Question
After a nuclear plant disaster, water that is being used to cool the reactor cores is contaminated with radioactivity. The cooling water flow rate is 255 cubic meters per day. Groundwater is also flowing into the plant and being contaminated at a rate of 86.0 cubic meters per day. All of this contaminated water must be collected In storage tanks to wait for treatment. Hundreds of storage tanks with a total volume of 121,000 cubic meters are being used to store the contaminated water. At the same time, water from the tanks is being treated at a rate of 125 cubic meters per day and discharged to the ocean. If the tanks are initially empty, how many days will it take to fill all the storage tanks?
Explanation / Answer
we have
filling rate of water in tank = cooloing water flow + ground water flow
= 255 + 86 cubic meter per day
= 341 cubic meter per day
and
exact rate = total filling rate - water being treated
= 341 cubic meter per day - 125 cubic meter per day
= 216 cubic meter per day
and
time = total volume / flow rate
= 121000 cubic meter / 216 cubic meter per day
= 560.19 days