security Site 2010 Waste Management Monitoring Report Area 3 and Area 5 Radioactive Waste Management Sites

National Security Technologies, LLC

National Security Technologies, LLC

关键词: Radiation Monitoring;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Radiations;    Waste Management, Nnss, Area 3 And Area 5, Rwms, Radioactive Waste Management Sites;    Precipitation;   

DOI  :  10.2172/1041413
RP-ID  :  DOE/NV/25946--1226
RP-ID  :  DE-AC52-06NA25946
RP-ID  :  1041413

美国|英语

来源: UNT Digital Library

【 摘 要 】

Environmental monitoring data were collected at and around the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) at the Nevada National Security Site (NNSS). These data are associated with radiation exposure, air, groundwater, meteorology, vadose zone, subsidence, and biota. This report summarizes the 2010 environmental data to provide an overall evaluation of RWMS performance and to support environmental compliance and performance assessment (PA) activities. Some of these data (e.g., radiation exposure, air, and groundwater) are presented in other reports (National Security Technologies, LLC, 2010a; 2010b; 2011). Direct radiation monitoring data indicate exposure levels at the RWMSs are within the range of background levels measured at the NNSS. Air monitoring data at the Area 3 and Area 5 RWMSs indicate that tritium concentrations are slightly above background levels. All gamma spectroscopy results for air particulates collected at the Area 3 and Area 5 RWMS were below the minimum detectable concentrations, and concentrations of americium and plutonium are only slightly above detection limits. The measured levels of radionuclides in air particulates and moisture are below derived concentration guides for these radionuclides. Groundwater monitoring data indicate that the groundwater in the uppermost aquifer beneath the Area 5 RWMS is not impacted by facility operations. The 246.9 millimeters (mm) (9.72 inches [in.]) of precipitation at the Area 3 RWMS during 2010 is 56 percent above the average of 158.7 mm (6.25 in.), and the 190.4 mm (7.50 in.) of precipitation at the Area 5 RWMS during 2010 is 50 percent above the average of 126.7 mm (4.99 in.). Soil-gas tritium monitoring at borehole GCD-05 continues to show slow subsurface migration consistent with previous results. Water balance measurements indicate that evapotranspiration from the vegetated weighing lysimeter dries the soil and prevents downward percolation of precipitation more effectively than evaporation from the bare-soil weighing lysimeter. Data from the automated vadose zone monitoring system for the operational waste pit covers show that moisture from precipitation did not percolate below 90 centimeters (cm) (3 feet [ft]) before being removed by evaporation. Moisture from precipitation did not percolate below 61 cm (2 ft) in the vegetated final mono-layer cover on the U-3ax/bl disposal unit at the Area 3 RWMS before being removed by evapotranspiration. During 2010, there was no drainage through 2.4 meters (8 ft) of soil from the Area 3 drainage lysimeters that received only natural precipitation. Water drained from both the bare-soil drainage lysimeter and the invader species drainage lysimeter that received 3 times natural precipitation. All 2010 monitoring data indicate that the Area 3 and Area 5 RWMSs are performing within expectations of the model and parameter assumptions for the facility PAs.