Nevada Test Site 2009 Waste Management Monitoring Report Area 3 and Area 5 Radioactive Waste Management Sites

Waste, NSTec Radioactive

National Security Technologies, LLC (United States)

关键词: Air Quality;    Meteorology Waste Management, Area 3, Area 5, Nevada Test Site, Radioactive Waste;    Radioactive Waste Facilities;    Tritium;    Environmental Quality;   

DOI  :  10.2172/992507
RP-ID  :  DOE/NV/25946--1009
RP-ID  :  DE-AC52-06NA25946
RP-ID  :  992507

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 Test Site (NTS). These data are associated with radiation exposure, air, groundwater, meteorology, vadose zone, subsidence, and biota. This report summarizes the 2009 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.Direct radiation monitoring data indicate exposure levels at the RWMSs are within the range of background levels measured at the NTS. Air monitoring data at the Area 3 and Area 5 RWMSs indicate that tritium concentrations are slightly above background levels. All gammaspectroscopy 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. Radon flux from waste covers is well below regulatory limits. Groundwater monitoring data indicate that the groundwater in the uppermost aquifer beneath the Area 5 RWMS is not impacted by facility operations. The 87.6 millimeters (mm) (3.45 inches [in.]) of precipitation at the Area 3 RWMS during 2009 is 43 percent below the average of 152.4 mm (6.00 in.), and the 62.7 mm (2.47 in.) of precipitation at the Area 5 RWMS during 2009 is 49 percent below the average of 122.5 mm (4.82 in.). Soil-gas tritium monitoring at borehole GCD-05 continues to show slow subsurfacemigration 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 weighinglysimeter. 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 30 cm (1 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 2009, there was no drainage through 2.4 meters (8 ft) of soil from the Area 3 drainage lysimeters that received only natural precipitation or were vegetated, but water drained from the bare-soil Area 3 drainage lysimeter that received 3 times natural precipitation. Elevated tritium levels in plants and animals sampled from the Area 3 and Area 5 RWMSs show tritium uptake by the biota, but the low levels of other radionuclides do not indicate that there has been biota intrusion into the waste.All 2009 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.