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Title: Radiological and Environmental Monitoring at the Clean Slate I and III Sites, Tonopah Test Range, Nevada, With Emphasis on the Implications for Off-site Transport

In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]) implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range [NAFR]). Operation Roller Coaster consisted of four tests in which chemical explosions were detonated in the presence of nuclear devices to assess the dispersal of radionuclides and evaluate the effectiveness of storage structures to contain the ejected radionuclides. These tests resulted in the dispersal of plutonium over the ground surface downwind of the test ground zero (GZ). Three tests—Clean Slate I, II, and III—were conducted on the TTR in Cactus Flat. The fourth, Double Tracks, was conducted in Stonewall Flat on the NTTR. The Desert Research Institute (DRI) installed two monitoring stations in 2008, Station 400 at the Sandia National Laboratories (SNL) Range Operations Center (ROC) and Station 401 at Clean Slate III. Station 402 was installed at Clean Slate I in 2011 to measure radiological, meteorological, and dust conditions. The monitoring activity was implemented to determine if radionuclide contamination in the soil at the Clean Slate sites was being transported beyond the contamination area boundaries. Some ofmore » the data collected also permits comparison of radiological exposure at the TTR monitoring stations to conditions observed at Community Environmental Monitoring Program (CEMP) stations around the NTTR. Annual average gross alpha values from the TTR monitoring stations are higher than values from the surrounding CEMP stations. Annual average gross beta values from the TTR monitoring stations are generally lower than values observed for the surrounding CEMP stations. This may be due to use of sample filters with larger pore space because when glass-fiber filters began to be used at TTR Station 400, gross beta values increased. Gamma spectroscopy typically identified only naturally occurring radionuclides. The radionuclides cesium-134 and -137 were identified in only two samples at each station collected in the weeks following the destruction of the nuclear power reactor in Fukushima, Japan, on March 11, 2011. Observed gamma energy values never exceeded the local background by more than 4 μR/h. The higher observed gamma values were coincident with wind from any of the cardinal directions, which suggests that there is no significant transport from the Clean Slate contamination areas. Annual average daily gamma values at the TTR stations are higher than at the surrounding CEMP stations, but they are equivalent to or just slightly higher than the background estimates made at locations at equivalent elevations, such as Denver, Colorado. Winds in excess of approximately 15 mph begin to resuspend soil particles and create dust, but dust generation is also affected by soil temperature, relative humidity, and soil water content. Power curves provide good predictive equations for dust concentration as a function of wind speed. However, winds in the highest wind speed category occur infrequently. iii« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Desert Research Inst. (DRI), Las Vegas, NV (United States)
Publication Date:
OSTI Identifier:
1182262
Report Number(s):
45257
DOE/NV/0000939-19
DOE Contract Number:
NA0000939
Resource Type:
Technical Report
Research Org:
Desert Research Inst. (DRI), Las Vegas, NV (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]) implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range [NAFR]). Operation Roller Coaster consisted of four tests in which chemical explosions were detonated in the presence of nuclear devices to assess the dispersal of radionuclides and evaluate the effectiveness of storage structures to contain the ejected radionuclides. These tests resulted in the dispersal of plutonium over the ground surface downwind of the test ground zero (GZ). Three tests—Clean Slate I, II, and III—were conducted on the TTR in Cactus Flat. The fourth, Double Tracks, was conducted in Stonewall Flat on the NTTR.