Preliminary analysis of tank 241-C-106 dryout due to large postulated leak and vaporization

This analysis assumes that there is a hypothetical large leak at the bottom of Tank 241-C-106 which initiates the dryout of the tank. The time required for a tank to dryout after a leak is of interest for safety reasons. As a tank dries out, its temperature is expected to increase which could affect the structural integrity of the concrete tank dome. Hence, it is of interest to know how fast and how high the temperature in a leaky tank increases, so that mitigation procedures can be planned and implemented in a timely manner. This analysis is focused on tank 241-C-106, which is known to be high thermal tank. The objective of the study was to determine how long it would take for tank 241-C-106 to reach 350 degrees Fahrenheit (about 177 degrees Centigrade) after a postulated large leak develops at the bottom center of the tank. The temperature of 350 degrees Fahrenheit is the minimum temperature that can cause structural damage to concrete (ACI 1992). The postulated leak at the bottom of the tank and the resulting dryout of the sludge in the tank make this analysis different from previous thermal analyses of the C-106 tank and other tanks, especially the double-shell tanks which are mostly liquid.