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Radioactive air emissions notice of construction use of a portable exhauster on single-shell tanks during salt well pumping and other activities

Technical Report ·
DOI:https://doi.org/10.2172/362355· OSTI ID:362355

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) 61.96, portable exhausters for use on single-shell tanks (SSTs) during salt well pumping and other activities. The reference to `other activities` throughout this NOC means those activities described in Appendix A. The use of portable exhausters represents a cost savings feature because one portable exhauster can be moved back and forth between SSTS as schedules for salt well pumping or other activities dictate. A portable exhauster also could be used to simultaneously exhaust more than one SST during salt well pumping or during performance of other activities. The primary objective of providing active ventilation to these SSTS 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. Other activities also have the potential to release trapped gases by interrupting gas pockets within the waste. Hanford Site waste tanks must comply with the Tank Farms Safety Basis (OESH 1997) which requires that the flammable gas concentration be less than 25 percent of the lower flammability limit (LFL). The Los Alamos National Laboratory (LANL) safety analysis indicates 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 released flammable gases, active ventilation might be required in some SSTS to reduce the `time at risk` while salt well pumping or performing other activities. Thirty tanks remain to be salt well pumped. Determination of which of the 30 tanks have the potential to exceed the 25 percent LFL is continuing as this NOC is submitted.

Research Organization:
Fluor Daniel Hanford Inc., Richland, WA (United States)
Sponsoring Organization:
USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
DOE Contract Number:
AC06-96RL13200
OSTI ID:
362355
Report Number(s):
DOE/RL--97-09-Rev.1; ON: DE99050367; BR: EW3135000
Country of Publication:
United States
Language:
English