Radioactive air emissions notice of construction use of a portable exhauster on single-shell tanks during salt well pumping
This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.07, portable exhausters for use on singleshell tanks (SSTs) during salt well pumping. Table 1-1 lists SSTs covered by this NOC. This GOC also addresses other activities that are performed in support of salt well pumping but do not require the application of a portable exhauster. Specifically this NOC analyzes the following three activities that have the potential for emissions. (1) Salt well pumping (i.e., the actual transferring of waste from one tank to another) under nominal tank operating conditions. Nominal tank operating conditions include existing passive breathing rates. (2) Salt well pumping (the actual transferring of waste from one tank to another) with use of a portable exhauster. (3) Use of a water lance on the waste to facilitate salt well screen and salt well jet pump installation into the waste. This activity is to be performed under nominal (existing passive breathing rates) tank operating conditions. The use of portable exhausters represents a cost savings because one portable exhauster can be moved back and forth between SSTs as schedules for salt well pumping dictate. A portable exhauster also could be used to simultaneously exhaust more than one SST during salt well pumping. The primary objective of providing active ventilation to these SSTs during salt well pumping is to reduce the risk of postulated accidents to remain within risk guidelines. It is anticipated that salt well pumping will release gases entrapped within the waste as the liquid level is lowered, because of less hydrostatic force keeping the gases in place. Hanford Site waste tanks must comply with the Tank Farms authorization basis (DESH 1997) that requires that the flammable gas concentration be less than 25 percent of the lower flammability limit (LFL). Safety analyses indicate that the LFL might be exceeded in some tanks during certain postulated accident scenarios. Also, the potential for electrical (pump motor, heat tracing) and mechanical (equipment installation) spark sources exist. Therefore, because of the presence of ignition sources and the potential for release of flammable gases, active ventilation might be required in some SSTs to reduce the ''time at risk'' while salt well pumping. For this reason, portable exhausters will be installed as a precautionary measure and used when flammable gas concentrations exceed 25 percent of the LFL during salt well pumping.
- Research Organization:
- WMH (US)
- Sponsoring Organization:
- ENVIRONMENTAL MANAGEMENT (US)
- DOE Contract Number:
- AC06-96RL13200
- OSTI ID:
- 797476
- Report Number(s):
- DOE/RL-97-09, Rev.3; TRN: US0201920
- Resource Relation:
- Other Information: PBD: 14 Jul 1999
- Country of Publication:
- United States
- Language:
- English
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