High-heat tank safety issues evaluation

Subsection (b) of Public Law 101-510, Section 3137, open-quotes Safety Measures for Waste Tanks at Hanford Nuclear Reservationclose quotes (PL 101-510), requires the Secretary of Energy to open-quotes identify those tanks that may have a serious potential for release of high-level waste due to uncontrolled increase in temperature or pressureclose quotes. One of the tanks that has been identified to meet this criteria is single-shell tank (SST) 241-C-106 (Wilson and Reep 1991). This report presents the results of an evaluation of the safety issue associated with tank 241-C-106: the continued cooling required for high heat generation in tank 241-C-106. If tank 241-C-106 should start leaking, continued addition of water for cooling could possibly increase the amount of leakage to the soil column. In turn, if the current methods of cooling tank 241-C-106 are stopped, the sludge temperatures may exceed established temperature limits, the long term structural integrity of the tank liner and concrete would be jeopardized, leading to an unacceptable release to the environment. Among other conclusions, this evaluation has determined that tank 241-C-106 contains enough heat generating wastes to justify retaining this tank on the list open-quotes Single-Shell Tanks With High Heat Loads (>40,000 Btu/H)close quotes and that to confirm the structural integrity needed for the retrieval of the contents of tank 241-C-106, an updated structural analysis and thermal analysis need to be conducted. Other findings of this evaluation are also reported