Thermocouple tree system installation and operation in non-leaking ferrocyanide tanks, Hanford Site, Richland, Washington

The US Department of Energy (DOE) has prepared an environmental assessment (EA), DOE/EA-0809, to assess environmental impacts associated with installing and operating thermocouple tree (TCT) systems in 11 non-leaking Hanford Site single-shell ferracyanide-containing high-level waste tanks. The objective is to improve DOE's knowledge of ferracyanide waste temperatures, including the possible presence of discrete localized areas of elevated temperatures within the tanks (''hot spots''), by providing additional temperature monitoring instrumentation. DOE needs to take action to gain a better understanding of the potential for hot spots to exist within the tanks that could result in an explosion or release of radioactive material, and to better understand potential reactive behavior of the farrocyanide waste in order to resolve current Unreviewed Safety Questions declared for these tanks. Based on the evaluation in the EA, DOE has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NE PA) of 1969. Therefore, the preparation of an environmental impact statement is not required, and DOE is issuing this Finding of No Significant Impact