An experimental reactor which is designed to produce 250 MW

An experimental reactor, which is designed to produce 250 MW, can use either U-235 or Pu-241 fissile materials as fuel. If this reactor works for 1 year and is shut down for a two week maintenance work to be performed on it Compute the activity, in Bq, at the beginning of the maintenance work Which of the fuels is more expensive to use for the reactor, assuming the cost per gram for the two fuels is the same

Solution

The activity in BQ can be found from half life of the element and other constants, and varies inversely with Mole wt and 1/2 life.

Pu 241 is much more efficient thant U 235, so although it may be consumed faster it produces more energy.

If expensive means cost per gram, this depends on the market. U 235 costs aabout $25./gm, Pu 241 much higher.