After the initial cleanup effort at Three Mile Island,approximately 400,000 gallons of radioactive water remained in thebasement of the containment building of the Three Mile Island Unit2 nuclear plant. The principal sources of this radioactivity wereCs-137 at 156 μCi/cm^3 (5.772000 MBq) and Cs-134 at 26 μCi/cm^3(0.962 MBq). How many atoms per cm^3 of these radionuclides were inthe water at that time?
The answer is about 1.78 billion years, but I don't know how tosolve for it.
