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U.S. Department of Energy
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Thermal modeling of core sampling in flammable gas waste tanks. Part 2: Rotary-mode sampling

Conference ·
OSTI ID:510326
; ;  [1];  [2]
  1. Los Alamos National Lab., NM (United States). Nuclear Systems Design and Analysis Group
  2. Westinghouse Hanford Co., Richland, WA (United States). Engineering Testing Lab.
The radioactive waste stored in underground storage tanks at Hanford site includes mixtures of sodium nitrate and sodium nitrite with organic compounds. The waste can produce undesired violent exothermic reactions when heated locally during the rotary-mode sampling. Experiments are performed varying the downward force at a maximum rotational speed of 55 rpm and minimum nitrogen purge flow of 30 scfm. The rotary drill bit teeth-face temperatures are measured. The waste is simulated with a low thermal conductivity hard material, pumice blocks. A torque meter is used to determine the energy provided to the drill string. The exhaust air-chip temperature as well as drill string and drill bit temperatures and other key operating parameters were recorded. A two-dimensional thermal model is developed. The safe operating conditions were determined for normal operating conditions. A downward force of 750 at 55 rpm and 30 scfm nitrogen purge flow was found to yield acceptable substrate temperatures. The model predicted experimental results reasonably well. Therefore, it could be used to simulate abnormal conditions to develop procedures for safe operations.
Research Organization:
Los Alamos National Lab., NM (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
510326
Report Number(s):
LA-UR--97-63; CONF-970824--9; ON: DE97003399
Country of Publication:
United States
Language:
English