Atmospheric pressure fluctuations and oxygen enrichment in waste tanks
During In-Tank Precipitation (ITP) processing radiolytic decomposition of tetraphenylborate and water can produce benzene and hydrogen, which, given sufficiently high oxygen concentrations, can deflagrate. To prevent accumulations of benzene and hydrogen and avoid deflagration, continuous nitrogen purging is maintained. If the nitrogen purging is interrupted by, for example, a power failure, outside air will begin to seep into the tank through vent holes and cracks. Eventually a flammable mixture of benzene, hydrogen, and oxygen will occur (deflagration). However, this process is slow under steady-state conditions (constant pressure) and mechanisms to increase the exchange rate with the outside atmosphere must be considered. The most important mechanism of this kind is from atmospheric pressure fluctuations in which an increase in atmospheric pressure forces air into the tank which then mixes with the hydrogen-benzene mixture. The subsequent decrease in atmospheric pressure causes venting from the tank of the mixture -- the net effect being an increase in the tank`s oxygen concentration. Thus, enrichment occurs when the atmospheric pressure increases but not when the pressure decreases. Moreover, this natural atmospheric {open_quotes}pumping{close_quotes} is only important if the pressure fluctuations take place on a time scale longer than the characteristic mixing time scale (CMT) of the tank. If pressure fluctuations have a significantly higher frequency than the CMT, outside air will be forced into the tank and then out again before any significant mixing can occur. The CMT is not known for certain, but is estimated to be between 8 and 24 hours. The purpose of this report is to analyze yearly pressure fluctuations for a five year period to determine their statistical properties over 8 and 24-hour periods. The analysis also includes a special breakdown into summer and winter seasons and an analysis of 15-minute data from the SRTC Climatology Site.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035
- OSTI ID:
- 10107341
- Report Number(s):
- WSRC-TR-93-232; ON: DE94003818; TRN: 94:000883
- Resource Relation:
- Other Information: PBD: Jul 1993
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
TANKS
OXYGEN ENRICHMENT
PRESSURE MEASUREMENT
SAVANNAH RIVER PLANT
WASTE STORAGE
HAZARDS
ATMOSPHERIC PRESSURE
BENZENE
HYDROGEN
MIXING
STATISTICS
ANNUAL VARIATIONS
FLAMMABILITY
ORGANIC BROMINE COMPOUNDS
WATER
RADIOLYSIS
052002
054000
400600
WASTE DISPOSAL AND STORAGE
HEALTH AND SAFETY
RADIATION CHEMISTRY