"For an idea about how much is 11,500 tons, one metric ton is 1000 kilograms or about 2200 pounds, which is close to an English ton. Water is about 8.5 pound per gallon, so one ton is about 260 gallons," said Gary Was, a professor of nuclear engineering at the University of Michigan. "So 11,500 tons is about 3 million gallons. A spent fuel pool holds around 300,000 gallons. So this amount of water is equivalent to the volume of roughly 10 (spent fuel pools)."
Source: CNN
