A spare mixing pump from the Hanford Grout Program was installed in Hanford double-shell waste Tank 241-SY-101 on July 3, 1993, after being modified to take advantage of waste stratification. It was anticipated that pump mixing would prevent large episodic flammable gas releases that had been occurring about every 100-150 days. A cautious initial test plan, called Phase A, was run to find how the pump and tank would behave in response to very brief and gentle pump operation. No large gas releases were triggered, and the pump performed well except for two incidents of nozzle plugging. On October 21, 1993, the next test series, Phase B, began, and the pump was applied more aggressively to mix the tank contents and mitigate uncontrolled gas releases. Orienting the pump in new directions , released large volumes of gas and reduced the waste level to a near-record low. Results of the entire period from pump installation to the end of Phase B on December 17, 1993, are presented in detail in this document. Though long-term effects require furtherevaluation, we conclude from these data that v the jet mixer pump is an effective means of controlling flammable gas release and that it has met the success criteria for mitigation in this tank. iii SZrMMARY A mixer pump was found to be effective in controlling and possibly eliminating large episodic flammable gas releases from Hanford Tank 241-SY-I01. A gas release event (GRE) is apparently initiated when a major portion of the gas-bearing sludge layer accumulates sufficient gas to become buoyant, pull flee from the surrounding material, rise through the surface crust, and release the trapped gas into the dome space. Mixer pump operation is intended to keep enough of the gas-generating material in suspension so that gas is released continuously instead of periodically in large, potentially dangerous GREs.. A spare mixing pump from the HartfordGrout Program was modified and installed in the tank on July 3, 1993, seven days after a typical GRE that met the safety criteria for pump installation. The modifications were made to take advantage of the density stratification in the waste, providing vertical v buoyant motion as well as high jet velocity to promote mixing. The initial pump operations in Phase A testing were extremely gentle, beginning with a series of daily pump 'bumps' intended to keep the pump nozzles clear. Because nozzle plugging did occur, bump speed and duration were increased, eventually arriving at the accepted five-minute period at 1000 rpm on July 26. There has been no nozzle plugging since then. Bumping was initially performed twice a day through mid-August and once a day through the start of Phase B testing October 17. By the end of Phase B, thrice-weekly bumping during nontesting periods became the rule. ACKNOWLEDGMENTS The authors wish to thank Jeanne Lecher for supplying plots of various data under high pressure and short notice, to our editor Sheila Bennett for working extra hours to put all the pieces together, and to Kathy Hildebrant for helping with th...
The mission of the U.S. Department of Energy's Federal Energy Management Program (FEMP) is to reduce the cost of Government by advancing energy efficiency, water conservation, and the use of solar and other renewable technologies. This is accomplished by creating partnerships, leveraging resources, transferring technology, and providing training and technical guidance and assistance to agencies. Each of these activities is directly related to achieving the requirements set forth in the Energy Policy Act of 1992 and the goals that have been established in Executive Order 13123 (June 1999), as well as supporting activities that promote sound management of Federal financial and personnel resources. The Pacific Northwest National Laboratory (PNNL) 1 supports FEMP mission in all activity areas. This document presents the findings of a technology market assessment for thermal energy storage (TES) in space cooling applications. The potential impact of TES in Federal facilities is modeled using the Federal building inventory with the appropriate climatic and energy cost data. In addition, this assessment identified acceptance issues and major obstacles through interviews with energy services companies (ESCOs), TES manufacturers, and Federal facility staff.
V ac voltage, alternating current WHC Westinghouse Hanford Company xiv * Star indicates recommended action.
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